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 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 provided 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 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.

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 chuck (10) includes a jaw guide (64), interleaving jaws (66), and an inclined engagement surface (84). The jaw guide defines a longitudinal axis (24) and includes jaw channels (65) circumferentially distributed about the axis. The jaws are slidably disposed in the jaw channels Each jaw has a clamping surface (88) facing the axis and a driving surface (90) substantially opposite the clamping surface and a protrusion (92) on a first lateral side and a cavity (96) on a second lateral side. The protrusion of each jaw is disposed at least in part in the cavity of an adjacent jaw. The engagement surface is on one of an inner surface of the jaw guide and an engagement sleeve (80), and is substantially centered about the axis and substantially parallel to the driving surface. Displacement of the jaws relative to the engagement surface in a clamping direction displaces the clamping surfaces toward the axis.

A chuck for clamping a shaft. The chuck includes a jaw guide defining an axis and including jaw channels circumferentially distributed about the axis. Interleaving jaws are slidably disposed in the jaw channels and each jaw has a clamping surface facing the axis and a driving surface opposite the clamping surface and a protrusion on one side and a cavity on another side with the protrusion of each jaw disposed at least partially in the cavity of an adjacent jaw. A spring having a base and fingers extending from the base are engageable with the jaws to retain the jaws in the jaw channels. An inclined engagement surface is included on an inner surface of the jaw guide or an engagement sleeve. Displacement of the jaws relative to the inclined engagement surface in a clamping direction displaces the clamping surfaces toward the axis.