Workpiece feeding apparatus

Abstract

A plurality of working blocks (A, B) are connected by rails ( 18 ). A branched transporting mechanism ( 100 ) is disposed at the intersections of the rails ( 18 ). A transportation vehicle ( 300 ) of non-self-propelled type moves on the rails ( 18 ) by the driving power of a wire ( 20 ). A placement table ( 450 ) is positioned in the vicinity of the working blocks (A, B). The placement table ( 450 ) moves up and down with a workpiece placed thereon between the transportation vehicle ( 300 ) and the working blocks (A, B). Transfer of work is effected by moving the placement table ( 450 ) up and down, and adjusting the height of the placement table ( 450 ) to the height of the transportation vehicle ( 300 ) or to the height of the working blocks (A, B). Further, the transportation vehicle ( 300 ) has a wire gripping mechanism ( 350 ) for gripping the wire ( 20 ), and workpiece placement plates ( 326 a, 326 b ) for placing the workpiece thereon.

1 . A workpiece feeding apparatus having a wire gripping device for bringing a non-self-propelled transportation vehicle into engagement with a moving wire to feed the transportation vehicle to a desired position and releasing said transportation vehicle from the wire at said desired position, 
 said wire gripping device having first clamp means and second clamp means mounted on said transportation vehicle;    wherein said first clamp means has a pair of first eccentric cams, first urging means for moving said first eccentric cams to bring cam surfaces thereof closely to each other when said wire rotates in said normal direction, and a pair of first gears for rotating said first eccentric cams in synchronism with each other; and    said second clamp means has a pair of second eccentric cams, second urging means for moving said second eccentric cams to bring cam surfaces thereof closely to each other when said wire rotates in said reverse direction, and a pair of second gears for rotating said second eccentric cams in synchronism with each other;    wherein said first clamp means clamps said wire when said wire rotates in a normal direction and said second clamp means unclamps said wire when said wire rotates in said normal direction, and said first clamp means unclamps said wire when said wire rotates in a reverse direction and said second clamp means clamps said wire when said wire rotates in said reverse direction.    
   
   
       2 . A workpiece feeding apparatus according to  claim 1 , further comprising a pair of first cam spreading means for forcibly spreading said first eccentric cams away from each other, and a pair of second cam spreading means for forcibly spreading said second eccentric cams away from each other.  
   
   
       3 . A workpiece feeding apparatus according to  claim 1 , wherein said first clamp means comprises: 
 a pair of first grip members for gripping said wire over a predetermined range;    a pair of first rotational members for displacing said first grip members toward or away from said wire while keeping said first grip members substantially parallel to said wire; and    first urging means for urging said first rotational members in a predetermined direction to bring said first grip members closely to each other at all times,    wherein said second clamp means comprises:    a pair of second grip members for gripping said wire over a predetermined range;    a pair of second rotational members for displacing said second grip members toward or away from said wire while keeping said second grip members substantially parallel to said wire; and    second urging means for urging said second rotational members in a predetermined direction to bring said second grip members closely to each other at all times.    
   
   
       4 . A workpiece feeding apparatus according to  claim 3 , wherein said first clamp means has a first parallel crank mechanism for keeping said first grip members substantially parallel to said wire, and said second clamp means has a second parallel crank mechanism for keeping said second grip members substantially parallel to said wire.  
   
   
       5 . A workpiece feeding apparatus according to  claim 3 , wherein said first clamp means has a pair of first gears for rotating said first rotational members in synchronism with each other, and said second clamp means has a pair of second gears for rotating said second rotational members in synchronism with each other.  
   
   
       6 . A workpiece feeding apparatus according to  claim 3 , wherein said first clamp means has a pair of first wire grip release means for forcibly releasing said wire from said first grip members, and said second clamp means has a pair of second wire grip release means for forcibly releasing said wire from said second grip members.