Abstract:
A sheet interleaver is provided for a slicing machine that includes a slicing plane for slicing an elongated food product and a sheet from web material beneath the elongated product. The interleaver includes a supply of web material, a drawing station, a feed station, and a controller. The drawing station has a first driver for drawing web material from the supply. The feed station has a second driver for receiving web material from the drawing station and driving the web material through a cutting nip into the slicing plane. The controller is in signal-communication with at least one of the first and second drivers to drive web material at select differential speeds by the first and second drivers such that tension between the drawing station and the feed station is controlled to allow a slackened length of web material between the drawing station and the feed station.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Section 371 National Stage Application, which claims the benefit of priority from PCT International Application No. PCT/US2006/041616, filed Oct. 25, 2006, which claims the benefit of priority from Provisional Application Ser. No. 60/730,304, filed Oct. 26, 2005 and from Provisional Application Ser. No. 60/729,958 filed Oct. 25, 2005, all of which applications are incorporated by reference herein in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Food loaves come in a variety of shapes (round, square, rectangular, oval, etc.), cross-sections, and lengths. Such loaves are made from various comestibles, such as meat, cheese, etc. Most loaves are provided to an intermediate processor who slices and packages the products in groups for retail. 
     A variety of machines have been developed to slice such loaves. Such machines include the FX180™ or the FX Plus™ slicing machines available from Formax, Inc., of Mokena, Ill., USA. The FX180™ and the FX Plus™ machines are high speed food loaf slicing machines that slice one, two, or more food loaves simultaneously using one cyclically driven slicing blade. Independent loaf feed drives are provided so that slices cut from one loaf may vary in thickness from slices cut from the other loaf. The machines include a slicing station that is enclosed by a housing, except for a limited slicing opening. The slicing blade is disposed in the slicing station and a drive rotates the slicing blade at a predetermined cyclical rate on a cutting path through a slicing range that intersects the food loaves as they are fed into the slicing station. 
     In the foregoing machines, the food loaf slices are received in groups of predetermined weight on a receiving conveyor that is disposed adjacent the slicing blade. The receiving conveyor receives the slices as they are cut by the slicing blade. In many instances, neatly aligned stacked groups are preferred and, as such, the sliced product is stacked on the receiving conveyor before being transferred from the machine. In other instances, the groups are shingled so that a purchaser can see a part of every slice through a transparent package. In these other instances, conveyor belts of the receiving conveyor are gradually moved during the slicing process to separate the slices. 
     Paper interleaving mechanisms used in conjunction with cutting machines are disclosed in U.S. Pat. Nos. 6,752,056 and 4,583,435. According to these patents, slabs of product such as cheese are oriented angularly with respect to a horizontal conveyor and are fed downwardly into a slicing plane defined by a moving slicing blade. A roll of web material such as paper is arranged beneath the slab and has a length of web continuously fed toward and beneath a cut face of the slab such that when the cutting blade slices a slice from the slab the cutting blade simultaneously slices off a leading end portion of the web, forming a sheet. The sheet with the overlying slice fall to the conveyor or onto a previously cut slice already deposited onto the conveyor to form a stack. The web is continuously fed such that successive sheets are interleaved with successive cut slices. 
     Both of these patents described the use of air jets to assist in coupling the lead end portion of the web to the front face of the slice to be cut. Both of the patents incorporate driven rollers to dispense the web from a roll of web material. 
     The present inventors have recognized that it would be desirable to improve the reliability of the placement of sheets for interleaving with product slices, particularly for high-speed slicing operations. 
     SUMMARY OF THE INVENTION 
     The present invention provides an improved web dispensing arrangement for interleaving sheets with sliced food product. The invention pertains to high-speed slicing machines wherein web material is dispensed in synchronism with the slicing operation and the leading end portion of the web material is arranged on a downstream side of the cut face of the product and the remaining portion of the web material is arranged on an opposite side of the cutting plane than the leading end portion such that the slicing blade slices not only the product but the leading end portion of the web material. The cut leading end portion of the web material forms a sheet that fronts the cut slice and both fall to a conveyor or onto a stack previously deposited on the conveyor. Thus a stack of interleaved slices and sheets can be formed and conveyed away for packaging. 
     According to one aspect of the invention, a sheet interleaver is provided for a slicing machine that includes a slicing plane for slicing an elongated food product and a sheet from web material beneath the elongated product. The interleaver includes a supply of web material, a drawing station, a feed station, and a controller. The drawing station has a first driver for drawing web material from the supply. The feed station has a second driver for receiving web material from the drawing station and driving the web material through a cutting nip into the slicing plane. The controller is in signal-communication with at least one of the first and second drivers to drive web material at select differential speeds by the first and second drivers such that tension between the drawing station and the feed station is controlled. 
     Preferably, the tension is controlled by the controller to allow a slackened length of web material between the drawing station and the feed station that is greater than a straight line distance of the web material spanning between the drawing station and the feed station. 
     As a further aspect of the invention, a tensioning station is provided between the supply of web material and the drawing station such that tension of the web material between the drawing station and the supply is controlled. 
     As a further aspect of the invention, a sensor is provided that senses the slackened length of web material between the drawing station and the feed station and is in signal-communication with the controller to adjust the differential speed of the first and second drivers to maintain the slackened length at a pre-selected amount. 
     As a further aspect of the invention a pressurized air dispenser is provided that is configured to direct an air stream onto a side of the slackened length to maintain a tension on the slackened length of web material. 
     As a further aspect of the invention, the second driver comprises opposing rollers wherein at least one of the rollers is motor driven and the rollers are pressed together with a resilient interface and roll in opposite directions to form a pinch nip for receiving and driving the web material. 
     Preferably, the resilient interface is discontinuous along a lateral direction of the pinch nip, wherein one of the opposing rollers comprises annular recesses spaced apart along the lateral direction and a respective other of the opposing rollers has a smooth annular surface. A comb plate is provided having a base portion fixed in close proximity to the pinch nip. The comb plate has finger portions that fit into the recesses, the comb plate configured to prevent the web material from wrapping around the one roller. Also, a bottom deflecting surface can be provided. The bottom deflecting surface fixed in position in close proximity to the pinch nip and having a portion that partially curves around the other roller, the deflecting surface plate configured to prevent the web material from wrapping around the other roller. 
     According to another aspect of the invention, a web dispensing apparatus is arranged on a slicing machine having a drive roller and a pinch roller with the web material fed therebetween. The drive roller and the pinch roller rotate in opposite directions to drive an extended end portion of the web material through a cutting nip. The lower frame member rotatably mounts one of the drive roller and pinch roller. An upper frame member mounts the other of the drive roller and pinch roller. The lower frame member is pivotally mounted to the upper frame member. The cuffing nip includes a lower edge of the plastic loaf guide mounted to the upper frame member and a plastic cutting edge mounted to the lower frame member. Pivoting the lower frame member away from the upper frame member opens the cutting nip and the space between the drive and pinch rollers to allow the web material to be threaded between the drive and pinch rollers and through the cutting nip. 
     The drive roller is driven by a servomotor. The servomotor drives the web material in a closely controlled and precise manner. The servomotor can be controlled to interleave a sheet between every cut slice or only interleave sheets between some cut slices but not others, such as between every other cut slice. Alternatively, the servomotor can be controlled to interleave a sheet between every cut slice for a number of slices and then change to interleave sheets less frequently, such as allowing a group of slices to be accumulated without sheets and then interleaving the next group of slices with sheets. The servomotor and associated control allows a great flexibility on the pre-programmed selection of interleaving slices without manual intervention. 
     According to another aspect of the invention, the web material is dispensed by opposing rollers that not only drive the end portion through the cutting plane but also bend the end portion into a corrugated cross-section. The corrugated cross-section stiffens the web material to project forwardly in cantilever fashion, from the drive rollers without drooping. The corrugated cross-section increases the beam strength of the cantilevered end portion of the web material. 
     The end portion projects from the corrugated cross-section through the cutting nip and is substantially flattened in the cutting nip. It is advantageous that the corrugation not be present outside the cutting nip to a significant degree if an undulating cut edge of the end portion is not desired. 
     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 
         FIG. 1  a perspective view of a high-speed slicing apparatus incorporating the sheet interleaving mechanism of the present invention; 
         FIG. 2  is a diagrammatic sectional view of the slicing apparatus of  FIG. 1 ; 
         FIG. 3  is a fragmentary sectional view taken generally along line  3 - 3  of  FIG. 2 ; 
         FIG. 4  is a fragmentary side view taken along line  4 - 4  of  FIG. 3 ; 
         FIG. 5  is a fragmentary side view taken along line  5 - 5  of  FIG. 3 ; 
         FIG. 6  is a fragmentary, enlarged view taken from figure three; 
         FIG. 7  is a fragmentary perspective view of the interleaving mechanism of  FIG. 2  shown in an operating condition; 
         FIG. 8  is a fragmentary perspective view of the interleaving mechanism of  FIG. 7  shown in an open, refill condition; 
         FIG. 9  is a fragmentary, enlarged elevational view of a portion of the interleaving mechanism shown in  FIG. 2 ; 
         FIG. 10  is a rear elevational view of the portion shown in  FIG. 9 ; 
         FIG. 11  is a right side view of the portion shown in  FIG. 9  taken generally along line  11 - 11  of  FIG. 9 ; 
         FIG. 12  is a sectional view taken generally along line  12 - 12  of  FIG. 9 ; 
         FIG. 13  is a sectional view taken generally along line  13 - 13  of  FIG. 9 ; 
         FIG. 14  is a left side view of the portion shown in  FIG. 9  taken generally along line  14 - 14  of  FIG. 9 ; 
         FIG. 15  is a fragmentary sectional view taken generally along line  12 - 12  of  FIG. 9  with portions removed for clarity; 
         FIG. 16  is a schematic control diagram; 
         FIG. 17  is a schematic, fragmentary sectional view taken generally along line  17 - 17  of  FIG. 4 ; 
         FIG. 18  is a diagrammatic sectional view of the slicing apparatus of  FIG. 1  incorporating an alternate embodiment sheet interleaving mechanism of the invention; 
         FIG. 19  is an enlarged diagrammatic sectional view of a tension controlling station of the sheet interleaving mechanism of  FIG. 18 ; 
         FIG. 19A  is a schematic diagram of a spool tension control system of the invention; 
         FIG. 20  is an enlarged diagrammatic sectional view of an unwinding station of the sheet interleaving mechanism of  FIG. 18 ; 
         FIG. 21  is a fragmentary enlarged view of a feed station of the sheet interleaving mechanism of  FIG. 18 ; 
         FIG. 22  is a further enlarged view of the feed station of the sheet interleaving mechanism of  FIG. 21 ; 
         FIG. 23  is a sectional view taken generally along line  23 - 23  of  FIG. 22 ; 
         FIG. 23A  is a sectional view taken generally along line  23 A- 23 A of  FIG. 23 ; 
         FIG. 24  is a sectional view taken generally along line  24 - 24  of  FIG. 23 ; 
         FIG. 25  is a top view of  FIG. 23 ; 
         FIG. 26  is a sectional view similar to  FIG. 22  but showing the feed station of  FIG. 22  in an open configuration; 
         FIG. 27  is a view taken generally along line  27 - 27  of  FIG. 26 ; and 
         FIG. 28  is a sectional view taken generally along line  28 - 28  of  FIG. 27 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     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. 
       FIG. 1  illustrates one embodiment of a food loaf slicing machine  50  that may incorporate the sheet interleaver of the present invention. The slicing machine can be a high speed slicing machine such as disclosed in U.S. Pat. Nos. 6,484,615; 5,628,237; 5,649,463; 5,704,265; 5,724,874; herein incorporated by reference, or as commercially available as a FX180™, FXPlus™ or SNS® slicing machine and/or system available from Formax, Inc. of Mokena, Ill., USA. 
     Slicing machine  50  comprises a base  51  that is mounted upon four fixed pedestals or feet  52  (three of the feet  52  appear in  FIG. 1 ) and has a housing or enclosure  53  surmounted by a top  58 . Base  51  typically affords an enclosure for a computer  54 , a low voltage supply  55 , a high voltage supply  56 , and a scale mechanism  57 . Base enclosure  53  may also include a pneumatic supply or a hydraulic supply, or both (not shown). 
     The slicing machine  50  may include a conveyor drive  61  utilized to drive an output conveyor/classifier system  64 . 
     The slicing machine  50  of the illustrated embodiment further includes a computer display touch screen  69  in a cabinet  67  that is pivotally mounted on and supported by a support  68 . Support  68  is affixed to and projects outwardly from a member  74  that constitutes a front part of the housing of slicing station  66 . 
     The upper right-hand portion of slicing machine  50 , as seen in  FIG. 1 , comprises a loaf feed mechanism  75  which, in machine  50 , includes a manual feed from the right-hand (far) side of the machine and an automated feed from the left-hand (near) side of the machine. Loaf feed mechanism  75  has an enclosure that includes a far-side manual loaf loading door  79  and a near-side automatic loaf loading door  78 . 
     Referring first to conveyor/classifier system  64  at the left-hand (output) end of slicing machine  50  as illustrated in  FIG. 2 , it is seen that system  64  includes an inner stacking or receiving conveyor  130  located immediately below slicing station  66 . Conveyor  130  is sometimes called a “jump” conveyor. From conveyor  130  groups of food loaf slices, stacked or shingled, are transferred to a decelerating conveyor  131  and then to a weighing or scale conveyor  132 . From the scale conveyor  132  groups of food loaf slices move on to an outer classifier conveyor  134 . On the far side of slicing machine  50  the sequence is substantially the same. 
     Slicing machine  50  may further include a vertically movable stacking grid comprising a plurality of stack members joined together and interleaved one-for-one with the moving elements of the inner stack/receive conveyor  130 . Stacking grid can be lowered and raised by a stack lift mechanism. Alternatively, food loaf slices may be grouped in shingled or in stacked relationship directly on the receive/stack conveyor  130 , with a series of stacking pins replacing the grid. When this alternative is employed, lift mechanism is preferably connected directly to and is used for vertical positioning of conveyor  130 . 
     Loaf feeding mechanism  75  preferably includes a back-clamp  205  respectively associated with each food loaf. The back-clamps  205  secure the rear portion of each loaf and assist in advancing each loaf at individually determined rates into the slicing station  66 . The loaf feeding mechanism  75  also preferably comprises a system of short conveyors for advancing food loaves from loaf feed mechanism  75  into slicing station.  FIG. 2  shows a short lower loaf feed conveyor  163 . The short lower conveyor  163  is located immediately below a short upper feed conveyor  165 . A loaf cutting guide  166  ( FIG. 3 ) is disposed adjacent the conveyors  163 ,  165  with a recess  167  for guiding the loaf to the blade. 
     The slicing machine  50  of  FIG. 1  is shown in a state ready for operation. There is a food loaf  91  on tray  85 ; waiting to be loaded into loaf feed mechanism  75  on the near-side of machine  50 . Machine  50  produces a series of stacks  92  of food loaf slices that are fed outwardly of the machine, in the direction of the arrow A, by conveyor classifier system  64 . Machine  50  also produces a series of stacks  93  of food loaf slices that move outwardly of the machine on its output conveyor system  64  in the direction of arrow A. 
     The loaf feed mechanism  75  drives the loaves into the slicing station where they are sliced by a rotating knife blade  100  ( FIG. 2 ) that is disposed at the output portions of the short conveyors. The thickness and total weight of the slices are controlled by computer  54  which actuates various mechanical components associated with the slicing operation. The slice thickness and total weight for each sliced group are programmed through the touch screen  67  which interfaces with computer  54 . As the blade slices the loaves, the slices are deposited on receiving conveyor  130  where the proper numbers of slices are either stacked or shingled. The receiving conveyor  130  then drives the groups from the slicing station for subsequent classifying and packaging. 
     The drive motor for the blade in slicing station  66  is preferably a D.C. variable speed servo motor mounted in the machine base  51 . The receiver lift mechanism is driven by a stacker lift motor, again preferably a variable speed D.C. servo motor. The loaf feed drive mechanism comprising the back-clamp  205  and the short loaf feed conveyors  163  and  165  is driven by a servo motor. 
       FIG. 2  illustrates the sheet interleave apparatus  300  of the present invention. For purposes of description, a single sheet interleaving apparatus is described for a slicing machine set up for slicing only one loaf. It should be understood that for a slicing machine that slices two or more side-by-side loaves, multiple sheet interleaving apparatuses  300  can be provided in a corresponding side-by-side arrangement. 
     The apparatus  300  includes a web material supply  301  such as a spool  306  for dispensing web material  312  from a roll  308 . The spool  306  is supported on a column  310  that allows the roll  308  to revolve to dispense web material  312 . The web material  312  extends from the roll  308  and is threaded through a web material drawing station such as an unwind station  316 . The web material extends from the unwind station  316  into a feed station  330 . The unwind station  316  is described in detail below. 
       FIGS. 3-8  illustrate the feed station  330  in more detail. The feed station  330  includes an idle roller  336  that deflects the web material  312  upwardly to be threaded through a roller drive that comprises a drive roller  342  and an opposing pinch roller  346 . The drive roller  342  is rotatably mounted at a first end thereof to a first support plate  352  and at a second end to a second support plate  354 . The support plates  352 ,  354  are fixedly attached to the framework of the slicing machine. The support plate  352  extends downward to form a motor support portion  355  that mounts a servomotor or stepper motor  360 . The pinch roller  346  is rotatably mounted at a first end thereof to a first inside support plate  362  and at a second end to a second inside support plate  364 . The inside support plates  362 ,  364  are spaced apart by a pinch roller axle  366 , a bridge plate  367  and a strut  368 . The strut  368  also acts as a pivot for the inside support plates  362 ,  364 . The inside support plates  362 ,  364  can be pivoted on the strut  368  to swing the pinch roller  346  from a working position ( FIG. 7 ) to an open, web material refill or maintenance position ( FIG. 8 ). A plastic cutting guide  370  is mounted to the bridge plate  367  beneath the pinch roller  346  and extends in an angular upward direction, when in the working position, from the inside support plates  362 ,  364 . The plastic cutting guide  370  forms a cutting nip with the loaf guide  166 . 
     The servo motor  360  includes a housing  420  that is fastened to the motor support portion  355 . A motor output shaft is coupled to a drive pulley  424  ( FIGS. 3 and 4 ). The drive roller  342  includes a driven pulley  428 . A drive belt  432  is wrapped around the pulleys  424 ,  428 . Thus the motor  360  when energized drives the drive roller to rotate. A belt tensioner  438  presses an outside surface of the belt  432  to maintain a proper tension of the belt on the pulleys. 
       FIGS. 4 and 17  illustrate a pressurized air manifold  439  that direct a plurality of air streams in the direction F toward the blade  100 . The manifold includes a tubular body  439   b  with an air inlet  439   a . The tubular body is closed at opposite ends and includes a series of orifice outlets  439   c , such as ten, which direct the air in the direction F. 
     As illustrated in  FIG. 6 , the drive roller  342  includes a plurality of circumferential grooves or annular recesses  442  spaced apart by rings  443  along a length of the drive roller  342 . The pinch roller includes a plurality of circumferential shoulders or rings  448  that correspond in axial position to the grooves  442 . On a select group of the shoulders  448 , rubber drive rings  452  are applied, tightly gripping the outside surface of the respective shoulders  448 . When the inside support plates  362 ,  364  are swung upward into working position, the shoulders  448  nest into the grooves  442 . The rubber drive rings  452  approach the radial bottom of the grooves to a close tolerance corresponding to a thickness of the web material  312 . 
     The web material  312  is pinched and bent to be forced into the grooves  442  and over and around the drive rings  452 . The web material  312  is bent into a corrugated shape in the region of the grooves  442 . This corrugated shape flattens out along a length of an extended end portion  312   a  in a forward direction as the extended end portion  312   a  exits a cutting nip  455  formed between a top edge  370   a  of the cutting guide  370  and a bottom edge  166   a  of the loaf guide  166  but is present sufficiently to provide an increased bending moment of inertia or beam strength to the extended end portion  312   a  that extends unsupported from the cutting nip  455 . This additional beam strength prevents the extended end portion  312   a  from drooping before the cut slice falls with the sheet cut from the extended end portion  312   a  onto the conveyor or onto a previously cut slice. 
     The support plates  352 ,  354  are fixedly attached to machine brackets  453 ,  454  respectively via plastic spacers  456 ,  458  and an axle of the idle roller  336  between the plates  352 ,  354 . The guide  166  is also fastened to and between the machine brackets  452 ,  454 . 
     In operation, the web material  312  is driven forwardly by the drive roller  342  to a position where the extended end portion  312   a  of the web material having a length approximately equal to a height of the sliced product loaf or slab  470 . The air from the orifices  439   c  of the manifold  439  assist in holding the extended end portion  312   a  adjacent to the end of the loaf. The blade  100  slices through both the loaf  470  and the extended end portion  312   a  and a sheet formed of the extended end portion  312   a  and a slice  472  fall together onto the conveyor  130 , the sheet underlying the slice. The process is repeated for the next slice resulting in an interleaved stacking of sheets and slices. 
       FIGS. 9-15  illustrate the unwind station  316  for unwinding web material  312  from the roll  308 . The web material  312  is pinched between a drive roller  502  and a pinch roller  504 . The drive roller  502  is driven by a servomotor or stepper motor  506 . The servomotor  506  has an output shaft that rotates a drive pulley  510  that circulates a belt  512  that rotates a driven pulley  514  connected to the drive roller  502  ( FIG. 12 ). The drive roller  502  is mounted by bearings  516 ,  518  between a front sidewall  520  and a rear sidewall  524 . The servomotor  506  is also mounted to the rear sidewall  524 . The sidewalls  520 ,  524  are fastened to a top base of the machine cabinetry. 
     The pinch roller  504  is mounted by bearings  530 ,  532  ( FIG. 13 ) to a front L-shaped lever  536  and a rear plate  538 . The lever  536  and the rear plate  538  are arranged substantially in parallel and connected to each other by a first strut  540  and a second strut  544 . The second strut  544  also rotationally connects the lever  536  and a rear plate  538  to the sidewalls  520 ,  524  via bearings  550 ,  552  ( FIG. 11 ). 
     A pneumatic cylinder  560  is pivotally fastened to the front sidewall  520  by a fastener  562 . The pneumatic cylinder  560  includes a cylinder body  566  that has pressurized air inlet/outlets  570 ,  572  wherein pressurized air is selectively communicated to/from these inlets/outlets to move a piston (not shown) that acts on a actuator rod  576  extending from the cylinder body  566 . The actuator rod  576  is pivotally connected to a substantially vertical leg  536   a  of the L-shaped lever  536  at a pivot connection  577 . Pressurized air within the cylinder  560  can exert an extending force on the actuator rod  576  that will urge the lever  536  clockwise ( FIG. 9 ) about the strut  544  to cause in the pinch roller  504  to exert a clamping force on the web material  312  against the drive roller  502 . Given typical surrounding parameters, the pressure can be about 30 psig. The drive roller  502  includes an outer sleeve  502   a  and the pinch roller  504  includes an outer sleeve  504   a , wherein the outer sleeves  502   a ,  504   a  are composed of a gripping material to effectively, frictionally, transport the web material  312  that is pinched therebetween. 
     The front wall  520  and the rear wall  524  are further braced by a plurality of struts  580 ,  582 ,  584 . 
     A typical configuration of a strut and strut connection of the station  316  is shown in  FIG. 13 , demonstrated by the strut  584 . A typical strut includes a tubular body  588  that has an outside diameter greater than a hole  590  formed in each of the sidewalls  520 ,  524 . The tubular body  588  includes tapped end holes  592 . Fasteners  594  insert through the holes  590  and are threaded tightly into the end holes  592 . The tubular body  588  is thus clamped tightly to an inside surface of the sidewalls  520 ,  524 . 
     In operation, the servomotor  506  is a motor sized to unwind the roll  308  at a sufficient speed, such as a 20-500 RPM, 7.9 lb-in. motor. The servomotor  360  is sized to deliver the extended end portion  312   a  at a rapid rate for the succession of slices. 
       FIG. 16  illustrates in schematic form three degrees of slackness of the web material  312 , shown represented by the line or curves  312   b ,  312   c  and  312   d . Without a sufficient slackness in the web material  312  upstream of the roller  342 , the delivery of the extended end portion  312   a  can be hampered during high speed operation. Additionally, too much slackness can hamper the delivery of the extended end portion  312   a . The line  312   b  representing zero accumulation, and the parabola  312   c  representing maximum accumulation, represent the desired limits of operation. The intermediate parabola  312   d  represents a preferred operating condition. 
     A sensor  600  is used to sense the slackness, or accumulation, of the web material  312  between the rollers  342  and  502 . The sensor can be an ultrasonic sensor, an optical sensor, such as a laser or photoeye, or other type of sensor. The sensor  600  can project an ultrasonic or optical beam signal upwardly. The sensor  600  communicates the web material lowest position, for example the lowest positions on the line or curves  312   b ,  312   c  or  312   d  with the machine control or computer  54  which is in signal-communication with the servomotors  360 ,  506 . If the slackness approaches the condition  312   b , the motor  506  can be increased in speed to unwind material at a greater rate. If the slackness condition approaches condition  312   c  the motor  506  can be slowed. The speed of the motor  360  could also be adjusted in coordination with the slicing speed, if desired, to adjust the slackness. 
       FIG. 18  illustrates an alternate embodiment sheet interleave apparatus  600  of the present invention. This embodiment is identical to the sheet interleave apparatus  300  except as noted. Identical reference numbers indicate like components. 
     The apparatus  600  includes a modified web material supply  601  that includes the spool  306  for dispensing web material  312  from a roll  308 . The spool  306  is supported on a bracket  602  that allows the roll  308  to revolve to dispense web material  312 . A non-contact sensor  604 , such as an ultrasonic or optical sensor senses the diameter of the roll  308  and communicates to machine control or to an alarm when the roll is depleted. 
     The spool  306  is fixed to a disc  605  to rotate therewith. A disc brake assembly  606  is fixed to the bracket  602  and is selectively engageable to the disc  605  to stop the disc  605  and spool  306  from rotating as described below. 
     The web material  312  extends from the roll  308  and is threaded through a tension control station  610  and then to a draw station such as an unwind station  616 . The web material  312  extends from the unwind station  616  into a feed station  630 . The unwind station  616  is described in detail below. 
       FIG. 19  illustrates the tension control station  610  in more detail. The station  610  includes a housing or frame  611 . The web material  312  is first threaded around a first fixed lower idle roller  632  and is then directed upward to wrap around a first upper fixed idle roller  634 . The web material  312  is then directed downward to wrap a dancer roller  636  and then directed upward to wrap a second upper fixed idle roller  638 . The web material  312  is then directed downward to wrap a second lower fixed idle roller  640  and then directed substantially horizontally out of the station  610 . The dancer roller  636  is mounted on a lever  642  that can be pivoted about a pivot attachment  646  to the frame  611  of the station  610 . A lever arm  656  is clamped and pinned to the lever  642  to rotate therewith. The lever arm  656  includes a tail portion  657  below the attachment  646 . The rollers  632 ,  634 ,  638 , and  640  are all rotatably attached to the frame  611 . 
     The lever arm  656  is rotatably attached at connection  660  to an extendable rod  662  of a pneumatic actuator  664 . The pneumatic actuator  664  includes a cylinder  666  that is pinned at connection  667  to the frame  611 . Controlled pneumatic pressure delivered into the cylinder  666  extends or retracts the rod  662 . Pressurized air is pneumatically connected by a circuit to the cylinder  666 . The circuit includes a pressure compensating pressure regulator  669  (shown schematically) delivering pressurized air into an inlet  671  to maintain a consistent pressure in the pneumatic cylinder  666  regardless of the travel of the rod  662 . The air pressure within the cylinder  666  urges the rod  662  to the right in the figure. Given typical surrounding parameters, this pressure can be about 12 psig. This consistent force on the arm  656  creates a consistent tension in the web material  312  by the downward force from the dancer roller  636  on the web material  312  caused by torque on the arm/lever assembly  656 ,  642  from the actuator  664 . End-of-travel shock absorbers  680 ,  682  are contacted and engaged by extreme positions of the lever arm  656  or the tail portion  657 . These shock absorbers  680 ,  682  cushion the end of travel of the arm  656  and tail portion  657  resulting in better tension control. Two extreme positions of the components  662 ,  656 ,  657 ,  642 ,  636  are shown. An intermediate, normal position of the components  642 ,  636  is also shown. 
     Additionally, grounding tabs  688  are applied to the idle rollers to eliminate any static buildup produced during the feeding of the web material  312  over metal rollers. Static buildup can have a negative effect on any solid-state machine controls. 
     A manually activated valve  670  is provided within the frame  611 . This valve includes a switch arm or lever  671  that is located to be triggered when the lever arm  656  reaches close to its extreme clockwise rotation, when the rod  662  is drawn to an extreme position to the right, fully retracted into the cylinder  666 , and the dancer roller  636  is located at a low position. The valve  670  is pneumatically connected to a source of pressurized air and to the disc brake assembly  606  of the web material supply  601  as shown in  FIG. 19A . 
       FIG. 19A  illustrates a spool control circuit  672 . The valve  670  of the tensioning station is connected to a supply of pressurized air. Preferably, a pressure regulator  673  delivers pressurized air into the valve  670 . The valve  670  is configured to be normally closed, such as by a spring, blocking air flow through the valve  670 . The disc brake assembly  606  of the web material supply  601  includes opposing brake pads  674   a ,  674   b  that are carried by a housing  675 . The pad  674   b  is movable toward and away from the disc  605  by a pneumatic cylinder actuator  676 . The outlet of the valve  670  is pneumatically connected to the actuator  676 . When the lever arm  656  pushes the lever or switch arm  671  the valve  670  is opened, and the actuator  676  receives pressurized air from the valve  670 . The force of the pressurized air within the actuator  676  causes the pad  674   b  to overcome the urging of a spring  677  that urges the pad  674   b  away from the disc  605 , to clamp the pads  674   a ,  674   b  onto the disc  605  to stop spinning of the spool. The dancer roller  636  will begin to rise from tension force from the web material  312  and the lever arm  656  will disengage the switch arm or lever  671  which will close the valve  670 . The spring  677  will move the pad  674   b  away from the disc  605  and the disc  605  will be free to spin and dispense more web material  312 . The dancer roller  636  will begin to fall until the lever arm  656  once again opens the valve  670  and the process repeats. 
     The valve  670  can be a solenoid electric/pneumatic type valve wherein the switch arm  671  is an electrical switch, or it can be a pneumatic valve wherein the lever  671  is a mechanical valve actuator. 
     Although the described control system provides for an oscillating movement of the dancer roller  636  and an oscillating engagement of the brake  606 , it is encompassed by the invention that a set-point type control of the dancer roller position could be employed wherein the braking force on the disc is substantially continuous but modulated in force or duration to keep the dancer roller  636  at a desired position or within a desired range of positions. 
       FIG. 20  illustrates the web material draw station or unwind station  616 . The unwind station  616  includes modifications to the previously described unwind station  316 . Particularly, the web material  312  entering the unwind station is wrapped around an upper fixed idle roller  690  and then a lower fixed idle roller  692  which are mounted to a station frame  700 . After the lower fixed idle roller  692 , the web material  312  is wrapped around the driven roller  502 . By the use of the two idle rollers  690 ,  692 , the web material  312  can be wrapped around the driven roller  502  to a greater extent for more traction and control. 
     Also, a bracket  706  is mounted to the lever  536  and extends to a clamp arrangement  708 . An air dispensing tube  710  is mounted to the bracket  706  and is configured to have orifices to dispense pressurized air in one or more streams  712  directed downward into the web material  312  that is located between the unwind station  616  and the feed station  630 . Impingement or pressure from the streams  712  causes a slight tension in the slackened web material  312  to enhance the controllability and functionality of the sensor  600 . The slight tension results in a uniform tension of the web material  312  to the feed station  630 . 
     Additionally, grounding tabs  716 ,  718  are applied to the idle roller  690 ,  692  to eliminate any static buildup produced during the feeding of the web material  312  over metal rollers. Static buildup can have a negative effect on any solid-state machine controls. 
       FIGS. 21-25  illustrate the modified feed station  630  compared to the prior described feed station  330 . The pinch roller  346  of the prior described embodiment is replaced with a pinch roller  846  having a resilient outer layer for interaction with the web material  312  pinched between the drive roller rings  443  and the pinch roller  846 . The pinch roller  846  can have the resilient outer layer over the entire length or only located at the rings  443  of the driven roller  342 . 
     A scraper or comb plate  850  is mounted stationary in close proximity to the driven roller  342 . The comb plate has a base  852  and finger portions  854 . The finger portions  854  are spaced apart to correspond to the positions of the grooves or recesses  442 . The fingers  854  each proceed into a groove  442  as shown in  FIG. 23A . The fingers  854  act to separate the web material  312  from the surface of the driven roller  342  and direct the web material  312  straight into an alternate cutting nip  855 . A modified shearbar or cutting guide  860  can have a curved, concave groove  862  that forms a deflecting surface that closely conforms to the pinch roller  846  to also help separate the web material  312  from the pinch roller  846  and direct the web material  312  straight into the cutting nip  855 . The cutting nip  855  is defined between the loaf guide  166  and the comb plate  850 , and the cutting guide  860 . 
       FIGS. 26-28  illustrate further aspects of the modified feed station  630 . The feed station  630  is shown in both the closed (solid) and open positions (dashed). The open position is for the purpose of initially threading the web material  312  between the elements of the cutting nip  855  and between the rollers  342 ,  846 . The cutting guide  860  is mounted to opposite inside support plates  862 ,  864  by being clamped between a bridge plate  866  that is fastened to the support plates  862 ,  864 , and a clamp plate  868 . Three fasteners  870  clamp the clamp plate  868  to the bridge plate  866 , capturing the shear bar  860 , which can be dovetailed into the clamp plate  870 . To replace the shearbar  860 , when the feed station  630  is opened, the fasteners  870  are loosened. This loosens the clamp plate  868  and the shearbar  860  can be slid out to the side. For simplicity, the concavity  862  is not shown in  FIG. 28 . Also, the pinch roller  846  spans between and is rotatably mounted to the support plates  862 ,  864 . 
     As shown in  FIG. 27 , the support plates  862 ,  864  include perpendicular arms  862   a ,  864   a  that rotatably mount opposite ends of an idle roller  876 . The idle roller  876  is an additional roller compared to the prior described feed station  330 . When in the open condition, the web material  312  is pulled over the idle roller  876  and over the shearbar  860 . When closed, the shearbar  860  forms the cutting nip with the loaf guide  116 , the rollers  342 ,  846  pinch the web material  312 , and the idle roller  376  wraps the web material  312  and directs the web material over the idle roller  336 . 
     Numerous modifications may be made to the foregoing system without departing from the basic teachings thereof. Although the present invention has been described in substantial detail with reference to one or more specific embodiments, those of skill in the art will recognize that changes may be made thereto without departing from the scope and spirit of the invention as set forth in the appended claims.