Clamping device

A clamping device, especially for machine tools, that are for example equipped with a power-operated chuck for holding a workpiece and the clamping jaws of which can be adjusted using the clamping device by means of an axially moveable draw rod as the actuating element, in which the clamping device, arranged in a housing, possesses an electric drive motor with a changeover function for triggering clamping movements, a motion converter for converting the adjustment movements of the rotor shaft of the drive motor into the axial adjustment movements of the draw rod required for actuating the clamping jaws as well as a force accumulator for maintaining the clamping force, which comprises several pre-stressed spring packs supported on an adjustment element of the motion converter that is configured as a hollow shaft and is provided with a projection projecting radially outward,

• characterised in that
• when spring packs are arranged on both sides of the adjustment element of the motion converter, each of the spring packs is inserted between a pressure piece and stop discs in a mirror-image arrangement, that the stop discs are held by spacer elements attached to the pressure piece in such a way as to allow for limited movement and that stops are arranged on the stop discs on the housing and the pressure piece;
• and
• wherein the pressure piece, the spacer elements with stop discs and springs as well as the spacer and the spacer pins inserted in the pressure piece or the pressure piece and the spacer elements with stop discs and springs form a structural unit B that can be preassembled and clamped into the housing without play.

A clamping device, especially for machine tools, that are, for example, equipped with a power-operated chuck for holding a workpiece and the clamping jaws of which can be adjusted using the clamping device by means of an axially moveable draw rod as the actuating element, in which the clamping device, arranged in a housing, possesses an electric drive motor with a changeover function for triggering clamping movements, a motion converter for converting the adjustment movements of the rotor shaft of the drive motor into the axial adjustment movements of the draw rod required for actuating the clamping jaws as well as a force accumulator for maintaining the clamping force, which comprises several pre-stressed spring packs arranged around the circumference supported on an adjustment element of the motion converter that is configured as a hollow shaft and is provided with a projection projecting radially outward,

• characterised in that,
• for internal and external clamping of a workpiece, each of the spring packs of the force accumulator is inserted on one side of the adjustment element of the motion converter between the housing and a pressure piece,
• wherein the pressure piece is supported on a shoulder formed on the adjustment element, with the effect that adjustment movements of the adjustment element are transmitted directly to the pressure piece, that several spacer elements are firmly connected to the pressure piece, each of which carries a stop disc and passes through the spring packs as well as a spacer, that the spacer elements and the spacer can be adjusted relative to one another and that the spacer interacts with spacer pins in an axial direction, in which case these spacer pins pass through the pressure piece and are supported against the wall of the housing opposite to the spring packs.