Chuck arrangement (100) comprising at least three chuck jaws (110, 120, 130), each arranged to be radially displaceable into a respective clamping position in which it applies a radial clamping force (C) to a held workpiece (W). Each chuck jaw comprises fixing means. The chuck arrangement further comprises one respective counterweight (140, 150, 160) associated with each of said chuck jaw and mechanically connected to the chuck jaw in question so that the counterweight pulls the chuck jaw in a pull direction having a non-zero component radially towards a centre of rotation of the chuck arrangement as the chuck arrangement as it rotates. The invention is characterised in that each one of the said counterweights comprises at least one slot for a detachable weight. The invention also relates to a method.

A tool holder includes a tubular body having a shank on a first axial end portion, a tool gripping portion on a second axial end portion, and an elastic segment interposed between the shank and the tool gripping portion in the axial direction of the body. The elastic segment is more elastically deformable along the axial direction and around a circumferential direction of the tubular body than the shank and the tool gripping portion owing to a plurality of voids that extend through the elastic segment from an outer peripheral side of the tubular body to an inner peripheral side of the tubular body. Each of the voids includes segments that extend around the circumferential direction and along the axial direction of the tubular body.

A chuck grip accuracy checking method includes a gripping in which the measurement target is gripped on the claws, a moving step, and a measuring step. In the moving step, a movable member provided with a measurement instrument capable of measuring a run-out of the measurement target is moved by driving a movable-member driver to a position at which the measurement instrument can measure a run-out of the measurement target. In the measuring step, a run-out of the measurement target is measured by the measurement instrument, while the chuck is being rotated by driving a rotation driver.

A rim trimming machine comprises a mounting rack, a first axial moving device, a second axial moving device, a cutter turret, a base, and a chuck. The mounting rack is a board and is disposed vertically. The first axial moving device is mounted to the mounting rack and has a first axial sliding stand being movable along a first moving direction. The second axial moving device is mounted to the first axial sliding stand and has a second axial sliding stand being movable along a second moving direction. The cutter turret is mounted to the second axial moving device and has a cutter. The base is spaced apart from the mounting rack. The chuck is mounted on the base and has multiple jaws, each jaw having a radius. The cutter is above the chuck, and is aligned to a position between two ends of one of the jaws.

A projecting part 11A and a recessed part 12A which engage with each other are formed on a master jaw 11 and a top jaw 12. In the master jaw 11, a movable pin 20 movable in an axial direction and a shaft 30 movable in a radial direction is disposed, and the movable pin 20 is engaged with the shaft so that the movable pin 20 can be moved in the axial direction. The top jaw 12 is provided with a pin hole 12c into which the movable pin 20 can be inserted. The movable pin 20 is locked, by rotating the shaft 30 by a predetermined amount, at a first position in which the movable pin 20 is inserted in the pin hole 12c or at the second position in which the movable pin 20 is extracted from the pin hole 12c.

A workpiece adapter system to support a workpiece rotated by a rotary machine, the system including a first drive member having a proximal end configured to be secured in a chuck of a rotary machine, at least one workpiece adapter configured to secure at least a portion of an end of a workpiece in a central opening of the workpiece adapter, an adapter mount configured to be connected to the at least one workpiece adapter, and a universal joint assembly arranged between the first drive member and the adapter mount, the universal joint assembly comprising a first fork member coupled to the first drive member, and a second fork member coupled to the adapter mount. An adapter ring may be provided to rotatably support a workpiece being machined.

A power tool structure including a main body, a socket, a positioning ball, a pressing ring, a locking mechanism and a head is provided. The socket is connected to the main body and includes an arc space and a through hole passing through an annular wall of the socket to communicate with the arc space. The positioning ball is movably received in the through hole. The pressing ring includes a track. The locking mechanism sleeves on the pressing ring and is coupled to the pressing ring. The locking mechanism includes a coupling portion corresponding to the track, and the locking mechanism is forced to rotate so as to switch between a first position and a second position relative to the pressing ring, thereby allowing the locking mechanism to selectively press against the positioning ball. The head is pivotally inserted in the socket and includes a positioning portion.

The invention relates to a machine tool, in particular a lathe grinding machine, comprising a tool spindle having a collet and a spindle motor, wherein the collet has at least two clamping jaws which are actuatable for receiving and releasing a tool, and comprising an air channel which runs radially on the outside of the collet, wherein the air channel is configured as a sealing air channel (42) and forms a positive pressure chamber (44) at least partially above the clamping jaws (26).

The invention relates to a machine tool, in particular a lathe grinding machine, comprising a tool spindle having a collet and a spindle motor, wherein the collet has at least two clamping jaws which are actuatable for receiving and releasing a tool, and comprising an air channel which runs radially on the outside of the collet, wherein the air channel is configured as a sealing air channel (42) and forms a positive pressure chamber (44) at least partially above the clamping jaws (26).

A power and signal transmission device for a spindle of a machine tool is provided. The power and signal transmission device includes a spindle fixing portion, a shaft rotating portion, a power transmission component and a signal transmission component. The spindle fixing portion is provided with a power input end, a primary side power induction coil, a secondary side signal induction coil and at least one signal output end. The shaft rotating portion is provided with a joining end surface for bonding to a holder, a secondary side power induction coil and a primary side signal induction coil, and is rotatable with respect to the spindle fixing portion. The power transmission component transmits an electrical energy from the power input end. The signal transmission component transmits a holder signal to the signal output end. Each of the power and signal transmission components includes at least one elastic pogo pin.