Patent Publication Number: US-6988688-B2

Title: Web winding apparatus having traveling, gimbaled cinch roller and winding method

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   Reference is made to commonly assigned, co-pending U.S. patent application Ser. No. 10/460,552, entitled: WINDING APPARATUS HAVING BERNOULLI GUIDE CHUTE LEADING INTO ROLLER-CORE NIP AND METHOD, filed Jun. 12, 2003, in the name of Joseph A. Watkins et al. 
   FIELD OF THE INVENTION 
   The invention relates to equipment and methods for winding webs and more particularly relates to a film winder having a traveling, gimbaled cinch roller and winding method. 
   BACKGROUND OF THE INVENTION 
   Automated equipment has long been available to wind webs of photographic film, paper, and other materials tightly about cores. The web is commonly wound onto a core through a nip between the core or growing web roll and another roller. This helps wind the film tightly. The winding mechanisms include provisions allowing for growth of the web roll. U.S. Pat. No. 4,697,755 discloses a mechanism in which a core is pivoted as the size of the web roll changes. U.S. Pat. No. 3,712,554 discloses a winding mechanism in which a builder roller is pivoted. U.S. Pat. No. 5,256,232 translates a builder roller on a slidable carriage. The builder roller also pivots. This approach also has the advantage of allowing separate adjustment of tension on the web and pressure at the nip. This approach uses an idler roller to turn the web and direct the web onto the builder roller. 
   Prior to winding, the web is cinched onto the core. This can be done by inserting the free end of the web into a slot in the core, but this can lead to deformation or damage to the end of the web. This is undesirable in some uses, such as film cinematography, in which the free end of the film can have otherwise usable images. The cinching can be provided without the use of a slot or the like, by gripping the leading portion of the web prior to and during the winding of an initial turn. This adds complexity in that the elements used to initially grip the leading portion of the film cannot be left in positions that would interfere with the growing web roll. 
   U.S. Pat. No. 5,248,107 discloses a film winding apparatus, in which a core is supported on a pair of drums and is held in place by a rider roller. For cinching, a nip roller is brought into contact with the web to hold the web in position. The leading portion is then wrapped around the core by a wrapping table, a slide roller, and a wrapping roller. The wrapping table and slide roller are first moved vertically. The slide roller is then moved horizontally to push the web against the core. The wrapping roller is then brought toward the web to push the web against the core. The wrapping roller is then rolled circumferentially around 45 degrees of the core to wrap that part of the leading portion against the core. The nip roller, wrapping table, slide roller, and wrapping roller are all moved to their original positions after cinching. This approach uses many parts and moves those parts in a complex manner. 
   U.S. Pat. Nos. 2,989,265 and 5,690,264 disclose apparatus having center pivoted web rollers. 
   It would thus be desirable to provide improved winding apparatus and methods that cinch with little or no damage to the free end of the web, in a way that is comparable with a carriage mounted builder roller. 
   SUMMARY OF THE INVENTION 
   The invention is defined by the claims. The invention, in broader aspects, provides winding methods and apparatus. In the methods, a primary nip is formed against a web. The primary nip defines continuing and leading portions of the web. A secondary nip is formed against and moved along the leading portion, from an outfeed side of the primary nip to an infeed side. The continuing portion and a free end of the leading portion are then simultaneously advanced into the primary nip. Winding apparatus has a winding spindle and builder roller that rotate about parallel winding and builder roller axes, respectively. An axle defines a guide axis and carries a cinch roller that rotates about the guide axis. The axle pivots between first and second orientations, in which the guide axis parallels and is transverse to the winding axis, respectively. The axle moves in the first orientation, in an incomplete orbit about the winding spindle from a start to a rotated position, both adjacent the builder roller, and returns in the second orientation. 
   It is an advantageous effect of the invention that improved winding apparatus and methods are provided that cinch with little or no damage to the free end of the web, in a way that is comparable with a carriage mounted builder roller. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above-mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying figures wherein: 
       FIG. 1  is a front perspective view of an embodiment of the winding apparatus. Components are in position for cinching, but the web is not shown. The carriage and builder roller are in the forward position. The carrier is in the rotated position. The guide assembly is in the first orientation. 
       FIG. 2  is a front view of a modification of the apparatus of  FIG. 1 . The modification is the additional of a functional unit between the unwind web roll and one of the secondary rollers. The apparatus is shown during cinching. Arrows indicate the directions of rotation of the spindles. 
       FIG. 3  is a front view of another embodiment of the apparatus. Arrows indicate directions of rotation of the spindles. The apparatus is shown during cinching. 
       FIG. 4  is the same view as  FIG. 1 , but the web is shown and the apparatus is shown following cutting of the web. In this and some of the other drawings, the cover is illustrated as a rectangular box. The location of the free end of the web within the cutter is indicated by dashed lines. The carriage and builder roller are in the standby position. The builder roller is biased against the stop. The carrier and guide assembly are in the start position. The guide assembly is in the second orientation. ( FIGS. 4–21  are presented in sequential order, except as indicated.) 
       FIG. 5  is a partial enlargement of the view of  FIG. 4 . 
       FIG. 6  is the same view as  FIG. 5 , but the apparatus is shown following the completion of threading. The carriage and builder roller are in the standby position. The carrier and guide assembly are in the start position. The guide assembly is in the second orientation. 
       FIG. 7  is a partial front view of the apparatus as shown in  FIG. 6 . 
       FIG. 8  is the same view as  FIG. 5 , but the apparatus is shown following the translation of the carriage and builder roller to the forward position. The builder roller is biased against the web and winding core. The carrier and guide assembly are in the start position. The guide assembly is in the second orientation. 
       FIG. 9  is a partial front view of the apparatus as shown in  FIG. 8 . 
       FIG. 10  is the same view as  FIG. 5 , but the guide assembly is pivoted to the first orientation, in which the cinch roller and winding core define the secondary nip. The carrier and guide assembly remain in the start position. 
       FIG. 11  is a partial enlargement of the view of  FIG. 10 . 
       FIG. 12  is a partial front view of the apparatus as shown in  FIG. 10 . 
       FIG. 13  is the same view as  FIG. 5 , but following the traveling of the secondary nip in an incomplete orbit around the winding core. The guide assembly remains in the first orientation. The carrier and guide assembly are in the rotated position. 
       FIG. 14  is a partial enlargement of the view of  FIG. 13 . 
       FIG. 15  is a partial front view of the apparatus as shown in  FIG. 13 . 
       FIG. 16  is substantially the same view as  FIG. 11 , but following the completion of cinching. The guide assembly is in the second orientation. The carrier and guide assembly are in the rotated position. 
       FIG. 17  is a partial front view of the apparatus as shown in  FIG. 16 . 
       FIG. 18  is the same view as  FIG. 11 , but during winding. The carrier is in the start position. The guide assembly is in the second orientation. 
       FIG. 19  is the same view as  FIG. 17 , but following the completion of winding and before web cut off. 
       FIG. 20  is the same view as  FIG. 10 , but following completion of winding, cut off of the web, and withdrawal of the carriage and builder roller to the standby position. 
       FIG. 21  is the same view as  FIG. 17 , but following the removal of the completed web roll. 
       FIG. 22  is a perspective view of the builder drive of the apparatus of  FIG. 1 . 
       FIG. 23  is a front view of the forward end of the builder roller assembly of the apparatus of  FIG. 1 , showing the carriage and builder roller in the forward position. 
       FIG. 24  is a rear, perspective view of the forward end of the builder roller assembly of  FIG. 23 . 
       FIG. 25  is a perspective view of the cincher assembly of the apparatus of  FIG. 1 . The guide assembly as shown in the first orientation. 
       FIG. 26  is a partial, rotated, rear perspective view of the cincher assembly of  FIG. 25 . 
       FIG. 27  is a perspective view of the second link of the linkage of the cincher assembly of  FIG. 26 . 
       FIG. 28  is a perspective view of the yoke of the cincher assembly of  FIG. 25 . 
       FIG. 29  is a cutaway view of the cinch roller and axle of the cincher assembly of  FIG. 25 . 
       FIG. 30  is a perspective view of the collar of the cincher assembly of  FIG. 25 . 
       FIGS. 31–33  are diagrammatical front views illustrating the operation of the builder roller of the apparatus of  FIG. 1  during winding in a contact (pressure bearing) mode. 
       FIGS. 34–36  are diagrammatical front views illustrating the operation of the builder roller of the apparatus of  FIG. 1  in a no contact (pressure free) mode. 
       FIG. 37  is a schematic diagram of the control system of the apparatus of  FIG. 1 . 
       FIG. 38  is a partial top view of the builder roller assembly of  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The term “web” is used herein to refer to a thin membrane of photographic film, coated or uncoated paper or plastic, or other material. The web has a uniform transverse dimension, within limits required for a particular use. The length of the web is determinate or indeterminate, as appropriate for a particular use. For example, the web can be a short sheet of known length or a long roll that is cut to a particular length, as needed. 
   The term “rotary element” is used herein to refer to a rotating structure that is capable of receiving the web in a single turn or portion of a turn, or in a wrap or coil having multiple turns. For example, the “rotary element” can be a roller, a mandrel, or a core or spool that can be removably mounted on a spindle. The invention is generally discussed herein in terms of embodiments in which the rotating element is a core that is mounted on a spindle. 
   The term “fixed” and like terms are used herein in the sense of an immobile rather than movable mounting. 
   Referring initially to  FIGS. 1–2 , the winding apparatus  10  has a base  12  to which other components are attached. The base  12  is illustrated in the figures as a vertically aligned panel, but this is not critical. For example, the base  12  can be aligned horizontally or an assembly of smaller members (not illustrated) can be used instead of the panel. In the illustrated embodiments, features of the apparatus  10  that contact a web  14  are arranged on the front side of the base  12 . This is a matter of convenience and can be changed to meet particular requirements. The invention is described in relation to and is particularly advantageous for the winding of photographic film. Webs of other materials can be wound in a like manner. 
   A winding spindle  16  is mounted to the base  12 . The winding spindle  16  defines a core space (indicated by arrow  18  in  FIG. 21 ) that receives a core  20 , when a core  20  is mounted on the winding spindle  16 . The spindle  16  is configured to hold and turn the core  20  without slippage. Features for this purpose, such as square spindles  16 , 24  and matching core openings, are well known to those of skill in the art. In the illustrated embodiment, the spindle  16  has a protrusion that extends radially outward and is complementary to a pocket on the winding core. The cores  20  shown in the figures have a slot that can receive the free end of the web. This slot is present in conventional cores, but is not used in this invention. 
   A web supply  22  is mounted to the base  12  in spaced relation to the winding spindle  16 . The configuration of the web supply  22  is not critical. In the winding apparatus  10  shown in  FIG. 1 , the web supply  22  has an unwinding spindle  24  and a web roll  26  that is wound around an unwind core  20  that is mounted on the unwinding spindle  24 . Other configurations of web, such as a bin of bifolded web, can be used instead, depending upon web materials and other factors. 
   Additional components can also be provided as a part of the web supply  22 . For example, components such as idler rollers, tensioners, and cutters, can be provided. Referring to  FIGS. 1–2 , a series of secondary rollers  28  are located between the spindles  16 , 24 . One is above an imaginary line (not shown) connecting the spindles  16 , 24 . Two are below that line. (The terms “above”, “below”, “under”, and other directional terms used herein, are intended to aid in understanding of the drawings, but are otherwise arbitrary and are not intended to refer to absolute directions.) 
   A cutter  30  is located between two of the secondary rollers  28 . The cutter  30  can be any of the mechanisms known to those of skill in the art for cutting webs. The web  14  extends through the cutter  30 , as shown in  FIG. 2 , between a knife  32  and a platen  34 . The knife  32  is pushed against the platen  34  to cut the web  14 . The apparatus  10  is not limited to a web supply  22  having this particular arrangement. For example, more or less secondary rollers  28  can be provided, one or more secondary rollers  28  can be replaced by a fixed (immobile) guide (not shown) and one or more belts (powered or unpowered) can be used instead of or in addition to one or more of the secondary rollers  28 . 
   The apparatus  10  can be limited to the function of rewinding film; however, other functions can also be provided. Such functions are illustrated diagrammatically in  FIG. 2  by a function unit  36  in the shape of a box. Examples of function units include components for: digital scanning, optical projection, chemical processing, coating, laminating, and printing. 
   In the following, the cores  20  positioned on the winding spindle  16  and the unwinding spindle  24  are both the same; however, for convenience in the following discussion, the core  20  on the winding spindle  16  is sometimes referred to as the “winding core  20   a ” and the core  20  on the unwinding spindle  24  is sometimes referred to as the “unwind core  20   b”.    
   The winding spindle  16  rotates about a winding axis  38 . This rotation is powered by a web drive  40 . Additional components such as the unwinding spindle  24  can also be driven by the web drive  40 . The web drive includes one or more motors and can optionally include a gear train or trains, belt or belts, or other transmission (not shown). In the illustrated embodiment, the winding spindle  16  and unwinding spindle  24  are each directly driven by a separate electric motor  42  and the secondary rollers  28  are all idlers. 
   Referring now to  FIG. 37 , a control system  43  of the apparatus  10  includes a microprocessor or other controller  44  that is connected to the motors  42  and other controlled components by signal lines  46 . Features and operation of suitable controllers for this purpose are well known to those of skill in the art. Operations can also be sequenced manually using switches. 
   Between the unwinding spindle  24  and winding spindle  16  is a builder roller assembly  48 . The builder roller assembly  48  includes a builder roller  50 , which is supported on an arm  52  that is joined to a carriage  54 . The builder roller  50  can be an idler, that is, unpowered; or can be driven. It is currently preferred, for simplicity, that the builder roller  50  not be driven. In the embodiments disclosed herein, the builder roller  50  has a pair of opposed builder roller flanges  56 . (See  FIG. 24 .) 
   Referring to  FIGS. 1 ,  22 – 24 , and  38 , the carriage  54  is movable toward and away from the winding spindle  16  by a builder drive  58 . In illustrated embodiments, the builder drive  58  is a linear positioner having a servomotor  60  that drives a lead screw  62 . The carriage  54  is translated by the lead screw  62 . The builder roller assembly  48  has a track  64  that is aligned with the winding spindle  16 . The carriage  54  has a main member  66  that rides rectilinearly on the track  64  when the lead screw  62  is turned. Other types of builder drives can be used, but a linear positioner is currently preferred. 
   In the embodiment shown, the arm  52  is pivotably joined to the carriage  54  and the carriage  54  has a support member  68  that is fixed to the main member  66 . (The term “fixed” and like terms are used herein in the sense of joined in immobile relation to another part.) The support member  68  has a shaft  70  that is freely pivotable relative to the support member  68 . The arm  52  is fixed to and pivots with the shaft  70 . 
   The arm  52  is biased toward the winding spindle  16  by a biaser  72 . Various types of biasers, such as air springs and torsion rods, can be used. In the illustrated embodiments, the biaser  72  is a coil spring that is coiled around the support member  68 . A first end  74  of the spring  72  is held by an adjustment nut  76  (shown in  FIG. 38 ) that is screwed on the end of the support member  68 . A second end  75  of the spring  72  is held by the arm  52 . The adjustment nut  76  can be rotated to adjust the spring force. 
   Referring now to  FIGS. 1–21  and  25 – 30 , a cincher assembly  78  adjoins the winding spindle  16 . The cincher assembly  78  includes a mount  80  that is fixed to the base  12 , a carrier  82  that is joined to the mount  80  and a cinch roller  84  that is joined to the carrier  82 . The cinch roller  84  is movable, with the carrier  82 , in an incomplete orbit about the winding core  20   a  and winding spindle  16 . 
   In the illustrated embodiment, a sprocket support  86  is joined to the mount  80  at an outer end. A sprocket  88  is held between the sprocket support  86  and mount  80 . The sprocket  88  is rotatable by a sprocket drive  90  about a sprocket axis  92  that is parallel to the winding axis  38  defined by the winding spindle  16 . (See  FIG. 6 .) 
   A ring bearing  94  has first and second rings  96 , 98  that are freely movable relative to each other. The first ring  96  is fixed to the inner end of the mount  80 . The first ring  96  is aligned with the sprocket  88 . The second ring  98  is fixed to a ring gear  100  and a collar  101 . The ring gear  100  and ring bearing  94  are coaxial with the winding axis  38 . An endless belt  102  extends between the sprocket  88  and the ring gear  100 . Shock absorbers  104  optionally provided on the mount  80  or sprocket support  86  damp vibration of the sprocket  88  and belt  102 , during stopping. 
   The carrier  82  is movable with the collar  101 . The carrier  82  has a holder plate  106  that is a fixed to extensions  108  of the collar  101 . The extensions  108  axially space the holder plate  106  outward from the mount  80 . The holder plate  106  is roughly Y-shaped and has a pair of ears  110  that are joined to the extensions  108  of the collar  101 . A guide assembly  112  is mounted to the holder plate  106 . The guide assembly  112  is rotatable about the winding axis  38  along with the carrier  82 , collar  101 , ring gear  100 , and second ring  98 . 
   The guide assembly  112  has a yoke  114  having a pair of opposed fingers  116 . (See  FIG. 28 .) Each of the fingers  116  is pivotably joined to a respective ear  110  of the holder plate  106 . The guide assembly  112  is pivotable relative to the holder plate  106  about a pivot axis  118 . (See  FIG. 25 .) 
   An axle  120  is mounted to and extends outward from the yoke  114 . The axle  120  defines a guide axis  122 . The cinch roller  84  is mounted to the outer end  124  of the axle  120 . The cinch roller  84  has a pair of opposed cinch roller flanges  126 . 
   It is preferred that the cinch roller is gimbaled to the axle  120 . It is further preferred that the cinch roller  84  is gimbaled to the axle  120  at the longitudinal center of the cinch roller  84 . In the illustrated embodiments, the cinch roller  84  is gimbaled to the axle  120  midway between the cinch roller flanges  126 , by a gimbal bearing  128 . (See  FIG. 29 .) The gimbal bearing  128  allows the cinch roller  84  to freely pivot back and forth, into and out of alignment with the guide axis  122 . In the illustrated embodiment, the gimbaling is over a total range of about six degrees. 
   An actuator  130  is operatively connected to the yoke  114  of the guide assembly  112 , directly or by a linkage or other mechanical coupling. The actuator  130  can be a servomotor or pneumatic drive element or the like. The actuator  130  moves the guide assembly  112  between a first orientation and a second orientation. In the first orientation, the axle  120  of the guide assembly  112  is disposed parallel to the winding axis  38 . (See, for example,  FIG. 11 .) In the second orientation, the axle  120  of the guide assembly  112  is transverse to the winding axis  38 . (See, for example,  FIG. 16 .) In the illustrated embodiment, the guide assembly  112  is disposed within the opening between the ears  110  of the holder plate  106  and the guide assembly  112  is at least roughly radial to the winding axis  38 , in the second orientation and the cinch roller  84  and axle  120  extend outward from the holder plate  106 , in the first orientation. 
   In the illustrated embodiment, the yoke  114  has a post  132  that extends outward through one of the ears  110  of the holder plate  106 . A linkage  134  couples the post  132  to the actuator  130 , in this case to the piston of an air cylinder that is connected to a compressed air source  133  (shown in  FIG. 37 ) by a line  135  (illustrated in  FIG. 37  as a flexible hose). The linkage  134  has a first link  136  that is rigidly attached to the post  132 . A second link  138  is pivotably joined to the first link  136  and extends outward to the actuator  130 . The second link  138  optionally has a leg  140  that extends out to a shock absorber  142  to damp movement of the yoke  114  during use. The air cylinder or other actuator  130  can be pivotably mounted, as shown in  FIG. 26 , to provide a slight free play in the linkage  134  and, thus, reduce a risk of binding. 
   Operation of the apparatus  10  can be controlled manually, or by mechanic logic, that is, mechanical connections that coordinate operation of the various features. The apparatus  10  can also be controlled by a microprocessor or other electronic controller  44 , as illustrated in  FIG. 37 . Sensors can be provided as needed to detect web  14  movement, rotation of components, or other operational parameters. In the illustrated embodiments, an encoder  144  is shown attached to one of the secondary rollers  28 . Communication lines operatively connect the controller  44  to controlled drives, sensors, and other features. 
   In some uses, it may be desirable to add additional components to the apparatus  10 . An example of such a component is a web tensioner (not shown). Features and use of web tensioners, guides, and other such components are well known to those of skilled in the art. 
   Apparatus  10  can be changed in other ways to meet the requirements of a particular use. In the embodiment of the apparatus  10  above described, the web  14  is taken off the bottom of the unwind web roll  26  and the spindles  16 , 24  rotate in the directions indicated by arrows  146  and  148 . The outer surface of the web  14  of the unwind web roll  26  becomes the outer surface of the web  14  of the wind web roll  26 . (See  FIG. 2 .) In an alternative embodiment shown in  FIG. 3 , the direction of rotation of the unwinding spindle  24  is reversed, as indicated by arrow  149 , and the web  14  is taken off the top rather than the bottom of the unwind web roll  26 . In this case, the web  14  is turned over during the winding process. 
   Referring now to  FIGS. 4–21 , in the winding methods, a web roll  26  is placed on the unwinding spindle  24 . The web roll  26  has a core  20   a  and a roll of web  14  wrapped around the core  20   a . An empty core  20  (the winding core  20   a ) is placed on the winding spindle  16 . 
   A starter segment  150  of the web  14  is next unwound. The starter segment  150  of the web  14  includes a leading portion  152  that has a free end  154  and a threading portion  156  that connects the leading portion  152  to the remainder  158  of the unwind web roll  26 . (See  FIG. 4 .) During cinching, the leading portion  152  of the web  14  is wrapped around the winding core  20   a . It is highly preferred that this leading portion  152  of the web  14  has a length that accurately and precisely matches a predetermined value within a predetermined tolerance. This can be easily achieved by unwinding a starter segment  150  from the unwind web roll  26  that is only as long as is needed for threading and for the leading portion  152 . This can be done manually by measuring the starter segment  150 , but is more easily done using a driven unwinding spindle  24 , a controller, and an encoder or other sensor that measures the length of the web that is supplied. 
   In the illustrated embodiment, the web  14  is threaded from the unwind web roll  26 , over two of the secondary rollers  28 , and through the cutter  30 . This initial threading of the web  14  can be performed manually or using automated equipment, in a manner known to those of skill in the art. The knife  32  of the cutter  30  cuts the web  14  to provide an initial datum. (See  FIGS. 4–5 .) The controller  44  then advances the web  14  by a predetermined length to provide a starter segment  150  having required threading and leading portions  156 , 152 . (See  FIGS. 6–7 .) 
   In the illustrated embodiments, the length of the threading and leading portions  156 , 152  remains constant. This is not the case if the required web portions have variable lengths due to the action of a web tensioner or other component that can alter the path of the web  14  from the web roll  26 . In this case, the required length for the starter segment  150  needs to be monitored manually or by use of sensors, and adjustments provided as needed. 
   After the starter segment  150  has been advanced, the starter segment  150  is threaded under the right lower secondary roller  28 , and back up to the builder roller  50 . The starter segment  150  is then draped over the top of the builder roller  50 . (See  FIGS. 6–7 .) This continued threading and draping of the web  14  can be performed manually (as required in the illustrated embodiments) or automatically using a pick and place device or the like. Threading and draping can occur concurrent with the advancing of the starter segment  150  or following advancing, with the web  14  stopped. 
   After the draping of the starter segment  150  over the builder roller  50 , the carriage  54  is translated toward the winding core  20   a  from a standby position to a forward position. In the standby position, the builder roller  50  is spaced away from the winding spindle  16 . (See  FIGS. 6–7 .) In the forward position, a primary nip  160  is formed between the builder roller  50  and the winding core  20   a . (See  FIGS. 8–9 .) The primary nip  160  has a long dimension that is parallel to the winding axis  38 . In moving to the forward position, the builder roller  50  deflects the web  14  against the winding core  20   a , thus the primary nip  160  is occupied by the web  14 . 
   The primary nip  160  has an infeed side  162  and an outfeed side  164 . (See  FIG. 9 .) In the figures, the infeed side  162  is above the outfeed side  164 . The leading portion  152  of the web  14  extends from the outfeed side  164  of the primary nip  160  to the free end  154 . The rest of the web  14 , also referred to herein as the continuing portion  166 , extends from the infeed side  162  of the primary nip  160  to the unwind web roll  26 . 
   When the carriage  54  is translating from the standby position to the forward position, the guide assembly  112  is in the second orientation. After the builder roller assembly  48  reaches the forward position and the builder roller  50  and winding core  20   a  have formed the primary nip  160 , the guide assembly  112  is pivoted relative to the holder plate  106  into the first orientation. During this pivoting, the cinch roller  84  comes into contact with the leading portion  152  of the web  14  and then pushes the leading portion  152  against the winding core  20   a . The position of the leading portion  152  at this time may be as shown in  FIGS. 8–12 , or may be inclined or curled toward or away from the builder roller  50 . This is not a problem unless the guide assembly  112  could catch against and misdirect the leading portion  152  during pivoting. This can be compensated for by manual movement of the leading portion  152  by the operator or by addition of one or more guides (not shown) to direct the leading portion  152  toward one of the positions shown in  FIGS. 8–12 . 
   When the guide assembly  112  is in the first orientation, the cinch roller  84  and the winding core  20   a  together define a secondary nip  168 . (See  FIGS. 10–12 .) The secondary nip  168  has a long dimension that is parallel to and spaced from the primary nip  160 . The secondary nip  168 , like the primary nip  160 , is occupied by the web  14 . 
   If the apparatus  10  is to be used for winding photographic film, then it is preferred that the film be contacted in the primary and secondary nips  160 , 168  only at opposed lateral margins of the film. This prevents pressure marking in image areas of the film, since the film is not contacted between the lateral margins. In this case, each nip  160 , 168  can be considered to have two spaced apart segments separated by an enlarged gap in which the web  14  is not squeezed. In other embodiments, the nips are continuous from side to side and can continuously contact the web between lateral margins of the web. 
   When the secondary nip  168  is first formed, the cinch roller  84  is in a start position at the outfeed side  164  of the primary nip  160 , in an approximately 8 o&#39;clock position relative to the winding axis  38 . (See  FIGS. 10–12 .) The guide assembly  112  is next moved in an incomplete orbit about the winding axis  38  and winding spindle  16 , to a rotated position at the infeed side  162  of the primary nip  160 , in an approximately 10 o&#39;clock position. (See  FIGS. 13–15 .) The arc of the incomplete orbit is greater than 180 degrees. It is currently preferred that the guide assembly  112  be rotated through 270 degrees or more. The rotation of the guide assembly  112  is accompanied by rotation of the carrier  82 , collar  101 , ring gear  100 , and second ring  98  through the same arc. 
   During rotation of the cinch roller  84  about the winding core  20   a , the secondary nip  168  travels along the leading portion  152  of the web  14  and most of the way around the winding core  20   a . This travel of the secondary nip  168  bends the leading portion  152  of the web  14  into a loop and presses the leading portion  152  against the winding core  20   a.    
   In the illustrated embodiments, the leading portion  152  of the web  14  is smoothed onto the winding core  20   a , with little or no deleterious contact, such as scuffing, stretching, or bunching. Several features of the illustrated embodiments provide this result. 
   In the illustrated embodiments, the primary nip  160  is formed before the formation of the secondary nip  168 . This approach, in combination with the close positioning of the two nips  160 , 168  when the secondary nip  168  is initially formed, tends to minimize slack in the web  14  between the two nips  160 , 168 . Slack is undesirable, because, during travel of the secondary nip  168 , the cinch roller  84  would tend to pull the slack portion against the winding core  20   a  leading to possible damage. 
   In the illustrated embodiments, during the travel of the secondary nip  168 , the linear velocity of the leading portion  152  of the web  14  relative to the winding core  20   a  is at or near zero at the secondary nip  168 . This prevents differential movement of the leading portion  152  relative to the winding core  20   a , which could lead to damage to the leading portion  152 . The zero relative linear velocity of the winding core  20   a  and leading portion  152  is achieved by holding both web advance and winding core  20   a  rotation stopped, while the cinch roller  84  travels from the start position at the outfeed side  164  of the primary nip  160  to the rotated position at the infeed side  162  of the primary nip  160 . Web advance can be stopped at the web supply  22 , but it is preferred that web advance is stopped at or near the primary nip  160 . 
   The web advance can be stopped by pinching the web  14  between the builder roller  50  and the winding core  20   a . During the translational movement of the builder roller assembly  48 , the builder roller  50  is pushed firmly toward the winding core  20   a  until the web  14  is pinched. The web  14  remains pinched while the guide assembly  112  is rotated about the winding core  20   a . The force applied by the builder roller  50  against the pinched web  14  provides for a static friction that overcomes the pulling force applied by the action of the cinch roller  84  on the web  14  and winding core  20   a . The force applied by the builder roller  50  is, preferably, minimized to reduce the risk of damage to the web  14 . A separate brake (not shown) can alternatively or additionally be used for stopping web  14  movement, but use of the builder roller  50  alone is simpler. 
   In the illustrated embodiments, the linear velocity of the cinch roller  84  at the secondary nip  168  is the same or about the same as the linear velocity of the travel of the secondary nip  168  along the leading portion  152 . This prevents differential movement of the leading portion  152  relative to the cinch roller  84 , which could lead to damage to the leading portion  152 . Like linear velocities of the revolving cinch roller  84  and the leading portion  152 , are achieved by allowing the cinch roller  84  to freely revolve about the guide axis  122 , relative to the axle  120 , while holding the leading portion  152  and winding core  20   a  stopped. The free revolving of the cinch roller  84  also reduces friction against the leading portion  152  at the secondary nip  168 . Alternatively, the cinch roller  84  can be powered, but this is adds complexity, since synchronization of the revolving about the guide axis  122  and rotation about the rotation axis is needed to prevent distortions of the web  14 , such as scuffing, stretching, or bunching. 
   The leading portion  152  of the web  14  has a length that is less than the circumference of the winding core  20   a . The leading portion  152  is long enough to extend from the primary nip  160  to the secondary nip  168  and, preferably, is long enough to extend beyond the secondary nip  168 . The length and rotated position of the guide assembly  112  can be adjusted to accommodate curl or stiffness of the leading portion  152  that would tend to direct the free end  154  of the leading portion  152  away from the primary nip  160 . 
   After the cinch roller  84  reaches the rotated position, the winding spindle  16  is rotated, which causes the winding core  20   a  and builder roller  50  to rotate in opposite directions of rotation, as indicated by arrows  170  and  172  in  FIG. 13 . This simultaneously advances the free end  154  of the leading portion  152  and the continuing portion  166  of the web  14  into the primary nip  160 . At this time, the builder roller  50  can be in the same position, as that in which, the web  14  was initially pinched. Alternatively, the builder roller  50  can be retracted slightly to enlarge the primary nip  160  and reduce contact with the web  14  during further winding. 
   The rotation of the winding spindle  16  is continued until a plurality of turns of web  14  are wrapped over the leading portion  152 . The leading portion  152  cinches to the winding core  20   a  after a turn or two. 
   The gimbaling of the cinch roller  84  to the axle allows the cinch roller  84  to pivot back and forth relative to the guide axis  122  while the leading portion  152  of the web  14  is bent against the winding core  20   a . This accommodates nonuniformity in the cross-section of the winding core  20   a  and, more importantly, allows the cinch roller  84  to pivot during the winding of the first few turns of web  14 . This pivoting of the cinch roller  84  at the gimbal allows the cinch roller  84  to remain parallel to the web  14  at the secondary nip  168 , while the first few turns of web  14  are wrapped around the winding core  20   a . If a non-gimbaled cinch roller  84  is used, then pressure on one side of the growing web roll  26  increases as the web  14  is wound, due to the change in diameter causes by the turns of web  14 . With some web  14  materials, this is unimportant, but with film, there is a risk of pressure marking if a non-gimbaled cinch roller  84  is used. 
   At some time after cinching, the guide assembly  112  is pivoted back from the first orientation into the second orientation. (See  FIGS. 16–17 .) This eliminates the secondary nip  168 . The carrier  82  is pivoted back to the start position, during and/or after pivoting of the guide assembly  112  into the second orientation. (See  FIGS. 18–19 ) Winding is continued until a desired web roll  26  has been wound. The web  14  is then cut using the cutter  30  and the completed web roll  26  is removed. (See  FIGS. 19–20 .) 
   If the web roll  26  is large, then the builder roller assembly  48  is backed away from the winding axis  38  during winding. The builder roller assembly  48  begins winding in the forward position, and is then moved through a sequence of intermediate winding positions until the web roll  26  is completed. 
   Referring now particularly to  FIGS. 31–33 , in particular embodiments the biaser  72  is a constant-force coil spring. The coil spring  72  applies a biasing force that varies little over the range of movement of the arm  52 . The variation in force is preferably less than 5 percent and more preferably 2 percent or less. The constant-force spring allows the builder roller  50  to apply a substantially constant force at the primary nip  160  throughout winding. The force applied by the builder roller  50  remains constant even as the tension on the web  14  changes as the web roll  26  grows. 
   As long as the builder roller  50  remains in contact with the web  14  at the primary nip  160  and the arm  52  is pivoted within a range of constant force for the spring, then the force applied by the builder roller  50  is also decoupled from the position of the builder roller assembly  48  relative to the winding axis  38 . This allows the translational movement of the builder roller assembly  48  during winding to be standardized based upon the rate of web growth at a particular winding rate. This also allows builder roller  50  tension to be quickly and easily optimized for a particular web material and other winding conditions, since builder roller position during winding does not need to be considered. 
   Referring now particularly to  FIGS. 34–36 , in a particular embodiment, the builder roller assembly  48  is backed away from the winding axis  38  during winding, to the extent that the builder roller  50  no longer contacts the web roll  26 . The spring causes the arm  52  to pivot until a stop nut  176  on the arm  52  reaches a stop  174 , which is fixed to the carriage  54 . In this case, the builder roller assembly  48  is moved during winding based upon a rate of web roll  26  growth, so as to maintain a desired spacing between the builder roller  50  and the web roll  26 . 
   Features of the invention can be varied to meet particular requirements. For example, it may be convenient to eliminate flanges on the builder roller  50  and cinch roller  84 , if the winding core  20   a  is flanged. Likewise, the apparatus  10  can be modified to utilize the builder roller to dispense a liquid or powdered material onto the web  14  or otherwise treat the web  14 . For example, the builder roller can emboss or can apply an overcoat or adhesive layer or inked pattern (using a patterned builder roller). 
   The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.