Patent Publication Number: US-2022212893-A1

Title: Robotic core plug inserter

Description:
FIELD OF THE INVENTION 
     The present invention generally relates to a manufacturing method and apparatus. More specifically, the present invention relates to a new and useful method and apparatus for inserting core plugs into wound paper cores that support rolls of paper, plastic film and other materials during manufacture. 
     BACKGROUND OF THE INVENTION 
     The present invention consists of a new method and apparatus designed to replace the manual procedure of inserting fabricated, molded or wooden core plugs into large cores upon which have been wound continuous ribbons or sheets of paper, plastic film or other materials for subsequent material handling and/or storage purposes. 
     Prior art has consisted of accumulating core plugs produced of and by various materials and manufacturing methods, manually positioning them at the entry of spiral wound paper cores, subsequently impacting the core plugs about their periphery with a plastic covered, flat faced hammer until their 1¼″ to 1½″ thick by 12″ diameters are driven into the internal diameters of cores at least 1¾″. This manual insertion method randomly causes damage to core plugs and cores, sometimes causing the loss of entire rolls. In addition, the process creates a physical hazard for installers, putting their fingers and hands in awkward positions to first position the core plug inside the core, then having to strike the core plug on an angle in order to initiate its entry into the core. 
     It is an object of the present invention to provide for a core plug delivery system that will permit automatic stacking and retrieval of core plugs from a vertical magazine by a robotically positioned inserter. 
     It is a further object of the present invention to provide a robotically positioned inserter capable of initially confirming a core plug&#39;s location through a machine vision camera, then physically gripping the core plug by its center hole for transfer to a horizontally positioned core with paper, plastic film or other materials already wound upon it. 
     It is yet another object of the present invention to provide a robotically positioned inserter that is capable of presenting the captured core plug to the opening of a horizontal core in an oblique fashion, then maneuvering it through an oblique to inline core plug-to-core orientation sequence until, with appropriate installation forces, to push the core plug into the core until it is fully seated. 
     Another object of the present invention is to generate a robotic software program (capable of not only implementing standard XYZ position commands for the inserter&#39;s pick and place movements, but also utilizing the inputs of a machine vision camera with appropriate spatial position and solenoid air valve commands to position the inserter to pick up core plugs from a core plug magazine, find the center of cores in horizontally staged rolls of paper or plastic film, and implementing a series of core plug-to-core centerline insertion angles for inserting core plugs into the horizontal cores until the core plugs are successfully installed into cores at an appropriate depth without physical damage to the core or core plugs. 
     These and other objectives of the invention are achieved by the method and apparatus described below with reference to the accompanying drawings. 
     SUMMARY OF THE INVENTION 
     In keeping with the present invention, continuous ribbons or sheets of paper and plastic film are wound onto large, spiral wound paper cores for material handling purposes and support while in storage. Due to the manner in which the rolls are clamped by large hydraulically actuated, semi-circular clamps during their movement from the initial winding of the paper sheet or plastic film and their final unwinding of full width or slit sheets of material, cores can become collapsed preventing the subsequent mounting of rolls on standard unwind stands. 
     Since the winding and/or unwinding of product require the cores to be round in order to fit onto supporting arbors or thru shafts, the cores have to be forcefully opened up and made round by hydraulic mandrels that diametrically expand the internal diameters of cores. Since these attempts to correct the crushing and breakage of paper fibers that makeup the spiral wound cores typically fail, significant losses of the product wound and the labor expended to retrieve it occur. 
     To address the above issues the present invention provides a fully automated method to reinforce cores during the intermediate handling and/or storage of rolls during manufacturing. The invention consists of a core plug magazine, core plug inserter incorporating an air cylinder, machine vision camera, six-axis robot and a roll transfer conveyor. 
     The process begins with a quantity of 12″ diameter by 1¼″ to 1½″ thick core plugs being loaded into the vertical accumulator of the core plug magazine. The magazine is equipped with a series of sensors that detect whenever a core plug, resting in the delivery position of the magazine, is picked and subsequently removed by the core plug inserter. Upon detection that a core plug has been removed by the core plug inserter, the core plug magazine automatically transfers another core plug from the vertical accumulator into the delivery position. This sequence continues automatically until a separate sensor detects that there are no further core plugs in the accumulator at which time an operator is alerted to reload the accumulator with additional core plugs. 
     The robotic core plug inserter, secured to the extended arm of a six-axis robot, is staged immediately above the core plug magazine at the beginning of a core plug transfer and insertion cycle. The inserter, equipped with an air cylinder driven gripper finger and plug capture flange, is oriented in such a fashion so as to permit the gripper finger to pass through the center hole of a magazine fed core plug. If for some reason the alignment requires adjustment, the camera, mounted on the side of the inserter, captures the offset position and, through the robot&#39;s programmable logic controller and custom software program, realigns the inserter with the hole for gripper finger clearance upon insertion. 
     Upon confirmation that a new roll is at the first core plug insertion position on the roll transfer conveyor, the inserter&#39;s camera captures and compares the inserter&#39;s position relative to the core plug. The inserter, before beginning insertion of the gripper finger, realigns itself for clearance with the core plug hole, if required. The inserter then begins extending the gripper finger in and through the core plug hole until the plug capture flange contacts the upper surface of the core plug. At that point an external laser sensor confirms contact has been made and sends a signal to the robot&#39;s programmable logic controller to stop forward movement of the robot. The inserter is then commanded to move laterally until the gripper shaft, upon which the gripper finger is secured, is centered on the core plug hole. 
     The air cylinder, attached to the gripper finger by way of the gripper shaft, is then commanded to retract the gripper finger through actuation of a solenoid operated valve on the side of the inserter. The gripper finger, forcefully coming into contact with the underside of the core plug by virtue of pneumatic pressure, captures the core plug between its finger and plug capture flange. 
     With confirmation that the core plug is captured by means of a magnetic piston sensor on the side of the air cylinder, the robotic plug inserter is retracted from the core plug magazine and proceeds toward the open end of the new roll. Upon arriving at the roll, the robot is commanded to make a vertical pass with the inserter&#39;s camera across the entire face and along the vertical centerline of the roll in order to identify the exact center of the 12″ diameter core. With information defining the precise location of the height, lateral offset and depth of the core&#39;s open face, the robot is robotically directed, through a programable logic controller and custom software program, to orient the core plug&#39;s vertical centerline at an angle that is 30 to 45 degrees above the core&#39;s horizontal centerline while simultaneously positioning the core plug&#39;s center coincident with the core&#39;s horizontal centerline. 
     Upon confirmation that this position has been assumed, the core plug is then moved horizontally forward until the core plug&#39;s center is at a predetermined depth for its placement within the core&#39;s inside diameter. 
     With validation by the robot&#39;s programmable controller that the core plug is at the selected position for its placement within the core, the robot begins to rotate the core plug inserter and captured core plug about its center until the 30 to 45 degree angular displacement between the core plug&#39;s vertical centerline is coincident with the core&#39;s horizontal centerline. At that point the core plug&#39;s outside diameter is fully supporting the spiral wound paper core&#39;s internal diameter with the flat external front and rear faces of the core plug at right angles to the core&#39;s horizontal centerline. 
     Upon confirmation that the core plug has been correctly installed, the inserter&#39;s gripper finger is extended by actuation of the solenoid valve, and subsequent extension of the air cylinder occurs. The robot is then commanded to move the inserter laterally to provide a clear path for removal of the gripper finger from the core plug&#39;s center hole. 
     With confirmation that the air cylinder is fully extended through a sensor detecting the position of the magnetic piston and the lateral offset position has been achieved, the inserter&#39;s gripper finger is withdrawn from the core plug and the inserter is returned to its staged position above the core plug magazine in preparation for the next core plug insertion cycle. 
     With verification that the robot has staged the inserter above the magazine, and all other related systems are in their appropriate operational positions, the roll transfer conveyor moves the existing roll into a second position for insertion of a second core plug into the opposite end of the spiral wound core with the same sequence as described above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the robotic core plug inserter, supporting robot, core plug magazine and roll transfer conveyor. 
         FIG. 2  is a top view of the robotic core plug inserter, supporting robot, core plug magazine and roll transfer conveyor. 
         FIG. 3  is a rear view of the robotic core plug inserter, supporting robot, core plug magazine and roll transfer conveyor. 
         FIG. 4  is a side view of the robotic core plug inserter and supporting robot. 
         FIG. 5  is a perspective view of the robotic core plug inserter before it engages a roll on the transfer conveyor. 
         FIG. 6  is a perspective view of the robotic core plug inserter as it engages a roll on the transfer conveyor, before it seats the core plug insert. 
         FIG. 7  is a perspective view of the robotic core plug inserter seating the core plug insert in a roll. 
         FIG. 8  is front view of the robotic core plug inserter with captured core plug in its vertically aligned position. 
         FIG. 9  is a rear view of the robotic core plug inserter with captured core plug in its vertically aligned position. 
         FIG. 10  is a side view of the robotic core plug inserter with captured core plug in its vertically aligned position. 
         FIG. 11  is a side view of the robotic core plug inserter without a captured core plug. 
         FIG. 12  is a bottom view of the robotic core plug inserter without a captured core plug. 
         FIG. 13  is a cross-section view of the robotic core plug inserter fully extended. 
         FIG. 14  is a cross-section view of the robotic core plug inserter retracted. 
         FIG. 15  is a top view of the robotic core plug inserter. 
         FIG. 16  is an exploded view of the robotic core plug inserter. 
         FIG. 17  is a top view of the core plug magazine. 
         FIG. 18  is a perspective view of the core plug magazine. 
         FIG. 19  is a rear view of the core plug magazine. 
         FIG. 20  is a side view of the core plug magazine. 
         FIG. 21  is a cross-section view of the core plug magazine. 
     
    
    
     DETAILED DESCRIPTIONS OF THE INVENTION 
     All illustrations of the drawings are for the purpose of describing selected versions of the present invention and are not intended to limit the scope of the present invention. 
     Referring to  FIGS. 1-7 , there are shown two large rolls  20  of paper, plastic film or other material internally supported by spiral wound paper cores  2 . A second large roll is waiting and shown in dotted lines. These large rolls typically vary in size by 30 to 96 inches in diameter and 26 to 80 inches in width. The rolls are shown resting upon a roll transfer conveyor  8 , with the initial core plug insertion position shown by solid lines, and the second core plug insertion position shown by dashed lines. The core plug inserter  4  is shown attached to the end of a six-axis supporting robot  7  that is positioned adjacent the initial roll  20 . Core plugs  9  are shown resting upon a core plug magazine  3  and within the grasp of a core plug inserter  4 . 
     Referring now to  FIGS. 8-16 , the core plug inserter  4  is shown. The major components of the core plug inserter  4  consist of; an air cylinder  5 , machine vision camera  6 , gripper finger  10 , plug capture flange  11 , gripper shaft  13 , solenoid air valve  14  and magnetic piston sensors  15 . Air cylinder  5  and placement of the magnetic piston sensors  15  have been selected to accommodate the stroke required for core plugs  9  having nominal thicknesses between 1¼″ and 1½″. It should be understood that the air cylinder  5  and the placement of the magnetic piston sensors  15  can be adjusted to accommodate other desired thicknesses outside the stated range. Solenoid air valve  14 , operating in conjunction with a robot program, extends and retracts gripper shaft  13  to capture and release core plugs  9  secured between the gripper finger  10  and plug capture flange  11 . Additional components that make up the complete core plug inserter  4  include the robot mounting plate  16 , air cylinder gussets  17  and gripper shaft bushings  18 . Robot mounting plate  16  attaches the assembled core plug inserter  4  to a robot  7 . Air cylinder gussets  17  connect the robot mounting plate  16  to the core plug capture flange  11 . The core plug capture flange  11  also serves as a mounting surface for the air cylinder  5 . Gripper shaft bushings  18 , installed within core plug capture flange  11 , support gripper shaft  13  in its reciprocating movements. 
     Shown in  FIGS. 4-7  the core plug inserter  4  is shown in various positions from preparation for insertion of a core plug  9  into a core  2  ( FIGS. 4-5 ) to partial insertion ( FIG. 6 ) and finally fully inserted ( FIG. 7 ). In  FIGS. 5-6  the core plug inserter  4  is shown at an angle to large roll  20  and core  2 . In the preferred embodiment there is a 30 to 45 degree angular offset position of the core plug inserter  4  and captured core plug  9 , which permits the core plug to be inserted into the internal diameter of core  2 , with the least amount of force. However, the angular offset position can be adjusted to accommodate other cores or embodiments of the invention. The core plug inserter  4  rotates the core plug  9  30 to 45 degrees prior to inserting the core plug  9  into core  2 . Once the core plug  2  is inside the core  2 , the core plug inserter  4  rotates the core plug  9  so that it is perpendicular to the core  2 , at a predetermined depth. The core plug inserter  4  then extends the gripper finger  10  to release the core plug  9 . With core plug  9  released, the robot  7  can then extract the core plug inserter  4  from the core plug  9 , the core  2 , and roll  20 . 
     The position of core  2  varies based on the size of the roll. Further, if roll  2  is comprised of softer material, core  2  could be located in a different elevational position. Therefore there is a need to automatically position the core plug inserter  4  relevant to core  2 . The machine vision camera  6  is used to locate the position of the core  2  and properly align the core plug inserter  4  and thus the core plug  9 . 
     Referring now to  FIGS. 17-21  the core plug magazine  3  is shown. While the core plug inserter  4  is capable of functioning without the core plug magazine  3 , it would require manual assistance in loading the core plugs  9 . With the addition of the core plug magazine  3  the core plug inserter  4  can insert numerous core plugs  9 , without operator interaction. Operation of the core plug magazine  3  begins with empty left core plug holder  21  and right core plug holder  22 , core plugs  9  (not shown), cylinders  26  retracted and shuttle magazine in its left shifted position. An operator manually loads core plugs  9  into the left core plug holder  21  and right core plug holder  22 . Core plugs  9  fall through the left core plug holder  21 , and onto the recessed pocket of shuttle magazine  31 , but they are stopped by the elevated surface of shuttle magazine  31  when loaded into and right core plug holder  22 . 
     When the cycle begins, sensors  39  and  42  verify both the left and right core plug holders contain core plugs  9  and left cylinder  26  with attached clamp jaw  29  extends to apply pressure against core plug  9  within left core plug holder  21 , securing the next lowest clamped core plug  9  and those immediately above it from further downward movement within the core plug holder  21 . 
     Shuttle magazine  31  then shifts to the right allowing a core plug from right core plug holder  22  to drop into the right recessed magazine pocket of shuttle magazine  31 . Following a brief time delay, right cylinder  26  with attached clamp jaw  29  extends to apply pressure against the core plug  9  within the right core plug holder  22 , securing the next lowest clamped core plug  9  and those immediately above it from further downward movement. 
     At the same time the above movement takes place, shuttle magazine 31  presents in the recessed pocket from left core plug holder  2  core plug  9  for transfer onto disc conveyor  32 . Eject cylinder  34  with attached eject plate  36 , mounted above recessed pocket of shuttle magazine  31  and previously extended, is commanded to retract and pull staged core plug  9  onto disc conveyor  32 . 
     Upon confirmation that eject cylinder  34  has completed its retraction, disc conveyor  32  transports core plug  9  to a predetermined pick position at the conveyor end for capture by the core plug inserter  4 . After a brief delay, eject cylinder  34  returns to its staged position for the next core plug  9  which will be delivered from the right core plug holder  22  using the same sequence of events as were applied to the left core plug holder  21 . 
     The core plug inserter  4  engages the core plug  9  at the predetermined pick point by inserting gripper finger  10  into a hole in the center of core plug  9 , then repositioning the gripper finger  10  at an edge of the center hole of core plug  9 . The core plug inserter  4  then retracts air cylinder  5  which causes gripper finger  10  to clamp the core plug  9  between the gripper finger  10  and the core plug capture flange  11 . Once the core plug  9  is placed inside the core  2 , the core plug inserter  4  returns to the core plug magazine  3  to retrieve another core plug  9 . 
     Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention.