Patent Publication Number: US-10308455-B2

Title: Workpiece conveying apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to a workpiece conveying apparatus, and particularly, relates to a workpiece conveying apparatus for conveying stacked sheet-form workpieces one by one. 
     BACKGROUND ART 
     An example of this type of apparatus is disclosed in Patent Literature 1. According to the background art, a first suction means and a second suction means are arranged on a conveyance path, and generate suction forces in the opposite direction to each other. A paper conveyed out from a paper feeding portion is suctioned by the first suction means, and a paper fed in an overlapping manner on the paper is suctioned by the second suction means. The paper suctioned by the first suction means is supplied to a photoreceptor after passing through the conveyance path. On the other hand, the paper suctioned by the second suction means is discharged into a stacking box after passing through a multi-feeding path branched off from the conveyance path. 
     CITATION LIST 
     Patent Literature 
     [PTL 1] Japanese Unexamined Patent Application Publication No. 2007-246207 
     SUMMARY OF INVENTION 
     Technical Problem 
     However, in the background art, there is a problem in that in order to reuse a paper (sheet-form workpiece) separated by a suction of the second suction means, it is necessary to remount the paper to the paper feeding portion, increasing an operator&#39;s load during operation. 
     Therefore, a primary object of the present invention is to provide a workpiece conveying apparatus capable of conveying sheet-form workpieces one by one without receiving assistance from an operator during operation. 
     Solution to Problem 
     A workpiece conveying apparatus ( 10 : reference numeral corresponding to an embodiment. The same applies hereinafter) according to the present invention includes: a table ( 12 ) on which sheet-form workpieces ( 44 ) are mounted in a stacked state, a guide member ( 14 ) which has an upper surface ( 14   tp ) assisting a conveyance of the workpieces and which is arranged downstream of the table ( 12 ) in a workpiece conveyance direction; and a belt drive mechanism ( 16 ) which has a plurality of pulleys ( 26   a  to  26   d ,  28   a  to  28   d ) each extending in a direction orthogonal to both the workpiece conveyance direction and an up-and-down direction and an endless belt ( 32   a  to  32   d ) wound around the plurality of pulleys, which is arranged above the table and the guide member so as to stride over the table and the guide member, in which a first opening portion (OP 1 ) which generates an upward first suction force is formed on a bottom portion of the belt drive mechanism, a second opening portion (OP 2 ) which generates a downward second suction force is formed on the upper surface of the guide member, and a magnitude of the first suction force exceeds a magnitude of the second suction force. 
     The belt drive mechanism is arranged above the table and the guide member so as to stride over the table and the guide member. Furthermore, the upward first suction force is generated in the first opening portion formed on the bottom portion of the belt drive mechanism. 
     Therefore, a workpiece mounted on the table adheres to the bottom portion of the belt drive mechanism at an upstream end of the first opening portion, and conveyed downstream by the endless belt. When the adhering workpiece reaches a downstream end of the first opening portion, the workpiece is separated from the belt drive mechanism and conveyed along the upper surface of the guide member. 
     In view of the foregoing, the second opening portion which generates the downward second suction force is formed on the upper surface of the guide member. Furthermore, the magnitude of the second suction force falls below the magnitude of the first suction force. 
     Therefore, if two workpieces are multi-fed, although a first workpiece reaches the downstream end of the first opening portion and is conveyed further downstream on the upper surface of the guide member, a second workpiece adheres to the guide member by the second suction force generated in the second opening portion. 
     The second workpiece adhering to the guide member adheres to the bottom portion of the belt drive mechanism at a timing for canceling the multi-feeding with the first workpiece, and is conveyed to the downstream by the endless belt. As a result, it is possible to convey the workpieces one by one without receiving assistance from an operator during operation. 
     It is preferable that the downstream end of the second opening portion is arranged upstream of the downstream end of the first opening portion. As a result, it is possible to ensure that the multi-fed second workpiece adheres to the guide member. 
     It is preferable that a distance from the downstream end of the second opening portion to the upstream end of the first opening portion is shorter than a length from the leading end to the tailing end of the workpiece. 
     If two workpieces are multi-fed, the second workpiece adheres to the guide member at a position displaced toward the downstream from an original position. In view of the foregoing, a distance from the downstream end of the second opening portion to the upstream end of the first opening portion is set to be shorter than the length from the leading end to the tailing end of the workpiece. As a result, it is possible to alleviate a concern that a third workpiece adheres to the endless belt in a state where the second workpiece adheres to the guide member. 
     It is preferable that the belt drive mechanism further includes a motor ( 38   m ) which rotates the plurality of pulleys at a peripheral velocity lower than a peripheral velocity of a conveyance roller ( 46 ) arranged downstream of the guide member. 
     The workpiece released from the endless belt at the downstream end within the workpiece adhering range is conveyed on the upper surface of the guide member and is further conveyed downstream by the conveyance roller. In view of the foregoing, the plurality of pulleys rotate at a peripheral velocity lower than the peripheral velocity of the conveyance roller. As a result, if two workpieces are multi-fed, it is possible to ensure that the first workpiece and the second workpiece are separated. 
     It is preferable that the motor intermittently rotates the plurality of pulleys, based on a positional relationship between the workpiece conveyed by the belt drive mechanism and the conveyance roller. By intermittently rotating the plurality of pulleys, a workpiece conveyance operation is stabilized. 
     Advantageous Effects of Invention 
     According to the present invention, it is possible to convey the workpieces one by one without receiving assistance from an operator during operation. 
     The above-described object, other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiment when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view illustrating a state obtained when a workpiece conveying apparatus of the present embodiment is viewed obliquely from above. 
         FIG. 2  is a perspective view illustrating a state obtained when a guide member included in the workpiece conveying apparatus is viewed obliquely from above. 
         FIG. 3  is a perspective view illustrating a state obtained when a belt drive mechanism included in the workpiece conveying apparatus is viewed from obliquely below. 
         FIG. 4  is an exploded view illustrating the guide member illustrated in  FIG. 2  in an exploded state. 
         FIG. 5  is an exploded view illustrating the belt drive mechanism illustrated in  FIG. 3  in an exploded state. 
         FIG. 6  is a sectional view illustrating a certain section of the workpiece conveying apparatus. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     With reference to  FIG. 1 , a workpiece conveying apparatus  10  of the present embodiment is configured by a table  12 , a guide member  14 , and a belt drive mechanism  16 . The table  12  is arranged upstream in a work conveyance direction and the guide member  14  is arranged downstream in the work conveyance direction. Furthermore, the belt drive mechanism  16  is arranged above the table  12  and the guide member  14  so as to stride over the table  12  and the guide member  14 . 
     On the table  12 , sheet-form workpieces  44 ,  44 , . . . like paper (see  FIG. 6 ) is mounted in a stacked state. A main surface of the mounted workpiece  44  is formed in a rectangular shape, and a longer side of the rectangular shape extends along a sheet conveying direction. In the present embodiment, an X axis, a Y axis, and a Z axis are assigned to a length direction, a width direction, and a thickness direction of the thus mounted workpiece  44 , respectively. 
     It is noted that a positive side in an X-axis direction corresponds to the upstream in the workpiece conveyance direction and a negative side in the X-axis direction corresponds to the downstream in the workpiece conveyance direction. Furthermore, the positive side in a Z-axis direction corresponds to an upward direction and a negative side in the Z-axis direction corresponds to a downward direction. 
     With reference to  FIG. 2  and  FIG. 4 , the guide member  14  includes a base plate  18 , a blower stay  22  attached to the base plate  18 , and a blower  20  held by the blower stay  22 . 
     The base plate  18  has an upper surface  18   tp  which assists conveyance of the workpiece  44  by the belt drive mechanism  16 , a side surface (wall surface)  18   sd  which regulates a positional displacement of the workpieces  44 ,  44 , . . . stacked on the table  12 , and further includes a slope  18   slp  which is provided at a position connecting the upper surface  18   tp  and the side surface  18   sd  to cancel a deflection of the workpiece  44  during conveyance. 
     The base plate  18  is also formed with a cutout portion  18   ct  which partially cuts out the upper surface  18   tp , the slope  18   slp , and the side surface  18   sd  at an end portion at the positive side in a Y-axis direction. The blower  20  and the blower stay  22  holding the blower  20  are fit into this cutout portion  18   ct.    
     The blower stay  22  also has an upper surface  22   tp  and a side surface  22   sd . In a state of being fit into the cutout portion  18   ct , the upper surface  22   tp  is flush with the upper surface  18   tp  and the side surface  22   sd  is substantially flush with the side surface  18   sd . An upper surface  14   tp  of the guide member  14  (see  FIG. 2 ) is formed by the upper surfaces  22   tp  and  18   tp.    
     A second opening portion OP 2  is formed on the upper surface  22   tp  and a third opening portion OP 3  is formed on the side surface  22   sd . Particularly, the second opening portion OP 2  is formed of a plurality of through holes which extend linearly in the X-axis direction and are arrayed in the Y-axis direction. The blower  20  generates a downward suction force in the second opening portion OP 2  to ensure that the workpiece  44  being conveyed adheres to the upper surface  22   tp . A part of air suctioned through the second opening portion OP 2  is exhausted from the third opening portion OP 3 . The workpieces  44 ,  44 , . . . stacked on the table  12  are separated by the air exhausted from the third opening portion OP 3 . 
     Strip-like friction materials (urethane plates)  24   a  and  24   b  are also affixed to the upper surface  22   tp . The friction material  24   a  extends along the X axis on a negative-side position in the Y-axis direction relative to the second opening portion OP 22 , and the friction material  24   b  extends along the X axis on a positive-side position in the Y-axis direction relative to the second opening portion OP 22 . The positional displacement of the workpiece  44  adhering to the upper surface  22   tp  is suppressed by the friction materials  24   a  and  24   b  affixed in this manner. 
     It is noted that although not illustrated in  FIG. 4 , a workpiece alignment  42  is affixed on the side surface  18   sd . The workpiece alignment  42  is a member which aligns the workpieces  44 ,  44 , . . . stacked on the table  12  and extends a positive-side end portion in the Y-axis direction into the Z-axis direction. 
     With reference to  FIG. 3  and  FIG. 5 , the belt drive mechanism  16  includes pulley holders  30   a  and  30   b  arranged with a spacing therebetween in the X-axis direction. Specifically, the pulley holder  30   a  is arranged on the positive side in the X-axis direction and the pulley holder  30   b  is arranged on the negative side in the X-axis direction. However, an arrangement in each of the Y-axis direction and the Z-axis direction matches between the pulley holders  30   a  and  30   b.    
     Large diameter pulleys  26   a ,  26   d , and a small diameter pulley  28   a  are held by the pulley holder  30   a , and the large diameter pulleys  26   b ,  26   c  and the small diameter pulley  28   b  are held by the pulley holder  30   b.    
     Each rotational axis of the held large diameter pulleys  26   a  to  26   d  and the small diameter pulleys  28   a  and  28   b  extends along the Y axis. Furthermore, an arrangement in the Z-axis direction (height direction) matches between the large diameter pulleys  26   a  and  26   b , matches between the large diameter pulleys  26   c  and  26   d , and matches between the small diameter pulleys  28   a  and  28   b . However, the large diameter pulleys  26   c  and  26   d  are arranged at a higher position than the large diameter pulleys  26   a  and  26   b , and the small diameter pulleys  28   a  and  28   b  are arranged at a slightly lower position than the large diameter pulleys  26   a  and  26   b.    
     A case  34  is configured by an upper-side case member  34   up  having a ceiling surface on which through holes HL 1   a  and HL 1   b  are formed, a bottom-side case member  34   btm  having a bottom surface on which the first opening portion OP 1  is formed, and a partition plate  34   sp  housed in the bottom-side case member  34   btm.    
     More specifically, the through holes HL 1   a  and HL 1   b  are common in size and arrayed in the X-axis direction. The through hole HL 1   a  is arranged on the positive side in the X-axis direction and the through hole HL 1   b  is arranged on the negative side in the X-axis direction. 
     The partition plate  34   sp  is arranged on the bottom-side case member  34   btm  so as to extend, along the Y axis, between the through holes HL 1   a  and HL 1   b . As a result, an inner space of the case  34  is partitioned into a space SP 1   a  beneath the through hole HL 1   a  and a space SP 1   b  beneath the through hole HL 1   b.    
     The first opening portion OP 1  includes a plurality of through holes linearly extending in the X-axis direction and arrayed in the Y-axis direction. A width of each through hole is larger in the upstream (the space SP 1   a  side) of the partition plate  34   sp  and narrower in the downstream (the space SP 1   b  side) of the partition plate  34   sp.    
     A blower  36   a  is arranged on the ceiling surface of the upper-side case member  36   up  so as to cover the through hole HL 1   a . Furthermore, a blower  36   b  has the same size and capability as the blower  36   a  and is arranged on the ceiling surface of the upper-side case member  34   up  so as to cover the through hole HL 1   b . The blowers  36   a  and  36   b  arranged in such a way generate the upward suction force in the first opening portion OP 1 . 
     The upward suction force generated in the first opening portion OP 1  exceeds the downward suction force generated in the second opening portion OP 2 . Furthermore, as illustrated in  FIG. 6 , the downstream end of the first opening portion OP 1  is arranged downstream of the second opening portion OP 2 . More precisely, the downstream end of the first opening portion OP 1  is arranged downstream of the both downstream end and upstream end of the second opening portion OP 2 . Furthermore, a distance from the downstream end of the second opening portion OP 2  to the upstream end of the first opening portion OP 1  is less than a length from a leading end to a tailing end of the workpiece  44 . 
     Returning to  FIG. 5 , a height size of the case  34  is equal to or less than half a height size of each of the pulley holders  30   a  and  30   b , and a height size of each of the blowers  36   a  and  36   b  is also equal to or less than half a height size of each of the pulley holders  30   a  and  30   b . Furthermore, a width of the case  34  is slightly less than each width of the pulley holders  30   a  and  30   b , and a length of the case  34  is slightly less than a spacing between the small diameter pulleys  28   a  and  28   b.    
     The case  34 , and the blowers  36   a  and  36   b  are arranged between the pulley holders  30   a  and  30   b  so that a height position of the bottom surface of the bottom-side case member  34   btm  matches a height position of the lower end of the pulley holders  30   a  and  30   b . As a result, the case  34  is interposed between the small diameter pulleys  28   a  and  28   b , and further interposed between the large diameter pulleys  26   a  and  26   b . Furthermore, the height position of the upper surface of each of the blowers  36   a  and  36   b  is lower than the height position of the upper surface of the pulley holders  30   a  and  30   b.    
     The endless belts  32   a  to  32   d  are wound around the large diameter pulleys  26   a  to  26   d  and the small diameter pulleys  28   a  and  28   b . The wound endless belts  32   a  to  32   d  are arrayed in an order of “ 32   a ”, “ 32   b ”, “ 32   c ”, and “ 32   d ” as viewed from the negative side to the positive side in the Y-axis direction. The case  34 , and the blowers  36   a  and  36   b  are housed inside the endless belts  32   a  to  32   d  wound in this manner. 
     A motor unit  38  having a drive motor  38   m  is also attached to the pulley holder  30   b . The drive motor  38   m  rotates the large diameter pulley  26   b  in a clockwise direction as viewed from the negative side in the Y-axis direction. Alongtherewith, the endless belts  32   a  to  32   d  rotate in the same direction. 
     With reference to  FIG. 6 , a distance from the workpiece  44  of a top layer mounted on the table  12  to the bottom surface of the belt drive mechanism  16  is detected by a sensor  40  provided in a proximity of the large diameter pulley  26   a . The table  12  moves up and down so that a detected distance indicates a designated value. That is, the table  12  gradually ascends each time the workpiece  44  is conveyed out. 
     The upward suction force is generated in the first opening portion OP 1 , and thus, the workpiece  44  of the top layer adheres to the endless belts  32   a  to  32   d  and is conveyed downstream. Furthermore, the upward suction force generated in the first opening portion OP 1  exceeds the downward suction force generated in the second opening portion OP 2 , and thus, the workpiece  44  adhering to the endless belts  32   a  to  32   d  reaches the small diameter pulley  28   b  without contacting with the upper surface  14   tp  of the guide member  14 , and then, is conveyed downstream on the upper surface  14   tp  of the guide member  14 . 
     A conveyance roller  46  is provided at a position downstream of the belt drive mechanism  16 . When the leading end of the workpiece  44  reaches the conveyance roller  46 , the workpiece  44  is wound up by the conveyance roller  46  and is conveyed further downstream. 
     The positional relationship between the workpiece  44  being conveyed and the conveyance roller  46  is detected by a sensor  48  provided downstream of the conveyance roller  46 , and the drive motor  38   m  intermittently rotates the large diameter pulley  26   b , based on a detection result of the sensor  48 . That is, a rotation of the endless belts  32   a  to  32   d  stops immediately after a leading edge of the workpiece  44  has passed through the conveyance roller  46  and resumes immediately after a trail edge of the workpiece  44  has been departed from the conveyance roller  46 . As a result, on the average, a peripheral velocity of the large diameter pulley  26   b , by extension, the endless belts  32   a  to  32   d , is less than a peripheral velocity of the conveyance roller  46 . 
     In a state where the workpieces  44 ,  44 , . . . are stacked on the table  12 , there may be a case that the second workpiece  44  is attached to the first workpiece  44  by a static electricity, for example, and the two workpieces  44  and  44  are multi-fed. However, although the first workpiece  44  reaches the downstream end of the first opening portion OP 1  and is further conveyed downstream on the upper surface  14   tp  of the guide member  14 , the second workpiece  44  adheres to the guide member  14  by the suction force generated in the second opening portion OP 2 . 
     The second workpiece  44  adhering to the guide member  14  adheres to the bottom surface of the belt drive mechanism  16  at a timing for canceling the multi-feed with the first workpiece  44 , and is conveyed downstream by the endless belts  32   a  to  32   d . Therefore, the workpiece  44  is supplied to the conveyance roller  46  one by one even if the two workpieces  44  and  44  are overlapped and conveyed out from the table  12 . 
     As understood from the above-described description, the sheet-form workpieces  44 ,  44 , . . . are mounted in a stacked state on the table  12 . The guide member  14  has the upper surface  14   tp  assisting conveyance of the workpiece  44  and is arranged downstream of the table  12  in the workpiece conveyance direction. The belt drive mechanism  16  has the large diameter pulleys  26   a  to  26   d  and the small diameter pulleys  28   a  and  28   b  each extending in the direction orthogonal both to the workpiece conveyance direction and the up-and-down direction, and the endless belts  32   a  to  32   d  wound around these pulleys, and is arranged above the table  12  and the guide member  14  so as to stride over the table  12  and the guide member  14 . The first opening portion OP 1  is formed on the bottom portion of the belt drive mechanism  16  to generate the upward suction force. The second opening portion OP 2  is formed on the upper surface  14   tp  of the guide member  14  to generate the downward suction force. Here, the magnitude of the suction force generated in the first opening portion OP 1  exceeds the magnitude of the suction force generated in the second opening portion OP 2 . 
     Again, the workpiece  44  mounted on the table  12  adheres to the bottom portion of the belt drive mechanism  16  at the upstream end of the first opening portion OP 1  and is conveyed downstream by the endless belts  32   a  to  32   d . When the adhering workpiece  44  reaches the downstream end of the first opening portion OP 1 , the workpiece  44  departs from the belt drive mechanism  16  and is further conveyed downstream along the upper surface  14   tp  of the guide member  14 . 
     If the two workpieces  44  and  44  are multi-fed, the first workpiece  44  reaches the downstream end of the first opening portion OP 1 , and is further conveyed downstream on the upper surface  14   tp  of the guide member  14 . On the other hand, the second workpiece  44  adheres to the guide member  14  by the suction force generated in the second opening portion OP 2 . 
     The second workpiece  44  adhering to the guide member  14  adheres to the bottom portion of the belt drive mechanism  16  at a timing for canceling the multi-feed with the first workpiece  44 , and is conveyed downstream by the endless belts  32   a  to  32   d . As a result, it is possible to convey the workpiece  44  one by one without receiving assistance from an operator during operation. 
     Furthermore, the downstream end of the first opening portion OP 1  is arranged downstream of the downstream end of the second opening portion OP 2 . As a result, it is possible to ensure that the second multi-fed workpiece  44  adheres to the guide member  14 . 
     Furthermore, in view of the second multi-fed workpiece  44  being adhered to the guide member  14  at a position displaced toward the downstream, the distance from the downstream end of the second opening portion OP 2  to the upstream end of the first opening portion OP 1  is set to be shorter than the length from the leading end to the tailing end of the workpiece  44 . As a result, it is possible to alleviate a concern that the third workpiece  44  adheres to the endless belts  32   a  to  32   d  in a state where the second workpiece  44  adheres to the guide member  14 . 
     It is noted that in the present embodiment, although the first opening portion OP 1  is formed on the bottom surface of the bottom-side case member  34   btm , it may be possible that the case  34  is omitted and the endless belts  32   a  to  32   d  is replaced by a single endless belt having a countless number of through holes. 
     REFERENCE SIGNS LIST 
     
         
         
           
               10  . . . Workpiece conveying apparatus 
               12  . . . Table 
               14  . . . Guide member 
               16  . . . Belt drive mechanism 
               26   a  to  26   d  . . . Large diameter pulley 
               28   a ,  28   b  . . . Small diameter pulley 
               32   a  to  32   d  . . . Endless belt 
               38   m  . . . Drive motor 
               44  . . . Workpiece 
               46  . . . Conveyance roller 
             OP 1  . . . First opening portion 
             OP 2  . . . Second opening portion