Abstract:
This core plugging station relates generally to preparing rolls of previously wound material for an unwinding machine. The core plugging station improves the automation of moving rolls of sheet form material and the like to be loaded in preparation for unwinding. When a previously loaded roll has been unwound a spent core station disposes of the remaining core. The process sequentially moves rolls of material having cores from a core plugging station to an unwinding station and sequentially moves spent rolls of material from the unwinding station back to a spent core station.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of provisional application Ser. No. 61/067,592, filed Feb. 29, 2008. 
    
    
     TECHNICAL FIELD 
     The present invention relates generally to an apparatus and method for preparing rolls of previously wound material for an unwinding machine. More particularly, the method improves the automation of moving rolls of sheet form material and the like to be loaded in preparation for unwinding and then, when a previously loaded roll has been unwound disposing of the remaining core. 
     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, tissue and paper. 
     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 unwound for further processing such as cutting, folding or printing. The rolls of raw material may have a length of up to about 300 inches (750 cm) and a weight of up to about 8,000 lbs (3600 kg). Machines such as printing machines or laminating machines to which the sheet is supplied by the unwinding machine usually require the sheet to be supplied at a constant speed and tension. When nearly the entire roll has been unwound from the core, it is necessary for the machine to stop unwinding sheet from the almost empty roll and to commence unwinding sheet from a new roll without any interruption in the supply of sheets to the operating machine. It is thus necessary for the sheet to be cut from the nearly empty roll and to be secured to the sheet on the new roll to ensure continuous supply of sheet. 
     Conventionally, the rolls of stock material are prepared for the winding and unwinding machine in a rather labor intensive operation that can sometimes present dangerous working conditions for the operator. The large rolls of material are usually delivered to a work station by conveyor or cart or the like. At the work station, the operator inserts plugs into each end of the roll of stock material. The operator then commonly uses an overhead crane to engage the plugs and lift the roll of stock material off the conveyor or cart. The operator then prepares the roll for delivery to the unwinding machine. Such preparation usually involves cleaning the surface of the roll and positioning the leading edge of the web of stock material in a certain orientation. Using the overhead crane, the operator then lifts the prepared roll of material and delivers it to the unwinding station. The operator then uses the overhead crane to pick up a spent roll of material and return the spent roll to the work station wherein the operator removes whatever stock material remains on the core, removes the plugs, and delivers the spent core to a spent core storage area. It can be seen that having the operator in such close proximity with the large roll of stock material that sometimes can reach upwards of 8000 pounds presents many challenges for work place safety and efficiency. 
     Clearly, a need exists for a unique method to quickly change to a new roll once the previous roll is spent. 
     BRIEF DESCRIPTION OF THE INVENTION 
     We have developed a unique method to efficiently and safely prepare and transport a new roll of raw material to the apparatus and unwinding station, while also retrieving a spent roll. 
     The automated process sequentially moves rolls of material having cores from storage to a core plugging station and then to an unwinding station and sequentially moves spent rolls of material from the unwinding station back to a spent core station. The process comprises the steps of sequentially: 
     (a) feeding unplugged rolls of material having cores to a core plugging station; 
     (b) automatically aligning at least one core plug with the core of the roll of material in the core plugging station; 
     (c) automatically inserting the at least one core plug into the core of the roll of material; 
     (d) feeding the plugged roll of material to an unwinding station; 
     (e) removing a spent roll of material from the unwinding station; 
     (f) automatically removing the at least one core plug from the spent roll; and, 
     (g) feeding the spent roll of material to a spent core station. 
     In a preferred embodiment, the plugging station provides for automatically elevating the roll to allow it to be prepared before sending it to the unwinding station. 
     In another preferred embodiment, the step of automatically aligning further includes vertically aligning and horizontally aligning the core plug with the core of the roll of material. In another embodiment, the core plug has a central axis, the core of the roll of material has a central axis and the step of automatically aligning further includes aligning the central axis of the core plug with the central axis of the core of the roll of material. The process further includes the step of a spent core gripper receiving the spent roll and transporting it to the spent core station. 
     Other objects and advantages of the present invention will become apparent to those skilled in the art upon a review of the following detailed description of the preferred embodiments and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top view of the apparatus of the present invention adjacent an unwinding machine. 
         FIG. 2  is an enlarged, top view showing the apparatus of the present invention in greater detail. 
         FIG. 3  is a perspective view showing a roll cart conveyor with a turntable assembly. 
         FIG. 4  is a top view of the roll cart with conveyor removed to show the turntable in greater detail. 
         FIGS. 5A and 5B  are perspective views showing the turntable of the roll cart in greater detail. 
         FIG. 6  is a perspective view showing a core plugging station. 
         FIG. 6A  is a detail view of a core plug positioned on a core plug probe. 
         FIG. 7  is a perspective view of a spent core cart with a core gripper assembly. 
         FIG. 8  is a perspective view of the undercarriage of the spent core cart. 
         FIG. 9  is a perspective view showing the core gripper assembly. 
         FIG. 10  is a side view of the core gripper showing the closed position in phantom. 
         FIG. 11  is a top view of a spent core conveyor. 
         FIG. 12  is a side view of the spent core conveyor showing minimum size spent core and a maximum size spent core in phantom. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The apparatus of this invention sequentially receives rolls of raw material wound about hollow cores and automatically moves the rolls to a core plugging station. The rolls are plugged and prepared for use. The rolls are then moved to an unwinding machine. The apparatus and method of the invention then automatically and sequentially moves spent rolls of material from the unwinding machine back to a spent core station. The apparatus comprises: 
     (a) a core plugging station; 
     (b) a roll conveyor station for feeding unplugged rolls of raw material having hollow cores to the core plugging station; 
     (c) a means for automatically aligning at least one core plug with the core of a roll of material in the core plugging station; 
     (d) a means for automatically inserting the at least one core plug into the core of the roll of material; 
     (e) a means for transferring the plugged roll of material to an unwinding station; 
     (f) a means for removing a spent roll of material from the unwinding station; 
     (g) a spent core station; 
     (h) a means for removing the at least one core plug from the spent roll; and 
     (i) a means for feeding the spent roll of material to the spent core station. 
     The roll of raw material is transferred from an inventory stock of rolls via conveyor until it is positioned on the roll cart conveyor. The roll cart conveyor is positioned on rails that extend between the conveyor station and the core plugging station. The roll cart conveyor automatically transports the roll of raw material to the core plugging station. The roll cart conveyor further includes a turntable assembly for angularly positioning the roll of raw material within the core plugging station. 
     In the preferred embodiment, the core plugging station includes the means for automatically aligning the at least one core plug, the means for automatically inserting the at least one core plug, and the means for removing the at least one core plug. The means for automatically aligning the at least one core plug further includes a lifting frame designed to vertically align the central axis of the core plug with the central axis of the hollow core and a roll cart conveyor for horizontally aligning the central axis of the core plug with the central area of the hollow core. Once the central axes are aligned, both vertically and horizontally, the core can be rotated by a turntable assembly to angular align the center lines. Upon complete vertical, horizontal and angular alignment, the core plugs are inserted into the hollow core at each end of the roll of raw material. In the preferred embodiment, there are two core plugs, one on each end. The core plugs are retained in the core plugging station by friction fit. 
     Once the core plugs are inserted into the hollow core of the roll of raw material, the lifting frame lifts the roll of raw material vertically so that it no longer engages with the roll cart conveyor. The lifting frame then supports the roll of raw material while the roll is prepared by a worker for placement in the unwinding machine. Once the roll is prepared an overhead crane lowers carry hooks to engage the core plugs, the core plug probes are withdrawn from the core plugs and the overhead crane lifts and carries the roll of raw material into position on the unwinding machine. 
     In the preferred embodiment, the roll of raw material replaces a spent roll of raw material. On the return trip, the overhead crane retrieves the spent roll of raw material and transfers the spent roll to the spent core cart. The spent core cart will transfer on tracks between the spent core station and the plugging station. At the plugging station, the core plug probes are inserted into the core plugs and the core plugs are removed from the spent core. The spent core cart returns to the spent core station where the worker cleans and prepares the core for reuse. Once the core is prepared and cleaned for reuse, a conveyor transports the spent core to a spent core storage bin. 
     Referring now to  FIGS. 1 and 2  the apparatus for loading and unloading an unwinding machine is shown in greater detail. The apparatus includes a core plugging station  10 , a spent core station  20  adjacent an unwinding machine  30 , and a roll conveyor station  40 . The roll conveyor station  40  includes a plurality of feed belt conveyors  42 ′,  42 ″ and a roll cart conveyor  44 . Rolls of raw material (not shown) are positioned on conveyor  42 ′ and fed by conveyor  42 ″ to roll cart conveyor  44 . If for some reason the roll of raw material is not properly oriented or is sequentially out of step with the required automated process of the unwinding machine, a parking station conveyor  42 ′″ is available. Such out of sequence roll can be moved from the roll cart conveyor  44  to the parking station  42 ′″ and held until it is sequentially matched to move to the unwind machine. At which time conveyor  42 ′″ moves the parked roll of raw material back to the roll cart conveyor  44 . 
     The roll cart conveyor  44  is positioned on parallel tracks  45  for movement between the conveyor station  40  and the core plugging station  10 . In operation, once the roll cart conveyor  44  receives a roll of raw material, it automatically drives itself to a position in the core plugging station  10  proximate the core plugging machines  12 ,  12 ′. As will be discussed in detail later, the roll cart conveyor  44  positions the roll of raw material at a proper angular relationship with respect to the core plugging machines  12 ,  12 ′. The core plugging machines and roll cart conveyor  44  then move vertically and horizontally to visually align the center line of the core of the roll of raw material with the center line of the core plugs  111 ,  111 ′. Once the roll of raw material receives the core plugs  111 ,  111 ′ the core plugging machines  12 ,  12 ′ elevate the roll of raw material off of the roll cart conveyor  44 . The roll cart conveyor  44  then travels back to the conveyor station  40  to receive another roll of raw material. 
     Once the roll of raw material at the plugging station  10  is prepared for transport to the unwind machine, the overhead crane  50  ( FIG. 1 ) travels to the plugging station  10  and retrieves the roll of raw material for transport to the unwind machine. 
     Upon return from the unwind machine, the overhead crane  50  will retrieve a spent roll of material and return the spent roll of material to the spent core station  20 . As will be discussed in detail with respect to further figures, the spent core station  20  has a spent core cart  122  with a gripper assembly. 
     The spent core cart  122  travels on rails between the spent core station  20  and the plugging station  10 , where the core plugs are removed from the spent core. The spent core cart  22  then returns to the spent core station  20  where the worker cleans remaining raw material from the core. Once the core is cleaned, the spent core conveyor  24 ,  26  transfers the spent core to the spent core lift  28  for depositing in spent core storage (not shown). 
     Referring now to the remaining figures, the various components of the conveyor station  40 , plugging station  10 , and spent core station  20  will be discussed in greater detail. Referring now to  FIGS. 3 ,  4  and  5 , the roll cart conveyor  44  is shown in greater detail. The roll cart conveyor  44  includes a roll cart  46  which is positioned on tracks  45  ( FIG. 4 ). Referring now to  FIG. 4 , servo motor  58  is linked to drive wheels  59  by axle  60  for driving the roll cart  46  along the tracks  45 . Mounted on the roll cart  46  is turntable  52  and the roll cart conveyor  48  is engaged with the turntable  52 . Referring now to  FIGS. 5 and 5A , the turntable  52  is shown in greater detail. The turntable  52  includes brackets  51  for engaging with the roller conveyor  48  and circular drive bracket  53  for engaging with the roll cart  46 . Servo drive motor  56  is engaged with the circular drive bracket  53  by drive belt  55 . As the servo motor  56  drives the drive belt  55  it causes the turntable  52  to rotate about the circular drive bracket  53 . Preferably, a laser aligning device (not shown) feeds signals to the servo motor  56  to assist in properly aligning the roll of raw material within the plugging station. Conveyor drive  54  is used to drive conveyor belt  48 . 
     Referring now to  FIG. 6 , the plugging station will be described in further detail. Each core plugging machine includes a base frame  101  and a lifting frame  103  positioned within the base frame  101  and a pulling frame  102  positioned on the lifting frame  103 . The lifting frame  103  moves vertically within the base frame  101 . Drive motor  107  is positioned on top of the base frame  101  and is engaged with the lifting frame  103  by means of drive chains  117  engaged with drive pulleys  116  which in turn are engaged with lifting chains  115 . The pulling frame  102  includes a drive motor  108 , a pair of guide rails  113  and a pulling head  106  positioned for movement on the guide rails  113 . The drive motor  108  is engaged with the pulling head  106  by drive belt  112 . The pulling head  106  carries the core plug probe  105  and core plug clamp  109 . Referring now to  FIG. 6A , the core plug probe  105  carries the core plug  111  and the core plug clamp  109  engages a lip  113  of the core plug  111  to hold the core plug  111  on the core plug probe  105 . After the core plug  111  is inserted into the roll of raw material, the core plug clamp  109  disengages from the lip  113  of the core plug  111  and the pulling head  106  retracts thus disengaging the core plug  111  from the core plug probe  105 . Sensors (not shown), preferably lasers, are located on the pulling head  106  to assist in aligning the center line of the core plug probe  105  and core plug  111  with the center line of the roll of raw material. 
     In operation, the roll cart conveyor  44  positions the roll of raw material proximate the core plugging station  10  and the sensors on the pulling head  106  align the center line of the core plug probe  105  and core plug  111  with the center line of the core of the roll of raw material. Alignment is effected by vertical movement of the lifting frame  103  and horizontal movement of the roll cart conveyor  44  on the rails. Angular alignment is achieved by the turntable  52  on the roll cart conveyor  44 . Once the proper alignment of the center lines of the core of the roll of raw material and the core plug  111  are aligned, drive motor  108  is activated to move the pulling head forward toward the roll of raw material thus engaging the core plug  111  within the core. Drive motor  107  is then activated to elevate the lifting frame  103 , thus lifting the roll of raw material off the surface of the roll cart conveyor  44 . The roll of raw material is then prepared for transfer to the unwind machine by the worker. After the roll of raw material is prepared, the overhead crane  50  arrives to engage the core plugs  111   111 ′. Clamping member  109  disengages from the lip  113  of the core plugs  111   111 ″ and the roll of raw material can then be transported to the unwind machine. 
     Referring now to  FIGS. 7-10 , the spent core cart  22  having a core gripper assembly  123  will be described in detail. The spent core cart  22  consists of three main components: the core gripper assembly  123 , conveyor  122  and cart frame  125 . Referring to  FIG. 8 , the cart frame  122  includes wheels (not shown) for engagement with the rails  45  such that the spent core cart  22  can move between the spent core station  20  and the plugging station  10 . Drive motor  127  is engaged with the wheels by means of drive shaft  128 . 
     Referring now to  FIGS. 9 and 10 , the spent core gripper  123  is mounted on the frame  125  by base frame  130 . Gripper arms  131  are mounted for rotation on the base frame  130  in bearings  135 . The gripper arms  131  are movable into position to engage with a spent core of any given diameter through the adjustable linkage comprising pivot arms  139  engaged with a pair of pneumatic cylinders  136  through clevis  132  and adjustment rod  134 .  FIG. 10  shows a side view of the core gripper  123  with the gripper arms  131  in an open disengaged position and, in ghost, the gripper arms in a closed engaged position  131 ′ with a spent core. 
     Referring now to  FIGS. 11 and 12 , the spent core conveyor  22  includes a frame  140 , drive rollers  141 , motor  143  and belting  144 . If desired, conventional non-drive rollers (not shown) may be located beneath the belting  144  to support the belt under the weight of the spent core.  FIG. 12  is a side view of the spent core conveyor  122  showing a minimum circumference spent core  147  and a maximum circumference spent core  148  in phantom. When a 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. The time spent loading, unloading and reloading the machine results in decreased production of the final product. As can be seen in phantom, spent cores  147  and  148 , the size of the spent core varies widely. The apparatus of the spent core conveyor  122  and the spent core gripper have been designed to handle these wide variations. 
     The above detailed description of the present invention is given for explanatory purposes. It will be apparent to those skilled in the art that numerous changes and modifications can be made without departing from the scope of the invention. Accordingly, the whole of the foregoing description is to be construed in an illustrative and not a limitative sense, the scope of the invention being defined solely by the appended claims.