Abstract:
A device and method for forming pieces of cheese weighing several ounces or less while retaining the skin normally formed on the cheese piece in the cooling process, and at the same time obtaining a desired internal structure. Warm plastic cheese is extruded into a first mold having a sliding low friction end cap, by means of a screw extruder, at 1000 pounds per square inch; the first mold is then positioned over a second mold having a plurality of forming chambers formed therethrough, the second mold is made of UHMW and the volume of the second mold is slightly less than the volume of the first mold. Pressure at 3000 pounds per square inch is applied to the mold end cap while the cheese in the first mold is still plastic, forcing the cheese into the forming chambers; the cheese pieces formed are retained in the forming chamber until a skin is formed and then they are ejected into a brining tank.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The Invention is a cheese extruding machine for forming pieces of cheese weighing several ounces or less. 
     2. Related Art 
     Petitioner&#39;s invention is used to make small pieces of cheese of uniform density and of exact weights and dimensions at high speed, while retaining the skin which is formed on the cheese piece as it is cooled. 
     The device was designed for forming small pieces of Italian type cheeses such as mozzarella, provolone or scamorza. 
     In prior art devices, warm plastic cheese is extruded into a stainless mold. A 40 pound block is commonly formed. The mold is chilled, forming a skin on the cheese block which helps hold the shape of the block when the block is ejected from the mold. Such a device is shown in U.S. Pat. No. 4,613,294. The block formed is then put into a brining tank or trough. 
     After the block has been brined, it can be cut into smaller rectangular pieces by a harp. Such a harp can be seen in U.S. Pat. No. 4,646,602. 
     Pieces of cheese that have been cut by a harp cannot be bent without cracking. Cutting the block removes the skin formed on the block while cooling. 
     The skin formed on cheese, during the forming process, has useful properties. A piece of cheese retaining the skin formed can be bent without cracking. It is an object of this invention to make small pieces of cheese retaining the skin formed in cooling. 
     The density of the cheese in 40 pound blocks and in blocks formed directly out of the screw extruder varies. As the screws slip, cheese consistency varies in the cheese column formed in the extruder. 
     Brining time required is a function of the size of the cheese block to be brined. A small piece of cheese may be brined in several minutes, while a 40 pound block may require 24 hours of brining. Brining the cheese, chills, salts, hardens and flavors the cheese. It is an object of this invention to make small pieces of cheese and to brine after formation, to lessen brining time. 
     Small pieces of cheese may be formed by using an extrusion process, as shown in U.S. Pat. No. 4,339,469. In such a process, a screw extruder is used to force a column or rope of cheese out of an extrusion hole, into a brining tank. The ropes, after brining, are then cut to desired sizes. 
     While the extrusion system retains the useful skin on all but the cut ends, shapes that can be extruded are limited. As the cheese is extruded out of the high pressure extruder into the atmospheric pressure brining tank, the cheese expands unpredictably and takes on irregular shapes. Density of the extruded cheese rope formed by the extruder varies with slippage of the screw extruder. The cheese then must be cut. It is difficult to cut the cheese ropes formed to exact weight. 
     Petitioner&#39;s device forms a surface skin and an internal structure in the cheese piece formed, by working the cheese, that allows the piece to be bent and handled in further processing. 
     Both the harp and the extruder can be used to produce small individual serving pieces of varying sizes. Because the pieces formed by the harp or extruder vary in size and in density, they must be sold by weight. Size variation also complicates feeding of the individual pieces to other machines. 
     The invention extrudes warm plastic cheese by means of a screw extruder into a first mold, then while the cheese in the first mold is still plastic, positions the first mold over a second mold and under great pressure, extrudes the cheese in the first mold into the second mold. 
     The invention is a cheese extruder specifically designed for the production of cheese pieces weighing several ounces or fractions of an ounce. 
     The extruder comprises a movable mold plate having two adjustable molds mounted on it. The bottom of the molds are open to the entrance of cheese, forced into the mold by a screw extruder, the outlet of which is under and bears on the movable mold plate. 
     The top of the mold is closed off by a vertically movable mold cap plate. 
     As the plate moves back and forth over the cheese inlet, the inlet is open to one mold or to the other, or is blocked by the plate. A reciprocating device is shown in the specifications. A rotary mold plate system has been designed. 
     As one mold is positioned over the cheese inlet, the second mold is positioned over an extrusion mold which has a number of cheese extrusion holes formed in it. The extrusion mold reciprocates in a direction normal to the direction of movement of the mold plate. 
     The block of cheese formed in the mold carried by the mold plate, is forced out of that mold under pressure into the extrusion mold in which the desired shape and size of the finished piece has been formed. This works the cheese and compresses it. 
     The extrusion mold is then moved under an ejector plate mounted over a brine trough, and the formed pieces are ejected for brining. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a disassembly view of one embodiment of the invention showing the frame and housing within which the mold plate reciprocates. 
     FIG. 2 is a disassembly view of the device with the housing removed to show operation of the device. 
     FIG. 3 is a disassembly view with housings removed to show filling of the extrusion mold. 
     FIG. 4 is a view showing ejection of cheese pieces from the extrusion mold. 
     FIG. 5 is a section view taken through the device on a horizontal plane to show operation of hydraulic cylinders. 
     FIG. 6 is an end view of the device, in partial section taken from the right side. 
     FIG. 7 is an end view with a section taken through the extrusion mold. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The device comprises the following elements: 
     
         ______________________________________Frame 20Cheese extruder pipe               22Outlet              24Outlet flange       26UHMW pad            28Housing             30Housing             32Control Box         34Housing Frame       36Housing Frame       38Legs                40Legs                42Ejector mount       44Ejector mount       46Brining trough      48Support rail        50Support rail        52Support rail bottom surface               54Support rail bottom surface               56Support rail height adjusting               57deviceMold plate          58Mold                60Mold                62Flange              64Mold plate retainer 66Mold cap            68Mold cap rub rails  70Secondary molding station               72Second molding station               74Extrusion mold      76Extrusion mold      78Support leg         80Support leg         82Support leg         84Support leg         86Forming chambers    88Venting plate       90Discharge plate     92Scraper             93Cheese              94Hydraulic cylinder  96Spring biased support               98Spring biased support               100Weeper holes        102Hydraulic cylinder  104Ejector plate       106Ejector fingers     108Ejector plate aligner               109Hydraulic cylinder  110Attachment          112Hydraulic cylinder  114Hydraulic cylinder  116______________________________________ 
    
     Petitioner&#39;s device is used to make small pieces of cheese, to close tolerances in weight and dimensions, and an unbroken surface skin. 
     FIG. 1 shows frame 20, of the device. Frame 20 straddles plastic cheese extruder pipe 22. Warm plastic cheese is forced through a screw extruder, not shown, and flows out of outlet 24. 
     Outlet 24 is surrounded by flange 26. A low friction UHMW plastic pad 28 is mounted on top of flange 26. 
     At either side of pipe 22 are located housings 30 and 32. The hydraulic cylinders used to force the plastic cheese into the extrusion mold are mounted in these housings. Shown in dotted line at 34 is location of control box 34. 
     Housings 30 and 32 are connected to housing frames 36 and 38 by legs 40 and 42. 
     On the face of housing 30 and housing 32 are mounted ejector mounts 44 and 46. 
     In dotted line in FIG. 1 at 48 is shown the location of a brining trough; the extruded pieces of cheese are ejected into the brining trough. 
     Above UHMW pad 28 can be seen support rails 50 and 52. 
     The mold plate reciprocates above outlet 24, into housings 30 and 32. The mold plate slides across UHMW gasket or pad 28. The mold cap rub rails 70 bear on the bottom surface of support rails 50 and 52 when the mold is full. 
     FIG. 2 is a view of the with housings 30 and 32 removed, to show operation. 
     Mold plate 58 has two molds 60 and 62 mounted thereon. Molds 60 and 62 are mounted within the perimeter of plate 60, leaving an outside flange 64, between molds 60 and 62. Mold plate retainer 66 is a rectangular L-shaped piece of steel which retains mold plate 58 as it reciprocates back and forth within the area defined by the mold plate retainer. 
     Molds 60 and 62 are open on the bottom, as can best be seen in FIG. 2. As cheese flows out of outlet 24, the cheese fills the mold. Mold cap 68 moves upward as cheese is extruded into the mold, filling the area of the mold. Mold cap 68 is a two inch thick piece of UHMW. 
     Mold cap rub rails 70 are UHMW plastic runners affixed to the top of the mold cap 68. As cheese is extruded into the mold 62, the cap rises until the runners contact support rail bottom surfaces 52 and 54. 
     The height of mold cap rub rails 70 can be varied to vary the amount of cheese forced into the mold. Support rails 50 and 52 can also be adjusted up or down by screw adjusters 57 to adjust the amount of cheese entering the mold. 
     Mold plate 58 is reciprocated back and forth over outlet 24 by a hydraulic cylinder not shown in FIG. 2. 
     Mold 60 can be stopped in two positions. In one position it is stopped over a secondary molding station 72. Mold 62 is stopped over outlet 24 or over secondary molding station 74 as can best be seen in FIG. 2. 
     At stations 72 and 74 are mounted extrusion molds 76 and 78. 
     Mold 78 is slidably mounted, as is mold 76. Mold 76 is reciprocated from its position beneath mold 60, on support legs 80 and 82. Mold 78 is reciprocated from its position beneath mold 62 on support legs 84 and 86. A hydraulic cylinder, not shown in this figure, is used to move extrusion mold 78 from beneath mold 62 after extrusion, to a second position, above a brining trough, for discharge of formed pieces. 
     Extrusion mold 78 shown in FIG. 2, is used to form 84 pieces of cheese of rectangular shape. The top of the forming chambers 88 can be seen in this figure. 
     The shapes formed can be star shaped, round or any two dimensional shape desired with length being fixed by the depth of the chamber. 
     At the bottom of extrusion mold 78 can be seen venting plate 90 and discharge plate 92. 
     FIG. 3 shows the device with the housings removed and at the point where hydraulic pressure is being used to fill extrusion mold 78. 
     A section is removed to show operation. Cheese 94, retained in mold 62, by mold plate 58, bearing on the bottom surface of support rails 56 and 54, is subject to pressure exerted by hydraulic cylinder 96, smaller spring biased supports 98 and 100 follow hydraulic cylinder 96 down and provide added support to mold cap 68 as force is applied. 
     The still plastic cheese contained within the mold 62 is forced into extrusion mold 78 with its forming chambers 88. Chambers 88 are open at the bottom and are located over weeper holes 102. As the hydraulic cylinder 96 presses down on mold cap 68, the plastic cheese is forced into forming chambers 88; as the cheese is formed into chambers 88, air is forced out of the chambers through weeper holes 102. At the end of the extrusion cycle a small amount of cheese is also forced out of weeper holes 102. The size of the small weeper holes and the volume of cheese in the first mold keeps all but a small amount of cheese from being forced out of the weeper holes. A small tail or flashing of cheese is formed at the weeper holes. The tail is shorn off as mold 78 is forced outward on legs 84 and 86 over a brining tank. 
     The cheese shapes formed by the double extrusion process have useful properties which aid in further processing. The pieces are of uniform density and have an unbroken surface skin. 
     At the left side of FIG. 3 can be seen mold 76 in position to have the formed shapes ejected. 
     Ejection of formed cheese pieces can best be seen in FIG. 4. Hydraulic cylinder 104 is attached to 32, at mount 46. Cylinder 104 moves ejector plate 106 down; plate 106 has affixed to its bottom surface ejector fingers 108. 
     As cylinder 104 is energized to eject pieces from the extrusion mold 78, plate 106 moves down, forcing fingers 108 into the forming chambers 88, forcing the formed cheese pieces out of the mold and into a brining trough. 
     FIG. 5 is a section view, showing a section taken through the extruder on a horizontal plane. FIG. 5 best shows operation of the hydraulic cylinders to move the various molds in a horizontal plane. 
     Hydraulic cylinder 110 is affixed to mold plate 58 at 112. This cylinder 110 moves mold plate 58 back and forth across outlet 24. 
     Hydraulic cylinder 114 moves extrusion mold 76 back and forth on legs 80 and 82, from a position where mold 76 is under mold 60 to a second position under the discharge plate, to eject the formed pieces. 
     Hydraulic cylinder 116 moves extrusion mold 78 back and forth on legs 84 and 86, from a position under mold 62 to a second position under discharge plate 90. 
     FIG. 6 is an end view of the device with Section taken through mold 62 and extrusion mold 78. The view is taken from the right side. In FIG. 6, mold 62 containing warm plastic cheese 94 is positioned above extrusion mold 78. 
     As plunger 96 is actuated, plunger 96 forces cold cap 68 down, forcing the plastic cheese into forming chambers 88; pressure is applied until the entrapped air in chambers 88 is forced out, the mold filled, and a small amount of cheese forced out of weeper holes 102. 
     Hydraulic cylinder 96 is then withdrawn. Hydraulic cylinder 116 is engaged moving extrusion mold 78 outward on tracks 84 and 86. As the mold moves outward, the cheese tail or flashing extending into weeper holes 102 is sheered off, either falling out through the larger holes in discharge plate 92 or remaining to be forced out in the next compression cycle. 
     Scraper 93 extends across the surface of mold 78. As the mold is moved outward, scraper 92 scrapes off any cheese standing above chambers 88. 
     FIG. 7 is a side view with a section taken through extrusion mold 78. Formed cheese pieces can be seen in chambers 88. The small amount of cheese passing through the weeper holes 102 has been sheared off as the mold is forced outwardly across the plate by hydraulic cylinder 116. Any cheese extending above the surface of mold 78 has been scraped off by scraper 93. When hydraulic cylinder 104 is energized, ejector plate 106 moves down and ejector fingers force the formed cheese pieces out of mold 78 into a brining trough. 
     Cheese is forced through outlet pipe 22 through outlet 24 at a temperature of 145 deg. Fahrenheit to 150 deg. Fahrenheit, a ph of 5.1 and a pressure of approximately 1000 per pounds per square inch. The mold is filled, and as it is being filled, the UHMW mold cap rises until the cap runners contact the bottoms of the support rails. 
     After the mold is filled, it is moved to a position over the extrusion mold. Hydraulic pressure of 3000 pounds per square inch is used to force the still plastic cheese into forming chambers 88. 
     As the cheese is forced into chambers 88, a skin is formed on each piece, the density of the cheese piece is made uniform and the cheese piece formed in the first mold is worked into a desired internal physical structure. By putting pressure on the cheese block at a separate station, and by extruding the block under great pressure, a uniform density is obtained. 
     The small cheese pieces formed are forced out of the mold into a trough of brine which transports them to a work station. 
     Because of their density, the flexibility of the pieces and their uniform size, the pieces formed can be fed to high speed machines for further processing, such as for breading or to packaging. Because the pieces are brined after being formed they can be brined in minutes instead of hours. 
     The weight of the pieces formed is uniform so they can be sold by the piece, rather than by weight. 
     The prototype device makes small pieces of cheese of uniform shape, at a rate of cheese input of 2400 pounds per hour. The cheese pieces formed have been of two sizes, rectangular pieces 3 inches long and one half inch one each side, and 3 inch long, five-eighths inches round. Practical sizes that can be made with the device are from less than one ounce to blocks of 1 to 2 pounds, two inch, by 3 inch by 4 inch in dimensions. 
     UHMW is used for the mold cap, the mold rub rails and the extrusion molds. UHMW is a linear polyethylene having a relative viscosity of 2.3 or greater, at a solution concentration of 0.05%, at 135 degrees Celsius in decahydronaphthalene. 
     Nominal weight average molecular weight of UHMW is 3 million or higher. UHMW is highly resistant to sliding abrasion and is chemically inert. 
     LEXAN is a trademark of General Electric Company. The material is a polycarbonate. It is used in this device to make the self-springing scraper. The scraper strips off any cheese extending above the surface of the extrusion mold as the mold is pushed past the scraper. 
     The venting plate is made of acrylic plastic. The plate must exhibit extreme flatness from edge to edge. Acrylic plastic has these properties. 
     The mold plate is reciprocated by a 4 inch diameter, 20 inch stroke, double acting hydraulic cylinder. 
     The extrusion molds are reciprocated by 2 inch diameter, 14 inch stroke hydraulic cylinders. 
     The cheese is forced into the extrusion mold by a six inch bore, 12 inch stroke double acting hydraulic cylinder. The pressure exerted on the cheese is 3100 pounds per square inch. 
     The ejectors are operated by two inch bore, 10 inch stroke double acting cylinders. 
     All hydraulic cylinders are operated with FDA approved hydraulic oil. 
     The device shown is a reciprocating device. The reciprocating device takes up little space and rapidly produces the required pieces, ejecting them into the brine trough. A rotating mold plate having multiple stations has been designed. At one station the mold is filled, at a second station the cheese is extruded into the extrusion mold, at a third station the extrusion mold is cooled, and at another station the pieces are ejected.