Patent Document

BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to web handing apparatus and to a method for web handling. More particularly, the present invention relates to web handling apparatus and a web handling method wherein the speed of movement of a downstream portion of a moving web of material is varied while the upstream portion of the web that approaches the web handling apparatus is maintained at a constant web speed. 
     2. Description of the Related Art 
     It is often desirable in various manufacturing operations to control the speed of a moving web of material to temporarily change the speed of the web in response to a particular operating condition, or to enable the performance on the web of a particular operation. In that regard, the web speed can be changed in a number of ways, including varying the speeds of intermediate feed rolls that guide the web along, sometimes with web storage apparatus such as dancer rolls, shuttle devices that reciprocate to temporarily shift the web, or the like. Alternatively, the speed of a moving web can be changed by varying the speed of a drive motor that drives an unwind stand or a web take-up roll that causes web movement through the web handling apparatus. 
     Although web-speed-change devices are known, the use of such known devices often involves web speed changes that are achieved by periodically accelerating and decelerating various of the rotating elements of the web feed system. As a result, varying cyclic loads are imposed on the respective rotating elements of the web feed apparatus, and those varying loads cause varying levels of cyclic stress on those elements. The varying stress levels, which also are influenced by the magnitude of the output and speed of the drive motor, can, over time, lead to the need for more frequent maintenance and replacement of parts because of increased wear that occurs as a result of the changing stress levels. Additionally, to periodically accelerate rotating elements to effect web speed changes requires a larger size, more costly drive motor that provides a higher output power than would be required if the rotational speeds of the rotating elements were maintained substantially constant. 
     Accordingly, it is desirable to provide apparatus that allows the speed of a web to be controlled to a desired value at a particular point in a manufacturing process, either greater than or less than the speed of the incoming web, while maintaining the incoming web speed at a constant value. Consequently, rotational speed changes within the web feed mechanism are desirably avoided, to minimize the stresses on and the resulting wear of the rotating elements of the apparatus, and to reduce the need for frequent servicing and repair of rotating elements of the apparatus. 
     It is also desirable to eliminate the need for reciprocating web-take-up devices, such as dancer rolls and shuttles that are sometimes employed in web feed devices to allow changes of web output speed while maintaining the web input speed substantially constant. An example of one such reciprocating, shuttle-type device is disclosed in U.S. Pat. No. 5,693,165, entitled “Method and Apparatus for Manufacturing an Absorbent Article,” which was issued on Dec. 2, 1997, to Christoph Schmitz. 
     Another proposal for periodically changing the speed of a web while the web infeed speed is maintained constant is disclosed in U.S. Pat. No. 5,407,513, entitled “Apparatus and Process for Cyclically Accelerating and Decelerating a Strip of Material,” which issued on Apr. 18, 1995, to Michael P. Hayden et al. The apparatus disclosed in that patent includes an eccentric accelerator in the form of a spindle that is carried on a rotating drive shaft and that is offset from the axis of rotation of the drive shaft. Accordingly, as the drive shaft rotates the periphery of the spindle describes a circle that is concentric with the axis of the drive shaft. The apparatus disclosed in that patent is utilized in the context of apparatus for changing the speed of a web of a fastener material that is to be applied at spaced intervals to a second moving web. Because of the spacing of the fasteners that are cut from the web of fastener material, the incoming speed of the fastener material is maintained constant while the web passes over the eccentric accelerator to periodically accelerate and decelerate the web of fastener material to enable a cut to be made so that the cut portions are properly positioned relative to a base sheet with which the cut portions are associated. However, in that apparatus the cut that is made in the web is a transverse cut that extends perpendicularly to the web movement direction, and the eccentric accelerator causes the fastener web to only instantaneously match its speed with that of a cutter and anvil roll combination that effects the transverse cuts in the fastener material. As a result, the Hayden et al. device does not permit cuts to be made that are at an angle with the web movement direction and that take place over a given period of time, as opposed to instantaneously. 
     An object of the present invention to provide a method and an apparatus that allows a constant web infeed speed with varying web output speeds, and that will enable an angular cut to be made in the web material by matching the web speed to the surface speed of a downstream operation for a predetermined time period. 
     It is another object of the present invention to provide a web feed system for changing a web output speed while maintaining web input speed constant and while maintaining at a substantially constant value the rotational speeds of the rotating elements of the system. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the present invention, a web speed metering apparatus is provided for receiving and engaging a web that is supplied to the metering apparatus at a constant in-feed speed. The output speed of the web leaving the metering apparatus is cyclically varied. The apparatus includes a rotatable shaft that defines an axis of rotation and that is disposed across a path of movement of a web of material to be metered. An elongated, web-engaging surfaces is carried on the shaft and extends axially thereof to define a surface having a constant cross-sectional configuration in a direction perpendicular to the axis of rotation. The web-engaging surface is adapted to receive an incoming web that travels at a constant in-feed speed and defines a non-circular cross-section in a direction perpendicular to the axis of rotation. The cross-section has a centroid that is offset from the axis of rotation to cause the output speed of the web as the web leaves the web-engaging surface to vary as a function of the instantaneous radial spacing of the web from the axis of rotation of the web-engaging surface. 
     In accordance with a further aspect of the present invention, a method is provided for varying the output speed of a first moving web having a constant input speed and a timed relationship with a web processing station for a continuously moving second web that is supplied at a constant in-feed speed. The method includes the steps of feeding the first moving web at a first constant speed to a web deflection station for a predetermined first time period to allow an operation to be performed on the web downstream of the deflection station. An intermediate portion of the moving web is deflected so that the speed of the leading edge of web is decreased for a predetermined second time period to a speed less than that of the first constant speed to allow a predetermined leading edge advancement length. Deflection of the moving web is terminated and the leading edge of the web is fed at the first constant speed for the predetermined first time period. The leading edge of the moving web is advanced at predetermined distance and is fed at the first constant speed for the predetermined first time period. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic, side elevational view of an apparatus that includes a web speed metering apparatus in accordance with the present invention in association with web cutting and web feeding apparatus. 
     FIG. 2 is a top view of a web showing one possible form of cut to be made in the moving web utilizing apparatus in accordance with the present invention. 
     FIG. 3 is a view parallel to the machine axis illustrating the external peripheral configuration of a web deflector in accordance with one embodiment of the present invention. 
     FIGS. 4 through 11 are sequential views showing the positions of the various elements of the cutting apparatus, a web deflector, and the web that is deflected during a complete operating cycle of the cutting apparatus. 
     FIG. 12 is a view parallel to the machine axis illustrating the external peripheral configuration of a web deflector in accordance with another embodiment of the present invention, defined by a belt configured by a series of spaced parallel rolls. 
     FIG. 13 is a cross-sectional view perpendicular to the machine axis illustrating the drive configuration of a web deflector in accordance with another embodiment of the present invention defined by a series of spaced parallel rolls. 
     FIG. 14 is a view taken along the line  14 — 14  of FIG. 13 illustrating the drive configuration and the external peripheral configuration of a web deflector shown in FIG.  13 . 
     FIG. 15 is a cross-sectional view perpendicular to the machine axis of another embodiment of a web deflector in accordance with the present invention. 
     FIG. 16 is a cross-sectional view perpendicular to the machine axis taken along the line  16 — 16  of FIG.  15 . 
     FIG. 17 is an elevational view of the web deflector shown in FIG. 16, taken perpendicular to the machine axis. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, and particularly to FIG. 1 thereof, there is shown cutting and joining apparatus  10  for cutting sections of predetermined shape and length from a first continuously moving web  12  and for associating the sections cut from the first moving web with a second moving web  14 . The illustrated arrangement will be described in the context of an angular cut across the first web, such as to cut a chevron-shaped section from the first continuously moving web, and associating successive sections cut from the first web in spaced relationship relative to each other and successively along the machine direction of a second continuously moving web. The first and second webs each move at a constant speed, but the second web moves at a faster speed than that of the first web. The second web can serve as a carrier web that carries a series of spaced elements with which the sections cut from the first web are to be associated. 
     The illustrated apparatus can advantageously be utilized in the manufacture of disposable diapers. For example, chevron-shaped fastener components can be cut from the first moving web when it is a fastener component material, and the cut components can be transferred in spaced relationship, relative to each other, to a second moving web that is a liquid-impervious backsheet material. However, although disclosed in the context of disposable diaper manufacture, it will be appreciated by those skilled in the art that the arrangement shown, as well as individual elements thereof, can be utilized in connection with many other different types of products in which pieces cut from one moving web are to be associated in some way with another moving element or another moving web. 
     First moving web  12 , which travels at a first constant speed and which can be in the form of an overlay material, is fed to the cutting and joining apparatus  10  from a web supply source (not shown), such as an unwind stand. Web  12  passes over a pair of spaced, parallel first and second idler rolls  16 ,  18  to a third idler roll  20 . Between second and third idler rolls  18 ,  20  there is shown a glue applicator  22  that can optionally be provided in order to apply a layer of glue, or, alternatively, a predetermined glue pattern, to the adjacent surface of web  12 . After passing over third idler roll  20 , web  12  engages and passes over the outer surface of a web deflector  24 . 
     Web deflector  24  is carried on a rotatable shaft  26 , and it has a cross-sectional area the centroid of which is offset from the axis of rotation of shaft  26 . The dashed circle  28  surrounding the axis of shaft  26  describes the circular pathway swept by the radially-outermost surface of web deflector  24 . 
     After passing over a portion of the outer surface of web deflector  24 , first web  12  progresses over a guide bar  30  and then comes into contact with the outer cylindrical surface of an anvil roll  32  that is adjacent to the outer peripheral surface of a similarly-sized cutter roll  34 . Anvil roll  32  has a pair of diametrically-oppositely-disposed peripheral anvils  36 ,  38 , and cutter roll  34  has a corresponding number of diametrically-oppositely-disposed peripheral cutting knives  40 ,  42  that are so positioned on the periphery of cutter roll  34  as to periodically engage respective ones of anvils  36 ,  38  as cutter roll  34  and anvil roll  32  rotate together in the directions shown by the arrows in FIG.  1 . 
     Guide bar  30  that is positioned between web deflector  24  and anvil roll  32  is connected with a source of pressurized air (not shown) in order to lightly lift the moving first web  12  away from the surface of guide bar  30  and to support moving web  12  without significant frictional drag as the web passes toward anvil roll  32 . In that regard, guide bar  30  serves to maintain moving web  12  in a predetermined position immediately upstream of anvil roll  32  and also to provide a web guide surface to prevent relatively flexible webs from being diverted downwardly, as viewed in FIG. 1, away from the desired path of web travel, after a forward portion of the web material has been cut, as will hereinafter be described. 
     Cutting knives  40 ,  42  carried by cutter roll  34  serve to cut sections  44  of predetermined size and shape from first web  12 , after which anvil roll  32  carries cut sections  44  to a nip defined between the periphery of anvil roll  32  and the periphery of a transfer roll  46  that is in contacting peripheral engagement therewith. Transfer roll  46  receives second moving web  14  from a source (not shown), such as an unwind stand, or the like. Second moving web  14  travels at a second constant speed and passes from transfer roll  46  to a downstream processing station (not shown) at which additional operations and manipulations can be performed on web  14 . As shown in FIG. 1, second moving web  14  receives cut sections  44  that are pressed against se¢cond moving web  14  between anvil roll  32  and transfer roll  46 , and that adhere to second moving web  14  by virtue of the glue that had been applied to the outwardly facing surface of first moving web  12  by glue applicator  22 . As also apparent from FIG. 1, the several cut sections  44  are positioned on second moving web  14  in spaced relationship, at a predetermined spacing along the machine direction of second moving web  14 . 
     The illustrated arrangement is particularly adapted to enable cuts to be made in first moving web  12  that extend at an acute angle to the machine direction of that web. For example, and as shown in FIG. 2, when cutting knives  40 ,  42 , carried by cutter roll  34 , are chevron-shaped, they can provide chevron-shaped cut sections  44 . Alternatively, cutting knives  40 ,  42  can be of bowed, curved form, or of any other form wherein the cut that is made includes a component of the cut that extends for some predetermined distance along the machine direction of the web. The cutting process occurs progressively as anvil roll  32  rotates with web  12  carried on the peripheral surface of roll  32 , as opposed to an instantaneous transverse cut at a right angle to the machine direction movement of the web. 
     Referring once again to FIG. 1, anvil roll  32  has a plurality of peripherally-disposed apertures (not shown) that extend across and around the cylindrical outer surface of the roll. The apertures at predetermined portions of the anvil roll periphery are in communication with a source of vacuum (not shown) through a suitable vacuum manifold (not shown). The vacuum manifold can be placed in contact with an apertured end wall of anvil roll  32  to provide a communication path between the source of vacuum and the peripherally-distributed apertures. Apertured rolls having an apertured end wall and corresponding manifolds that provide pressurized air or vacuum to peripherally-distributed apertures in such a roll while it is rotating are known and will therefore not be further described herein. 
     Anvil roll  32  includes a holding zone  50  that extends over a predetermined peripheral area of the roll, such as the peripheral area subtended by the angle α, which can be 90° as shown in FIG.  1 . Angle α can be another angle than 90°, based upon the relative positions of anvil roll  32 , cutter roll  34 , and transfer roll  46 , to maintain cut sections  44  on the peripheral surface of anvil roll  32  after the second cut that defines the machine-direction length of cut section  44 , until the cut section is transferred to second web  14 . Holding zone  50  can be a high vacuum zone that serves to relatively tightly hold cut sections  44  to the surface of anvil roll  32  after the sections have been severed from first moving web  12 . Thus, rotating anvil roll  32  carries cut sections  44  from the nip defined between cutter roll  34  and anvil roll  32  to the nip defined between transfer roll  46  and anvil roll  32 . 
     A web slip zone  52  is provided on anvil roll  32  immediately upstream of holding zone  50 . Web slip zone  52  is defined by a predetermined peripheral area of anvil roll  32 , such as the peripheral area subtended by the angle θ, and provides a zone that is in communication with a source of low vacuum to lightly hold web  12  against the surface of anvil roll  32 . Web slip zone  52  allows the leading edge of web  12  to slip relative to the moving peripheral surface of anvil roll  32  at a time before a cut is made in the web. The angle θ defining web slip zone  52  can be an angle of approximately 30°, although that angle can be any desired angle and can be selected based upon the relative sizes and relative dispositions of the elements of the apparatus that are upstream of anvil roll  32 . 
     As will be more fully described hereinafter, the rotation of web deflector  24 , which rotates in the same direction as anvil roll  32  and at a constant angular speed, causes the speed of web  12 , as it leaves the web deflector, to undergo cyclic acceleration and deceleration, depending upon the angular position of web deflector  24  relative to anvil roll  32 . In the arrangement illustrated in FIG. 1, the diameter of imaginary circle  28  described by the radially-outermost surface of web deflector  24 , as the deflector is rotated about the axis of shaft  26 , is equal to the radius of anvil roll  32 , to enable two cuts at an appropriate spacing to be made in web  12  in order to provide a cut segment  44  having the desired machine-direction length. In that regard, the angle φ shown in FIG. 1 subtends an arc on web deflector  24  having a machine-direction length that corresponds with the machine-direction lengths of each of transversely-disposed cutting knives  40 ,  42  carried by cutter roll  34 . 
     The external peripheral configuration of web deflector  24  is shown in enlarged form in cross section in FIG.  3 . In the configuration as shown, the upper left portion of the deflector cross section includes a first constant radius zone  54  subtended by angle φ, which can range from about 2° to about 35°. The surface length of first constant radius zone  54  corresponds with the machine-direction-length component of a single cut to be made in web  12 . Thus, the peripheral distance along the surface of web deflector  24  defined by first contact zone  54  corresponds with the machine direction length of the cut to be made in web  12 . During the time that a cut is made in web  12 , the linear speed of that portion of the web that is in contact with anvil roll  32  matches the linear speed of the periphery of the anvil roll, so that the cut can be cleanly made. 
     Proceeding in a clockwise direction from first constant radius zone  54 , relative to the axis of rotation of the deflector, the next succeeding portion of the deflector surface is a curvilinear intermediate section that resembles a spiral or a volute and serves to define a web storage zone  56 . The storage zone subtends an angle that ranges from about 30° to about 220°. Incoming web  12  is progressively deflected away from the axis of rotation of web deflector  24  and away from anvil roll  32  by web storage zone  56  until a succeeding cut is intended to be made in web  12 . 
     After web storage zone  56 , there is provided a second constant radius zone  58  on web deflector  24 . Within second constant radius zone  58  the speed at which the web section is received matches the constant infeed speed of the upstream portion of web  12 . The second constant radius zone subtends an arc that is the same angle φ as that of the first constant radius zone. 
     Proceeding clockwise from second constant radius zone  58  and terminating at first constant radius zone  54  is a rectilinear intermediate section that defines a null zone  60  that subtends an angle that can range from about 45° to about 87°. Within null zone  60  the leading edge portion of web  12  decelerates, relative to the surface of anvil roll  32 , in preparation for the subsequent web storage and the ensuing next cut cycle. 
     The relative positions of the various elements of the apparatus shown in FIG. 1 during various portions of an operating cycle are shown progressively in FIGS. 4 through 11 for successive incremental increases in the degree of rotation of anvil roll  32 , cutter roll  34 , and web deflector  24 . In the positions of the respective components of the apparatus as they are shown in FIG. 4, several cut sections  44  have been transferred to continuously moving second web  14 . Additionally, the leading edge  62  of first web  12 , which is defined by the second cut that formed the trailing edge of the immediately preceding cut section  44 , has passed the twelve o&#39;clock position on anvil roll  32  as the forward portion of first web  12  travels at the same linear speed as the surface speed of the anvil roll. 
     In the positions shown in FIG. 4, the cutter is just beginning the second cut into the forward portion of first web  12  to form what will be the next cut section. During that time web deflector  24  is rotating to allow the forward portion of first web  12  to proceed at a linear speed that matches the peripheral surface speed of anvil roll  32 . As anvil roll  32  and cutter roll  34  continue to rotate through an angle of about 20°, web deflector  24  rotates through an angle twice that size, of about 40°, to the position shown in FIG.  5 . 
     In the relative positions of the several components of the apparatus as shown in FIG. 5, the second cut has been completed in first web  12  to form the next cut section  64 . The cut was effected during the time the forward portion of first web  12  moves at the same speed as the surface speed of the anvil roll. Cut section  64  is maintained on the peripheral surface of anvil roll  32  in holding zone  50  by the vacuum that is applied to an end wall of anvil roll  32 . At the completion of the second cut, web deflector  24  has rotated to a point at which the matching of the linear speeds of the forward portion of first web  12  and that of the periphery of anvil roll  32  terminates. 
     After a second cut is completed to define a complete cut section  44 , anvil roll  32  and cutter roll  34  each continue to rotate to the positions shown in FIG. 6, which are approximately 25° of rotation beyond their positions as shown in FIG.  5 . When the rolls are in the FIG. 6 position, cutting knife  40  has separated from associated anvil  36 , and cut section  64  has been retained in holding zone  50  of anvil roll  32  as the anvil roll surface revolves toward transfer roll  46 . In the meantime, web deflector  24  has continued its rotation as the leading edge of first web  12  has moved beyond the twelve o&#39;clock position relative to anvil roll  32  by virtue of the reduced outward deflection of web  12  by web deflector  24 . As also is apparent from FIG. 6, first web  12  begins to come into contact with web storage zone  56  of web deflector  24 . Additional rotation of web deflector  24  serves to cause the approaching portion of first web  12  to be pushed radially outwardly, relative to web deflector  24 , and in a direction away from anvil roll  32 , as is shown more clearly in the progressive views of FIGS. 7 through 10. 
     Referring now to FIGS. 7 and 8, cut segment  64  is carried by anvil roll  32  into the nip defined between anvil roll  32  and transfer roll  46 , to begin the gradual transfer of cut segment  64  from anvil roll  32  to the facing surface of second web  14 . During the time interval within which cut segment  64  is undergoing transfer to second web  14 , the speed of the new leading edge  66  at the forward portion of first web  12  diminishes and the forward portion of first web  12  slips relative to the peripheral surface of anvil roll  32  as the anvil roll continues to rotate at a constant rotational speed. The slippage occurs because of the progressively increasing radius of web deflector  24  within web storage zone  56 , which pushes the approaching portion of first web  12  in a direction away from anvil roll  32  as first web  12  continues its movement, resulting in new leading edge  66  at the forward portion of first web  12  being substantially stationary relative to the axis of rotation of anvil roll  32  as the anvil roll continues to rotate. The forward portion of first web  12  is lightly held against the moving peripheral surface of anvil roll  32  by a low vacuum level communicated to anvil roll  32  and applied at the roll surface at web slip zone  52 . During that time the downstream portion of first web  12  between web deflector  24  and anvil roll  32  is maintained at a constant angle relative to anvil roll  32  by virtue of guide bar  30 . 
     In FIG. 9 the respective components have continued their rotation and cut segment  64  has been completely transferred to second web  14 . At the same time, new leading edge  66  of first web  12  continues to slip on the peripheral surface of anvil roll  32  as additional first web material is, in essence, taken up or stored by the increasing radius of web deflector  24  as it rotates around its axis to the position shown in FIG.  10 . At that point the deflection of first web  12  away from anvil roll  32  has been completed, and first web  12  begins to come into contact with first constant radius zone  54  of web deflector  24 . 
     FIG. 11 shows the components after they have rotated through an additional increment. Anvil roll  32  and cutter roll  34  are shown in their respective positions shortly before a successive cut at the forward portion of first web  12  is commenced to define the next cut section. The forward portion of first web  12  continues to slip on the peripheral surface of anvil roll  32 , at a gradually diminishing relative speed, as cutting knife  42  carried by cutter roll  34  approaches anvil  38  carried by anvil roll  32 . New leading edge  66  of first web  12  begins to accelerate to a linear speed that matches the peripheral speed of anvil roll  32  until the components of the apparatus again reach their respective positions as shown in FIG. 4 to begin the next cutting cycle. 
     As will be appreciated, the disclosed apparatus permits a cut to be continuously made as the anvil roll rotates, so that the cut is made in a progressive manner, rather than instantaneously across the overlay material web, as in the prior art devices. Further, it will also be apparent that the respective rotating elements of the apparatus rotate continuously and at a constant speed, thereby avoiding the need for sudden decelerations and accelerations of the rolls, with the consequent stresses and increased wear that such operations engender. Moreover, the web deflector  24 , as shown in FIGS. 1-11, having a continuous outer surface, can be particularly adapted for use of the device in connection with web materials having a relatively moderate modulus of elasticity. Such web materials should be capable of accepting the tensile loads that are applied to the first moving web during the course of the rotational movement of web deflector  24  as it deflects first web  12  away from anvil roll  32  during the web take-up portion of the operating cycle, and without significant elongation. 
     The web deflector in accordance with the present invention is also adaptable for use in connection with web materials that have a relatively low modulus of elasticity. For example, relatively delicate webs of material, such as tissue, certain non-woven fibrous webs or other types of extensible materials, can also be utilized in an apparatus that includes a web deflector in accordance with the present invention. When such low modulus materials are utilized as the first web material it is desirable to reduce the level of surface friction between the first web material and the web deflector, to avoid excessive elongation of the web during the web-take-up phase of the operating cycle. Thus, it is desirable to minimize the surface-friction-induced tension applied to the first web to avoid permanent elongation of the web, which could result in cut segments having different or irregular cut lengths. 
     One way in which surface friction between the web deflector and first web  12  can be minimized is by providing a web deflector  67  as shown in FIG.  12 . Web deflector  67  has a peripheral surface that itself moves, and at substantially the same linear speed as that of the forwardmost portion of web  12  Such a moving web deflector surface can be provided by a driven, endless belt  68  that extends across the width of web deflector  67  and that defines the web deflector outer peripheral surface. The belt is driven to move at substantially the same linear speed as that of first web  12 , and it can be supported on a plurality of elongated rollers  70  through  74 . Rollers  70  through  74  can be driven by gears from drive shaft  26   a  or by a suitable belt drive system similar to that described hereinafter in connection with the roller drive system described hereinafter and shown in FIGS. 13 and 14. 
     As an alternative to the use of an endless moving belt to define the peripheral surface of the web deflector, a series of rotatable, elongated rollers can be provided. In that regard, the radially outermost peripheral edges of each of the rollers are respective points that define the cross-sectional shape of the periphery of web deflector  80  as shown in FIGS. 13 and 14. FIG. 13 is a view parallel to the machine axis taken through web deflector  80  that includes a plurality of rollers  82  through  90  that are each rotatably supported in bearings carried in a pair of spaced end housings  92 ,  94 . 
     A pair of spaced, parallel support bars  96 ,  98  extend between end housings  92 ,  94  to interconnect them and to provide a supporting framework for the respective rollers. Within each of end housings  92 ,  94 , driven rollers  84 ,  86 ,  88 , and  90  each include respective end-mounted drive pulleys  100 ,  102  that are secured to the outermost ends of the respective rollers, each of the drive pulleys having a groove or recess to receive a drive belt  104 . Belt  104  passes over the respective pulleys  100 ,  102  and is driven from pulleys  100 ,  102  carried on drive shaft  26   a  driven from a suitable power source (not shown) by a belt or the like that drives a main drive pulley  106 . The sizes of the respective pulleys are selected to provide a driven roller peripheral speed that causes the respective driven rollers to rotate at speeds such that their respective surface speeds correspond substantially with the linear speed of movement of first web  12 , thereby minimizing friction between the moving web and the deflector and avoiding undesired elongation of a delicate or easily extensible material web. And although shown and described as a belt drive, it will be apparent to those skilled in the art that other drive arrangement can also be utilized, such as a chain drive, a gear drive, or the like. 
     In addition to the belt approach shown in FIG.  12  and the driven roller approach shown in FIGS. 13 and 14, the friction between first web  12  and the surface of the web deflector can alternatively be minimized by providing a web deflector  108  that provides a peripheral air lubrication film, as shown in FIGS. 15 through 18. Deflector  108  can have a continuous outer peripheral surface  110  that is contacted by first web  12  and that includes a plurality of apertures  112  through which pressurized air can pass to form a thin film of air on outer surface  110  to minimize direct frictional contact between first web  12  and peripheral surface  110  of deflector  108 . 
     As best seen in FIG. 15, outer surface  110  of web deflector  108  is positioned between a pair of opposed end plates  114 ,  116 . Deflector  108  includes a series of longitudinally-extending air distributor passageways  118  that communicate with one or more longitudinally-extending rows each including a plurality of apertures  112  that extend radially through peripheral surface  110  of deflector  108 . End plates  114 ,  116  include a plurality of circularly-disposed, spaced openings  120  that communicate with respective ones of air distributors  118 . Positioned adjacent end plates  114 ,  116  are a pair of air manifolds  122 ,  124  that communicate with a source of pressurized air (not shown) through respective air inlet conduits  126 ,  128 . Web deflector  108  includes stub shafts  130  at each end that are rotatably carried in a respective end journal  132 . 
     Pressurized air is provided to air manifolds  122 ,  124  and flows into passageways  118  within the interior of web deflector  108 . The pressurized air exits through apertures  112  and thereby provides a peripheral air film that serves as an air bearing against which a fragile first web  12  can move to minimize friction between the web and the deflector surface and to minimize possible undesirable elongation of the low modulus first web material. 
     Although particular embodiments of the present invention have been illustrated and described, it would be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit of the present invention. It is therefore intended to be encompassed within the appended claims all such changes and modifications that fall within the scope of the present invention.

Technology Category: 4