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.

In a chuck (1) by means of which workpieces (2) are supported individually and centered for machining by a machine tool, the chuck comprising: a chuck body (3), four clamping jaws (5, 6, 7, 8) which are radially movably mounted on the chuck body (3) and are each arranged in pairs in an X or Y plane, and a drive piston (9) which is mounted in the chuck body (3) so as to be axially movable and which is drivably coupled to the four clamping jaws (5, 6, 7, 8) via a helical surface or helical gearing (10) worked on the drive piston (9) and the respective clamping jaws (5, 6, 7, 8), and feeds these synchronously in the direction of the workpiece (2) to be clamped or moves them away from the latter, a position-accurate, i.e. centered alignment for a large number of differently designed workpieces (2) can be achieved with a high repetition accuracy for subsequent clamping operations.

This is achieved in that a rocker (11) is provided between the drive piston (9) and two adjacent clamping jaws (5, 7 or 6, 8), the rocker (11) has a center of symmetry (12) into which a bolt (13) which is pivotably mounted on the drive piston (9) and about which the rocker (11) can be pivoted as a function of the contact of the clamping jaws (5, 6 or 7, 8) on the workpiece (2) is inserted, and a corresponding transmission pin (14, 15) is provided laterally adjacent to the bolt (13) and coupled drivably to the rocker (11), the respective clamping jaw (5, 6, 7, 10 or 8) being mounted and supported at the end of the transmission pin opposite the rocker (11).

A compensating chuck for concentrically clamping workpieces. The chuck has a drive unit having two pairs of entrainment members, wherein the entrainment members are preferably slidingly mounted, are respectively movable in paired relationship, and are so coupled to a respective one of the main jaws that a relative movement of a respective pair causes a synchronous movement of adjacent main jaws and that both a relative movement relative to each other with respectively different movement components and also a synchronous movement of the adjacent entrainment members in the same direction respectively causes a relative movement of adjacent main jaws.

A workholding apparatus (2) having jaws (5) comprising interchangeable adapter blocks (12) that enable a single workholding apparatus (2) to accommodate workpieces (22) having a range of inner bore diameters.

A compensation chuck for centrically clamping workpieces includes a housing, two pairs of mutually diametrally opposite base jaws for receiving corresponding clamping jaws, and a drive unit which is moveable preferably by power clamping having two pairs of drivable entrainment members. Two adjacent entrainment members are respectively coupled together by a first rocker and two further adjacent entrainment members are coupled together by a second rocker. There is also provided a coupling ring which guides a first entrainment member and a diametrally opposite second entrainment member in the peripheral direction tangentially relative to the clamping axis, such that a motion play is provided between the entrainment members and the coupling ring in the radial direction.

A compensation chuck for centrically clamping workpieces includes a housing, two pairs of mutually diametrally opposite base jaws for receiving corresponding clamping jaws, and a drive unit which is moveable preferably by power clamping having two pairs of drivable entrainment members. Two adjacent entrainment members are respectively coupled together by a first rocker and two further adjacent entrainment members are coupled together by a second rocker. There is also provided a coupling ring which guides a first entrainment member and a diametrally opposite second entrainment member in the peripheral direction tangentially relative to the clamping axis, such that a motion play is provided between the entrainment members and the coupling ring in the radial direction.

A chuck for gripping a workpiece includes: a chuck body; a jaw connected to the chuck body for constrained movement relative to the chuck body along a jaw path in jaw-closing and jaw-opening directions; an actuator body connected to the chuck body for constrained movement relative to the chuck body along an actuator path; and a slider body connected to the chuck body for constrained movement relative to the chuck body along a slider body path. The slider body is connected to the jaw for constrained movement relative to the jaw along a slider-body-to-jaw path. The slider body is connected to the actuator body for constrained movement relative to the actuator body along a slider-body-to-actuator-body path.

A clamping device for clamping a fastener, includes a clamping jaw, a first biasing member for biasing the clamping jaw, a clamping body having a central axis, a driving assembly for driving the clamping jaw to clamp the fastener, and a second member which can be driven by the first member to move axially relative to the clamping body so as to push the clamping jaw to clamp the fastener. The clamping body is formed with a notch for receiving the clamping jaw and the driving assembly is supported on the clamping body and includes a first member which can rotate and move axially relative to the clamping body. The installation structures between the clamping body, the driving assembly and the clamping jaw may be designed to be more compact so that the clamping device has a smaller size.

A device for transmitting a movement between a first member and a second member, namely from a driving member to a driven member, of the type having a cylindrical journal with a circular base mounted so as to rotate in a recess of the driven member or of the driving member. At least one of the ends of this journal is hollowed out by a groove capable of forming, on either side thereof, two shoes that are symmetrical with respect to an axial and diametral plane of the journal and capable of engaging, by a flattened surface, with the driving member or the driven member, the cross-section of each shoe being delimited by an arc of a circle matching the external surface of the journal, ending in a line segment that is part of the flattened surface.