Hydraulic drive

US7370569B2 · kind B2 · utility

Assignee

• Bosch Rexroth Corporation · DE

Inventors

• Stefan Schmidt · Aalen, DE
• Rolf Heidenfelder · Hafenlohr, DE

Key dates

• Filing date: May 14, 2004
• Grant date: May 13, 2008
• Expiry date: Jan 10, 2025

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F15B2211/6653
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

What is disclosed is a hydraulic drive mechanism for a blanking or forming machine comprising a working cylinder having several pressure chambers, the piston of which acts directly or indirectly on a workpiece to be processed, wherein at least one pressure chamber of the working cylinder for retracting and extending the piston is adapted to be subjected to a tank pressure or a supply pressure via a continuously adjustable valve, and comprising a valve assembly arranged upstream of the continuously adjustable valve, whereby an inlet port of the continuously adjustable valve may be subjected to a higher or lower supply pressure, wherein the valve assembly comprises a switching valve adapted to be switched over between a basic position and a switching position in dependence on the load pressure at the working cylinder in order to tap the supply pressure from a low-pressure source or from a high-pressure source.