Abstract:
A method and apparatus for removing a portion of fat from meat cuts involves placing a meat cut on a longitudinal conveyor, pressing sensor probes into the meat cut to measure the relative thickness of fat and the location of lean in the meat, and then withdrawing the sensor probes from the meat. An electronic signal is transmitted from the sensor to a controller along with an encoder signal to determine the depth from the outer lower surface of the meat cut through a layer of fat in the meat to a layer of lean in the meat. Data taken from the foregoing step determine the desired position of the blade, which removes the appropriate amount of fat to be removed from the meat cut.

Description:
CROSS REFERENCE TO A RELATED APPLICATION 
     This application is a continuation-in-part of Ser. No. 09/552,396 filed Apr. 19, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     In the production of processing meat cuts, such as pork butts, existing specifications require that sufficient fat be removed from the butt to expose six to eight square inches of lean meat, while leaving ⅛th to ¼th of an inch fat cover on the remaining curved surface of the meat cut. 
     Existing machines and methods for achieving the above specification involve safety hazards and inaccurate cutting which results in waste of meat product. Further, more than one trimming operation is normally required to achieve the needed specification. Existing processes are labor intensive. 
     Until now, the process of removing an optimal amount of fat from meat cuts such as pork butts has required a person who makes repeated cuts until the desired amount of lean meat is exposed. Often this results in waste, as it is impossible to tell without cutting into it at what depth the lean starts and the fat stops. 
     Previous attempts at automating this process have met with failure because of the variation in fat cover on the meat cuts. The fat cover on meat cuts typically has a layer of lean running through it, which starts about halfway between the neck and the back which is called the false lean. The fat cover is normally thinnest at the neck edge and fattest at the back edge. It is customary when preparing such meat for sale to remove a wedge-shaped piece of fat in order to expose the “false lean”. Typically in the industry, enough fat should be removed to expose at least six square inches of lean meat while leaving ⅛th to ¼th of an inch of fat cover on the remaining surface. 
     It is therefore a principal object of this invention to provide an apparatus for removing a portion of fat from meat cuts which is safe, accurate, and efficient both from a standpoint of time and labor involved. 
     It is a further object of the invention to provide for the photometric determination of the layers of fat and lean within individual pieces of meat for the purpose of guiding the automated removal of optimal amounts of unwanted material by means of an optical device located within a specially constructed probe. 
     It is a further object of this invention to use either a stationary or movable blade for fat removal in accordance with a predetermined cutting profile. 
     These and other objects will be apparent to those skilled in the art. 
     SUMMARY OF THE INVENTION 
     A method for removing a portion of fat from meat cuts involves placing the meat on a longitudinal conveyor, pressing sensor probes into the meat to measure the thickness of fat and the location of lean therein, and then withdrawing the sensor probes therefrom. An electronic signal is transmitted from the sensor probes to a controller and encoder to determine the depth from the outer lower surface of the meat through a layer of fat therein to a layer of lean. Data taken from the foregoing step determine the desired position of the cutting blade. A predetermined amount of fat is thereupon cut from the meat by the blade. The method is used to determine in meat the layer thicknesses by recording at uniform intervals during the penetration into the meat properties of the reflected light. These properties are mapped against the distance traveled by the probe will show segment thickness. 
     In an alternate form of the invention, data from a sensor is sent to the control mechanism of the cutting blade. This blade may then be moved according to the information provided by the sensor. If a sensor is not used, then the operator determines the fat thickness of the butts he will be removing from and sets the blade at a position. 
     An apparatus for removing a portion of fat from meat cuts includes a frame and at least one sensor probe including fiber optics to permit scanning of the interior of a meat cut penetrated by the probe. Power for moving the probe into the meat is mounted on the frame along with a skinning blade mounted in a path of movement of a meat cut on the frame. 
     A controller on the frame takes data from the sensor probe and determines the linear depth of fat material on the meat cut and lean material in the meat cut. The controller then determines the operating position of the blade and positions the blade to effect the removal of the desired amount of fat. The cutting height of the blade is determined by the sensor. 
     More specifically, a meat piece is conveyed on a conveyor belt towards the cutting device. The frame supports the probes beneath the conveyor of the meat. As soon as the meat rides over the probe path, the meat pauses, an air cylinder activates and the probes penetrate the meat. The optic fibers for reception and transmission of the signals are threaded through the probes. The probes have a probe window at the distal end. An LED sends light through a first set of fibers in the probes. The receiving signals picked up by the receiving optical fibers send a message to the controller which analyzes the signals. The probes take measurements while they are engaged with the meat piece both on the up and the down stroke. After they are withdrawn and the meat piece travels further into engagement with the skinning mechanism. The signal analysis generates a message, which is used by the blade control device to raise or lower the blade from the pulling surface of the skinning mechanism, resulting in the removal of a piece composed primarily of fat. 
     The difference in reflected light properties between the fat and lean muscle is distinct enough that a simple probe containing optical fibers can easily distinguish between them. This information is relayed to a controller which controls the motion of a blade. 
     The controller makes a determination based on the registration of a large number of reflected light properties at intervals of depth in the piece of meat. In addition, all values are inserted into a suitable equation or equation system, which is a multi-variable algorithm for the calculation of layer thicknesses. 
     The multivariable algorithm may include a preset offset distance which accounts for the distance between the cutting blade and toothroll in the minimum cutting position, and a variable offset which can be modified by the operator to customize this product appearance according to this customer specifications. 
     In addition, the algorithm may include other variables to vary the desired cutting depth at different times during the cut. For example, the cutting depth may be decreased during the first one-third of the meat to increase the resulting fat depth on the finished product. During the second one-third of the meat the cutting depth may be at the calculated depth. During the last one-third of the meat, the cutting depth may be increased to remove more fat in that area. 
     The cutting device includes a toothroll, shoe and curved blade holder. The blade holder is fastened to a short section of the shoe. The blade holder provides the desired curved cut, while the shoe/toothroll provides the means to pull the meat through the blade. The blade height adjusting mechanism is actuated electromechanically. The toothroll and exit conveyor drive rotate continuously. The conveyor system must move the meat through the stations, and present it to the cutting device. It indexes, so the meat is stationary when being probed. The conveyor belt is modular to ensure positive indexing. The stations are marked by blue segments on the belt. The stations are a set distance apart. During indexing, the belt accelerates for a set distance, moves at a constant speed a set distance (the approximate length of the meat cut), then decelerates a set distance. The maximum, constant speed of the conveyor is set below the surface speed of the toothroll while the meat is moving through the cutting device. The conveyors must hold the meat securely during probing, and maintain its position through the cutting device so that the depth cut is consistent with the depth measured by the probe. A pivoting, flat top plate positioned just ahead of the blade alternately presses the front end and the back end of the meat into the shoe/toothroll/blade to ensure that the meat gets a good start and finish. An alternate pivoting, curved top plate is used to press the outside edges of the meat into the toothroll for better cuttinq performance. 
     In an alternate form of the invention, once the blade has been set the meat advances on the conveyor into contact with the blade. The blade mechanism then follows a predetermined arcuate path. This path is based on the measured fat thickness or operator setting and reflects the statistical average of fat covering the butt, which has been determined by the inventors. 
     The cutting device includes a toothroll, shoe and curved blade holder. The blade holder is curved to cut an arcuate line through the butt perpendicular to the direction of travel. The blade holder is fastened to a short section of shoe. The blade holder provides the desired curved cut, while the shoe/toothroll provides the means to pull the meat through the blade. The blade height adjusting mechanism is actuated electromechanically. This allows the thickness of the fat plate removed to vary from front to back and side to side. The gripper roll and exit conveyor drive rotate continuously. 
     The infeed conveyor system must move the meat through the stations and present it to the cutting device. The infeed conveyor at its maximum, constant speed is set slower than the gripper roll. This speed differential helps to manipulate the meat piece over the shoe and blade system for accurate fat removal. The speed differential preserves the profile of the meat by compensating for any resistance at the blade. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side elevational view and partial sectional view of the apparatus of this invention; 
     FIG. 2 is an enlarged scale layout of the power train of the apparatus of FIG. 1; 
     FIGS. 3A-3D are schematic elevational views showing the sequential steps of the method of this invention as practiced on the apparatus of this invention; 
     FIG. 4 is an enlarged scale perspective view of the cutting station of the device in FIG. 1; 
     FIG. 4A is an enlarged scale side elevational view of the cutting station as shown in FIGS. 1 and 2; 
     FIG. 5 is an elevational view at an enlarged scale showing one of the probe sensors; 
     FIG. 6 is an enlarged scale side elevational view of the apparatus at the sensor station of this invention; 
     FIG. 7 is a plan view of the blade holder and blade of FIG. 4; 
     FIG. 7A is an enlarged scale sectional view taken on line  7 A- 7 A of FIG. 7; 
     FIG. 8 is a partial rearward elevational view of the blade and blade holder of FIG. 7 when the blade holder is in a horizontal position; 
     FIGS. 9 and 10 are similar to FIG. 8 but show the apparatus tilted in opposite directions under different conditions; 
     FIG. 11 is a plan view of a piece of meat on a conveyor; 
     FIG. 12 is a sectional view taken on line  12 - 12  of FIG. 11; and 
     FIG. 13 is a sectional view taken on line  13 - 13  of FIG.  11 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The machine  10  has a frame  12 , (FIG.  1 ), with a loading station  14 , a probing station  16 , a waiting station  18 , and a skinning station  20  (FIGS.  3 A- 3 D). 
     With reference to FIG. 2, a conveyor belt  22  is mounted on frame  12  and has a top horizontal portion  24 . A horizontal transverse roll  26  is mounted adjacent the loading station  14  to support and reverse the direction of conveyor belt  22 . The belt  22  then extends to roll  28  and extends therearound and departs in a downwardly direction towards roll  30 . A conventional piston-belt-type tightener  31  is associated with roll  30  to selectively tighten or change the attitude of belt  22 . 
     The belt  22  then departs roll  30  and extends upwardly and forwardly to roll  32  which is slightly below and forwardly of roll  34 . The belt extends around roll  32  and thence rearwardly and then again forwardly as it extends around roll  34 . The belt then extends to forward roll  36  and departs roll  36  back in a horizontal direction towards the point beginning at roll  26 . A motor  38  (FIG. 2) is mounted on frame  12  and is connected by belt  39  to the roll and drive pulley  34  via pulley  40  on the motor. 
     With reference to the upper portion of FIG. 2, a chain  42  extends from roll and drive pulley  34  upwardly around a roll and drive pulley  44 . A conveyor belt  46  extends around roll  44  and departs therefrom in a forwardly and downwardly direction to extend around roll  48 . The belt  46  then extends rearwardly to extend around roll  50 , and departs roll  50  in a forwardly horizontal direction. Belt  46  engages a plurality of rolls  52  which are mounted on the lower end of piston assemblies  54  which are mounted on downwardly extending brackets  56 . Air piston  58  is parallel to the vertical air pistons  54  and is operatively connected to roll  50 . Pistons  54  and  58  serve to raise and lower the belt  46  with respect to the horizontal portion  24  of belt  22  which extends thereunder. Belt  46  then extends forwardly from rolls  52  to extend around plate  126 , whereupon the belt then extends rearwardly and upwardly to its point of beginning at roll  44 . A conventional piston-belt tightener  61  (FIG. 2) is associated with roll  48  to facilitate the adjustment of the tension on conveyor belt  46 . Roll  48  serves also as a pivot point for the upward and downward movement of the belt  46  by the pistons  54  and  58 . The lower horizontal train of belt  46  as seen in FIG. 2 is identified by the numeral  62 . 
     A motor  64  is mounted on frame  12 , (FIG.  2 ), and has an output drive pulley  66 . A belt  68  extends from pulley  66  and extends forwardly and upwardly to extend around pulley  70 . The belt  68  then extends rearwardly and downwardly around pulley  72 , and thence upwardly and forwardly around a drive pulley (not shown) on gripper roll  74  which is a part of the skinning station  20  as will be discussed hereafter. 
     Brackets  76  (FIG. 4) are spaced apart and are secured to frame  12  and are pivotally secured to arm  78  by the rearward ends of the arms through the function of conventional connecting pins  79 . A vertical arm segment  80  extends upwardly from the forward end of the arm  78  (FIGS.  2  and  4 ). A transverse rod  82  extends between the upper ends of arm segments  80 . Separate springs  134  are secured to the rod  82  and extend forwardly to frame  12  to yieldingly prevent the upward pivotal movement of arms  78  on pins  79 . 
     A pair of control arms  86  (FIG. 4) are attached at their lower ends to sleeve  88  (FIG. 2) which are mounted on rotatable cams (not shown) which can raise or lower the control arms. Shoe mounts  90  are an integral part of arms  86  and conventionally are connected to the ends of the shoe  96 . (FIG.  4 ). A blade  94  (FIGS. 3C and 3D) is secured to the blade holder  92  and shoe  96  and is conventionally associated with arcuate-shaped shoe  96  to perform the skinning operation (FIGS.  3 C and  3 D). 
     As shown in FIG. 2, a piston assembly  98  is shown in the lower portion of that figure and is vertically disposed and is operatively connected to bracket  100 . Three probe sensors  102  are vertically disposed on bracket  100  and extend upwardly therefrom and terminate in elongated probe spikes  104  (FIGS.  5  and  6 ). The spikes terminate at their upper ends in points  106 . Each spike has a window opening  108 . As shown in FIG. 5, two sets of optical fibers  110  and  112  extend through probes  102  and spikes  104  and terminate immediately adjacent the window opening  108 . Optical fibers  110  are connected to a source of light in the sensor  102  to illuminate the area just outside the spike and outside the window opening  108 . Optical fibers  112  have the ability to receive light that is reflected from the lean and fat portions of the meat cut being treated. The light coming from fibers  110  and reflected onto the fibers  112  from the lean and fat surfaces are returned to sensor  102  which sends a signal through lead  114  (FIG. 5) to a controller  116  (FIG. 2) including a computer. With reference to FIGS. 2 and 6, a lead  118  connects controller  116  with the piston assembly  98 . Lead  120  extends from controller  116  to a slidable door  121 /A and linear actuator  121  (FIGS. 2 and 3C) located just forwardly of loading station  14 . Lead  120  also connects controller  116  to pistons  54  and  58 . Lead  122  connects controller  116  with motor  38  (FIG.  2 ). Lead  124  connects controller  116  with motor  64 . 
     With reference to FIG. 4A, a top feed plate  126  of rectangular and generally flat construction is rotatably supported by ears  128  on arm  78  (FIG.  4 ). An encoder (not shown) measures the position of the probes and transmits this measurement to the controller. Pins  129  effect the pivotal connection between plate  126  and the ears  128 . Feedplate  126  has a leading end  130  and a trailing end  132 . A spring cylinder  134  has an upper end that hooks on rod  82  and a lower end secured to the frame  12  and serves to hold feedplate  126  down on the meat cut. 
     The feedplate  126  is normally in the horizontal position shown by the solid lines in FIG.  4 A. The lead end  130  pivots upwardly as the meat product endeavors to pass thereunder on conveyor  24 . This causes the trailing end  132  to move to a level lower than the pin  129  whereupon it exerts force on the meat product as that product moves into contact with the gripping roll  74  and the blade  94 . The continued longitudinal movement of the meat towards the blade then causes the meat product to push upwardly on the depressed trailing end  132  which causes the plate  126  to move to the position shown in FIG. 4A where the end  130  is depressed or lowered. The engagement of the product by the lower end portion  130  of the plate member serves to exert additional longitudinal boost to the meat product as it is moving upwardly and over the blade  94  and gripping roll  74  at the skinning station  20 . 
     In operation, a meat cut A (FIG. 3A) is placed on the conveyor belt  22  at the loading station  14 . The controller  116  has the ability to index the movement of conveyor  22 , and the conveyor is motionless at this point in time. The door  121  is in an open position. The bracket  100  is in its lower position shown in FIG. 3D so that the probe spikes  104  are withdrawn and the points  106  of the spikes  104  are at a level below the lower horizontal portion  24  of belt  22 . 
     The controller  116  thereupon actuates motor  38  to cause conveyor belt  22  to advance in a clockwise direction as seen in FIG. 2 whereupon the meat cut A is moved to the probing station  16  (FIG.  3 B). The controller then closes door  121 A, and actuates the piston assembly  98  which causes the bracket and sensors  102  to rise whereupon the probe spikes  104  penetrate the meat cut A as shown in FIG.  3 B. The pistons  54  and  58  are also actuated by the controller  116  to press down on the meat cut A as shown in FIG. 3B while the probe spikes  104  are penetrating the meat A. At the same time, meat cut B can be placed on the loading station  14 . 
     The probe spikes move quickly upwardly and thence downwardly out of the meat product. The sensor  102  works in the manner described and permits the optical fibers  112  to receive the reflected light from optical fibers  110  through the window opening  108 , with the reflected light having varying properties depending on whether the light is reflected from fat or lean meat. A signal from the reflected light through fiber optics  112  is transmitted through line  114  to controller  116  and the encoder (not shown) so that the relative thickness of the fat and lean meat is determined by the controller. Obviously, the conveyor  22  is motionless during the time when the meat cut A is penetrated by the probe spikes  104  at the probing station depicted in FIG.  3 B. 
     The probe spikes  104  move quickly into and out of the meat cut and assume the position generally shown in FIG. 3A at a point below the conveyor belt  22 . The controller  116  then opens the door  121 , and advances the conveyor belt  22  to the position shown in FIG. 3C where the meat cut A is moved to the waiting station  18 , and the meat cut B is moved from the loading station  14  to the probing station  16 . A new meat cut C can be placed at the loading station  14  during this same period of time. FIG. 3D shows how the controller  116  further indexes the conveyor belt  22  after the above described description of the components in FIG.  3 C. This causes the meat cut A to move to the cutting station  20 ; the door  121  opens to receive the meat cut C; and the meat cut B moves towards the waiting station  18 . It should be noted that the controller also causes the lower horizontal portion  62  of belt  46  to engage the top meat product A as it moves into the cutting station (FIG.  3 D). At the same time, the feedplate  126  engages the meal cut A and performs its boosting function of pushing the meat A through the skinning station as described heretofore. 
     Critical to the foregoing process is that the controller  116  receives a signal generated from fiber optics  112  to cause the blade  94  to cut the meat cut A passing through the skinning station  20  at a sufficient depth that the fat will be removed at a depth to expose at least six square inches of lean meat. The blade  94  will be at the appropriate depth by virtue of the measurements of sensor  102  transmitted to controller  116  and the encoder (not shown) to cause the blade  94  to be at a depth calculated by the controller. The controller carries out a calculation and transmits a signal to cause a cam shaft (not shown) to rotate within sleeves  88  causing blade arms  86  to adjust the height of blade holder  92  and blade  94  to a depth with respect to gripper roll  74  to cause the blade to be positioned at the correct height. 
     Description of an Alternate Embodiment 
     The preceding principal embodiment contemplates that the cutting blade  94  is moved to its designated cutting height in response to data from the probes, and remains in a stationary or constant position during the cut being made on the meat piece so probed. The alternative embodiment of the invention contemplates that the lateral attitude and/or the height may vary as the cut is being made so that the lateral and/or side profiles of the cut may vary during the cutting action. 
     The controller  116  (FIG. 2) can be loaded with profile cuts calling for varying blade heights during a given cut. These “memory” cuts are based on substantial historical data based upon a plurality of cuts of similar pieces of meat. Each cut A (FIG. 3A) is programmed to start with the blade  94  at approximately ⅛th inch in height. The probe  102  or sensor then signals the controller  116  as to the depth of cut the blade needs to make based upon the depth of fat that dwells below either the false lean layer  136 , or the primary lean  138  (if there is no false lean). The controller  116  thereupon actuates the height adjustment mechanism of the blade and gradually raises the blade height as it proceeds through the longitudinally moving piece of meat. Thus, the blade will follow the cutting profile to an increased depth shown by the dotted line  140  in FIG.  12 . Based upon historical data, the line  140  will be substantially horizontal as it approaches and passes the lower surface of false lean layer  136 . The controller  116  knows to so control that center portion of line  140  because of data sensed by one or more probes  102 . Again, based upon historical data, the controller causes the blade  94  to move from the horizontal plane of movement after the cut on line  140  moves beyond the false lean layer  136  to a deeper cut shown by the left hand end of cutting line  140  in FIG.  12 . This terminal end  140 A of line  140  is normally at the maximum cutting depth of the machine. 
     If more than one probe  102  is used to evaluate a single lab of meat, the controller  116  can adjust the height of the cutting blade  94  at more intervals along the cutting line  140 . The ability of the blade  94  to have a varying cutting height during the cut on a given piece of meat, (as compared to the blade having a fixed height during such a cut) means that more fat can be eliminated by increasing the depth of cut in areas of thicker layers of fat, thus substantially increasing the yield of lean meat versus fat for each piece of meat. 
     FIGS. 7-10 show in more detail the blade holder  92  and blade  94  of FIG.  4 . One end  92 A of blade holder  92  is curved upwardly to accommodate the natural curve and thickness of a shoulder butt. On certain cuts of meat, greater amounts of fat can be trimmed if the blade holder and blade can have their opposite ends raised with respect to each other. The profile of the cutting blade from this perspective can also be imposed on the memory of a controller  116  to cause the tilting of the blade as shown in FIGS. 11 and 12. (See FIGS. 9 and 10.) 
     It is therefore seen that this invention will achieve at least all of its stated objectives.