Patent Publication Number: US-6213423-B1

Title: Self-lifting shaftless unwind stand

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to a machine for unwinding material from a previously wound roll and, more particularly, to an improved machine onto which rolls of material can be loaded in preparation for unwinding and then quickly and easily rotated into an unwinding position when a previous roll has been unwound. 
     BACKGROUND OF THE INVENTION 
     Many products are manufactured from elongated sheet or stock material that is shipped and stored in the form of a roll or coil. Continuous strips or webs of thin, flexible material are commonly provided on storage rolls that are subsequently unwound for production of items made from these materials. Examples of these materials are plastic film, metal foil, and paper. Other materials such as cable or wire are also wound onto rolls. 
     During the manufacture of paper products such as napkins, newspapers, and magazines, for example, very large storage rolls of paper are used to provide the stock material from which the paper items are produced. The storage rolls are then unwound for further processing such as cutting, folding, or printing. 
     When a coiled roll is being unwound so that the material can be further processed, it is desirable to quickly change to a new roll once the previous roll is spent. However, the large and heavy storage rolls of stock material are difficult to handle. Also, the manufacturing process must be stopped so that the spent roll can be removed and replaced by a new roll. The time spent unloading and reloading the machine results in decreased production of the final product. 
     A machine that can accept subsequent or stand-by rolls of stock material that are ready to be moved quickly into an unwinding position is highly desirable because of the savings in time that such a machine would provide. The stand-by roll can be quickly moved into place, and the unwinding and subsequent processes can proceed with minimal interruption. 
     The placement of a roll of material onto a shaft or spindle which is then mounted onto a machine for unwinding of the roll is another time-consuming manufacturing step. The added steps of inserting the shaft into the core of the roll and then removing it when the roll is unwound result in additional time spent setting up the machine which also decreases production. A machine that can hold and unwind a roll of material without using a shaft or spindle would be advantageous. 
     Thus, there continues to be a need for a method and apparatus for unwinding material from a roll that allows the loading of subsequent rolls of material which are then quickly rotated into position for unwinding. Also, there is a need for a method and apparatus that will increase the speed of the unwinding process by eliminating time-consuming steps, thus increasing productivity. The present invention meets these desires. 
     SUMMARY OF THE INVENTION 
     A roll unwinding machine embodying the present invention performs lifting and turning operations on a roll of material in order to unwind the material from the roll. 
     The material on the roll may be a thin flexible web of material such as foil, plastic film, fabric, or paper. Alternatively, the material may be an elongated strip or length of material such as, for example, wire, cable, string, or rope. For simplicity of explanation, references herein to paper as the material on the roll should be construed to include any material capable of being wound onto a roll and subsequently unwound. 
     The unwinding machine of the present invention comprises a base with a turret shaft extending vertically from the base. A turret bearing ring is coaxially and rotatably disposed around the turret shaft. In the preferred embodiment described herein, more than one turret bearing ring can be provided. 
     A lift arm assembly is provided for lifting and rotatably holding the roll of material. The lift arm assembly is pivotally connected to the turret bearing ring and is movable around the turret shaft in conjunction with the turret bearing ring. In the preferred embodiment described herein, the lift arm assembly moves between first and second positions around the turret shaft. 
     In the preferred embodiment, the loading and unwinding operations take place at first and second positions, respectively, around the turret shaft. The first and second positions, however, are interchangeable with respect to the operation performed at each position. The terms “first” and “second” are used for descriptive purposes herein in reference to the relative positions of the lift arm assembly as it rotates around the turret shaft. 
     More than one lift arm assembly may be provided in the preferred embodiment of the present invention. When additional lift arm assemblies are provided, a subsequent roll (or rolls) can be loaded onto the machine in advance of being unwound. While a roll is in the process of being unwound, a subsequent roll can be loaded onto the machine and held at a waiting position until the previous roll is fully unwound. The subsequent roll is then moved into the unwinding position after the core of the previously unwound roll is moved out of the unwinding position. 
     The lift arm assembly includes two generally parallel lift arms which accept and support the roll of material during loading and unwinding operations, respectively. Each lift arm of the lift arm assembly has a first end for supporting the roll and a pilot bearing at the first end. Each lift arm also includes a second end that is operably associated with a lift arm track. The lift arms are horizontally movable relative to each other along the lift arm track. In operation, the lift arms move away from each other to accept the roll during loading of the roll onto the machine. The lift arms then move toward each other to releasably and rotatably hold the roll between the pilot bearings. The lift arms support the roll during turning of the roll to unwind the material. 
     A guide cam is located around the turret shaft. The guide cam includes an outer rim around its periphery for supporting the lift arm assembly while the lift arm assembly moves around the turret shaft between first and second positions. 
     A support beam extends from the lift arm track toward the guide cam. The support beam has a distal end with a cam yoke roller at the distal end. The cam yoke roller cooperates with the outer rim to support the lift arm assembly during its movement around the turret shaft. 
     A lifting mechanism is provided in the preferred embodiment. The lifting mechanism is operably associated with the cam yoke roller to raise and lower the lift arm assembly between an up position and a down position. The roll is loaded onto the machine when the lift arm assembly is in the down position. The roll is then raised to the up position, moved around the turret shaft into the unwinding position and then unwound, as described below. 
     The preferred embodiment described herein further comprises a drive tower extending upwardly from the turret shaft. The drive tower includes the mechanism for turning the roll to unwind the material therefrom once it has been loaded and moved into the unwinding position. A tower frame, a turning belt, a drive for rotating the turning belt, a belt frame, a belt frame axle, an upper roller, and a lower roller are the components of the drive tower that are employed during the turning of the roll of material. 
     The tower frame has generally vertical first and second side walls, an upper portion, and a lower portion. The lower portion includes a bracket that extends between the first and second side walls and provides a mount for the tower frame to the turret shaft. The belt frame axle extends through the first and second side walls of the tower frame adjacent to the upper portion. 
     The belt frame includes a first member, a second member, a free end, and an axle end. The first and second members are located between the first and second sides of the tower frame. The axle end of the belt frame is pivotally attached to the belt frame axle, and the free end of the belt frame is adjacent to the lower portion of the tower frame. The free end of the belt frame is free to swing away from the tower frame as the belt frame pivots around the belt frame axle at the upper portion of the tower frame. 
     The upper and lower rollers are both disposed between the first and second members of the belt frame. The upper roller is coaxial with the belt frame axle, and the lower roller is adjacent to the free end of the belt frame. 
     The turning belt extends around the upper and lower rollers and has a contact surface for frictionally contacting the roll and driving the roll. The belt frame is pivoted at the belt frame axle such that the free end of the belt frame extends outwardly from the tower frame and toward the roll being held by the lift arm assembly. When the rotating turning belt contacts the roll, the roll is rotated, thereby unwinding the material therefrom. 
     In operation, the lift arm assembly is initially placed at the first position and a roll of material is placed between the lift arms which are moved apart to accept the roll. The lift arms are then moved toward each other to hold the roll between the pilot bearing on the lift arms. The roll is then lifted by the lift arm assembly which then moves to the second position where the roll will be unwound. The free end of the belt frame is then pivoted away from the drive tower and toward the roll until the turning belt contacts the roll. As the turning belt rotates, it frictionally turns the roll to unwind the roll. As the material on the roll is unwound, the diameter of the roll decreases, and the free end of the belt frame is further pivoted so as to keep the belt in continuous contact with the roll until unwinding is complete. 
     There are other advantages and features of the present invention which will be more readily apparent from the following detailed description of the preferred embodiment of the invention, the drawings, and the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings, 
     FIG. 1 is a front view of an unwinding machine embodying the present invention; 
     FIG. 2 is a side view of the unwinding machine showing a roll of material being turned to unwind the material therefrom; 
     FIG. 3 is a top plan view of the unwinding machine showing a roll being loaded onto the machine and a roll at the unwinding position; 
     FIG. 4 is a partial top plan view of a lift arm assembly of the unwinding machine of FIG. 2 taken along line  4 — 4  of FIG. 2; 
     FIG. 5 is a front view of the lift arm assembly of FIG. 4 taken along line  5 — 5  of FIG. 4; 
     FIG. 6 is a partial cutaway, top plan view of a guide cam of the unwinding machine of FIG. 1 taken along line  6 — 6  of FIG. 1; 
     FIG. 7 is an enlarged partial view of the unwinding machine showing a lifting mechanism of the unwinding machine with the lift arm assembly in a down position; and 
     FIG. 8 is an enlarged partial view of the unwinding machine showing a lifting mechanism of the unwinding machine with the lift arm assembly in an up position. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The invention disclosed herein is, of course, susceptible of embodiment in many different forms. Shown in the drawings and described hereinbelow in detail are preferred embodiments of the invention. It is to be understood, however, that the present disclosure is an exemplification of the principles of the invention and does not limit the invention to the illustrated embodiments. 
     For ease of description, a machine embodying the present invention is described hereinbelow in its usual assembled position as shown in the accompanying drawings and terms such as upper, lower, horizontal, longitudinal, etc., may be used herein with reference to this usual position. However, the machine may be manufactured, transported, sold, or used in orientations other than that described and shown herein. 
     Referring to FIGS. 1-8, an unwinding machine  30  embodying the present invention provides a self-lifting, driven, shaftless unwind stand for lifting, moving, and unwinding a roll  31  of previously wound material  32 . The roll  31  can include a hollow, cylindrical core  33  around which the material  32  is wound. 
     The unwinding machine  30  of the present invention preferably comprises a generally flat, horizontal base  34  with a cylindrical turret shaft  36  extending upwardly from the base  34 . As shown in FIGS. 1 and 2, the machine  30  also includes a guide cam  40 , described in detail below, mounted on a plurality of supports  42  above and generally parallel to the base  34 . The turret shaft  36  of the preferred embodiment is mounted to the top  41  of the guide cam  40  and extends vertically therefrom. 
     A turret bearing ring  50  is coaxially and rotatably disposed around the turret shaft  36 . The turret bearing ring  50  is generally cylindrical with a protrusion  52  radially extending from the turret bearing ring  50 . The protrusion  52  is provided so that a lift arm assembly  60 , described in detail below, can be connected or mounted to the turret bearing ring  50  at a mounting point  54  on the protrusion  52 . Preferably, the mounting point  54  is adapted to provide a pivot point for the lift arm assembly  60 . 
     The turret bearing ring  50  rests on a collar  38  at the bottom of the turret shaft  36 . The collar  38  is preferably coaxial with and fixedly attached to the turret shaft  36  and has an outer diameter larger than the inner diameter of the turret bearing ring  50  which rests on top of the collar  38 . 
     The turret bearing ring  50  can include any type of suitable bearing configuration known in the art which allows relatively free rotation of the turret bearing ring  50  around the turret shaft  36 . 
     A drive system of any suitable type known in the art can be employed to rotate the turret bearing ring  50 . For example, the turret bearing ring  50  can be rotated by a belt or chain  53  operably connected to a drive such as a motor  55 , shown schematically in FIG.  3 . Alternatively, a suitable gear system can be configured to rotate the turret bearing ring  50 . 
     In the preferred embodiment described herein and as shown in FIGS. 1 and 2, more than one turret bearing ring  50  can be provided. In such a case, the turret bearing rings  50 ,  50 ′ are stacked on the turret shaft  36 , and the protrusions  52  are configured such that the mounting points  54  of each turret bearing ring  50  are at substantially the same vertical height with respect to the guide cam  40 . For example, protrusion  52 ′ extends radially and upwardly because the turret bearing ring  50 ′ from which it extends is the lower of the two turret bearing rings in the embodiment shown in FIGS. 1 and 2. 
     The lift arm assembly  60  is provided for lifting and rotatably holding the roll  31  of material. In the preferred embodiment, the lift arm assembly  60  is pivotally connected to the turret bearing ring  50  such that the lift arm assembly  60  is pivotable between an up position  63  (FIGS. 1,  2  and  8 ) and a down position  65  (FIG.  7 ). Also, the lift arm assembly  60  preferably is movable around the turret shaft  36  in conjunction with the turret bearing ring  50 , i.e. when the turret bearing ring  50  rotates around the turret shaft  36 , the lift arm assembly  60  moves circumferentially around the turret shaft  36 . 
     Referring to FIG. 3, the lift arm assembly  60  moves between a first position  62  and a second position  64  around the turret shaft  36 . In the preferred embodiment, the first and second positions are about 90 degrees apart circumferentially around the turret shaft  36 . The relative locations around the turret shaft  36  of the first and second positions, however, can be selected as desired, limited only by the width of the lift arm assembly  60 . 
     Alternatively, additional positions can be provided around the turret shaft  36 , as illustrated in FIG.  3 . For example, two additional positions for the lift arm assembly  60  can be provided. In the example of FIG. 3, two lift arm assemblies  60  can be moved between four positions around the turret shaft  36 . The four positions are each about 90 degrees from adjacent positions. Alternatively, four lift arm assemblies  60  can be provided on the machine  30 . 
     When additional lift arm assemblies  60  are provided, a subsequent roll  31 ′ (or rolls) can be loaded onto the machine and held at a waiting position until the previous roll  31  is fully unwound; The subsequent roll  31 ′ is then moved into the unwinding position  64  after the previously unwound roll  31  has been moved out of the unwinding position  64 . 
     In the preferred embodiment as exemplified in FIG. 3, the loading and unwinding operations take place at the first and second positions,  62  and  64 , respectively. The first and second positions, however, are interchangeable with respect to the operation performed at each position. The terms “first” and “second” are used for descriptive purposes herein in reference to the relative positions of the lift arm assembly  60  as it moves around the turret shaft  36 . 
     Referring to FIGS. 1-5, the lift arm assembly  60  includes two generally parallel lift arms  70  which accept and support the roll  31  of material during loading and unwinding operations, respectively. Each lift arm  70  has a first end  72  for supporting the roll  31  and a second end  73  operably associated with a lift arm track  80 . The lift arms  70  are horizontally movable relative to each other along the lift arm track  80 , as described in further detail below. 
     Referring again to FIG. 3, the first end  72  of each lift arm  70  includes a pilot bearing  74 . Each pilot bearing  74  is preferably cylindrical with a tapered leading end  75  and is freely rotatable around a pilot bearing axle  76 . Each pilot bearing axle  76  is substantially perpendicular to its respective lift arm  70 . Rotary bearings or any other mechanism known in the art can be used to provide relatively frictionless and free rotation of the pilot bearings  74 . 
     The pilot bearings  74  are located on each lift arm  70  directly across from each other so as to be substantially coaxial. The pilot bearings  74  are adapted to fit into the hollow core  33  of the roll  31  thereby supporting the roll  31  at both ends of the hollow core  33  without the use of a shaft. 
     The second end  73  of each lift arm  70  is slidably mounted onto the lift arm track  80 , as shown in FIGS. 4 and 5. Preferably, the lift arm track  80  is an elongated beam that is disposed generally horizontally with respect to the turret shaft  36 . In the embodiment illustrated in FIG. 4, the lift arm track  80  includes two protruding mounting ears  81  for connecting to the protrusion  52  on the turret bearing ring  50 . 
     A lift arm linear bearing  82  is disposed at the second end  73  of each lift arm  70 . The lift arm linear bearing  82  is engaged with and slides along the lift arm track  80  to provide the horizontal movement of the lift arms  70 . Each lift arm linear bearing  82  is attached to a rack gear  84  that extends toward the opposite lift arm  70 . The rack gears  84  are generally perpendicular to the lift arms  70  and parallel to the lift arm track  80  and each other. 
     A pinion gear linear bearing  86  is mounted to the lift arm track  80 , preferably between the lift arm linear bearings  82 . A pinion gear  88  is rotatably mounted to the pinion gear linear bearing  86 . The rack gears  84  are spaced apart from each other, and the pinion gear  88  is located between the rack gears  84  and engaged with both rack gears  84  simultaneously. 
     The motion of the lift arms  70  toward and away from one another is controlled by a roll clamp actuator  90  which is mounted to the pinion gear linear bearing  86  and one of the lift arm linear bearings  82 . The roll clamp actuator  90  of the preferred embodiment is an extendable and retractable piston. Alternatively, the roll clamp actuator  90  can comprise any mechanism that is capable of transmitting linear force. 
     The roll clamp actuator  90  moves the lift arm linear bearing  82  to which it is mounted and the pinion gear linear bearing  86  laterally relative to each other along the lift arm track  80 . As the lift arm linear bearing  86 , and thus the rack gear  84  to which it is attached, moves, the rack gear  84  rotates the pinion gear  86 , which in turn moves the other rack gear  84  in the opposite direction. The rack and pinion system provides for equidistant horizontal movement of the lift arms  70 . 
     A web tracking actuator  92  is provided which is also preferably embodied in an extendable and retractable piston. As shown in FIG. 5, one end of the web tracking actuator  92  is attached to the end of the lift arm track  80 , and the other end of the web tracking actuator  92  is attached to the pinion gear linear bearing  86 . Motion of the web tracking actuator moves both lift arms  70  simultaneously in either direction along the lift arm track  80 . This movement can be used to position the roll  31  of material  32  to the proper location with respect to the drive tower for unwinding. 
     In operation, the lift arms  70  are moved away from each other for roll loading and removal by extending the roll clamp actuator  90 . The lift arms  70  are moved toward each other to rotatably hold the roll  31  between the pilot bearings  76  by retracting the roll clamp actuator  90 . Preferably, and as illustrated in FIG. 3, the pilot bearings  76  are at least partially inserted into the roll core  33  when the lift arms  70  are moved toward each other. Thus, the lift arms  70  support the roll  31  during turning of the roll  31  to unwind the material. 
     Alternatively, the pilot bearings  76  can be pressed against the side of the roll  31  to hold and support the roll  31 . While the pilot bearings  76  are provided for supporting the roll  31  without a shaft or spindle, another alternate embodiment of the machine  30  includes lift arms  70  configured for use with a shaft or spindle inserted into the core  33 . The first ends  72  of the lift arms  70  can alternatively be adapted to accept the shaft and support the roll  31  by the shaft during unwinding. 
     Referring again to FIG. 3, once the roll  31  is clamped between the pilot bearings  76  at the loading position, the lift arm assembly  60  is moved in conjunction with its corresponding turret bearing ring  50  around the turret shaft  36  to the second or unwinding position  64 . Once a roll  31  is loaded and held by the lift arms  70 , the lift arm assembly  60  is supported by the guide cam  40  as shown in FIGS. 1 and 2. 
     As shown in FIG. 6, the guide cam  40  of the preferred embodiment is a generally flat, horizontally disposed disk and is located around the turret shaft  36  below the turret bearing rings  50 . The guide cam  40  includes an outer rim  44  around its periphery for supporting the lift arm assembly  60  while the lift arm assembly  60  moves around the turret shaft  36  between the first and second positions,  62  and  64 . The outer rim  44  of the guide cam  40  is continuous except for a generally rectangular cutout  46  defined by the outer rim  44  corresponding to the first or loading position  62  in the preferred embodiment. 
     Referring again to FIGS. 1-3, the lift arm assembly  60  is supported at the outer rim  44  of the guide cam  40 . Preferably, a support beam  66  extends from the lift arm track  80  toward the outer rim  44  of the guide cam  40 . The support beam  66  has a distal end  67  that is operably associated with the outer rim  44  and a proximal end  68  that is connected to the lift arm assembly  60 , preferably at the lift arm track  80 . 
     A cam yoke roller  100  is mounted to the distal end  67  of the support beam  66 . The cam yoke roller  100  cooperates with the outer rim  44  to support the lift arm assembly  60  during its movement around the turret shaft  36 . 
     The cam yoke roller  100  comprises a block  102  defining a groove  104  therein. The cam yoke roller  100  is slidably mounted on the outer rim  44  of the guide cam  40  with the outer rim  44  positioned within the groove  104  when the lift arm assembly  60  is in the up position  63 , as illustrated in FIGS. 1 and 2. In this manner, the cam yoke roller  100  slides along the circumference of the outer rim  44  of the guide cam  100 . Alternatively, the cam yoke roller  100  can include any suitable type of bearing configuration for providing rolling contact between the cam yoke roller  100  and the guide cam  40 . The term “slidably” is to be understood to include rolling contact. 
     Referring to FIGS. 1,  7 , and  8 , a lifting mechanism  110  is associated with the cam yoke roller  100  for pivoting the lift arm assembly  60  by moving the cam yoke roller  100  along an arc, the center point of which corresponds to the mounting point  54  of the lift arm assembly  60  on protrusion  52  of the turret bearing ring  50  and the radius of which is the distance between the mounting point  54  and the cam yoke roller  100 . FIGS. 1 and 7 show the lifting mechanism  110  with the lift arm assembly  60  in the down position  65 , and FIG. 8 shows the lifting mechanism  110  with the lift arm assembly  60  in the up position  63 . 
     In the preferred embodiment as exemplified in FIGS. 6-8, the lifting mechanism  110  includes a lift truck  112  that engages the cam yoke roller  100  to move the lift arm assembly  60  between the up and down positions. The lift truck includes a front end  114 , a back end  115 , two side surfaces  116 , and guide pins  118  protruding from the side surfaces  116 . 
     The lift truck  112  is operably associated with a guide track  120  (shown in FIG. 6) which defines a curved groove  122  that corresponds to the arc having its center point at the mounting point  54  and its radius from mounting point  54  to cam yoke roller  100 . The guide pins  118  protrude into the groove  122  and thereby guide the lift truck  112  as it moves the lift arm assembly  60  between the up and down positions. 
     A lifting cylinder  124  connected to the back end  115  of the lift truck  112  provides the force to move the lift truck  112  between an engaged position  125  (shown in FIG. 8) and a disengaged position  126  (shown in FIG.  7 ). The engaged position  125  corresponds to the up position  63  of the lift arm assembly  60 , and the disengaged position  126  corresponds to the down position  65 . The lifting cylinder  124  is preferably hydraulic or pneumatic, but can be any type of force transmitting device known in the art. 
     The lift truck  112  further includes a cam section  128  extending from the front end  114 . The cam section  128  is configured to engage the guide cam  40  by fitting within the cutout  46  when the lift truck  112  is in the engaged position  125 . The cam section  128  has an outer edge  130  that has a curvature matching that of the curvature of the outer rim  44  of the guide cam  40 . Thus, the curvature of the outer rim  44  is continued along the outer edge  130  of the cam section  128  when the lift truck is in the engaged position  125 . 
     In operation, when the lift arm assembly  60  moves to one of the first and second positions, which corresponds to the loading position, the lift truck  112  is in the engaged position  125  with the cam section  128  interposed in the cutout  46 . Once the lift arm assembly  60  is moved into the loading (or first) position  62 , the cam section  128  is positioned within the groove  104  of the cam yoke roller  100 . The lifting cylinder  124  then retracts to pull the lift truck  112  from the engaged position  126  to the disengaged position  125 . Thus, the cam yoke roller  100  moves together with the lift truck  112  to pivot the lift arm assembly  60  to the down position  65 . 
     At this point or prior thereto, the lift arms  70  are moved apart as described above to allow a roll  31  to be placed between the lift arms  70  with the core  33  of the roll  31  aligned with the pilot bearings  74 . Once the roll  31  is positioned between the pilot bearings  74 , the lift arms  70  are moved toward each other until the pilot bearings  74  are engaged in the core  33  on each side of the roll  31 . 
     The lift truck  112  is then moved back to the engaged position  125  (FIG.  8 ), thereby lifting the lift arm assembly  60  with the roll  31 . Once the lift truck  112  is returned to the engaged position  125  and the cam section  128  is interposed in the cutout  46  (and thus horizontally aligned with the guide cam), the lift arm assembly  60  is moved to the second (or unwinding) position  64 . The roll  31  is then in position to be unwound. 
     Referring again to FIGS. 1 and 2, the unwinding operation is accomplished in the preferred embodiment described herein by a drive tower  140  which extends upwardly from the turret shaft  36 . 
     The drive tower  140  includes an upwardly extending tower frame  142 . The tower frame  142  has generally vertical first and second side walls,  144  and  145 . The first and second side walls,  144  and  145 , are preferably elongated, generally rectangular members that provide sufficient structural support for the drive tower  140 . 
     The tower frame  142  further includes an upper portion  146  and a lower portion  147 . The lower portion  147  includes a bracket  148  that extends between the first and second side walls,  144  and  145 . The bracket  148  provides the mount for the tower frame  140  to the turret shaft  36 . 
     A belt frame axle  149  extends through the first and second side walls,  144  and  145 , of the tower frame  142  adjacent to the upper portion  144 . In the preferred embodiment, the belt frame axle  149  can extend only partially through the side walls of the tower frame  142 . 
     The drive tower  140  further includes a belt frame  150  between the first and second side walls,  144  and  145 . The belt frame  150  includes a first member  154 , a second member  155 , an axle end  156 , and a free end  157 . The first and second members,  154  and  155 , are located adjacent to and between the first and second sides,  144  and  145 , respectively, of the tower frame  142 . The axle end  156  is pivotally attached to the belt frame axle  149 . The free end  157  is adjacent the lower portion  147  of the tower frame  142  when the drive tower  140  is not unwinding a roll  31 . The free end  157  of the belt frame  150  is free to swing away from the tower frame  142  because the belt frame  150  pivots around the belt frame axle  149  at the upper portion  146  of the tower frame  142 . 
     In the preferred embodiment as illustrated in FIG. 2, a belt frame cylinder  152  is provided on the drive tower  140  to pivot the free end  157  of the belt frame  150  outwardly toward the roll  31  during the unwinding operation. Alternatively, any known mechanism for pivoting the belt frame  150  can be used. 
     An upper roller  160  and a lower roller  161  are both disposed between the first and second members,  154  and  155 , of the belt frame  150 . The upper roller  160  is coaxial with the belt frame axle  149 , and the lower roller  161  is adjacent to the free end  157  of the belt frame  150 . 
     A turning belt  164  extends around the upper and lower rollers,  160  and  161 , and has a contact surface  166  for frictionally contacting the roll  31  and driving the roll  31 . During the unwinding operation, the belt frame  150  is pivoted at the belt frame axle  149  such that the free end  157  of the belt frame  150  extends outwardly from the tower frame  142  and toward the roll  31  being held by the lift arm assembly  60  in the up position  63 . 
     A turning belt drive  170  provides the rotation of the turning belt  164 . The turning belt drive  170  preferably is a motor mounted to the upper portion  146  of the tower frame  142  and is connected to the belt frame axle  149  by a drive belt  172 . The turning belt drive motor turns the belt frame axle  149 , which in turn turns the upper roller  160 , thus rotating the turning belt  164 . When the contact surface  166  of the rotating turning belt  164  contacts the roll  31 , the roll  31  is rotated, thereby unwinding the material therefrom. Alternatively, the belt drive can be operably associated with either the upper roller  160  or the lower roller  161 . 
     A roll indicator  180  can be provided to indicate an amount of material on a roll  31  being unwound, i.e., to signal that a roll  31  has been unwound or is nearly fully unwound. The roil indicator  180 , if provided, is preferably a lamp mounted to the upper portion of the tower frame  142  and is operably associated with a sensor that monitors the amount of material on the roll. Alternatively, the roll indicator  180  can be remotely located and can be an audible signal, or any type of signaling system known in the art. 
     The foregoing description and the accompanying drawings are illustrative of the present invention. Still other variations and arrangements of parts are possible without departing from the spirit and scope of this invention.