Bosch Rexroth Ag

Robert Boschgmbh

Helmut Behl

Jörg Dantlgraber

Michael Reinert

Bruno Schneider

Frank Hofmann

Stefan Arns

Karl J H Cords

Helmut Etzel

Dragoljub Djenadija

Marek Chmiel

Holger Englert

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.

Device for controlling the drawing process in a transfer press

An unlockable non-return valve reduces the tendency of the poppet piston to jam by providing a first insert that has a guide diameter for the poppet piston over just a short section of its end side facing the piston collar, and wherein a supporting ring is arranged axially between the high-pressure seal and the first insert in a receiving element, the diameter of which is substantially smaller than the outside diameters of the inserts, the supporting ring likewise being produced from a metallic material having good sliding properties and being produced with a narrow clearance from the end section of the poppet piston and with a large radial clearance from the receiving element.

Unlockable non-return valve for very high system pressures

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Triefenstein, Germany

Helmut Behl