Abstract:
The automatic fillet-trimming machine comprises a first conveyor belt that is capable of registering the weight of the individual fillets, one or more computer-controlled cameras or other imaging means that identifies and localizes the undesired portions of a fish fillet to be removed, a height-measuring apparatus the registers the thickness of the fillets, a second conveyor belt that comprises suction means for securely holding the fillets, and which transports the fillets to a plurality of computer-controlled cutting devices, the movement of which is directed according to coordinates received from the imaging means, and means for weighing and removing waste products.

Description:
This application claims the benefit of Provisional application Ser. No. 60/330,841, filed Nov. 1, 2001. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to a machine and method for the automated trimming of fish fillets, including the removal of undesired tissue, for example fat tissue, discoloured tissue and any other undesired portions of a fish fillet. 
   Fish of the salmon family are characterized in that fatty tissues are quite distinct in relation to the meat. After the fish has been filleted, a significant amount of fatty tissues, discoloured tissues as well as fins and bones must be removed in order to achieve a quality product. During the initial filleting process, the head and backbone are removed from the fish, and the fish is divided into two fillets. U.S. Pat. No. 5,591,076 discloses an apparatus for the automatic processing of whole flatfish, wherein the dorsal and ventral fins are removed from the fish. This known device does not, however, provide for the trimming of fatty tissues from the resulting fillets. 
   Various attempts have been made at the automatic removal of fatty tissues from the surface of fish fillets. These attempts have heretofore provided unsatisfactory results. Consequently, the trimming of fish fillets continues to be done manually. 
   It is generally known to use a freezing drum to remove the skin and the fatty layer immediately beneath the skin from a fish fillet. In devices of this nature, the fillet is frozen skin-side down to the drum. A horizontal band knife is then used to slice the fillet, leaving the skin and the layer of fat attached to the drum. While this technique is adequate for removing the skin, it is unsatisfactory for the removal of layers of fat from the opposite side of the fillet. This is because the meat-side of the fillet does not have a flat profile, as is the case with the skin side. On the meat-side of the fillet, the dorsal edge and the ventral edge (which both contain layers of fat) are significantly lower than the thickest region of the fillet. The above-described technique would thus remove an excessive amount of meat from this thick portion. 
   The machine from U.S. Pat. No. 5,779,531 attempts to solve this problem by providing rollers that press the fillet against a conveying surface in order to flatten the fillet. 
   Again, this technique is intended primarily to remove the surface layer from the skin-side of the fillet, and is incapable of flattening the fillet to the degree necessary for the effective removal of fatty tissues from the meat-side. 
   It is known to use devices comprising brushes to remove fat from the meat-side of a fillet, however machines of this type produce a rough and unattractive surface. 
   SUMMARY OF THE INVENTION 
   The present invention provides for an apparatus and method that overcome the above-described problem of removing fatty tissues from the meat-side of a fish fillet, as well as providing for the completely automated trimming of fish fillets. 
   The automatic apparatus and method according to the invention comprises an operator interface, an order-handling system and the automatic fillet-trimming machine. The operator interface comprises an operator panel mounted on or near the trimming apparatus. The operator panel provides means whereby the operator can calibrate the apparatus, input and/or reset the various parameters of the system. 
   The order-handling system is a computer-controlled system in communication with the trimming apparatus whereby specific instructions from a customer can be registered and performed, such as the total weight or number of fillets to be trimmed, specific instructions regarding the type of trimming to be performed, etc. 
   The automatic fillet-trimming machine comprises a first conveyor belt that is capable of registering the weight of the individual fillets, one or more computer-controlled cameras or other imaging means that identifies and localizes the undesired portions of a fish fillet to be removed, a height-measuring apparatus the registers the thickness of the fillets, a second conveyor belt that comprises suction means for securely holding the fillets, and which transports the fillets to a plurality of computer-controlled cutting devices, the movement of which is directed according to coordinates received from the imaging means, and means for weighing and removing waste products. 
   The camera-system of the invention, which is generally known in the art, comprises a computer that calculates the coordinates of the various cuts to be performed based upon the color difference between the meat portions of the fillet and the fatty portions. The computer is connected to a control unit that controls a plurality of cutting devices that remove the undesired portions. 
   The cutting devices of the invention perform both vertical and horizontal cuts. The vertical cuts remove undesired portions from the trailing end of the fillet, as well as undesired tissue along the fillet&#39;s periphery. The horizontal cuts remove layers or patches of fat from the surface of the fillet. In order to perform the horizontal cuts, the apparatus comprises means for lifting the dorsal and ventral edges of the fillet to the height registered by the height-measuring apparatus in order to present a horizontal plane for cutting. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be described in detail with reference to the following figures, wherein: 
       FIG. 1  is perspective view of a fish with the head removed. 
       FIG. 2  is a perspective view of the fish from  FIG. 1 , showing a cross-section of the muscle structure. 
       FIG. 3  is a perspective view of a fish fillet laying on a flat surface. 
       FIG. 4  is a perspective view of the fillet from  FIG. 3 , with the dorsal edge having been lifted in order to provide a horizontal surface ideal for cutting. 
       FIG. 5  is a vertical cross-section of a fillet in the dorsal-to-ventral direction, showing the location of fat regions and the dorsal edge cut A and ventral edge cut C. 
       FIG. 6  is a lengthwise, vertical cross-section of a fillet showing a fat region and the location of the tail cut B. 
       FIG. 7  is a perspective view of a fillet showing the location of the tail cut B. 
       FIG. 8  is a perspective view of a fillet showing the location of the vertical cut A along the dorsal edge. 
       FIG. 9  is a perspective view of a fillet showing the location of the vertical cut C along the ventral edge. 
       FIG. 10  is an overhead view of a fillet showing the regions of fat along the dorsal and ventral edges. 
       FIG. 11  is a perspective view of the apparatus according to the invention. 
       FIG. 12  is a perspective view of a cutting mechanism for performing vertical cuts along the dorsal edge. 
       FIG. 13  is a perspective view of a cutting mechanism for performing the tail cut. 
       FIG. 14  is a perspective view of a cutting mechanism for performing vertical cuts along the ventral edge. 
       FIG. 15  is a perspective view of a cutting mechanism and lifting means for performing a horizontal cut along the dorsal edge of a fillet. 
       FIG. 16  is a perspective view of a cutting mechanism and lifting means for performing a horizontal cut along the ventral edge of a fillet. 
   

   DETAILED DESCRIPTION 
   The automatic fillet-trimming machine according to the invention comprises two trimming lines, one for the right-hand and one for the left-hand fillets.  FIG. 11  shows a machine for a right hand fillet. As shown in  FIG. 11 , each line of the automatic trimming machine according to the invention comprises two conveyors  20  and  22  for transport of fish fillet. A weighing means  26 , which is located under conveyor  20 , registers the weight of the fillet. After being weighed, the fillet is transported under a camera  28  or other appropriate imaging means. Camera  28  generates an image of the fillet and image-analysis software identifies the undesired tissue to be removed, and the camera computer program calculates the five individual cuts to be performed. The five cutting coordinates are then sent to a control unit  32 , which controls a plurality of cutting mechanisms. An operator interface panel may be used to manually input or adjust the various parameters of the system as needed. A height measuring unit  24  registers the height of the fillet along its length and communicates this measurement to control unit  32 . Height measuring unit  24  is preferably a photo cell device, however any appropriate-method for registering the thickness of the fillet, and communicating this measurement to control unit  32  would suffice. 
   In order to appreciate the function of the invention,  FIGS. 1–10  show the body parts and other areas of interest of a fish of the salmon family, and its fillet, as well as the various cuts that are performed by the machine according to the invention. The body parts and other areas of interest include:
         Dorsal Fin:  1     Fat fin:  2     Collarbone:  3     Thick dorsal meat region:  4     Dorsal edge fat strip:  5     Dorsal region surface-layer fat:  6     Ventral edge fat:  7     Ventral region surface-layer fat:  8     Anal region:  9     Ventral fin:  10     Tail section:  11         

   The machine according to the invention performs five cutting operations; three vertical cuts A, B, and C as identified in  FIGS. 5–9 , and two horizontal cuts D and E that remove surface tissues. 
   Cut A: Dorsal edge cut: A first cutting mechanism  38  having a circular blade  40  as shown in  FIG. 12  removes any remaining portions of the dorsal fin and fat fin that may have been left during the initial filleting process, as well as the dorsal edge fat strip. 
   Cut B: Tail cut: A second cutting mechanism  34 , comprising a knife blade  36 , removes the tail section from the fillet in a chopping motion. 
   Cut C: Ventral edge cut: A third cutting mechanism  42  having a circular blade  40  as shown in  FIG. 14  removes the ventral edge of the fillet, including the ventral fin muscle and anal region, and trims the area behind the anal region. 
   Cut D: Dorsal surface cut: A fourth cutting mechanism  44  having an oscillating blade  46  and a lifting plate  48  as shown in  FIG. 15  removes the dorsal region surface-layer fat. 
   Cut E: Ventral surface cut: A fifth cutting mechanism  50  having an oscillating blade  52  and a lifting means  54  as shown in  FIG. 16  removes the ventral region surface-layer fat. 
   Mode of Operation 
   The machine operator selects the desired cuts to be performed from the machines database via an operator interface panel and filets are transported in to the machine. 
   The fillets are thereafter transported under the image camera  2  by conveyor  20 , where the areas of undesired tissue are identified, the coordinates of these areas are registered and the necessary movement of the cutting mechanisms calculated. 
   After the camera computer has calculated the cuts to be performed, the fillet is transported by second conveyor  22  to a first cutting mechanism  38 . Conveyor  22  is perforated, and a vacuum system applies suction to the fillets, holding them securely to the surface of the conveyor. 
   The horizontal position of cutting mechanism  38  is directed by control unit  32  according to the coordinates obtained from camera  28  and the speed of conveyor  22 . As shown in  FIG. 11 , cutting mechanism  38  is positioned at an angle relative to the direction of conveyor  22 . Cutting mechanism  38  cuts along the fillet&#39;s dorsal edge based upon the signal sent from the computer in camera  28  to control unit  32 . 
   Cutting mechanism  38 , as shown in  FIG. 12 , comprises a footplate  62  that raises the fillet into contact with circular blade  40 . Circular blade  40  is driven by a motor  64 , and is continuously sharpened by a sharpener  66  and cleaned by water jets integrated into a faceplate  68 . The angle of cutting mechanism  38  causes the resulting waste product to lay on the footplate until the cutting mechanism returns to its  0  position, where the waste is then suctioned off by a vacuum apparatus (not shown) and into a hopper  82 . The weight of the waste is calculated and stored in a database by a computer  30 . Any waste tissue that becomes lodged in the blade is removed with the help of a vacuum pump (not shown) connected to a suction nozzle  70 . 
   After the dorsal edge cut is performed, the fillet is moved forward until the tail section is in position at second cutting mechanism  34 , which removes the tail section of the fillet is a chopping motion; As shown in  FIG. 13 , cutting mechanism  34  comprises a rigid blade  36 , actuated by a piston  39 . A sharpening device  37  is further provided. The waste from this third cut is removed by a compressed air nozzle (not shown), which forces the waste tissue into a container  39  where it is thereafter suctioned off into hopper  82 . The weight of the tail is calculated by the computer and stored in the database. 
   The fillet is thereafter transported to third cutting mechanism  42  as shown in  FIG. 14 , which trims the ventral edge in essentially the same manner as the dorsal edge. When cutting mechanism  42  returns to its 0 position, the waste product falls into a container having a weighing means  58 . When a predetermined weight is reached, the wasted is ejected by a compressed air nozzle onto and transported away by a waste conveyor  60 . 
   After the ventral edge trimming, the fillet is transported to fourth cutting mechanism  44 , depicted in  FIG. 15 . Cutting mechanism  44  comprises a horizontally oscillating blade  46 , driven by a motor  74 , that performs a horizontal cut in order to remove a surface layer of fat from the dorsal region. As shown in  FIGS. 3 and 5 , this fat region is lower than the thicker meat section in the dorsal region. The dorsal edge of the fillet must therefore be raised in order to present a flat surface to blade  46 . Cutting mechanism  44  therefore further comprises a slideable, curved lifting plate  48 . Control unit  32  causes lifting plate  48  to be pressed in towards the fillet. The edge of the fillet then rides up the curved surface of the lifting plate until the fillet&#39;s dorsal edge is raised to the same height as the thickest part of the fillet, as previously measured by height-measuring unit  24 . A horizontal guide member  78 , located above the fillet, presses down on the fillet in order to maintain the flat surface is well as to provided resistance when the fillet is cut by blade  46 . At the moment of cutting, a vacuum pump connected to a nozzle  81 , applies suction to the fat layer, drawing the layer of fat away from the fillet. The fat is suctioned away and stored in hopper  82 . Cutting mechanism  44  further comprises water jets that clean blade  46 , as well as a sharpening unit  84 . 
   After the dorsal region surface-layer fat has been removed, the fillet is transported to fifth cutting mechanism  50 , as shown in  FIG. 16 . Cutting mechanism  50  comprises a horizontally oscillating blade  52  driven by a motor  87 . Cutting mechanism  50  performs a horizontal cut that removes the ventral region surface-layer fat. As is the case with the dorsal region, the ventral edge must be raised in order to present a flat surface for cutting. The ventral edge of the fillet is of a slightly different shape than the dorsal edge. Cutting mechanism  50  therefore comprises a lifting plate  54  and a horizontal guide member  88 . The ventral edge of the fillet rides up on plate  54 , and is caused to press upon guise member  88 , thus presenting a horizontal surface for cutting to blade  52 . Cutting mechanism  50  also comprises a vacuum nozzle  90 , integrated water jets  92  and a sharpening unit  94  that perform similar functions as in cutting mechanism  44 . 
   The finished fillet product is then transported to the end of the trimming machine and collected for packaging, etc.