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.

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 chuck (1) is provided by means of which workpieces (2) are supported individually for machining by a machine tool (3) and aligned coaxially to a centering axis (4), which serves as a reference for machining the workpiece (2) by the machine tool (3), having a chuck body (5), having at least four clamping jaws (6, 7, 8, 9) that are radially movably mounted on the chuck body (5) and are arranged in pairs in an X or Y plane and by means of which the workpiece (2) is held during the machining process to be aligned with respect to the centering axis (4), and having a pull piston (45) that is mounted in or at the chuck body (5) so as to be linearly movable and which is drivably coupled to a respective clamping jaw (6, 7, 8, 9) such that during the linear movement of the pull piston (45) the clamping jaws (6, 7, 8, 9) are radially fed in the direction of the workpiece (2) to be clamped or moved away from same in a synchronous manner, wherein the pull piston (45) is arranged coaxially with respect to the centering axis (4) inside the chuck body (5) and is axially actuated by one or more drive means (12, 13, 52, 53), on the one hand aiming at adjusting the compensatory movements between two adjacent clamping jaws running perpendicular to one another (6, 7, 8, 9) irrespective of their feed movement and operative contact with the workpiece (2) to be clamped, and on the other hand aiming at the constructional height of such chuck (1) being as small as possible. This aim is achieved in that each drive means (12, 13, 52, 53) has a linearly movable piston rod (26) or threaded spindle (55), whose respective longitudinal axis (26′ or 55′) is arranged to be perpendicular to the centering axis (4). (FIG. 1)

The invention relates to a chuck (1) via which workpieces (2) are supported on a machine tool in a separate and centered manner for machining by the machine tool, including a chuck body (3) and at least four radially oriented guide grooves (4) that are incorporated into same, including at least four clamping jaws (5, 6, 7, 8) that are situated in each case in pairs in an x or y plane, and separately inserted into one of the guide grooves (4) in a movably supported manner, including a drive element (9) that is mounted in the chuck body (3), and which synchronously feeds the four clamping jaws (5, 6, 7, 8) in the direction of the workpiece (2) to be clamped or is moved away by same, and including a rocker (11) that is provided in each case between the drive element (9) and two adjacent clamping jaws (5, 7 or 6, 8), the rocker having a center of symmetry (12) into which a bolt (13) that is swivelably mounted on the drive element (9) is inserted, the rocker (11) being swivelable about the bolt as a function of the contact of the clamping jaws (5, 6 or 7, 8) with the workpiece (2). According to the invention, movement compensation is to take place between two adjacent clamping jaws (5, 6, 7, 8), via which the various clamping jaws (5, 6, 7, 8) are quickly exchangeable without uninstalling the chuck body (3). This is achieved by providing a wedge rod (31) and/or a drive ring, which in each case are/is drivingly coupled to the drive element (9) and one of the clamping jaws (5, 6, 7, 8), between the drive element (9) and one of the chuck jaws (5, 6, 7, 8).

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 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 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.

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).