A rotational force transmission mechanism includes a shaft and an engagement member. The shaft is rotatable about a first axis. The shaft includes a leading end portion having a second groove and a first groove which is configured to receive a rotatable portion of a tool holder so that the shaft rotates the rotatable portion about the first axis. The engagement member is movable along the first axis between a first position and a second position and rotatable about the first axis together with the shaft. The engagement member includes an engagement portion configured to be received in the second groove. At least one of the shaft and the engagement member has an inclined surface that moves the engagement portion in a direction toward the first axis when the engagement member moves from the first position to the second position.

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 method comprises the steps of providing a tool over a collar secured to a stud on a gas turbine engine system. The collet is driven to rotate and remove the collar from the stud. A tool for removing collars from studs has a driver with a housing receiving a piston. A spring drives the piston, and the housing also has a hydraulic fluid supply opening for selectively receiving a hydraulic fluid to move the piston in opposition to a force from the spring. Collet fingers are movable between a released position and a secured position when a supply of hydraulic fluid is supplied into the housing.

A method comprises the steps of providing a tool over a collar secured to a stud on a gas turbine engine system. The collet is driven to rotate and remove the collar from the stud. A tool for removing collars from studs has a driver with a housing receiving a piston. A spring drives the piston, and the housing also has a hydraulic fluid supply opening for selectively receiving a hydraulic fluid to move the piston in opposition to a force from the spring. Collet fingers are movable between a released position and a secured position when a supply of hydraulic fluid is supplied into the housing.

A gripping device (100) for holding, centring and/or clamping a micromechanical or horological component (200) in a chamber delimited by a collet including at least one movable jaw (2) and at least one stationary jaw (3), wherein some of the movable jaws (2) and/or stationary jaws (3) include a reference surface (20) to support a component (200) bearing frontally thereagainst, and the gripping device (100) includes both, on the one hand, stationary jaws (3) including the reference surface (20) to support the component (200) bearing thereagainst, and movable jaws (2) for centring and/or clamping the component (200), and on the other hand a vacuum generator (60) for creating the vacuum in the clamping chamber. Also a related method.

A clamping device (100) includes a first movable member (210) that is movable along an extending direction of a first body interior space (120), a disc spring (260), an annular spring (270), a spring (280) and a collet (300). A driving mechanism (400) has a second movable member (430) that moves along an extending direction of a second body interior space (130) with rotation of a rotary member (410). When the rotary member is rotated in one direction, the first movable member moves toward an oil-filled closed space (121) and the clamping device is set to a clamping mode that will hold a tool holder (510). On the other hand, when the rotary member is rotated in the opposite direction, the first movable member moves towards the side opposite of the oil-filled closed space and the clamping device is set to an unclamping mode that will release the tool holder.

A spindle apparatus for use at a machine tool, having: an assembly including a workpiece spindle to receive an elongated workpiece and a motor for driving spindle rotation of the workpiece spindle about a spindle axis; a rotary guide-bush assembly being axially arranged with the workpiece spindle with respect to the spindle axis, the rotary guide-bush assembly receiving the elongated workpiece supported at the rotary guide-bush assembly to rotate about the spindle axis enabling movement of the elongated workpiece; wherein the rotary guide-bush assembly includes a portion to clamp the elongated workpiece, received in the rotary guide-bush and in the workpiece spindle, to transfer driving torque applied from the spindle motor during a driven acceleration of the rotation through the clamped elongated workpiece for rotation of the rotary guide-bush synchronized with the driven acceleration of the rotation of the workpiece spindle.

A spindle apparatus for use at a machine tool, in particular a lathe, has: a spindle assembly including a workpiece spindle to receive an elongated workpiece and a spindle motor for driving spindle rotation; and a rotary guide-bush assembly axially arranged with the workpiece spindle, the rotary guide-bush assembly including a rotary guide-bush to receive the elongated workpiece and supported at the rotary guide-bush assembly to rotate with the elongated workpiece received in the workpiece spindle about the axis while enabling a movement of the elongated workpiece in the axial direction. The spindle and rotary guide-bush assemblies connect to each other by a torque transferring connection, between the spindle and rotary guide-bush assemblies along the axis to transfer driving torque during acceleration or deceleration of the spindle rotation driven by the spindle motor to the rotary guide-bush of the rotary guide-bush assembly.

A clamping device for clamping a workpiece to a machine spindle includes at least one clamping bush which extends around a central axis and has at least one clamping surface for the workpiece and at least one clamping body. The clamping bush on a side remote from the clamping surface at least one support surface which extends about the central axis along a helical line. On a side facing, the clamping bush comprises at least one support surface which extends about the central axis along a helical line with a predefined pitch and is inclined at an angle of inclination to a direction axial to the central axis. The clamping body includes a hydraulic chamber in the interior of the clamping body. The clamping device also includes a displacement element, and at least one pressure generator. A clamping force is generatable between the clamping bush and workpiece.

This invention provides a machine tool capable of easily and quickly attaching/detaching a tool holder while reliably holding the tool holder, including at least two clamp holes (211) that receive pins (203) extending through at least two through holes (202) provided in a tool holder (134), at least two tubular clamp sleeves (302) fitted in the at least two clamp holes (211), respectively, and each including a flexible trunk portion (321), a fluid encapsulating chamber that encapsulates a fluid, a channel extended from the fluid encapsulating chamber to an outer peripheral surface of the flexible trunk portion, and a pressure adjusting portion that adjusts a pressure of the fluid in the fluid encapsulating chamber, wherein a clamp fastening force is made to act on the pins (203) in synchronism with an increase or a decrease in the fluid pressure in the fluid encapsulating chamber.