Patent Publication Number: US-2011070815-A1

Title: Indexing drive system

Description:
CROSS REFERENCE TO PRIOR APPLICATIONS 
     This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/244,764, filed Sep. 22, 2009, and titled “Indexing Drive System for Tenderizer,” the disclosure of which is expressly incorporated by reference herein in its entirety. 
    
    
     FIELD OF THE DISCLOSURE 
     The present disclosure relates to an apparatus, a system and a method for driving a device for conditioning food products, such as, for example, meat, poultry, and the like, to improve their texture and improve consumer taste preference for the conditioned product when compared with an equivalent non-conditioned sample. 
     BACKGROUND OF THE DISCLOSURE 
     Mechanical blade tenderizers are commonly used by meat processors to cut through sinew and connective tissue when processing various cuts of meat and poultry. The process of cutting through sinew and connective tissue may increase the desirability of the resultant product, since consumers typically regard the product as more tender and delicious. Generally, when a blade-tenderized product is compared to a similar cut that has not been processed, the tenderized product is generally preferred by consumers by a wide margin (at least a 65% preference). 
     Currently, ratchet linkage assemblies are frequently used to drive mechanical blade tenderizers. These are complex systems with critical timing issues. The systems require the timing to be set or fined tuned with precision and expertise, requiring a high level of mechanical expertise for maintenance or repair. These systems do not typically include overload protection, so if a jam should occur in the tenderizer, one or more components of the tenderizer drive are likely to break, often a rod end or a linkage arm. 
     The present disclosure provides an apparatus, a system and a method for driving an indexing device that conditions or further processes food products (for example, non-intact meat and poultry products), such as, for example, a mechanical blade tenderizer, a cuber, a tender press, or injector, for conditioning food products, which provide increased reliability and reduced complexity. The disclosure also provides higher stroke rates as the motion is completed more quickly during each cycle of operation of the apparatus. 
     SUMMARY OF THE DISCLOSURE 
     According to an aspect of the present disclosure, a driver is disclosed for a food conditioner. The driver comprises: a drive shaft that is configured to be driven by a motor; a continuous-to-intermittent converter that is configured to be coupled to the drive shaft; and a slip dutch that is configured to be coupled to the continuous-to-intermittent converter, wherein the slip clutch is further configured to disengage when a torque applied to the slip clutch exceeds a predetermined threshold. The continuous-to-intermittent converter may comprise a Geneva drive gear, or a Maltese Cross drive gear. The driver continuous-to-intermittent converter may comprise: a master drive gear coupled to the drive shaft; and a slave drive gear that is intermittently coupled to the master drive gear. The master drive gear may include a cam follower and wherein the slave drive gear includes a slot that is configured to receive the cam follower. 
     The slip clutch may comprise: an engager portion that is configured to drive a transporter; and a clutch portion that is configured to disengage the engager portion to cause the engager portion to stop rotation while the drive shaft continues to rotate substantially continuously. The engager portion may comprise a sprocket. 
     The driver may further comprise: a driven shaft coupled to the continuous-to-intermittent converter and the slip clutch, the driven shaft being configured to drive the slip clutch; or a drive unit that is configured to drive a food processor. The drive unit may comprise a lifter. The driver may further comprise a cam unit that is coupled to the drive shaft. 
     According to a further aspect of the disclosure, a driver is disclosed for a food conditioner, wherein the driver comprises: a drive shaft that is configured to be driven by a motor; a master drive gear that is coupled to the drive shaft; a driven shaft that is configured to be driven by a force that is transferred from the master drive gear; and a slip clutch that is coupled to the driven shaft. The master drive gear may include a cam follower. The slip clutch may be configured to disengage when a torque applied to the slip clutch exceeds a predetermined threshold. The slip clutch may comprise: an engager portion that is configured to drive a transporter; and a clutch portion that is configured to disengage the engager portion to cause the engager portion to stop rotation while the drive shaft continues to rotate substantially continuously. 
     The driver may further comprise a slave drive gear that is coupled to the driven shaft. The slave drive gear may be configured to intermittently engage the master drive gear while the master drive gear continues to rotate substantially continuously. The master drive gear may comprise a Geneva drive gear or a Maltese Cross drive gear. The slave drive gear may comprise a slot that is configured to receive a portion of the master drive gear. 
     According to a still further aspect of the disclosure, a driver is disclosed for a food conditioner. The driver comprises: a drive shaft that is configured to be driven by a motor; a Geneva drive gear coupled to the drive shaft, the Geneva drive gear comprising a cam follower; a driven shaft that is configured to drive a transport; a Maltese Cross drive gear coupled to the driven shaft, the Maltese Cross drive gear comprising a slot for receiving and engaging the cam follower; and a slip clutch coupled to the driven shaft, wherein the slip clutch is configured to disengage when a force applied to the slip clutch exceeds a predetermined threshold. 
     According to a still further aspect of the disclosure, a driver may be provided for a food conditioner that includes a servo motor and a timing indicator. The driver may include a main drive, the servo motor, a slip clutch and the timing indicator. The timing indicator may be affixed to a rotating cam of the main drive to trigger servo shaft indexing. 
     Additional features, advantages, and embodiments of the disclosure may be set forth or apparent from consideration of the following attached detailed description and drawings. Moreover, it is to be understood that both the foregoing summary of the disclosure and the following attached detailed description are exemplary and intended to provide further explanation without limiting the scope of the invention as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the disclosure, are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the detailed description serve to explain the principles of the disclosure. No attempt is made to show structural details of the disclosure in more detail than may be necessary for a fundamental understanding of the disclosure and the various ways in which it may be practiced. In the drawings: 
         FIG. 1  shows an example of a food conditioner that is constructed according to the principles of the disclosure; 
         FIG. 2A  shows an example of a food conditioning head that may be included in the food conditioner of  FIG. 1 , according to the principles of the disclosure; 
         FIG. 2B  shows a perspective, bottom view of the food conditioning head of  FIG. 2A ; 
         FIG. 2C  shows a detailed view of an area A noted in  FIG. 2B ; 
         FIG. 2D  shows a perspective view of an example of a blade carrier of the food conditioning head of  FIG. 2A ; 
         FIG. 2E  shows a perspective view of an example of a guide plate of the food conditioning head of  FIG. 2A ; 
         FIG. 3A  shows a detailed, partial x-y plane view of a portion of the food conditioner of  FIG. 1 ; 
         FIG. 3B  shows a detailed, partial z-y plane view of a portion of the food conditioner of  FIG. 1 ; 
         FIG. 4  shows a perspective view of a drive system that may be included in the food conditioner of  FIG. 1 ; 
         FIG. 5  shows a detailed view of a portion of the drive system of  FIG. 4 , constructed according to the principles of the disclosure; 
         FIG. 6  shows an exploded view of the drive system of  FIG. 4 ; 
         FIG. 7  shows an example of a slip clutch assembly that may be included in the drive system of  FIG. 4 , according to the principles of the disclosure; 
         FIG. 8  shows an example of a sprocket (or pulley) assembly that may be included in the food conditioner of  FIG. 1 , according to the principles of the disclosure; 
         FIG. 9  shows a representation of an example of a master drive gear and a complementary slave drive gear that may be included in the drive system of  FIG. 4 , according to principles of the disclosure; 
         FIG. 10  shows four discrete examples of the rotational motion of a master drive gear and a slave drive gear that may be used in the drive system of  FIG. 4 , according to principles of the disclosure; and 
         FIG. 11  shows another example of a master drive gear and a slave drive gear that may be included in the drive system of  FIG. 4 , according to principles of the disclosure. 
     
    
    
     The present disclosure is further described in the detailed description that follows. 
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     The embodiments of the disclosure and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments and examples that are described and/or illustrated in the accompanying drawings, and detailed in the following attached description. It should be noted that the features illustrated in the drawings are not necessarily drawn to scale, and features of one embodiment may be employed with other embodiments as the skilled artisan would recognize, even if not explicitly stated herein. Descriptions of well-known components and processing techniques may be omitted so as to not unnecessarily obscure the embodiments of the disclosure. The examples used herein are intended merely to facilitate an understanding of ways in which the disclosure may be practiced and to further enable those of skill in the art to practice the embodiments of the disclosure. Accordingly, the examples and embodiments herein should not be construed as limiting the scope of the disclosure, which is defined solely by the appended claims and applicable law. Moreover, it is noted that like reference numerals represent similar parts throughout the several views of the drawings. 
     The terms “including”, “comprising” and variations thereof, as used in this disclosure, mean “including, but not limited to”, unless expressly specified otherwise. 
     The terms “a”, “an”, and “the”, as used in this disclosure, means “one or more”, unless expressly specified otherwise. 
     Devices that are in communication with each other need not be in continuous communication with each other, unless expressly specified otherwise. In addition, devices, that are in communication with each other may communicate directly or indirectly through one or more intermediaries. 
     Although process steps, method steps, algorithms, or the like, may be described in a sequential order, such processes, methods and algorithms may be configured to work in alternate orders. In other words, any sequence or order of steps that may be described does not necessarily indicate a requirement that the steps be performed in that order. The steps of the processes, methods or algorithms described herein may be performed in any order practical. Further, some steps may be performed simultaneously. 
     When a single device or article is described herein, it will be readily apparent that more than one device or article may be used in place of a single device or article. Similarly, where more than one device or article is described herein, it will be readily apparent that a single device or article may be used in place of the more than one device or article. The functionality or the features of a device may be alternatively embodied by one or more other devices which are not explicitly described as having such functionality or features. 
       FIG. 1  shows an example of a food conditioner  10 , which is constructed according to the principles of the disclosure. The food conditioner  10  may include, for example, a tenderizer, a cuber, a press, or the like, to process a food product. The food conditioner  10  includes an input transport  20 , a food processor  30 , an output transport  40  and a housing  50 . The food processor  30 , which may include a tenderizer, a cuber, a press, or the like, may be contained in a housing  32  that may include panel doors  35  for access to a processing chamber (not shown) of the food processor  30 . The input transport  20  and output transport  40  may each include, for example, a conveyor belt (not shown). The conveyor belt may include a stainless steel belt, a rubber belt, a plastic belt, or the like, with or without openings. The food processor  30  may include a guard (not shown) on the infeed and discharge sides of the food processor  30 . The guard may include a plurality of unidirectional rods (not shown) that form a curtain (not shown) to prevent, for example, from a human hand being inserted in the food processer  30  during operation. The guard may be coupled to an interlock safety switch (not shown), which may be configured to prevent operation of the food conditioner  10  when any of the guards are dislodged or removed. 
       FIG. 2A  shows an example of a food conditioning head  300  that may be used in the food processer  30  to process food products, according to the principles of the disclosure. The head  300  may include a plurality of blades  310 , a blade carrier  320 , a guide plate  330 , and a plurality of guide rods  340 . Each guide rod  340  may include, for example, a threading (not shown) on both ends and a flange  345  located near the threading at one end. The flange  345  end of each guide rod  340  may be fixedly secured to the guide plate  330  by a fastener  350 . The other, opposite end of each guide rod  340  may be capped by the fastener  350 , which may serve as a stop for limiting the movement of the blade carrier  320  along the guide rods  340 . The fastener  350  may include, for example, a nut, a bolt, a screw, a weld, a rivet, or the like. The blade carrier  320  may include a guide  355  on each of its longitudinal ends for receiving a respective guide rod  340 . The guide  355  may include a bushing, a bearing, or the like, that is configured to provide substantially frictionless linear movement of the guide rod  340  there-thru. The guide rods  340  together with the guides  355  provide free moving alignment of the blade carrier  320  and the guide plate  330  to guide the blades  310  cleanly and smoothly into the food product. 
     The functionality, durability and strength of the food processor  30  is enhanced by the upward and downward movement of the plurality of blades  310  and the head  300  configuration. In this regard, the blade carrier  320  and/or the guide plate  330  may be made from high strength plastic and/or steel. 
     Although the example of the head  300  shown in  FIG. 2A  includes a pair of guide rods  340 , it is noted that the head  300  may include any number of guide rods  340 , such as, for example, three, four, five, six, and the like, but preferably even numbers of guide rods  340 , such as, for example, four, six, eight, and the like. The blade carrier  320  and/or the guide plate  330  may be made from materials such as, for example, a plastic, a metal, or the like, or a combination of the foregoing. The plastic may include a high strength plastic, such as, for example, Ertalyte®, or the like. The metal may include, for example, stainless steel, or the like. The blade carrier  320  and/or the guide plate  330  may be made entirely from stainless steel to minimize the risk of breakage. The blade carrier  320  may include slotted plastic inserts (not shown) for less friction due to the relative motion between the blade carrier  320  and the blades  310 . 
     The blade carrier  320  may include, for example, an upper an upper plate and a lower blade alignment bushing plate (not shown), which may be coupled together by a fastener (not shown), such as, for example, a tongue-and-groove coupling, a screw, a bolt, a nut, a rivet, an adhesive, or the like. 
       FIG. 2B  shows a perspective, bottom view of the head  300 , according to the principles of the disclosure. 
       FIG. 2C  shows a detailed view of an area A noted in  FIG. 2B . As seen in  FIG. 2C , the guide plate  330  includes a plurality of thru-openings  335  for receiving and guiding a respective plurality of the blades  310  there-thru. Each of the plurality of openings  335  may include, for example, a cross pattern. Each blade  310  may have a profile width along two of its sides that is about, for example, three times the width along the other two sides of the blade  310 . The blades  310  may be configured to penetrate directly into the interior of the food product (not shown). For maximum tenderization and cutting of, for example, connective tissue, the blades  310  may be configured in a crisscross pattern, with every other blade  310  being turned about 90° to ensure that sinew is sliced and the processed food product is made more tender. 
     It is noted that other configurations for the blades  310  may be equally used, including width ratios that are substantially greater (or smaller) than about 3:1. It is also noted that the head  300  is not limited to a single guide plate  330 , but may include two or more guide plates  330  for added rigidity of the blades  310  during operation of the food conditioner  10  (shown in  FIG. 1 ). 
       FIG. 2D  shows a perspective view of an example of the blade carrier  320 . The blade carrier  320  may include a plurality of receptacles  325  for receiving and securely holding a respective plurality of blades  310 . The receptacles  325  may be formed in a plurality of longitudinal magnets  322 , or the receptacles  325  maybe formed in a plurality of longitudinal plates sandwiched between the longitudinal magnets  322 . Thus, the blades  310  may be easily affixed and secured to the blade carrier  320 , allowing for easy replacement of any one or more of the plurality of blades  310 . 
     It is noted that if the food products include only bone-less products, then the plurality of blades  310  may be fixed to the blade carrier  320 , instead of being held in place by the longitudinal magnets  322 . 
       FIG. 2E  shows a perspective view of an example of the guide plate  330 , constructed according to the principles of the disclosure. As seen in the figure, the guide plate  330  may include a plurality of cross pattern thru-openings  335  for receiving and guiding a respective plurality of blades  310 . 
       FIG. 3A  shows a detailed, partial x-y plane view of a portion of the food conditioner  10 . The food conditioner  10  may include a motor  210  for driving the input transport  20 , the food processor  30 , and/or the output transport  40 . The food processor  30  may include a plurality of food conditioning heads  300  (shown in  FIG. 2A ), which may be configured to penetrate the food product (not shown) either (or both) vertically (e.g., along y-axis, shown in  FIG. 3A ) or horizontally (e.g., along z-axis, shown in  FIG. 3B ). The motor  210  may be affixed to a chassis  15  of the food conditioner  10 . The motor  210  may include a rotor shaft  215  that may be coupled to a cam unit  217 , which may be coupled to a drive unit  220 . The motor  210  may include, for example, a regulated stepper or servo motor. The cam unit  217  may include a cam (not shown) that is coupled to the shaft  215 . The cam may be configured to engage and drive one or more lifters (not shown) that may be provided in the drive unit  220 , lifting and lowering the one or more lifters as the cam rotates with the rotation of the shaft  215 . The lifters may be coupled to one more food conditioning heads  300 , driving the blades  310  into a food conditioning chamber (not shown) in the food processor  30  and retracting the blades  310  from the food conditioning chamber. The cam unit  217  may be coupled to a drive system  250  through a drive shaft  230  and a motor coupler  240 . 
     The drive system  250  may include a master drive gear  2510  and a force limiting slip clutch assembly (or slip clutch)  265 . The master drive gear  2510  may include, for example, a Geneva drive gear. The drive system  250  may be coupled to the input transporter  20  by means of a belt  260 , a sprocket (or pulley)  270 , a belt  280 , and a sprocket (or pulley)  290 . A plurality of tensioners  262 ,  282  may be provided to apply a respective force to the belts,  260 ,  280  to keep the belts taut. The tensioners  262 ,  282  may include, for example, sprockets, pulleys, wheels, or the like. The sprocket  270  and the plurality of tensioners  262 ,  282  may be assembled in a sprocket (or pulley) assembly  400 . The belts  260 ,  280  may include, for example, a stainless steel belt, a serpentine belt, a Gilmer belt, a chain, a timing belt, a V-belt, or the like. 
       FIG. 3B  shows a detailed, partial z-y plane view of a portion of the food conditioner  10 . The drive system  250  may further include a slave drive gear shaft  2520 , a slave drive gear  2530 , a mount assembly  2540 , a plurality of guides  2545 ,  2550 ,  2555 , a motor coupler  245 , and a gear assembly  500 . The drive (or driven) shaft  2520  is configured to be driven by a force that is transferred from the master drive gear  2510  via the slave drive gear  2530 . The slave drive gear  2530  includes a gear that is configured to engage and be driven by the master drive gear  2510 , which may include a Geneva drive gear. The master drive gear  2510  and the slave drive gear  2530  together makeup a continuous-to-intermittent converter  2510 ,  2530  that converts a continuous rotary motion of the master drive gear  2510  to an intermittent rotary motion of the slave drive gear  2530 , with the drive gear  2530  turning during discrete intervals of time. The guides  2545 ,  2550 ,  2555 , which may include a bearing (such as, for example, a ball bearing), are configured to support and allow the slave drive gear shaft  2520  to rotate without any friction, or with substantially zero friction. 
       FIG. 4  shows a perspective view of the drive system  250 . The drive system  250  may include, for example, a plurality of support members  266 ,  2552 ,  2554 , a shaft  2560 , and a plurality of guides  2570 ,  2575  (shown in  FIG. 6 ). The guide  2570  may be configured substantially the same as (or different) to the guides  2545 ,  2550 ,  2555 . The plurality of support members  266 ,  2552 ,  2554  may be affixed to the chassis  15 . The plurality of support members  266 ,  2552 ,  2554  may include the plurality of guides  2570 ,  2555 ,  2550 ,  2545 . Each of the support members  266 ,  2552 ,  2554  may be configured in the shape of a plate that may be affixed to the chassis  15 . 
       FIG. 5  shows a detailed view of a portion of the drive system  250 , constructed according to the principles of the disclosure. 
       FIG. 6  shows an exploded view of the drive system  250 . As seen, the support member  266  may include an opening  2556  that is configured to receive and securely hold the guide  2555  in place. The guide  2555  is configured to receive one end of the shaft  2520  and to allow the shaft  2520  to rotate without any friction, or with substantially zero friction. 
     The support member  2552  may include a pair of openings  2551 ,  2576  for receiving and securely holding the guides  2550 ,  2575 , respectively. The guide  2550  is configured to receive and support the shaft  2520 , allowing the shaft  2520  to rotate with substantially zero friction. The slip clutch assembly  265  may be mounted to the shaft  2520  and positioned between the support member  266  and the support member  2552 . The guide  2575  is configured to receive and support one end of a shaft  2590 , allowing the shaft  2590  to rotate with substantially zero friction. 
     The support member  2552  may be affixed to the chassis  15  by means of a plurality of fasteners  16 . Each fastener  16  may include, for example, a bolt, a nut, a screw, a weld, a pin, a rivet, or the like, or a combination of the foregoing. 
     The support member  2554  may include a pair of openings  2546 ,  2572  for receiving and securely holding the guides  2545 ,  2570 , respectively. The guide  2545  may be configured to receive and support another end of the shaft  2520 , which is opposite to the end of the shaft  2520  that may be supported by the guide  2555 . The guide  2570  may be configured to receive and support a portion of the shaft  2590 , allowing the end of the shaft  2590  to pass through the guide  2570  and engage the motor coupler  245 , where the end of the shaft  2590  may be coupled to the motor coupler  245 . The guides  2545 ,  2570  are configured to allow the shafts  2520 ,  2590 , respectively, to rotate without any friction, or with substantially zero friction. 
     The support member  2552  may be coupled to the support member  2554  through the mount assembly  2540 . The mount assembly  2540  may include a plurality of fasteners  2542 ,  2543 . The fasteners  2542 ,  2543  may include, for example, a screw and a spacer, respectively. The fastener  2542  may be configured to be substantially the same as, for example, the fasteners  16 . 
     In between the support members  2552  and  2554 , a pair of spacers  2572 ,  2574  may be provided on the shaft  2590  on either side of the master drive gear  2510 . The spacers  2572 ,  2574  may include, for example, bushings, or the like. The shaft  2590  may include a recess (or key)  2592  for engaging a portion of the master drive gear  2510  and preventing the master drive gear  2510  from rotating with respect to the shaft  2590 . The master drive gear  2510  may include a cam follower  2519 , which may be affixed to the master drive gear  2510  by a fastener  2518 . The fastener  2518  may be similar to the fastener  16 . 
     Also in between the support members  2552  and  2554 , a pair of spacers  2534 ,  2536  may be provided on the shaft  2520  on either side of the slave drive gear  2530 . The spacers  2534 ,  2536  may include, for example, bushings, or the like. The shaft  2520  may include one or more recesses (or keys)  2532 ,  2525  for engaging a portion of the slave drive gear  2530  and a portion of the slip clutch assembly  265 , respectively, to prevent the slave drive gear  2530  or the portion of the slip clutch assembly  265  from rotating with respect the shaft  2520 . 
     As seen in  FIG. 6 , the various components of the drive system  250  may be coupled to the chassis  15  by means of a plurality of the fasteners  16 . The chassis  15  may include a base plate  14  and a frame  17 . For example, the gear assembly  500  may be affixed to the base plate  14  by means of the fasteners  16 . A pair of support blocks  19  may be placed between the gear assembly  500  and the base plate  14 . 
       FIG. 7  shows an example of a slip clutch assembly  265 , according to the principles of the disclosure. The slip clutch assembly  265  includes an opening  2652  for receiving and passing there-thru the end portion of the shaft  2520 . The slip clutch assembly  265  further includes a clutch portion  2654  and an engager portion  2656 . The engager portion  2656  may include a sprocket, a pulley, or the like, or a combination of the foregoing. The clutch portion  2654  is configured to engage or disengage the engager portion  2656  to cause the engager portion  2656  to rotate. The clutch portion  2654  may include a spring (not shown), a bushing (not shown), or the like. The slip clutch assembly  265  is configured to limit the transfer of torque from the drive shaft  2520  to the belt  260 , disengaging the engager portion  2656  from the shaft  2520  when the torque on the engager portion  2656  exceeds a predetermined threshold, such as, for example, about 18.7 ft-lbs, but other threshold values may be used, as will be appreciated by one having ordinary skill in the art. For example, the threshold value may be dependent on the materials selected for the various components and the corresponding coefficients of static friction, conveyor belt lengths, the particular food products to be processed, and the like. The particular configuration of the engager portion  2656  should be matched to the configuration of the belt  260  (shown in  FIG. 3A ), which is to be driven by the engager portion  2656 . 
       FIG. 8  shows an example of the sprocket (or pulley) assembly  400 , which is constructed according to the principles of the disclosure. The sprocket assembly  400  includes the sprocket  270  and the plurality of tensioners  262 ,  282 . The sprocket assembly  400  may include a pair of assembly supports  412 ,  414  that may be rigidly spaced apart by a plurality of spacers  415 , which may have substantially the same (or different) lengths, and secured to each other by a plurality of fasteners  416 . The fasteners  416  may be substantially the same as, or similar to the fasteners  16 . 
     The assembly supports  412 ,  414  may include, for example, a pair of plates. In between the assembly supports  412 ,  414 , the sprocket  270 , a sprocket (or pulley)  425  and a plurality of spacers  429  may be mounted to a shaft  428 . The spacers  429  may include, for example, bushings. One end of the shaft  428  may be inserted in and supported by a guide  423 . The other, opposite end of the shaft  428  may be inserted in and supported by a guide  4140 . The guides  423 ,  4140  may be located in the assembly supports  412 ,  414 , respectively. The guides  423 ,  4140  may include, for example, a ball bearing, or the like, to rotationally support the shaft  428 , allowing the shaft  428  to rotate with substantially zero friction. The shaft  428  may include a recess (or key)  424  that is configured to engage a corresponding protrusion (not shown) on the sprockets  270 ,  425 , so as to secure the sprockets  270 ,  425  to the shaft  428  and prevent the sprockets  270 ,  425  from rotating with respect to the shaft  428 . The sprocket  425  may be configured to engage and drive the belt  280  (shown in  FIG. 3A ), while the sprocket  270  engages and receives a driving force from the belt  260  (also shown in  FIG. 3A ). 
     The tensioners  262 ,  282  may be coupled to a pair of idlers  430 ,  440 , respectively. The idler  430  may be coupled between the assembly supports  412 ,  414  by means of spacers  419 ,  435  and a fastener  4191 . The spacer  435  may include, for example, a bushing, and the spacer  419  may include, for example, a threaded stand-off fastener. The idler  440  may be coupled to the assembly support  414 . Each of the idlers  430 ,  440  may further include a spring (not shown) to rotationally bias the position of the idlers  430 ,  440  with respect to the sprocket assembly  400 , so as to provide tension, for example, to the belts  260 ,  280  (shown in  FIG. 3A ), respectively. 
       FIG. 9  shows a representation of an example of the master drive gear  2510  and a complementary slave drive gear  530 , according to principles of the disclosure. The master drive gear  2510  includes the cam follower  2519  and a semi-cylindrical portion  2514 . The slave drive gear  530  includes a plurality of slots  2539 , each of which is configured to receive and engage the cam follower  2519 . As seen in  FIG. 9 , the master drive gear  2510  may include a Geneva drive gear and the slave drive gear  530  (or  2530 ) may include a Maltese Cross drive gear. The slave drive gear  530  may include any number of slots  2539 , including, for example, a single slot, two slots, three slots, four slots (as shown in  FIG. 5 ), five slots, six slots (as shown in  FIG. 9 ), or more. The master drive gear  2510  and the slave drive gear  530  (or  2530 ) are configured to convert a continuous rotation of the master drive gear  2510  to an intermittent rotary motion of the slave drive gear  530  (or  2530 ). 
       FIG. 10  shows four discrete examples of the rotational motion of the master drive gear  2510  and the slave drive gear  2530 , according to principles of the disclosure. The four discrete examples show how the continuous rotational motion of the master drive gear  2510  may be harnessed and used to intermittently drive the slave drive gear  2530 . 
     Referring to  FIG. 10  from left to right, initially the cam follower  2519  reaches the opening of the slot  2539  of the slave drive gear  2530 . The cam follower  2519  proceeds to travel along the length of the slot  2539  as the master driver gear  2510  rotates in, for example, a continuous clockwise direction. Simultaneously the cam follower  2519  engages and presses on a wall of the slot  2539 , thereby causing the slave drive gear  2530  to rotate, for example, in a counter-clockwise direction. The master drive gear  2510  continues to rotate at a substantially constant speed, carrying the cam follower  2519  and driving the slave drive gear  2530  until the master drive gear  2510  and slave drive gear  2530  reach the configuration shown in the rightmost discrete example shown in  FIG. 10 , at which point the cam follower  2519  travels out of the slot  2539  while the slave drive gear  2530  remains stationary until the cam follower  2519  engages the slot  25391 . 
       FIG. 11  shows another example of a master drive gear  610  that may be used in conjunction with another example of a slave drive gear  630 , constructed according to principles of the disclosure. As seen in  FIG. 11 , the master drive gear  610  may include a cam follower  619  that is configured to travel into and engage the walls of one of a plurality of slots  639  provided in (or on) the slave drive gear  630 . 
     It is noted that the master drive gear  610  and the slave drive gear  630  may be replaced with a servo motor (not shown) and a sensor (not shown) to trigger an independent servo motor motion in time with the lifting cam. A servo driver (not shown) may be included to regulate the motion, speed, acceleration and deceleration of rotation of the servo motor. The sensor may be configured to detect, for example, a timing element that may be affixed to the rotating cam. 
     While the disclosure has been described in terms of exemplary embodiments, those skilled in the art will recognize that the disclosure can be practiced with modifications in the spirit and scope of the appended claim, drawings and attachment. The examples provided herein are merely illustrative and are not meant to be an exhaustive list of all possible designs, embodiments, applications or modifications of the disclosure.