Abstract:
A patty-displacing end portion is provided for a plunger for a food patty-molding apparatus, the apparatus comprising an apparatus frame, a mold plate, the plunger and a heating element. The mold plate has at least one cavity and is mounted to move with respect to the frame in a direction to position the cavity between a fill position wherein the cavity is filled with food product material to form a molded patty, and a molded patty knockout position. The plunger is arranged to move vertically into the cavity to dislodge or knock the olded patty out of the cavity. The plunger has a body and raised formations or standoffs extending down from the body, the raised formations being numbered and positioned to be spread out over the body. The number and position of the raised formations provides a decreased contact pressure on the patty being dislodged.

Description:
[0001]    This application claims the benefit of U.S. Provisional Application No. 61/564,702, filed Nov. 29, 2011. 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0002]    The present invention relates to food patty-molding machines. The invention particularly relates to food patty-molding machines which incorporate a moving old plate having one or more patty-forming cavities which are filled to form patties, and then emptied by action of one or more knockout plungers, the patties being discharged to a patty-receiving area. 
       BACKGROUND OF THE INVENTION 
       [0003]    Food patty-forming or molding machines are described, for example, in U.S. Pat. Nos. 7,255,554; 8,011,914; 6,454,559; 6,368,092; 3,887,964; 4,372,008 and 4,821,376. A known food patty-forming machine or apparatus  20  is illustrated in  FIG. 1 . This machine is described in detail in U.S. Pat. No. 3,887,964 and has been marketed as the FORMAX F-26 machine by Formax, Inc., of Mokena, Ill. Molding machine  20  includes a machine base  21  which supports the operating mechanisms of the machine and contains hydraulic actuating systems, electrical actuating systems, and most of the machine controls. 
         [0004]    The food patty-molding machine  20  includes a supply mechanism  24  for storing and supplying a moldable food product ;  such as ground beef, fish, pork ;  chicken, potatoes, or the like, to the processing mechanisms of the machine. Supply mechanism  24  includes a large food product storage hopper  25  that supplies a food pump system  26 . System  26  includes two alternately operating food pumps (one shown); other machines typically include only a single food pump. The two food pumps continuously pump food, under pressure, into a valve manifold connected to a cyclically operable molding station  28 . Molding station  28  includes a multi-cavity mold plate  32  that moves cyclically between a fill position, as shown in  FIG. 1 , and a discharge position ire which its mold cavities are outside of station  28 , aligned with a set of plungers having patty-displacing end portions in the form of knockout cups  33 . The cups are sized and shaped to be slightly smaller than, but to closely conform to, the cavities in the mold plate. 
         [0005]    Food supply mechanism  24  includes a conveyor belt  31  that extends completely is across the bottom of hopper  25 . In  FIG. 1 , a limited supply of food product  38  is shown in hopper  25 ; a much greater supply could be stored in the hopper without exceeding its capacity. The forward end of hopper  25  communicates with a vertical hopper outlet  39  that leads downwardly into two pump chambers; only one pump chamber  69  is shown. Three motors drive three vertical feed screws. Only one motor  47  and one feed screw  3  are shown in  FIG. 1 . 
         [0006]    The upper part of a pump housing  71  comprises a plate  81  that supports the mold plate  32 . The mold plate  32  includes a plurality of individual mold cavities  86  distributed in a single row or multiple rows across the width of the mold plate; mold cavities  86  are alignable with the manifold outlet fill passage  79 . A mold cover  82  is disposed immediately above mold plate  32 , closing off the top of each of the mold cavities  86 . The mold cover  82  may include a conventional breather plate. Suitable spacers (not shown) are provided to maintain the spacing between the cover  82  and the support plate  81 , essentially equal to the thickness of the mold plate  32 . A housing  88  is positioned over the cover plate  82 . The housing  88  encloses the operating mechanism (not shown) for reciprocating the knockout cups  33 . 
         [0007]    In the operation of the patty-molding machine  20 , a supply of ground meat or other moldable food product  38  is placed into the hopper  25 , and is advanced toward the hopper outlet  39  by the conveyor  31 . Whenever one of the food pump plungers, such as the plunger  68 , is retracted to expose a pump cavity (e.g., the cavity  69 ), the vertical feed screws  53  aligned with that pump cavity are actuated to feed the food product into the pump cavity. 
         [0008]    In  FIG. 1 , pumping system  26  is illustrated with the mold plate  32  in its fill position, and with the pump  61  pumping the moldable food product through the manifold  27 . The pump  61 , as shown, has just begun its pumping stroke, and has compressed the food product in pump cavity  69 , forcing it under pressure into the manifold  27 . As operation of the machine  20  continues, the plunger  68  advances and food product flows into the mold cavities  126 , there is a relatively constant pressure on the food product and chamber  69 , manifold  27 , fill passage  79 , and cavities  86 . 
         [0009]    In each molding cycle, mold plate  32  remains in this fill position for a limited dwell interval. As the mold cavities  86  move into the fill position, one of the two food pumps of machine  20  pumps food product through manifold  27  and fill passage  79 , filling the mold cavities. To assure complete filling of the mold cavities, the food pump must apply a substantial pressure to the food product. 
         [0010]    Following the fill dwell interval, mold plate  32  is moved outwardly, to the right from its fill position, as shown in  FIG. 1 , until it reaches a discharge position with its mold cavities  86  aligned with knockout cups  33 . As mold plate  32  moves toward its discharge position, mold cavities  86  all move dear of fill passage  79  before any part of those cavities projects out of mold station  28 , beyond support plate  81  and cover  82 . Thus, the food pump in machine  20 , as shown in  FIG. 1 , remains sealed off at all times. A second dwell interval occurs at the discharge position of mold plate  32 , during which knockout cups  33  move downwardly through the mold cavities, discharging the molded food patties onto a patty-receiving area, e.g. a take-off conveyor (not shown). 
         [0011]    The knock out cups are typically concave cups each having a surrounding edge, typically 3/32 inch thick, which presses on an outside circular perimeter of the patty to dislodge the patty from the mold plate. 
         [0012]    Following discharge of the molded food patties, mold plate  32  is moved back toward its fill position so that mold cavities  86  can again be filled with food product. Again, mold cavities  86  are completely inside molding mechanism  28 , sealed off, before they come into alignment with the fill passage  79 . 
         [0013]    For some food products a radiant heating element (not shown in  FIG. 1 ) is used to heat the knockout cups  33  to an elevated temperature of between 180-210° F. in order to liquefy the fat in the food product, thereby facilitating release of patties from the cups at the bottom of knockout cup travel. 
         [0014]    The present inventors have recognized that on occasion, depending on the product, the perimeter of the heretofore known knockout cup can cause an indentation on the perimeter of the patty which is visible after cooking. The present inventors have recognized that it would be desirable to provide a knockout plunger for a patty-forming apparatus that did not cause a visible irregularity in cooked patties. The present inventors have recognized that it would be desirable to provide a knockout cup for a patty-forming apparatus that was cost effectively produced and that would be durable in operation. 
       SUMMARY OF THE INVENTION 
       [0015]    The present invention provides an improved plunger for a food patty-forming apparatus having a mold plate with mold cavities adapted to be filled with food product to form patties, wherein the patties are removed from the cavities by action of the plunger. Preferably, the patty-displacing end portion has a perimeter that closely matches an inside perimeter of the cavity. The improved plunger includes plural, spaced-apart raised portions or standoffs on a bottom surface thereof that press on a top surface of the patty to dislodge the patty from a mold plate. 
         [0016]    The standoffs have sufficient surface area to minimize surface pressure on the patty to avoid indentations or alternately, leave spaced-apart isolated indentations that visually blend into the typical irregular texture of the patty product. 
         [0017]    Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention and the embodiments thereof, from the claims and from the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a diagrammatic sectional view of a prior art food patty-molding machine; 
           [0019]      FIG. 2  is a diagrammatic fragmentary perspective view of a portion of a food patty forming machine incorporating the improvement of the present invention; 
           [0020]      FIG. 3  is a diagrammatic sectional view of a food patty-forming apparatus according to the present invention, with the apparatus mold plate in a knockout position; and 
           [0021]      FIG. 4  is a bottom perspective view of a plunger taken from  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0022]    While this invention is susceptible of embodiment in many different forms, there are shown in the drawings, and will be described herein in detail, specific embodiments thereof with the understanding 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 embodiments illustrated. 
         [0023]      FIG. 2  illustrates a modified food patty-forming apparatus  120  of the present invention. Except as otherwise described herein, the apparatus  120  can be of a reciprocating type such as described in U.S. Pat. Nos. 7,255,554; 8,011,914; 6,454,559; 6,368,092; 3,887,964; 4,372,008 and 4,821,376, herein incorporated by reference, or a rotary type as described in U.S. Ser. No. 13/187,426, filed Jul. 20, 2011. Like components compared to the components of the prior art apparatus of  FIG. 1  carry like reference numerals. 
         [0024]    The apparatus  120  includes a mold plate  32  that moves cyclically between a fill position as shown in  FIG. 1  and a discharge or knockout position as shown in  FIG. 3 . In the discharge position, a row of food patties  130  which occupy mold cavities  86  within the mold plate  32 , are discharged by downward movement of a row of knockout plungers  133 . The food patties  130  can be delivered to a take-off conveyor  135  such as shown in  FIG. 3 . 
         [0025]      FIG. 2  illustrates a knockout mechanism  140  that includes two knockout drive units  142 ,  144 . The drive units  142 ,  144  can be configured in various known fashions such as those described in U.S. Pat. Nos. 7,255,554; 8,011,914; 6,368,092; 4,768,260; or 3,887,964, or U.S. Ser. No. 13/187,426, filed Jul. 20, 2011, all herein incorporated by reference. Each drive unit  142 ,  144  can include a rod housing  145  within which a reciprocating knockout rod  147  is at least partially enclosed. Each knockout rod  147  can be fastened to a knockout bar assembly  148 . 
         [0026]    A plurality of knockout support blocks  150  are mounted to a bottom side of the bar assembly  148  spaced apart along a length of the bar assembly. Each block  150  mounts one of the plurality of the knockout plungers  133 . The number and spacing of knockout plungers  133  corresponds to the number and location of the plurality of the cavities  86 , that are arranged in rows across a width of the mold plate  32 . 
         [0027]    A radiant electric heater  160  circumscribes the two knockout rods  147  and is located at an elevation approximately equal to the bar assembly  148  when fully elevated at the top of its reciprocating stroke. A heat deflector shield or hood  162  (shown in fragmentary fashion in  FIG. 3 ) directs heat from the heater  160  to the plungers  133 . The heater  160  is configured to heat the knockout plungers to an operating temperature of 180-210° F. depending on the food material being formed in order to assist in dislodging of the patties from the mold plate and to prevent sticking to the plungers. A rheostat (not shown) is wired to the heater element  160  to manually set the temperature of the plungers  133 . A more sophisticated control system using a temperature sensor and an automatic adjustment can also be used. 
         [0028]      FIG. 3  illustrates the apparatus  120  with the mold plate  32  in the discharge or knockout stage or position. The knockout plungers  133  are shown in a downward position, having just discharged patties  130  from cavities  86  respectively. The patties  130  can be deposited on the product conveyor  135  to move to a collection area for packaging. 
         [0029]      FIGS. 3 and 4  illustrate the configuration of the plungers  133 . According to one embodiment of the invention, the plunger  133  can be composed of aluminum with a USDA compliant coating, or acetyl copolymer or stainless steel. The acetyl does not need a coating. The stainless steel version could be used with or without a coating. The plunger  133  includes a plunger body  220 . Each plunger  133  can be fastened to the respective support block  150  using a pair of fasteners  166  that are inserted through holes  222 ,  224  through the body  220 . 
         [0030]    The size and shape of the plunger body  220  is in direct relation to the patty size. Depending on the size of the product to be knocked out, the plunger body  220  could be as small as 2 inches in diameter or as large as 4 inches by 6 inches. A circular disc shaped plunger body  220  is shown in the figures. 
         [0031]    A plurality of raised formations, such as pins or standoffs  230  extend downwardly from a bottom surface  234  of the body  220 . Each raised formations or standoff  230  has a flat distal surface  230   a.  According to the illustrated embodiment, each raised formation  230  is in the form of a tapered post or pin that is tapered from a base end  230   b  on the body  220  to the distal end  230   a.  The base end  230   b  can be mounted on, formed with, or connected to ;  a reinforcing pad  230   c  on the bottom surface  234  of the body. During knockout of a product from the mold plate, the body is moved downward to the mold cavity and the flat distal surfaces  230   a  of the plural standoffs  230  push the patty from the mold plate. The raised formations or standoffs  230  are numbered such that the aggregate surface area of the distal surfaces  230   a  decreases the contact pressure by any one of the standoffs  230  during pressing of a patty to dislodge the patty from the mold plate. Additionally, the number and spacing of the standoffs  230  over the surface of the body  220  are such that any surface mark caused by the standoffs on the patty being dislodged will be hardly noticeable given the typical irregular texture of the patty material. 
         [0032]    Traditional cups impact the product just inside of the mold cavity edges around the entire perimeter of the cavity. Since products are typically softer around the edges, the knockout cups can leave an impression in the product due to the force of the impact. The impact impression can be unattractive to some customers. By using spaced-apart standoffs  230  the knockout force is dispersed throughout more of the product top surface. In some applications, the standoffs can be spaced inward from the perimeter of the product to be knocked out by 1/16 inch or greater to prevent damage to the softer surrounding edge of the product to be knocked out. Also, traditional cup-shaped knockout cups, with contact only around the perimeter of the portion to be knocked out, allow the center of the portion being knocked out to bulge up into the empty center space of the knockout cup, causing negative effects such as stretching and/or cracking, especially on thin portions. The standoff locations inward of the perimeter of the knockout cup could prevent this bulging effect, allowing the patty to remain flatter throughout the knockout process. Although a flat disc shaped body  220  is shown, the standoffs  230  may also be used together with the existing ::perimeter“” or cup design to provide effective knockout with minimal portion marking and/or distortion. According to this design, multiple standoffs within the traditional knockout cup, and the perimeter of the knockout cup both knock out the product. 
         [0033]    The number of standoffs  230  would be determined by multiple variables such as portion weight, portion thickness, product density and product texture. A minimum number of standoffs would be desired in order to minimize the contact area with the product yet provide effective knockout. 
         [0034]    When the area of the bottom surface  234  is substantially equivalent to the top surface of the patty to be knocked out, an exemplary range of aggregate surface area of the distal surfaces  230   a  to the gross area of the bottom surface  234 , which includes the area occupied by the pins  230  and pads  230   c,  can be between 1% and 10%. Stated another way, an exemplary range of aggregate surface area of the distal surfaces  230   a  to the area of a top surface of the patty to be knocked out, can be between 1% and 10%. The standoffs  230  can be spaced apart evenly on the bottom surface  234  or can be spaced apart unevenly depending on the product properties and test results. Advantageously, the height of the standoffs  230  on a given plunger are such that the distal surfaces  230   a  reside in a single plane, although the invention encompasses standoffs of varying heights and residing in multiple planes in a single plunger. Where the standoffs extend from a single planar bottom surface  234 , an equal standoff height “h” defines a single plane for the distal surfaces  230   a.  According to exemplary embodiments, a height “h” of the single plane of the aggregate distal surfaces  230   a  of the standoffs  230  could vary between about 1/16 inch for some knockout applications to about 2 inches for other knockout applications. The reason for the height range is that the plunger body can act as a deflector, shielding the product to be knocked out from heat and moisture. In cases where this deflecting action is desired, very short standoffs would be used in order to get the plunger disc very dose to the product to be knocked out. In other cases where the deflecting action is not desired, longer standoffs can be used to move the plunger disc away from the surface of the product to be knocked out. According to exemplary embodiments, the number of standoffs can vary with an anticipated density of 1 to 10 standoffs per square inch of the top surface of the product to be knocked out. 
         [0035]    From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred.