Quick-acting clamping devices

摘要

A quick-acting clamping device for clamping tools or workpieces in machine tools comprises a piston which is slidable transversely to the clamping direction and which acts on a toggle mechanism which in turn moves a clamping piece. A pressure plate upon which the toggle mechanism acts is displaceable in the clamping direction in a housing which contains the transverse piston. The fluid under pressure which acts on the transverse piston to activate the toggle mechanism also acts directly on the pressure plate to assist in clamping. Because of the assisting force produced by the pressure plate it is possible for the transverse piston to move the members of the toggle mechanism from starting positions in which they lie at large angles to the clamping direction, that is with a big angular displacement from their dead-center position, in which they initially exert only a small force on the clamping piece. Because of this large angular displacement of the members of the toggle mechanism, the toggle mechanism by itself can produce a large linear movement of the clamping piece.