Patent Publication Number: US-6983909-B2

Title: Roll changing apparatus

Description:
FIELD OF THE INVENTION 
     This invention relates to apparatus capable of providing a wound roll of material to a material-handling process. Specifically, the invention relates to apparatus for exchanging a first wound roll of material, particularly a depleted roll of material, or roll remnant, for a second wound roll of material. The invention relates particularly to the handling of rolls of paper web materials. 
     BACKGROUND OF THE INVENTION 
     Web materials are a ubiquitous part of daily life. Materials such as papers, plastic films, and metals may be processed by winding the material into a large roll having a roll core and subsequently unwinding the material from the large roll as a step in a process to convert the material into a finished product. 
     As the rolls of material are wound, a roll may be wound to a particular size and then the winding of the roll is stopped. The finished roll may be removed, an empty core provided and the winding of a subsequent roll begun. 
     During the unwinding of the material, a roll may be unwound until the useable portion of the roll is removed. The roll remnant may be removed, a subsequent roll installed and then unwound. 
     The exchange of a finished roll for a new roll core, or of a roll remnant for a fresh roll, may cause a stoppage of the web handling process. This stoppage may reduce the overall productivity of the process. Time spent by personnel and equipment making this exchange, is time taken away from other tasks. It is desirable to exchange the rolls as quickly and efficiently as possible. Quick and efficient exchanges may increase productivity by reducing the duration of process stoppages and also by reducing the time spent on the exchanges thereby freeing equipment and personnel for other tasks. 
     SUMMARY OF THE INVENTION 
     A roll-handling apparatus of the invention exchanges a roll remnant (remnant) and a full roll of material having a radius of about R. The roll-handling apparatus comprises a dump cradle capable of transitioning between a roll-support position and a roll-release position. The roll-handling apparatus further comprises a roll-transfer surface capable of receiving the remnant from the dump cradle. The roll-transfer surface comprises an extension element. The extension element is capable of transitioning from a retracted position to an extended position. The remnant may be transferred from the dump cradle to the extended position. The extended position may coincide with a roll-removal position. The roll-handling apparatus further comprises a roll-delivery element capable of placing a fresh roll of material on the dump cradle and subsequently removing the remnant from the roll-removal position. 
     In another aspect the apparatus further comprises a trolley capable of transitioning between a roll-loading station and a roll-unwinding station. The trolley may comprise the dump cradle, and roll-transfer surface. 
     The apparatus of the invention may facilitate the delivery of a new roll and the subsequent removal of a remnant during a single trip of the roll delivery element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       While the claims hereof particularly point out and distinctly claim the subject matter of the present invention, it is believed the invention will be better understood in view of the following detailed description of the invention taken in conjunction with the accompanying drawings in which corresponding features of the several views are identically designated and in which: 
         FIG. 1  is a schematic side view of one embodiment of the apparatus of the invention. 
         FIG. 2A  is a schematic perspective view of a roll handled according to one embodiment of the invention. 
         FIG. 2B  is a schematic perspective view of a roll handled according to another embodiment of the invention. 
         FIG. 3  is a schematic plan view of a trolley according to one embodiment of the invention. 
         FIG. 4  is a schematic sectional view of  FIG. 3  taken along section line  4 — 4  of  FIG. 3 . 
         FIG. 5A  is a schematic plan view of a trolley and trolley stations according to one embodiment of the invention. 
         FIG. 5B  is a schematic plan view of two trolley and trolley stations according to another embodiment of the invention. 
         FIG. 5C  is a schematic plan view of a multi-roll trolley and trolley stations according to yet another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description is applicable to the handling of rolls of web material. The nature of the web material is not a limitation of the apparatus. The apparatus may be configured to handle rolls of any web material. The apparatus may be configured to handle paper, polymeric, metal or other web materials. As illustrated in  FIG. 1 , the apparatus  100  comprises a dump cradle  110 , a roll-transfer surface  120 , and a roll-delivery element  130 . The dump cradle  110  is capable of transitioning from a roll-support position  112  to a roll-release position  114 . A roll remnant, or remnant,  280 , may be released by the dump cradle  110  and may be received by the roll-transfer surface  120 . The roll-transfer surface  120  comprises an extension element  122 . The extension element  122  is capable of transitioning from a retracted position  123  to an extended position  125 . The remnant  280  may be transferred to the extended position  125 . The extended position  125  may coincide with a roll-removal position  140 . The roll-delivery element  130  may provide a fresh roll  200  and may place the roll  200  on the dump cradle  110  when the dump cradle  110  is in the roll-support position  112 . The roll-delivery element  130  may subsequently remove the remnant  280  from the roll-removal position  140 . 
     The Roll: 
     The roll  200  may comprise any generally cylindrical roll of web material W wound about a central axis  201 . As illustrated in  FIGS. 2   a  and  2   b  the cylindrical roll  200  has a diameter and a width. The roll  200  has a circumferential surface  222 , and two sides  202 . The roll  200  may be wound on a central shaft  240 , or a hollow core  250 , coincident with the central axis  201  of the roll  200 . Portions of the central shaft  240  or hollow core  250  may protrude beyond the sides  202  of the roll  200 . The hollow core  250  may alternatively be generally flush with the sides  202  of the roll  200 . 
     In one embodiment, rolls  200  having generally flush hollow cores  250  may have core inserts  260 , inserted into the hollow cores  250 . The core inserts  260  may protrude from each of the sides  202  of the rolls  200 . The central shaft  240  and core inserts  260  may provide surfaces for the dump cradle  110  to support. 
     The size of the roll  200  is not a limitation of the apparatus of the invention. The apparatus  100  may be scaled appropriately to handle rolls of any particular dimensions. 
     The Apparatus: 
     The hereinafter described apparatus components may be comprised of metal, wood, glass, composite, or other materials appropriate to the intended use of the component as are known in the art. 
     The Dump Cradle: 
     The dump cradle  110  may comprise a single dump cradle  110  or a plurality of dump cradles  110 . In the embodiments illustrated in  FIGS. 1 ,  3 , and  4 , the dump cradle  110  comprises a pair of dump cradles  110  disposed one at each end of the roll  200 . Each dump cradle  110  is capable of supporting the roll  200  via a surface extending beyond a side  202  of the roll  200 . 
     The dump cradle  110  may be configured to transition between the first roll-support position  112  and the second roll-release position  114  utilizing any means known in the art. In one embodiment, illustrated in  FIG. 1 , the dump cradle  110  may be configured to use the force of gravity to transition between the roll-support position  112  and the roll-release position  114 . In this embodiment, the dump cradle  110  may be maintained in the roll-support position  112  by the presence of a pawl  115  interfering with the movement of the dump cradle  110  to the roll-release position  114 . In this embodiment, the mass of the remnant  280  may act upon a pivot point  116  of the dump cradle  110  to create a torque about the dump-cradle pivot point  116 . The torque may be countered by the presence of the pawl  115  interfering with the rotation of the dump cradle  110  about the pivot point  116 . The dump cradle  110  may also be released from the roll-support position  112  by the use of a cog, a solenoid actuated release, or other means know in the art. 
     The pawl  115  may be withdrawn at the discretion of an operator either manually or automatically, and either locally or remotely. The withdrawal of the pawl  115  enables the dump cradle  110  to rotate in response to the torque created by the presence of the remnant  280  in the dump cradle  110 . 
     The remnant  280  may be released by the dump cradle  110  at a point between the roll-support position  112  and the roll-release position  114 , or the remnant  280  may be released at the roll-release position  114 . When the remnant  280  is released from the dump cradle, the torque associated with the remnant  280  will be removed and the dump cradle  110  may rotate back to the roll-support position  112  by way of an oppositely directed torque arising from the action of gravity upon an appropriately sized and positioned counterweight  117 . The pawl  115  may be repositioned to interfere with the rotation of the dump cradle  110  between the roll-support position  112  and the roll-release position  114  as, or after, the dump cradle  110  returns to the roll-support position  112 . The size and position of the counterweight  117  may be such that the torque associated with the lightest possible remnant  280  is greater than the counterweight torque, and is sufficient to cause the rotation of the dump cradle  110  between the roll-support position  112  and the roll-release position  114 . Other configurations of the counterweight are possible such that the motion of the dump cradle as it transitions between positions is in accordance with the needs of the roll-handling process. 
     In the embodiment illustrated in  FIG. 4 , the dump cradle  110  may be transitioned by the action of a dump-cradle end effector  118 . A single dump-cradle end effector  118  may enable both transitions, or an opposed pair of dump-cradle end effectors  118  may be used to enable the transitions. Exemplary end effectors include, without being limiting, pneumatic or hydraulic cylinders, linear servo motors, linear actuators, a rack and pinion system coupled to a cylinder or a rotary actuator, a belt drive system driven by an electric, hydraulic, or pneumatically powered motor, a system of chains and sprockets, and other means of generating motion as are known in the art. 
     In another embodiment (not shown), the dump cradle may be capable of transitioning from a first roll-receipt position to a second roll-support position to a third roll-release position. The dump cradle may be transitioned between these respective positions by the above described potential or kinetic energy actuators, and/or combinations thereof. 
     The Roll-Engaging Element: 
     The apparatus may comprise at least one roll-engaging element. The roll-engaging element may be adapted to engage the hollow core  250 , central shaft  240 , or core insert  260 , (collectively considered the engaged roll element) of the roll  200 . As shown in  FIGS. 3 and 4 , the engaging element  119  may comprise an actuator shaft  275  capable of engaging the hollow core  250 , or appropriate cavities in the ends of the central shaft  240  or the core inserts  260 . The actuator shaft  275  may comprise splines or a tapered shaft matched with a splined or tapered cavity of the engaged roll element. The actuator shaft  275  may comprise an expanding chuck inserted into the engaged roll element and then circumferentially expanded mechanically, pneumatically, or hydraulically. The actuator shaft  275  may comprise partial, or complete, threads matched to threads in the engaged roll element. The engagement between the actuator shaft and the engaged roll element may be by other means as are known in the art. 
     The engagement of the engaging element  119  and the engaged roll element, may lift the roll  200  from the support of the dump cradle  110  such that the roll  200  is supported by the engaging element  119 . The engaging element  119  may comprise one or more bearing elements  270  capable of supporting the roll  200  as the roll  200  is rotated. These bearing elements  270  may be rotating-element bearings, solid-material bearings, journal bearings, or other types of bearings as are known in the art. The bearing elements may engage and support the roll via the outside surface of central shafts  240  or core inserts  260 . The bearing elements  270  may engage and support the actuator shafts  275  which in turn engage and support the roll  200 . The engaged roll element may also comprise bearing surfaces (not shown) that engage and support the actuator shaft  275  as it engages the engaged roll element. 
     The engaging element  119  may comprise a roll end effector  300 . The roll end effector may be coupled to the actuator shaft  275 . The roll end effector  300  may be electrically, mechanically, hydraulically, or pneumatically rotated to rotate the roll  200 . The roll  200  may be rotated to unwind the material W. Alternatively, the roll  200  may be rotated to wind material W. 
     In another embodiment, the roll  200  may be rotated while held by the dump cradle  110 , or the engaging elements  119 , by a surface winding mechanism (not shown). The surface winding mechanism may contact the circumferential surface  222  of the roll  200  to rotate the roll  200  and unwind the web material W from the roll  200 . 
     The engaging element  119  may be transitioned from a disengaged position  310  to an engaged position  320  and back to the disengaged position  310 . The engaging element  119  may move along at least a portion of the winding axis to engage the roll  200 . The engaging element  119  may move linearly, by rotation, along a path defined by the motion of a cam follower along a cam, and any combination of these, into engagement with the roll  200 . The engaging element  119  may slide along a surface, may move in conjunction with a cylinder, or a rack and pinion system (not shown). The engaging element  119  may move in conjunction with a roll-engaging-element end effector (not shown). Exemplary end effectors include, without being limiting, pneumatic or hydraulic cylinders, linear servo motors, linear actuators, a rack and pinion system coupled to a cylinder or a rotary actuator, a belt drive system driven by an electric, hydraulic, or pneumatically powered motor, a system of chains and sprockets, and other means of generating motion as are known in the art. 
     In an embodiment where the engaging element  119  engages a core insert  260 , the disengaging of the engaging element  119  from the core insert  260 , may be problematic. The transition of the engaging element  119  from the engaged position  320  to the disengaged position  310 , may cause the core insert  260  to at least partially disengage from the hollow core  250 . In the embodiment, illustrated in  FIG. 4 , the core insert  260  comprises an ejector  700  capable of exerting a force in opposition to the withdrawal of the engaging element  119 . The exertion of this force may maintain the engagement of the core insert  260  with the hollow core  250 . 
     The ejector  700  may comprise a spring actuated system. As shown in  FIG. 4 , a spring  710  is constrained between a base  720  and a cap  730 . The cap  730  is configured to contact the engaging element  119  as the engaging element  119  is inserted into the cavity  268  of the core insert  260 . The motion of the engaging element  119  into the cavity  268 , compresses the spring  710 . As the engaging element in withdrawn from the cavity  268 , the expansion of the spring  710  functions to disengage the engaging element  119  from the cavity  268  and to forcibly maintain the core insert  260  in engagement with the hollow core  250 . In this embodiment, the spring may be any compression spring capable of decoupling the engaging element  119  from the cavity  268 . The base  720  and the cap  730  may be cast or machined from any material capable of enduring the stresses of the ejection. Appropriately selected woods, polymers, or metals may be used for the cap  730  and the base  720 . Ultra-high-molecular-weight plastic is a non-limiting example of a material suitable for the cap  730  and the base  720 . 
     In an alternative embodiment (not shown) the ejector  700  may comprise a pneumatic cylinder wherein the cylinder is compressed as the engaging element  119  engages the core insert  260 , and the cylinder extends as the engaging element  119  is withdrawn. The cylinder in this embodiment may be actively powered or may be a sealed cylinder relying upon the expansion of the previously compressed gas to extend the cylinder to eject the engaging element  119 . 
     Other means of generating a reactive force in opposition to the withdrawal of engaging element  119  as are known in the art may be used to maintain the engagement of the core insert  260  with the hollow core  250 . 
     The Roll-Transfer Surface: 
     When the dump cradle  110  transitions to the roll-release position  114 , the remnant  280  may be released by the dump cradle  110  and received by the roll-transfer surface  120 . The roll-transfer surface  120  defines a roll-transfer path P. The remnant  280  travels along the roll-transfer path P proceeding from the dump cradle  110  to a roll-removal position  140 . The roll-transfer surface  120  may comprise a single surface or a plurality of surfaces across the width of the remnant  280 , and along the length of the roll-transfer path P. The roll-transfer surface  120  may be configured to support the entire circumferential surface  222  of the remnant  280  or only a portion of the surface. The roll-transfer surface  120  may be configured to support only the portions of the remnant  280  extending beyond the sides  202  of the web material W of the remnant  280 . 
     The roll-transfer surface  120  may proceed at a decline over at least a portion of the roll-transfer path P from the dump cradle  110 , to enable the remnant  280  to move along the roll-transfer path P due to gravitational forces. The roll-transfer surface  120  may comprise one or more powered conveying surfaces (not shown) capable of transferring the remnant  280  from the dump cradle  110  to the roll-removal position  140 . With this option, the roll-transfer surface  120  may decline from the dump cradle  110 , may incline from the dump cradle  110  may be level with the dump cradle  110 . 
     The roll-transfer surface  120  may comprise one or more roll-contacting surfaces  124  which contact at least a portion of the roll  200  or a surface protruding from the sides  202  of the roll  200 . The roll-contacting surfaces  124  may be comprised of any material suitable for the efficient transfer of the rolls  200  along the roll-transfer path P. Any, or all, of the roll-contacting surfaces  124  of the roll-transfer surface  120  may be surface hardened, coated with a high wear coating, such as a plasma coating or a chromium coating, or prepared by other means known in the art for extending the service life of a wear surface. The roll-contacting surfaces  124  may comprise a sacrificial wear element (not shown) capable of easy replacement and intended to efficiently transfer the remnant  280 . A low friction ultra-high-molecular-weight polymeric material, and a steel wear strip are non-limiting examples of sacrificial wear elements. 
     The roll-transfer surface  120  may comprise an extension element  122  capable of transitioning from a retracted position  123  to an extended position  125 . The terms extended and retracted are not to be construed as limiting the motion of the extension element  122  to a reciprocal motion. The terms refer to an extension of the roll-transfer path P. The roll-transfer path P is lengthened as the extension element  122  transitions to the extended position  125  and shortened as the extension element  122  transitions to the retracted position  123 . 
     The extension element  122  may comprise a single roll-contacting surface or a plurality of roll-contacting surfaces. The extension element  122  may be configured to contact all or only a portion of the remnant  280  or the surfaces protruding from the sides  202  thereof. The extension element may comprise the above described roll-contacting surfaces  124 . 
     In one embodiment (not shown), the extension element  122  may be transitioned between the retracted position  123  and the extended position  125  by way of gravity. The design of the extension element  122  may provide for the transition from the retracted position  123  to the extended position  125  by gravity acting upon the remnant  280  in conjunction with the extension element  122  to instigate the transition. The subsequent removal of the remnant  280  from the extension element  122  would instigate the transition to the retracted position  123  by the action of gravity upon an appropriate counterweight. 
     Returning to the embodiment, illustrated in  FIG. 1 , the extension element  122  may be transitioned between the retracted position  123  and the extended position  125  by the use of one or more end effectors  129 . A single end effector  129  may enable both transitions, or an opposed pair of end effectors  129  may be used to enable the transitions. Exemplary end effectors include, without being limiting, pneumatic or hydraulic cylinders, linear servo motors, linear actuators, a rack and pinion system coupled to a cylinder or a rotary actuator, a belt drive system driven by an electric, hydraulic, or pneumatically powered motor, a system of chains and sprockets, and other means of generating motion as are known in the art. 
     The roll-transfer surface  120  may further comprise one or more roll stops  128 . Roll stops  128  are capable of limiting the motion of the remnant  280  along the roll-transfer surface  120 . The roil stops  128  may be positioned at the portion of the roll-transfer surface  120  furthest from the dump cradle  110 . The roll stops  128  may comprise a cushioned stop comprising a shock-absorbing cylinder, shock-absorbing foam, spring loaded stops, or other impact absorbing elements. The roll stops  128  may also comprise a fixed stop with little shock-absorbing capability, and/or other motion inhibiting means as are known in the art. 
     In one embodiment, the roll-transfer surface  120  may receive the remnant  280  from the dump cradle  110  when the extension element  122  is in the retracted position  123 . The remnant  280  may proceed along the roll-transfer surface  120  stopping at the roll stop  128 . The roll-transfer surface  120  may then extend as described, carrying the remnant  280  with it to the extended position  125 . 
     In an alternative embodiment, the roll-transfer surface  120  may extend prior to the transfer of the remnant  280  from the dump cradle  110  to the roll-transfer surface  120 . In this embodiment, the remnant  280  may proceed along the roll-transfer path P from the dump cradle  110  to the extended position  125  of the extension element  122 . In another embodiment, the extension element  122  may transition from the retracted position  123  to the extended position  125  as the remnant  280  is proceeding along the roll-transfer surface  120 . 
     The position of the remnant  280  at the roll stop  128  when the extension element  122  is in the extended position  125  may coincide with the roll-removal position  140 . In the embodiment illustrated in  FIG. 1 , the extended position  125  may allow the remnant  280  to move a distance greater than the radius R of the subsequent roll  200  from the dump cradle  110 . The dump cradle  110  may be repositioned to the roll-support position  112  after the remnant  280  has been released from the dump cradle  110 . The disposition of the remnant  280  at a roll-removal position  140 , more than the radius R from the dump cradle, enables the roll-delivery element  130  to dispose a subsequent roll  200  onto the dump cradle  1110 , prior to removing the remnant  280  from the roll-removal position  140 . 
     In an alternative embodiment (not shown) the remnant  280  may proceed beyond the extended position  125  of the extension element  122  to a roll-removal position  140  further from the dump cradle  110 . In this embodiment, the extension element  122  provides a retractable bridge between portions of the roll-transfer surface  120  enabling the transit of the remnant  280  from one portion to the next and ultimately to the roll-removal position  140 . 
     The distance D between the roll-removal position  140  and the dump cradle  110  will determine the maximum diameter remnant  280  that may be transferred to the roll-transfer surface while still providing sufficient space in the apparatus  100  for the disposition of a new roll  200  of radius R on the dump cradle  110 . The distance D−R will limit the size of the remnant  280  that can be transferred. The specific configuration of the apparatus will determine how the distance D−R relates to the maximum remnant  280  size.  FIG. 1  illustrates as an example, a roll-transfer surface  120  configured with roll-contacting surfaces  124  that contact the central shaft  240  and not the material W of the remnant  280 . For this configuration, the Distance D−R will accommodate a remnant  280  having a central shaft  240  radius of r and an overall radius of S up to the limit where r+S=D−R. It is possible to configure the apparatus such that the distance D is greater than the distance r+2R. This configuration would permit a full roll  200  to be released as a remnant  280  and still provide sufficient space for the disposition of a subsequent roll  200  prior to the removal of the full roll remnant. 
     The above described configuration is not limited to the handling of rolls wound on a central shaft. Rolls  200  wound on a hollow core  250  may be accommodated up to the limit that the radius r of the component in contact with the roll-transfer surface and roll stop satisfies the equation r=D−R−S. 
     The Trolley: 
     As shown in  FIGS. 3 and 4 , the dump cradle  110 , engaging element  119 , and roll-transfer surface  120  may comprise portions of a trolley  400 . As shown in  FIG. 5A , the trolley  400  may be capable of transitioning from a first roll-loading location  410  to a roll-unwinding location  420 . In another embodiment shown in  FIG. 5B , two trolleys may be disposed such that the first trolley  400  transitions between a first roll-loading location  410  and the roll-unwinding location  420 , and a second trolley  401  transitions between a second roll-loading location  411  and the roll-unwinding location  420 . In this embodiment, the first trolley  400  receives a roll  200  at the first roll-loading location  410 . The first trolley  400  transitions from the first roll-loading location  410  to the roll-unwinding location  420  and the roll  200  is unwound. The second trolley  401  receives a roll  200  of material at the second roll-loading location  411 . The first trolley  400  moves from the roll-unwinding location  420  to the first roll-loading location  410  to exchange the remnant  280  of the first roll  200  for a subsequent fresh roll  200  of material. The second trolley  401  moves from the second roll-loading location  411  to the roll-unwinding location  420  and the second roll  200  is unwound. The trolleys  400 ,  401  alternate between their respective roll-loading locations  410 ,  411  and the roll-unwinding location  420 . 
     In another embodiment, shown in  FIG. 5C , a single trolley  500  may comprise two roll-handling stations  505  and  515 . In this embodiment, a first roll-handling station  505  may be present at the first roll-loading location  510  when the second roll-handling station  515  is present at the roll-unwinding station  520 . When the trolley  500  transitions, the first roll-handling station  505  may move to the roll-unwinding location  520 , the second roll-handling station  515  may move to the second roll-loading location  511  and may exchange a remnant  280  for a fresh roll  200 . After the roll  200  in the first roll-handling station  505  has completed processing, the trolley  500  may transition such that the second roll-handling station  515  moves from the second roll-loading location  511  to the roll-unwinding location  520 . Either one, or both, trolley roll-handling stations may comprise any of the above described remnant-handling elements and combinations thereof. 
     The general operation of a roll-handling trolley with respect to the motion enabling devices for the trolley is well known in the art and will not be further discussed. 
     The Roll-Delivery Element: 
     Returning to  FIG. 1 , the roll-delivery element  130  may operate at least partly above the dump cradle  110  and roll-transfer surface  120 . The roll-delivery element  130  may be of any design capable of effectively disposing a fresh roll  200  onto the dump cradle  110  and removing the remnant  280  from the roll-removal position  140 . The roll-delivery element  130  may comprise a portion of an overhead gantry crane having an appropriate maximum weight limit. The roll-delivery element  130  may pick up a fresh roll  200  at a roll-storage location (not shown). The roll-delivery element  130  may convey the roll  200  vertically from the roll-storage location and then horizontally to the dump cradle  110 . The roll-delivery element may then convey the roll  200  vertically into the dump cradle  110 . The roll-delivery element  130  may subsequently remove the remnant  280  vertically from the roll-removal position  140 . The general operation of a roll-delivery element  130 , with respect to the motivational aspects of the element, is well known in the art and will not be further discussed. 
     The roll-delivery element  130  may be adapted to engage the engaged roll element of the roll  200 . The roll-delivery element  130  may comprise a double hook  136 . The double hook  136  enables the roll-delivery element  130  to dispose a roll  200  on the dump cradle  110  and subsequently pick up a remnant  280  from the roll-removal position  140  without the necessity of first passing the roll-removal position  140  and then returning to the roll-removal position  140 . 
     System Control: 
     In one embodiment, the apparatus  100  may be controlled manually by a human operator. In this embodiment, the operator may control the initiation of each step of the operation of the apparatus. The operator may further control the cessation of each step and the successive initiation of any subsequent step. The operator may control the apparatus through the use of locally or remotely situated controls. 
     In another embodiment, the performance of any of the steps described above including without limitation: providing a fresh roll  200  at the dump cradle  110 , removing the remnant  280  from the roll-removal position  140 , transitioning extension element  122  of the roll-transfer surface  120  between an extended position  125  and a retracted position  123 , transitioning the dump cradle  110  between a roll-support position  112  and a roll-release position  114 , and transitioning a trolley  400  between a roll-loading location  410  and a roll-unwinding location  420 , may be at least partially automated. Sensors may be provided to indicate the position of the roll-delivery element  130 , the dump cradle  110 , the extension element  122  of the roll-transfer surface  120 , the engaging element  119 , the trolleys  400 ,  401 ,  500 , and combinations thereof. Additional sensors may be provided to indicate the position of the end effectors associated with the roll-delivery element  130 , the dump cradle  110 , the extension element  122  of the roll-transfer surface  120 , the engaging element  119 , the trolleys  400 ,  401 ,  500 , and combinations thereof. 
     These sensors may be configured to continuously provide the location of the respective sensed component. The sensors may also be configured to provide discrete inputs when the sensed components have reached predetermined locations. The input provided by the sensor for a given component may be reconciled with the input provided by the sensor for the end effector corresponding to that component and/or the desired location for the given component provided from a control program. This reconciliation may enhance the safe operation of the machine. As an example, the input from the sensor for the dump-cradle end effector  118  of the dump cradle  110  may be referenced against the input value from the sensor for the dump cradle  110 , and with the desired value for the position of the dump cradle  110  from the control program. In the event that the input values and control program do not agree, within an appropriately selected time window, the progress of the roll-handling equipment may be halted until the source of the disagreement may be identified and corrected. A predetermined time window for the reconciliation of the inputs and desired value may be utilized to reduce the occurrence of false indications of disagreement resulting from differences in sensor response times. 
     The above described sensors may be configured to best suit the motion of the particular component. By way of example and without being limiting: the dump cradle  110  may have a rotary motion between its respective positions and therefore a rotary encoder may be used to determine the position of the dump cradle  110 . Linear position sensors may be used to provide the location of elements including the extension elements and the trolley. In one embodiment, sensors may be used to provide an indication of position associated only with each extreme position of the particular component. As a non-limiting example, a sensor may provide the location of the extension element  122  of the roll-transfer surface  120  only when the extension element  122  is in the retracted position  123  or in the extended position  125 . In this embodiment, sensors may provide an input corresponding to the presence of the dump cradle  110  in each of the roll-support  112  and roll-releasing positions  114  but nowhere else. Also in this embodiment, the sensors may provide inputs corresponding to the location of the trolley  400  when the trolley  400  is disposed at either the roll-loading location  410  or at the roll-unwinding location  420 . The sensors may provide inputs to a controller configured to automatically sequence the steps of providing a roll  200 , removing a remnant  280 , transitioning the trolley  400  and unwinding the roll  200 . 
       FIG. 1  illustrates the placement of sensors to indicate the position of specific components. According to the figure, the extension-element-end-effector position sensor  825  indicates the position of the extension-element end effector  129 . The extension-element position sensor  820  indicates the position of the extension element  122 . The roll-delivery-element position sensor  850  indicates the position of the roll-delivery element  130 . The trolley position sensor  830  indicates the position of the trolley  400 . 
       FIG. 4  illustrates an exemplary placement of the dump-cradle position sensor  810 , the dump-cradle-end-effector sensor  815 , and the engaging-element position sensor  840  to provide indications of the dump cradle, the dump-cradle end effector, and the engaging element  119  respectively. 
     Additional sensors (not shown) may be provided to indicate other operational parameters such as the presence of a roll at a particular location, or the diameter of a roll during processing or during handling. The use of such sensors is well known in the art and will not be further discussed herein. 
     The above described sensors may communicate with one or more process controller (not shown). This communication may be by any means known in the art for communicating sensor information to a controller. Non-limiting examples of the communication means include hardwiring the output of the sensor to an input circuits of the controller, providing wireless link between the sensor and the controller, providing a multiplexed signal link between the sensor and the controller. 
     One or more display panels (not shown) may be adapted to provide textual and graphical information regarding the operation of the apparatus. As a non-limiting example, a graphic representation of the apparatus may be provided. The graphic representation may include real time input data as to the location of each component of the apparatus and also information relating to an associated web processing process. Color variations and the use of flashing graphic elements, as are known in the art, may be employed to provide additional information to a machine operator. As a non-limiting example, a flashing green image may be used to indicate that a trolley is transitioning from a roll-loading location to a roll-unwinding location. A red graphic may indicate a component e.g. a trolley, which should be moving, or should be at a location specified by the control program, but is not in the desired state according to the input value. 
     Light stacks (not shown) as are known in the art may be provided to enable a determination of the operation of the apparatus from a distance, or from locations where the display panel cannot be viewed accurately, if at all. These light stacks may use a combination of light color and operation to convey status information. A continuously lit green light may be used to indicate normal safe operation. A flashing green light may indicate that the apparatus is waiting on the downstream process. A flashing red light may indicate that an apparatus safety sensor has been activated. In this manner a considerable amount of information may be provided to a process operator in an efficient manner. 
     EXAMPLE 1 
     An apparatus for handling parent rolls of paper web material, the parent rolls having a diameter of about 100 inches (254 cm). Core plugs having stub shafts are inserted into each end of the core of the roll at a roll-storage location. The roll is transported from the roll-storage location to a position above a roll-loading location of a trolley. The trolley moves from a roll-unwinding location to the roll-loading location when the operator desires to change the remnant supported on the trolley. 
     As the trolley moves, engaging elements retract from a position of engagement with the core plugs of the remnant. Ejectors in the core plugs assist the disengagement of the engaging element from the core plugs. As the engaging elements are withdrawn, the remnant is lowered onto a pair of dump cradles. 
     A first sensor detects the position of the engaging elements to ensure that engaging elements are clear of the remnant. A second sensor detects the diameter of the remnant. Remnants having a diameter of less than 36 inches (91.4 cm) may be transferred to the roll-transfer surface. Larger remnants are precluded from being transferred to the roll-transfer surface due to the diameter capacity of the particular apparatus. 
     For remnants having diameters less than 36 inches (91.4 cm) the operator actuates the dump-cradle end effector to transition the dump cradles. The dump cradles change from the roll-support position to the roll-release position. The remnant is transferred from the dump cradles to the roll-transfer surface. The dump cradles are transitioned back to the roll-support position after the release of the remnant. 
     The remnant moves along the roll-transfer surface to the roll stop. After the remnant has reached the roll stop, an operator actuates an extension-element end effector to extend the extension element of the roll-transfer surface. The extension element and the remnant move to the roll-removal position. 
     The roll-delivery element disposes a new roll into the dump cradles. The engaging elements move into engagement with the roll lifting it from the support of the dump cradles. The roll-delivery element subsequently proceeds to the roll-removal position and removes the remnant. The extension element retracts and the trolley transitions to the roll-unwinding location. The roll-delivery element conveys the remnant to a remnant-handling station and then proceeds to the roll-storage location to pick up another new roll. 
     EXAMPLE 2 
     On command from a controller, a roll-delivery element picks up a new roll from a roll-storage location. The roll-delivery element conveys the roll to a position above a roll-loading station. A first sensor continuously inputs the position of the roll-delivery element to the controller. The motion of the roll-delivery element is stopped when the first sensor indicates that the roll has been conveyed to the roll-loading station. 
     An active roll having a hollow core is disposed in a pair of dump cradles on a trolley. The core of the roll is engaged by a pair of core insert stub shafts that protrude from the sides of the roll. The stub shafts are engaged and supported by a pair of retractable bearing elements capable of supporting the roll during axial rotation of the roll. A second sensor continuously inputs the position of the dump cradles to the controller. A third sensor continuously inputs the position of the retractable bearing elements to the controller. As the active roll is unwound, the diameter of the roll is reduced. A roll-diameter sensor determines the diameter the active roll. The unwinding of the active roll stops after the diameter of the active roll is determined to be at or below a predetermined threshold diameter. 
     On command from the controller, the trolley transitions from the roll-unwinding station to the roll-loading station. The position of the trolley is continuously input to a controller from a trolley-position sensor. The motion of the trolley is stopped when the trolley-position sensor indicates that the trolley is located at the roll-loading station. 
     The controller commands the bearing-elements end effector to retract the bearing elements from the stub shafts of the core inserts until the input from the third sensors indicates&#39; that the bearing elements have transitioned to the retracted position of the bearing elements. As the bearing elements retract, the remnant is lowered to and supported by the pair of dump cradles. 
     The dump cradles transition from the roll-support position to a roll-release position by the action of a dump-cradle end effector at the command of the controller. The action of the dump-cradle end effector is halted when the second sensors indicate that the dump cradles have reached the roll-release position. The remnant of the roll transitions from the dump cradles to a roll-transfer surface. A dump-cradle roll-detecting sensor provides an input to the controller indicating that no roll is present in the dump cradle. The controller then provides an output to the dump-cradle end effector to reverse the motion of the end effector and to transition the dump cradle from the roll-release position to the roll-support location. 
     The remnant rolls along a declining roll-transfer surface stopping at a pair of roll stops situated in line with the stub shafts of the core inserts. A roll-stop roll-detection sensor provides an input to the controller indicating the presence of the remnant at the roll stops. The controller commands the extension-element end effector to transition the extension element from a retracted position to an extended position. The motion of the extension element is halted when the extension-element position sensor indicates that the extension element has reached the extended position. 
     The controller commands the roll-delivery element to deposit the new roll into the dump cradles. The roll-delivery element lowers the new roll from a position above the roll-loading station into the dump cradles. The presence of the new roll is detected by the dump-cradle roll-detection sensor. The downward motion of the roll-delivery element continues after the roll is detected in the dump cradles for a predetermined amount of time until a roll-engaging element of the roll-delivery element has disengaged the stub shafts of the core inserts of the new roll. 
     The roll-delivery element transitions horizontally, at the command of the controller, from the roll-loading station to the roll-removal position. Once the roll-delivery-element-position sensor indicates to the controller that the roll-delivery element is located at the roll-removal position, the roll-engaging element of the roll-delivery element is raised to engage the remnant. The roll-engaging element continues to rise until a predetermined time delay has expired, a roll-delivery-element-roll-engaging-element-position sensor indicates that the roll-engaging element has reached the upper limit of its travel, or until a roll-delivery-element roll-detection sensor indicates the presence of the remnant at a predetermined location. This motion removes the remnant from the roll-removal position. 
     The roll-stop roll-detection sensor indicates to the controller that the remnant has been removed from the roll-removal position. After a predetermined time delay to provide time for the roll-delivery element to lift the remnant clear of the roll stop, the controller commands the extension-element end effector to transition the extension element from the extended position to the retracted position. The motion is halted when the extension-element-position sensor indicates that the extension element has reached the retracted position. 
     After the extension-element-position sensor indicates that the extension element has reached the retracted position, the controller commands the trolley to transition from the roll-loading station to the roll-unwinding position. The motion of the trolley is halted when the trolley-position sensor indicates that the trolley has reached the roll-unwinding position. 
     All documents cited in the Detailed Description of the invention are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention. 
     While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of the invention.