HIGH-STRENGTH THREE-DIMENSIONAL STRUCTURE AND METHOD OF MANUFACTURE

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates, in general, to flexible manufacturing processes such as preparing sheets of material for bending using punching, stamping, roll-forming, and similar processes and then bending the sheets into rigid three-dimensional structures. Various aspects of the invention relate to forming cooking appliances with adjustable configurations.

2. Description of the Related Art

Conventional techniques for mass producing three-dimensional structures require complex, work-intensive assembly processes. Typically, separate sheet materials and solid components are fastened together to form the structure. As the end-product increases in complexity, the assembly process becomes exponentially more complex and costly. Such conventional techniques suffer from a lack of flexibility and cost pressures.

By way of example, conventional appliances, such as cooking ranges, require the design and engineering of assembly lines and manufacturing systems as complex as some of the products produced. As such, the assembly lines and production facilities can not be modified easily. The appliance arrangements and configurations are likewise limited to increase efficiencies of scale and minimize unit costs.

Conventional cooking ranges and ovens include a skeletal frame and housing supporting one or more cooking compartments. Each compartment includes a top, body, and base member which are formed of multiple sheets of material and other components fastened together into a three-dimensional structure. The range or appliance further requires a complex structure to add rigidity to the product, such as front and rear frame structures. Each type of range also requires a unique assembly process. For example, a cooking range with a warming drawer requires different compartments and a different skeletal structure than one which includes two cooking compartments.

To take advantage of efficiencies of scale, assembly lines and processes are set up for each unique cooking range configuration. Customarily, manufacturers design a “range line” to accommodate various sizes and configurations. Manufacturers prepare specific tooling for each range line. When significant engineering design changes are made, the manufacturing line must be revised accordingly. Likewise, changes can not be made easily or cost efficiently between range lines, for example, when switching between a multiple-oven design and a single-oven design.

Furthermore, manufacturers must estimate the total products to be made of each range line when ordering parts. A large number of specific parts must be provided, each keyed to a specific range line. When production increases or decreases, the cost of materials and waste increases. For these and other reasons, the tool-up investment can be millions of dollars for a typical line of appliances and tens of millions of dollars for high-volume appliance lines.

More recently, methods have been developed for forming three-dimensional products, such as cooking appliances, from two-dimensional sheets of material. Such methods generally reduce tooling and production costs and increase manufacturing flexibility. Various methods of preparing sheet materials for precision folding along a desired bend line have been developed to this end. For example, U.S. Pat. Nos. 6,481,259, 6,877,349, 7,032,426, 7,152,449 and 7,152,450 describe various methods of preparing and folding sheet materials for forming three-dimensional objects having relatively high tolerances from substantially planar two-dimensional sheets. The folding-structures shown and described in the above patents promote so-called edge-to-face engagement and other phenomena to facilitate folding along a desired bending line.

The methods and structures described in the above-mentioned patents may be used to form three-dimensional structures for a variety of applications. With the recognition of the advantages of such methods, there is a need to expand the useful application of such methods.

The above methods provide three-dimensional structures with strength and rigidity in comparison to welded structures, but in many instances it may be desirable to provide three-dimensional structures capable of withstanding increased loading. For example, it may be desirable to form large complex structures having sufficient strength to satisfy design requirements without using (or at least reducing the need for) additional modifications to increase strength. Such additional modifications might include welding or attaching strengthening members like plates, gussets or other reinforcing members over joints, increasing the thickness of material, or using support structures. In some cases, even the use of support structures can not increase the structural strength to a sufficient degree. In other cases, the use of such additional structures, which increases the bill of materials, is cost-prohibitive.

In the context of cooking appliances, for example, there is the additional problem of accumulation of grease, food, and other materials upon cooking surfaces. Such grease and debris is messy, unsightly, and smells. Grease also presents a fire hazard at high operating temperatures. The accumulation of grease and other matter also decreases the performance of appliances by lowering the thermal reflectivity of the interior surfaces. The use of the above-described folding technologies has been lacking thus far because slits, grooves, and the like provide especially troublesome sources—in the slits and along the crook of the bends-for the accumulation and trapping of grease.

Conventional appliances have used disposable liners and self-cleaning cycles to reduce or eliminate the build-up of grease. Cooking utensils such as pots and pans commonly utilize non-stick coatings, but at present, such coatings have been uneconomical for application to oven compartments. One reason for the high cost of applying coatings to conventional ovens arises from the large surface area to be covered. Because conventional ovens are assembled from a large number of parts, each of which requires whole covering in the treatment the total surface area to be covered is exponentially large. In addition, coatings such as polymers (e.g. Teflon® or PTFE) and vitreous enamels chip and peel off surfaces easily during assembly when subjected to bending, twisting, and hits from various moving parts involved with conventional manufacturing processes. For this reason, such coatings, if used at all, are applied after assembly.

The peeling of coatings is especially troublesome when used on sheet materials prepared for folding. During folding, the sheet of material along the bend line is subjected to bending, twisting, and stretching. Inelastic and rigid coatings easily peel off the sheet along the bend line. Even more flexible coatings tend to separate due to the different rate of stretching between the coating and the sheet surface to which it adheres.

Another concern of appliance manufacturers is maximizing the amount of cooking space without increasing the dimensions of the overall appliance or sacrificing structural integrity. The use of additional support structures and the like to bent sheets or assembled frames reduces the amount of space available for cooking.

What is needed is a three-dimensional structure and method of manufacture which overcomes the above and other disadvantages. What is needed is a structure that can be manufactured with flexible and cost-efficient manufacturing techniques.

What is needed is a rigid structure with reduced associated costs. What is needed is an adjustable structural configuration and design.

What is needed is a three-dimensional structure formed from a folded sheet of material that minimizes the problems with bend lines described above.

BRIEF SUMMARY OF THE INVENTION

Various aspects of the invention are directed to a three-dimensional structure including a housing formed from at least one two-dimensional sheet of material including a plurality of bend lines defining outer sides of the housing, at least two of the bend lines including a positioning structure therealong; and an inner structure within the housing, the inner structure having a periphery and a plurality of support flanges extending outward from the periphery, each support flange extending towards a respective bend line of the housing and including a fastening structure on an outer edge thereof. The fastening structure of each inner structure support flange is configured to cooperate with a respective positioning structure of the housing to support the inner structure within the housing.

In various embodiments, the positioning structure is a bend-controlling displacement. Each bend line may include a plurality of bend-controlling displacements.

At least one support flange may be configured to be fastened to the housing without discrete fasteners. At least two of the plurality of support flanges may extend from opposite sides of the inner structure. The inner structure may be formed of at least one inner sheet of material, and the at least one inner sheet includes an inner bend line, and at least one of the support flanges of the inner structure may be monolithically formed with the at least one inner sheet, and the inner bend line defines a border between at least one of the support flanges and an inner side. The at least one support flange may be substantially straight. The at least one support flange may extend from the inner structure to the housing at substantially 45 degrees from a plane defined by the inner side.

In various embodiments, the inner structure is formed of at least one sheet of material, and the at least one sheet includes a plurality of inner bend lines, and at least two support flanges of the inner structure are monolithically formed with the at least one sheet, and the inner bend lines define a border between the inner side and the at least two support flanges.

At least one fastening structure may include a tab, and a respective positioning structure includes an aperture along a respective bend line of the housing, and wherein the tab is inserted into the aperture thereby fastening a respective support flange of the inner structure to the housing. The inner structure may be formed from at least two sheets of material each having an inner bend line. One of the two sheets and at least one of the support flanges of the inner structure may be monolithically formed, and the inner bend line of the one of the two sheets defines a border between the inner side and at least one of the support flanges. The other of the two sheets may include a lip portion, wherein the inner bend line of the other of the two sheets defines a border between another inner side and the lip portion, and the lip portion extends towards the inner structure. The lip portion may be fastened to the at least one of the support flanges. The lip portion may fasten to the at least one flange without discrete fasteners.

The housing may be configured for mounting a modular control panel thereto. The housing may include at least one aperture providing a guide path for electrical wiring.

In various embodiments, the three-dimensional structure is an appliance. In various embodiments, the three-dimensional structure is an oven.

Various aspects of the present invention are directed to a three-dimensional structure including a sheet of material bent along a plurality of bend lines, the bent sheet of material forming a plurality of walls defining an interior volume and having a predetermined cross-section, at least one bend line defining a fold-out tab portion in one of the walls. The tab has a peripheral shape complementary to the predetermined cross-section. At least one side of the folded tab engages an immediately adjacent, corresponding wall thereby defining the predetermined cross-section of the plurality of walls.

In various embodiments, the tab portion nests within the interior volume. In various embodiments, the periphery of the tab portion abuts at least two corresponding walls of the respective plurality of walls. The tab portion may be configured to support the wall structure and further configured as a cross-brace for the walls.

The plurality of bend lines may be defined by a plurality of bend-facilitating structures. The bend-facilitating structures may be displacements.

In various embodiments, the tab portion fastens to any of the plurality of walls. The tab portion may fasten to the wall without fasteners. The tab portion may snap into the interior volume.

In various embodiments, the sheet of material includes a coating. The three-dimensional structure may be part of an oven housing, and the sheet of material may be pre-treated with a non- stick coating. The structure may be an appliance. The appliance may be a cooking range.

Various aspects of the invention are directed to a three-dimensional structure including a structure formed from a sheet of material configured for bending along a plurality of bend lines, each bend line defined by a plurality of bend-inducing structures, the sheet of material including a first peripheral flange portion along a first of the bend lines extending along a first panel portion of the sheet of material, and a second peripheral flange portion along a second of the bend lines extending along a second panel portion of the sheet of material. The first peripheral flange portion may overlap a portion of the second panel portion sheet and the second peripheral flange portion may overlap a portion of the first panel portion such that the first and second bend lines are immediately adjacent and parallel to one another thereby forming a multiple-sheet-thick framework of along a periphery of the three-dimensional structure. The three-dimensional structure may further include a rigid inner structure having a substantially straight support flange. The support flange may extend from the inner structure toward the first and second bend lines.

Various aspects of the invention are directed to a three-dimensional structure including a structure formed from at least one sheet of material configured for bending along a plurality of bend lines, each bend line defined by a plurality of bend-inducing displacements in the thickness direction of the sheet of material, the bend lines of the at least one sheet defining a first portion and a second portion of the at least one sheet of material. The bend-inducing structures forming the first portion may nest within the bend-inducing structures forming the second portion when the at least one sheet of material is folded into a three-dimensional structure.

Various aspects of the invention are directed to a three-dimensional structure including a sheet of material for bending along a plurality of bend lines, each bend line defined by a plurality of bend-inducing structures, the sheet of material including a first peripheral flange portion along a first of the bend lines extending along a first panel portion of the sheet of material, and a second peripheral flange portion along a second of the bend lines extending along a second panel portion of the sheet of material. The first peripheral flange portion may align with a portion of the second panel portion sheet and the second peripheral flange portion may align with a portion of the first panel portion such that the first and second bend lines are immediately adjacent and parallel to one another.

Various aspects of the present invention are directed to a three-dimensional structure including a structure formed from a sheet of material. The sheet of material is configured for bending along a bend line, the bend line defined by a plurality of bend-facilitating structures. The bend line defines a first portion and a second portion of the sheet of material. Each of the first portion and the second portion includes a pre-formed bend angle flange defined by a hard, pre-formed bend and extending from an end opposite the bend line. The sheet of material is bent along the bend line such that the pre-formed bend of the first portion is aligned with the pre-formed bend of the second portion.

Various aspects of the present invention are directed to a three-dimensional structure including a structure formed from a sheet of material. The sheet of material is configured for bending along a bend line, the bend line defined by a plurality of bend-facilitating structures. The bend line defines a first portion and a second portion of the sheet of material. Each of the first portion and the second portion includes a pre-formed bend angle flange defined by a hard, pre-formed bend and extending from an end opposite the bend line. The sheet of material is bent along the bend line such that a section of the first portion overlaps a section of the second portion thereby forming a multiple-sheet-thick framework.

In various embodiments, the bend-facilitating structures are displacements. In various embodiments, the three-dimensional structure forms a miter joint. The first section and second section may abut one another. The first section and second section may be pressed together. The first section and second section may lie substantially flat against each other. In various embodiments, each of the pre-bends are positioned adjacent one another. The bend line may be remote from each of the pre-formed bend angle flanges.

In various embodiments, the sheet of material includes a plurality of bend lines, the sheet of material configured for bending along the bend lines into a three-dimensional structure. The first pre-formed bend angle flange and the second pre-formed bend angle flange may form a corner of the three-dimensional structure.

In various embodiments, the overlap of the first section and second section seal an inner portion of the bend line after bending is complete. In various embodiments, the sheet of material includes a coating. The structure may be part of an oven housing, and the sheet of material may be pre-treated with a non-stick coating. The structure may form part of an appliance. The appliance may be a cooking range.

Various aspects of the present invention are directed to an oven including an oven compartment having sidewalls, a top and a back, and a removable bottom disposed within the oven compartment and adjustably mounted with respect to the sidewalls.

In various embodiments, at least one of the sidewalls and back include mounts for slidably engaging the bottom. The mounts may be rack mounts. An end or portion of the bottom may be configured to engage the mounts on the back. The sidewalls may include racks for engaging at least one of shelves, drawers, and racks.

In various embodiments, the oven compartment may including an oven housing for housing the oven compartment. The oven compartment may engage inner walls of the housing.

In various embodiments, the bottom includes a heater element, at least one insulating layer adjacent the heater element, a top pan disposed above the heater element and the insulating layer, and a bottom pan disposed below the heater element and the insulating layer. The bottom may include apertures for heat transfer from the heater element to the oven compartment.

The oven may include a second cooking compartment positioned below the oven compartment, the bottom being configured to form a top of the second cooking compartment. The bottom may be configured to heat the second cooking compartment.

In various embodiments, walls of the oven compartment may be formed from a single sheet of material configured to bend along a plurality of bend lines. The bend lines may be defined by a plurality of bend-facilitating structures.

In various embodiments, the cooking surfaces in the oven housing are pre-treated with a non- stick coating.

The three-dimensional structures and methods of the present invention have a number of features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated in and form a part of this specification, and the following Detailed Description of the Invention, which together serve to explain the principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary cooking range in accordance with various aspects of the present invention.

FIG. 2 is a perspective view of the cooking range of FIG. 1, illustrating the cooking range with the stovetop range, warming drawer, and front doors removed.

FIG. 3 is a front view of the cooking range of FIG. 2.

FIG. 4 is a perspective view of the cooking range of FIG. 2.

FIG. 5 is a perspective view of the oven compartment of FIG. 1, illustrating the housing and front frame member removed.

FIG. 6 is a perspective view of the top of the oven compartment of FIG. 1.

FIG. 7A is an enlarged perspective view of the oven body of FIG. 1, illustrating the mounts in the sidewalls and the top removed. FIG. 7B is an enlarged view of features of the oven body of FIG. 7A.

FIG. 8 is an enlarged front view of the oven compartment and body of FIG. 1, illustrating the bottom on lower mounts and a plurality of connection terminals.

FIG. 9A is a rear view of the bottom of FIG. 1, illustrating the heater element disposed between a top pan, bottom pan, and insulating layer and grooves in the sides of the bottom for engaging mounts in the oven compartment.

FIG. 9B is a side view of the bottom of FIG. 9A.

FIG. 10A is a front view of the range of FIG. 2.

FIG. 10B is a front view of exemplary configurations of the range of FIG. 2, illustrating the bottom in various exemplary positions and orientations.

FIG. 11 is a perspective view of the rear, underside of the bottom of FIG. 9.

FIG. 12 is a perspective view of the underside of the bottom of FIG. 11, illustrating the bottom with the bottom pan removed.

FIGS. 13A-13C-1 are schematic views of a corner of the oven compartment of FIG. 2, illustrating bending of the sheet along a bend line and positioning within a housing. FIG. 13C-2 is an enlarged schematic view of a portion of the oven compartment wall of FIG. 13C-1.

FIGS. 13D-13E are schematic views of a corner of an oven compartment similar to that of FIG. 2, illustrating bending of the sheet along a bend line to form a curved overlap structure.

FIGS. 13F-13G are schematic views of a corner of an oven compartment similar to that of FIG. 2, illustrating bending of the sheet along a bend line to form a rounded corner.

FIG. 13H is a schematic view of a corner of an oven compartment similar to that of FIG. 2, illustrating a corner without a bend line.

FIG. 13I is a schematic view of corners of an oven compartment similar to that of FIG. 2, illustrating bending of the sheet along bend lines to form various corner configurations.

FIG. 13J is a schematic view of a corner of an oven compartment similar to that of FIG. 2, illustrating bending of the sheet along a bend line to form various corner configurations.

FIG. 13K is a schematic view of a corner of an oven compartment similar to that of FIG. 2, illustrating bending of the sheet along a bend line to form various corner configurations.

FIG. 14 is a perspective view of the oven compartment of FIG. 2 positioned adjacent the back panel structure and sidewall of the housing.

FIG. 15A-1 is a perspective view of the back panel structure of the range of FIG. 1. FIG. 15A-2 is an enlarged view of the corner post of the range of FIG. 1.

FIG. 16 is an enlarged perspective view of the back panel structure of FIG. 15, illustrating a corner post with a bent tab portion.

FIGS. 17A-17J are schematic figures illustrating a process for forming a three-dimensional structure similar to that shown in FIG. 1. FIGS. 17A-1, 17B-1 to 17B-4, 17E-1, 17F-1, and 17F-2 are enlarged views of features of the sheets of FIG. 17.

FIG. 18 is a perspective view of an exemplary oven assembly in accordance with various aspects of the present invention.

FIG. 19 is a pictorial view of two sheets of material which may be used to form a housing of the oven assembly of FIG. 18.

FIG. 20 is a pictorial view of the two sheets of material shown in FIG. 19 having been bent along peripheral bend lines to form peripheral flanges.

FIG. 21A through FIG. 21P are sequential perspective views of a method of manufacturing the oven box of FIG. 18 in accordance with some aspects of the present invention.

FIG. 22 is a perspective view of an exemplary oven box of the oven assembly of FIG. 18.

FIG. 23A is a cross-sectional view of the oven of FIG. 21N taken along the line 6-6 of FIG. 21N, illustrating positioning of an inner structure inside a housing similar to FIG. 13. FIG. 23B, 23C and 23D are cross-sectional views of alternatives thereof.

FIG. 24 is a perspective view of the oven of FIG. 18 illustrating mounting of an instrument panel in accordance with the present invention.

FIG. 25 is an enlarged perspective view of the oven of FIG. 24 illustrating the mounting points for a door assembly in accordance with the present invention.

FIG. 26 is a perspective view of the oven of FIG. 18 shown assembled on the workbench.

FIG. 27 is a perspective view of a fastener configuration of the oven of FIG. 18 in accordance with the present invention.

FIG. 28 is a perspective view of the sheet of material and workbench of FIG. 21A illustrating folding of the sheet of material in accordance with the present invention.

FIG. 29A is a perspective view of another exemplary oven box of the oven assembly of FIG. 18, while FIGS. 29B, 29C and 29D show the oven box in various stages of assembly.

FIG. 30 is a perspective view of a portion of the oven box of FIG. 29 illustrating enameling in-the-flat.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

Turning now to the drawings, wherein like components are designated by like reference numerals throughout the various figures, FIG. 1 shows a folded three-dimensional structure, generally designated 230, in accordance with some aspects of the present invention. In one exemplary embodiment, the three-dimensional structure is a housing structure with a hinged cover and inner compartment, for example, an appliance, such as cooking appliances and combinations, a dishwasher, a washing machine, or a dryer, or a container, such as a safe, a toolbox, or a cabinet. For convenience, various embodiments will be described herein with respect to the exemplary case of a cooking range. However, one skilled in the art will understand that the present invention as described herein is generally applicable to numerous applications requiring flexible and precise manufacturing of three-dimensional structures.

Thus, the depiction of an appliance is merely exemplary. The teachings of the present inventions for precision bending are also applicable to the production of numerous other three-dimensional (3D) structures including, but not limited to, electronic component chassis, automotive components and chassis, transport components and chassis, construction components and chassis, appliances parts and chassis, truck components and chassis, architectural components and structural members, aerospace components, commercial coolers, HVAC systems, and more. The structures and method of the present inventions may be applied in various applications whether residential, commercial, or industrial. That is, the teachings of the present application are applicable to a wide variety of three-dimensional products and structures including those that are formed by folding two- dimensional sheet materials. Such 3D structures may also benefit in that the present invention would allow reducing the 3D structures to their flat forms to facilitate repackaging and reshipping. Such features are suitable for producing reusable shipping containers and the like.

One will appreciate that more recent techniques for manufacturing appliances and the like may involve preparing major components from one or more folded sheets of material. The use of folded sheets reduces the tools, parts, time and assembly steps required to manufacture the structure. Such techniques utilize technology for preparing sheet materials for precision folding along a desired bend line. For example, U.S. Pat. Nos. 6,481,259, 6,877,349, 7,032,426, 7,152,449 and 7,152,450, incorporated herein in their entirety for all purposes, describe various methods of preparing and folding sheet materials for forming three-dimensional objects having relatively high tolerances from substantially planar two-dimensional sheets.

In many aspects, the sheet materials of the present inventions are similar to those disclosed by U.S. Pat. No. 6,481,259, U.S. Pat. No. 6,877,349, U.S. Pat. No. 7,152,449, U.S. Pat. No. 7,152,450, U.S. patent application Ser. No. 10/821,818 (Pub. No. 2005/0005670), U.S. Pat. No. 7,032,426, U.S. Pat. No. 7,263,869, U.S. Pat. No. 7,222,511, U.S. patent application Ser. No. 11/357,934 (Pub. No. 2006/0261139), U.S. patent application Ser. No. 10/952,357 (Pub. No. 2005/0064138), U.S. patent application Ser. No. 11/384,216 (Pub. No. 2006/0207212), U.S. patent application Ser. No. 11/080,288 (Pub. No. 2005/0257589), U.S. patent application Ser. No. 11/374,828 (Pub. No. 2006/0213245), U.S. patent application Ser. No. 11/180,398 (Pub. No. 2006/0021413), U.S. patent application Ser. No. 11/290,968 (Pub. No. 2006/0075798), U.S. patent application Ser. No. 11/411,440 (Pub. No. 2007/0113614), U.S. Provisional Patent Application No. 60/665,577, U.S. patent application Ser. No. 11/386,463 (Pub. No. 2006/0277965), and U.S. Provisional Patent Application No. 60/854,846, the entire contents of which patents and patent applications are incorporated herein for all purposes by reference.

With reference to FIGS. 1-2, cooking range 230 includes a housing 232 and range components, generally designated 233, some of which may be pre-assembled components and others of which may be assembled on-site. In some aspects, the cooking range is similar to conventional cooking ranges, such as the ones disclosed by U.S. Pat. No. 2,423,863 to Wales, the entire content of which is incorporated herein by this reference.

The cooking range may be provided with a cooking range top or stove top, generally designated 235, oven 237, and warming drawer 139. As will be described below, the cooking range of the present invention allows for changing the range configuration with greater ease. For example, the cooking range may be provided with multiple ovens, a microwave, warming drawers, utility drawers, various cooking tops, and other components and consumer features.

Suitable materials for the cooking range and components include, but are not limited to steel, stainless steel, aluminum, ceramics, porcelain, composites, and the like. It may be desirable to treat one or more of the range and components for aesthetic or functional purposes, such as to increase reflectivity or reduce build-up of grease. Such treatments may include the addition of a coating material such as paint, porcelain, enamel, polymer, and the like. A portion or all of the cooking surfaces may be treated with a non-stick coating including, but not limited to, polytetrafluoroethene, polytetrafluoroethylene (PTFE), and vitreous enamels. Laminates, chemical treatment, polishing, the use of liners, and the like may also be utilized depending on the application.

The material may be pre-treated, meaning, treated prior to folding and/or assembly. The material may also be treated after such processing. In comparison to conventional treatment processes, the method of forming the structure in accordance with the present invention yields several advantages. In the example of applying non-stick coatings, application and firing of porcelain in-the- flat is faster and more consistent. Cleaning, polishing, and many other treatment and finishing processes can be performed better and at reduced costs when done on flat sheets versus odd-shaped, three-dimensional structures.

Referring to FIGS. 2-8, exemplary oven 237 includes an oven compartment 240 having sidewalls 242, a top 244, and a back 246, which together form a body 247, and a bottom 249. Conventional oven compartments are fabricated from separate sheets of materials welded or joined together to form the wall sections. In various embodiments, oven compartment 240 may be formed from one sheet of material folded into oven compartment 240 and secured in place. The oven compartment may also be formed of a sheet folded to form the body and a top lid fastened thereto.

The front of the body may be covered with a conventional front frame member 251 or left open. The front frame member adds rigidity to the oven compartment and also serves to fasten the compartment within housing 239. The oven compartment includes flanges 253 along the front edge that fasten to the front frame member. The oven compartment includes various other flanges and fastening structures for positioning the compartment within the housing. Unlike conventional appliances, the structure of the present invention does not require an intricate front frame structure to lend rigidity to the overall structure and system. The front frame member described may be a thin sheet of material. Although it may be configured as a rigid structural member, one will appreciate that the compartment described has improved rigidity in and of itself. Thus, in comparison to conventional appliances, the appliance and oven compartment of the present invention reduces the bill of materials and complexity of the system while increasing flexibility.

Oven body 247 may include features integrated into the structure to cooperate with shelves, racks, subassemblies, rotisseries, and the like. For example, the compartment includes racks 254 that engage conventional shelves. The compartment may also include other features such as apertures to exhaust air and a convection fan.

Compartment 240 includes bottom 249, which can be attached to or released from the compartment. The bottom may engage body 247 or may support the body. In various embodiments, the bottom is disposed within the oven compartment and may be removed. The position of the bottom within the compartment may be adjusted thereby modifying the oven compartment size and configuration without modifying the whole oven.

Referring specifically to FIGS. 9-12, bottom 249 includes a heater element 256, an insulating layer 258, a top pan 260, and a bottom pan 261. The insulating layer is positioned below the heater element and provides thermal insulation to the bottom pan. The top pan and bottom pan enclose the heater element and insulating layer on at least two sides. The rear end of the bottom may remain open to aid in plugging the heater element into the back of the oven. The front of the bottom is shown closed by the top pan to protect consumers from the heater element and to provide a pleasing aesthetic front.

Top pan 260 has a recessed top portion 263 with an outer lip 265. The outer lip helps to retain food and grease on the top of bottom 249. In some cases, it may be desirable to provide a disposable or removable liner on top 263 to aid the cleaning process.

Top pan 260 includes apertures 273 to allow combustion and/or convection heat to escape from bottom 249, and in particular, from heater element 256. Fans and other elements may be provided to facilitate airflow through the bottom.

While the bottom has been described in the context of a electric heating, one will appreciate that the bottom may be modified depending on the application. The bottom and/or oven may be configured for gas, electric, or other heating configurations. For example, in the case of an electric oven without convection, the bottom may be sealed without apertures. The bottom may also be configured for radiant, infrared, microwave or combinations of the same to name a few. The heater element configuration may also be modified depending on the desired performance parameters and other factors.

Referring back to FIGS. 7-12, oven body 247 is configured to receive bottom 249. In various embodiments, mounts 267 are provided on sidewalls 242 and/or back 246 to engage and fix the bottom in the oven body. The mounts shown in FIGS. 7-8 slidably engage the bottom. Specifically, sides of the bottom include v-shaped grooves 268 configured to engage rails formed as mounts. The height of the bottom relative to the sidewalls may be adjusted by sliding the bottom on a selected set of mounts.

The bottom and oven compartment may be modified as would be understood by one skilled in the art from the foregoing. For example, the bottom may engage the oven compartment walls with clips, hooks, tabs, and similar fastening devices. Removal or adjustment may not be required for all applications. In various embodiments, the bottom is permanently fastened into a selected position in the oven compartment during assembly. The means for fastening the bottom in the oven compartment include, but are not limited to, rivets, twist-tabs, buttons, and more.

The oven compartment may include any other configuration to receive the bottom at various locations as will be understood from the foregoing. The mounts may be integrally formed with the sidewalls of the oven compartment. The mounts may include a linear section and a grooved section to lock the bottom into position and/or positive haptic feedback during assembly. In various embodiments, the back of the oven body may be configured with grooves, slots, fasteners, and the like to engage bottom 249. The mounts may also serve as rack mounts whereby the unused mounts can receive shelves and the like.

During assembly, one pair of the plurality of mounts is selected depending on the oven configuration. The bottom is positioned on the mounts and secured in position. Connection terminals 270 may be provided for each of mount pairs 267. Thus, the bottom slides into place and engage a respective connection terminal. Thereafter the housing is assembled around the oven compartment. The bottom may also be configured to connect to the oven compartment via alternative arrangements. For example, flexible wiring may be used such that a single connection terminal can connect to the bottom in a variety of positions.

The positioning of the bottom in the oven may vary depending on the application. For example, if the bottom position is intended to be adjusted by a consumer, the oven may include mounts or other receiving members to adjustably receive and release the bottom. By contrast, if the bottom is intended to be positioned by the manufacturer based on a product type, the bottom may be configured to permanently fix into position in the oven. Additionally, the appliance may likewise be configured based on the intended use. For example, the oven may include a single large door to cover the entire oven compartment if the bottom is to be adjusted by a consumer or fitted with multiple doors if the bottom is to be permanently fixed by the manufacturer. The doors may also be configured based on the application and appliance configuration. For example, the doors may swing out laterally as opposed to opening in an up-and-down fashion.

One will appreciate that the structure described provides increased modularity over conventional structures and appliances. One will understand from the description herein that the structures and components may be modified to adjust the height, width, and other specifications simply and precisely. The position and orientation of various assemblies may be modified in accordance with the present invention. For example, the dimensions and orientation may be modified by changing the shape of the sheet of material and positioning the bottom in a different location.

As shown in FIG. 10, a variety of configurations may be obtained simply by adjusting the height and configuration of bottom 249 within oven compartment 240. Thus, a single oven compartment can accommodate a variety of oven configurations. Moreover, the configuration may be adjusted merely by selecting a location for the bottom without complicated changes to the manufacturing set-up, assembly process, parts ordering process, and the like.

In various embodiments, bottom 249 is positioned above the bottom of oven compartment sidewalls 242 and a second cooking or warming compartment is provided below the bottom. The second cooking compartment may be heated from above by bottom 249, or additional heating elements may be utilized such as one positioned in the floor of the range. The bottom may also be configured for a vertical orientation whereby a side-by-side configuration is provided. The appliance and oven may also include more than one bottom in various configurations.

In various embodiments, oven body 247 is formed from a folded, single sheet of material. The sheet of material is prepared for bending along a bend line 279 and folded during the process of making the cooking range 230. The sheet may be a monolithic sheet of material or several sheet joined together. In many aspects, the sheet materials of the present inventions are similar to those disclosed by the above-mentioned '259, '349, '426, '449, and '450, as well as U.S. patent application Ser. No. 10/821,818 (Pub. No. 2005/0005670), U.S. Pat. No. 7,032,426, U.S. Pat. No. 7,263,869, U.S. Pat. No. 7,222,511, U.S. patent application Ser. No. 11/357,934 (Pub. No. 2006/0261139), U.S. patent application Ser. No. 10/952,357 (Pub. No. 2005/0064138), U.S. patent application Ser. No. 11/384,216 (Pub. No. 2006/0207212), U.S. patent application Ser. No. 11/080,288 (Pub. No. 2005/0257589), U.S. patent application Ser. No. 11/374,828 (Pub. No. 2006/0213245), U.S. patent application Ser. No. 11/180,398 (Pub. No. 2006/0021413), U.S. patent application Ser. No. 11/290,968 (Pub. No. 2006/0075798), U.S. patent application Ser. No. 11/411,440 (Pub. No. 2007/0113614), U.S. Provisional Patent Application No. 60/665,577, U.S. patent application Ser. No. 11/386,463 (Pub. No. 2006/0277965), and U.S. Provisional Patent Application No. 60/854,846, the entire contents of which patents and patent applications are incorporated herein in their entirety for all purposes by reference thereto.

Other bend-facilitating structures are envisioned as being within the scope of the present invention. Such structures generally enable locating and positioning a respective bend line during bending. For example, the structures may be used to determine a location in the sheet of material where the bend will occur and may also position respective parts, including edges, faces, and the like, of the sheet of material during bending. The structures may be further configured to facilitate bending of the sheet of material with minimal use of tools and force.

Some applications may call for surfaces with increased reflectivity, reduced accumulation of grease, and other characteristics. It has been found that coatings and laminates can provide an effective way to alter the characteristics of the materials forming the oven compartment. However, coatings, laminates, and the like tend to chip or peel off when used in conjunction with folded sheets prepared using the above techniques. The sheet of material undergoes bending, twisting, and stretching that make it difficult to effectively coat the sheet in the region of the bend line.

With particular reference to FIGS. 7 and 13-14, a sheet of material 275 may include a structure to improve the use of folding techniques with surface and material preparations. The sheet of material is prepared with a plurality of bend-facilitating structures that define a bend line 279. The bend-facilitating structures may slits, grooves, displacements, perforations, and the like.

In various embodiments, the sheet of material and bend line are prepared to form an overlap structure 281 that seals the bend line at a remote location from the oven interior. The bend line divides the sheet material into a first portion 282 and a second portion 284. Each of the first portion and the second portion includes a pre-formed bend angle flange 286 defined by a pre-formed bend 303′. The angle flange extends from an end opposite the bend line at an angle such that the sheet on each side of the bend line forms an angle. During bending, the first portion and the second portion approach each other until they abut one another. “Abut” refers to a point at which the first and second portion apply a contact force against other. Thus, one portion overlays the other thereby forming a multiple-sheet-thick framework. “Overlap structure” as used herein refers to the structure formed by folding the sheet of material having pre-formed angle flanges until the first and second portions are adjacent one another.

The sheet may also be formed and bent such that hard, pre-formed bends 303′ align and lie adjacent each other. In various embodiments, the sheet of material is configured such that ends of the sheet are bent slightly past a point at which the pre-formed bends make contact. In various embodiments, the pre-formed bends are each slightly less than 135°. The sheet of material is bent along the bend line until the pre-formed bends make contact, which is slightly before 90°. Thereafter, the sheet is bent further until a 90° corner is formed and the sheet is slightly pre-loaded with a compressive force on the contact point between the pre-formed bend angles. In this way, pressure is applied to enhance the seal of the portion of the sheet which overlaps.

Although described as “pre-formed,” one will appreciate that the angle may be formed before or after the other processes described herein. For example, the flanges may be formed from a substantially flat sheet prior to or after bending along the bend line.

As described herein, “pre-formed bend” refers to a rigid, fixed bend. For example, sheet material 275 resembles angle brackets joined along a bend line. Each pre-formed angle is formed by working the material or using other conventional techniques to effectuate a rigid bend angle. By contrast to the bending techniques referred to above, working the material causes the material to undergo permanent changes and hold its shape. From another viewpoint, the pre-formed bend is differentiated by the bend line because the bend line acts likes a hinge whereas the pre-formed bend is relatively rigid. Indeed, working the material to form the pre-formed bend is intended to change the shape of the sheets and resist bending back. Although the bending techniques referred to above promote bending, such techniques do not resist bending back towards the original shape without the addition of features such as snaps and angle locks. In comparison, the pre-formed bend is formed using conventional techniques that fix the angle and shape much like the original shape of the sheet. The energy required to change the bend angle would be akin to that required to bend any other portion of the sheet.

As shown in FIG. 13B-13C, the framework described forms what resembles reverse miter joint. In the folded position, the first and second portion lie substantially flat against each other. The pre-formed bend angle flange extends from the first and second portion at a pre-formed or pre- determined bend angle. The pre-formed bend angle defines a base of the bend angle flanges, and the base of each portion may lie adjacent each other. The bend line lies at an opposite end of the first and second portion from the pre-formed bend angle. Thus, the bend line is situated remote from the engagement region of the pre-formed bend angles.

Although the structure has thus far been described as portions of the sheet abutting one another to form a multiple-sheet-thick framework, one will appreciate that other configurations and modifications may be employed in accordance with the present invention.

Referring to FIGS. 13D-13E, an alternative framework in accordance with various aspects of the present invention is shown. A sheet of material 275′ is similar to sheet of material 275. The sheet of material includes a bend line 279′. The bend line may be defined by a plurality of bend-facilitating structures. In various embodiments, the sheet of material and bend line are prepared to form an overlap structure 281′ similar to overlap structure 281 described above. The bend line divides the sheet material into a first portion 282′ and a second portion 284′. Each of the first portion and second portion includes curved portions 284′ proximate the bend line. The first portion includes a pre- formed bend angle flange 286′ defined by a pre-formed bend 303′. The angle flange extends from an end opposite the curved portion. When the sheet of material is bent along the bend line, the first portion and the second portion approach until the curved portions engage or contact one another. The engagement of the curved portions serves to fluidly seal the bend line.

Referring to FIGS. 13F-13G, an alternative framework in accordance with various aspects of the present invention is shown. A sheet of material 275″ is similar to sheets of material 275 and 275′. The sheet of material includes a bend line 279″. Instead of a substantially straight pre-formed bend angle flange, the sheet of material includes curved flange portions extending from pre-formed bend curves 306″. When the sheet of material is bent, sections of the sheet form an overlap structure and the curved flanges form a smooth or rounded corner. The smoother corner provides further sealing from food crumbs, grease, and the like. Although the curved flange portions are smooth curves and mirror each other, other shapes and configurations may be employed in accordance with the present invention.

Referring to FIGS. 13H-13K, various other framework configurations are within the scope of the invention. The sheet of material may be prepared such that the overlap structure is positioned within the bent structure or inside the interior volume after bending (shown, e.g., in FIG. 13J). The overlap structure may also have various shapes and configurations. With reference to FIGS. 13D-13E and 26K, the overlap structure may have a hook shape. It has been found that such a shape reduces leakage of microwave energy and radiation.

The treatment of the bend line may differ depending on the application. Modifications may be made to increase the stiffness and rigidity of the resulting structure such as welding or fastening the sheet together after bending.

Other applications may require the structure to be fluid tight. In such applications, it may be desirable to provide an elastic, fluid-resistant material such as a rubber on the interior of the first and second portions such that contact between the two forms a tight seal. Some applications may not require a tight seal of the bend line, in which case the sheet may only be partially bent and the first and second portion do not abut one another. “Seal” does not refer to a perfect air- or fluid-tight seal. Rather, “seal” refers to shutting out most of the visible light and is to be further defined in the context of the application for which it is to be applied. For example, seal may require points of contact in the context of providing strength to the structure or limiting the risk of food and grease getting caught in the corner and inner portion of the bend line. In the case of fluid-tight structures, “seal” will refer to sealing out a particular fluid.

One will understand that the overlap structure may be modified and utilized in other aspects of the resulting three-dimensional structure. For example, bottom 249 may be formed from a sheet of material with an overlap structure. The overlap structure may be configured as a flange to engage the housing for increased stability or to engage mounts 267. The overlap structure may be formed by alignment of portions of sheets without a bend line. As shown for example in FIGS. 13H, pre-formed bend angle flanges on separate sheets may align with each other without the use of a bend line. Various aspects of the present invention as shown and described may be modified to achieve lower cost and/or increased performance and flexibility.

The structure of the present invention provides several advantages in comparison to conventional sheets of material with multiple, overlapping folds. As shown in FIGS. 13A-13G and 14, the overlap structure isolates bend line 279 at a remote location from an interior volume 288 of the oven. The overlap structure also provides the benefits of folding techniques while retaining a sealed corner 289 of the oven compartment. Thus, even if coatings or other treatments are not applied to the bend line, the benefits remain with respect to the functional part of the oven, in particular, the inner cooking surfaces of the oven compartment.

The overlap structure described may also be utilized in various other applications aside from appliances and cooking ranges. For example, the structure may be modified for application including, but not limited to, the formation of electronic component chassis, automotive components and chassis, transport components and chassis, construction components and chassis, and more.

The method of making oven compartment 240 and housing 239 will now be briefly described. The complete manufacture of the exemplary cooking range will not be described in detail. For example, the manufacture of the stove top subassembly and assembly to the cooking range will not be described. Instead, the following discussion is intended to illustrate to one skilled in the art the structure and method of the present invention and how it relates to other techniques for the manufacture of the overall product.

As described above, the oven body may be formed from a single sheet of material folded along a plurality of bend lines as described above. Although shown as separate panels, the housing may likewise be formed from a folded sheet of material. Because the three-dimensional structure, including the oven compartment, may be formed from one or more folded sheets of material, the sheets can be treated prior to folding. For example, a non-stick coating may be applied to the sheet before assembly. In contrast to conventional assembly processes which involve many moving parts, complicated systems, and attachment of various components, the method of forming a structure of the present invention is simple and utilizes fewer parts and moving machinery. Thus, there is less likelihood of the surface being nicked, chipped, or dented.

Housing 239 provides the core skeletal structure of range 230. The housing includes a back panel structure 291 and side panels 293. The side panels form the cosmetic exterior of the structure in addition to providing necessary rigidity.

The housing houses or encloses oven body 247 (shown in FIG. 7). In various embodiments, the oven body is positioned in the housing such that bend line 279 is positioned adjacent to the corner of the housing (e.g. FIG. 13C). The positioning of the sheet in the crook of the housing corner and rigid angle flanges mutually reinforces the oven body and housing. In this manner, the housing and inner structure are engaged or locked such that side-to-side movement imposes a compressive force on the sheet of material and oven compartment. The configuration of the oven compartment and housing thus acts as cross-brace to impart additional rigidity to the system.

Referring to FIGS. 15-16, back 291 generally has a rectangular cross-section and provides a stand-off between the rear end of the working components of the range and the wall against which it will be placed. The electrical system, gas or electrical connection, and other components utilize the space provided by the back panel structure.

Back panel structure 291 acts as the backbone of the housing. Back panel includes a plurality of thin walls forming hollow sections. The back structure includes various flanges, corners, tabs, and the like to increase rigidity and provide access to the interior volume. In various embodiments, each side of the back panel structure includes posts 295 formed by a hollow volume defined by thin wall sections 296.

The back panel structure is formed from a sheet of material bent along a plurality of bend lines to form various wall sections. The bend lines are positioned and configured such that the bent sheet of material defines a predetermined cross-section of posts 295. Using the precision bending techniques described in the above referenced patents, the sheet of material may be prepared for precision bending to precisely control the final shape of the structure. The sheet of material may be prepared with bend-controlling displacements, such as slits or grooves, to facilitate and control bending. In this manner, the back panel can be precisely formed to match with the rest of range structure 230 and perform its necessary function.

The sheet of material forming the back panel structure includes at least one bend line defining a fold-out tab portion (e.g. FIG. 15). The fold-out tab portion is formed in one of the walls of the bent structure such that it folds down into the predetermined cross-section or interior volume of the post. The tab has a peripheral shape complementary to the predetermined cross-section of the post.

When the tab is folded into the post interior, at least one side engages or becomes proximate an immediately adjacent wall. Thus, the tab nests within the post and defines in part the cross-section by providing a stop or resistance to movement of the wall. As force is transmitted through the range, the post structures will want to move but will be limited by the tab. Any movement of the posts will apply a compressive force on the tab which will in turn apply an opposite force thus limiting movement. In this manner, the tab acts as a cross-brace for the posts. As would be understood by one skilled in the art from the foregoing, the tab may define the shape of the post wall structure by engaging at least one wall and may brace the structure by engaging at least two walls. In various embodiments, the tab is configured to “matchbox” the wall structure.

The tab and post structure may be modified as will be understood by one skilled in the art. The tab may be dimensioned to correspond with the dimensions of the post cross-section to create an interference fit whereby the tab abuts the inner wall surfaces. Alternatively, the tab may be disposed inside the post such that all or a portion of the periphery is merely adjacent the walls. The tab may also be configured to engage or secure to one of the walls of the post. For example, the tab may be held in place by “snapping” into the space defined by the walls. The tab may also be fastened to the walls using other fastener-less configurations or fasteners including, but not limited to, hooks, tab-in- slot, snaps, adhesives, rivets, and the like. Although shown folded down to an angle substantially orthogonal from the post walls, the tab may be folded down in various fashion depending on the post configuration.

Similar tabs and flanges may be provided through range structure 230. Fold-out tabs may be provided in back panel structure 291 to secure the structure to the oven compartment and/or housing side panels. For example, the tabs may be configured to provide an attachment point for fasteners on the side panels. The tabs may also be provided secure adjacent panels or components together enhance structural rigidity or to aid in assembly of components.

The three-dimensional structure may be formed by a variety of processes. Referring to FIGS. 17A-17J, in various embodiments, the three-dimensional structure is formed from a coil stock of material 275b′. The coil is unrolled into a long sheet of material 275b.

In various embodiments, sheet 275b may be treated or processed before being wound into the coil. For example, the material may be treated with a coating, such as a non-stick coating. The sheet may be treated at various stages in the process or after final assembly of the three-dimensional structure, meaning, during a finishing step.

The sheet is fed through machinery configured to form features in the sheet of material as it is fed. Such features include bend-facilitating structures 274b. Other features may be formed in the sheet depending on the application and manufacturing requirements. For example, mounting structures, apertures, tabs, shelves, and the like may be formed in the sheet material. The features may be formed by stamping with lances, punches, draw processes, and the like. The features may be formed in the sheet of material in a transverse direction in one or more steps as the sheet of material is fed. Components may also be attached to the sheet in situ.

Other features may be added to the sheet upstream as it is unwound from the coil stock. Such features include, but are not limited to, functional components and subassemblies. The features may be added using adhesives, welding, fasteners, and similar processes.

After forming the bend-facilitating structures in sheet 275b, the sheet may be subjected to roll forming up or down the line. Referring to sequence (A) through (E) in FIG. 13A, the sheet may be subjected to hits to produce successive bending along bend lines in a longitudinal direction. The bends may be done gradually or in stages. Bending may be performed along bend lines sequentially or in parallel fashion. The roll forming may also be performed in any order with the forming of features in the sheet.

The process includes severing the sheet of material from the coil stock before or after the forming of one or more features. The sheet may be rough cut and later finished. The sheet may also be precisely cut thereby producing a finished product in a single step.

As will be understood from the above, the process described allows for fast and efficient processing. A stock coil of material may be fed through a simple, modified assembly to form a sheet product 310′ in a reduced number of steps. As shown in FIGS. 17B-17C, some of the bending may be performed on the line before cutting. The resulting product may then be formed by further bending of the product along the bend lines. Thus, the sheet can be prepared and bent into a 3D structure with a few simple stations.

Turning to FIGS. 13 and 17, various components and subassemblies may be fabricated separately from several sheets. In various embodiments, a panel 312′ is formed for insertion into the resulting three-dimensional structure. Panel 312′ may be configured similar to bottom 249 described above such that it may be adjustably positioned within the appliance compartment to be formed. The panel includes an outer lip or flange 314 that extends around the periphery of the panel. One will appreciate that the flange may also be formed as an overlap structure similar to that described above. Sheet 275b includes a corresponding lip feature 88, which can be formed in the sheet by the above process.

As the sheet is bent long the bend lines, an overlap structure 281b is formed at the comers (shown in FIG. 17F). The sheet further wraps panel 312′. The panel is secured inside the bent structure by fastening lip 314′ to corresponding lip 316′ on what becomes the interior wall (shown in FIG. 17F). A number of panels may be provided within the bent structure to modify the layout and configuration of the three-dimensional structure to be formed.

Referring to FIGS. 17I-17J, a three-dimensional structure may be formed by bending the sheet product along bend lines. Thereafter, additional features may be added and the structure may be finished. In various embodiments, mounting brackets are added to the bent structure to brace the structure and provide a mounting surface for doors. Feet, labels, insulation, wiring, and other features and assemblies are further added during finishing.

One will understand that the process described may be modified depending on the application. The order of various steps may be modified. The manner in which features and events in the sheet are formed may be modified and/or performed with different processes. The dimensions of the three- dimensional product to be formed may also be easily modified by changing the width of the stock coil material and/or the shape and location and timing of the severing, slitting, or punching of the sheet. Other modifications and variations are envisioned within the scope of the invention.

Turning now to FIG. 18 an exemplary folded, three-dimensional structure, generally designated 30, is shown in accordance with some aspects of the present invention. The exemplary structure 30 may be modified for integration with the exemplary range appliance described above or as a separate appliance. In some respects, structure 30 is similar to structure 230 above.

In one exemplary embodiment, three-dimensional structure 30 is a housing structure with a hinged cover, for example, an appliance, such as an oven, a dishwasher, a washing machine, or a dryer; a container, such as a safe, a toolbox, or a cabinet; or an enclosure.

An exemplary oven is generally formed from two dimensional sheet members, some of which may be pre-assembled components and others of which may be assembled on-site. FIG. 21A through FIG. 21P illustrate an exemplary method of forming a three-dimensional structure in accordance with various aspects of the present invention. By contrast to the process of forming structure 230 described above and illustrated in FIG. 17, the method of forming exemplary structure 30 allows for shipping parts in-the-flat and assembling remotely. The process described below also calls for greater interrelation of parts and more manual labor in the process; however, one will appreciate that the processes of the present inventions may be modified depending on the application.

An optional workbench 32, described in more detail below, provides a stable platform for folding and forming the various subparts of the three-dimensional structure. In an exemplary embodiment, the workbench has extensions in three directions to provide a working surface for forming sides of the oven. As the front of the oven includes an oven door, instrumentation, and the like, these components may be pre-assembled as sub-assemblies at another location and affixed to the housing structure during assembly. However, these components may also be assembled using similar methods to those described herein. In fact, most, if not all, of the oven's structural components and body may be formed by bending sheets of material prepared in accordance with the principles described herein and using methods such as the ones disclosed by the above-mentioned '934 and '216 applications.

With reference to FIG. 18, an exemplary three-dimensional structure in the form of an inner oven chamber includes a substantially box-like inner core structure 33 formed from one or more two- dimensional sheets of material 35. In the exemplary embodiment, the inner structure 33 is formed of five sheets, however, one will appreciate that the inner structure may be formed of one, two, three or more sheets of material. As will be described below, each sheet of material may be a rigid member with no bend lines or may have one or bend lines 37 to facilitate bending into a three-dimensional structure to form the inner structure. In the alternative, the inner structure may be an integrally pre- formed three-dimensional structure.

The inner structure is positioned within a housing 39, which is also formed from one or more two-dimensional sheets of material 40 folded into a three-dimensional structures. Sheets of material 40 may also be configured for bending along a plurality of bend lines 42 in a manner similar to the above-mentioned sheets. The plurality of bend lines further define sides or panels 44 and contours of the housing. In an exemplary embodiment, each side 44 forms a substantially planar face of the housing structure (see, e.g., FIG. 24), however, one will appreciate that the other shapes and structures may be defined. For example, the sheets may be stamped with ribbing and/or other structural features and/or ornamental details that may strengthen, facilitate assembly, and/or otherwise improve structural integrity or aesthetics.

The bend lines of the inner structure and the housing include a plurality of positioning structures 46 to facilitate and dictate the location of bending of one outer side relative to another outer side along one or more bend lines. In one exemplary embodiment, at least one positioning structure 46a on a first panel portion 47a is configured to nest within another positioning structure 46a on second panel portion 49b such that the panel portions lay flat along the outside of the housing.

In one embodiment, the positioning structures 46 are formed on one or both of the housing and the inner structure and/or any number of other components to be transported in-the-flat and thereafter folded into a three-dimensional structure, that is, in a substantially two-dimensional state and later folded into a three-dimensional structure. In an exemplary embodiment, a plurality of bend-inducing structures are formed in the thickness direction of sheets 35 and 40.

In an exemplary embodiment, the sheets of material forming the housing includes peripheral flange portions 53 along respective bend lines 42 extending along panel portions 54 of the sheet of material. The bend lines extend along the periphery of the panel portions to form the peripheral flange portions. As best seen in FIG. 21G, the peripheral flange portions include outer tabs or flaps along panel portions 54. In an exemplary embodiment, the peripheral flange portions extend from the bend lines defining the outer perimeter of the panels. During the bending process, the peripheral flanges are bent along respective bend lines before the panel portions are folded.

The peripheral flanges serve several purposes. As shown in FIG. 21M through FIG. 210, peripheral flanges 53 provide a portion of the sheet to couple together housing 39 when folding around inner structure 33. The peripheral flanges also overlap each other along edges 51 of the housing such that the edges and comers of the housing have multiple layers of the sheet. For example, when the peripheral flange and a respective panel portion 54 fold over another panel side 54b of the housing, the peripheral flange will overlap a portion of this adjacent panel 54b and create a two-sheet-thick framework (see, e.g., FIG. 23A). Thus, each peripheral flange portion and a respective panel cup the bend line of another panel or peripheral flange with a double thickness framework. The edges and comers of the structures generally carry a significant load of the structure; thus, the above configuration allows for additional material thickness in the key load-bearing portions of the structures. In this manner, an exemplary housing structure has a skeletal framework along the edges and comers with increased material thickness and strength without increasing the total thickness of the entire structure.

In the exemplary embodiment shown in FIG. 23A, the sheet of material includes a first peripheral flange portion 53a along a first of the bend lines overlapping a first panel portion 54a of the sheet of material, and a second peripheral flange 53b portion along a second of the bend lines overlapping a second panel portion 54b of the sheet of material. The peripheral flanges and panels thus form a framework 56 of additional thickness along the edges of the housing for additional support. In an exemplary embodiment, a framework two-sheets-thick runs along a periphery of the three-dimensional structure and thus defines load-bearing framework.

Referring back to FIG. 21H to FIG. 21L, the inner structure may include one or more support flanges 58 extending outward from a periphery thereof which are configured to engage with the housing. The inner structure is placed within the housing in a wrapping arrangement, as shown in FIG. 21L to FIG. 21P and FIG. 23A to FIG. 24. Each support flange extends towards a respective bend line 42 of the housing. In the case where inner structure 33 includes bend lines, the support flange extends from an inner structure towards framework 56 of housing 39.

Turning to FIGS. 21-23, the inner structure includes an inner skeletal structure 60 formed along the periphery of the inner structure. The inner skeletal structure is formed by the combination of inner edges 61, inner structure flanges 58, and the corners of the inner structure. The inner structure edges and flanges are joined together along the periphery of the inner structure at corners or vertexes. In an exemplary inner structure, the flanges overlap each other. Each flange extends from a respective inner structure edge towards a bend line of the housing. Depending on the particular overlap configuration, the overlapping flanges are fastened to each other, the inner structure, or the panels of the housing. The flange thus braces inner skeletal structure 60 against movement. In this manner, the inner structure is supported by the flanges and vice versa in a “matchbox” fashion.

Additionally, when the inner structure is positioned inside the housing, the inner skeletal structure and housing may mutually reinforce each other. Referring to FIG. 23A, a first end of each flange 58 extends into a crease or crook 63 formed by a respective bend line of the housing. An opposite end of each flange extends diagonally from the bend line to a corner or edge of the inner structure such that the bend in the housing is supported by the inner structure through the flanges. In one embodiment, at least two of the plurality of flanges extend from opposite sides of the inner structure such that they are diametrically opposed. In an exemplary embodiment, at least one flange is substantially straight. In this manner, the housing and inner structure are locked such that movement of sides 44 and bend lines 42 of the housing imposes a compressive force on respective flanges 58 and inner structure 33.

Referring back to FIG. 13, the bent sheet may be matchboxed inside the housing in similar manner. As will be understood by the above description, the configuration of the inner structure flanges, and housing may be modified depending on the application. The inner structure may have any number of edges depending on the three-dimensional structure to be formed. The number and configuration of the flanges may be modified. For example, the inner structure may have a bulbous or curvilinear portion on the inside of a bend line or edge of the housing. In this instance, a flange may be configured such that it circumnavigates and substantially conforms to the surface of the inner structure and extends to the housing bend line. In another example, the flange may not extend exactly from inner structure edge to housing bend line. Instead, the flange may be configured to fasten to a portion of each respective structure adjacent to or even remote from the respective edges. Such a configuration may be desirable when another component is to be placed in the comers or edges or some other design limitation requires the flange mounting point to be moved.

Referring back to FIGS. 21-23, in one embodiment, each support flange includes a fastening structure 65 on an outer edge 67 thereof to fasten the flange to the housing thereby securing the inner structure to the housing and maintaining engagement between the flange and respective bend line (see, e.g., FIG. 27). The fastening structure of each inner structure support flange cooperates with a respective positioning structure of housing 39 to support inner structure 33 within the housing.

In one embodiment, the fastening structure has a tab and slot configuration. Fastening structure 65 includes a tab 68 and a respective slot or aperture 70 along a respective bend line 42 or crook 63 of the housing. Preferably, fastening structure 65 is monolithically formed with the respective sheets of material, as is the case with an exemplary embodiment. During or subsequent to folding, the tab may be inserted into the aperture thereby engaging a respective support flange of the inner structure to a portion of the housing. As can be seen in the figures, a plurality of fastening structures are provided to engage each lateral corner of the inner structure with a respective corner of the housing spatially affixing the inner structure to the housing.

In this embodiment, each support flange is fastened to the housing without a discrete fastening structure. Instead, flange 58 locks into crook 63 of the bend line during assembly of the three-dimensional structure as tab 68 engages with corresponding aperture 70. Alternatively, the flange may not extend at all into the crook of the respective bend line and/or may include an intermediate structure to engage with the housing.

The flange may be fastened to or formed with one of the housing or the inner structure as described above. Alternatively, the flange may be freely placed between the inner structure and housing. For example, one of the inner structure or housing may employ an alignment structure to align the flange during the bending of the housing. Once the housing is formed, the flange may be held in place in the crook of the respective bend line.

Other fastening structures may be also be utilized including, but not limited to, those described in the above-mentioned '440 application. Such fastening structures include, but are not limited to, tie mounts, snaps, screws, and the like.

Further, the structure, dimensions, and configurations of the flanges may vary depending on the application. In one embodiment, at least one flange extends from the inner structure to the housing at an acute angle from a plane defined by an inner side 72 of inner structure 33. In one embodiment, at least one flange extends at substantially 45 degrees from the plane. Other configurations include, but are not limited to, dimensioning and shaping flange 58 for a particular application. For example, the flange may have a length determined to provide a stop for movement of the bend line of the housing or may be configured to provide a spring force or “give” to the overall three-dimensional structure. Because each flange effectively guides or restricts movement of a respective bend line, the flange may be configured in various manners to control the overall rigidity and movement of three-dimensional structure 30. Moreover, more than one flange, in particular those on opposite comers of the inner structure, may be configured to work together to influence and control physical characteristics of the three-dimensional structure.

When housing 39 is wrapped around inner structure 33, the inner structure imparts strength and rigidity to the housing and vice versa. In one embodiment, the housing is a loosely-formed structure with minimal strength independently. The inner structure and flanges impart strength to the housing structure and overall three-dimensional structure. In particular, the flange secures and supports a respective bend line of the housing. In one embodiment, neither the housing nor the inner structure have significant strength independent of one another. One will appreciate that inner structure 33, flanges 58, and housing 39 can be arranged in various ways to increase the rigidity and strength of the resulting three-dimensional structure. In an exemplary embodiment, the inner structure and flanges form a type of cross-bracing within the housing whereby the inner structure forming the oven box mutually reinforces the oven housing.

Similar to the housing, inner structure 33 may be formed from at least one inner sheet of material 35b including an inner bend line 74b. In one embodiment, support flange 58 is monolithically formed with the at least one inner sheet and the inner bend line defines a border between at least one of the support flanges and inner side 72. As shown in FIG. 22, the flange is thus formed by overlapping panels on the sheet of material during folding of the inner structure. The inner bend lines define a border between the inner side and the support flanges.

In one embodiment, the housing sheet of material 40 and at least one of the support flanges are monolithically formed. In one embodiment, one of the housing and inner structure sheets of material includes a lip portion 75. In the case where the lip extends from the housing, bend line 42 of the sheet of material defines a border between a side panel 54 and the lip portion. The lip portion extends towards the inner structure in a direction substantially parallel to the flange portion. In one embodiment, the inner structure is formed from at least two sheets of material, one of which includes a bend line. The lip portion extends from the bend line such that it aids in locating an end of the flange to the edge or bend line of the inner structure. The lip portion may be fastened to at least one of support flanges 58 using a fastener. Alternatively, the lip portion may fasten to the respective flange without discrete fasteners. The lip portion is configured to provide additional support to three- dimensional structure 30 and strengthen fastening of the flanges 58 between the inner structure and housing. The lip also serves as a mounting point for the flanges.

The housing may be configured for a variety of applications. The housing in the exemplary embodiment is configured to act as an oven housing. As such, the housing is configured for mounting a modular control panel 77 thereto. The housing further includes at least one aperture 79 providing a guide path for electrical wiring and mounting points for an oven door. The housing may be configured in other ways as will be understood by one skilled in the art whether forming an appliance or any other three-dimensional structure. Similar configurations for electrical wiring and the like are described in the above-mentioned '440 application. As will be described below, application-specific configurations may be made at any stage in the process of forming the three-dimensional structure from the preparation of the sheet of material to the finishing process after the sheets of material are folded.

Suitable materials for the housing and/or inner structure include, but are not limited to metals, plastics, and other materials. In one embodiment, the inner structure and/or housing are formed from a sheet of material that is relatively incompressible and rigid. Thus, conventional paper and paperboard products are not considered incompressible. In an exemplary embodiment, the housing and inner structure are stainless steel. Similar materials may be used for the flanges. A variety of materials may be used depending on whether the application necessitates strength, rigidity, chemical inertness, corrosion resistance, and the like.

An exemplary method of manufacture of a three-dimensional structure in accordance with various aspects of the present invention can now be described. Referring to FIG. 21A to FIG. 21P, an assembly system is shown in accordance with the present invention. The component parts of the oven may be manufactured at an otherwise conventional first station or forming area including metal- forming equipment. In particular, sheet of material 40 may be prepared with monolithic positioning structures and fastening structures in accordance with the above description. As noted above, the positioning structures may be formed with processes similar to those described in the above-mentioned '450 patent and with reference to FIG. 17 above.

Additionally, other basic parts, whether plastic, natural materials, or otherwise, may also be prepared in the forming area. In an exemplary embodiment, the oven structure body is composed primarily of steel sheets prepared for bending. The forming station therefore includes machining equipment to cut multiple sheets and prepare a plurality of bend-inducing structures. For example, a CNC machine may be used to prepare the bend-inducing structures. The outer dimensions of the sheet of material are also important and may be prepared with similar equipment. The sides 72 of the inner structure may also be prepared in this station or at another location. One will appreciate that such steps may be prepared on one or more stations.

The forming station may be remotely located from the area in which the rest of the manufacturing process is performed. In particular, the sheet of material forming the housing, whether a single sheet or multiple sheets configured to be joined together, may be formed at one location and transported to another location in-the-flat. In one embodiment, the positioning structures of each sheet are configured to receive positioning structures in adjacent sheets of material whereby the sheet of material may stacked flat with the adjacent sheet of material. Thus, when the sheets of material are stacked on top of each other, positioning structures in one sheet nest in the positioning structures of adjacent sheets. This allows for a reduction in packing size when shipping the sheets of material in the flat for folding at a remote location.

Referring to FIG. 21A to FIG. 21P, the housing may be formed from a single sheet of material or multiple sheets of material thereafter joined together. In an exemplary embodiment, the housing is formed from a two-dimensional sheet of material 40 formed from three separately-formed sections 40′.

A first section 40a is placed on workbench 32, and peripheral flanges 53 are folded up around the edges. The first section includes what will become a first side panel 54a and bottom 81 of the housing.

Next, a second section 40b is laid on the workbench in an area adjacent to the first panel. The second section includes what will become a second side panel 54b and top 82 of the housing. The peripheral flanges of the second panel are then folded into position.

Finally, a third section 40c is laid on the workbench. The third section overlaps a portion of the first section. In an exemplary embodiment, the peripheral flanges on the first and third sections are laid over each other and folded to form a mounting point for flange 58 (see, e.g., FIG. 21G). In particular, the two sections may be joined together to form an edge flange portion 84. The other peripheral flanges on the third section are then folded up. These steps are repeated until all the sheets of material are positioned on the workbench with the peripheral flanges folded.

After the sections of the sheet of material are in place and prepared, they are joined together by fastener structures. A variety of structures may be utilized. In an exemplary embodiment, the fastener structures are similar to those described above including, but not limited to, tab-and-slot fasteners, screws, tongue-and-groove fasteners, and the like. Fastening structures also include welding, adhesives, and the like. In an exemplary embodiment, rivets are used to further secure the panels together into a single sheet of material see, e.g., FIG. 21G).

Once the housing sheet of material 40 is prepared, the inner structure may be assembled. Referring to FIG. 21H to FIG. 21M, the inner structure is assembled on the housing. A first side portion 72a of the inner structure is fastened to sheet of material 40. The side portion includes flange 58 at a far edge which is fastened to the lip of the housing. (see, e.g., FIG. 21H). As shown in FIG. 21I, the side portion is then folded up to a position perpendicular to the sheet of material, and in particular, the bottom portion.

Next, the other side portions 72b and 72c are affixed to the sheet of material and the first side portion. The three sides form a cavity of the inner structure, which will become the over box in an exemplary embodiment. Thereafter, a top side 72d is positioned on top of the side portions and fastened thereto. In an exemplary embodiment, the top side includes three flanges 58′ which overlap flanges 58″ on each of the side portions 72a, 72b, and 72c. Thus, the flanges have double-thickness. As can be seen in the drawings, the flanges extend from a periphery of the inner structure along the edges from corner-to-corner. The increased-thickness flanges and comers of the inner structure form inner skeletal structure 60.

After the inner structure walls are formed as described, a front face 86 is affixed to the inner structure. The front face provides mounting points for various components. In an exemplary embodiment, the face includes mounting points for the oven door. A control plate 88 is further provided for mounting of a control or display module 89. The front face may also be configured to increase the stiffness of the inner structure. As will be understood by one skilled in the art, the front face of an exemplary embodiment forms a wide frame that serves to increase the stability of the inner structure. The strengthened flanges, attachment configuration to the housing, and front face all provide for a robust and high-strength inner structure.

The inner structure assembly may be performed at the same location or another location remote from the housing assembly area. In an exemplary embodiment, the inner structure is formed by a plurality of panel portions or sides 72 joined together. In an exemplary embodiment, the inner structure includes an overlapping structure 91, such as winged flanges, along the periphery or edges which form a type of skeletal structure (see, e.g., FIG. 23A). Because of the overlapping material, this skeletal structure has increased rigidity and strength. In the alternative, the inner structure may be formed by conventional methods such as welding sheets of material. In one embodiment, the inner structure is formed from a two-dimensional sheet of material similar to the housing.

In other embodiments, the overlapping structure 91 may be fastened together with discrete fasteners (see, e.g., FIG. 23B), or be a unitary sheet over upon itself (see, e.g., FIG. 23C, FIG. 23D). Also, the angle at which the overlapping structure may vary, see, e.g., FIG. 23C).

Also, tabs 73 may be provided at the extremity of flanges 58 which are adapted to extend into and engage apertures 73′ in the housing. Such configuration allows the for-and-aft position of the inner structure to be affixed relative to the housing (see, e.g., FIG. 23B).

Flanges 58 may also be formed before transporting the prepared components and sheets. The flanges may be formed at the forming station or at another location. The flanges may also be monolithically formed with the inner structure or housing. After the inner structure is positioned on the housing panels, the flanges are fastened to the inner structure. Each flange is fastened such that it extends from inner structure 33 to a respective bend line of the housing. In an exemplary embodiment, each flange extends from an inner edge of the inner structure into the crease formed by the bend line of the housing.

A plurality of edge flange portions 84 may also be provided on the housing as described above to strengthen the flange structures. The edge flange portion is a portion of material that extends in substantially the same direction as a respective flange 58 and resides on an opposite end of the respective flange from lip 75. The edge flange portions perform a similar function as the lips.

Similar to the lips and inner structure flanges, the edge flange portions may be monolithically formed with the housing or separately formed and fastened. In one embodiment where the edge flanges are monolithically formed with sheet of material 40, the sheet has additional bend lines and panels to form the edge flange portions in an accordion-like fashion. A side of the housing is bent along a bend line. Next, a first side of an edge flange portion is folded and then a second side of the same edge flange portion is folded back along and overlaps the first side. In this manner, the edge flange portions have a thickness equal to two sheets and lend additional strength to the housing and the end of the attached flange. If the edge flange portions are defined by bend lines with displacements, the bend-controlling displacements defining a bend line of the first edge flange portion may be configured to nest within the displacements defining a bend line of the second edge flange portion. Flanges 58 and lips 75 may also be formed in the same manner such that the entire oven box and housing may be formed from a few sheets of material.

Referring to FIG. 21A to FIG. 21P, a second station 93 is provided to facilitate bending the sheets of material into three-dimensions. In one embodiment, the bend station includes workbench 32. After preparing the sheets of material in the forming area, the sheet intended to form the housing is placed on the workbench and the three-dimensional structure is formed by bending the sheet.

Second section 40b is folded about a first bend line and then about a second bend line until the second section wraps about the back of the inner structure (see, e.g., FIGS. 21M-21N). Once folded around the inner structure, the peripheral flanges wrap around edges of the inner structure such that the peripheral flanges overlap a portion of the inner structure sides. In an exemplary embodiment, as the sheet of material is folded, both of the bend lines engage the edges of the inner structure. Specifically, the bend lines engage the ends of flanges 58. Next, the other sections of the sheet of material are folded around the inner structure in a similar manner until the housing is formed. In this manner, the housing is formed around the inner structure to form a rigid three-dimensional structure.

Further, in an exemplary embodiment, the housing and inner structure are formed and configured such that each flange extends from a bend of the housing to an adjacent edge of the inner structure. A flange extends from each edge of the inner structure such that, when viewed in a direction orthogonal to the sides of the structure, flanges on opposite edges extend in the same direction, and in particular, through a diagonal of the inner structure from border-to-border (see, e.g., FIG. 26).

As best seen in FIG. 28, workbench 32 may be configured to promote bending of the sheets of material into three-dimensional structures and assembly of the finished product. In an exemplary embodiment, the workbench includes hinged flaps corresponding to faces of the structure. The bend lines of the hinges correspond to the bend lines in the housing such that when the flap is rotated the sheet of material is precisely folded along the bend line. The flap further provides the user additional leverage during bending and minimizes contact between the workpiece and workbench. This protects the user's hands from being scratched or cut by the workpiece and can also reduce smudges and dirt on the workpiece from the user's hands. The workbench may also be configured similar to that described in U.S. Patent Publication No. 2006/0053857 to Durney (which is hereby incorporated in its entirety by reference) for most flexible manufacturing and precise bending of the sheets of material.

Further, workbench 32 may be configured for flat-shipping and assembly in remote location much like the three-dimensional structure. In an exemplary embodiment, the workbench is formed from flat pieces of material that are joined together at the assembly site. The individual pieces may be fastened with known fasteners or can be pre-joined with hinges or the like to allow folding into the sturdy, three-dimensional shape shown in the figure. Configurations other than those described may be used depending on the application.

The sheet of material and inner structure are placed and aligned on the workbench. The inner structure formed in the first station is positioned on the sheet of material such that fastening structure 65 engages or aligns with positioning structure 46. The sheet of material is then bent along the bend lines into the three-dimensional housing. The inner structure remains positioned therein such that the housing is wrapped around the inner structure. The housing may then be coupled to retain it in the bent position. The housing may be coupled by fasteners and the like formed integrally with the sheet or separately formed.

In the bent position, the fastening structure supports the inner structure relative to the outer housing structure. The flanges may be configured as braces for both the inner structure and housing such that the two structures mutually support each other. For example, in an exemplary embodiment, the flanges are configured to act as cross beams with the inner structure inside the housing. In turn, the flanges also support and hold the position of the inner structure edges.

During the bending process, other components may be added to the structure. For example, the oven heating element may be added before or after sheet of material 40 is folded. The door for the oven may also be added at this station after the bending process is completed.

In one embodiment, the edges of the housing are formed with more than a two-sheet-thick framework. In this embodiment, a first peripheral flange portion overlaps a portion of a second panel portion sheet and the second peripheral flange portion overlaps a portion of the first panel portion. As seen in FIG. 21M, a first bend defining the first peripheral flange is immediately adjacent and parallel to a second bend line defining the second peripheral flange. This results in a two-sheet-thick framework formed by the overlap of the first and second peripheral flange portions along a periphery of the three-dimensional structure. Further, the flange portions form a three or more sheet thick framework when folded over respective panel portions in this manner. This may be compounded with three, four, and more peripheral flanges and portions of the sheet of material.

From bending station 93, the structure moves to a fit-and-finishing station 95. In this finishing station, the structure is converted from a bare-bones structure to a final and complete product, in this case an oven. In an exemplary embodiment, a variety of subassemblies are affixed to the oven body. Such subassemblies include electrical wiring, control panels, heating subassemblies, and the like. If the oven includes an optional stove top, a preassembled stovetop assembly may be fastened to the top of the oven body in this station. Likewise, if the door has not been fastened to the structure yet, it may be fastened at the bending station. As will be understood by one skilled in the art, several other functions may be performed at the finishing station or bending station including, but not limited to, installing wiring and tubing, adding decorative panels, adding trim and decorative plates, and the like. These functions may also be done at earlier points in the manufacturing process.

With reference to FIG. 21K, it is noted that many components may be installed within the interior of the oven cavity at this stage. And with reference to FIG. 21L, many components may be installed to the exterior of the oven cavity at this stage of assembly. One will appreciate that the assembly sequence allows the installation of various components and subassemblies during various stages of overall assembly. Moreover, one will appreciate that many fasteners, components and/or subassemblies may be stored under the table and/or on shelves thereon and are thus readily accessible to the assemblers. With reference to FIG. 4P, one will also appreciate that many components and/or subassemblies may be added to the assembly by pre-attachment. For example, a control panel subassembly may be added to the assembly.

The three-dimensional structure may also be formed from a sheet of material in accordance with the present invention such that that many of the typical finishing process are not necessary. For example, nameplates may be replaced by stamping items directly into the sheet of material in the forming station. Paint may also be applied to the sheet of material after forming instead of painting the finished three-dimensional structure at the end of the manufacturing process. In many cases, such flexibility allows for opportunities to reduce manufacturing costs and increase efficiency.

In another exemplary embodiment of the present invention, inner structure 33a is similar to inner structure 33 described above but includes is formed of two sheets of material instead of five, as shown in FIG. 29A through FIG. 29D. Like reference numerals have been used to describe like components of inner structure 33 and inner structure 33a. In this embodiment, four inner sides 72a are monolithically formed from a single sheet of material and interconnected by flanges 58a which are configured to fold back upon themselves (see, e.g., FIG. 29A). One will appreciate that the geometric layout of interconnected structure 93 is particularly well suited for nesting and shipping in-the-flat.

This embodiment is particularly well suited for enameling “in-the-flat”, that is, a layer of enamel 97 may be applied to interconnected structure 98 while the structure is substantially two-dimensional and before the structure has been folded. In this embodiment, the layer of enamel may be applied to the entire structure including along and on the “troughs” 99 by dipping, coating or other suitable means. Also, the enamel may be baked or cured “in-the-flat”. Upon folding, the only enamel exposed directly to folding would be directly within the troughs and, as such, if the enameled layer failed (e.g., cracking, breaking, etc.) the area of failure would be within the overlapping portion of flange 58a, isolated from the oven cavity and thus out-of-sight. The overlapping portion may also be modified in accordance with the above description and as shown in FIG. 13.

In various embodiments, the positioning structures are formed with aesthetic factors in consideration. In one embodiment, the positioning structures in the sheet of material forming the housing are all formed on one side of the bend line such that they form a smooth edge when the sheet is bent. Such configurations and modifications are similar to those described in the above-mentioned '216 application and '426 patent.

After the finishing station, the assembly system may also include one or more inspection sites and other quality control/quality assurance (QA/QC) processes. In an exemplary embodiment, the assembly system includes an inspection station (not shown) subsequent to the finishing station.

Several processes may be performed at various stations or off-line as understood from the foregoing discussion. For example, painting, construction of subassemblies, installing wiring and functional equipment, and similar processes may be done at any number of stations. Alternatively, many of the components may be fully prepared at another location and added to the structure somewhere on the assembly line.

As will be understood by one in the art, the assembly system may be configured in many alternative ways. The three-dimensional structure and method of the present invention allow great flexibility in the assembly system. In particular, because the use of tools, skilled labor, and heavy equipment is greatly minimized, the manufacturing system can be configured in ways not possible with conventional methods. For example, the bending station and forming station may be separate and distinct from each other. Additionally, most, if not all, of the assembly system described may be moved out of the factory. In fact, in an exemplary embodiment, workbench 32 and likewise bending station 93 are portable.

Additionally, the exact assembly processes performed to prepare the housing and inner structure depends on the three-dimensional structure design as much as manufacturing constraints. In an exemplary embodiment, the article to be manufactured is an oven with a square housing and square inner structure. Other articles of manufacture may have different design shapes and configurations requiring changing the order and types of process to be performed in keeping with the spirit of the above-described method of manufacture.

The structure and method described has several advantages over conventional structures. The structure and method described allows for precision folding into accurate three-dimensional structures.

Further, structures and methods in accordance with the present invention can have superior strength relative to conventional three-dimensional structures, including those formed from two- dimensional sheets of material. For example, the inner structure and housing can be configured so as to mutually reinforce each other and provide added protection against buckling, collapsing, and wobbling of the resulting structure. Moreover, additional support can be located in selected regions of the structure, for example, along the edges and comers. The structure of the present invention can further provide additional material thickness along the edges of the housing such that a rigid skeletal structure is formed. In this manner, the three-dimensional structure can have superior strength without unnecessary material usage. The structure framework can also have increased resistance to denting and failure.

By contrast to the structures and method of the present invention, conventional assembly processes are more complex and material-intensive. For example, conventional appliances are typically formed by welding thick, heavy-gauge sheets. The sheets must be thick to ensure that the sheets conform to a desired posture for placement in fixtures prior to welding. The sheet and process of the present invention allows for simple assembly of at least semi-independent pieces. Each of the pieces can be easily modified and adjusted. Fixturing problems are reduced or eliminated by the ability to form positioning information in the sheet using the principles described. Further, the components can be more easily mixed and matched with other components. For example, an entirely different appliance series can be manufactured by simply changing the width of the material coil, cutting a different shape, adjusting the timing of the stamping process, and/or adding fewer or more panels in different positions.

As discussed above, application of treatments, finishing and other functions are generally performed with better results and at reduced costs when using sheets in-the-flat in comparison to complex three-dimensional structures. The method of the present invention also reduces capital costs (e.g. tool costs and fewer unique parts), increases flexibility and modularity, and reduces product planning and roll-out times among other benefits. Likewise, energy usage may be decreased in part based on the greater simplicity of the process and reduced use of heavy tools and machinery.

Furthermore, it has been found that the use of relatively thinner sheet material reduces heat flow from the heated compartments. In comparison, conventional appliances typically require heavy stock material for structural strength. Thus, heated compartments not only use less material in accordance with the invention, they also may have better performance characteristics. In cases where increased heat transfer is desirable, apertures and other features may be added to increase the flow of heat. In other words, the thickness of the material to form the structure does not need to be dictated by the strength requirements of the structure. Rather, the structure may be customized for improved performance with less wasted material.

Additionally, other aspects of the structure may be more easily modified for various performance parameters in comparison to conventional structures. For example, the overlap structure described above has been found to reduce heat loss from heated compartments. The amount and configuration of the overlap can be adjusted to reduce the sealing of heat in the compartment.

For convenience in explanation and accurate definition in the appended claims, the terms “up” or “upper”, “down” or “lower”, “inside” and “outside” are used to describe features of the present invention with reference to the positions of such features as displayed in the figures.

In many respects the modifications of the various figures resemble those of preceding modifications and the same reference numerals followed by subscripts “a”, “b”, “c”, and “d” designate corresponding parts.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.

	Number	Date	Country
	61016434	Dec 2007	US
	61102346	Oct 2008	US

HIGH-STRENGTH THREE-DIMENSIONAL STRUCTURE AND METHOD OF MANUFACTURE

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Provisional Applications (2)