Device for controlling the drawing process in a transfer press

US7827843B2 · kind B2 · utility

Assignee

• Bosch Rexroth Corporation · DE

Inventors

• Stefan Arns · Vingåker, SE
• Helmut Behl · Triefenstein, DE

Key dates

• Filing date: Aug 6, 2004
• Grant date: Nov 9, 2010
• Expiry date: Sep 21, 2027

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B30B15/163
• WIPO field: Machine tools
• WIPO sector: Mechanical engineering

Abstract

A device for controlling the drawing process in a transfer press has two tool parts which act in opposition to one another and between which the workpiece to be deformed is held. One tool part is moved between two reversal points by a mechanical crank mechanism driven at a constant rotational speed. The second tool part is connected to the piston of a hydraulic differential cylinder via a piston rod. The movement of the piston is controlled by the supply of pressure medium into a first chamber and by the discharge of pressure medium out of the second chamber of the differential cylinder. During a first time segment within a range delimited by the first and the second reversal point, the rod-side face of the piston is acted upon by a pressure which is sufficiently high to accelerate the second tool part as that, when the two tool parts impinge one onto the other, both tool parts move virtually at the same speed.