Transfer device on a press

Abstract

The present invention relates to a device on a press and to a method for incrementally conveying workpieces in a longitudinal direction from a receiving station through at least one tooling station of the press with the aid of conveying means for the workpieces, which conveying means are moved back and forth in cycles and in synchrony with the movement of the press in the longitudinal direction, as well as in a transverse direction substantially perpendicular thereto in order to grip or release the workpieces. The conveying means are here moved in the longitudinal direction by means of an external drive unit which is merely synchronized with the movement of the press. The motor-powered external drive unit is mechanically coupled to the conveying means in such a way that the conveying means can be moved back and forth without reversing the rotation of the external drive unit.

1 . A device on a press, having a predetermined movement thereof, for incrementally conveying at least one workpiece in a longitudinal direction from a receiving station through at least one tooling station of the press used in connection with a means for conveying the at least one workpiece, the conveying means being moved back and forth in cycles in the longitudinal direction, as well as in a transverse direction substantially perpendicular thereto in order to grip or release the at least one workpiece, the device comprising: 
 an external drive unit capable of rotational movement in synchrony with the movement of the press, wherein said rotational movement is driven by a motor; and    a coupling attached to a portion of the conveying means and to a portion of said external drive unit;    wherein the conveying means are moved in the longitudinal direction using said external drive unit, and said coupling is structured such that said external drive unit is mechanically connected to the conveying means in such a way that the conveying means can be moved back and forth in synchrony with the movement of the press without reversing the rotation of the external drive unit.    
   
   
       2 . The device as claimed in  claim 1 , wherein the mechanical coupling between external drive unit and conveying means is a mechanical gear, including a mechanical cam gear.  
   
   
       3 . The device as claimed in  claim 2 , wherein said gear is a worm gear.  
   
   
       4 . The device as claimed in  claim 1 , wherein the movement of said external drive unit is coupled by means of an incremental angle transducer to the movement of the press, including to the movement of an eccentric shaft of the press.  
   
   
       5 . The device as claimed in  claim 1  further including means for allowing said external drive unit to be operated at different speeds in dependence on a feed cycle of the press.  
   
   
       6 . The device as claimed in  claim 1 , wherein said external drive unit includes a servo motor.  
   
   
       7 . The device as claimed in  claim 1 , wherein the movement of the conveying means in the transverse direction for the release of the at least one workpiece is derived, from the movement of the press by direct mechanical coupling thereto.  
   
   
       8 . The device as claimed in  claim 1 , wherein the movement of the conveying means for the grabbing of the at least one workpieces in the transverse direction is effected by an external drive unit.  
   
   
       9 . The device as claimed in  claim 1 , wherein the speed of the longitudinal movement of the conveying means is variable within predetermined limits by controlling the speed of the external drive unit.  
   
   
       10 . The device as claimed in  claim 1 , wherein the drive of the conveying means in the transverse direction for the release of the at least one workpiece is derived from the movement of a press ram of the press via a mechanical cam system.  
   
   
       11 . The device as claimed in  claim 1 , wherein the conveying means include transfer bars which extend in a longitudinal direction on both sides of a receiving station and of at least one tooling station and which includes grabs for the at least one workpiece.  
   
   
       12 . A method for incrementally conveying at least one workpiece on a press having a predetermined rotation thereof in a longitudinal direction from a receiving station through at least one tooling station of the press in connection with a means for conveying the at least one workpiece, wherein the conveying means are moved back and forth in cycles in the longitudinal direction, as well as in a transverse direction substantially perpendicular thereto in order to grip or release the at least one workpiece, the method comprising: 
 providing a device including;    a rotating external drive unit, wherein the rotation of said external drive unit is driven by a motor and is synchronized with the movement of the press; and    a coupling attached to a portion of the conveying means and to a portion of said external drive unit; and    moving the conveying means in the longitudinal direction and in synchrony with the movement of the press using said external drive unit such that the back and forth movement of the conveying means are driven by said external drive unit without reversing the rotation of the external drive unit.    
   
   
       13 . The method as claimed in  claim 12 , wherein the external drive unit is run at a constant rotation speed and with constant direction of rotation.  
   
   
       14 . The method as claimed in  claim 12 , wherein the external drive unit is operated in dependence on the feed cycle at varying rotation speed with constant direction of rotation.  
   
   
       15 . The method as claimed in  claim 14 , wherein a rotation speed of said external drive unit is varied in sections of a feed cycle of the press in which the conveying means perform no longitudinal movement.  
   
   
       16 . The method as claimed in  claim 15 , wherein the rotation speed of said external drive unit is varied in such a way that a feed angle is reduced with respect to running behavior at constant rotation speed of the external drive unit.  
   
   
       17 . The method as claimed in  claim 16 , wherein, in the feed operation, an increased, constant rotation speed is operated, and in that, in sections of the feed cycle in which the conveying means perform no longitudinal movement, the rotation speed is initially decreased and then accelerated to a value which is relevant to the next section.  
   
   
       18 . The method as claimed in  claim 12 , wherein the press is operated at a stroke rate of more than 200 strokes/min.  
   
   
       19 . The device as claimed in  claim 2 , wherein said mechanical gear is a mechanical cam gear.  
   
   
       20 . The device as claimed in  claim 4 , wherein said movement of the movement of the external drive unit is coupled by means of an incremental angle transducer to the movement of an eccentric shaft of the press.  
   
   
       21 . The method of  claim 14 , wherein the rotation speed of said external drive unit is varied in such a way that a feed angle is reduced with respect to running behavior at constant rotation speed of the external drive unit.  
   
   
       22 . The method as claimed in  claim 21 , wherein, in the feed operation, an increased, constant rotation speed is operated, and in that, in sections of the feed cycle in which the conveying means perform no longitudinal movement, the rotation speed is initially decreased and then accelerated to a value which is relevant to the next section.  
   
   
       23 . The method as claimed in  claim 18 , wherein the press is operated at a stroke rate of at least 300 strokes/min.