This application claims priority from U.S. patent application Ser. No. 10/569,507 filed Feb. 27, 2006 which claims priority from PCT Application No. PCT/CA2004/001569 filed Aug. 27, 2004, which claims priority from U.S. Provisional Patent Application No. 60/498,586 filed Aug. 29, 2003 entitled Process of Production of Disposable Wooden Cutlery and Product Thereof.
This invention relates to both an improved process for manufacturing disposable wooden eating cutlery and other utensils, and an improved design of the utensils made by that process utilizing wood veneer from generally non-marketable wood species.
Disposable cutlery and other utensils (herein collectively referred to as utensils) manufactured from wood veneer are well known, and are gaining in popularity as these utensils are viewed as environmentally friendly in both their manufacture and disposal. However, both the design of the utensil and the process by which they are manufactured have failed to evolve so as to overcome the strength deficiencies of the thin cross-section of veneer and to overcome the inefficiencies of the manufacturing process.
Veneer strips which have been stripped from a wood block are first soaked in hot water until the lignins are softened then cut or stamped into the desired shapes, that is forks, spoons, knives and the like. The cut-outs are then placed into a mold where under pressure they are formed into the shape of the desired utensil and with the application of heat the moisture is driven off so that a stable form ensues.
In the prior art, veneer utensil shapes have been cut at one location, transported or moved to a matrix at a second location, which is further moved into vertical alignment under a die where through the application of pressure and heat the utensil is formed. Such production is invariably inefficient and is severely limited in its production capacity.
For example, in the prior art applicant is aware of the German Patent No. DE 43 18 043 A1 which issued Dec. 1, 1994 to Langer et al. for A Method for Forming Flat Parts of Wood. In this application the cut cutlery blanks are formed at the perimeter of a revolving multi-stationed table. The blanks are radially translated from their initial cutting location on to a lower portion of a form positioned on the table. Incremental rotation of the table brings the lower form into vertical alignment with an upper form, which can then be pressed together with the lower. The mated forms are then rotated to a heating station and then to a dispensing station.
In general, applicant has found that prior art wooden veneer utensils such as forks suffer from breakage of the handle near its confluence or intersection with the head of the utensil. Consequently, in applicant's view the related prior art production processes are not only inefficient and fairly slow but have produced inferior product.
It is therefore one of the objects of this invention is to provide a utensil design, for example useful for forks and spoons, or combinations thereof, which will strengthen the neck between the handle and the load-engaging member or head so as to avoid breakage of the utensil at the neck, and to provide a method and process for making same.
The present invention is a process for manufacturing eating utensils, such as knives, forks and spoons from non-merchantable timber balks where veneer is peeled from the balk, soaked in hot water and fed onto a die table containing one or more specifically shaped apertures. Veneer strips which have been stripped from a wood block are first soaked in hot water until the lignins are softened then cut or stamped into the desired shapes, that is forks, spoons, knives and the like. The cut-outs are then placed into a mold where under pressure they are formed into the shape of the desired utensil and with the application of heat the moisture is driven off so that a stable form ensues. Veneer pieces may be placed upon the die table immediately underneath a waste stripping plate which is securely mounted to and spaced above the die and which is suitably apertured so as to allow free through passage of the projecting punches. Upon completion of a punching cycle, the punches are withdrawn from the veneer through the apertures of the waste stripping plate ensuring that complete separation occurs of the punches and the remainder of the waste veneer.
Cutlery cut-outs are formed by the pressure of a vertically actuated press, the face of which contains projecting punches conforming closely to the apertures in the die table which force the veneer pieces completely through the die table.
Female molds mounted to an endless conveyor passing under the die carry the cut-outs into close proximity with male molds positioned on an endless conveyor in vertical alignment immediately above it.
Clamps mounted on endless conveyors, laterally disposed on each side of the male and female mold conveyors are adapted to bring the male and female mold components into further close proximity so as to transfer the mold shapes to the cutlery veneer. The endless conveyors carrying both the male and female molds pass through heaters, such as a microwave source for example, which maintain the mold elements at a suitable temperature for curing the cutlery.
Mold components are readily removable from the platens for replacement of defective molds or for installing molds for forming different utensils.
The mold components for forming forks and similar utensils are designed to create a dorsal rib extending along the handle and well into the head of the utensil, such as the bowl to strengthen the handle at the confluence with the head so as to avoid breakage.
In summary, the present invention is a disposable wooden utensil and a method and process for making same. The utensil may be characterized as including a handle having a distal end and an opposite neck end. A load-engaging member extends cantilevered from the neck end in generally coplanar alignment with the handle so as to form a neck between the handle and the load-engaging member. A raised dorsal ridge is formed substantially medially along the handle and extends substantially along the load-engaging member. The handle, the load-engaging member and the dorsal ridge have a contiguous upper surface and an opposite contiguous lower surface. The upper surface and the lower surface of the handle, the load-engaging member and the dorsal ridge may be formed from common sheets of wood veneer. The dorsal ridge may be linear, and may extend from the neck and along the load-engaging member between at least one third and substantially one half of the length of the load-engaging member. The utensil may be formed of at least one sheet of wood veneer. Advantageously, the load-engaging member is formed as the head of a piece of cutlery for engaging food.
In one embodiment, the utensil is formed as a lamination of at least two sheets of wood veneer. The lamination is between the upper surface of the utensil and the lower surface of the utensil, and in the handle, formed in a plane substantially containing the handle. The lamination may be of wood veneer sheets from different species of wood, for example wood chosen from the group consisting of non-merchantable species such as Aspen and Birch. The lamination may be laminated with a corn starch binder.
In a further embodiment wherein each sheet of wood veneer has a corresponding grain angle, the grain angle of adjacent sheets of wood veneer is mismatched between the adjacent sheets.
In one exemplary process according to the present invention for producing a disposable wooden utensil, the process includes forming from at least one sheet of wood veneer a handle having a distal end and an opposite neck end; forming from the at least one sheet of wood veneer a load-engaging member extending cantilevered from the neck end in generally coplanar alignment with the handle so as to form a neck between the handle and the load-engaging member; and, forming from the at least one sheet of wood veneer a raised dorsal ridge substantially medially along the handle and extending substantially along the load-engaging member. In the process each sheet of the at least one sheet of wood veneer is shaped or formed into an outline of the utensil by pressing at least one punch against a sheet of wood veneer which is sandwiched between the at least one punch and correspondingly shaped apertures in a die table, and is molded to form the utensil in mating male and female molds. The at least one sheet of wood veneer may advantageously be heated in a solvent prior to being shaped into an outline of the utensil so as to soften lignins in the wood veneer. The molds may be heated so as to cure the utensil in the molds.
a is an enlarged isometric view of a portion of
a is a sectional view taken on line 7a-7a of
b is a sectional view taken on line 7b-7b of
c is a sectional view taken on line 7c-7c of
a is a plan view of the utensil illustrated in
a is a plan view of the utensil illustrated in
a is a sectional view along line 19a-19a in
With respect to fibre selection, the selection of appropriate source logs for production of wooden cutlery is important. Balk material which is stressed from knots or sweeps results in twisted end product and is therefore unacceptable. The challenge throughout is to avoid the end-product being twisted, spiraled or corkscrewed. Infeed material should be in the range of 10″ to 20″ diameter. Typically, logs are delivered in approximately 9 foot lengths, which is appropriate for 5 balks each. Balks are cut to 18½″ lengths, debarked, made round and have their centre points identified for veneering lathe mounting.
Debarked balks are veneered at approximately 0.038″ thickness, with outside width set at 17¾″ and a centre-line score set at 8⅞″ for ease of folding. Folding along the score creates two thicknesses of veneer each 8⅞″ wide. The veneering process should be conducted using the “pith centre” of the balk as the radius turning centre, otherwise, stresses in the layered veneer cause twisting in the finished product. Thus, there can be no optimized veneer harvesting from balks. Veneer coming off the lathe is rolled onto a drum equipped with an automatic tensioner and stored as one drum per balk.
As used herein, and as would be known to one skilled in the art, the term “winter wood” refers to the dark-ring wood peeled off a balk during veneering on the lathe, and the term “summer wood” refers to the white-ring wood peeled off the balk during veneering on the lathe. Thus as a balk is veneered, the resulting veneer sheet has portions of winter wood inter-leaved between portions of summer wood. Applicants have determined that there exists different characteristics between winter and summer wood in Aspen and Birch wood which lend to improvements in production of and quality of the wooden cutlery which are the subject of the present invention.
Veneer is taken off the storage drum, examined for imperfections, and cut as required (generally into approximately 5 foot lengths). It is then fed through a series of heated-drum rolls at variable speeds and temperatures to reduce moisture content to 14-17 percent. It then has a paper ribbon glued to one edge for additional cross-grain strength required in further processing. This preconditioned veneer is set aside for a period of time to allow it to “normalize” its moisture content.
A final stage conditioning is applied after “normalizing” to further reduce moisture content on the glue side while maintaining enough moisture content on the non-glue side to prevent cracking. In particular a drum dryer at 240 degrees Celsius is used, and the pre-conditioned veneer is run over the drum, held against the drum by a one quarter inch open weave belt which allows steam to escape. It has been found that the heat of the drum causes migration of moisture away from the drum surface thereby reducing the moisture content on the drum side of the veneer and leaving an increased moisture content on the belt side of the veneer, that is the side of the veneer opposite to the drum side. The drum side of the veneer becomes the side to which glue is applied, that is, becomes the glue side.
Pre-heated veneer is fed to the glue station directly from the final stage conditioning, where it is automatically clipped to appropriate utensil length. Thermal setting food grade catalytic glue is spray applied and flashed with infrared heat. The veneer is then folded and heat sealed into a double thickness oblong “pocket” in preparation for punching into 8 product blanks, all attached to a connecting sprue (six blanks for soup spoons).
The “pocket” from the glue station is delivered to the punch station automatically. The pocket is next inserted under the steel-rule die punch via an air operated open centre “picture frame” device. On the down stroke of the punch, the product blanks are cut from the pocket. On the up stroke the waste from the pocket is left on the deck and is extracted as the picture frame returns to its “load” position. The product is retained inside the steel rule until the waste is removed. At this point the product is extracted from the die and drops to the deck. The next pocket is inserted into the picture frame and as the frame moves forward to a position under the die, the eight piece product blank with connecting sprue on the deck is moved forward and inserted into a set of heated shaping platens.
In one embodiment heated forming platens are attached to the circumference of a rotary carousel and are indexed to be positioned at the punch station each time a set of cutlery blanks are available for insertion. These platens are heated to 260 degree C. They are male and female forming platens. They close automatically, and remain closed for 5 seconds, then release momentarily for a first “gas-off” to relieve steam and then close again and remain closed for a further 25 seconds. They close with a pressure of approximately ten metric tonnes per individual utensil. The momentary pressure release is for steam release to control delamination. Variations in this procedure may occur due to moisture content requiring for example a second gas-off 10 to 20 seconds into the second compression interval. Typically veneer made from Aspen balks will require a second gas-off and veneer made from Birch balks will require only the single gas-off. But this, again, is moisture dependent. For example, sap wood has more moisture content than hardwood, etc.
The forming plattens open automatically and the product may be removed with vacuum fingers at a station which is for example 270 degrees advanced around the rotary carousel from the punch station. The “hardened”, shaped utensils attached to their sprue are delivered to a moving chain where they are spray coated with confectioners glaze as a finish. The product travels though a heated tunnel to flash off the spray solvent.
The product may be next photographed for quality identification and then laser engraved as appropriate. Each individual utensil on the sprue is held by vacuum fingers and moved through a despruer where it is removed from its sprue and can be moved to its appropriate location according to its quality identification.
As noted above, the veneering process that is employed is atypical compared to the standard employed in most of the wood industry in that veneering must be based on the “growth centre” of the balks, rather than on the outside diameter of the balk (optimized recovery) as is normal in standard veneer production. Further, to make the product requires that there be significantly tighter controls on moisture content than is the case with simple veneering. A few points of additional moisture content will cause the glue to not set and delamination will take place. If there is too little moisture, the resulting cracking of for example the three dimensionally curved surfaces formed in the plattens makes the product useless. The process is multi-layer veneering, and successful veneering for the forming of product requires both cross-grain and longitudinal bending which means control of moisture content. As described above, the moisture content must be less on the glue side than on the finished surface side, and is produced in a single-sided hot drum conditioner.
Applicants have also determined that advantageously in production of wooden cutlery the several veneer layers are placed in approximate wood-grain alignment such that all layers of veneer run in the same direction. It has been found that this inhibits spiraling or corkscrewing of final product. Typically in the prior art, veneers have alternate layers placed the grain directions at approximately 90 degrees from each other such as in plywood or the like for cross-grain integrity increasing the strength. Despite the substantial alignment of grain direction in the multiple layers along the long axis of the wooden cutlery products the integrity of the final product is achieved through a mix of summer and winter wood. The summer wood, being the softer (lighter colored) annual ring fibre generated naturally within the tree during summer growth, the winter wood, being the harder (darker colored) annual ring fibre generated during winter growth, are allowed to overlap one another in the two or more layers of veneer used to form the cutlery, and in one embodiment of the process are allowed to randomly overlap. Since most loss of cross-grain integrity occurs in summer wood, it has been found that the mixing of overlapped summer and winter wood significantly reduces the loss of integrity due to co-linearity of grain direction in the layers of veneer in the lamination in wooden cutlery products according to the present invention.
Shape relationships between male and female forming platens for the various utensils are as follows:
The soup spoon requires a “compression profile” between the male and female platens wherein the male shape is required to contact the centre of the bowl to lock the veneer into place so that as the pressure increases and the veneers begin to compress, there is sufficient clearance for the cross fibers to creep rather than tearing and causing cracks. This is far different from the shape that is required for simple veneering.
The knife profile is such that the male and female shaping platens nearly meet under full pressure. This is because the knife edge requires that it be pressed to an extreme degree to make the cutting edge very thin and very hard. The design has the knife cutting teeth oriented such that the wood grain abuts the blade lengthwise rather than cross-grain, creating a cutting edge highly resistant to both wear and breakage.
The fork needs to have strong tines. This characteristic has been created through differentiated pressure during the shaping process.
The tea spoon as well as the other formed products has small radii built into the shaping platens so as to create a pleasant “mouth feel” free of roughness. The product must have smooth and hard surfaces to prevent moisture penetration as well as to create an acceptable mouth-feel and tactile sensation.
As stated above, the process is not the basic process typical in virtually all other veneering. In particular, temperature control is required and should be computer controlled for accuracy, moisture control is required for cracking prevention, and moisture control is required to the gluing process to avoid both delamination and dilution.
Now, with reference to the drawing figures, wherein similar characters of reference denote corresponding parts in each view, the manufacturing apparatus 10, as schematically represented in
As non-merchantable timber such as Birch and Aspen is utilized in this manufacturing process, it will be appreciated that such timber may be generally small in diameter and be of relatively short straight lengths. To create a relatively thin veneer from such wood with maximum utilization, the timber is first cut into balks, that is, pieces or members, of relatively short length (16 inches) prior to peeling the veneer.
Infeed area 12 includes a hot water bath 30 where wood veneer pieces 34 are soaked to soften the lignins. Softened veneer pieces 34 are fed to production area 14, for example on an endless conveyor belt 12a.
Veneer pieces 34 are received on a die 36 having one or more apertures 38 therein which conform to the shape of the wood utensil being manufactured. Where the saturated and softened waste veneer does not cleanly separate from punch 42a at the end of a punching cycle, an apertured stripping plate 40 is securely mounted to and spaced immediately above die 36. Apertures 40a of stripping plate 40 allow free through passage of the projecting punches on the downward utensil-forming stroke B as indicated on
Male molds 58 formed on or are removably mounted on platens 50a. Platens 50a are downstream of press 42 and die 36. Platens 50a are positioned to vertically align male molds 58 above female molds 48. Platens 50a are carried on an endless conveyor 60. Male molds 58 are thereby brought continuously into alignment over utensil cut-outs 44 carried in female molds 48.
Upper and lower press rolls 54 and 54a respectively engage upper and lower platens 50 and 50a bringing them tightly together. Endless conveyors 64a and 64b are laterally disposed on either side of upper and lower male and female mold carrying conveyors 60 and 52 respectively. Conveyors 64a and 64b carry a series of ‘U’ shaped clamps 66 in opposed facing parallel array along a mid-section under platens 50a. As seen in
The endless conveyors carrying upper and lower platens 50 and 50a respectively and clamps 66 pass through or adjacent to heaters 76 or other non-contact applied-radiation sources such as for example, a microwave source so that, in one embodiment not intended to be limiting, they are maintained at a temperature of approximately 400 degrees Fahrenheit, wherein such a temperature provides for curing of the shaped utensil cut-out in a time of approximately 90 seconds.
As will be noted in
In
It has been experienced that when cutlery is manufactured from a single piece of wooden veneer it has lacked sufficient strength unless the veneer is sliced fairly thickly. However, as the thickness of the veneer increases it is more likely to crack during the molding and curing process. To overcome this, utensil cut-outs 104 and 106, as may be viewed in
Bonding together of the utensil cut-outs is accomplished by the use of a non-toxic thermal setting binder 110, for example corn starch or other similarly non-toxic medium, which is applied to the exposed surface 106a of the lower cut-out 106. Utensil cut-outs are then vertically aligned, placed in contact with each other and inserted into the molds.
The portion of the utensil which comes into contact with food or which is inserted into the mouth may be coated or sealed, for example with an edible wax product as illustrated at 112 on
In an alternative process for producing the cutlery according to the present invention, spoon shapes 112 are stamped out of or otherwise removed from a veneer blank 114 so as to produce a spaced apart parallel array 116 releasably mounted to a common linear member 118 also formed from veneer blank 114. In the preferred embodiment, veneer blank 114 may be used to produce two arrays 116 by stamping the arrays of spoon shapes 112 in opposed facing relations so as to interleave the opposed facing spoon shapes 112. Once an array 116 has been stamped from veneer blank 114, individual spoon shapes or blanks 112 may be removed from member 118 by releasing each spoon blank 112 at a constriction or joint 120.
The spoon blanks 112 once removed from their corresponding arrays 116, may be loaded into a manually operable press or clamp 122. Once loaded into press 122, the spoon blanks 112 form aligned closely adjacent blocks 124 having the outline of a spoon shape. Two such blocks 124a and 124b are illustrated in
A jig 128 is mounted suspended between heads 124a and 124b. Head 124a is slidably journalled in jig 128 so as to translate in direction F into a correspondingly sized cavity, thereby pressing against spoon block 124a. Similarly, head 125b compresses spoon block 124b. The spoon blocks 124a and 124b are held snugly within a correspondingly shaped cavity 128a within and extending longitudinally along the length of jig 128.
With the spoon blocks 124 held rigidly within jig 128, a cutter head 130 may be translated either manually or along sliding setworks (not shown) so as to pass, in the illustrated embodiment which is not intended to be limiting, the three spaced apart cutter head blades 132 into cutting engagement with the top of each spoon block 124 as the blades 132 translate along the length of channel 128b formed in the top of jig 128. Thus as cutter head 130 and the rotating cutter head blades 132 translate in direction G along channel 128b, the individual blades 132 cut the top of each spoon blank 112 within each spoon block 124 so as to form tines 134.
In a preferred embodiment, a pair of laterally opposite reducing heads 136 are also translated along the upper beveled edges of jig 128 so as to trim the exposed edges 134a from the top of each spoon blank 112 within spoon blocks 124 so as to form flat surfaces 134b thereby altering the shape of the end of each spoon blank 112 into a shape resembling that of a fork. The combined utensil then may be used as either a fork or a spoon. Reducing heads 136 may be rotatably mounted within brackets 138 on drive axles 136a.
In an alternative process, in one example of automating the above described manual process for manufacturing the combination fork and spoon, and as better seen in
As spoon blocks 124 are translating on conveyor 138 in direction H they may also be trimmed by the laterally opposite pair of reducing heads 146 (only one of which is shown) so as to form sides 134b on spoon blanks 112. As spoon blocks 124 are nearing reducing heads 146 and saws 144, the spoon blocks are translated into and along correspondingly shaped cavity 148a within elongate rigid jig 148. The upper end of each supporting arm 140 has bevels 140b so as to not interfere with reducing heads 146 as the supporting arms 140 are translated in direction H between the reducing heads and under the saws 144.
Each of supporting arms 140 may be held in place by, for example, a spring plate 150 also mounted to conveyor 138. Supporting arms 140 may be thus formed with the same profile outline as a spoon blank 112 that has been trimmed and sawn, supporting arms 140 and may be connected to conveyor 138 by a neck 152 so as to pass through a corresponding narrow channel 148b between cavity 148a and conveyor belt cavity 148c. Conveyor 138 passes through and along cavity 148c.
As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.
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