A surgical tool-piece and a coupling mechanism for a surgical tool-piece are provided. The surgical tool-piece is configured to be driving by a driving mechanism. The surgical tool-piece comprises a shaft having a longitudinal axis running from a distal end of the shaft to a coupling portion at a proximal end of the shaft. The coupling portion comprises a driving section comprising at least three indentations located around the circumference of the coupling portion, each indentation being configured to receive a corresponding driving element of the driving mechanism to secure the tool-piece both longitudinally and rotationally.

A surgical tool-piece and a coupling mechanism for a surgical tool-piece are provided. The surgical tool-piece is configured to be driving by a driving mechanism. The surgical tool-piece comprises a shaft having a longitudinal axis running from a distal end of the shaft to a coupling portion at a proximal end of the shaft. The coupling portion comprises a driving section comprising at least three indentations located around the circumference of the coupling portion, each indentation being configured to receive a corresponding driving element of the driving mechanism to secure the tool-piece both longitudinally and rotationally.

Disclosed is a built-in type electric driving system of a machine tool. The system is capable of directly connecting a motor, which drives a spindle in a lathe which processes a workpiece, to an outer surface of the spindle without using a belt to rotate the spindle, and is capable of selectively transferring the power of the motor to a rotation system including a drawbar and a spindle for driving a chuck using a clutch device.

Two balls can reliably retract for smooth insertion of a tip tool into a tool holder. A hammer drill includes a tool holder, two balls in reception holes in the tool holder, a guide washer urging the balls forward in the reception holes with a coil spring, a pressure ring adjacent to a front of the guide washer, and an operation sleeve allowing the pressure ring to move backward and forward between locked and unlocked positions of the two balls. The guide washer includes, on its front surface, a projection toward the pressure ring to cause, with the pressure ring at the locked position, the guide washer to be inclined with respect to an axis of the tool holder for a first ball to move more backward than a second ball.

The tool connector includes a socket having a receiving space and a through hole communicating the receiving space, a sliding member slidably received in the receiving space, a positioning member received in the receiving space, and a hook member. A funnel-shaped opening is formed at an end of the receiving space. The sliding member is connected to the socket with an end via a first elastic member, and the other end is for a tool bit to abut against. The positioning member is selectively inserted into the through hole. An end of the hook member is connected to the sliding member, and the other end has a hook portion for grasp the tool bit. When the positioning member is moved inward and the sliding member is moved toward the funnel-shaped opening, the hook portion is swingable in the funnel-shaped opening to release the tool bit.

An extension assembly configured to permit a user to drill a hole through inaccessible areas in a wall is disclosed. The extension assembly includes a flexible, solid core rod having first and second ends and a holding means. The rod is configured to extend through a hole in a wall cavity and flex therein to position a tool bit at an inaccessible location in the wall cavity and permit a user to drill a hole through a substrate at the inaccessible location. The holding means is secured to the second end of the rod for releasably holding a tool bit for rotation with the rod and includes a sleeve adapted to slide axially along a body of the holding means between a secured position where a tool bit is securely held within the holding means and a release position where the tool bit is released from the holding means.

To reduce size increase, an impact tool includes a motor, a spindle located frontward from the motor, rotatable by the motor, and having a support hole extending rearward from a front end of the spindle, a hammer supported by the spindle, a ball between the spindle and the hammer, and an anvil received in the support hole and strikable by the hammer in a rotation direction. The anvil has a rear end located rearward from the ball.

To reduce size increase, an impact tool includes a motor, a spindle located frontward from the motor, rotatable by the motor, and having a support hole extending rearward from a front end of the spindle, a hammer supported by the spindle, a ball between the spindle and the hammer, and an anvil received in the support hole and strikable by the hammer in a rotation direction. The anvil has a rear end located rearward from the ball.

A quick-release device for screwdriver bit includes a shank having a polygonal hole longitudinally defined in one end thereof and adapted for partially receiving a bit. At least one slot is longitudinally defined in the shank. An annular groove is defined in an inner periphery of the polygonal hole and communicates with the at least one slot, wherein the annular groove is formed with a tapered section toward the first end of the shank. An expandable limit element is received in the annular groove. A sleeve is movably sleeved on the shank. The sleeve has at least one protrusion inwardly extending therefrom and engaged into the at least one slot and abutting against the limit element when removing the bit form the polygonal hole. A stopper is secured on one end of the shank for preventing the sleeve from removing from the shank.

A hand tool has a tool shaft, an inner sliding sleeve, an engagement module, and an outer sliding sleeve. The inner sliding sleeve is mounted around the tool shaft, is selectively engaged with the tool shaft, and has a connection hole and two slits. The connection hole is rectangular in section to define two long sides each having a middle and two short sides. The two slits are defined respectively and longitudinally in the middles of the long sides of the connection hole. The engagement module has a spring mounted around the inner sliding sleeve. The outer sliding sleeve is mounted around the inner sliding sleeve, abuts the spring, and is selectively engaged with the inner sliding sleeve. The hand tool is applied for connecting with an inner polygonal bolt or an outer polygonal bolt.