A FOOD PATTY WITH IMPROVED VOID STRUCTURE, SHAPE, AND STRENGTH AND METHOD AND APPARATUS FOR FORMING SAID PATTY

Abstract: A patty of food material (35) along with a method and apparatus for forming the patty. The food material (25) is forced through non vertical apertures (76) in a foraminous member (62) into a mold opening (32) in a mold plate (30) to form the patty. One or more agitators bars (90A) may be provided on the upstream side of the foraminous member to dislodge tissue fibers.

Description: A FOOD PATTY WITH IMPROVED VOID STRUCTURE, SHAPE, AND STRENGTH AND METHOD AND APPARATUS FOR FORMING SAID PATTY TECHNICAL FIELD This invention relates to fabrication of a patty of food material. BACKGROUND OF THE INVENTION A novel patty of plastic food material, such as ground meat and the like, as well as novel methods and apparatus for forming the patty, have been developed wherein, inter alia, the food material is forced through cavities or apertures of a foraminous member into a mold to form a patty in which the food material defines interstitial voids for entrapping air and providing retention of cooking juices to promote more rapid and uniform cooking of the patty. Such methods and apparatus are disclosed in the Harry H. Holly U.S. Patent Nos. 4,272,864 and 4,338,702. The U. S. Patent Nos. 4,356,595 and 4,372,008 to Sandberg et al. disclose apparatus for forming a meat patty by forcing ground meat under pressure through a foraminous member which defines a plurality of orifices. In the embodiments illustrated in the above-discussed U. S. Patent Nos. 4,272,864, 4,338,702, 4,356,595, and 4,372,008, each of the cavities, apertures, or orifices defined in the foraminous member are of circular cross section, and each define, for at least part of the thickness of the foraminous member, a cylindrical bore within the foraminous member. The bores are each oriented with the bore longitudinal axis perpendicular to the planar surfaces of the foraminous member and OMPI perpendicular to the plane of the patty mold cavity opening. A patty formed from food material forced through such a foraminous member can have increased void space for trapping air and retaining cooking juices. However, if the discrete extrudate masses of food material in the patty are not also sufficiently cohesive or interlocked, there is a tendency for the patty to break or fall apart when subjected to excessive handling or processing. Accordingly, it would be desirable to provide an improved patty with the desired void structure but also with an improved structural capability for resisting breakage and internal separation. It would also be desirable to provide an improved method and apparatus for making such an improved patty. As is discussed in detail in U.S. Patent Nos. 4,272,864 and 4,338,702, many ground food materials, and especially ground meat, contain string-like tissue fibers which, when the food material is formed into a patty, are distributed within the patty. When such material is initially ground, the tissue fibers are essentially "balled" up, so that their string-like nature is not visibly apparent. However, when the ground material is moved across stationary contacting surfaces in a molding machine during formation of the patty, some of the tissue fibers unwind and may become aligned in the direction of movement of the ground material and/or patty (or in the direction of movement of any surface moving against a stationary patty or mass of ground material) . When the patty is cooked, the tissue fibers contract during the cooking process and cause a shrinkage of the patty in the direction of tissue fiber alignment. The patty does not shrink as much in the direction perpendicular to the aligned tissue fibers so that the resulting patty, though initially formed with a circular shape, assumes a somewhat oval shape after cooking. In contrast, with the patty formed in accordance with the teachings of U. S. Patent Nos. 4,272,864 and 4,338,702, forces tending to unwind the tissue fibers are minimized so that the tissue fibers are generally randomly distributed in one or more of plugs of material and are not as readily unraveled into a generally straight line configuration when the patty surface is subject to friction forces in one direction, as when transferring the patty in a mold transfer plate from one position to another. Since the tissue fibers do not as easily unravel from a random orientation within each plug (or from within a small number of adjacent plugs) , the generally random orientation of the tissue fibers in the patty is generally maintained. While patties formed in accordance with the teachings of U. S. Patent Nos. 4,272,864 and 4,338,702 represent a marked improvement over prior art patties insofar as maintaining a generally circular shape after cooking, nevertheless some slight out of roundness may still occur. This can be caused by tissue fiber alignment in the shear layer that is present at one or both sides of the patty and that is created as the mold plate moves the formed patty to a patty ejecting position. Thus, it would be desirable to provide an improved patty of the type formed by forcing meat through apertures in a foraminous member which would be truly circular upon cooking, and to provide a method and apparatus for forming such a patty. OMPI %fc VATlO When food material that contains tissue fibers, especially meat and the like, is forced through a foraminous member, opposite end portions of a single tissue fiber can be forced into different apertures in the foraminous member. The fibers, being stringy and thin, are not easily severed under the influence of conventional molding pressures. A number of such fibers may be forced against the upstream side of the foraminous member in a manner that tends to plug up the foraminous member apertures. This tendency of tissue fibers to plug up foraminous member apertures was identified by Harry H. Holly and is described in detail in the above-identified U.S. Patent No. 4,272,864 with reference to Figure 23 of that patent. Some of the apparatus and methods disclosed in some of the above-discussed U.S. patents are intended to function, at least with certain types of food material, so as to minimize or prevent the plugging up of the foraminous member with tissue fibers on the upstream side of the foraminous member. However, it would be desirable to be able to form an improved patty (with some or all of the earlier-described characteristics) in a manner that could be employed with a method and apparatus for preventing or minimizing plugging by tissue fibers that are present in the various food materials. Further, it would be beneficial if such a manner of improved patty formation could be effected with a minimum of movement of the food material so as to avoid the undesirable effects of excessive working of the food material. Excessive working of some types of food material, such as ground beef, can make the food material less tender. Finally, it would be advantageous if apparatus could be provided for quickly and easily converting conventional patty molding machines to the improved type of molding machine wherein the food material is forced through a foraminous member and wherein the "conversion" apparatus has the capability for dislodging tissue fibers from the upstream side of the foraminous member so as to avoid or minimize plugging up of the apparatus. SUMMARY OF THE INVENTION An improved patty of food material, as well as a method and apparatus for producing the improved patty, are disclosed. The patty has less of a tendency to break apart before and after cooking. In one disclosed form, it also has less of a tendency to be non-circular in shape after cooking. The apparatus disclosed herein includes a foraminous member having a plurality of apertures therein which establish communication between an upstream side of the foraminous member and a mold opening defined by suitable mold parts on the downstream side of the foraminous member. At least some of the foraminous member apertures each have at least a portion of the aperture that is adjacent the mold opening oriented so as to discharge food material into the mold opening in a direction that is not perpendicular to the plane of the mold opening (i.e., the plane of the mold plate). The food material is forced through the apertures in the foraminous member as extrudate masses (e.g., plugs or strands) into the mold opening. The extrudate masses tend to overlap, interweave, or knit together in a manner that 1) provides interstitial voids within the patty and 2) functions to hold the patty together. Some of the extrudate masses also impinge against, and are deflected by, the peripheral and bottom walls of the mold opening as they fill the mold opening. The deflected portions further interweave to produce a patty that has increased resistance to breaking apart. In a preferred embodiment, a patty is formed which assumes an oval shape upon being ejected from the patty forming apparatus, with the larger patty dimension being in the direction of tissue fiber alignment in the patty shear layer, so that upon cooking and shrinkage of the aligned tissue fibers the patty will assume a round or circular shape. While the present invention has primary utility in the production of hamburger patties that are traditionally generally circular in shape after cooking, the invention has applicability to the production of other types of patties, such as sausage patties formed of chopped rather than ground meat materials. Also, the present invention has applicability to the formation of patties having shapes other than generally circular or round. In a one disclosed embodiment, the foraminous member apertures may be all generally oblique cylinders which are parallel and angled in the same direction. As pressure is continuously applied, and as the mold opening is filled, the extrudate masses of material accummulate, and it is possible for many of the masses to also be packed together in a somewhat shingled, as well as interwoven, fashion. Since the mold opening is filled with a component of pressure in one direction, say in the front-to-rear direction, the extrudate masses apply more pressure against the front and rear portions of the peripheral wall of the mold opening than against the side portions of the peripheral wall of the mold opening. When a patty formed by the method and apparatus described in the preceding paragraph is ejected from the mold opening, or otherwise freed from the constraint of the peripheral wall of the mold opening, the release of the stored-up pressure will cause the patty to expand more in a front-to-rear direction than in a side-to-side direction. When the filled mold parts are moved in a front-to-rear or rear-to-front direction from the patty molding position to the patty ejection position, a shear layer is formed at one or both sides of the patty and contains tissue fibers that are generally aligned in that direction of movement. When such a patty is allowed to expand into an elongated shape upon ejection from the mold plate and then cooked, the aligned tissue fibers will shrink and cause the cooked patty to assume a true circular shape. The novel method and apparatus disclosed herein for forming an improved patty can be employed in conjunction with a system for preventing the apparatus from plugging up with tissue fibers. At least one agitator bar can be provided for movement relative to, and adjacent, the upstream side of the foraminous member to dislodge tissue fibers. In a preferred form, two such bars are provided, and one bar is moved along a straight line path that is at an angle to the straight line path of movement of the other agitator bar. Moreover, both of the agitator bars are also preferably biased against the upstream side of the foraminous member. In any case, the novel foraminous member structure disclosed herein may be readily provided _ OMPI with or without one or more agitating bars as part of a subassembly for "converting" existing molding machines to an improved apparatus. Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention, from the claims,.and from the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings forming part of the specification, and in which like numerals are employed to designate like parts throughout the same. Figure 1 is a fragmentary, partial cross-sectional view of a portion of a machine for molding a patty of plastic food material which contains tissue fibers; Figure 2 is a top, perspective view of a subassembly apparatus for converting the machine illustrated in Figure 1 to an improved patty molding apparatus; Figure 3 is an exploded, bottom, perspective view of the subassembly apparatus of Figure 2; Figure 4 is a perspective view of each of the two agitator bars of the subassembly apparatus shown in Figure 3; Figure•5 is a top plan view of the agitator bar receiving trays connected to a pair of guide rods as employed in the subassembly apparatus illustrated in Figure 3; Figure 6 is an enlarged, fragmentary, cross-sectional view similar to Figure 1, but showing the subassembly of Figure 3 mounted in the machine of Figure 1 with the machine's mold plate being illustrated in the patty molding position; Figure 7 is a view similar to Figure 6, but showing the mold plate in the patty ejecting position; Figure 8 is a perspective view of the upstream side of a second embodiment of a foraminous member forming part of the subassembly apparatus and showing two agitator bars disposed adjacent the upstream side of the foraminous member; Figure 9 is a greatly enlarged, fragmentary, plan view of a portion of the upstream side of the foraminous member illustrated in Figure 8 and showing the two agitator bars adjacent the foraminous member; Figure 10 is a even more greatly enlarged, fragmentary, cross-sectional view taken generally along the plane 10-10 in Figure 9; Figure 11 is a perspective view of a modified form of the two agitator bars which can be used in the subassembly apparatus as a third embodiment; Figure 12 is a greatly enlarged, fragmentary, cross-sectional view of the modified agitator bars of Figure 11 shown in the subassembly apparatus mounted in a molding machine; Figure 13 is a perspective view of a another modified form of the two agitator bars which can be used in the subassembly apparatus as a fourth embodiment; Figure 14 is a greatly enlarged, fragmentary, cross-sectional view of the modified agitator bars of Figure 13 shown in the subassembly apparatus mounted in a molding machine; Figure 15 is a plan view of the upstream side of a further modification of a foraminous member forming part of the subassembly apparatus as a fifth embodiment; OMPI W1PO Figure 16 is an exploded perspective view of molding machine apparatus shown in a simplified, partly diagrammatic manner to illustrate the concept of biasing an agitator bar against a foraminous member; Figure 17 is a fragmentary, exploded, perspective view of some of the components of a molding machine to illustrate another method and apparatus for biasing an agitator bar against a foraminous member; Figure 18 is a greatly enlarged, fragmentary, cross-sectional view taken generally along the plane 18-18 of Figure 17 and rotated 90°; Figure 19 is a fragmentary, exploded, perspective view of components of a molding machine illustrated in simplified, partly diagrammatic form to show yet another method and apparatus for biasing an agitator bar against a foraminous member; Figure 20 is an end view, partly fragmentary, of the apparatus of Figure 19 in a fully assembled condition and taken along the plane 20-20 in Figure 19; Figure 21 is a diagrammatic view of an alternate path of movement of an agitator bar relative to a foraminous member; Figure 22 is a simplified diagrammatic view of still another alternate path of movement of an agitator bar relative to a foraminous member; Figures 23, 24, and 25 are schematic top plan views of a hamburger patty and illustrate, respectively, the patty in the molded condition, the ejected condition, and the cooked condition; Figure 26 is an enlarged, cross-sectional view of the patty taken generally along the plane 26-26 in Figure 24; and Figure 27 is a perspective view of the patty illustrated in Figures 24 and 26. DESCRIPTION OF THE PREFERRED EMBODIMENT While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail preferred features of the invention. It will be understood, however, that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the specific form of the combination of features that are illustrated and described. The precise shapes and sizes of the components herein described are not essential unless otherwise indicated. It will be understood that reference is made herein, aηd in the claims, to various terms such as "food material," "tissue," "fiber," and "plastic." Each such term is used in a sense that may have a denotation not necessarily identical to the denotation of the term as used in the technical fields of chemistry, medicine, rheology, and the like. Rather, such terms are used herein to generally describe various substances exhibiting the characteristics discussed herein and to which the present invention is directed. For ease of description, the operation of apparatus disclosed herein is described in a normal operating position and terms such as upper, lower, horizontal, etc. will be used with reference to the normal operating position. It will be understood, however, that the apparatus may be manufactured, stored, transported, and sold in an orientation other than the normal operating position described. The apparatus disclosed herein has certain conventional mechanisms, including drive mechanisms, food material pressurizing mechanisms, food material receiving structures, and control mechanisms, the details of which, though not fully illustrated or described, will be apparent to those having skill in the art and an understanding of the necessary functions of such mechanisms. The apparatus disclosed herein may be constructed of a variety of materials. The choice of material in some cases is dependent upon a particular application involved and other variables, as those skilled in the art will appreciate. CONVENTIONAL MOLDING MACHINE Part of one basic type of conventional machine 20 for forming or molding a patty of food material which may contain tissue fibers, such as are found in pieces of meat and the like) is illustrated in Figure 1. Machines of this type are manufactured by, among others, Hollymatiσ Corporation, 600 East Plainfield Road, Countryside, Illinois, 60525, U.S.A. Machines of this type can be adapted to use the subassembly 60 (Figure 2) and alternate embodiments described hereinafter. The embodiments of the subassembly 60 illustrated herein are especially designed for being used with ("converting") molding apparatus or machines marketed by Hollymatic Corporation in the United States of America under the designations "Hollymatic 500" and "Hollymatic 580". Although the specific embodiments of the novel processes and subassembly apparatus disclosed herein are adapted for use with, and are illustrated herein as incorporated in, the above-identified conventional Hollymatic Corporation machines, it is to be realized that the principles of the present invention may also be used, with appropriate modifications, in other patty molding machines of the same general type as the Hollymatic Corporation machines wherein food material is forced under pressure into a mold opening to form a patty. As illustrated in Figure 1, the machine 20 includes a lower portion 22 defining part of a first pressurizable feed chamber or food material reservoir 24. The top of the reservoir 24 is covered and defined by a cover plate 26. The cover plate 26 defines a feed aperture 28 through which pressurized food material 25 is forced. Depending on the machine design, the feed aperture 28 may be located as illustrated to supply food material 25 to the center portion of the ultimately formed patty 35 or may alternatively be located to supply the food material 25 to a region at or near the periphery of the patty 35. The food material 25 is moved or conveyed forward in the chamber 24 and upwardly through the aperture 28 by a mechanism capable of pressurizing the material 25 within the chamber or reservoir 24. Though such a mechanism is not illustrated in the present disclosure, any number of suitable conventional mechanisms may be employed. An example of one such suitable mechanism is that disclosed and illustrated in the U.S. Patent No. 3,293,688. In the above-discussed Hollymatic 500 and Hollymatic 580 molding machines, the pressurizing mechanism comprises a reciprocating compression blade and pin plate of conventional design known to those skilled in the art and generally described in the above-discussed U.S. Patent Nos. 4,272,864 and 4,338,702. However, any suitable feed mechanism may be used with the molding machine 20 and subassembly OMPI 60. The specific feed mechanism construction per se forms no part of the present invention. A mold plate 30 is slidably disposed on top of the food material reservoir cover plate 26. The mold plate 30 has a mold opening 32 which defines at least a peripheral portion of a mold cavity having the shape of the patty 35 that is to be ultimately molded. The mold plate 30 is adapted to be moved between a patty molding position wherein the mold opening 32 receives the pressurized food material 25 (as illustrated in Figure 1) and a patty ejecting position (to the left of the mold plate position illustrated in Figure 1) wherein the mold opening 32 is spaced away from the patty molding position and is generally exposed to permit ejection of the molded patty 35 from the mold plate 30. Typically, the formed patty 35 is automatically ejected from the mold plate 30 by a suitable patty ejecting mechanism represented generally by reference numeral 38. The patty ejecting mechanism 38 may be of any suitable conventional type and may include a disc-like or cup-like member 40 mounted to a drive rod 42. The ejecting mechanism 38 is timed to intermittently reciprocate in the vertical direction to eject the formed patty 35 when the mold plate 30 periodically moves a molded patty 35 into the patty ejecting position. The construction and operation of the patty ejecting mechanism 38 per se forms no part of the present invention. An upper guide plate 50 is fixed to the cover plate 26 at a spaced location therefrom so that the plates 50 and 26 together define a guideway between which the mold plate 30 is disposed and along which the mold plate 30 is reciprocated. As best illustrated in Figure 1, the cover plate 26, the upper guide plate 50, and the mold plate 30 all function together as mold parts defining the mold cavity. Specifically, the cover plate 26 defines a portion of the bottom of the mold cavity, the mold plate 30 defines the peripheral or vertical side portion of the mold cavity, and the upper guide plate 50 defines the top surface of the mold cavity. Plastic food material, which may be meat that has been chopped, ground, or otherwise reduced to relatively small pieces, can be conveniently formed into a patty with the general type of machine 20 illustrated in Figure 1. However, for the various reasons set forth in the above-discussed U.S. Patent Nos. 4,272,864 and 4,338,702, such a patty, if made from ground beef, can have a number of undesirable characteristics. Specifically, such a patty may have many of the tissue fibers oriented and aligned in generally parallel lines. The aligned tissue fibers contract during the cooking process and cause a shrinkage of the patty in the alignment direction. Further, patties made with such conventional apparatus are not as porous as would be desired. Such a patty, being more dense than desired, has less of a capability for entrapping air and retaining cooking juices. Consequently, the cooked patty does not have the degree of porosity and juiciness that would be desired. Formation of a patty with a foraminous member according to the general principles of the above-discussed patent Nos. 4,272,864 and 4,338,702 can provide an improved patty that does not suffer from the above-described deficiencies. Moreover, it has now been determined that 1) the patty can be even further improved with respect to strength and shape as described hereinafter and 2) a less complex . assembly can be provided which enables conventional machines to form such an improved patty. To this end, a conventional patty forming machine 20 of the type generally illustrated in Figure 1 may be readily converted, according to the principles described hereinafter, to an improved machine. Such an improved machine effects the formation of the an improved patty with the use of a foraminous member according to a novel process disclosed herein and may also include novel features for reducing the tendency of the foraminous member to plug up with tissue fibers. FIRST EMBODIMENT The first embodiment of the subassembly 60 illustrated in Figure 2 may be conveniently used for the above-described modification of a conventional molding machine. The subassembly 60 includes a top plate or foraminous member 62 and underlying plates 64 and 66. The bottom underlying plate 66 is adapted to be disposed on top of the cover plate 26 of the machine 20 as best illustrated in Figure 6. The upper plate or member 62 is a foraminous member defining a foraminous region 70 which may be a separate insert or which may be formed integrally with the plate 62 as illustrated. In any case, the bottom of the foraminous member 62 defines an upstream side 72 (Figure 6) , which may be a generally flat and planar surface as illustrated, and the top of the member 62 defines a downstream side 74 (Figures 3 and 6) . As best illustrated in Figures 2 and 3, the foraminous member 62 has a plurality of apertures 76 extending through the foraminous member between the upstream side 72 and the downstream side 74. The apertures 76 define an array of openings at the upstream side 72 which are preferably, though not necessarily, arranged in a first set of spaced-apart parallel rows and in a second set of space-apart parallel rows. The rows of aperture openings of the first set are oriented at an acute angle relative to the rows of the second set. This is illustrated in Figure 3 wherein a line L, has been drawn through a row of the first set of spaced-apart parallel rows of openings and wherein a line L-. has been drawn through a row of the a second set of spaced-apart parallel rows of openings, in the preferred embodiment, the angle alpha between the two lines L, and L~ is an acute angle (e.g., about 60 degrees) . In the first embodiment of the subassembly illustrated in Figure 3, at least two agitator bars 90A and 90B are disposed adjacent the upstream side 72 of the foraminous member 62 for reciprocative movement along the upstream side 72. As best illustrated in Figures 3 and 4, the agitator bar 90A includes a plurality of spaced-apart, angled, teeth 92A oriented with at least one tooth 92A between two adjacent rows of the first set of parallel rows of openings defined in the upstream side 72 by the apertures 76. The other of the agitator bars, bar 90B, similarily includes a plurality of spaced-apart, angled teeth 92B oriented with at least one tooth 92B between two adjacent rows of the second set of parallel rows of openings defined in the upstream side 72 by the apertures 76. A novel construction is provided for guiding the agitator bars 90A and 90B in the desired paths of movement relative to the foraminous member 62. Specifically, the foraminous member upstream side 72 two straight guide slots, guide slot 94A and 94B. The guide slots 94A and 94B are oriented at an angle to each other which is equal to the angle alpha discussed above. Thus, guide slot 94A is parallel to the first set of parallel rows of openings defined in the upstream side 72 by the apertures 76. Similarily, guide slot 94B is parallel to the second set of parallel rows of openings defined in the upstream side 72 by the apertures 76. The agitator bar 90A has a projecting guide member 95A for being received in the guide slot 94A. Similarily, the agitator bar 90B has a projecting guide member 95B for being received in the guide slot 94B. Thus, each guide slot will function to define the locus of motion of its associated agitator bar. That locus of motion lies at an angle relative to the locus of motion of the reciprocating mold plate 30 (e.g., if angle alpha is about 60 degrees, then the relative angle between these loci of motion would be about 30 degrees) . The agitator bars 90A and 90B are supported and maintained in a plane that is generally parallel to the plane of movement of mold plate 30. This support is provided by a support frame 96 which comprises two channel-like trays 97A and 97B (Figure 5) that are connected between two drive rods 98. The drive rods 98 are slidably mounted in the plates 64 and 66 as illustrated in Figures 2 and 6. As best illustrated in Figures 5 and 6, each tray 97A and 97B defines a straight channel opening toward the upstream side 72 of the foraminous member 62 with the length of the channel oriented normal to the straight line locus of motion of the mold plate 30. The channel defined by each tray 97A and 97B is sized to receive one of the agitator bars 90A and OMPI 90B, respectively, in a sliding relationship. The channel in each tray 97A and 97B is longer than the length of the associated agitator bar 90A or 90B so as to accommodate side-to-side reciprocative movement of the agitator bar. In the first embodiment illustrated, as well as in the other embodiments, the foraminous member apertures 76 may be drilled in the foraminous member 62 to form generally cylindrical surfaces or bores. Bores or apertures 76 with a diameter ranging between about 2.4 mm. and about 3.6 mm. have been found to function well when preparing patties of raw ground beef. If desired, each aperture 76 may have an enlarged counterbore (not illustrated) that opens to the upstream side 72 of the foraminous member 62. Each aperture 76 may also have a non-circular cross section which may vary in size and shape along the length of the aperture. As can be best seen in Figures 6 and 7, the bores or aperture 76 are preferably drilled at an angle with respect to the foraminous member surfaces 72 and 74. The apertures 76 are illustrated as being disposed at an angle with respect to the surfaces 72 and 74 of about 45 degrees. An angle of about 26 degrees has also been found to work well. However, the present invention contemplates that other orientations may be used. For example, not all of the apertures (bores) 76 need be oriented as illustrated at the same, uniform angle with the axes of all of the apertures (bores) 76 lying in parallel planes. Some apertures (bores) 76 may be oriented with their longitudinal axes skewed in other directions and at other angles. Indeed, some of the apertures 76 may be vertically oriented (i.e., not inclined with respect to the foraminous member surfaces 72 and 74) . The apertures need not necessarily have the shape of a cylinder or prism. Instead, one or more apertures may have a corkscrew or other shape which would guide the food material in a non-linear path through the foraminous member 62. As described in detail hereinafter, the use of non-vertical apertures 76, regardless of cross-section configuration, can result in an improved molded patty having characteristics found to be highly desirable, especially when the patty is molded from raw ground meat which is intended for subsequent cooking. The term "non-vertical aperture" as used herein means an aperture having at least a portion of the aperture that is adjacent the mold opening 32 oriented so as discharge the food material into the mold opening 32 in a direction that is not perpendicular to the plane of the mold opening (i.e., the plane of movement of the mold plate 30.) As illustrated in Figures 6 and 7, the plates 64 and 66 define an interior chamber 110 on the upstream side of the foraminous member 62. The agitator bars 90A and 90B, the frame 96, and portions of the drive rods 98 are received within this chamber 110. The drive rods 98 are slidably received at the ends of the chamber 110 between the plates 64 and 66. The drive rods 98 are reciprocated by a novel connection with the conventional mechanism employed for reciprocating the mold plate 30. Specifically, in the above-discussed Hollymatic 500 and Hollymatic 580 machines, the mold plate is reciprocated by a shuttle mechanism which includes a pair of shuttle bars 136 (Figures 6-8) . One shuttle bar 136 is located along one side of the machine and other shuttle bar 136 being located along the other side of the machine. A shuttle assembly 138 is slidably disposed on the shuttle bars 136. The shuttle assembly 138 is connected to a suitable linkage system (not illustrated) driven by a suitable conventional mechanism (not illustrated) for reciprocating the shuttle assembly 138 at the desired frequency and stroke length along the shuttle bars 136. The shuttle assembly 138 includes a drive pin 140 which, in the conventional (and unmodified) Hollymatic 500 and 580 machines, is received in a bore 142 (Figure 6) in the overlying mold plate 30. When the Hollymatic 500 and 580 machines are modified to accommodate the novel subassembly apparatus 60 discussed above, the existing pin 140 serves as a means for mounting a longer pin 144. Specifically, the longer pin 144 includes an enlarged base member 146 (Figure 6) with an aperture in which is received the pin 140. The longer pin 144 then projects upwardly into the bore 142 of the mold plate 30. Each pin base member 146 is adapted to be engaged with a forward end 120 of a drive rod 98 (Figures 2, 6, and 7) . The forward end 120 of each drive rod 98 defines an elongate slot 122 in which the base member 146 is slidably received. The Hollymatic 500 and 580 machine have a mold plate stroke length of about 20.32 cm. When the novel subassembly 60 is incorporated in such Hollymatic machines, the elongate slot 122 in the end 120 of each agitator bar drive rod 98 is about 10.16 cm. in length. The relationship between mold .plate stroke length and the length of each drive rod slot 122 thus permits a lost motion action to occur. Specifically, when the mold plate 30 is initially moved from the extended, patty ejecting position (Figure 7) toward the patty molding position (Figure 6) , the pin base member 146 does not engage the end of the slot 122 (the right-hand end) until a predetermined amount of mold plate movement has occurred (about 10.16 cm. in the Hollymatic 500 and 580 machines) . Similarly, when the mold plate 30 is initially moved from the patty molding position (Figure 6) to the patty ejecting position (Figure 7) , the pin base member 146 does not engage the other end of the slot 122 (the left-hand end) until the mold plate 30 has moved away from the patty molding position a predetermined amount (about 10.16 cm. Hollymatic 500 and 580 machines) . If the novel subassembly 60 described above is incorporated in patty molding machines other than the Hollymatic 500 and 580 machines discussed above, then the mechanism for reciprocating the agitator bar drive rods 98 will, of course, be modified somewhat from that illustrated. Preferably, however, the agitator bar drive rods 98 will be connected, via a suitable lost motion linkage, to the mechanism for reciprocating the mold plate. Of course, the agitator bar drive rods 98 could be reciprocated by means independent of the means for reciprocating the mold plate. In any case, the drive rods 98 are reciprocated in the directions parallel to the directions of reciprocation of the mold plate 30. However, owing to the angled orientation of the guide slots 94A and 94B in the foraminous member 62 and owing to the agitator bar members 95A and 95B . received therein, it is not possible for the agitator bars 90A and 90B to be moved in a straight line path parallel to the straight line path of reciprocation of the drive rods 98 and mold plate 30. The agitator bar members 95A and 95B, and hence the bars, must necessarily follow the angled paths defined by the guide slots 94A and 94B. Movement of the frame 96 causes the agitator bars 90A and 90B to be driven along the foraminous member upstream side 72. As the frame 96 is moved along the cavity 110 by the drive rods 98, the agitator bars 90A and 90B are each also displaced in a direction perpendicular to the straight line path of movement of the drive rods 98 and mold plate 30. This movement is accommodated by the elongate channels of the frame trays 97A and 97B which permit the agitator bars to slide transversely in the trays across the foraminous member upstream side 72 in directions perpendicular to the straight line path of movement of the mold plate 30. As a result, the agitator bar 90A moves along a path parallel to the guide slot 94A and parallel to the first set of parallel rows of. openings defined in the upstream side 72 by the apertures 76. Similarily, the agitator bar 90B moves along a path parallel to the guide slot 94B and parallel to the second set of parallel rows of openings defined in the upstream side 72 by the apertures 76. Between each pair of adjacent rows of aperture openings there is a tooth of one of the agitator bars. Thus, each such tooth moves along a path that is parallel to, and between, two rows of aperture openings so as to at least agitate the tissue fibers in a manner explained in more detail hereinafter. Most of the apertures 76 will each be subjected to the sweeping or agitating motion of a pair of spaced-apart teeth 92A of bar 90A on opposite sides of the aperture. Most of the apertures 76 will be similarly subjected to the sweeping or agitating OMPI motion of a pair of spaced-apart teeth 92B of bar 90B on the other two sides. With the bar 90A moving forward along a path at an angle of 60° relative to path of movement of the bar 90B, each aperture 76 will circumscribed by four straight line paths of travel of the four teeth, and the circumscribing paths will define a parallelogram or rhombus around the aperture. Thus the sweeping or agitating action of the teeth is effected around the entire periphery of the aperture. In the embodiment shown in Figures 1-6, the agitator bars 90A and 90B are each spaced slightly away from the foraminous member upstream side 72. However, in many instances each agitator bar may be advantageously positioned in direct contact with the foraminous member upstream side 72. This may be effected with a substantially "zero" clearance construction or by actually biasing the bars 90A and 90B to urge the teeth into direct contact with the upstream side 72 of the foraminous member 62. This is described in detail hereinafter with reference to alternate embodiments of the agitator bar illustrated in Figures 11-14. In operation, the mold plate 30 is moved to the patty molding position (Figure 6) so as to dispose the mold opening 32 adjacent the downstream side 74 of the foraminous member 62. In this position the agitator bars 90A and 90B are each at one end of their path of movement (the right-hand end of the chamber 110 as illustrated in Figure 6)- During the time that the mold plate 30 is moved from the patty ejecting position to the patty molding position illustrated in Figure 6, the food material is pressurized and is forced through the aperture 28 of the cover plate 26 and into the JfclAi "W-fό " - chamber 110. Initially, when the solid end portion of the mold plate 30 (the right-hand end portion of the mold plate as illustrated in Figure 6) is moving over the foraminous member 62, the food material fills the apertures 76 of the foraminous member 62 and is compressed therein against the overlying mold plate 30 which is sliding therepast. However, as the mold opening 32 begins to move over the foraminous member 62, the food material begins to be forced into the mold opening 32 (initially at the left-hand portion of the foraminous region 70 as viewed in Figure 6) . The food material is discharged under pressure into the mold opening 32 as the leading edge of the mold opening 32 continues to uncover more apertures 76. Finally, when the mold plate 30 has been moved to the fully retracted (patty molding) position illustrated in Figure 6, the maximum number of foraminous member apertures 76 have been uncovered and these apertures 76 function to admit pressurized food material into the entire mold opening 32 for completion of the patty molding step. (If desired, the food material pressurizing mechanism (not illustrated) may be only periodically operated so as to effect pressurization of the food material only when some or all of the apertures 76 are uncovered.) As the pressurized food material flows through the apertures 76 of the foraminous member 62 into the mold opening 32, discrete extrudate masses of material 160 (Figure 7) are formed within, or by, the apertures 76. Because of the inclination of the apertures 76, the extrudate masses 160 enter the mold opening with an upward component of movement, as well as with a component of movement lengthwise of the mold plate 30. As a mass 160 enters the mold opening 32, there may be some amount of circumferential expansion of each extrudate mass 160. Further, the extrudate masses 160 may not all maintain the same direction of movement once they have entered the mold opening 32. Depending on, inter alia, 1) the spacing between the apertures 76, 2) the shape and size of each aperture 76, 3) the orientation of each aperture 76, and 4) the pressure with which the food material is forced through the apertures 76, the extrudate masses 160 in the mold opening 32 will assume various degrees of relative non-alignment and random orientation. Indeed, the extrudate masses 160 become interwoven or knitted together. This functions to increase the strength of the patty 35. The patty 35 will have less of a tendency to break or fall apart before, during, and after cooking. Such interweaving may be further aided- by the interaction between the extrudate masses 160 and the air pressure in the mold opening 32. As the extrudate masses enter the mold opening 32, the air in the mold opening is necessarily compressed in a continuously decreasing volume. Although conventional means are typically provided for relieving the resulting increased pressure in the mold opening, the increased transient air pressure may provide some resistance to the incoming flow of food material which may further deflect the extrudate masses and enhance the interweaving effect. Portions of the masses 160 also ultimately turn in different directions as they impinge upon the mold cavity surfaces. The mold cavity surfaces are defined by 1) the upper plate 50, 2) the vertical side walls of the mold plate 30 defining the mold cavity 32, and 3) the portions of the downstream OM-l_ surface 74 of the foraminous member 62 which lay between the apertures 76. Owing to the twisting, turning, and interweaving of the extrudate masses 160 in the mold cavity 32, the extrudate masses 160 form a patty which contains a significant amount of voids or air spaces and which has a relatively high degree of porosity. Compressed air trapped in the void spaces may also cause some desirable expansion of the patty after it is ejected from the mold -- thus contributing to the formation of an even less dense patty. The type of patty described above, wherein the extrudate masses 160 are interwoven to form a porous patty, has been satisfactorily molded with the apparatus of the present invention employing a foraminous member 62 having a thickness of about 9.5 mm. The apertures 76 were cylindrical bores angled at about 26 degrees in parallel planes and each aperture 76 had a diameter of about 3 mm. The distance between center lines of adjacent apertures 76 in each row was about 9.5 mm. The mold opening 32 was about 101.6 mm and the thickness of the mold plate 30 was about 19.1 mm. If most of the inclined apertures 76 are angled in the same direction and are relatively close together in relation to the size of each aperture, some portion of the extrudate masses 160 entering the mold opening 32 will each tend to be generally - oriented, at least for a portion of their length, at an angle in the mold opening 32. Once they are free of the constraint of the walls of apertures 76, the discrete masses of material 160 may expand circumferentially somewhat and surface portions of adjacent masses will ultimately come into contact. Portions of the masses 160 will also ultimately impinge at an angle upon the mold cavity surface defined by the upper plate 50 and will be deflected downwardly by such surface and will flow toward the left-hand side of cavity 32, as viewed in Figure 1. As the mold opening is filled, more pressure is applied to the left and right peripheral edges of the mold opening (as viewed in Figure 6) than to the sides thereof due to the application of the molding pressure through the inclined apertures 76. As a result, assuming that the mold opening 32 is circular, when the patty 35 is ejected from the mold opening (compare Figure 23 to Figure 24) the stored-up pressure will cause the patty to expand in the direction (P* in Figure 10) in which pressure is greater. This will produce an elongated patty 35a. It has been found that for a patty that is nominally 4" in diameter (dimension "P" in Figure 23) , the patty will expand after ejection from the mold opening to about 4 1/4" to 4 3/16" (dimension P* in Figure 24) . The patty in the perpendicular dimension (P" in Figure 24) may contract somewhat when the patty is ejected from the mold opening, but this dimension will be essentially the same as the diameter of the mold opening. It will be readily appreciated that because of the expansion of the patty 35a after ejection from the mold opening, an extremely porous product is produced. Such a product may be cooked more quickly, and as a result may retain more of the natural juices thereby providing enhanced flavor and texture. Also, for reasons explained hereinafter, the elongated patty 35a formed from meat containing tissue fibers will tend to cook into a circular shape as shown in Figure 25 (for the "cooked" patty 35b) if a shear layer is formed across one or both sides of the patty as described hereinafter. The discrete masses of food material 160 passing into the mold cavity through closely spaced, inclined apertures 76 may also curl in a lengthwise direction, moving under one another, so that a shingled interweaving of the extrudate masses is produced, as is shown in Figures 26 and 27. In any case, the food material is eventually forced through the foraminous member 62 so that the discrete extrudate masses 160 in the mold cavity above the foraminous member 62 together define a packed array forming the patty 35. Voids or air spaces exist between the packed extrudate masses 160 in the patty 35 to give the patty a relatively high degree of porosity even as compared to the greatly improved patties produced in accordance with the teachings of U.S. Patent Nos. 4,272,864 and 4,338,702. The resulting patty has a grinder-like texture, a result which has heretofore not been possible for a thin patty. It is to be realized that the illustrations of the patty in Figures 26 and 27 are greatly simplified and that the alignment configuration of the extrudate masses 160 is exaggerated for descriptive purposes. It is also to be realized that the shingled interweaving structure illustrated for the patty in Figures 26 and 27 can be altered by, among other things, changing the spacing between the foraminous member apertures 76. In addition, if the apertures 76 are not all inclined in the same direction, the intertwining character of the extrudate mass structure can be considerably altered. Depending upon the precise shape of each aperture, the orientation of each aperture, the spacing between the apertures, the size of each aperture, the size of the mold opening, and the pressure at which food material is forced through the foraminous member, a different, and in some cases, increased interweaving or intertwining structure can be produced. A patty with increased interweaving could have little or none of the "shingled" structure illustrated in Figures 26 and 27. Of course, with a patty that does not have extrudate masses 160 in a substantially angled configuration as illustrated in Figures 26 and 27, there may be substantially less stored-up pressure in the patty, and there will be substantially less or no unidirectional elongation of the patty when it is ejected from the mold opening. However, depending upon the food material injection pressure, upon relative spacing between the apertures, and upon the size of the mold opening, such a patty may have stored-up pressure which will cause the patty to expand somewhat in generally all peripheral directions after the patty is ejected from the mold opening. In any case, it has been found that the formation of a patty with food material extruded through "non-vertical apertures" will produce an improved molded patty having a desirable void structure for retaining cooking juices and having increased structural strength so that the patty has less of a tendancy to break apart before, during, and after cooking. During the process of forcing the food material against and through the foraminous member 62, there may be an initial tendancy for some of the apertures 76 to become partially plugged with tissue fibers or other pieces of food material. For example, some tissue fibers and other pieces of food material may initially extend across the upstream side of the foraminous member 62 between adjacent apertures 76 in a row of apertures. However, as will next be explained in detail, these fibers are agitated by the moving agitator bars 90A and 90B. This prevents an accummulation of tissue fibers on the foraminous member upstream side 72 that might otherwise eventually plug up the apparatus. When the machine drive pins 144 first move to drive the mold plate 30 to the patty molding position (Figure 4) , the drive rods 98 are not initially engaged by the pins base members 146. After some predetermined initial movement of the mold plate 30 away from the patty ejecting position, the base members 146 push the drive rods 98 inwardly (to the right as viewed in Figure 6) . This causes the agitator bars 90A and 90B to sweep across the upstream side of the foraminous member. As the agitator bars 90A and 90B sweep across the upstream side of the foraminous member 62, the tissue fibers are sufficiently agitated that many become dislodged and oriented in other positions. Many of the tissue fibers become oriented in a way that permits them to pass through the apertures 76. After the mold opening 32 is filled, the mold plate 30 begins to move back to the patty ejecting position (Figure 7) . After a predetermined initial movement of the mold plate 30, the agitator bars 90A and 90B again to sweep across the upstream side 72 of the foraminous member 62 (to the left as viewed in Figure 7) . When the mold plate 30 reaches the patty ejecting position (Figure 7) , the agitator bars 90A and 90B are also at the end of their return strokes and the patty 35 is ejected. Not all of the tissue fibers that may be lodged on the upstream side of the foraminous member 62 will necessarily be dislodged by one sweep of the agitator bars 90A and 90B across the foraminous member 62. However, each stroke of the agitator bars 90A and 90B with the mold plate 30 provides additional agitation which dislodges tissue fibers. Indeed, the periodic reciprocation of the agitator bars 90A and 90B across the foraminous member 62 with each molding cycle functions to continuously effect a dislodging of the tissue fibers. A tissue fiber that does not get dislodged during one sweep of the bars 90A and 90B will ultimately get dislodged during one of the subsequent sweeps of the agitator bars. In the embodiment illustrated in Figures 2-7, the teeth 92A and 92B of the agitator bars 90A and 9OB, respectively, do not contact or slide against the foraminous member 62. However, it has been found that under certain operating conditions and with certain types of food material, including raw ground meat, it is desirable for the teeth 92A and 92B to be in sliding contact with the upstream side 72 of the foraminous member. This can be accomplished by constructing the subassembly 60 so that there is substantially no clearance between the agitator bar teeth and the foraminous member 62 or by specifically biasing the agitator bars against the foraminous member upstream side 72. This provides an improved action with respect to preventing tissue fiber build-up on the foraminous member upstream side 72. Means for biasing the agitator bar teeth against the foraminous member are described in detail hereinafter with respect to the modified embodiments illustrated Figures 11-14. OMPI As pointed out in the above-discussed U.S. Patent Nos. 4,272,864 and 4,338,702, it is desirable in many cases to provide a patty having a shear layer of somewhat dense food material on one or both of the top and bottom surfaces of the patty. The layer of dense food material is preferably about 0.4 mm. thick, although a shear layer of a greater or lesser thickness may be provided. Preferably, the shear layer is thick enough to aid in holding the formed patty together and to reduce the tendency of the patty to break apart during handling prior to, during, and after cooking. It is believed that such a layer also functions to trap the air and vapors in the interstitial voids below the layer during cooking to thereby promote more rapid and more uniform cooking of the patty and to thereby aid in retention of the cooking juices. The above-described shear layer on one or both of the top and bottom surfaces of the patty can be formed with the apparatus of the present invention (but the thin shear layer is not visible in the patty 35 in Figure 7) . This is effected by providing a certain amount of clearance between the top surface of the mold plate 30 and the bottom surface of the upper plate 50 and/or between the bottom surface of the mold plate 30 and the top surface of the cover plate 26. If the clearance between the mold plate and the overlying or underlying plate is sufficient, then the plastic food material trapped within this clearance region in the mold area will be subject to frictional forces when the mold plate is moved from the patty molding position to the patty ejecting position. As the mold plate is so moved, the plastic food material in the clearance region is forced ^ against the surface of the formed patty. In order to insure that the shear layer is properly formed and possesses sufficient structural integrity, the inven¬ tor of the present invention has determined that it is desirable to arrange the rows of apertures 76 at a common angle skewed relative to the straight line path of motion of the reciprocating mold plate 30. As il¬ lustrated in Figure 3, the angle (equal to one-half of angle alpha) may be about 30 degrees. However, the angle need not be particularly large and an angle of about 10 degrees has been found to be satisfactory in producing a shear layer. When the rows of apertures 76 are aligned at an angle, portions of the extrudate masses of food material being forced out of the apertures 76 are contacted at the top and bottom of the mold opening 32 by the overlying upper plate 50 and by the underlying plate 26, respectively. Movement of the mold plate 30 effects a frictional engagement of these extrudate masses. This forces and deforms some of the food material from each discrete mass in a direction generally parallel to the direction of movement of the mold plate 30. This tends to cause the deformed food material to be carried across the patty surface to thereby effect a further linking of the extrudate masses of material. Although the above-described shear layer functions to trap additional air and vapors in the interstitial voids of the patty and functions to provide further patty strength (which reduces the tendancy of the patty to break apart) , the shear layer L has a characteristic which is undesirable in some situations. Specifically, in a patty made from ground meat containing tissue fibers, the shear layer tends to shrink non-uniformly when the patty is cooked. When a patty of food material containing tissue fibers is molded with a shear layer according to the above-described method, the tissue fibers, which are generally randomly distributed in ground meat material, tend to become unravelled and tend to become aligned in the surface of the shear layer. This is due to the frictional forces acting on the shear layer as the mold plate 30 moves relative to the adjacent fixed plates in the molding machine. Thus, if a substantially round patty were produced with such a shear layer, the tissues would be aligned in the surface of the shear layer of that patty in a generally parallel configuration. When the patty is cooked, the tissue fibers contract in the cooking process and cause a shrinkage of the round patty in a direction of tissue fiber alignment. The patty thus becomes somewhat oval after cooking. To avoid this problem, a patty formed with a shear layer L may be initially formed with a slightly elongated shape in the manner described above with reference to Figures 23-27 for the patty 35a. Since the patty 35a is moved by the mold plate 30 in a direction parallel to the stored-up forces in the patty, the patty will elongate (Figure 24) in the same direction as the tissue fiber alignment when the patty is ejected from the mold opening 32. Then, when the patty is cooked, the tissue fibers will contract and produce a patty that has an essentially round or circular shape (Figure 25) . This feature is of aesthetic importance, especially in restaurants where the consuming public seems to prefer a generally circular cooked patty over a non-circular patty, at least with hamburger-type food products. SECOND EMBODIMENT The first embodiment of the subassembly 60 illustrated in Figures 2-7 may be modified to form a second embodiment for use in a conventional molding machine. The components of the second embodiment illustrated in Figures 8-10 are identical to the components of the first embodiment of the subassembly 60 except for the second embodiment foraminous member which is designated by the reference numeral 62' and except for the associated second embodiment agitator bars which are designed by the reference numerals 90A « and 90B' . The foraminous member 62' has a generally flat, planar upstream surface 72' with an array of openings defined in the upstream side of the foraminous member 62 by the apertures 76* . The openings of the aperture 76* at the upstream side 72* are arranged in a first set of spaced-apart parallel rows and in a second set of spaced-apart parallel rows in the same manner as the apertures 76 in the first embodiment of the foraminous member 62 described in detail above with reference to Figures 2-7. The foraminous member 62' is also provided with a pair of guide slots 94A' and 94B* . One of the guide slots is parallel to the first set of parallel rows of foraminous member aperture openings and the other of the guide slots is parallel to the second set of parallel rows of foraminous member aperture openings. A projecting member 95A* of the agitator bar 90A' is received in the guide slot 94A' and a projecting member 95B' of the agitator bar 9OB' is received in the guide slot 94B'. Unlike in the first embodiment of the foraminous member 62 described above with reference to Figures 2-7, the second embodiment of the foraminous member 62' is not flat and smooth between the rows of apertures 76'. Rather, as best illustrated in Figures 9 and 10, the foraminous member 62' defines a plurality of spaced-apart, parallel channels 201' and a plurality of spaced-apart, parallel channels 203' which are oriented at an angle to the channels 201* . Each channel 201* is located parallel to and between a pair of adjacent rows of the aperture openings of the first set of rows and receives a tooth 92A' of the agitator bar 90A* . Similarily, each channel 203' is located parallel to and between a pair of adjacent rows of the aperture openings of the second set of rows and receives a tooth 92B* of the agitator bar 90B'. Although the agitator bar 90A 1 is shown in Figure 10 as not being in contact with the foraminous member 62* , it is to be realized that contact may be established between the tops of the agitator bar teeth 92A' and the bottom of the channels 201' and/or between the upstream surface 72' of the foraminous member and the portions of the bar 90A* between the teeth 92A' . Indeed, it has been determined that a biasing of the agitator bar 90A* , as well as bar 90B', against the foraminous member 62' is preferred when molding some types of food material, such as raw ground beef, since a more efficient tissue fiber dislodging action can be effected. Means for biasing an agitating bar against a foraminous member are described in detail hereinafter with reference to the modified embodiments illustrated in Figures 11 and 14. The foraminous member 62' is adapted to be assembled with the agitator bars 90A' and 90B' , and with the other components of the subassembly (plates 64, rods 98, tray 96, and plate 66 which are in Figures 2 and 3) . The entire subassembly can be mounted in a molding machine, such as molding machine 20, in the same manner as a first embodiment of the subassembly 60 described above with reference to Figures 6 and 7. The mechanical operation of the components of the subassembly with the second embodiment of the foraminous member 62* and bars 90A' and 90B' is substantially identical and functionally analogous to the operation of the components of the first embodiment of the subassembly 60 described above with reference to Figures 2-7. THIRD EMBODIMENT A third embodiment of the subassembly is similar to the first embodiment of the subassembly 60 of Figure 2 and is illustrated in Figures 11 and 12. The components of the third embodiment of the subassembly are identical to the components of the first embodiment of the subassembly 60 illustrated in Figures 2-7 except for the agitator bars which, in the third embodiment illustrated in Figures 11 and 12, are designated by reference numerals 90A* • and 90B'*. The reference numerals for the other subassembly components shown in Figure 12 remain the same as in Figures 2-7 for the first embodiment. Each agitator bar 90A' * and 90B* ' has spaced-apart, angled teeth 92A' ' and 90B* ' , respectively, and projecting members 95A' ' and 95B' ' , respectively. In these respects, the agitator bars 90a* • and 90B" are identical to the agitator bars 90A and 90B, respectively, of the first embodiment of the subassembly 60 described above with reference to Figures 2-7. However, each agitator bar 90A* ' and 90B* ' also includes a unique biasing structure. Specifically, each agitator bar 90A' and 90B' is spring-biased from the bottom of the channel in its receiving tray in the frame 96 (Figure 12) so as to force the agitator bar upwardly against the upstream side 72 of the foraminous member 62. Figure 12 (which shows the molding apparatus with the modified agitator bars in place) is a fragmentary, cross-sectional view that results after replacing the agitators bar 90A and 90B in Figure 6 with the corresponding agitator bars 90A' ' and 90B' * and then taking a transverse cross-section of the apparatus (90 degrees to the plane of Figure 6 drawing) . With reference to agitator bar 90A' ' , the bar is seen tq have a base 300A* * for being received in the associated tray 97A of the frame 96 (Figure 12) . The base 300A' ' defines a base projection 301A' ' at each end of the bar for supporting .the bar in the frame tray 97A while accommodating deflection of a portion of the bar intermediate of the base projections 301A* * . The agitator bar 90A' ' defines an endwise slot 303A' ' at each end of the bar. Each slot 303A' * extends only part way along the length of the bar and terminates short of the middle of the bar. When the bar 90A* ' is mounted in the tray 97A and when the tray frame 96 is properly positioned within the subassembly as illustrated in Figure 12, then the agitator bar teeth 92A' ' are urged against the foraminous member upstream side 72 under a force (e.g., 40-80 pounds) sufficient to decrease the width of the endwise slots at 303A' ' and sufficient, to slightly deflect the portion of the agitator bar intemediate of the base projection 301A' ' . In this manner, the ends of the agitator teeth 92A* ' are forced in tight engagement with the foraminous member upstream side 72. This provides for an even more [SE OMPI effective dislodgement of the tissue fibers from the upstream side of the foraminous member 62 compared to those designs in which there is a small clearance between the agitator bar and the foraminous member upstream side 72 and even compared to those designs in which the agitator bar teeth are permitted to contact the foraminous member but are not biased against the foraminous member with a significant degree of force. The design and operation of the other agitator bar 90B' * are identical to the design and operation of the agitator bar 90A' ' described above. The elements of the agitator bar 90B'' that are identical to the elements of the agitator bar 90A' ' are designated with the same reference numerals as used in the illustration of the agitator bar 90A* ' but the agitator bar 90B* ' reference numerals are followed by the designation B 1 ' rather than A' ' . FOURTH EMBODIMENT Another modification of the agitator bar construction is illustrated in Figures 13 and 14 which show two modified agitator bars, bar 90A' * ' and bar 90B''*. These bars 90A' ' and 90B' ' can be substituted for the bars 90A and 90B in the first embodiment of the subassembly 60 illustrated in Figures 2-7 to yield a fourth embodiment of the subassembly. Each agitator bar has a plurality of spaced-apart teeth — teeth 92A' ' * for agitator bar 90A » " and teeth 92B' * * for agitator bar 90B". Agitator bar 90A' * ' has a projecting guide member 95A' ' ' for being received in the foraminous member slot 94A (Figure 14) and the agitator bar 90B' ' * has a guide member 95B* ' ' for being received in the guide slot 94B. Note that Figure 14 is a cross-sectional OMPI view similar to Figure 12 but with the agitator bar 90A* * of Figure 12 replaced with the agitator bar 90A' ' ' of Figure 13. A unique structure is provided for biasing the agitator bars upwardly against the upstream side 72 of the foraminous member 62. Specifically, a leaf-spring 310A' * ' is provided on the bottom of the agitator bar 90A' • ' and a similarly spring 31OB* ' ' is provided on the bottom of the agitator bar 90B , , , . When each bar is disposed within the tray channel (channel 97A as illustrated in Figure 14 for bar 90A' •'), the leaf spring is compressed and stressed between the bottom of the associated agitator bar and the tray. This causes the agitator bar teeth to be urged upwardly against the upstream side 72 of the foraminous member 62 to provide an improved tissue dislodging action. It has been determined that the use of agitator bars biased against the upstream side of the foraminous member is particularly effective for molding patties of raw ground beef when the biasing force is on the order of 40-80 pounds. FIFTH EMBODIMENT Figure 15 illustrates another modified form of the foraminous member 62' ' . The member 62' ' is similar to the member 62 of the first embodiment of the subassembly 60 described above with reference to Figures 2-7. However, the member 62' ' has differently shaped guide slots 94A' * and 94B' ' and can be employed with the other components of the first embodiment of the subassembly 60 to form a fifth embodiment of the subassembly. Each guide slot 94A' * and 94B" has two angled portions or legs for guiding the associated agitator bar (not illustrated, but which may be identical or similar to the bars 90A and 90B described above with reference to Figures 2-7) . One leg of each slot is parallel to one set of the rows of openings defined by the apertures 76* * and the other leg of each slot is parallel to the other set of rows of openings defined by the apertures 76* * . Thus, each agitator bar will move parallel to one set of rows for the first part of its traverse along the member 62' ' and will then move parallel to the other set of rows for the second part of its traverse along the member 62' * . If the guide member of each agitator bar has an elongate shape (like the member 95A of the bar 90A illustrated in Figure 4) , then one leg of each associated guide slot 94A' ' or 94B' * should be wider than the other leg as illustrated to accommodate the change in direction of the bar movement. If the guide member is instead provided in the form of a cylindrical pin, then both legs of each guide slot may be the same width. With the two-legged guide slot design, the agitator bar teeth, if they are elongate and angled as are the teeth of the bars 90A and 90B illustrated in Figures 3-4, may pass over a portion of some of the apertures 76' * during the second part of the bar traverse along the member 62* ' . However, if this is not desired, the length of each tooth could be reduced as necessary. OTHER MODIFICATIONS —The Foraminous Member While it is presently preferred to incorporate the foraminous member with non-vertical apertures in a patty molding machine of the type illustrated herein and which has means for preventing tissue fiber build-up, the foraminous member structure is not limited to use with any particular form of patty molding machine, and may be incorporated into a machine with or without a means for preventing tissue fiber build-up. For example, a foraminous member having inclined (or other non-vertical apertures) may be incorporated in a machine having no means for preventing tissue fiber build-up, or incorporated in machines of the types disclosed in U.S. Patent Nos. 4,272,864; 4,338,702; and 4,343,068. Furthermore, the apertures 76 need not be circular in cross-section, and can have other shapes such as a square, a rectangle, an oval, a corkscrew, or a star shape to name but a few. The disclosed embodiments of the foraminous member are not limited to a configuration where the food material is forced upwardly through the apertures. Instead, the embodiments may be incorporated in configurations where meat, or other food material, is forced horizontally or downwardly through the apertures and into a mold cavity. —The Agitator Bar Structure Although the third and fourth embodiments illustrated in Figures 11-14 employ two biased agitator bars, it is to be realized that only one biased agitator bar may be sufficiently effective in some applications. On the other hand, more than two biased agitator bars may be used if desired. Further, although the embodiments of the agitator bars are illustrated in Figures 2-14 as having teeth, the disclosed molding apparatus is not to be limited to bars with tooth structures. Figure 16 illustrates, in a somewhat schematic fashion, the general concept of moving an agitator bar 290 (with or without teeth) against the upstream side 272 of a foraminous member 262 which defines a plurality of apertures to 276. A patty mold 230 is provided for being moved into position adjacent the downstream side of the foraminous member -262. The mold 230 defines a mold opening 232 which may have a closed bottom so as to define a cavity. Alternatively, the mold opening may extend completely through the mold plate 230 and be blocked as necessary by another plate (not shown) . The mold plate 230 may be moved by any suitable means into a position adjacent the foraminous member 262 for receiving food material extruded through the foraminous member 262. The mold plate 230 may reciprocate, may rotate, or may otherwise be moved as necessary in one or more directions to receive the food material and then to permit the food material to be ejected or removed from the mold opening 232. On the other hand, the patty mold plate 230 may remain stationary while the agitator bar 290 and foraminous member 262 are moved together into proper position adjacent the mold plate 230. Alternatively, proper positioning may be effected by moving both the mold plate 230 and the combination of the agitator bar 290 and foraminous member 262. In any case, in a preferred form of agitating the food material adjacent the upstream side 272 of the foraminous member 262, the bar 290 is slidably engaged with the foraminous member upstream surface 272 in surface-to-surface contact. This may be effected by constructing the components (not illustrated) for supporting the foraminous member 262 and agitator bar 290 to provide substantially no clearance between the contacting surfaces of the bar 290 and foraminous member 262. However, it has been determined that sliding contact between the bar 290 and foraminous member 262 can be advantageously effected by biasing either one of, or both, the agitator bar 290 and foraminous member 262 into engagement. In Figure 16, a force for biasing the agitator bar 290 against the foraminous member 262 is represented by an arrow 292. With the bar 290 thus biased against the foraminous member 262, relative movement is effected between the bar 290 and the foraminous member 262 in the direction indicated by the arrow 294. The bar 290 may be moved relative to the foraminous member 262, the foraminous member 262 may be moved relative to the bar 290, or both the bar 290 and the foraminous member 262 may be moved. The direction of relative movement between the bar 290 and the foraminous member 262 need not be one of colinear reciprocation as schematically illustrated in Figure 16. Rather, as illustrated in Figure 21, the bar 290 may be moved along four paths indicated by arrows 296. At each corner of the square-path movement, the bar 290 would be rotated to face in the direction of the next straight line path of movement. The bar 290 would be long enough to insure that one complete cycle of bar movement agitated the food material adjacent all of the apertures 276 in the foraminous member 262. Figure 22 schematically illustrates another manner in which the agitator bar 290 may be moved relative to the foraminous member 262. Specifically, the bar 290 may be pivotally mounted at point 297 for rotation relative to the foraminous member 262. The bar 290 could then be rotated as indicated by arrows 298 to sweep across all of the apertures 276. In both of the embodiments illustrated in Figures 21 and 22, it is to be realized that the agitator bar 290 may remain stationary and that the <JΓΛ-_ ^^Emo:* foraminous member 262 may be moved as necessary to effect the relative travel path indicated by the arrows 296 or 298.. Alternatively, both the foraminous member 262 and the bar 290 may be rotated relative to each other, either together, or in an intermittent alternating sequence. Regardless of the nature of the relative motion between the agitator bar or bars and the foraminous member, such motion may be effected before, during, or after the step of forcing the food material through the foraminous member and into the mold cavity. The paths of relative movement illustrated in Figures 16, 21, and 22 are merely illustrative of some specific paths. Of course, many other paths of movement will be readily apparent. Further, if desired, more than one agitating bar may be employed to move in the same or different paths. Figure 17 illustrates a specific means for biasing an agitator bar 390 into engagement with the upstream surface 372 of a foraminous member 362. The bar 390 is adapted to be reciprocated along the foraminous member 362 over apertures 376 defined in the member 362. The bar 390 is retained on either end by a bracket 392 secured with screws or bolts 393 to the foraminous member 362. As best illustrated in Figure 18, each end of the agitator bar 390 defines a generally cylindrical cavity or bore 394 for receiving a generally cylindrical resilient member 395. The resilient member 395 is forced downwardly and is somewhat compressed by the overlying bracket 392 which is secured to the foraminous member 362. In this manner, the agitator bar 390 is biased on each end against the upstream surface 372 of the foraminous member 362. Figures 19 and 20 illustrate still another means for biasing an agitator bar 490 against the upstream surface 472 of a foraminous member 462 which defines apertures 476. In Figure 20 a portion of a patty mold plate 430 is shown in position below the foraminous member 462 to locate the mold opening 432 in substantial alignment with the apertures 476. The bar 490 is in the form of an arcuate, spring steel blade slidably received within an inverted U-shaped holder 492. The foraminous member 462 is provided with overlying flanges 493 for engaging the top of the holder 492 when it is moved into position (along the path of arrow 495 in Figure 19) on the foraminous member 462 as illustrated in Figure 20. To effect this engagement, the bottom of the bar 490 must, of course, be initially pushed upwardly some amount so as to decrease the curvature of the bar. The bar 490 will thus be under constant stress, and the bottom of the bar 490 will be effectively biased into engagement with at least the central portion of the foraminous member 462 which defines the apertures 476. In the embodiments illustrated in Figures 11-14 and 16-20, a variety of mechanisms are disclosed for biasing an agitator bar into contact with the upstream surface of the foraminous member. It is to be realized that other biasing mechanisms may be employed. For example, in addition to various types of springs, sprung assemblies, and resilient mechanisms, it is also possible to use pneumatic devices or other biasing devices. If no direct relative biasing between the agitator bar and foraminous member is provided, any clearance between the agitator bar and the upstream surface of the foraminous member should be OMPI { &>*, WIPO A sufficiently small to effect an agitation of the food material in a manner sufficient to dislodge tissue fibers that may have lodged on the upstream side of the foraminous member. The novel method, structure, and apparatus described herein for facilitating flow of tissue fibers through a foraminous member in a molding machine can be used in conjunction with other methods and apparatus for forming patties of food material. For example, if desired, the various disclosed embodiments of the agitator bars may be used with the methods and apparatus disclosed in the above-discussed U. S. Patent Nos. 4,272,864, 4,338,702, including with the disclosed method and apparatus for moving the food material first in one direction and then in a second, opposite direction through the foraminous member. Also, the agitator bars described herein may be used with the methods and apparatus disclosed in the above-discussed U. S. Patent Nos. 4,343,068 and 4,356,595. Further, the embodiments of the agitator bars described herein may be used, with appropriate modifications, in conjunction with a variety of foraminous member designs including, among others, 1) a foraminous member with vertical, non-inclined apertures, 2) a foraminous member with non-vertical apertures, 3) a foraminous member with slots connecting the apertures, and 4) a foraminous member with ribs on the upstream side. From the foregoing, it will be understood that numerous variations and modifications may be effected without departing from the true spirit and scope of the novel concept of the invention. It is to be understood that no limitation with respect to OMPI the specific method, apparatus, and product illustrated herein is intended or should be inferred. It is, of course, intended to cover by the appended claims all such modifications as fall within the scope of the claims.

Claims: WHAT IS CLAIMED IS: 1. A method for forming a patty of food material comprising the steps of: (a) providing a foraminous member having 1) an upstream side, 2) a downstream side, 3) and ' a plurality of apertures between said upstream side and said downstream side and communicating therebetween; (b) providing mold parts defining a mold opening and at least a portion of a mold cavity having the shape of at least a portion of the exterior surface of said patty and positioning said mold parts to dispose said mold opening adjacent said downstream side of said foraminous member; and (c) forcing said food material under pressure from the upstream side of said foraminous member through said foraminous member apertures and into said mold opening as extrudate masses which together form said patty; said method characterized in that step (a) includes providing at least some of said apertures each having at least the portion of the aperture that is adjacent the mold opening oriented so as to discharge the food material into the mold opening in a direction that is not perpendicular to the plane of the mold opening; and step (c) includes forcing some of said food material through said apertures into said mold opening in one or more directions that are not perpendicular to the plane of the mold opening to form said patty. 2. The method as set forth in claim 1 further characterized in that OMPI said mold opening includes an upright peripheral wall; said apertures are cylindrical and are inclined in the same direction toward one side of said peripheral wall; and said step of forcing said food material under pressure is performed by moving said extrudate masses toward said one side of said peripheral wall and compressing said extrudate masses between said one side of said peripheral wall and a side of said peripheral wall opposite said one side, whereby, upon ejection of said patty from said mold opening, said patty expands in the direction in which said extrudate masses have been compressed. 3. The method as set forth in claim 2 further characterized in that a plate forms one side of the mold cavity opposite the downstream side of said foraminous member; and said step of forcing said food material under pressure is performed by deflecting said extrudate masses off of said plate and directing said deflected extrudate masses toward said one side of said peripheral wall. 4. The method as set forth in claim 1 further characterized in that said method includes a further step (d) before, during, or after step (c) , of agitating said food material adjacent said foraminous member upstream side to dislodge tissue fibers. 5. An apparatus for molding a patty of food material comprising: (a) a foraminous member having an upstream side and a downstream side, said foraminous member defining a plurality of apertures extending through said foraminous member; (b) mold parts defining a mold opening and at least a portion of a mold cavity that has the shape of at least a portion of the exterior surface of said patty and that is positionable adjacent said downstream side of said foraminous member; and (c) means for forcing said food material under pressure from the upstream side of said foraminous member through said foraminous member apertures and into said mold opening as extrudate masses which together form said patty; said apparatus characterized in that at least some of said apertures each have at least the portion of the aperture that is adjacent the mold opening oriented so as to discharge the food material into the mold opening in a direction that is not perpendicular to the plane of the mold opening. 6. Apparatus as set forth in claim 5 further characterized in that said apertures are parallel with one another and inclined at a common angle. 7. Apparatus as set forth in claim 5 further characterized in that said apertures are slanted cylindrical bores arranged in rows with each bore having a diameter of about 3mm. 8. Apparatus as set forth in claim 5 further characterized in that said apertures are all inclined at a common angle of between about 26°and about 45°. 9. Apparatus as set forth in claim 5 further characterized in that an agitator bar is provided for being moved adjacent said foraminous member upstream side to dislodge tissu fibers. 10. A patty of food material formed by the steps of: (a) providing a foraminous member having 1) an upstream side, 2) a downstream side, 3) and a plurality of apertures between said upstream side and said downstream side and communicating therebetween; (b) providing mold parts defining a mold opening and at least a portion of a mold cavity having the shape of at least a portion of the exterior surface of said patty and positioning said mold parts to dispose said mold opening adjacent said downstream side of said foraminous member; and (c) forcing said food material under pressure from the upstream side of said foraminous member through said foraminous member apertures and into said mold opening as extrudate masses which together form said patty; said patty characterized in that step (a) includes providing at least some of said apertures each having at least the portion of the aperture that is adjacent the mold opening oriented so as to discharge the food material into the mold opening in a direction that is not perpendicular to the plane of the mold opening; and step (c) . includes forcing said food material through said oriented apertures into said mold opening in one or more directions that are not perpendicular to the plane of the mold opening to form said patty with at least some of said extrudate masses being interwoven. 11. The patty of food material in accordance with claim 10 further characterized in that said patty has generally parallel 'top and bottom surfaces and a peripheral edge extending between said top and bottom surfaces, the side-to-side dimension of said patty being greater in a first direction than in a second direction perpendicular to said first direction, at least some of said extrudate masses each having at least a portion disposed at an acute angle relative to the top and bottom surfaces of said patty and also disposed in shingled relationship with respect to portions of some adjacent extrudate masses, said angled and shingled portions of said extrudate masses being generally aligned in said first direction. 12. A patty of food material comprising: a plurality of extrudate masses united, together in a packed array, said patty having generally parallel top and bottom surfaces and a peripheral edge extending between said top and bottom surfaces, the side-to-side dimension of said patty being greater in a first direction than in a second direction perpendicular to said first direction, at least some of said extrudate masses each having at least a portion disposed at an acute angle relative to the top and bottom surfaces of said patty and also disposed in shingled relationship with respect to portions of some adjacent extrudate masses, said angled and shingled portions of said extrudate masses being generally aligned in said first directiqn. 13. An improvement for an apparatus for molding a patty of food material, said apparatus including at least 1) a food material reservoir, 2) a mold plate defining a mold opening adapted to be moved between a patty molding position and a patty ejecting position spaced away from said patty molding position, said mold opening defining at least a portion of a mold cavity into which the food material is forced from said food reservoir to form a molded patty when said mold opening is in said patty molding position, 3) means for moving said mold plate between said patty molding position and said patty ejecting position, and 4) means for forcing some of said food material into said mold opening to form said patty, said improvement characterized in that a subassembly is provided for the apparatus and includes a foraminous member having an upstream side and a downstream side, said foraminous member having a plurality of apertures extending from said upstream side to said downstream side, said foraminous member adapted for being disposed between said food material reservoir and said mold plate at a location for being in registry with said mold opening when said mold plate is in said patty molding position so that said foraminous member downstream side is then located adjacent said mold opening, at least some of said apertures each having at least the portion of the aperture that is adjacent the mold opening oriented so as to discharge the food material into the mold opening in a direction that is not perpendicular to the plane of the mold opening.

Inventors: HOLLY JAMES A, HOLLY, JAMES, A.
Applicants: HOLLY SYSTEMS INC, HOLLY SYSTEMS, INC.
Application year: 1984
Main classification: A22B5
IPC codes: A22C7, A23L1, A23P1