Abstract:
A variable speed linking device wherein the rotational speed of the chains is reduced approximately when the outer edge of the pinchers first engage a casing.

Description:
BACKGROUND OF THE INVENTION 
     This invention is directed to a linker for processing food products, and more particularly a linker having a variable rotational speed. 
     Linker devices are well-known in the art. With conventional linkers, as the pinchers rotate about the input end, the outer edge of the pincher rotates at a speed greater than the speed of the base and chain. Because the outer edge engages a casing at an increased speed, the outer edge pulls the casing forward at a speed greater than the base which results in air pockets forming within a filled casing and fracture of the food product. Thus, a device that addresses this deficiency is needed in the art. 
     A principal objective of the present invention is to provide a linking device that has a variable speed. 
     A further objective of the present invention is to provide a linking device that engages a casing at a generally constant speed. 
     These and other objectives will be apparent to one of ordinary skill in the art based upon the following written description, drawings an claims. 
     SUMMARY OF THE INVENTION 
     A linker device having a pair of continuous chains or belts positioned in spaced relation. The chains are mounted to sprockets driven by a servo motor controlled by a computer. Attached to the chains are a plurality of pinchers that are positioned such that the pinchers on one chain align with and intersect with the pinchers on the other chain without making contact. 
     The chains rotate at a transport speed until approximately when the outer edges of aligned pinchers first engage a casing placed over the discharge end of a stuffing tube. The rotational speed of the chains returns to the transport speed approximately when the aligned pinchers intersect to squeeze and compress a filled casing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a linking device; 
         FIG. 2  is a partial side view of a linking device; and 
         FIG. 3  is a partial end view of a linking device. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the Figures, the linker  10  has a pair of chains or belts  12 ,  14  mounted on a plurality of sprockets or pulleys  16 . The sprockets  16  are mounted on rotating shafts  18  which are driven by a servo motor  20  controlled by a computer, PLC, controller  22  or the like. 
     Mounted to the chains  12  and  14  are a plurality of pinchers  24 . The pinchers are positioned on the chains  12  and  14  such that upon rotation of the chains  12  and  14 , the pinchers  24  align to squeeze and constrict a casing  26  filled with meat emulsion at the load end  28  of the linker  10 . The pinchers  24  remain aligned as the filled casings are transported through the linker  10  and between the chains  12  and  14  to the discharge end  30 . 
     The pinchers  24  have a base  32  that is connected to the chains  12  and  14  and extend outwardly to an outer edge  34 . As the pinchers  24  extend outwardly they are angled such that a first side edge  36  dwells to the left of the plane  38  extending outwardly from the base  32  and the second side edge  40  dwells to the right of the plane  30 . The outer edge  34  has a generally centrally located recess  42 . The angle of the pinchers  24  on chain  12  are opposite the angle of pinchers  24  on chain  14  and are spaced from one another such that they intersect at the recess  42  without making contact. 
     In operation the controller  22  sends a signal to the servo motor  20  which controls the rotation of drive shaft  18 . The drive shafts  18  rotate drive sprockets  16  which in turn rotate chains  12  and  14 . The rotational speed of the chains  12  and  14  is based upon desired pieces of food product per minute. 
     As the pinchers  24  rotate about the load end  28  of the linker  10 , approximately at the position where the outer edges  34  of aligned pinchers  24  first engages a casing  26  as it is being filled on a stuffing tube  44 , the controller  22  sends a signal to the servo motor  20  which slows the rotational speed of chains  12  and  14 . Preferably, the rotational speed of the chains  12  and  14  such that the rotational speed of the outer edges  34 , which have accelerated as they rotate about the load end  28  of the pincher, are decreased to approximately the beginning or transport speed of the chains. To achieve the decrease, the chains  12  and  14  may be stopped or reversed for a micro-second. As the pinchers  24  approach and/or intersect to squeeze and constrict the filled casing  26 , the controller  22  sends a signal to the servo motor  20  to return the rotational speed of the chains  12  and  14  to their beginning or transport speed. In this manner, while the speed of the chains  12  and  14  is briefly decreased, the casing  26  experiences little if any change in speed which reduces the chance of the filled casing having air pockets and fracturing. 
     Thus, a linking device has been disclosed that, at the very least meets all the stated objectives.