Abstract: A hydraulic drawing cushion (17) for a drawing press (10) includes at least one hydraulic cylinder (21) comprising a piston rod (27) that causes a total force (G) to act on the metal sheet holding ring (20). The hydraulic cylinder (21) comprises a hydraulic work circuit (37) to generate a hydraulic work force (A) in a work direction (Z) to act on a ring part (28) to which a force can be applied on both sides. Independently, a spring force (F) acts on the piston (26). The spring force (F) is neither controlled nor adjusted, but is preset. Preferably, the spring force (F) is exclusively a function of the position or location of the piston (26) relative to the cylinder housing (25). The total force (G) acting on the piston (26) results from the addition of the vectors of the work force (A) and the spring force (F).

Abstract: A method for controlling a press having an electric drive motor and a press transmission with a variable gear ratio (Ü) is disclosed. A tappet is movably mounted in a stroke direction (R) and is connected to the electric drive motor via the press transmission. The gear ratio (Ü) continuously increases as the tappet moves from an upper reversal point (OT) to a lower reversal point (UT). To prevent the press from exceeding a specified maximum pressing force (Fmax), a position-dependent maximum torque (Mmax) is specified for the motor. The control device compares each applied drive torque (M) with the maximum torque (Mmax). If the drive torque (M) exceeds the maximum torque (Mmax), the danger of the force applied by the tappet exceeding the maximum pressing force (Fmax) during an ongoing forming movement is detected. The control device then reduces the drive torque (M) to prevent damage to the press.

Abstract: A hydraulic drawing cushion (17) for a drawing press (10) includes at least one hydraulic cylinder (21) comprising a piston rod (27) that causes a total force (G) to act on the metal sheet holding ring (20). The hydraulic cylinder (21) comprises a hydraulic work circuit (37) to generate a hydraulic work force (A) in a work direction (Z) to act on a ring part (28) to which a force can be applied on both sides. Independently, a spring force (F) acts on the piston (26). The spring force (F) is neither controlled nor adjusted, but is preset. Preferably, the spring force (F) is exclusively a function of the position or location of the piston (26) relative to the cylinder housing (25). The total force (G) acting on the piston (26) results from the addition of the vectors of the work force (A) and the spring force (F).