System for controlling energy characteristics of power press - has pneumatic-hydraulic cylinders on each side of ram to balance effects of ram mass

摘要

In a conventional power press drive energy is normally lost in the form of heat emitted by the clutch and brake during the press working cycle. In the invention two balancing cylinders are fastened to the press frame on each side of the press ram (8). The piston rod (27) passes through the bore of bracket (25) extending from the ram and has a cushioned ram abutment collar (26, 19) at its end. The upper chamber (31) of the balancing cylinder is connected through control valve (20) to the pneumatic low pressure side of the intensifier (30) and the lower chamber (18) is connected to the hydraulic high pressure side of the intensifier under control of valves (29). At the start of the press cycle, the ram accelerates from top dead centre until the abutment collar is contacted, when it moves against the pressure of oil in the lower chamber of the balancing cylinder. Finally, the full forming torque is applied by clutch (2). The position of contact between the ram and abutment collar is adjustable through valves (20) and (29). ADVANTAGE - Simple method of balancing effect of ram mass and achieving more efficient use of energy. Reduced wear of clutch and brake. Reduced noise. Balancing function easily adjustable.