Stretch forming apparatus

Abstract

A stretch forming apparatus comprises a pair of jaws for pinching both ends of a work, a die placed between the pair of jaws so as to be in contact with the work, a plurality of control axis for change in positions and postures of the jaws and the die, a rotation center line setting unit for making an operator set rotation center lines for the jaws that are for partial stretch of the work by rotation of the jaws, an operation input unit for rotating the jaws by manual operation about the rotation center lines, and a control unit for synchronously controlling the plurality of control axis so that the jaws rotate in accordance with the manual operation by the operator on the operation input unit about the rotation center lines.

1 . A stretch forming apparatus comprising:
 a pair of jaws for pinching end edge side parts of a work having a pair of side edges and a pair of end edges;   a die placed between the pair of jaws so as to be in contact with the work;   a plurality of control axes for change in positions and postures of the jaws and the die;   a rotation center line setting unit for making an operator set rotation center lines for the jaws that are for partial stretch of the work by rotation of the jaws,   an operation input unit for rotating the jaws by manual operation about the rotation center lines set by the operator through the rotation center line setting unit, and   a control unit for synchronously controlling the plurality of control axes so that the jaws rotate, in accordance with the manual operation by the operator on the operation input unit, about the rotation center lines set by the operator through the rotation center line setting unit.   
     
     
         2 . The stretch forming apparatus according to  claim 1 , wherein the rotation center line setting unit is configured so as to set the rotation center lines by positions and postures in jaw coordinate systems predefined for the jaws, and wherein
 the control unit defines the rotation center lines for the jaws that have been defined by the positions and postures in the jaw coordinate systems, by positions and postures in a die coordinate system predefined for the die and controls the control axis for the die and the control axis for the jaws so that the jaws rotate about the rotation center lines defined by the positions and postures in the die coordinate system.   
     
     
         3 . The stretch forming apparatus according to  claim 1 , wherein the rotation center line setting unit sets the rotation center lines so that the rotation center fines pass through crossing points of a side edge of the work and boundaries between parts of the work pinched by the jaws and the remaining parts thereof. 
     
     
         4 . The stretch forming apparatus according to  claim 3 , wherein the rotation center line setting unit sets the rotation center lines that extend in a direction orthogonal to surfaces of the parts of the work pinched by the jaws. 
     
     
         5 . The stretch forming apparatus according to  claim 3 , wherein the rotation center line setting unit sets the rotation center lines along an extending direction of side edges in the parts of the work pinched by the jaws. 
     
     
         6 . The stretch forming apparatus according to  claims 1 , wherein, on condition that there are a plurality of combinations of the control axes that allow the jaws to be rotated about the rotation center lines set by the operator, the control unit selects a combination including the largest number of the control axis of which quantities of operation for rotation of the jaws are smaller than a specified value, and rotates the jaws by controlling the control axes included in the selected combination.