Control system for a walking beam assembly of a forging press

Abstract

The walking beam assembly of the forging presses operates in several movement phases including a lifting movement, advance movement, lowering movement, opening movement, return movement, and closing movement. Step motors control driving members which perform individual moving processes in the individual movement phases. In turn, driving member processors drive the step motors by frequencies changing with time. When the velocity or frequency of the step motors are plotted on the ordinate of a graph and time along the abscissa of the graph, a trapezoidal graph form is produced along the time (t) line of the graph for each of the movement phases. Each trapezoidal form includes a rising flank and a falling flank with some of the flanks for adjacent driving member phase movement overlapping in time. The opening and return movement phases form a fixed cycle having a length predetermined and constant for all cycle lengths. The remaining phases form a varicycle having a length that changes with the length of the cycle time. During the fixed cycle, the walking beam assembly or manipulator does not move any workpieces. The varicycle can be adjusted to the respected mass of the workpieces. For workpieces having a large mass, the times for acceleration and delay are reduced.