METHOD AND APPARATUS FOR FORMING BEND CONTROLLING DISPLACEMENTS IN SHEET MATERIAL

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates, in general, to apparatus for forming bend controlling displacements in sheet material, and methods for their use.

2. Description of Related Art

Various techniques or manufacturing processes for forming slits, grooves, displacements and other means in a wide variety of sheet materials that precisely control bending of the sheet materials are known. Such means include laser cutting, water jet cutting, stamping, punching, molding, casting, stereo lithography, roll forming, machining, chemical-milling, photo-etching and the like. Such means may be applied to numerous structures which are formed from sheet materials. These structures tend to call for complex and precise bending patterns, and the design of these structures requires less emphasis on torsional strength resistance requirements. An example of one type of structure which can be formed from sheet metal and involves precision and complex bending is an electronic component chassis of the type used for computers. Other types of structures may include electrical enclosures, automotive components, transport components, construction components, HVAC components, appliances, airplane components, tracks, audio receivers, television sets, DVD players, and the like.

For example, U.S. Pat. No. 7,152,449 discloses the slitting and/or grooving of sheet materials and mounting electrical components to the flat sheets using “pick-and-place” techniques in which the components are mounted to the flat sheets prior to folding of the sheets. The sheets may then be folded into enclosures or housings in which all of the components are spatially related in the desired positions inside the housing. The “pick-and-place” techniques greatly reduce cost, as does the ability to fold a flat sheet into a precisely dimensioned enclosure using relatively low-force bending techniques. While such electronic chassis can be formed using laser cutting or water jet cutting processes, such processes are typically relatively expensive. Of course, other techniques can be employed either in place of, or in addition to, the foregoing. Such other processes include displacement-forming techniques such as punching, stamping, roll-forming and the like. The displacement-forming processes are well suited for use with sheet materials and are typically, but not necessarily, relatively less expensive than the cutting processes.

A machine press may be utilized to produce displacements in the sheet materials. For example, turret presses and other soft-tooling means are generally conducive to relatively low-volume production including prototyping and other lower volume applications. Relatively high production is often configured with stamping presses and other means, that is, tooling that is specifically designed for and dedicated to the production of a specific part or parts. In either case, the machine press includes tooling that includes one or more male punches with one or more corresponding female dies. The punch and die sets of such tooling are often formed of hardened steel or other hardened metals that are relatively expensive to fabricate. Furthermore, repeated use of the machine press leads to normal wear and tear which may dull the punches and dies relatively quickly. In turn, the precision of the machine press decreases which leads to punched parts of lesser quality. Dull punches and dies may also wear out in terms of alignment and further lead to “dull” parts, that is, parts in which the finished geometry and dimensions are less precise than the desired or designed geometry and dimensions. The punches and dies may be sharpened, however, such sharpening is generally expensive and time consuming, which may leads to down time of the machine press further contributing to increased expense and decreased throughput.

The manufacture of complex structures in sheets of material for bending requires similarly complex systems and processes, which in turns tends to result in higher tooling costs. In the case of preparing sheets with myriad structures and features, the manufacturing complexity can increase significantly. Conventional techniques call for manufacturing relatively simple features with one tool and using another tools for other features.

Further, hard tools which are generally used for faster and higher-volume manufacture tend to be more costly to fabricate and are far less flexible in comparison to soft tools. As such, conventional hard-tooling techniques tend to require a compromise in cost and flexibility, while soft-tooling techniques tend to require a comprise in manufacturing time and lower-volume manufacturing.

In light of the foregoing, it would be beneficial to have methods and apparatuses which overcome the above and other disadvantages of known machine presses. Moreover, there is an ongoing need for further reduction in manufacturing and tooling costs.

BRIEF SUMMARY OF THE INVENTION

One aspect of the present invention is directed to a tooling assembly for forming bend-controlling displacements in a sheet of material suitable for bending along a bend line. The tooling assembly may include one or more punch blades, a punch blade block having one or more recesses dimensioned and configured to receive the punch blades, a die block having one or more recesses corresponding in number to the number of punch blades, and a die block unit having a receptacle configured to receive the die block, one of the punch blade block and the die block unit being configured to reciprocate with respect to the other. The punch blades and the die block may include hardened steel and the punch blade block and the die block may include non-hardened steel. At least one of the punch blade block and the die block may be removable. The punch blades and the die block recesses may be configured to form displacements with a portion of the periphery of the displacement extending along and adjacent to the bend line.

The punch blade block may be configured to position the portion of the periphery adjacent the bend line with an edge and the sheet of material with a corresponding opposed face configured and positioned to produce edge-to-face engagement of the sheet of material during bending. A plurality of punch blades may be arranged along a plurality of bend lines and configured to form a plurality of bend lines simultaneously. At least one of the punch blades may be electrical-discharged-machined hardened steel. At least one of the punch blades may be ground, sectioned and cut to length.

At least one of the punch blades may include a plurality of shear surfaces and may be removably received in its respective recess of the punch blade block, wherein the punch blade may be reoriented in its respective recess to utilize a second one of said shear surfaces after a first one of said shear surfaces wears. The punch blade may be reoriented in its respective recess to utilize a second, third and/or fourth one of said shear surfaces after a first one of said shear surfaces wears. At least one of the punch blades may include a detent for releasable securement within a respective recess of the punch blade block.

The tooling assembly may include a threaded fastener and an expandable washer dimensioned and configured to engage the detent for securing a respective punch blade within a respective recess of the punch blade block. The detent may include a shoulder against which the expandable washer abuts against for removal of the punch blade from the respective recess. The tooling assembly may include an extractor for removing the expandable washer and, in turn, the punch blade from the punch blade block. The expandable washer may include internal threads for threaded engagement with the extractor.

The die block unit may include a receptacle configured to removably receive the die block. The receptacle may have a channel. The receptacle may have a shape that substantially corresponds to the shape of the die block. The receptacle may be configured to receive two die blocks. The two die blocks may be oriented at an angle to one another. The die block may include a shear bar and a discrete joggle bar. The shear bar and the joggle bar may include mating surfaces. The mating surfaces may be inclined. The die block may include one or more shims. The die block may include electrical-discharged-machined hardened steel. The die block may include a plurality of first shear surfaces and a plurality of second shear surfaces, wherein the die block may be removed from the die block unit after the first shear surfaces wear, turned upside down, and inserted into the die block to utilize the second shear surfaces.

Another aspect of the present invention is directed to a punch press machine that includes any of the above-described tooling assemblies and/or utilizes any of the above-described methods. Yet another aspect of the present invention is directed to methods of forming for forming bend controlling displacements in a sheet material, the method including the steps: providing any of the above-described the tooling assemblies; inserting a sheet material between the punch blades and the die block; and forming displacements on the sheet material, as well as sheet materials formed by the above-described methods, and/or three-dimensional articles formed from the above-described sheet materials. Three-dimensional articles may include electronic components, automotive components, appliance parts, truck components, RF shields, HVAC components, and/or aerospace components.

The method and apparatus of the present invention have other 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 certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary apparatus for forming a sheet material with bend controlling displacements.

FIG. 2 is a plane view of an exemplary sheet material formed with bend controlling displacements by the apparatus of FIG. 1.

FIG. 3 is an enlarged view of an exemplary upper punch and die set of the apparatus of FIG. 1.

FIG. 4 is a cross-sectional view of an exemplary punch and die set that may be used with the apparatus of FIG. 1.

FIG. 5 is an isometric view of the punch set of FIG. 4.

FIG. 6 is an exploded isometric view of the punch set of FIG. 4.

FIG. 7 is an enlarged isometric view of an exemplary replaceable punch lance of the punch set of FIG. 4.

FIG. 8A through 8F are a series of cross-sectional views illustrating the exemplary installation and removal of the punch lance of FIG. 7 in the punch set of FIG. 4.

FIG. 9 is a partial elevational and partial cross-sectional view showing an exemplary extraction tool for removing the punch lance of FIG. 7 from the punch set of FIG. 4.

FIG. 10 is an isometric view of the die set of FIG. 4.

FIG. 11 is an exploded isometric view of the die set of FIG. 4.

FIG. 12 is another exploded isometric view of the die set of FIG. 4.

FIG. 13 is a further exploded isometric view of the die set of FIG. 4.

FIGS. 14A and 14B are respective plan and end views of the die set of FIG. 4.

FIGS. 15A and 15B are respective plan and end views of another exemplary die set similar to that shown in FIG. 4.

FIG. 16 is an isometric view of another exemplary die set in accordance with the present invention similar to the die set of FIG. 4.

FIG. 17 is an exploded isometric view of the die set of

FIG. 16.

FIG. 18 is an isometric view of another exemplary die set.

FIG. 19 is an isometric view of another exemplary die set.

FIG. 20 is an isometric view of another exemplary sheet of material showing the progression of the sheet material from a blank sheet, to a stamped and shaped sheet, and to a final sheet.

FIG. 21A is an isometric view of an exemplary die set for forming the sheet of material of FIG. 20, the figure schematically illustrating the sheet of material between the die set. FIG. 21B and FIG. 21C are enlarged views of the die set's upper and lower assemblies, respectively.

FIG. 22 is an isometric view of another exemplary die set assembly similar to that of FIG. 21C having modular die block subassemblies corresponding to bend lines and intersections thereof.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to various exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings and described below. While the invention will be described in conjunction with several exemplary embodiments, it will be understood that present description is not intended to limit the invention to those exemplary embodiments. On the contrary, the invention is 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, attention is directed to FIGS. 1A and 1B, which illustrate an exemplary machine press, generally, designated by the numeral 30, that may be used to form bend-controlling displacements 32 in a substantially two-dimensional (2D) sheet material work piece 33 to facilitate bending into three-dimensional (3D) shapes. As used herein, the terms “punch press” and “machine press” are largely synonymous in that they are used to refer to a machine or system which includes tooling that having one or more male punches with one or more corresponding female dies configured to punch, stamp or press shapes into the sheet material work piece. The exemplary system is particularly well suited to be used to form sheet materials having engineered fold lines which facilitate low-force and/or precision bending along predetermined fold lines.

In this regard, the apparatus of the present invention is particularly forming for bend-controlling displacements in 2D sheet materials to form engineered fold lines of various fold geometries and configurations including, but not limited 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 (now U.S. Patent Application Publication No. 2005/0005670 A1), and U.S. Pat. No. 7,032,426, U.S. patent application Ser. No. 10/931,615 (now U.S. Patent Application Publication No. 2005/0097937 A1), U.S. patent application Ser. No. 10/985,373 (now U.S. Patent Application Publication No. 2005/0061049 A1), U.S. patent application Ser. No. 11/357,934 (now U.S. Patent Application Publication No. 2006/0261139 A1), U.S. patent application Ser. No. 10/952,357 (now U.S. Patent Application Publication No. 2005/0064138 A1), U.S. patent application Ser. No. 11/384,216 (now U.S. Patent Application Publication No. 2006/0207212 A1), U.S. patent application Ser. No. 11/080,288 (now U.S. Pat. No. 7,350,390 B2), U.S. patent application Ser. No. 11/374,828 (now U.S. Patent Application Publication No. 2006/0213245 A1), U.S. patent application Ser. No. 11/180,398 (now U.S. Patent Application Publication No. 2006/0021413 A1, U.S. patent application Ser. No. 11/290,968 (now U.S. Patent Application publication No. 2006/0075798 A1, and U.S. patent application Ser. No. 11/411,440, the entire contents of which patents and patent applications are incorporated herein for all purposes by this reference.

As described in the above-mentioned applications, some applications for the precision bending of sheet materials is in connection with the production of 3D articles including, but not limited to, electronic component chassis, automotive components, transport components, construction components, appliances parts, truck components, RF shields, HVAC components, aerospace components, and the like. Such chassis often are highly complex so as to enable the positioning of a multiplicity of components in three-dimensional arrays inside the eventual housing for the electronic equipment. Since laser cutting and water jet cutting are both may be somewhat more expensive, it may be particularly desirable to be able to form chassis for electronic equipment, and numerous other lower cost housings and the like, using-relatively lower cost, high-production displacement forming techniques such as punching, stamping, roll forming and the like. Depending on the particular context of the manufacturing application, the displacement forming techniques may be used as either an alternative to, or as an adjunct to, the cutting and/or other forming techniques. The present application, therefore, illustrates how these displacement forming processes can be applied to sheet materials.

With continued reference to FIG. 1, the punch press system 30 includes tooling in the form of an upper punch assembly 35 and a corresponding lower die assembly 37 which are preferably keyed to one another in slides such that they reciprocate toward and away from one another in an otherwise conventional manner. The illustrated embodiment is “form down” in that the displacements are formed downwardly. One will appreciated that the assembly could be reversed with the die assembly mounted above the punch assembly (i.e., “form up”), or with a combination form-up and form-down configurations. Similarly, the punch and die assemblies may be movably mounted relative to one another in some other suitable fashion. For example, the punch and die assemblies may be arranged to move horizontally with respect to one another. The illustrated vertically oriented configuration has certain advantages. For example, the vertically oriented configuration allows your work piece to merely be placed upon the lower assembly and held in place by the force of gravity. This is particularly useful for clobbering. For example, when the punching process also shears the peripheral shape of the sheet material, it is generally not necessary to specifically locate the work piece with respect to the upper and lower assemblies. In this case, a coil stand and feeder may be provided to feed coil stock to the punch press system, either in addition to or instead of hand placement and mechanical placement as well.

As shown in work piece of FIG. 2, the punch press system may be used to form a number of displacements in the work piece. In this particular example, the punch press system has formed the work piece into an intermediate article that includes a plurality of bend-controlling displacements 32 as well as a number of other displacement features such as a protruding component mount 39, latching tabs 40 and a latching anchor 42. One will appreciate that the punch press system may also be configured to provide fewer or additional displacement features and/or cut or form the work piece to a particular length and/or shape.

With continued reference to FIG. 2, exemplary bend-controlling displacements may be formed along predetermined or desired bending lines 44 in a manner similar to the slits, tongues, and displacements discussed in the above-mentioned patents and patent applications. In the illustrated embodiment, the displacements include a flat zone 46 and an inclined transition zone 47 of the type described in the above-mentioned '828 application. The flat zone is substantially parallel to the overall plane of the sheet material, while the transition zone extends at an angle and interconnects the flat zone with the remainder of the sheet, in a manner that may be seen in FIG. 18A of the '828 application.

The bend-controlling displacements are generally formed by displacement in the direction of the thickness of the sheet material so that a portion of the periphery of the displacement closest to bend line provides an edge and a corresponding opposed face configured and positioned to produce edge-to-face engagement during subsequent bending of the 2D sheet material to form a 3D product usually as a result of shearing the material parallel and proximate to the fold line as is described in the above-mentioned '828 application. The illustrated bend-controlling displacement includes a flat zone having an elongated portion with substantially semicircular ends. One will appreciate, however, that the actual geometry of the flat zone may vary. For example, curves having multiple radii may be used to form the elongated portion and ends, and oval, elliptical, parabolic and/or other suitable curved shapes may also be used.

In general, the configuration of bend-controlling displacements required for a particular sheet of material may vary depending upon the geometry and configuration of the sheet of material. In some situations, there may be certain advantages in “standardizing” the size of elongated displacements in order to reduce tooling costs and otherwise simplify the design process and tool service. For example, the elongated-displacements may be standardized in one, two, three or more “standard” sizes for sheet materials of a particular thickness, particular type of material and/or other parameters.

Turning now to FIG. 3, upper punch assembly 35 includes a plurality of hardened punch blades 49 positioned to form the bend-controlling displacements in the sheet material. The upper punch assembly may also include other punches to form other features in the sheet material, such as mount punch 51 and latch punch 53. The illustrated punch assembly can thusly be used to simultaneously form bend-controlling displacements along a plurality of bend lines and other features including the mount and/or the latches. Of course, the punch assembly could also be configured to form the various features separately, or to add or omit certain of the features. One will appreciate that the corresponding lower die assembly 37 includes a number of complimentary-shaped features to assist in forming the various displacement features of the sheet material.

In order to facilitate service, maintenance, and adjustability, the upper punch assembly includes a punch unit 54 and the lower die assembly includes a die unit 56 which are removably mounted to an otherwise conventional punch press machine 58. The respective units may be fastened to the mounts and/or upper and lower portions of the punch press machine by any suitable means including, but not limited to, threaded fasteners (e.g., block fastener 60), dowels and/or other suitable means. Preferably, but not necessarily, neither the punch unit and/or the die unit is formed of hardened metal, and may thus be milled and otherwise fabricated much less expensively than if using hardened metals.

Turning now to FIG. 4, the configuration of a punch blade or lance insert 49 and its corresponding lance cavity located in die block 61 is shown. The lance insert and the die block are preferably, but not necessarily, modular components which may be readily and quickly replaced, and which may be rotated face to face, or end to end to present fresh cutting edges to the shear position. In some aspects and in some instances, the lance insert and die block may be considered disposable. As will be discussed in greater detail below, the modular configuration of the lance insert and the die block allow for economical and efficient hard-tooling designs. In particular, the modular configuration allows for less componentry to be formed of hardened metals and lessen the amount of machining necessary to develop a hard tooling design for forming a work piece into a particular sheet material product. Preferably, but not necessarily, the lance inserts and/or the lance cavities are formed of pre-hardened stock which may be ground, hard milled and/or electrical discharge machined (EDM) into their final shapes. One will appreciate that other suitable means may be utilized to form pre-hardened stock into its final desired shape.

Turning now to FIG. 5 and FIG. 6, an exemplary lance insert subassembly 63 includes a plurality of lance inserts 49 mounted in an exemplary punch blade block 65, which in turn is mounted on the upper punch unit 35. The lance inserts are preferably, but not necessarily, removable from the punch blade block, which is preferably, but not necessarily, removable from the upper punch unit. The configuration and dimensions of the lance inserts generally conform to the desired shape of flat zone 46 of the bend-controlling displacements 32. As the lance inserts are subject to greater wear and tear as compared to other components of the system, their removable configuration facilitates their repositioning or replacement while the punch unit is on the punch press machine and thus decreases down time of the machine, and thus also supports regular scheduled maintenance.

The punch blade subassembly preferably, but not necessarily, has a substantially modular design with each subassembly corresponding in size and shape to one or more elongated displacements arranged along a bend line. In the illustrated embodiment, the subassembly is configured to form for bend-controlling displacements, however, one will appreciate that one, two, three or more lance inserts may be used to form a corresponding number of elongated displacements along a bend line. One will appreciate that the number and dimension of lance inserts may vary depending upon the particular design criteria of the product being formed.

In the illustrated embodiment, each lance insert is received in an exemplary corresponding punch-blade recess 67 of the punch blade block and preferably, but not necessarily, secured therein by a suitable fastener. As shown in FIG. 7, the lance inserts may be provided with detents 68 which engage with a corresponding expandable washer 70 to securely hold the lance insert in place. In the illustrated embodiment, the expandable washer is threaded, however, one will appreciate that other suitable means may be utilized.

Sandwiched between punch blade block 65 and the punch unit 54 is an exemplary hardened punch blade base 72 against which the inner ends of the lance inserts 49 abut against. As can be seen in the figures, the punch blade base may be formed of a hardened flat metal plate which can be readily and relatively inexpensively punched or otherwise fabricated. Significantly, such configuration allows the punch blade block 65 to be formed of non-hardened metal which further contributes to a significant cost savings as the non-hardened punch blade block may be fabricated much less expensively, and in less time, than would a conventional hardened punch blade block.

Turning now to FIG. 8A to FIG. 8C, the inner ends of the lance inserts abut against the punch blade base as the fastener is secured and the thusly precisely positioned such that the lance insert protrude from the punch blade block 65 to form a bend-controlling displacement having the desired displacement depth. Preferably the detent 68 has a concave profile 74 which allows the expandable washer to push lance inserts 49 against punch blade base 72 and securely fasten the lance insert within recess 67 of punch blade block 65, as shown in FIG. 8C. Also, lance inserts 49 are dimensioned such that the blades extend a minimal amount outwardly from punch blade block 65. Such configuration provides the lance inserts with more lateral stability and thus minimizes the bending moment of the lance inserts and thereby serves to promote longer wear and tear and reduce the likelihood of fracture. One will appreciate that in the event a stripper plate is utilized, the lance inserts may extend outwardly from the punch blade block a corresponding amount to accommodate for the thickness of the stripper plate such that the lance inserts extend through the stripper plate and outwardly therefrom.

Preferably, the lance inserts and expandable washers are configured to facilitate removal of the lance insert from the punch blade block. In the illustrated embodiment, expandable washer 70 has internal threads 75 and detent 68 has a shoulder 77 to facilitate removal of lance inserts 49 from the punch blade block 65 as can be seen in FIG. 8D through FIG. 8F. In particular, an extractor in the form of a removal bolt 79 may be used to threadably engage expandable washer 70 to pull the lance insert from the punch blade block. As shown in FIG. 8E, the expandable washer will engage shoulder 77 and allow the extractor for apply downward force against lance insert 49 and thus remove the lance insert. The extractor may further include a lever 81 or other suitable means to apply downward force, as is illustrated by arrow F in FIG. 9.

In the illustrated embodiment, lance inserts have flat ends, that is, the bottom surfaces of the ends are substantially parallel to the remainder of the sheet material and/or parallel to the press bed. Such a flat configuration is advantageous in that it will lessen wear on the lance inserts and lengthen the life span of the lance inserts. For example, lance inserts having flat bottoms would reduce the rapid wear that may occur with sloped bottom punches. Furthermore, sloped bottom tools generally wear more rapidly, are more expensive to make and difficult to reshape. Preferably, the lance inserts are both horizontally and vertically symmetrical such that as one edge of the punch block wears, the punch block may be rotated 180° about its vertical axis to utilize both of its lower edges, and then flipped upside down to utilize both of its upper edges (i.e., edges 82, 82′, 82″ and 82′″ as shown in FIG. 7). As such, the life of the lance inserts may be doubled or quadrupled as each lance is provided with four shear edges, only one of which is utilized at a time.

Turning now to FIG. 10 through FIG. 13, a die block subassembly 84 includes die block 61 removably seated in the die unit 56. In this regard, the die unit includes a channel 86 for removably receiving the die block. As noted above, the die unit may be formed of non-hardened metals, and thus the channel may be formed and the die block otherwise fabricated or milled relatively inexpensively.

On the other hand, the die block 61 is formed of hardened steel and/or other hardened metals. Since the die block is relatively small, the die block may be readily machined relatively quickly using standard machining techniques for hardened metals. For example, the die block may be machined using electrical discharge machining (EDM) or other suitable means. In any event, only the relatively small die block(s) are hardened, and the die unit which receives the die block(s) may be unhardened. Accordingly, EDM and other relatively expensive hard milling/manufacturing process are only required to make smaller parts and simpler shapes, and thus may contribute to a significant savings of time and money.

With reference to FIG. 12, the configuration and dimensions of die block 61 generally conform to the desired elevational profile of the bend-controlling displacements. In the illustrated embodiment, the die block includes four die block recesses 88 which are arranged and dimensioned to cooperate with the four lance inserts 49 to form four respective displacements 32 in sheet material 33. As noted above, the lance inserts substantially correspond in shape to the desired flat zone 46 of the displacement 32, namely the depressed inner surface of the desired flat zone. The die block recesses 88, on the other hand, substantially conforms in shape with the desired shape of the flat zone 46 and the transition zone 47, namely the protruding outer surface thereof. It should be noted that in this case, “inner surface” and “outer surface” merely refer to the geometry of the displacements, namely “inner surface” is used to denote the depressed region made in the sheet material by the lance inserts, while “outer surface” is used to denote the projecting region of the displacement projecting from the remainder of the sheet material.

The die block 44 includes a shear edge 89 which is dimensioned and positioned such that it cooperates with an adjacent edge of a respective lance insert 49 in order to cause the displacement to shear substantially parallel to and/or along the respective bend line. In particular, the tight tolerance between the shear edge of die block 44 and a corresponding lance insert 49 will cause flat zone 46 of displacement 32 to shear parallel to and/or along bend line 44, while the increased tolerance between the opposing edge 91 of the die block recess and the opposing edge 82′ of the lance insert 49 allows for non-shearing displacement of transition zone 47 (see, e.g., FIG. 4).

With continued reference to FIG. 12 and FIG. 13, the die block 44 may have a split body having a shear bar 93 and a joggle bar 95, both of which are formed of hardened steel and/or other suitable materials. The shear edges 89 and recesses 88 of the die block are machined into the shear bar. Conventional means may be utilized for machining the shear bar, however, the relatively small size and the open configuration of shear bar 93 is particularly well suited for EDM and, in particular, wire-cut EDM or wire electrical discharge machining (WEDM) to form the recesses. One will appreciate, however, that hard milling and other suitable means may be utilized to machine the shear bar. The relatively small size and simple geometric shape of the joggle bar 95 is also conducive to machining by conventional means but, as one will appreciate, the small size and basic geometry of the joggle bar allows for relatively less expensive manufacture. Both the shear and joggle bars may be WEDM or hard milled end cut from hardened and ground bar stock, and in the case of the shear bar, the inclined surfaces may also be notched using WEDM or hard milling processes. One will appreciate that other suitable means may be used to shape the shear and joggle bars.

The die block subassembly 84 may include one or more shims 96 thus allowing for the use of die blocks of various sizes. In particular, side shims allow for die blocks of various widths within channel 86, while bottom shims allow for die blocks of various depths within channel 86. One will further appreciate that channel 86 allows for die blocks of various lengths.

In the illustrated embodiment, the die block 44 preferably, but not necessarily, has a split body. In this regard, shear bar 93 and joggle bar 95 may have cooperating split surfaces 98, 100, which are inclined or angled and together serve to wedge together and secure the die block within channel 86. Such an inclined surface, however, is not essential. For example, in the embodiment of FIG. 15A and FIG. 15B, the split surfaces 98, 100 are substantially vertical, that is, substantially perpendicular to the bottom of channel 86. Such vertical configuration leads to easier and less expensive fabrication. In this case, additional threaded fasteners or other suitable fastening means may be used to secure the shear bar 93a to the die unit 56.

In other embodiments, the die unit channel may be replaced with a receptacle 102 which substantially conforms in shape with, and receives the die block 44a, as shown in

FIG. 16 and FIG. 17. In this embodiment, the die unit 56a is machined to receive a specifically dimensioned and shaped die block 44a. As noted above, the die unit is not formed of hardened metal and thus the receptacle may be relatively easily machined to the die unit 56a. FIG. 18 shows yet another embodiment where a receptacle 102b is formed to receive two closely fitting die blocks 61b, which configuration may be used to form displacements along two bend lines intersecting at a corner 103. In this case, the shear bar 93b and the joggle bar 95b may be machined to include cooperating mating surfaces 105, 107, which together facilitate proper positioning of the die block 44b within the receptacle 102b.

FIG. 19 illustrates still a further embodiment in which die block 61c is linearly segmented. In this embodiment, the die block is not longitudinally split and instead has monolithically formed segments 109 having portions on either side of a lance cavity. As shown, the segments may end between lance cavities 88′, 88′, or may terminate through a lance cavity 88″. As noted above, threaded fasteners or other suitable fastening means may be used to secure the die block components to the die unit. In the illustrated embodiment, threaded fasteners 110 cooperate with fastener recesses to removably secure the die block segments. As shown, the fastener recess may be positioned intermediate ends (e.g., recess 112), at the ends (e.g., recess 112′), or may extend along the segment (e.g., recess 112″). In the illustrated embodiment, fastener recess 112″ extends the length of a segment, however, one will appreciate that such a recess may extend along a partial length or an entire length of a segment. As illustrated, washers may be, but need not be, used to secure the die block components to the die unit.

In operation and use, the geometry and configuration of the bend-controlling displacements allows for the work piece to be readily removed from the lower die assembly. One will, however, appreciate that a die ejector may be used as desired, or that other well known means such as stripping may also be used in which the sheet material is extracted from the lower die portion of the punch assembly. In both cases, such ejection can be form up, form down, or a combination thereof.

Turning now to FIG. 21A, machine press system 30d is similar to press system 30 described above but is configured for increased efficiency in terms of simplified machine tool design and in terms of reducing the number of manufacturing processes generally required to fabricate a sheet material product such as sheet material 33d. A blank sheet material 33d′ may undergo a single “hit” within the machine press system to form and shape the blank into sheet product 33d″, as shown in FIG. 20.

In many aspects punch assembly 35d and die assembly 37d are similar to the above-described upper punch assembly 35 and lower die assembly 37, as well as the above-mentioned lance punch subassembly 63, and die block subassembly 84. In the exemplary embodiment of FIG. 21A, the upper punch assembly 35d and lower die assembly 37d are keyed to one another by slide posts 114 and slide collars 116 such that the punch and die assemblies may reciprocate relative to one another. Although FIG. 21A schematically illustrates the punch and die assemblies in butterflying relation to one another, one will appreciate that the slide collars slidingly receive slide posts such that the upper punch assembly 35d reciprocates up and down relative to die assembly 37d. One will further appreciate that machine press system 30d may be configured such that die assembly moves up and down relative to the punch assembly, that the punch assembly may be situated below the die assembly, that the two assemblies may be arranged to reciprocate horizontally relative to one another, or that the two assemblies may be arranged to reciprocate at an angle relative to one another.

Punch assembly 35d includes a punch block 65d. As discussed below, the punch block is similar to the above-mentioned punch block 65 but includes a number of punch blade recesses arranged along a number of bend lines, which recesses receive a corresponding number of punch blades 49d. In the exemplary embodiment, the punch block is sectioned and formed of multiple members or punch modules 117. Similarly, die assembly 37d includes a die block 61d, which is similar to die block segment 109 discussed above but includes a number of lance cavities 88d arranged along a number of bend lines. In the exemplary embodiment, the die block is also sectioned and formed of multiple members or die block modules 119. One will appreciate, however, that the punch block and/or the die block may be formed of one, two, or more modules. Advantageously, the punch block and/or the die block are formed of metal plate material having substantially constant thickness. As such, complex machining operations such as milling and grinding are reduced and/or eliminated thereby significantly reducing the cost of the punch and die blocks.

In the exemplary embodiment shown in FIGS. 21A through 21D, the punch assembly 54d is also configured to mate with die assembly 56d to effect shearing of a peripheral shape into a sheet material blank 33d′ and form sheet product 33d″. In particular, the punch assembly is provided with corner shear blocks 121 having shear edges complementary in shape to the peripheral shape of die block 61d in order to shear corner portions 123 from sheet material 33d, as shown in FIGS. 20 and 21A. One will appreciate that various embodiments may be configured to remove various shapes, corners and otherwise, from the sheet material as desired.

One will appreciate that the corner shear blocks 121 and the die block 61d each have cooperating shear edges and thus are preferably formed of hardened steel and/or other suitable materials. In various embodiments, die block 61d and corner shear blocks 121 are manufactured from the same plate of material. As shown in FIG. 21A, the die block and corner shear blocks are complementarily shaped with respect to each other. The corner shear blocks may be fabricated by removing the shear block material from the die block material by EDM, WEDM, and/or other suitable means. Such a configuration reduces material waste and manufacturing processing. Accordingly, such configuration allows both the die block and corner shear blocks to be cut utilizing EDM or other suitable processes from a single hardened plate, thus greatly simplifying fabrication and greatly reducing the amount of waste material.

Once the lance cavities 88d are formed in die block 61d, preferably with EDM, WEDM, and/or other suitable processes, the die block may be mounted on the platen of lower die assembly 37d. Similarly, corner shear blocks 121 may be mounted on the platen of upper punch assembly 35d. Shims 124 may be utilized to appropriately space the shear corner blocks from the platen of the upper die assembly in order to effect sufficient overlapping of the corner shear blocks 121 and die block 61d to effect shearing corner portions 123 from sheet material 33d.

Punch assembly 35d is configured to receive punch blades 49 within the punch block 65d in a similar manner as lance inserts 49 are mounted within punch blade block 65 described above. One will appreciate that other suitable means may be utilized to secure the punch blades within the punch block.

As shown, in FIG. 21C, the punch block may be composed of one, two, three or more punch modules 117 which include portions of one or more bend lines and/or entire bend lines. One will appreciate that the punch modules may be configured in various manners. The punch modules may be secured to punch assembly 35d by threaded fasteners (not shown) and/or other conventional means.

As is the case of the punch blade blocks discussed above, punch block 65d need not be formed of hardened metal. Nonetheless, in various embodiments, the punch modules may be formed of pre-hardened stock.

Turning to FIG. 21A, the operation and use of press system 30d will now be described. Punch assembly 35d is configured to cooperate with corresponding die assembly 37d. In various embodiments, the press system hits the sheet of material to produce a sheet product in a single hit (shown, e.g., in FIG. 21A). “One-step” and “single hit” refer to the action of the press system and generally refer to one or substantially one actuation cycle. Thus, the sheet product is formed by stamping or punching engagement of punch assembly 35d with die assembly 37d. Thereafter, the punch assembly is moved back to an initial position and the press opened so that the sheet product may be removed, manually and/or in an automated process. The process may be performed in substantially a single hit, for example, actuation of the punch assembly in a single direction may be divided into sub-steps. In contrast to other systems, however, the punch assembly is not actuated in multiple, large steps. Material is placed in the press, the press system is actuated to perform one process, and the sheet product is removed. Thereafter, limited manufacturing (e.g. finishing) is necessary after the punch cycle. The sheet does not have to be punched again to form additional primary features such as bend lines and the like.

Sheet product 33d″ may include a plurality of bend lines, intersecting and/or non-intersecting, as well as other features such as fastening devices and aesthetics. The punch and/or die assemblies may be configured to produce one or more features of the sheet product, and/or support tooling to produce said features.

In various embodiments, the punch block and/or the die block may be configured to produce bend-controlling displacements defining standardized bend lines and/or other standardized features. For example, intersections of multiple bend lines may be standardized, and/or portions of bend lines may be standardized. Also, the punch block and/or die block may also be configured to produce other standardized features in the sheet product. Modules may be utilized to form such standardized features, the configuration of which modules may be determined by location, feature type, or other factors depending on the application. In some embodiments, one set of modules may correspond to regions of the sheet product with intersecting bend lines, and another set of modules may correspond to bend lines and features connecting these intersection regions. The configuration and use of the modules may accordingly be mixed-and-matched as desired for a particular application. Such modularity provides several benefits such tool cost savings and greater flexibility. Although in various embodiments the punch and die assembly may be hard tooled and capable of forming features in a sheet material in a one-step process, the modules allow for the tool to be easily changed for different design processes such as different sized lance and lance cavities, etc.

With reference to FIG. 22, the press system may be provided with a platen 126 configured to receive various modules. For example, the platen may be provided with modular recesses 128 and/or modular channels 130 to receive standardized intersection modules 131 and bend line modules 133 in a manner similar to that described above and shown in FIG. 18 and other figures.

In various embodiments, an ejector 135 may be provided to facilitate removal of the material subsequent to punching of the punch assembly (see, e.g., FIG. 22). Because of the lower force of engagement of the sheet with the punch assembly and die assembly of the present invention, the ejector may not require high force application. The ejector may be a spring ejector, stripper plate, or other like assembly. In various embodiments, the ejector is formed within a recess in the die cavity.

In various embodiments, the punch and die assemblies may be configured to form other features such as spring clips 137, conical indentations 138, and/or other conventional stamped and punched features (see, e.g., FIG. 22). Also, the punch and die assemblies may be modified to reduce the tonnage required for forming such features and sheared edges. For example, the punch and die assemblies may be provided with tapered or “crowned” surfaces 140 (see, e.g., FIG. 21C).

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 exemplary embodiments 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”, “d” and “e” 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.

METHOD AND APPARATUS FOR FORMING BEND CONTROLLING DISPLACEMENTS IN SHEET MATERIAL

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