Patent ID: 7124614

Claim:
Arrangement in a sheet metal working tool comprising an upper moveable tool part, a lower tool part and a holder part designed, during a sheet metal working operation in which a sheet metal fabrication is subjected to working between the tool parts, to hold the sheet metal fast to the moveable tool half in a working position by means of spring elements supporting the holder, and comprising members designed, in a movement from a predetermined basic position at a distance from the working position, to impart a speed component to the holder part, wherein the said member comprises a system of interconnected and articulated links wherein each link comprises at least one leg, connected to the holder part, of which a first link is designed to be acted upon by the movement of the upper tool half, so that due to the articulated connection between the links a power-transmitting operative connection is produced between the upper tool half and the holder part, the power-transmitting operative connection operating as a single linkage arm, the length of at least one leg of which being variable over time so that after completing the movement from the basic resting position to the starting position of a working operation the holder part has substantially the same speed as the moveable tool part and a corresponding retardation in the subsequent ascending movement, and said member further having a push rod actuatable by the tool upper part, a stop on the push rod being designed to act on a roller device arranged in the first link, which is articulated about a first joint in said member, the first link being connected to one end of a second link of the interconnected and articulated links, which is articulated about a second joint and the other end of which interacts with a piston rod of a spring mechanism, a support part, by way of a roller device, engaging throughout with the second link closely adjacent to the said one end of the second link.