In a fixture (1) by means of which a workpiece (2) to be machined is held on a tool table (3) of a machine tool (4), comprising: a housing (10) into which a passage opening (11) is worked, in which a clamping pin (12) is inserted for supporting the workpiece (2) on the housing (10) of the fixture (1), a fastening screw (14) engaging in the passage opening (11) by means of which the housing (10) is fixed onto the tool table (3) in an oriented position, a driving ring (15) mounted in the housing (10) in a rotating arrangement which is in a driving active connection with a driving spindle (20) inserted in the housing (10), by means of which the driving ring (15) can be moved about the longitudinal axis (11) of the passage opening (11) within a specified angle range (), and at least two locking pins (18) facing the longitudinal axis (11) of the passage opening (11), mounted in the housing (10) in such a way as to allow radial movement and each of which is in a driving connection with the driving ring (15), and by means of which the clamping pin (12) is locked in the passage opening (11) of the housing (10) in the clamped condition and/or is released in the initial condition, the conversion of the rotational movement of the driving ring (15) into a radial advance movement for the locking pins (18) used should take place without play and with at least two different ratios.

This is achieved in that a control surface (21) or control cam with at least two different pitches (22, 23) is worked onto the inside (16) of the driving ring (15) in each area of the locking pins (18), that an accommodating pocket (19) with a U-shaped cross section is worked into the corresponding locking pins (18) into which the driving ring (15) engages, and that a contact surface (25) is worked onto or provided on the wall of the locking pin (18) facing the inner wall (16) of the driving ring (15) and the contact surface (25) is in contact with the control surface (21) or control cam of the driving ring (15) and moves the corresponding locking pin (18) radially inwards or outwards depending on the direction of rotation of the driving ring (15).

An expanding locating pin assembly configured to locate and hold a part includes a housing, a locating pin, an actuating mechanism, and a controller. The housing is configured with a plurality of radial jaw guides and a part rest face. The locating pin has a plurality of jaws connected to and radially movable in the radial jaw guides and extending past the part rest face. The actuating mechanism synchronously moves the jaws to a radial position and applies a holding force to the part. The controller controls the radial position and the holding force of the jaws. The part rest face of the housing and the jaws of the locating pin are configured to receive the part in a located position. The jaws of the locating pin are configured to hold the part in the located position via the holding force and a friction force resulting from the holding force.

An expanding locating and clamping pin assembly configured to locate and clamp a part includes a housing, a locating pin, an actuating mechanism, and a controller. The housing is configured with a plurality of radial jaw guides and a part rest face. The locating pin has a plurality of jaws radially movable in the radial jaw guides, extending past the part rest face, and configured with a part clamping feature. The actuating mechanism is connected to the housing and the jaws and is configured to synchronously move the jaws to a radial position and to apply the clamping force. The controller controls the radial position of the jaws and the clamping force. The part rest face and the jaws of the locating pin are configured to receive the part in a located position and to clamp the part in the located position via the clamping force.

The invention related to a holding device (3), an arrangement and a method, the holding device (3) being designed to interlockingly receive and hold interchangeable ring (2) with holding cams (4) projecting radially outwards on the circumferential side, said holding device comprising a carrier ring (5) having a plurality of adjusting pins (7) which project in the axial direction and between which at least one insertion region (31) for receiving the interchangeable ring (2) is recessed, wherein a sleeve ring (6) positioned concentrically with respect to the carrier ring (5) is provided outside the carrier ring (5) and is rotatably and in particular interlockingly connected to the carrier ring (5), wherein the sleeve ring (6) has at least one radially inwardly protruding clamping jaw (8), wherein, in a first position of the sleeve ring (6) relative to the carrier ring (5), the clamping jaw (8) is positioned adjacent to the insertion ring (31) of the carrier ring (5) in the peripheral direction, and wherein in a second position of the sleeve ring (6) relative to the carrier ring (5), the clamping jaw (8) is positioned at least in part above the insertion region (31) of the carrier ring (5) in the peripheral direction.