Press with hydraulic overload safety device and ram weight counterbalancing mechanism

US4011809A · kind A · utility

Assignee

• L. Schuler GmbH · DE

Inventors

• Eugen Waller · Göppingen, DE
• Wolfram Buchler · Donzdorf, DE
• Rolf Kellenbenz
• Franz Schneider · Göppingen, DE
• Burkhard Schumann · Ottenbach, DE

Key dates

• Filing date: Mar 24, 1975
• Grant date: Mar 15, 1977
• Expiry date: Mar 24, 1995

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B30B15/284
• WIPO field: Machine tools
• WIPO sector: Mechanical engineering

Abstract

A press having mechanical drive elements acting on the ram through at least one pressure cushion serving as a hydraulic overload safety device, at least one cylinder-piston unit operating under the effect of a compressed fluid for counterbalancing the weight of the ram associated with an upper die of the press, and a control system for adjusting fluid pressure in the cylinder-piston unit to a value for counterbalancing the weight. The control system includes a pressure relief valve and a pressure meter associated with the pressure cushion wherein the meter detects the pressure in the pressure cushion in a measuring range including a predetermined value. An actuating member serves for initiating a counterbalancing operation which includes operation of the pressure relief valve and control of supply and discharge valves for supplying and discharging fluid to and/or from the cylinder-piston unit.