A chuck includes a plurality of master jaws 20 that slide in the radial direction in the front surface of a body 10 in conjunction with slide of a plunger 40. The body 10 has a housing chamber 11 communicating with a plurality of keyways 13. The plunger 40 is fitted in the housing chamber 11. Each of the master jaws 20 includes a narrower part 21 and a wider part 22 fitted into an associated one of the keyways 13, and a wedge 23 connected to the plunger 40. The wider part 22 has a flat wider sliding surface 22b radially outside the wedge 23. Each of the keyways 13 has a wider slid surface 14.

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 chuck includes a plurality of master jaws 20 that slide in the radial direction in the front surface of a body 10 in conjunction with slide of a plunger 40. The body 10 has a housing chamber 11 communicating with a plurality of keyways 13. The plunger 40 is fitted in the housing chamber 11. Each of the master jaws 20 includes a narrower part 21 and a wider part 22 fitted into an associated one of the keyways 13, and a wedge 23 connected to the plunger 40. The wider part 22 has a flat wider sliding surface 22b radially outside the wedge 23. Each of the keyways 13 has a wider slid surface 14.

An inner circumferential surface of a chuck body (2) has three fitting recesses (22) curved as viewed from a rotational axis (C1). An outward elastic deformation that occurs, through gripping of a work (W1) with top jaws (5), at portions of a plunger (3) which correspond to slide holes (31a) causes the portions deformed by the elastic deformation to slide on the respective recessed portions (22) so that the plunger (3) is moved to cause a symmetry axis (Y1) of the slide hole (31a) to coincide with a symmetry axis (Y2) of a guide groove (25) of the chuck body (2).

The chuck mechanism includes: a chuck body 10; an axially movable plunger 40 disposed inside the chuck body; and a master jaw 20 radially movable by wedge action caused by fitting the plunger in the master jaw 20. A guide groove 11 that radially guides the master jaw and has a T-shaped cross section is formed in the chuck body. The master jaw has a narrow portion 23 and a wide portion 24 that form a T-shaped cross section. A wedge 21 fitted in a wedge groove 41 of the plunger is formed radially inside the wide portion. The end face 21a of the wedge in the width direction is positioned outward in the width direction with respect to the end face 23a of the narrow portion in the width direction.

The invention relates to an automation component or clamping device including a basic housing, at least one jaw movably guided in a jaw guide of the basic housing, and a piston movably guided in the basic housing, wherein the piston has a piston surface, wherein the piston is coupled in terms of movement to the jaw, and wherein a piston rod extending on the piston transversely with respect to the piston surface, wherein the centroid of the piston surface is spaced apart from the central longitudinal axis of the piston rod (22).

The disclosure provides a compact and low-cost gripper which allows an outside diameter of a piston to be increased. Provided is a gripper including a body case having, at one end, a cylinder part having a cylinder chamber which houses a piston so as to slide the piston along a central axis of the piston, and having, at the other end, a plurality of guide parts formed at regular intervals around the center axis and extending in a direction orthogonal to the center axis; a plurality of master jaws, on which top jaws can be removably mounted, guided by each of the guide parts; and a plunger having a plurality of interconnecting means which are respectively interconnected with each of the master jaws and slides along the central axis associated with a sliding operation of the piston.

A chuck mechanism of the present invention includes multiple master jaws placed movably in a radial direction on a front surface of a chuck body, and top jaws each detachably attached to front surfaces of the top jaws. Each master jaw and each top jaw have a raised portion and a recessed portion engageable with each other. Each of the raised and recessed portions has conical surfaces formed by part of a conical body. Each top jaw has a gripping surface formed by part of a circular columnar body. Upon work gripping, the center axes of the conical surfaces on a gripping side among the conical surfaces of each master jaw and each top jaw and the center axis of the gripping surface are all coincident with a rotation axis of the chuck body.

An inner circumferential surface of a chuck body (2) has three fitting recesses (22) curved as viewed from a rotational axis (C1). An outward elastic deformation that occurs, through gripping of a work (W1) with top jaws (5), at portions of a plunger (3) which correspond to slide holes (31a) causes the portions deformed by the elastic deformation to slide on the respective recessed portions (22) so that the plunger (3) is moved to cause a symmetry axis (Y1) of the slide hole (31a) to coincide with a symmetry axis (Y2) of a guide groove (25) of the chuck body (2).