Abstract: The drawing tool comprises a hydraulic element for deriving from the movement of the blank holder a simultaneous, oppositely directed movement of the drawing punch. The hydraulic element comprises a centrally disposed working piston, an annular piston, which surrounds that working piston, and a cylinder, which surrounds the annular piston. The working piston and the annular piston are adapted to be supplied with pressure fluid from first and second cylinder chambers which are hydraulically separated from each other and which are adapted to communicate with each other under the control of at least two alternative flow paths, which differ in hydraulic design so that they cause pressure changes on different pressure levels to be effected in the second cylinder chamber. A pressure detector detects the pressure of the fluid in the cylinder chambers and enables an alternative flow path in response to a rise of the pressure above a predetermined limit.

Abstract: A hydraulic element including a working cylinder defining a cylinder chamber having an axis and containing hydraulic medium, a working piston movable in the cylinder chamber along the axis and having an interior end arranged to communicate with the hydraulic medium in the cylinder chamber, and an annular piston movable in the cylinder chamber, along the axis, and enclosing the working piston, the annular piston having an interior end communicating with the hydraulic medium in the cylinder chamber so that movement of one of the pistons in a first direction along the axis causes the other of the pistons to move in a second direction opposite to the first direction.