According to one embodiment, a sensor attachment/detachment device of the embodiment includes a sensor, a bonding member, a support portion, and a release execution portion. The bonding member is bonded to a first surface of the sensor and has a function of decreasing an adhesive force. The support portion can support the sensor by directly contacting a second surface of the sensor or via another functional portion. The release execution portion performs a process of releasing the bonding member from the object by decreasing the adhesive force of the bonding member after the sensor is attached to the object by the bonding member.

A machine tool includes a plurality of modules, and a control means for controlling operation of the modules, wherein the plurality of modules include a fixed module and two movable modules. The control means includes a restriction means for restricting the movement of the two movable modules for allowing only one of the movable modules to be moved to a facing position facing the fixed module; and a determination means for determining the movable module to be moved to the facing position. The control means is configured to control the operation of the plurality of modules so that, when the operation under cooperation of the fixed module and one of the movable modules has been completed, the restriction means releases the restriction of the movement of the other movable module to the facing position.

A machine tool includes a plurality of modules, and a control means for controlling operation of the modules, wherein the plurality of modules include a fixed module and two movable modules. The control means includes a restriction means for restricting the movement of the two movable modules for allowing only one of the movable modules to be moved to a facing position facing the fixed module; and a determination means for determining the movable module to be moved to the facing position. The control means is configured to control the operation of the plurality of modules so that, when the operation under cooperation of the fixed module and one of the movable modules has been completed, the restriction means releases the restriction of the movement of the other movable module to the facing position.

A machine tool improving measurement accuracy of a machined workpiece diameter. A machine tool comprises a displacement sensor mounted on at least one of a guide bush and a spindle supporting unit. The machine tool further comprises a calculating unit which calculates a diameter of the machined workpiece based on a measurement value of the machined workpiece by the displacement sensor. The spindle is movable back and forth in an axial direction. The spindle is retracted after machining to bring a machined portion of the workpiece to a predetermined measurement position in the axial direction to allow the displacement sensor to measure the machined portion.

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, 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 machine tool improving measurement accuracy of a machined workpiece diameter. A machine tool comprises a displacement sensor mounted on at least one of a guide bush and a spindle supporting unit. The machine tool further comprises a calculating unit which calculates a diameter of the machined workpiece based on a measurement value of the machined workpiece by the displacement sensor. The spindle is movable back and forth in an axial direction. The spindle is retracted after machining to bring a machined portion of the workpiece to a predetermined measurement position in the axial direction to allow the displacement sensor to measure the machined portion.

A lathe capable of shortening a spindle with respect to a spindle axis direction. A spindle provided with a chuck at the front end thereof is rotatably supported on a support by bearings. A chuck operating apparatus includes a tilt claw and a shifter. A built-in motor is disposed between the bearings to rotate the spindle. The claw is provide outside the spindle and between the bearings. The claw has a movable end whose distance from the spindle axis varies between a first posture to bring the chuck into the opened state and a second posture to bring the chuck into the closed state. The shifter is provided outside the claw and movable in the spindle axis direction to be brought in a first position to bring the claw into the first posture and in a second position to bring the claw into the second posture.

A chuck operating apparatus includes a claw, a shifter, and a shifter drive unit. The rotatable claw has a first posture to bring the chuck into the opened state and a second posture to bring the chuck into the closed state. The rotatable shifter is brought in a first position to bring the claw into the first posture and in a second position to bring the claw into the second posture. The shifter drive unit has a shifter lever having an insertion part provided with a shifter bearing capable of being brought into contact with a side surface of an outward groove of the shifter. A roller is provided on one of the claw and the shifter in a contact position with the other to roll in a spindle axis direction and a groove is formed on the other to receive the roller when the chuck is in the opened state.

A lathe capable of facilitating maintenance of a chucking mechanism. A chuck operating apparatus includes a claw and a shifter to open and close a chuck provided on a spindle. The tilt claw provided outside the spindle has a first posture to bring the chuck into the opened state and a second posture to bring the chuck into the closed state. The shifter provided outside the spindle and movable in a spindle axis direction is brought in a first position to bring the claw into the first posture and in a second position to bring the claw into the second posture. A roller is mounted on the shifter in a contact position with the claw to roll in the spindle axis direction.