Abstract:
A rewinder for rewinding a web into one or more rolls on separate cores, includes at least one rewinding mandrel having a distal end. The rewinder also has a supply device for supplying the web to the rewinding mandrel, and a drive device. The drive device can (a) rotate the rewinding mandrel in order to wind at least a portion of the web onto the rewinding mandrel, and (b) axially retract the mandrel to unload the portion of the web wound on the mandrel. Also included is a holder for holding the one or more rolls. The rewinder also has a lifter for (a) raising the holder to support the portion of the web wound on the mandrel, and (b) lowering the holder. This rewinding mandrel is rotated in order to wind at least a portion of the web onto the rewinding mandrel. The holder is then raised to support the portion of the web wound on the mandrel. Next, the mandrel is axially retracted to unload the portion of the web wound on the mandrel, before lowering the holder.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to material handling, and in particular, to equipment and methods for facilitating removal of finished rolls after rewinding. 
     2. Description of Related Art 
     Sheet material made of paper, plastic or other materials is manufactured in a web that is wound into a relatively large roll. In many instances, this roll is too large for use in other manufacturing processes. For that reason, the web is often unwound and rewound into smaller rolls. In some cases, the web is slit into a plurality of webs that are then simultaneously wound into a number of axially shorter rolls. 
     A difficulty with such rewinding is the labor involved with removing finished, rewound rolls. These rolls may be relatively heavy and require special handling equipment. Also, the finished rolls may be distributed on a number of separate mandrels and special techniques are needed to remove these rolls in an orderly fashion. 
     In U.S. Pat. No. 4,611,769 a slitter feeds strips to one of the shafts on a turnstile. After a group of rolls is wound, the turnstile moves the shaft to an unloading position where the shaft is retracted to allow the rolls to fall onto an unloading plate. The retracted shaft is later moved with the turnstile to a loading position and redeployed to penetrate the centers of a fresh batch of empty cores. This arrangement is only satisfactory for relatively lightweight rolls that can be swung by a turnstile and later allowed to fall as a winding shaft retracts. 
     U.S. Pat. No. 3,845,915 shows a cantilevered shaft that is axially movable for either positioning or ejecting a roll. An ejected roll can fall “onto a hoisting device which then transports the roll out of the machine.” Column 3, lines 33-34. This reference has little disclosure on the unloading of the rolls. 
     In U.S. Pat. No. 5,217,177 strips are wound on spindles that are mounted on a revolver. A loaded spindle can be taken off the revolver by a turret to a station where a comb can pull the rolls off the spindle while new cores are loaded from the opposite end. The spindle does not axially retract. 
     In U.S. Pat. No. 5,620,151 a slitter feeds a rewinder. When a complete roll is wound, a lifter rises to support the roll. After contact with the roll is detected, chucks disengage the roll, which is then lowered to a carriage that carries the roll from the machine. This reference does not disclose techniques for axially shifting the rolls. 
     In U.S. Pat. No. 4,346,852 a table moves between a core loading station and a station for winding and discharging rolls. When a roll is wound, holding devices are released and the rolls are lowered by receivers. Again, this reference does not disclose techniques for axially shifting the rolls. 
     For devices that lower a roll on swing arms, see U.S. Pat. Nos. 4,508,283; 4,749,140; 5,356,087; and 5,445,341. For a device that lowers a roll on hoisting hooks, see U.S. Pat. No. 5,121,885. 
     See also U.S. Pat. Nos. 4,458,853; and 5,782,425. 
     SUMMARY OF THE INVENTION 
     In accordance with the illustrative embodiments demonstrating features and advantages of the present invention, there is provided a rewinder for rewinding a web into one or more rolls on separate cores. The rewinder includes at least one rewinding mandrel having a distal end. The rewinder also has a supply means for supplying the web to the rewinding mandrel, as well as a drive means. The drive means can (a) rotate the rewinding mandrel in order to wind at least a portion of the web onto the rewinding mandrel, and (b) axially retract the mandrel to unload the portion of the web wound on the mandrel. Also included is a holder for holding the one or more rolls. The rewinder also has a lift means for (a) raising the holder to support the portion of the web wound on the mandrel, and (b) lowering the holder. 
     According to another aspect of the invention, a method is provided employing a holder and at least one rewinding mandrel for rewinding a web into one or more rolls on separate cores. The method includes the step of rotating the rewinding mandrel in order to wind at least a portion of the web onto the rewinding mandrel. Another step in the method is raising the holder to support the portion of the web wound on the mandrel. The method also includes the step of axially retracting the mandrel to unload the portion of the web wound on the mandrel, and lowering the holder. 
     By employing apparatus and techniques of the foregoing type, an improved unloading technique is achieved. In a preferred embodiment, a web is pulled from a large roll, in some cases being divided into several strips by a web slitter. This preferred embodiment has a pair of mandrels, although a different number of mandrels may be employed instead. These mandrels may grip the cores on which the web is rewound firmly without slipping, or loosely with slipping permitted. The cores can be gripped preferably with a tab that is deployed by an inflatable bladder inside the mandrel. When slipping is permitted, the cores may be kept in a desired axial position by a number of locating tabs that are deployed by another inflatable bladder inside the mandrel. The web, if slit, may be wound into a plurality of separate rolls on the mandrels. Each roll will preferably be rewound with the incoming web passing over a touch roll that touches the growing roll in order to avoid air entrapment and to stabilize the rewinding process. A retractable center support can be articulated into a central position on the mandrel to prevent sagging for embodiments with relatively long mandrels. 
     When a roll has been rewound on a mandrel, the preferred control system will automatically stop rotation of the mandrels and allow the operator to cut the web. The resulting loose tail of the incoming web can be caught on a preferred tail support bar that rises into position to catch this loose tail and prevent it from becoming entangled with the rolls or roll holder during an unloading sequence. 
     The mandrels may be rotatably mounted on a journal that rides on axially extending tracks. The journal can be moved axially by a driving belt that connects to the journal. In one embodiment, the mandrel is rotated in the journal by a series of pulleys that are driven by an engagement wheel with a number of apertures. Spring-loaded pins on a motor-driven drive wheel can engage these apertures when the journal moves into a working position. 
     In a preferred embodiment, an urging means can axially shift finished rolls that are rewound onto cores on the mandrels. For the lower mandrel a pressure plate is mounted on a pressing bar that axially extends to shift the finished rolls to the distal end of the mandrel. For the upper mandrel a similar pressure plate and pressing bar can be deployed but by a lesser amount. In this latter case, the mandrel can be retracted to retract the finished rolls and stack them against the upper pressure plate. An excessively high bending moment could be applied to the upper mandrel if it were retracted unsupported, with a full load of finished rolls. For this reason, a hook-like grappling means is connected to the distal end of the upper mandrel to follow and support this distal end during retraction. 
     A preferred holder, in the form of a platform, is supported by end rollers that act as followers that ride between vertical guides. This platform is designed to rise and support finished rolls that are rewound onto cores on the mandrels. Preferably, load sensors on the platform can detect when the platform has reached and is supporting the finished rolls. 
     As an example, the platform can rise to support rolls on the lower mandrel, which can then fully retract as its journal is pulled back by the above mentioned drive belt. If the above mentioned pressure plate was just operated, all of these finished rolls will be positioned for delivery to one end of the platform. Under these circumstances, the platform can then rise to the upper mandrel. Assuming the upper mandrel has retracted to bring the finished rolls against the deployed pressure plate, these finished rolls will be delivered to the opposite end of the platform as the upper mandrel fully retracts. 
     Once loaded, the platform can descend along the guides. The lower end of one of the vertical guides preferably diverges at a lower spur to allow a follower to retreat, so that the platform tilts. This tilting causes the finished rolls to roll off the platform. While the foregoing describes unloading both mandrels in one session, in other modes, the mandrels can be separately unloaded in two separate sessions. In still other modes a single roll can be rewound on a single mandrel (log wind). 
     In another embodiment, the holder platform could be detachable from the lifting mechanism and have casters that would permit transportation either manually or under power to another location for unloading. 
     In the preferred embodiment, the system can then go into a configuration that facilitates the loading of fresh cores. For example, with the platform in the down position, the mandrels can extend 90% to provide some clearance for loading fresh cores. In the preferred embodiment, the bearings that normally support the distal ends of the mandrels can also retract vertically to provide additional clearance for loading fresh cores. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above brief description as well as other objects, features and advantages of the present invention will be more fully appreciated by reference to the following detailed description of presently preferred but nonetheless illustrative embodiments in accordance with the present invention when taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a schematic diagram of the web path from an unwinding roll to rewinding rolls in a rewinder according to principles of the present invention; 
     FIG. 2 is an axonometric view of the rewinder of FIG. 1; 
     FIG. 3 is a detailed axonometric view of a portion of the rewinder of FIG. 2 near the distal end of the mandrels; 
     FIG. 4 is a detailed schematic diagram of a portion of the web path of FIG. 1 near the mandrels; 
     FIG. 5 is a detailed axonometric view of the upper, retractable end support of FIG.  2  and its relationship to its mandrel and the grappling means; 
     FIG. 6 is an axonometric viewing of a portion of one of the retractable center supports of FIG. 3 about to engage its mandrel; 
     FIG. 7 is an exploded, axonometric view of the mechanism supporting the carriage that carries the touch roll of FIG. 3; 
     FIG. 8 is a cross-sectional view of the touch roll and supporting beam of FIGS. 3 and 7; 
     FIG. 9 is an axonometric view of axially extending tracks carrying a journal for one of the mandrels of FIG. 2, which is driven by a drive means; 
     FIG. 10 is a side view, partially in section, of a portion of the drive means of FIG. 9; 
     FIG. 11 is an end view of the rewinder of FIG. 2 with its side frame shown in phantom; 
     FIG. 12 is a schematic diagram of a control means connecting to various pieces of equipment associated with the rewinder of FIG. 2; 
     FIG. 13 is a front view of the manually operable input device of FIG. 12, showing a touch screen and a number of other manual controls; 
     FIGS. 14A through 14F show a sequence of operations being performed by the rewinder of FIG. 2 in an automatic shared mode; 
     FIGS. 15A and 15B show a sequence of operations being performed by the rewinder of FIG. 2 in an automatic discrete mode; and 
     FIGS. 16A through 16D are flow charts illustrating operations associated with the control means of FIG.  14 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, a rewinder is shown rewinding rolls  10  and  12  on the cores  16 , which are mounted on a first (lower) rewinding mandrel  18  and a second (upper) rewinding mandrel  20 . The rolls  10  and  12  are fed by a supply roll  22 , which is wound with a web  24 . Supply roll  22  is mounted on a mandrel  26  (or by chucks located at both ends) that can be motor driven and/or braked so that web  24  is supplied at a predetermined tension. This tension can be controlled by a conventional feedback loop (not shown). 
     Web  24  is supplied over an idler roller  28  and a load cell idler  30  to a another driven roller  32  that is part of a supply means. Driven roller  32  cooperates with a nip roller  34  to deliver web  24  over idler rollers  36 ,  38  and  40 . The web  24  need not follow the illustrated path but may be routed to different sides of the idler rollers, as suggested by the alternate course of broken line  24 A. 
     In this embodiment, web  24  is shown routed through a slitter comprising a driven anvil (female knife)  42  cooperating with blade wheel  44  to deliver a number of slitted webs around idler roller  45 . In a known manner, web  24  can be slit into a plurality of narrower webs, some routed along course  46  and others routed along course  48 . Webs routed through course  46  pass around driven roller  50 , which cooperates with nip bar  52 . After passing around driven roller  50 , the webs on course  46  pass over touch roll  54  before being wound into rolls  12 . Webs routed along course  48  pass around driven roller  56 , which cooperates with nip bar  58 . After passing around driven roller  56 , the webs on course  48  pass over touch roll  60  before being wound into rolls  10 . Bars  52  and  58  are round bars that do not rotate. They nip against rollers  50  and  56  to clamp web tails during the subsequently described unload sequence. This helps maintain tension on webs leading back to the knives. 
     Referring to FIGS. 1-4, the previously mentioned rolls  10  are shown as five separate rolls  10 A through  10 E mounted on mandrel  18 . Previously mentioned rolls  12  are shown as four separate rolls  12 A through  12 D mounted on mandrel  20 . Mandrels  18  and  20  are shown with gripping means in the form of gripping tabs  84  and  86 , respectively. Gripping tabs  84  and  86  are axially repositionable in a longitudinal track in the mandrels over an internal strip (not shown) that can be outwardly driven by an inflatable bladder (not shown) inside the mandrels. Axially repositionable locating tabs  88  and  90  are shown mounted on mandrels  18  and  20 , respectively, at angular positions that are different than that of tabs  84  and  86 . Locating tabs  88  and  90  are axially repositionable in a longitudinal track in the mandrels over an internal strip (not shown) that can be outwardly driven by an inflatable bladder (not shown) inside the mandrels. The inflatable bladders that drive tabs  84  and  88  are located at angularly spaced positions inside mandrel  18 . Likewise, the inflatable bladders that drive tabs  86  and  90  are located at angularly spaced positions inside mandrel  20 . 
     A retractable center support is shown as an arm  62  mounted on shaft  64 . Arm  62  has a hooked distal end  66  for centrally supporting the underside of second mandrel  20 . Arm  62  can be rotated through a pneumatically actuated lever arm  65 , schematically illustrated in FIG. 4. A rotatably mounted retractable center support  68  is shown with a hooked end  70  centrally supporting first mandrel  18  (FIG.  3 ). Support  68  is rotatably supported on a shaft, illustrated schematically in FIG. 4 as shaft  72 . Shaft  72  is rotated by lever arm  73 , which is schematically shown linked to the drive arm  67  on shaft  64 . Thus linked, rotation of pneumatically operated arm  65  simultaneously rotates linked arms  67  and  73  to likewise rotate support arms  62  and  68 . In the preferred embodiment, once the center supports are in place a hydraulic ram (not shown) is advanced to mechanically latch the center supports in place. 
     The distal end  21  of mandrel  20  is shown in FIG. 3 supported by a swinging hook  74 , referred to herein as a grappling means. As described further hereinafter, swinging hook  74  can support and follow the distal end  21  of mandrel  20  as it retracts with a load of rolls, such as rolls  12 A- 12 D. The distal end  19  of mandrel  18  does not have such a grappling means in this embodiment, although both mandrels could be supplied with grappling means in alternate embodiments. Swinging hook  74  is shown mounted on a carrier  76  (FIG.  2 ). In this embodiment, hook  74  has on its upper end a linear bearing (not shown) that rides on a track on carrier  76 . Carrier  76  is rotatably mounted between side frame  78  and frame assembly  80 . Carrier  76  can be rotated pneumatically using the lever arm  82  illustrated schematically in FIG.  4 . 
     Frame assembly  80  supports among other things, mandrels  18  and  20  and is adjacent to a cabinet  265  housing equipment for rotating and retracting/extending the mandrels, etc. 
     A pair of horizontal bars  106  and  108 , herein referred to as tail supports, are mounted between two pairs of support brackets  110  and  112 , respectively. The brackets  110  and  112  are mounted on opposite ends of carrying rods  114 . Two identical carrying rods  114  are mounted near frame  78  and frame assembly  80 . Each of the carrying rods  114  can be lifted by an air cylinder (not shown) to lift the support rods  106  and  108 . 
     Referring to FIGS. 2,  3 ,  4 , and  11 , a holder, shown as platform  92 , is supported at either end by upright struts  94 . Struts  94  are located off-center and support a pair of followers  96  in the form of a pair of wheels that ride between the vertical guides  98 . The inner one of the guides  98  has a lower spur  100  that diverges outwardly to increase the spacing between the guides. Accordingly, platform  92  is kept relatively level when the followers  96  are riding between the upper portions of guides  98 . However, the lower one of the followers  96  will occasionally reach the lower spur  100  and swing backwardly to allow tilting of platform  92 . Platform  92  is lifted by a chain  102 , which is part of a lift means. Chain  102  rides over a pulley  104  and may terminate in a counter weight (not shown). Chain  102  can be driven by a pneumatic cylinder attached to the end of the chain. Alternatively, pulley  104  can be rotated by an electric motor (not shown). 
     In one embodiment the holder platform can employ a platform that is elevated by a scissor-like structure having a pair of pivotally connected members. In another embodiment, the holder platform could be detachable from the lifting mechanism and have casters (not shown) that would permit transportation either manually or under power to another location for unloading. 
     Referring to FIGS. 2 and 5, previously mentioned side frame  78  is shown supporting a slide plate  116 . Previously mentioned grappling means  74  is shown in a working position adjacent to side plate  116 . Grappling means  74  can also retract by swinging backwardly as illustrated by the phantom position. In the working position, hooked lower end  75  can engage the distal end  21  of mandrel  20 . (For clarity, mandrel  20  is shown retracted from the hooked end  75  of grappling means  74 , although normally mandrel  20  will be deployed inside the hooked end  75  whenever it descends to the illustrated working position.) 
     A collar-like journal  118  (also referred to as a chuck) is shown centrally mounted on a lower portion of the plate  116  for rotatably supporting the reduced diameter portion  21  A of distal end  21  of mandrel  20 . As described in further detail hereinafter, mandrel  20  can alternately extend into, and retract from, journal  118 . Also, after retraction of the mandrel, plate  116  can be pneumatically lifted upwardly into the notch  120  in side frame  78 . Accordingly, plate  116  and journal  118  can act as a retractable end support. In FIG. 2 a similar slide plate  116 ′ is shown acting as a retractable end support for mandrel  18 . As before, a notch  120 ′ in side frame  78  allows clearance when slide plate retracts upwardly. 
     Referring to FIG. 6, previously mentioned support arm  62  is shown about to swing into position under mandrel  20 . It will be appreciated that the description of this figure will likewise apply to previously mentioned support arm  68  (FIG.  3 ). A pair of side plates  122  and  124  are attached to opposite sides of the distal end of support arm  62 . Rotatably mounted between plates  122  and  124  are a pair a rotatably supported wheels  126  and  128 . Wheels  126  and  128  project slightly above the upper edges of plates  122  and  124 . A circumferentially grooved collar  130  is releasably clamped to mandrel  20 , so that wheels  126  and  128  can ride in the groove of collar  130 . 
     Referring to FIGS. 7 and 8, a rack  132  is shown attached to the inside face of side frame  78 . It will be appreciated that the structure shown in this figure will be replicated on the opposing inside face of frame assembly  80  (FIG.  2 ). A pinion  134  is shown driven by a motor  136  by means of drive shaft  138 . Motor  136  is supported by shaft  138 , but is prevented from rotating by a follower wheel  140  attached to the motor and riding in slot  142 . Shaft  138  is journaled in bracket  144 , which is attached between hollow beam  146  and linear bearing  148 . The bearing  148  rides on track  150  mounted on the inside face of side frame  78 . The bracket  152  attached to the underside of beam  146  supports a photo-detector  154 , which controls retraction of the beam  146 , in response to growth of the previously mentioned rewinding roll, in a manner to be described hereinafter. 
     A linear bearing  156  attached to the forward face of beam  146  supports a laterally adjustable bracket  158 , which can be locked in place by turning handle  162  to tighten the threaded shaft  160 . A standard  164  attached to bracket  158  pivotally supports a pair of levers  166 , which rotatably support touch roll  54  (or in another location touch roll  60 ). The upper end of bracket  158  supports a pneumatic cylinder  168  that can be operated to swing the levers  166 . A pair of pressure channels  170  are mounted atop beam  146 . Channels  170  have a number of fittings  172  that can be used to provide pneumatic pressure to cylinder  168  at the various positions where it may be located along the beam  146 . 
     Referring to FIGS. 9 and 10, mandrel  18  is shown connected to a drive means including a journal  174 , which is a relatively long bearing supported on a platform  176 . Platform  176  includes a linear bearing (hereinafter shown) that rides on the axially extending tracks  178  mounted along the longitudinal opening in C-shaped beam  180 . A motor-driven belt  182  connects to platform  176  to move journal  174  along tracks  178 . A bearing block  184  mounted in one corner of platform  176  rotatably supports pulleys  186  and  188 . An engagement means is shown as a wheel  190  with four equiangularly spaced apertures  196 . Wheel  190  is mounted on a common shaft  191  with pulley  188  to drive that pulley. Pulley  188  drives a belt  192  that circulates over idler pulley  186  and a driven pulley  194 , which is coaxially connected to mandrel  18  in order to drive it. 
     An axially stationary drive pulley  198  (also referred to as a rotor) is mounted on a common shaft  200 , rotatably supported on bearing housing  202 , to be rotated by a motor-driven belt  204 . Pulley  198  has a pair of axial bores fitted with spring loaded pins  206  and  208  located at diametrically opposite positions. Pins  206  and  208  have inside flanges that keep the pins trapped inside the bores in pulley  198 . These bores contain springs  210  and  212 , which are trapped between backer plate  214  and pins  206  and  208 , respectively. Arranged in this fashion, wheel  190  can move against pins  206  and  208 , which can retract. As rotor  198  turns, eventually pins  206  and  208  reach the apertures  196  and snap into these apertures so that pulley  198  can drive the wheel  190 . 
     In other embodiments the motor for driving the mandrel can move axially with the mandrel, in which case the foregoing engagement means is unnecessary. 
     Referring to FIG. 12, a control means is shown herein as a programmable logic controller  216  (also referred to as a digital processor means). Controller  216  is a digital computer having a memory  218  and an input/output section  220 . Input/output section  220  has drive circuits connecting to blocks  222 - 243  in order to operate relays and other equipment needed to control the foregoing rewinder. Block  222  has an output for controlling the supply roll  22  (FIG.  1 ). The unwinding supply roll  22  can have a drive motor and/or brake to regulate the web delivery. This subsystem can also have a sensor (not shown) for measuring web tension to produce a feedback signal to control the above mentioned motor and/or brake. 
     Block  224  has two outputs for controlling the drive to the motors that rotate the upper and lower mandrels  18  and  20  (see FIG.  9 ). Block  226  has outputs for controlling inflation of the bladders inside mandrels  18  and  20 . Specifically, this block can control the gripping tabs  84  and  86 , as well as the locating tabs  88  and  90  (FIG.  3 ). Block  228  can control the extension and retraction of mandrels  18  and  20  by operating the motor-driven belt  182  (FIG.  9 ). Block  230  can control the articulation of hook  74  by operating the pneumatic cylinder that controls lever arm  82  (FIG.  4 ). Block  232  can articulate the arms  62  and  68  by operating the pneumatic cylinder that rotates lever  65  (FIG.  4 ). 
     Block  234  can operate platform  92  by circulating chain  102  (FIG.  4 ). Block  234  can also receive input signals that sense the weight of rolls being supported on the platform  92 . In the preferred embodiment, two pressure sensitive mats are placed at opposite ends of the platform to act as load sensors for detecting weight on either the left or right end of the platform, in order to produce a corresponding weight signal. 
     Block  236  controls pushers that will be described presently. Block  238  can control both of the retractable end supports, such as the one shown in FIG.  5 . Block  240  can control the touch rolls  54  and  60 . Specifically, block  240  can control the pressure applied to cylinder  168  (FIG. 8) and the position of beam  146  carrying the touch rolls by operating motor  136  (FIG.  7 ). As described further hereinafter, motor  136  can be controlled by the positioning signals received from photo-detector  154 . Block  242  can operate the motors of the supply means that supplies the web. Block  243  can operate the web tail puller  106  and  108  (FIG.  3 ). 
     FIGS. 12 and 13 show a manually operable input device  244  having a touch screen  246 . Screen  246  is an LCD display that can produce an image of a virtual pushbutton. Screen  246  is touch-sensitive so that the displayed buttons can actually be “pressed” in the sense that the computer  216  attached to device  244  can sense tactile pressure on the screen at a determinable position. Buttons  248 - 258  are conventional pushbuttons that are labeled to indicate the following functions: Run, Jog, Emergency Stop Reset, Machine Stop, Unload Sequence Stop, and Emergency Stop. The nature of these functions will be described further hereinafter. 
     Knob  260  is designed for adjusting the web speed. The angular position of knob  260  can be detected by the previously mentioned computer  216  and can be taken as an operator command to establish web speed at a desired magnitude. Knob  262  is designed for adjusting the unwind tension from the supply roll  22  (FIG.  1 ). The angular position of knob  262  can be detected by the previously mentioned computer and can be taken as an operator command to establish web tension at the supply roll  22 . Device  244  is shown in FIG. 2 as a case mounted on support rod  276 . 
     Referring to FIGS. 14A through 14F, previously mentioned mandrel  18  is shown rotatably mounted in journal  174 , which is supported on the platform  176  that rides on the linear bearings  177  on track  178  of beam  180 . In a similar fashion, mandrel  20  is shown rotatably mounted in journal  174 ′, which is supported on the platform  176 ′ that rides on the linear bearings  177 ′ on track  178 ′ of beam  180 ′. Mandrels  18  and  20  are shown with their distal ends  19  and  21  supported in chucks  118 ′ and  118  (also referred to as retractable end supports). 
     A first urging means is shown as pusher plate  268  mounted on one end of threaded rod  266 . Rod  266  is threadably supported in the motor-driven, threaded collar  264  to act as a lead screw. Accordingly, rotation of collar  264  will cause pusher plate  268  to extend and retract. A second urging means is shown with a pusher plate  274  mounted on one end of guide rod  272 . Rod  272  is axially movably mounted in collar  270 . Pneumatic actuation will cause pusher plate  274  to extend and retract. 
     To facilitate an understanding of the principles associated with the foregoing apparatus, its operation will be briefly described. Referring to the flow chart of FIG. 16A, an operator may set various parameters at step  276  using touch screen  246  (FIG.  13 ). In addition, the operator can save all of these parameters to memory  218  of control means  216  (FIG. 12) for later recall. 
     In this manner, the operator may enter the thickness and density of the web, as well as the desired tension in the web as it unwinds from the supply roll  22  (FIG.  1 ). The operator may also enter the number and the width of the rolls that are to be rewound on the mandrels  18  and  20 . The operator may also enter the diameter of the cores  16 , as well as the desired outside diameter of the finished rolls  10  and  12  on the mandrels  18  and  20 . As an alternate target for ending the rewinding process, the operator can also enter the desired length of web to be rewound. The operator may also enter a web length adjustment factor for initial calibration of the length measurement means. 
     Since the desired tension in the web preferably varies during the process, the operator can enter the desired web tension for the beginning and end of the rewinding process. The operator may also enter the desired pressure to be applied by the touch rolls  54  and  60  (FIGS.  3  and  4 ). In some embodiments, the touch rolls can be pressured by different size pneumatic cylinders. For this reason, the operator can enter the size of the installed pneumatic cylinders to allow accurate adjustment of the pressure of the touch rolls  54  and  60 . Also, in some cases the pressure applied by the touch rolls  54  and  60  ought to vary dynamically. For this reason, the operator may enter a compensation value that will increase the pressure of the touch rolls as speed increases. It has also been found that the pressure of the touch rolls may need to be increased as the rewinding package increases in diameter. Accordingly, the operator can enter a compensation value that provides the desired amount of increase. 
     In some cases it is desirable to allow the mandrels  18  and  20  to slip inside cores  16  by running the mandrels at a speed in excess of that needed to produce the desired web speed. The operator can specify this overspeed or slip speed by entering (1) a desired slip speed in rpm, or (2) a percentage overspeed value based on the speed needed to produce the desired web speed. 
     While the torque applied to the mandrels  18  and  20  might normally determine the tension of the web being rewound onto the mandrels, various mechanical losses may affect this value. For this reason, the operator may enter a friction compensation value that allows more precise control of tension. 
     The operator may also enter the time permitted for accelerating and decelerating mandrels  18  and  20 . Additionally, the operator can enter the speed at which the machine will advance when the operator depresses the jog control button  250 . 
     In step  278  (FIG. 16A) the operator can indicate through touch screen  246  how rolls will be removed from mandrels  18  and  20 . In this example, the operator will select manual unloading of both mandrels together, which is also referred to herein as the manual shared mode. In the manual mode, the operator is prompted to initiate each subsequent action in the unloading process. In addition, a fully automatic mode exists which steps through the entire cycle while only prompting operator actions that are manually performed within the overall sequence such as cut-off and core loading operations. Automatic removal will only be allowed if the diameter of the rewound rolls exceeds 12 inches (30.5 cm). In other cases, the two mandrels can be unloaded in separate stages, if desired. In still other cases, only one mandrel will be rewinding and will contain a single roll (log roll mode). 
     In step  280  the operator can press a virtual “start” button displayed on touch screen  246  to begin the unloading sequence, assuming the rolls have been fully rewound to the target dimension. In succeeding step  282 , computer  216  will send a signal through block  240  (FIG. 12) to the actuators for the touch rolls  54  and  60  (FIG.  4 ). Specifically, pneumatic cylinders  168  (FIG. 8) will be activated to withdraw the touch rolls, while electric motor  136  (FIG. 7) will be activated to withdraw the beam  146  carrying the touch rolls. The system will also verify execution of the desired action by monitoring changes in the signals in any feedback loop associated with the touch rolls. 
     Next in step  284 , computer  216  will send a signal through block  226  to retract the tabs  84 ,  86 ,  88 , and  90 . In the following step  286 , block  224  will cause mandrels  18  and  20  to rotate at 5 rpm to bring the gripping tabs  84  and  86  to a 6 o&#39;clock (down) position, as sensed by position sensors (not shown), in order to maximize the clearance between the cores  16  and the mandrels. Again, the system will also verify execution of the desired action by monitoring these position sensors. Once the mandrels  18  and  20  have been properly positioned, the drive to the mandrels is disabled in step  288 . 
     In step  290  (FIG. 16B) computer  216  will display on screen  246  the message “Operator to Cut Tails.” In response, the operator must now cut the web near the rolls on mandrels  18  and  20 , thereby producing relatively short tails from these rolls. Once these tails are cut, the operator can signal completion of this cutting operation by depressing a virtual, flashing pushbutton displayed on touch screen  246  and labeled “Operator Procedure Completed.” Thereafter in step  292 , the operator will be presented with a flashing, virtual pushbutton labeled “Center Supports Lower.” Upon pressing this virtual pushbutton, computer  216 , operating through block  232 , will operate the associated pneumatic cylinder to rotate lever  65  and retract arms  62  and  68  (FIG.  4 ). Thereafter in step  294  the operator will be presented with a flashing, virtual pushbutton labeled “Raise Rewind Web Tail Puller.” Upon pressing this virtual pushbutton (in the automatic mode the process proceeds without requesting or awaiting a manual signal from an operator), computer  216 , operating through block  243 , will operate the associated pneumatic cylinder to lift web tail puller bars  106  and  108  (FIG.  3 ). Bars  106  and  108  will hold the ends of the incoming web so they do not fall into the path of the rolls during unloading and become tangled. 
     Next in step  296  a flashing, virtual pushbutton labeled “Roll Pushers Extend” can be pressed. When this pushbutton is pressed (in the automatic mode the process proceeds without requesting or awaiting a manual signal from an operator), computer  216 , operating through block  236  will operate the lead screw mechanism  264  and pneumatic actuator  270 , which in other embodiments could be a lead screw mechanism. Pusher plate  268  will extend to move the rolls  10 A- 10 E from the position shown in FIG. 14A to the right position shown in FIG.  14 B. Pusher plate  268  will extend to a calculated position. The actual position of pusher plate  268  is continually measured and fed back to computer  216  by a position sensor (not shown) associated with pusher plate  268 . Note that pusher plate  274  will also be extended at this time, but without further effect. Computer  216  will now display a virtual, flashing pushbutton labeled “Upper Hooker Engage.” When this pushbutton is pressed (in the automatic mode the process proceeds without requesting or awaiting a manual signal from an operator), computer  216 , operating through block  230 , will rotate pneumatically operated lever  82  (FIG. 4) to swing hook  74  onto the distal end  21  of mandrel  20 . 
     Computer  216  will now display a virtual pushbutton on touch screen  246  labeled “Upper Mandrel Retract.” When this pushbutton is pressed (in the automatic mode the process proceeds without requesting or awaiting a manual signal from an operator), computer  216 , operating through block  228 , will retract journal  174 ′ as shown in FIG.  14 C. Journal  174 ′ will ride on linear bearings  177 ′ under the control of a driving belt, similar to driving belt  182  shown in FIG.  9 . The positions of the mandrels are monitored continuously by computer  216  by a position feedback device (not shown) on the mandrels. As mandrel  20  retracts, hook  74  stays connected to distal end  21 . Hook  74  is mounted through a linear bearing to shaft  76  (FIG.  2 ). Hook  74  is biased by an air cylinder (not shown) to move to the left (as viewed in FIG.  2 ). Accordingly, rolls  12 A- 12 D will be drawn to the left against pusher plate  274  into a position that avoids later interference with rolls  10 A- 10 E. 
     The system will verify the execution of a proper response by monitoring the signals associated with hook  74 , mandrel  20 , lead screw mechanism  264 , and pneumatic actuator  270 . 
     In step  298  a flashing, virtual pushbutton will be displayed on touch screen  246  labeled “Raise Cart to Lower Mandrel.” When this pushbutton is pressed (in the automatic mode the process proceeds without requesting or awaiting a manual signal from an operator), computer  216 , operating automatically through block  234 , will pull chain  102  and lift platform  92  (FIG.  4 ). Platform  92  will rise until reaching the position shown in FIG.  14 C. At this time, a pressure sensitive mat (load sensor) on platform  92  will relay a weight signal through block  234  to computer  216  as indicated by step  300 . In response, computer  216  will stop platform  92 , as indicated by step  302 . 
     If instead, the system is in the “fully manual” mode, then platform  92  will only move when the operator is pressing the virtual pushbutton. In this latter case, the operator will observe the motion of the platform  92  in order to pilot it into a position for supporting the rolls  10 A- 10 E. 
     In step  304  a flashing, virtual pushbutton will be displayed on screen  246  with the label “Lower Mandrel Retract.” If this pushbutton is pressed (in the automatic mode the process proceeds without requesting or awaiting a manual signal from an operator), computer  216 , operating through block  228 , will circulate belt  182  (FIG. 9) to retract journal  174  and mandrel  18  to the position shown in FIG.  14 C. Accordingly, rolls  10 A- 10 E will be totally supported on the right end of platform  92 . Also, by providing a virtual, flashing pushbutton labeled “Lower Mandrel Retract” the operator can signal a command through computer  216  and block  236  to operate lead screw mechanism  264  and retract pusher plate  268  to the position shown in FIG. 14D (in the automatic mode the process proceeds without requesting or awaiting a manual signal from an operator). 
     In step  306  (FIG. 16C) computer  216  displays on touch screen  246  a flashing, virtual pushbutton labeled “Raise Cart to Upper Mandrel.” If this pushbutton is pressed by the operator (in the automatic mode the process proceeds without requesting or awaiting a manual signal from an operator), computer  216 , operating through block  234 , will pull chain  102  (FIG. 4) to lift platform  92 . Platform  92  will rise with rolls  10 A- 10 E until reaching the position shown in FIG.  14 D. At this time, a pressure sensitive mat (load sensor) on the left of platform  92  will relay a weight signal through block  234  to computer  216  as indicated by step  308 . In response, computer  216  will stop platform  92  as indicated by step  310 . 
     If instead, the system is in the “fully manual” mode then platform  92  will only move when the operator is pressing the virtual pushbutton. In this latter case, the operator will observe the motion of the platform  92  in order to pilot it into a position for supporting the rolls  12 A- 12 D. 
     Next in step  312 , computer  216  retracts hook  74  from the distal end  21  of mandrel  20 . Also, computer  216  retracts journal  174 ′ and mandrel  20  to the position shown in FIG.  14 D. Consequently, all rolls now rest on platform  92 . 
     Next, computer  216  operates a pneumatic cylinder (not shown) to retract pusher plate  274  to the position shown in FIG.  14 E. The signals associated with the foregoing operation of hook  74  and upper mandrel  20  are monitored to verify proper operation. 
     In step  314  computer  216  displays on touch screen  246  a virtual, flashing pushbutton labeled “Cart Down to Unload Rolls.” While this pushbutton is pressed (in the automatic mode the process proceeds without requesting or awaiting a manual signal from an operator), computer  216 , operating through block  234 , lowers platform  92  to the floor as shown in FIG.  14 E. When platform  92  reaches the ground, lower follower wheel  96  (FIG. 11) swings back along spur  100  allowing platform  92  to tilt, so that rolls  10 A- 10 E and  12 A- 12 D will roll off the platform  92 . 
     In step  316 , the air cylinder associated with hook  74  will slide the hook along shaft  76  to the home position next to frame  78 . At this time, computer  216 , operating through block  238 , will pneumatically lift plates  116  and  116 ′ to raise the chucks  118  and  118 ′ into notches  120  and  120 ′ (FIGS. 2 and 5) to reach the positions shown in FIG.  14 E. 
     While the foregoing described a manual shared mode (and indicated the differences from an automatic shared mode), in a manual or automatic discrete mode, the platform can remove rolls from one mandrel and deliver the rolls to the production floor before the platform returns to unload rolls from the other mandrel. As shown in FIG. 15A, platform  92  can support rolls  10 A- 10 E after mandrel  18  is withdrawn. In this case however, rolls  10 A- 10 E are not pushed together but remain separated as shown. Eventually, platform  92  descends to allow rolls  10 A- 10 E to roll onto the production floor. 
     In this discrete mode, the platform  92  now rises to support rolls  12 A- 12 D as shown in FIG.  15 B. Thereafter, mandrel  20  can be withdrawn so that rolls  12 A- 12 D are fully supported on platform  92 . Finally, platform  92  descends to allow rolls  12 A- 12 D to roll onto the production floor. 
     Regardless of the mode (shared or discrete), in step  318  (FIG. 16C) computer  216  will now display on touch screen  246  a virtual, flashing pushbutton labeled “Extend Both Mandrels 90%.” While this pushbutton is pressed, computer  216 , operating through block  228 , will move journals  174  and  174 ′ and mandrels  18  and  20  until reaching a position constituting a 90% extension of the mandrels, as shown in FIG. 14F, at which point the mandrels automatically stop. This 90% extension allows cores  16  to be inserted through the spaces vacated by sliding plates  116  and  116 ′ and onto mandrels  18  and  20 , as shown in FIG.  14 F. 
     In step  320  computer  216  will pause and display on touch screen  246  the message “Operator to Load Cores on Both Upper and Lower Mandrels.” Computer  216  will also display on touch screen  246  a virtual, flashing pushbutton labeled “Operator Procedure Completed.” If this pushbutton is pressed, computer  216  will display in succeeding step  322  (FIG. 16D) a flashing, virtual pushbutton on touch screen  246  labeled “Extend Both Mandrels 100%.” While this pushbutton is pressed (in the automatic mode the process proceeds without requesting or awaiting a manual signal from an operator), computer  216 , operating through block  238 , will lower the supporting plates  116  and  116 ′ to place the chucks  118  and  118 ′ (FIGS. 2 and 5) in alignment with mandrels  18  and  20 . Next, so long as the above virtual pushbutton is pressed, computer  216 , operating through block  228 , will fully extend mandrels  18  and  20  until their distal ends  19  and  21  engage chucks  118  and  118 ′. At this time the mandrels will automatically stop at 100% extension. 
     In succeeding step  324 , computer  216  will display a flashing, virtual pushbutton on touch screen  246  labeled “Retract Web Tail Puller.” If this pushbutton is pressed (in the automatic mode the process proceeds without requesting or awaiting a manual signal from an operator), computer  216 , operating through block  243 , will lower bars  106  and  108  (FIGS.  3  and  4 ). In succeeding step  326 , computer  216  will display a flashing, virtual pushbutton on touch screen  246  labeled “Center Supports Raise.” If this pushbutton is pressed (in the automatic mode the process proceeds without requesting or awaiting a manual signal from an operator), computer  216 , operating through block  232 , will pneumatically rotate lever  65  (FIG. 4) to rotate arms  62  and  68  into position to support the centers of mandrels  20  and  18 . 
     It will be understood that any of the foregoing unloading procedures can be interrupted by depressing the unload sequence stop button  256  (FIG.  13 ). 
     The system will now prepare for a new rewinding phase by resetting various parameters in step  328 . For example, the system will reset the counters associated with registering the amount of web rewound onto the mandrels. Also, the operator can review and alter the various parameters entered into computer memory  218  as described above in connection with step  276 . 
     The operator may now use jog button  250  (FIG. 13) to slowly advance the web and allow the operator to the tape the incoming web to the cores  16 . The operator can then confirm completion of this procedure by pressing a virtual pushbutton displayed on touch screen  246  as indicated in step  330 . The operator can also set the touch rolls  54  and  68  to operate in an automatic mode and direct them to move against the rolls  10  and  12  as indicated in step  332 . 
     Computer  216  will also allow the operator to control various elements through virtual pushbuttons presented on screen  246 . For example, the operator can operate the main brake, position the web guide, and place the web guide in a manual or automatic mode. The web guide is a motor-driven system for axially repositioning the supply roll  22 . The operator will also be given control over the equipment associated with supply roll  22 . Specifically, the operator can operate the chucks supporting the supply roll  22 , as well as adjust the elevation of supply roll  22 . The operator will also be able to select brake pucks that are used with the supply roll  22 . 
     The operator will also be able to specify whether the rewinding proceeds with the cores  16  either slipping or locked into position on the mandrels  18  and by gripping tabs  84  and  86 . The operator can also select the direction of rotation of the mandrels so that the web can approach from above or below. Also, the slitter may produce some trimming waste that can be removed by a vacuum system, which is under the control of the operator. In addition, certain nip rolls can be made active or inactive based on selections by the operator. 
     Once these settings are accomplished and machine interlocks are completely satisfied, the operator can begin the rewinding process of step  334  by pressing “run” pushbutton  248  on panel  244 . Supply roll  22  will then be paid out and web  24  pulled by driven rollers  32  and  36  (FIG.  4 ). Web  24  can then be slit into a number of narrower webs by means of the slitter combination  42 ,  44 . Driven rollers  50  and  56  pull the slitted webs and deliver them over touch rolls  54  and  60  to the rolls  10  and  12 . 
     The operator can also adjust the target speed that should be reached after initial acceleration, by adjusting knob  260  (FIG.  13 ). The operator can also manually adjust the tension of the web as delivered by supply roll  22 , by adjusting knob  262 . 
     Beams  146  (FIG. 7) can be retracted so that the touch rolls  54  and  60  do not produce excessive pressure as the rewinding rolls  10  and  12  grow. By operating motor  136  to rotate pinion  134 , bracket  144  and beam  146  retract with the growth of the rewinding rolls  10  and  12 . Motor  136  is operated intermittently in response to the photo sensor  154  signaling that more room is needed for growth. 
     The pressure asserted by air cylinder  168  (FIG. 8) causes touch rolls  54  and  60  to apply an appropriate pressure to rewinding rolls  10  and  12 . As discussed previously, this touch pressure can vary during the course of the rewinding. In addition to winding with touch rolls  54  and  60  kept in contact with rewinding rolls  10  and  12 , there is an additional mode that maintains a small constant gap between the touch rolls and rewinding rolls (gap mode). Diameter feedback from rolls  10  and  12  is compared to positional feedback for beams  146 , and motor  136  operates to position rolls  54  and  60  accordingly (under these circumstances rolls  54  and  60  are referred to as flanking rolls). There are separate independent systems for operating each beam  146 . In other embodiments, there could be a single central system working in conjunction with beams  146  that are linked to operate together. 
     If an emergency occurs, the operator can stop the rewinding process by depressing button  258  (FIG.  13 ). This will bring the machine to a sudden stop. Thereafter, the operator can depress the “Emergency Stop Reset” button  252  to restore various registers in computer  216  to the pre-stop condition, provided all other safety conditions are met. In less urgent situations, the machine can be stop by pressing “Machine Stop” button  254 . This will cause the machine to decelerate to a controlled stop. 
     As the rewinding rolls  10  and  12  grow, counters inside a computer  216  keep track of the amount of rewinding, awaiting the delivery of a full load onto cores  16 . When the rolls  10  and  12  grow to the desired diameter or web length, computer  216  can automatically decelerate mandrels  18  and  20 . Thereafter, an unloading procedure can be performed as described previously. 
     It is appreciated that various modifications may be implemented with respect to the above described, preferred embodiments. While two mandrels are disclosed, in other embodiments a different number of mandrels may be employed. Also the length of the mandrels as well as the number of cores supported by the mandrels can be different in different embodiments. Additionally, while inflation-operated gripping tabs and locating tabs are shown, in other embodiments the gripping and locating can be performed by other mechanical means. Furthermore, the steps of the flow chart can be performed in an order different than that described above. Moreover, in other embodiments steps can be added or deleted. While various supports are shown for the center and end of the mandrels, in other embodiments a greater or lesser number of supports may be employed. Also, while swinging hooks or arms are shown, other embodiments may employ supports that are moved into a working position linearly. Furthermore, some embodiments may eliminate the sliding plates supporting the chucks for the distal ends of the mandrels in which case, the mandrels may be extended an amount different than 90% when loading the cores. Also, the dimensions, materials, shapes, and locations of the various components described herein may be varied depending upon the desired strength, capacity, clearance, rigidity, etc. 
     Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.