Patent Publication Number: US-10780603-B2

Title: Interleaver system for high speed slicing machine having brake for web supply

Description:
RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 14/605,547, filed Jan. 26, 2015, which is a continuation of U.S. patent application Ser. No. 13/214,748, filed Aug. 22, 2011 (now U.S. Pat. No. 9,044,872) which claims the benefit of U.S. Provisional Patent Application No. 61/375,517, filed on Aug. 20, 2010, the contents of all of which are incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     This invention relates in general to food slicing apparatus, and more particularly to the slicing of foods with interleaving sheets. 
     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 FX 180®, FX Plus®, PowerMax3000™ and Powermax4000™ slicing machines available from Formax, Inc., of Mokena, Ill., USA. The FX 180® and the FX Plus®, PowerMax3000™ and Powermax4000™ 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. Reliability of the placement sheets for interleaving with product slices is improved using a feedback loop system to regulate the degree of tension in the interleave web with more precision. 
     The present inventors have recognized that the incorporation of a frictional braking system within the feedback loop system improves the control of the speed of the dispensing reel. 
     The present inventors have recognized the need for a more efficient arrangement of apparatus components when more than one loaf is being sliced. A coaxial arrangement for a slicing machine that slices two or more side-by-side loaves allows for the slicing machine to take up less space and provide easier access to machine components. 
     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. 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 system 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 system includes a supply of web material, a tension control station, a drawing station, an accumulation station, a feed station, and a controller. 
     The drawing station has a first driver which draws the web material from the supply through the tension control station. The feed station has a second driver for receiving the web material from the drawing station via the accumulation station and drives the web material through a cutting nip into the slicing plane. The controller is in signal communication with at least one of the first driver and a sensor that determines the length of web material within the accumulation station. The supply of web material comprises a braking mechanism which is also in signal communication with the controller. 
     The controller is in signal communication with the first driver to maintain the length of web material within the accumulation station within a range of length, as well as with the braking mechanism to maintain the tension in the web between the supply and the drawing station to a pre-selected tension value. 
     A slackened supply of web material is available in the accumulation station and its length is monitored by the sensor which is in signal-communication with the controller. The speed of the first drive is adjusted to maintain the slackened length within a preselected range. 
     The tension control 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 web supply can be controlled. Tension of the web material in the tension control station is controlled by use of a dancer roller that exerts a pre-selected force on the web throughout a range of travel of the dancer roller. 
     The tension control station comprises a series of rollers and the dancer roller which adjusts in position over a range of movement while providing the desired degree of tension between the web supply and the drawing station. The dancer roller is biased by a positioning mechanism which is in signal communication with the controller. The controller is also in signal communication with the braking mechanism to form a continuous feed back loop system for adjusting the position of the dancer roller and for adjusting the braking mechanism. 
     The braking mechanism can be a frictional braking mechanism where brake pads mounted to braking blocks are used to generate a source of friction. Braking blocks are connected to an actuating mechanism which causes braking blocks to extend and retract, thereby allowing the brake pads to come in and out of contact, respectively, with the reel of web material. 
     The position of the dancer roller is controlled by movement of a pair of levers which pivots about a pivot attachment. A lever arm is clamped and pinned to the pivot attachment to rotate therewith. The lever arm is rotably attached to an extendable rod of a position sensing pneumatic actuator. Controlled pneumatic pressure delivered to the actuator extends an extending force on the actuator rod, which in turn moves the lever arm. Movement of the lever arm causes the pivot attachment, and accordingly the dancer roller, to move. The constant force form the actuator causes a the dancer roller to provide a constant tension on the web. 
     The feed station can comprise a drive roller and a nip plate device with the web material fed therebetween. The drive roller rotates to drive an extended end portion of the web material through a cutting nip. An upper frame member rotatably mounts the drive roller. A lower frame member mounts the nip plate device. The lower frame member is pivotally mounted to the upper frame member. Pivoting the lower frame member away from the upper frame member opens the cutting nip and the space between the drive roller and the nip plate device to allow the web material to be threaded between the drive roller and the nip plate device, 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. 
     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 in the accumulation station. 
     According to another aspect of the invention, in slicing machines where side-by side loaves of food product are processed, actuating mechanisms can be arranged coaxially to allow for a more efficient use of space. 
     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  is a side view of a high-speed slicing apparatus suitable for incorporation of the sheet interleaving mechanism of the present invention 
         FIG. 2  is an opposite side view of the high-speed slicing apparatus of  FIG. 1 , incorporating the sheet interleaving mechanism of the present invention. 
         FIG. 3  is a perspective view of one embodiment of the braking mechanism and spool. 
         FIG. 4  is a top view of one embodiment of the braking mechanism. 
         FIG. 5  is a perspective view of the actuators for the braking mechanism and the dancer assembly. 
         FIG. 5A  is an enlarged top view of one embodiment of the braking mechanism. 
         FIG. 5B  is a side view of the actuator for the braking mechanism. 
         FIG. 6  is a perspective view of the web material threaded through the tension control station. 
         FIG. 7  is a side view of the web supply, the tension control station, and the drawing station. 
         FIG. 8  illustrates the range of motion of the dancer assembly. 
         FIG. 9  illustrates one embodiment of a feedback loop system for use with the interleaving mechanism. 
         FIG. 10  is a perspective view of the dancer assembly. 
         FIG. 11  is a top view of the dancer assembly. 
         FIG. 12  is a side view of the drawing station. 
         FIG. 13  is a side view of the sensor station. 
         FIG. 13A  is an alternate embodiment of accumulation station 
         FIG. 14  is a perspective view of motors which drive the rollers in the drawing station. 
         FIG. 15  is a top view of the drawing station. 
         FIG. 15A  is a top perspective view of the drawing station rollers. 
         FIG. 15B  is a bottom perspective view of the drawing station rollers. 
         FIG. 15C  is a perspective view of motors for driving the drawing station rollers. 
         FIG. 16  is a side view of the feed station. 
         FIG. 17  is a side view of the feed station illustrating the feed station in both its open and closed positions. 
         FIG. 18  is an enlarged view of the guide plate. 
         FIG. 19  is a side view of a high-speed slicing apparatus incorporating the sheet interleaving mechanism of the present invention. 
         FIG. 20  is a side view of the moveable frame assembly. 
         FIG. 21  is a front view of the moveable frame assembly. 
     
    
    
     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; and U.S. Published Patent Application US 2009/0188363 A1, all herein incorporated by reference, to the extent that the references are not contrary to the present specification, or as commercially available as a FX 180®, FX Plus®, PowerMax3000™ and Powermax4000™ slicing machine and/or system available from Formax, Inc. of Mokena, Ill., USA. 
     The slicing apparatus  50  includes a base section  104 , a collapsible frame  105 , an automatic food article loading apparatus  108  that receives food articles to-be-sliced, a food article feed apparatus  120 , a food article feed elevation adjusting apparatus  121 , a laser safety guard system  123 , and a slicing head apparatus  124 . The slicing apparatus also includes a computer display touch screen  131  that is pivotally mounted on and supported by a support  132 . 
     The base section  104  includes a compartment  136  having side walls  138   a , a bottom wall  140 , and an inclined top wall  142 . The apparatus  100  is supported on four adjustable feet  144 . The compartment  136  has a tapered side profile from back to front wherein the top wall  142  slants down from back to front. The slanted orientation of the top wall  142  ensures water drainage off the top of the compartment  136 . 
     The compartment  136  includes near side doors  152 , 154 , far side doors, and a rear door that permit access into the compartment or to modules normally within the compartment  136 . The compartment  136  typically affords an enclosure for a computer, motor control equipment, a low voltage supply, and a high voltage supply and other mechanisms as described below. The compartment may also include a pneumatic supply or a hydraulic supply, or both (not shown). 
     The slicing machine  50  includes a stacking conveyor or jump conveyor  130  ( FIG. 2 ) beneath the slicing head apparatus  124 , particularly beneath a rotating slicing blade  100 . The slicing machine may include an output conveyor/classifier system  102  which receives and transports stacks of slices from the stacking conveyor  130 . 
       FIG. 2  illustrates one embodiment of the sheet interleave system  300  of the present invention. For purposes of description, a single sheet interleaving system 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 sheet interleaving system  300  comprises a web material supply  301 , a tension control station  610 , a drawing station  316 , a web accumulation station  329  and a feed station  330 . 
     The web material supply  301  may be a spool  306  for dispensing web material  312  from a roll  308  as shown in  FIG. 3 . The spool  306  is supported on a cylindrical shaft  310  that allows the roll  308  to revolve about the shaft  310  to dispense web material  312  ( FIGS. 2 and 3 ). Braking mechanisms  309  are disposed within the shaft  310 . The web material  312  extends from the roll  308  and is threaded through a tension control station  610  and then to a drawing station  316 . A non-contact sensor, such as an ultrasonic or optical sensor can be used to sense the diameter of the roll  308  and communicates a signal when the roll is depleted, or when the diameter of the roll falls below a pre-selected value. 
       FIG. 4  illustrates a top view of the interleaver system with two rolls  308   a ,  308   b  of material supply. The rolls  308   a ,  308   b  are each on a spool  306   a ,  306   b  supported along the shaft  310  that is in the form of a common cylindrical shaft. Braking mechanisms  309   a ,  309   b  are used to adjust the speed at which web material  312  is dispensed. 
     Braking mechanism  309  may be a disk, pins, or any other mechanism which can extend from the shaft  310  to generate a frictional force between the cylindrical shaft  310  and the spool  306 . In its resting position, the braking mechanism  309  does not protrude beyond the surface of the cylindrical shaft. In its activated position, the braking mechanism  309  extends beyond the cylindrical shaft to a degree which provides the desired amount of frictional force against the spool  306 . 
     Braking mechanisms  309  are activated using an actuator  311  which is connected to an actuating arm  314 . Actuating arm  314  is disposed within the cylindrical shaft  310  ( FIG. 5 ). In operation, as illustrated in  FIG. 4 , two actuators  311   a ,  311   b  are used to control each of the breaking mechanisms  309   a ,  309   b  to adjust the dispensing rate of rolls  308   a ,  308   b  respectively. The actuators  311   a ,  311   b  are disposed on the same side of the slicing machine. Control for both rolls is made possible by disposing both actuating arms  314   a ,  314   b  within the cylindrical shaft. The first actuating arm  314   a  extends to reach the first braking mechanism  309   a . The second actuating arm  314   b  extends past the first braking mechanism  309   a  to reach the second braking mechanism  309   b . A controller signals to the actuator to expand or contract to activate or withdraw, respectively, the braking mechanism. An extension of the actuating arm can be used to cause the braking mechanism  309  to protrude from the cylindrical shaft  310 . 
     In one embodiment, as illustrated in  FIG. 5A , braking mechanism  309  is a brake pad  309   a ,  309   b . Actuating arms  314   a ,  314   b  extend and terminate at braking blocks  315   a ,  315   b  respectively. Braking blocks comprise action blocks  316   a ,  316   b , and brake pads  309   a ,  309   b . Action blocks  316   a ,  316   b  are shaped with an inclined surface  317   a ,  317   b  such that brake pads  309   a ,  309   b , with a complementary shaped surface, can slide over the inclined surface  317   a ,  317   b . When the actuating arms  314   a ,  314   b  contract, the actuating arms retract in a direction R, pulling the action blocks  316   a ,  316   b  in the same direction. The movement of the action blocks pushes the brake pads outward to generate a frictional braking force which creates drag to stop the roll completely, or causes the roll to pay out the film at a slower pace. Movement of the actuating arms is controlled by the actuator  311 , illustrated in  FIG. 5B . The actuator  311  comprises a bladder  319 , an air pressure inlet  318 , and a threaded shaft  320 . The threaded shaft  320  extends from one end of the bladder  319  and is connected to the actuating rods. The air pressure inlet  318  is disposed on the opposite end of the bladder. As air pressure is increased, the bladder expands vertically or contracts to pull the threaded shaft from point “A” to point “B” proportional to the amount of air pressure applied. The actuator can be FLUIDIC MUSCLE DMSP, MAS such as those available from Festo Corporation in Hauppauge, N.Y. 
     The web material  312  extends from the roll  308  and is threaded through a tension control station  610  as illustrated in  FIGS. 2 and 6 . The station  610  includes a housing or frame  611 . The web material  312  is first threaded across a first fixed upper idle roller  632  and a second fixed upper idle roller  634  ( FIGS. 6 and 7 ). The web material  312  is then directed downward to wrap a dancer roller  636  and then directed upward to wrap a first lower fixed idle roller  638 . The web material  312  is then directed downward to wrap a second lower fixed idle roller  640  and then directed upwards to feed station  330 . The dancer roller  636  is mounted across a pair of levers  642  that can be pivoted about by a pivot attachment  646  to the frame  611 . A lever arm  656  is clamped and pinned to the lever pivot attachment  646  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 . 
     As shown  FIG. 5 , 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 connected to support bar  667  which is attached to the frame  611 . A pre-selected pneumatic pressure delivered into the cylinder  666  urges the rod  662  outwardly. Pressurized air is pneumatically connected by a circuit to the cylinder  666 . The circuit includes a pressure compensating pressure regulator  669  (shown schematically) which delivers 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  FIG. 5 . Given typical surrounding parameters, this pressure can be about 12 psig. The reselected pressure sets the desired tension in the web over the pre-selected range of movement of the arm  656 . The arm  656  rotates the pivot attachment  646 , which in turn positions the dancer roller  636  to provide the appropriate tension. As illustrated in  FIG. 6 , dance roller  636  may have a range of motion along the circular path illustrated by the arrows.  FIGS. 7 and 8  illustrate three positions  637   a ,  637   b ,  637   c  as an example of the range of motion. Shock absorbers (not shown) can be used and engaged by extreme positions of the lever arm  656  or the tail portion  657  to cushion the end of travel of the arm  656  and tail portion  657 , resulting in better tension control. Grounding tabs (not shown) can be applied to the idle rollers to minimize static buildup during the feeding of the web material  312  over the rollers. The actuators  664  can be position sensing pneumatic cylinders, such as a POSITION FEEDBACK CYLINDER sold by Bimba Manufacturing Company of Monee, Ill., US. 
     For slicing machines that slice two or more side-by-side loaves, multiple sheet interleaving apparatuses  300  can be provided in a corresponding side-by-side arrangement. A side-by-side arrangement is illustrated in  FIGS. 10 and 11 . In a side-by-side arrangement, one pivot arrangement extends through the center of the adjacent pivot arrangement. Pivot arrangement  646   b  is a cylindrical shaft with a diameter less than that of pivot arrangement  646   a , such that pivot arrangement  646   b  can extend coaxially through the cylindrical shaft of pivot arrangement  646   a . Pivot arrangement  646   a  with pivot arrangement  646   b  disposed within, extends exterior to the frame to connect with lever arms  656   a ,  656   b . Pivot arrangement  646   a  extends at least up to lever arm  656   a . Lever arm  656   a  engages with pivot arrangement  646   a  to move corresponding dancer roller  636   a . Pivot arrangement  646   b  extends from pivot arrangement  646   b  to engage with lever arm  656   b . Lever arm  656   b  engages with pivot arrangement  646   b  to move corresponding dancer roller  636   b . The coaxial arrangement allows for multiple sets of actuating mechanisms  611   a ,  611   b  ( FIG. 11 ) to be on the same side of the machinery frame, thus saving space, simplifying wiring and tubing hook up, and providing for easier maintenance. 
     After being threaded through the tension control station  610 , the web material extends into the drawing station  316  before it reaches the sensor station  600 . The drawing station is illustrated in  FIGS. 12, 13, and 15 . The web material  312  entering the drawing station  316  is wrapped around a drawing station fixed idle roller  690 . After the fixed idle roller  690 , the web material  312  is wrapped around the driven roller  502 . Driven roller  502  forms a nip  501  with a nip roller  503 . The nip roller  503  is a fixed idle roller disposed against the driven roller  502 . Nip roller  503  is held in position using a bracket  504  mounted to a support  505 . Support  505  extends from the sensor housing  506 . 
     Bracket  504  extends and retracts horizontally towards and away from the driven roller  502  as illustrated by the double headed arrow in  FIG. 15A . The support  505  to which the bracket  504  is mounted, moves towards and away from the sensor housing  506  to move the bracket  504 . When the bracket  504  is moved towards the driven roller, a nip is formed therebetween. To remove the roller  503  from contact with the driver roller  502 , the support  505  retracts towards the sensor housing  506 . The sensor housing comprises air inlets which are connected to an air supply source (not shown). Air entering the inlet is used to operate an actuating mechanism  513  (shown schematically in dashed lines in  FIG. 15A ). Actuating mechanism  513  can be a pneumatic cylinder with a push rod connected to the sensor housing side of the support. Extension and retraction of the push rod causes the support  505  to retract and extend. 
       FIGS. 7 and 15B  illustrate the bracket  504 . The bracket  504  extends below the nip roller  503  on either side of the nip roller  503  to form a lower bar  509 . The lower bar  509  has an edge  514  in close proximity to the surface of the driven roller  502 . The edge  514  is used to prevent the web material from being wrapped around the driver roller  502  when the web material has a free edge, such as during initial threading of the web material through the interleaving apparatus. The edge  514  of the lower bar  509  of the bracket  504  assists to ensure that web material  312  goes past the two rollers  503 ,  502  in a downward direction as illustrated by the arrow in  FIG. 15B , towards the sensor station  600 . 
     Driven roller  502  is driven by a drawing station motor  507 . In side-by-side arrangements having more than one driven roller ( FIG. 15 ), a motor  507   a ,  507   b  is used to drive each driven roller  502   a ,  502   b  ( FIG. 15C ). Driven roller  502   a  is mounted on a shaft  520   a  which spans the length between the two sides  521   a ,  521   b  of the interleaver apparatus frame. Shaft  520   a  is coupled such that only driven roller  502   a  is driven by the rotating motion of the shaft  520   a . The shaft  520   a  passes through a support  522  and driven roller  502   b , but does not engage with driven roller  502   b  in a manner that would impart motion to the roller. Driven roller  502   b  is supported in position by the support  522  and by connection to side  521   b  of the interleaver apparatus frame, thus allowing driven roller  502   b  to be suspended above shaft  520   a  without contacting shaft  520   a . Other configurations for preventing shaft  520   a  from imparting its motion to driven roller  502   b  are also possible. Motor  507   b  drives a shaft  520   b  which imparts its motion to driven roller  502   b  by way of a pair of sprockets  523 ,  524  joined by a belt or chain  525 . Sprocket  524  is disposed on the end of the shaft  502   b  opposite the motor  507   b , and drives a belt or chain  525 . Sprocket  523  is disposed on one end of driven roller  502   b , such that any motion imparted to the sprocket  523  via the belt or chain  525  drives the drive roller  502   b . Other suitable arrangements for imparting motion to driven roller  502   b  can be used, such as, for example, the use of a gear train. 
     The web accumulation station  329 , between the nip  501  and an intermediate idle roller  342 , provides a length of slackened web material between the high intermittent speed feed station  330  and the constant speed drawing station  316 . The accumulation station  329  includes a sensor station  600  that is used to sense the slackness, or accumulation, of the web material  312 . 
       FIG. 13  illustrates the sensor station  600 . The sensor station comprises a sensor  601  disposed within the sensor housing, along with an air nozzle  602 . The sensor  601  can be an ultrasonic sensor, an optical sensor, such as a laser or photo eye, or other type of sensor. The sensor can be a GV SERIES DIGITAL CMOS LASER SENSOR such as those sold by Keyence Corporation. 
     The sensor  601  can project an ultrasonic or optical beam signal downwardly toward the web loop  605  formed between the two rollers  342 ,  502 . As illustrated in 
       FIG. 13 , the sensor  601  is a laser distance transmitter which generates a laser distance sensor beam  607 . The sensor beam  607  measures the web material&#39;s lowest position. The sensor  601  communicates with a control which is in signal communication with the drawing station motor  507 . For example, web position  312   a  has less web accumulation than web position  312   b . If the slackness approaches the condition  312   a , the drawing station motor  507  can be increased in speed to unwind material at a greater rate. If the slackness condition approaches condition  312   b  the motor  507  can be slowed. To maintain the web loop in a substantial V-shape, steady for sensing purposes, between the drawing station motor  507  and the feed station motor  360 , a stream of air  608  from the air nozzle  602  is directed downwards within the web material  312 . As seen in  FIG. 13 , in the accumulation station  329 , the slackened length of web material  312  defines a curve, which has a first surface, and a second surface on a side of the web material  312  opposite the first surface. The first surface of the slackened length of web material  312  is defined as being the concave side of the curve while the second surface is on the opposite side, namely the convex side. The downwardly emitted beam  607  from sensor  601  meets the curve of the slackened length of the web material, meaning the first surface, at a vertex  609  of the curve 
       FIG. 13A  illustrates an alternate embodiment of the accumulation station which uses a reflective photo eye sensor. The same reference designations refer to the same parts as previously discussed. A web accumulation station  329 A, between the nip  501  and an intermediate idle roller  342 , provides a length of slacked web material between the high intermittent speed feed station  330  and the constant speed drawing station  316 . The accumulation station  329  includes a sensor station  600   a  that is used to sense the degree of slackness, or accumulation, of the web material  312 . 
     The sensor station  600   a  comprises a sensor which is a reflective photo eye  601   a  disposed to cast a horizontal beam into the area of accumulation of the web material  312 . The photo eye  601   a  is used in conjunction with a reflective surface  603 . The photo eye  601   a  and the reflective surface are disposed on opposite sides of the area of accumulation of the web material. The reflective surface is oriented vertically and perpendicular to the path of the beam such that the beam of light contacting the reflective surface will be reflected back to the photo eye sensor. When the length of slacked web material forms a loop with a lowest point above the beam path, such as when the bottom of the loop is in position A, the beam of light from the photo eye to the reflective surface is uninterrupted, and the beam of light is reflected back to the photo eye and sensed. When the length of slacked web material forms a loop of sufficient slackened length so as to form a loop which interrupts the beam path, such as when the bottom of the loop is in position B, no light is reflected back to the photo eye. In the absence of a reflective beam, the driving station motor  507 , or the payout motor, is sent a signal to pay out web material at a slower rate. When the beam is reflected back to the sensor, the loop of web material has not accumulated a sufficient length to interrupt the beam path, and the driving station motor  507  is sent a signal to pay out web material at a faster rate. The photo eye can emit any electromagnetic beam, such as an infrared beam. Any other method of sensing the slackness of the web accumulation loop can also be used. 
       FIG. 9  illustrates in schematic form that a controller  800  receives a position signal  820  regarding the position of the dancer roller  636  based on the extension of the actuator rod  662  as a result of the degree of pivot of the pivot attachment  646 . The controller sends a signal  830  to the actuator  311  for the braking mechanism of the spool, which allows the controller to adjust the rate the roll  308  is unwound in response to position information of the dancer roller  636 . The controller  800  also can receive a signal  840  with the sensor  601  in the sensor station  600  and the feed station motor  850 . The sensor  601  detects the slacked length of the web material between the drawing station and the feed station, and communicates the signal  840  to the controller  800 . The controller signals the drawing station  301  that more or less web is needed to maintain the slacked length within a desired range. The controller can be a computer  54 . 
     By having a feedback system, the pre-selected level of tension in the interleaver web can be maintained due to the real time communication of positioning information. In one embodiment, the feedback loop may involve only the tension control station and the dispensing of web material from the reel to adjust the slack in the web material. 
     After the web material leaves the intermediate roller  342 , the web material enters the feed station  400 , illustrated in  FIGS. 16 and 17 . Feed station  400  comprises a feed roller  420  driven by an endless belt  500  connected to a drive motor  410 . Idle roller  530  is positioned in contact along the endless belt  500  pathway to provide tension in the endless belt  500 . 
     A nip  470  is formed by the contact of the feed roller  420  and the upward edge  471  of the nip plate device  430 . The feed roller  420  can be coated to provide friction at the nip  470 . The feed roller  420  may be coated with rubber, or other properties with similar desirable characteristics. 
     A nip plate device  430  is used to guide the web material  312 . Web material  312  glides along the nip plate device  430  towards the nip  470 . Nip  470  opens and closes as a result of movement of the nip plate device  430 . Nip plate device  430  pivots or tilts about a pivot axis  535 . The nip plate device  430  is attached to a support block  536  via a pair of screws  537  ( FIG. 16 ). The pivot axis  535  passes through the support block  536 . Movement of the support block  536  about the pivot axis  535  tilts the upward edge  471  of the nip plate device towards and away from the feed roller  420 . A counterclockwise rotation of the nip plate device about the pivot axis  535  causes the upward edge  471  to move away from the feed roller  420 . A clockwise rotation of the nip plate device  430  about the pivot axis  535  causes the upward edge  471  to move towards the feed roller  420  to create a nip. Pneumatic cylinders  510  ( FIG. 17 ) connected to a coupling  538  ( FIG. 16 ) are used to actuate pivotal movement of the nip plate device  430 . 
     The nip plate device  430  has a raised edge  460  which assists in supporting the web material  312  as it is directed towards the nip  470 . Raised edge  460  decreases the slack in the web material  312  in the distance between idle roller  456  and the nip  470 . Alternately, the raised edge  460  of the nip plate device  430  can be used to stop the nip plate device  430  from pivoting in a clockwise direction beyond a certain point. The nip plate device  430  comprises a shear edge  490  disposed on the end of the nip plate device opposite the raised edge  460 . The shear edge  490  can be made of a plastic or polymeric material. The shear edge  490  forms a cutting nip  480  where the web material  312  is cut. 
       FIGS. 16 and 17  illustrate the feed station it is closed position ( FIG. 16 ) and both closed and open positions ( FIG. 17 ). The open position allows for the initial threading of the web material through the feed station up to the nip  470  formed between the feed roller  420  and the upward edge  471  of the nip plate device  430 , as well as for threading the web material between rollers  455 ,  456 . 
     As the web  312  enters the feed station  400 , a guide plate  450  directs the web material  312  to a pair of idle rollers  455 ,  456  which assist in maintaining the tension of the web material  312  in the feed station  400  ( FIG. 16 ). After the web material is threaded past the idle rollers  455 ,  456 , the raised edge  460  of the nip plate device  430  guides the web material towards a nip  470  formed between the feed roller  420  and the upward edge  471  of the nip plate device  430 . 
       FIG. 18  illustrates an enlarged view of the guide plate  450 . Web material  312  enters the feed station by coming into contact with the guide plate  450 . Guide plate  450  has a curved edge  452  to allow better reception of incoming web material  312 . The web material glides along the guide plate towards idle roller  455 . To prevent the web material from slipping off the guide plate, the guide plate  450  has side rails  453  to keep the web material on the guide plate. 
     The guide plate  450  is pivotable about a pivot axis  451 . The pivot axis is disposed closer to one end of the guide plate than the other. The pivot axis is disposed closer to the end of the guide plate opposite the curved edge. As a result, the curved edge  452  end of the guide plate  450  in its natural state is inclined to tilt downwards due to gravity, towards a position shown in dashed lines in  FIG. 18 . The natural inclination towards a downwards tilt of the curved edge  452  end causes the opposite end to tilt upwards to form a nip  454  with idle roller  455 . The inclination towards forming a nip is useful when initially threading the interleaver apparatus. A user threads the web material  312  from the sensor station  600  towards the guide plate  450 . To thread the web material  312  from the guide plate towards the rest of the assembly in the feed station, the user typically moves towards the feed station end of the apparatus to pull the web material  312  from the nip  454 . The nip  454  holds the web material  312  until the user reaches the other side of the feed station to pull the web material  312  from the other end. Without the nip  454 , the web material may slip off the guide plate. The use of the nip  454  enables one user to thread the machine. When the interleaver apparatus is in motion, the guide plate is pivoted to the position shown in solid lines in  FIG. 18 , wherein the guide plate  450  is no longer in contact with idle roller  455  to form a nip. This allows web material  312  to pass through the idle roller  455  towards the second idle roller  456 . 
       FIG. 19  illustrates a side view of the slicer and the interleaver apparatus. The material supply  301 , tension control station  610 , drawing station  330 , and sensor station  600  are all mounted to a moveable frame assembly  700 . The slicing machine  50  is connected to pivot arms  701 ,  702  which allow the slicing machine to move from its raised position (as illustrated in  FIG. 19 ) to a lowered position (not shown) where the slicing machine  50  is more accessible for maintenance and repairs. In its raised position, the material supply  301 , tension control station  610 , drawing station  316  and sensor station mounted on the moveable frame assembly  700  can fit in the space underneath the raised portion of the slicing machine  50  and above the base  51 . When the slicing machine  50  is to be lowered for maintenance or repairs, there is no longer room for the interleaver components to be disposed beneath the slicer machine  50 . The moveable frame assembly  700  comprises a lower portion  720  which houses electrical components. The upper portion  730  of the frame assembly comprises a support frame  611  to which components of the tension control station, drawing station, and sensor station are connected. 
     Support frame  611  is connected to a housing  765  which pivots about a pivot shaft  760  ( FIGS. 20 and 21 ). The pivot shaft connects the upper portion  730  of the frame assembly to the lower portion  720  of the frame assembly. The upper portion  730  of the frame assembly can be pivoted about the pivot shaft  760  while the lower portion  720  of the frame assembly remains stationary. The upper portion  730  can be pivoted about the pivot shaft to allow for easier maintenance of the components within the upper portion  730  of the frame assembly, or to allow at least some lowering of the slicing machine  50 . The pivot shaft  760  is a hollow cylinder which can be used as a conduit for the passing of cables and tubes between the upper and lower portions  730 ,  720 . 
     To ensure that the upper portion  730  of the frame assembly does not inadvertently pivot when movement is not desired, a pin  740  is used to lock the loose end of the upper portion  730  in position. An arm  770  extending from the support frame  611  is a cylindrical shaft through which a pin  740  is passed to lock the frame  611  in place. The pin  740  passes through the cylindrical shaft arm  770  of the housing  611  and is secured to a pin mount  775  connected to the top surface  776  of the lower portion  720 . The pin  740  is secured to the pin mount  775  by a threaded coupling. Other methods of securing the frame  611  to prevent unwanted movement about the pivot shaft can also be used. 
     The upper and lower portions  730 ,  720  of the frame assembly rest on a pair of forked prongs  780 , which provide stability to the moveable frame assembly  700 . The forked prongs  780  are of a distance above the floor such that the forked prongs  780  are able to slide underneath the base  51  of the slicing machine  50 . By sliding the forked prongs  780  underneath the base  51  of the slicing machine, the frame assembly is able to be positioned close to the slicing machine. Caster wheels  750  on the underside of the forked prongs  780  allow for the entire assembly to move. 
     From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the invention. It is to be understood that no limitation with respect to the specific apparatus illustrated herein is intended or should be inferred. 
     All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.