Duplex web roll winding and splicing apparatus

An apparatus and method of winding a continuously moving web, and for splicing and transferring the web from a first core to a second core with no-fold-back or wrinkling of the web material during the splice. The web is fed through a first nip point and thereby applied to a lay-on roll, the lay-on roll further applying the web material onto first and second cores alternatively. An electrostatic charging bar positioned downstream from the nip point emits an electrostatic charge onto the web to temporarily adhere the web to the lay-on roll. A rotatable cutting knife cooperatively engageable with the lay-on roll cuts the web at a point downstream from the electrostatic charging bar but upstream from the first and second cores to produce a tail and new leading edge. The tail continues to be wound about the first roll, and the new leading edge is affixed to the second roll and the web is thereafter wound about the second core. The first and second cores are each independently movable toward and away from the lay-on roll so the web may be spliced and transferred from the first core to the second core, and alternatively from the second core to the first core.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates to a duplex web roll winding and splicing
 apparatus for continuously winding a moving web and also for splicing and
 transferring the web to a new core without stopping movement of the web.
 In particular, this invention relates to an apparatus and method for
 continuously winding and splicing a moving web onto a successive series of
 cores without causing a fold-back or wrinkling of the web.
 2. Background of the Related Art
 Many commercial and industrial laminating, coating and film processing
 operations are conducted on high speed web handling equipment which
 operate continuously for long periods of time. Paper converting is one
 example of such an operation. Numerous kinds of plastic film and thin
 foils are also processed in this manner. At the end of the processing line
 the web is wound lengthwise into a large roll of material commonly
 referred to in the trade as a parent roll, mill roll or finish roll. In
 the processing of web materials, it is inefficient to stop the entire
 operation each time an individual roll of material needs to be changed.
 For this reason, various types of winding and rewinding devices have been
 developed for cutting and transferring a moving web onto a new core so
 that successive rolls of material may be continuously wound without
 interrupting the web processing operation.
 One such rewind device, commonly referred to in the trade as either a
 turnover rewind stand or turret rewinder, is disclosed in U.S. Pat. No.
 3,529,785. A turnover rewind stand is comprised of a pair of rotatable
 spindles or cores mounted on opposite ends of a turret. During normal
 operation, one core is positioned close to the web processing line for
 rewinding the web, while the other core on the opposite end of the turret
 is positioned away from the web processing line. By revolving or "turning
 over" the turret, the spindle containing a fully wound roll of web
 material is moved away from the rewinding position and a new core is
 simultaneously moved into the rewinding position. The splice is
 accomplished by placing the moving web into contact with the new core,
 which is covered with an adhesive, and then severing the web with a knife
 at a point which is normally downstream from the new core. The web sticks
 to the new core and thereafter the web is rewound onto the new core. The
 finished roll, which is now positioned away from the processing line, may
 be removed and another new core put in its place. This process, referred
 to in the trade as splicing the web "on the fly," may be repeated over and
 over in order to rewind a number of rolls successively for as long as the
 web processing line is in operation.
 The splicing step described above involves cutting the web at a point which
 is downstream from the new core, which causes a portion of the web to
 fold-back on itself on the new core when the splice is performed. This
 fold-back results in a double thickness of the web and wrinkling of the
 web at the core which is undesirable. While the affects of the fold-back
 may be alleviated after a number of revolutions on the new core, the
 fold-back nonetheless produces a significant amount of waste material.
 Several devices have been developed in an effort to provide a
 "no-fold-back" transfer of a moving web. The applicant's prior U.S. Pat.
 No. 5,368,253, entitled Continuous Rewind With No-Fold-Back Splicer,
 discloses one such device. The device disclosed in the '253 patent uses a
 perforated knife to cut the web at a point which is upstream from the new
 core. Gaps in the perforated knife leave a set of tabs which hold the web
 together until the cut seam reaches the new core. At that point, the "new"
 leading edge of the web becomes bonded to a strip of adhesive on the new
 core. The adhesive bond overpowers the tabs thereby causing the tabs to
 break. As a result, the tail of the web continues on its normal path to
 become rewound about the old finish roll, while the new leading edge
 becomes bonded to the new core. The splice is made without the usual
 fold-back encountered in conventional splicing operation.
 The applicant's prior U.S. Pat. No. 5,823,461 entitled No-Fold-Back Splicer
 with Electrostatic Web Transfer Device discloses another example of a
 splicing device for a rewinder which produces a no-fold-back splice. On
 the device disclosed in the '461 patent the web is fed through a first nip
 point formed by an introducer roll and a cushioned anvil roll, and then
 through a second nip point formed by the cushioned anvil roll and the new
 core. An electrostatic charging bar positioned downstream from the first
 nip point emits an electrostatic charge onto the web to temporarily adhere
 it to the cushioned anvil roll. A rotatable cutting knife which is
 cooperatively engageable with the cushioned anvil roll cuts the web at a
 point downstream from the electrostatic charging bar but upstream from the
 new core thereby forming a tail and a new leading edge. The tail continues
 to be rewound about a finish roll. Because the new leading edge of the web
 has been electrostatically charged it remains stuck to the cushioned anvil
 roll until it reaches the new core. At that point, adhesive on the new
 core peels the new leading edge of the web off of the cushioned anvil roll
 and affixes it onto the new core. The web is thereafter rewound about the
 new core.
 However, the two devices disclosed in the '253 and '461 patents are both
 designed for use on or in connection with a turret style rewinder. As
 mentioned, a turret style rewinder includes a first core mounted on one
 end of the turret arm, and a second core mounted on the opposite end of
 the turret arm. The rewinding operation is normally conducted on the core
 that is located in the position closest to the end of the web processing
 line. In preparation for the splice, the turret arm is rotated so that the
 first core, which is ready to be finished and removed from the rewind
 stand, is rotated away from the web processing line and the new core is
 simultaneously rotated into position to take over the rewinding operation.
 (See, e.g., U.S. Pat. No. 5,368,253, FIGS. 1 and 2 and specification
 column 4, lines 30-50, and U.S. Pat. No. 5,823,461, FIG. 1 and
 specification column 3, line 66 to column 4, line 18.) During the period
 that the finish roll is positioned away from the web processing line, yet
 prior to splicing, the web must traverse a substantial distance while
 unsupported by any rollers or other structural components of the web
 processing equipment. Some web materials, such as very light weight films
 and foils, may become stretched, wrinkled, warped or might even tear while
 traveling over the unsupported area. Of course, such defects and
 imperfections are undesirable and oftentimes entirely unacceptable,
 resulting in the production of undue amounts of waste material. In order
 to avoid creating such defects and imperfections, delicate materials such
 as extremely thin films and foils are often applied to a rewind core with
 a lay-on roll. A lay-on roll is quite simply a roll that is located in
 close proximity to the rewind core. The lay-on roll and rewind core are
 close enough together to form either a nip point, or at most a short gap
 between the lay-on roll and rewind core. The lay-on roll therefore
 essentially applies the web directly onto the rewind core. As mentioned,
 conventional turret rewinders produce too large of a space for the web to
 cross over during the splicing step to be used in such applications.
 Other examples of no-fold-back splicers include the device disclosed in
 U.S. Pat. No. 4,422,528 to Richard S. Tetro (The Black Clawson Company)
 and another device produced by IMD Corporation, which uses a vacuum to
 transfer the web to the new core during the splicing operation. However,
 both devices are extremely complex and are severely limited to handling a
 narrow range of materials and web speeds.
 SUMMARY OF THE INVENTION
 A duplex web roll winding and splicing device for continuously winding a
 moving web and for cutting and transferring the web onto a new core with a
 no-fold-back and wrinkle-free splice is disclosed.
 The primary components of the invention include a nip roll, a lay-on roll,
 an electrostatic generating device, a cutting knife, a first core for
 winding a first roll of web material, and a second core for winding a
 second roll of web material. The nip roll is positioned immediately
 adjacent to the lay-on roll to form a nip point for the web to pass
 through. The electrostatic generating device is positioned in close
 proximity to the lay-on roll at a point which is downstream from the nip
 roll but upstream from the cutting knife. The cutting knife is positioned
 in close proximity to the lay-on roll at a point which is downstream from
 the electrostatic generator but upstream from both the first and second
 cores. Finally, the first and second cores are both positioned downstream
 from the cutting knife, and each core is independently moveable toward and
 away from the lay-on roll. Thus, either one or both of the cores may be
 positioned in close proximity to the lay-on roll at any particular time.
 The electrostatic generator is a device which emits an ion charge onto the
 web in order to temporarily bond or adhere the material to the surface of
 the lay-on roll. When the cutting knife cuts the web, the tail of the web
 continues on its normal path to become wound around the old finish roll.
 Because the new leading edge of the web is electrostatically bonded to the
 lay-on roll, it does not slip off, but remains there until it reaches the
 new core. At that point, adhesive on the new core peels the new leading
 edge off of the cushioned second roll and affixes it onto the new core.
 Thereafter the web is wound about the new core. As a result, the web is
 spliced and transferred to the new core without any fold-back or wrinkles.
 Additionally, because the two cores are independently moveable relative to
 the lay-on roll and relative to each other, both cores may be
 simultaneously positioned in close proximity to the lay-on roll.
 Consequently, no unduly wide gaps or spaces are created for the web to
 pass over. Instead the web is applied by the lay-on roll directly onto one
 core or the other even during the splicing operation. In other words, the
 lay-on roll is effectively always in contact with one of the rewind cores.
 When one roll is finished and the splice to the new core has been
 completed, the finish roll may at that point be independently moved away
 from the processing line to be removed and replaced with a new core, and
 then independently returned back into the rewind position and made ready
 for the next splice. The novel design of the duplex web winding and
 splicing apparatus is useful for winding a wide range of web materials,
 especially exceptionally light weight plastic films.
 The novel invention disclosed herein provides a number of additional
 advantages as well. The design is easily adaptable to accommodate a range
 of core diameters and core widths. The symmetry of the device makes it
 adaptable for either "over" or "under" winding. The lay-on roll can be
 more effectively driven so that build-up of the roll is controlled better.
 Because no turreting is required the size of the machine is comparatively
 compact, and in particular requires a substantially lower overall height
 compared to turret rewinders, thereby reducing space requirements in the
 plant.
 The primary objects of the invention are therefore to provide an apparatus
 and method for changing rolls on a continuous rewind operation which
 produces a no-fold-back and wrinkle-free splice especially adapted for
 delicate web materials that normally require a lay-on roll for winding the
 web about a core; to cut the web at a point before it reaches the new core
 and to control the web as it is introduced onto the new core; to provide a
 means for electrostatically charging the web in order to control its
 movement during the splice; to provide a means for applying an adhesive
 bond between the new leading edge of the web and the new core; to provide
 a means for transferring the new leading edge of the web to the new core
 such that the tail of the web is wound about the finished roll and the new
 leading edge is smoothly and flatly applied to the new core; to provide a
 means for independently moving a pair of cores toward and away from the
 lay-on roll so that the splice can be performed while both the finish roll
 and new core are in close proximity to the lay-on roll; and to provide a
 no-fold-back, wrinkle-free splicing mechanism which is adaptable for use
 in splicing a wide range of web materials on either high-speed or
 low-speed rewind operations.
 Other objects and advantages of the invention will become apparent from the
 following description which sets forth, by way of illustration and
 example, certain preferred embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 The duplex web roll winding and splicing apparatus disclosed herein is used
 primarily for the winding of paper, plastic films, foils, laminations and
 other web materials which have been processed on coating, printing,
 laminating, converting or other types of web processing equipment. A web
 11 is an extremely thin sheet-like material having a substantially uniform
 width and potentially unlimited length. The web is wound lengthwise into
 large rolls, sometimes referred to herein as finish rolls. Such rolls are
 also referred to in the industry as parent rolls or mill rolls. The
 apparatus and method disclosed herein are especially adapted for use in
 continuously winding a moving web and also for splicing the web onto a
 successive series of rolls in such a manner so as to avoid any fold-backs
 or wrinkling of the webs during the splicing operation.
 Referring in particular to the first embodiment illustrated in FIGS. 1-8,
 the apparatus 12 includes a frame 13 supporting a centrally located lay-on
 roll 14. The lay-on roll 14 is used to apply the web 11 onto a first core
 15 and second core 16, alternately. The lay-on roll 14 is preferably a
 substantially hollow roll having a relatively light mass. Additionally,
 the lay-on roll 14 is preferably mounted on a swing arm 17, which is in
 turn mounted on the frame 13, thereby enabling the lay-on roll 14 to move
 laterally a short distance between the first and second cores. The lateral
 movement of the lay-on roll 14 may be optionally controlled by a hydraulic
 or pneumatic cylinder 18 operatively connected to the swing arm 17 and to
 the frame 13.
 The web 11 is introduced onto the lay-on roll 14 by passing the web 11
 across a first idle roll 19 and a second idle roll 20. The second idle
 roll 20 may be alternatively referred to as a nip roll in that it is
 positioned in close proximity to the lay-on roll 14 so as to form a nip
 point between the nip roll 20 and lay-on roll 14. Referring to FIGS. 1 and
 3 in particular, the nip roll 20 is also preferably mounted on a second
 swing arm 21 for moving the nip roll 20 toward the lay-on roll 14 to form
 the nip point in preparation for splicing (discussed further below), and
 for optionally moving the nip roll 20 away from the lay-on roll 14 to form
 a short gap between the nip roll and lay-on roll during normal rewinding
 operations. A pneumatic or hydraulic cylinder 22 operatively connected to
 the nip roll swing arm 21 and to the frame 13 may be used to pivot the nip
 roll 20 toward and away from the lay-on roll 14. The web 11 is introduced
 onto the lay-on roll 14 by passing it through the nip point between the
 nip roll 20 and the lay-on roll 14.
 Immediately downstream from the nip point, an electrostatic charging bar
 23, connected to an electrostatic generator, is positioned across the
 width of the web 11 in close proximity to the lay-on roll 14 so that the
 web passes between the electrostatic bar and the lay-on roll. The
 electrostatic charging bar 23 emits an intense field of ions toward a
 ground point, which in this case is the lay-on roll 14. The ion charge
 temporarily adheres the web 11 electrostatically to the surface of the
 lay-on roll 14. Suitable electrostatic generators and charging bars are
 available from, for example, Simco, Hatfield, Pa., and from Hurletron
 Incorporated, Lincolnshire, Ill., as well as several other manufacturers.
 The apparatus further includes a first spindle 24 for supporting the first
 core 15 for winding the web 11 into a first roll 25, and a second spindle
 26 for supporting the second core 16 for winding the web 11 into a second
 roll 27. The first spindle 24 includes a means for selectively and
 independently moving the first core 15 toward and away from a first
 portion 28 of the lay-on roll 14. Referring to the preferred embodiment of
 the invention illustrated in FIGS. 1-8, the means for moving the first
 core 15 comprises a first pivot arm 29. The first pivot arm 29 includes a
 first end 30 attached to the frame 13 for rotation about a first pivot
 axis 31, and a second end 32 upon which the first spindle 24 is mounted. A
 first pneumatic or hydraulic cylinder 33 is operatively attached to the
 first pivot arm 20 and to the frame 13 for moving the first pivot arm 20,
 and thereby moving the first core 15 toward and away from the first
 portion 28 of the lay-on roll 14.
 The second spindle 26 includes means for selectively and independently
 moving the second core 16 toward and away from a second portion 34 of the
 lay-on roll 14. Referring again to FIGS. 1-8, the means for moving the
 second core 16 comprises a second pivot arm 35. The second pivot arm 35
 includes a third end 36 attached to the frame 13 for rotation about a
 second pivot axis 37, and a fourth end 38 upon which the second spindle 26
 is mounted. A second pneumatic or hydraulic cylinder 39 is operatively
 attached to the second pivot arm 35 and to the frame 13 for pivotally
 moving the second core 16 towards and away from the second portion 34 of
 the lay-on roll 14.
 With reference to FIG. 1, the first portion 28 of the lay-on roll is on one
 side of the lay-on roll 14, and the second portion 34 is on the opposite
 side of the lay-on roll 14. Consequently, the first pivot arm 29 and
 second pivot arm 35 are symmetrically mounted to the opposite sides of the
 frame 13. Additionally, the first and second pivot arms are capable of
 moving the first and second cores, respectively, toward and away from the
 lay-on roll independently of each other. Both the first portion 28 and
 second portion 34 of the lay-on roll 14 are downstream from the nip roll
 20, and the electrostatic charging bar 23.
 The apparatus 12 further includes a cutting knife 40 which extends across
 the width of the web 11 at a location which is downstream from the
 electrostatic charging bar 23 but upstream from both the first core 15 and
 second core 16. The knife 40 is preferably mounted on a rotatable knife
 holder positioned across the width of the web 11. The web 11 of course
 passes between the cutting knife 40 and the lay-on roll 14. The lay-on
 roll 14 acts like an anvil or cutting block in cooperation with the knife
 40 in order to cut the web 11. The outer surface of the lay-on roll 14 is
 preferably covered with a cushion of rubber or similar material. The knife
 40 is actuated so that the extreme edge of the knife rotates at
 approximately the same arch speed as the outer surface of the lay-on roll
 14, which is also the same linear speed that the web 11 is moving. Upon
 initiation of the cutting action of the knife 40, the knife 40 may be
 allowed to at that point rotate freely so that the knife 40 initially digs
 into the web 11 and into the outer cushion of the lay-on roll 14 and then
 is carried through the cutting arch at the same speed that the web 11 and
 lay-on roll 14 are moving. This cutting action provides for a straight,
 clean cut of the web material thereby producing a tail 41 and a new
 leading edge 42.
 Referring to FIG. 4, the cores 15 and 16 consist of long cardboard or metal
 tubes of the type commonly used to rewind web material. The core has an
 adhesive coating applied to its outer surface for bonding to the web to
 the core. Preferably, the core is provided with a narrow strip of
 double-sided adhesive tape 43 applied down the length of the core, and the
 splicing of the web 11 is synchronized with the rotation of the core so
 that the new leading edge 42 of the web is applied directly to the narrow
 strip of adhesive tape 43.
 The apparatus also preferably includes a first motor 44 operatively
 connected to the first spindle 24 for driving rotation of the first core
 15 in order to wind the web material to a first roll 25, and a second
 motor 45 operatively connected to the second spindle 26 for driving
 rotation of the second core 16 in order to wind the web material into a
 second roll 27. Preferably, the apparatus further includes a third motor
 46 for driving rotation of the lay-on roll 14 in order to have better
 control of the build-up of the web.
 As mentioned, the lay-on roll 14 is preferably mounted on a swing arm 17 to
 provide a small amount of lateral movement back and forth between the
 first core 15 and second core 16. The apparatus 12 preferably also
 includes a means for momentarily bumping the lay-on roll 14 against the
 core upon which the new leading edge 42 of the web is to be applied.
 Referring to FIGS. 1 and 3, the lay-on roll 14 may be bumped into the new
 core through the use of a hammer arm 47 operatively connected to a quick
 acting pneumatic cylinder 48. Upon actuation of the cylinder 48, the
 hammer arm 47 strikes the swing arm 17 thereby causing the lay-on roll 14
 to move a short distance towards the new core. Consequently, the new core
 may be placed a short distance away from the lay-on roll 14 in order to
 allow the tail 41 of the web to continue traveling to the roll upon which
 the web is being wound, and upon splicing the lay-on roll 14 is quickly
 moved into engagement with the new core so that the new leading edge 42 is
 applied onto the strip of adhesive tape 43 on the new core.
 Having thus described the preferred embodiment of the apparatus 12, the
 method for winding and splicing the web is as follows. Referring in
 particular to FIGS. 3, 7 and 8, the web 11 is introduced onto the surface
 of the lay-on roll 14 by feeding it through the nip point between the nip
 roll 20 and the lay-on roll 14. A first core 15 is placed onto the first
 spindle 24, and the first core 15 is then moved into close proximity to
 the first portion 28 of the lay-on roll 14. The web 11 is applied to the
 first roll 15 and wound about the first core into a first roll 25. A
 second core 16 is placed onto the second spindle 26, and the second core
 16 is then moved, independently of the first core 15, into close proximity
 to the second portion 34 of the lay-on roll 14.
 Upon passing through the nip point and being applied to the lay-on roll 14,
 the web 11 is then electrostatically charged at a location downstream from
 the nip point but upstream from the cores in order to temporarily adhere
 the web 11 onto the lay-on roll 14. The moving web 11 is then cut across
 its width at a location downstream from where the web is electrostatically
 charged but upstream from the cores. The web is severed completely in
 order to produce a tail 41 and a new leading edge 42. The tail 41
 continues to be wound about the first core 14. As the new leading edge 42
 approaches the second core 16, the second core 16 is placed in contact
 with the web so that the new leading edge 42 becomes affixed to the
 adhesive strip 43 on the second core 16. The adhesive strip 43 on the
 second core 16 essentially peels the new leading edge 42 away from the
 lay-on roll 14 and thereafter winds the web around the second core 16 into
 a second roll 27. Upon completion of the splice, the first core 15 is then
 independently moved away from the lay-on roll 14 so that the finished
 first roll 25 may be removed.
 The winding operation is continued and made ready for a further splice by
 replacing a new first core 15 onto the first spindle 24, and then
 independently moving the new first core 15 back into close proximity to
 the lay-on roll 14. The web is cut again to produce a second tail 49 and a
 second new leading edge 50. The second tail 49 is wound about the second
 core 16, and the second new leading edge 50 is then affixed onto the new
 first core 15 for winding the web into another roll. At that point, the
 second core 16 may then be independently moved away from the lay-on roll
 14 for removal of the finished second roll 27, with another new core
 replaced onto the second spindle 26. The above-described process may be
 repeated in order to continuously wind the web into a successive series of
 finished rolls.
 As mentioned, the sequence of events are preferably synchronized so that
 the new leading edge is applied directly onto the narrow strip of adhesive
 tape on the new core. This can be accomplished by placing a position
 sensor on the spindle for locating the relative position of the adhesive
 tape on the new core, by calculating the speed and distance that the web
 travels from the point that the web is cut to the point that it reaches
 the new core, and by controlling the timing of the cut made by the knife
 so that the new leading edge reaches the new core at the same moment that
 the adhesive tape comes in contact with the web.
 Finally, it is recognized that the present invention may be constructed in
 a number of configurations all of which satisfy the primary objective of
 continuously winding a moving web and for also providing a no-fold-back,
 wrinkle free splice of the web. For example, FIG. 9 depicts a second
 preferred embodiment of an apparatus 60 which likewise includes as
 essential elements a nip roll 61, electrostatic charging bar 62, cutting
 knife 63, lay-on roll 64, and first core 65 and second core 66. On the
 device depicted in FIG. 9, the means for independently moving the first
 core 65 comprises a first carriage 67. The first carriage 67 is slidable
 relative to the lay-on roll 64 for sliding the first core 65 toward and
 away from a first portion of the lay-on roll 64. The means for
 independently moving the second core 66 comprises a second carriage 68,
 the second carriage 68 being similarly slidable relative to the lay-on
 roll 64 for sliding the second core 66 toward and away from the second
 portion of the lay-on roll 64. Additionally, the lay-on roll 64 may be
 mounted on a slidable central carriage 69 to provide a slight amount of
 lateral movement between the cores.
 FIG. 10 depicts a further alternative embodiment of an apparatus 80 which
 likewise includes as essential elements a nip roll 81, electrostatic
 charging bar 82, cutting knife 83, lay-on roll 84, first core 85, and
 second core 86. Like the embodiment depicted in FIGS. 1-8, the embodiment
 depicted also includes pivot arms 87 and 88 for the first and second cores
 and a swing arm 89 for the lay-on roll. Furthermore, alternative
 mechanisms for actuating and repositioning the cutting knife may be
 employed, and in that regard the applicant's prior U.S. Pat. Nos.
 5,368,253 and 5,823,461 are incorporated herein by reference.
 Therefore, specific details of the apparatus and method disclosed above are
 not to be interpreted as limiting the scope of the invention, but are
 presented herein merely to provide a basis for the claims and for teaching
 those skilled in the art to make and use the present invention in any
 appropriately detailed manner. As mentioned, changes may be made in
 certain details of the preferred embodiments described above without
 departing from the spirit of the invention, especially as defined in the
 following claims.