Patent Publication Number: US-2004048549-A1

Title: Device for removing an abrasive disk from a sanding pad

Description:
BACKGROUND OF THE INVENTION  
       [0001] I. Field of the Invention  
       [0002] The present invention relates generally to a device for removing an abrasive disk from a sanding pad.  
       [0003] II. Description of Related Art  
       [0004] There are many manufacturing operations in which a robot manipulates a rotary sander to abrade or sand a manufactured item. These rotary items conventionally include a disk-shaped sanding pad having an upper surface and a lower surface. The upper and lower surfaces of the sanding pad lie in parallel planes to each other and are spaced apart by a predetermined distance equal to the thickness of the sanding pad. An abrasive disk is then detachably secured to the lower surface of the sanding pad by any conventional means, such as hook and pile fasteners or pressure sensitive adhesive.  
       [0005] After prolonged use, the abrasive disk becomes worn and is no longer capable of performing the desired abrasive operation on the workpiece. When this occurs, it is necessary to remove the abrasive disk and replace it with a new abrasive disk.  
       [0006] Previously, there have been no acceptable devices for automatically removing an abrasive disk from a rotary sander when used in a robotic application. Instead, it has been previously necessary to stop the robot and manually remove and thereafter replace the abrasive disk with a fresh abrasive disk. Such a procedure, however, is disadvantageously labor intensive and, therefore, expensive. Furthermore, since the manual replacement of the abrasive disk is necessarily time consuming, such replacement results in a delay in the manufacturing operation thus increasing the cycle time for the manufacturing operation.  
       SUMMARY OF THE PRESENT INVENTION  
       [0007] The present invention provides a device which overcomes all of the above-mentioned disadvantages of manually removing the abrasive disk from a robotic rotary sander.  
       [0008] In brief, the device of the present invention is used with a rotary sander of the type having a disk-shaped sanding pad with an upper surface and a lower surface. The upper and lower surfaces of the sanding pad lie in parallel planes that are spaced apart from each other by a predetermined distance. A drive shaft is attached to and extends coaxially outwardly from the upper surface of the sanding pad while an abrasive disk is removably secured to the lower surface of the sanding pad. Any conventional means, such as hook and pile fasteners or pressure sensitive adhesive, is used to secure the abrasive disk to the lower surface of the sanding pad.  
       [0009] The device of the present invention comprises a frame having a pair of elongated guide rails secured to the frame. Each guide rail has an elongated guide surface adapted to abut against the upper surface of the sanding pad on opposite sides of the pad.  
       [0010] At least one, and preferably two, blades are also secured to the frame so that the blades lie in a plane parallel to the guide surfaces on the guide rails. Furthermore, the blades are spaced from the guide surfaces on the guide rail by a distance equal to the thickness of the sanding pad.  
       [0011] In operation, the rotary sander is manipulated by a robot. When the abrasive disk on the sanding pad becomes worn, the robot moves the sanding pad from an entry end of the guide rails and to an exit end of the guide rails while maintaining the upper surface of the sanding pad in contact with the guide surfaces of the guide rails. In doing so, the blade or blades engage in between the lower surface of the sanding pad and the spent abrasive disk thus removing the spent abrasive disk from the sanding pad. A chute formed in the frame adjacent the exit end of the guide rails transports the spent abrasive disk to a collection area for subsequent disposal.  
       [0012] Since the robot is programmed to slide the sanding pad of the rotary sander through the frame in the above-described fashion, removal of the spent abrasive disk can be rapidly and automatically accomplished. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
     [0013] A better understanding of the present invention will be had upon reference to the following detailed description, when read in conjunction with the accompanying drawing, wherein like reference characters refer to like parts throughout the several views, and in which:  
     [0014]FIG. 1 is a side diagrammatic view illustrating a robot manipulated rotary sander;  
     [0015]FIG. 2 is a front view illustrating a preferred embodiment of the present invention;  
     [0016]FIG. 3 is a top view illustrating the preferred embodiment of the invention;  
     [0017]FIG. 4 is a side diagrammatic view illustrating the operation of the present invention; and  
     [0018]FIG. 5 is a side view illustrating the operation of the present invention. 
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE PRESENT INVENTION  
     [0019] With reference first to FIG. 1, a rotary sander  10  is shown having a disk-shaped sanding pad  12  with an upper surface  14  and a lower surface  16 . The upper and lower surfaces  14  and  16 , respectively, of the sanding pad  12  lie in parallel planes and are spaced apart from each other by a predetermined distance X, i.e. the thickness of the sanding pad  12 .  
     [0020] An abrasive disk  20  is detachably secured to the lower surface  16  of the sanding pad  12 . Any conventional means, such as hook and pile fastener  22  or a pressure sensitive adhesive, may be utilized to secure the abrasive disk  20  to the sanding pad  12 .  
     [0021] A drive shaft  24  extends coaxially outwardly from the upper surface  14  of the sanding pad  12 . This drive shaft  24  is rotatably driven by a motor  26  (illustrated only diagrammatically) and the entire rotary sander  10  is manipulated by a robot  28  (illustrated only diagrammatically).  
     [0022] With reference now to FIGS. 2 and 3, a preferred embodiment of a device  30  for removing the abrasive disk  20  from the sanding pad  12  is shown. The device  30  includes a frame  32  which is mounted in a stationary position in any conventional fashion. Preferably, the frame  32  is made of a rigid material, such as steel.  
     [0023] A pair of elongated guide rails  34  are secured to the frame  32  so that the guide rails  34  are spaced apart and parallel to each other. Furthermore, each guide rail  34  includes an elongated guide surface  36  in which the guide surface  36  on one guide rail  34  is coplanar with the guide surface  36  on the other guide rail  34 . Any conventional means, such as bolts  38 , can be used to secure the guide rails  34  to the frame  32 .  
     [0024] The guide surfaces  36  of the guide rails  34  are adapted to abut against the upper surface  14  (FIG. 1) of the sanding pad  12 . Each guide rail  34  further includes a side  42  which conforms in shape to an outer periphery  44  (FIG. 1) of the sanding pad  12 .  
     [0025] Still referring to FIGS. 2 and 3, at least one and preferably two blades  50  are secured to the frame  32  so that the blades  50  lie in a plane parallel to the plane of the guide surfaces  36  on the guide rails  34 . Furthermore, the blades  50  are spaced from the guide surfaces  36  by the distance X (FIG. 2), i.e. the thickness of the sanding pad  12 .  
     [0026] As best shown in FIG. 3, each blade  50  is preferably tapered at an angle with respect to the longitudinal axis of the guide rails  34 . As such, the blades  50  each include a blade edge  52  which angles from an entry end  54  of the guide rails  34  and toward an exit end  56  of the guide rails  34 .  
     [0027] Although in the preferred embodiment a pair of guide blades  50  are secured to the frame  32 , alternatively, a single guide blade  50  may be employed.  
     [0028] As best shown in FIG. 3, the frame  32  also includes a chute  60  extending downwardly from the blades  50  adjacent the exit end  56  of the guide rails  34 . This chute  60  is open to a collection bin  62  for collecting the spent abrasive disk after removal from the sanding pad  12 .  
     [0029] With reference now to FIGS. 4 and 5, the operation of the present invention will now be described. In FIG. 4, after the abrasive disk  20  becomes worn, the robot  28  moves the sanding disk  12  between the guide rails  34  (only one shown in FIGS. 4 and 5) from the entry end  54  of the guide rails  34  and toward the exit end  56 . Furthermore, the robot  28  maintains the upper surface  14  of the sanding pad  12  in sliding contact with the guide surface  36  on the guide rails. Simultaneously, the sides  42  (FIG. 2) of the guide rails  34  effectively center the sanding pad  12  between the guide rails  34 .  
     [0030] As the robot moves the sanding pad  12  along the guide rails  34 , the leading edge  52  of the blade  50  engages the sanding pad  12  in between its lower surface  16  and the abrasive disk  20 . In doing so, the blade  50  in FIG. 4 initiates the separation of the abrasive disk  20  from the sanding pad  12 .  
     [0031] With reference now to FIG. 5, continued movement of the sanding pad  12  along the guide rails  34  from their entry end  54  and towards their exit end  56  causes the blade  50  to completely remove the abrasive disk  20  from the sanding pad  12 . Upon removal, the spent abrasive disk  20  falls through the chute  60  to the collection bin  62 . The collection bin  62  is periodically emptied as required.  
     [0032] After removal of the spent abrasive disk  20  from the sanding pad  12 , the robot  28  manipulates the sanding pad  20  to attach a fresh abrasive disk to permit continued operation of the rotary sander  10 .  
     [0033] From the foregoing, it can be seen that the device  30  of the present invention provides a simple and yet effective means for rapidly removing a spent abrasive disk from a rotary sander. Since the robot can be programmed to rapidly move the sanding pad between the guide rails  34  in the previously described fashion, the spent abrasive disk  20  can be rapidly removed from the pad  12  thereby minimizing any delay in the abrading operation performed by the robot  28  on the workpiece (not shown).  
     [0034] Having described my invention, however, many modifications thereto will become apparent to those skilled in the art to which it pertains without deviation from the spirit of the invention as defined by the scope of the appended claims.