Abstract: A device for holding workpieces in a releasable manner is proposed, comprising a mounting plate (2) with a clamping pin (3) for mounting a workpiece and an end plate (5) for connecting in a supporting manner to a machining apparatus for machining the workpiece, a hydraulically or pneumatically movable piston (11), a ball sleeve (15) with balls (16), which are arranged in such a way that they can be moved with respect to the clamping pin into the ball sleeve by the piston, and at least one spring (19) acting against the clamping force being provided between the mounting plate and the end plate as means which transmit the clamping force, and the mounting plate (2) having a centring region (21) which interacts with the clamping pin (3) and is designed in one piece and in an annular-disc shape.

Abstract: A coupling assembly for a machining tool is proposed that serves for mounting a work piece in a torsionally fixed manner. The work piece is received on a pallet that is located on a pallet support member. The pallet and the pallet support member are provided with cooperating means for exactly positioning the pallet on the pallet support member in the horizontal as well in the vertical plane.