In a clamping device (1) for the centred and repetitively accurate support of an object (2), in particular a workpiece to be machined on a machine tool, a tool or the like, the clamping device comprising: a chuck body (3) in which a receiving opening (4) is incorporated which has a longitudinal axis (5) as a centring reference for the object (2), a pulling element (6) which is mounted axially movably in the receiving opening (4), a collet chuck (7) which is inserted into the receiving opening (4) centred on the longitudinal axis (5) of the receiving opening (4) and which is driveably coupled to the pulling element (6), and a conical centring surface (8) which is worked onto the inner wall in the entrance area of the receiving opening (4),
it should be possible to insert a large number of objects (2) of different sizes into a receiving opening (4) of a chuck body (3) and locked in a centred position in this opening without the chuck bodies (3) or their receiving openings (4) having to be adapted to the differently sized collet chucks (7).

This is achieved in that an adapter sleeve (11) is provided, which is arranged between the receiving opening (4) of the chuck body (3) and the collet chuck (7) in the mounted condition, positionally oriented and centred on the conical centring surface (8), in that the outer contour of the adapter sleeve (11) is adapted to the inner contour of the receiving opening (4), in that the collet chuck (7) is mounted in the adapter sleeve (11) so as to be axially movable, and in that the inner contour of the adapter sleeve (11) has an inwardly inclined contact surface (12) which interacts with the outer contour of the collet chuck (7) in such a way that the inner diameter of the collet chuck (7) is reduced when the collet chuck (7) is drawn into the chuck body (3) by the pulling element (6), and the object (2) is thereby held centred and positionally oriented by the collet chuck (7).

A chuck mechanism operates a piston in a cylinder tube by using action of compressed air and opens and closes, by using a rod coupled to the piston, a pair of fingers, thereby gripping work W. The locking mechanism locks the fingers at work grip positions. The locking mechanism includes a first locking member, a second locking member, and a drive device. The first locking member is displaced when the pair of fingers are opened or closed. The second locking member retains the first locking member so as to lock the fingers at the work grip positions. The drive device relatively displaces the first locking member and the second locking member to locking positions and non-locking positions.

A counter bearing for machining spindles of machine tools has at least one expansion bushing with an elastically deformable wall that delimits at least one pressure chamber. The pressure chamber accommodates a pressure medium. A supply line for the pressure medium opens into the pressure chamber. A pressure conduit opens into the pressure chamber. A mechanically actuatable pressure element is disposed in the pressure conduit and actuated by an actuating tool. A piston is slidably arranged in the pressure conduit and actuated by the pressure element, wherein the piston loads the pressure medium.

A chuck mechanism operates a piston in a cylinder tube by using action of compressed air and opens and closes, by using a rod coupled to the piston, a pair of fingers, thereby gripping work W. The locking mechanism locks the fingers at work grip positions. The locking mechanism includes a first locking member, a second locking member, and a drive device. The first locking member is displaced when the pair of fingers are opened or closed. The second locking member retains the first locking member so as to lock the fingers at the work grip positions. The drive device relatively displaces the first locking member and the second locking member to locking positions and non-locking positions.

A machine tool includes: a hollow spindle including a hollow portion along an axial direction; a plurality of chuck claws openably mounted at a distal end portion of the hollow spindle, and configured to hold a workpiece; an operation rod inserted into the hollow portion of the hollow spindle in a movable manner, and configured to close the plurality of chuck claws with movement of the operation rod toward one side in the axial direction and open the plurality of chuck claws with movement of the operation rod toward the other side in the axial direction; and a measuring apparatus configured to measure an opening dimension of the plurality of chuck claws based on a movement amount of the operation rod.

A workpiece holding device includes: a chuck including a chuck body, and a plurality of chuck claws openably supported on the chuck body and configured to hold a workpiece; an operation rod configured to drive the plurality of chuck claws for opening and closing with movement of the operation rod; and a measuring apparatus configured to measure an opening dimension of the plurality of chuck claws based on a movement amount of the operation rod.

A hydraulic chuck device includes a cylinder portion operated by pressure oil, a chuck opened and closed by operation of the cylinder portion, a pressure oil supply controlling pressure of pressure oil supplied to the cylinder portion, and a chuck controller controlling the pressure oil supply. When controlling the pressure oil supply to cause a jaw portion to perform a clamping operation, during movement of the jaw portion from an unclamping position to a preliminary position situated before a clamping position, the chuck controller supplies pressure oil set at a first pressure into a cylinder chamber for clamping to move the jaw portion quickly, and during movement of the jaw portion from the preliminary position to the clamping positon, the chuck controller supplies pressure oil set at a second pressure lower than the first pressure into the cylinder chamber for clamping to move the jaw portion slowly.

A wheel fixture is disclosed. A main shaft drives a first positioning pull rod on a chuck body to extend and contract in the radial direction via a tightening screw, a clamping jaw is at a position within the travel range of extension and contraction, a wheel is positioned and clamped by the fixture, airtight support blocks are pressed down by the wheel and flush with the support plane of the clamping jaw, at this time, airtight ejector rods press second O rings to prevent air from flowing out of the airtight detection position, a detection system of a machine tool detects a preset air pressure value which indicate that the wheel has been placed correctly, and if the wheel is not placed correctly on the fixture, the machine tool will alarm through the detected pressure feedback.

A clamping jaw for a chuck includes a jaw body on which there is formed at least one jaw step having a step head, which has a sensor on its end face, for holding a clamping insert which is formed from a base leg and two fastening legs projecting from the base leg. On each of the opposite longitudinal sides of the step head there is formed a threaded bore for receiving a fastening screw whose screw head is received in a through-opening which is formed in the fastening leg of the clamping insert that is assigned to the longitudinal side, wherein, on each side, the longitudinal axes of the threaded bore and of the through-opening assigned thereto have an offset when the base leg bears against the end face. Also, a chuck has a chuck body, in which such clamping jaws are arranged in uniformly-distributed radial jaw guides.

In a clamping device (1) for machine tools (2) that is equipped with a power-operated chuck (5) and an electric drive motor (11) with a changeover function for triggering clamping movements, a motion converter (31) as well as a force accumulator (51) for maintaining the clamping force, which comprises several spring packs (52) supported on an adjustment element (32) of the motion converter (31), the spring packs (52) are each only arranged on one side of the adjustment element (32). In addition, a pressure piece (53) interacting with the adjustment element (32) is firmly connected to several spacer elements (57), each of which carries a stop disc (61) and passes through the spring packs (52) as well as a spacer (66). The spacer elements (57) and the spacers (66) can be adjusted relative to one another and the spacers (66) interact with spacer pins (71) which are guided through the pressure piece (53) and are supported on the wall (24) of the housing (21) opposite to the spring packs (52). Due to this embodiment, the spring packs (52) are always preloaded and do not have any axial play, and the adjustment movements of the pressure piece can thus be registered and evaluated directly. Rather, the spring packs (52) have a defined preload at all times, with the effect that the operating method is improved compared to embodiments of prior art.