Drawing installation for a press
First Claim
1. A drawing installation for a press, comprising a mechanically actuated drawing ram means, a sheet metal holder means producing a holding force acting on a sheet metal member opposite a drawing direction by way of a pressure medium-actuated piston rod means in a fixed pressure cylinder means, the piston rod means being operatively connected with a pressure piton means having operating surface means acted upon in the drawing direction, said pressure cylinder means forming a pressure space around the operating surface means of the pressure piston means, control means operating in dependence on ram travel and operable to pre-accelerate the sheet metal holder means in the drawing direction by the piston pressure means prior to contact of the drawing ram means on the sheet metal holder means by connecting the operating surface means of the pressure piston means with hydraulic liquid, said control means including a pre-acceleration cylinder means having pressure quantity space means, a pressure space means and a pressure piston separating the pressure quantity space means from the pressure space means, a follow-up control means, hydraulic fluid reservoir, the pressure space of said pressure cylinder means being in hydraulic fluid-communication with the pressure quantity space means and being operable to be brought into hydraulic fluid communication with the reservoir of hydraulic fluid by a follow-up control means upon termination of the pre-acceleration of the sheet metal holder means by the pressure piston means.
1 Assignment
0 Petitions
Accused Products
Abstract
A drawing installation for a press which has to produce the holding force for the counter-holding during the drawing. The drawing ram displaces the sheet metal part and the sheet metal holder against the holding force to be produced by the drawing installation and must additionally overcome the inertia forces which occur as a result of the acceleration of the parts of the drawing installation at the beginning of the deformation of the sheet metal part. In order to avoid the forces which occur thereby impact-like, the piston rod transmitting the holding force is pre-accelerated in the drawing direction prior to the contact of the drawing ram on the sheet metal holder. The piston rod has an operating surface adapted to be acted upon in the drawing direction. The pressure space coordinated to the operating surface is adapted to be connected with a pressure quantity space of a pre-acceleration cylinder and with a reservoir by way of a follow-up control. The control with respect to time of the pre-acceleration cylinder and of the refill from the reservoir takes place in dependence on the movement of the drawing ram, controlled by the press. The drawing installation is utilizable in presses with mechanically driven drawing ram and a sheet metal holder holding the sheet metal part.
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Citations
8 Claims
- 1. A drawing installation for a press, comprising a mechanically actuated drawing ram means, a sheet metal holder means producing a holding force acting on a sheet metal member opposite a drawing direction by way of a pressure medium-actuated piston rod means in a fixed pressure cylinder means, the piston rod means being operatively connected with a pressure piton means having operating surface means acted upon in the drawing direction, said pressure cylinder means forming a pressure space around the operating surface means of the pressure piston means, control means operating in dependence on ram travel and operable to pre-accelerate the sheet metal holder means in the drawing direction by the piston pressure means prior to contact of the drawing ram means on the sheet metal holder means by connecting the operating surface means of the pressure piston means with hydraulic liquid, said control means including a pre-acceleration cylinder means having pressure quantity space means, a pressure space means and a pressure piston separating the pressure quantity space means from the pressure space means, a follow-up control means, hydraulic fluid reservoir, the pressure space of said pressure cylinder means being in hydraulic fluid-communication with the pressure quantity space means and being operable to be brought into hydraulic fluid communication with the reservoir of hydraulic fluid by a follow-up control means upon termination of the pre-acceleration of the sheet metal holder means by the pressure piston means.
Specification