Various implementations include a surgical screwdriver that comprises a first rotating shaft configured to be rotated about a respective longitudinal axis, a second rotating shaft extending along a respective development axis transverse to the longitudinal axis of the first shaft and having a shaped end tip that can be inserted into the head of a screw, and a transmission member interposed between respective first ends of the shafts to transfer the rotation from the first shaft to the second shaft. The transmission member comprises a pair of hemispherical elements, hinged together about a respective junction axis that is perpendicular to the longitudinal axis of the first shaft, and each hemispherical element is in turn hinged to a first end of one of said shafts.

A universal joint includes a socket member and a driving member. The socket member includes a receiving hole, and an inner periphery of the receiving hole is formed with first evading portions and first abutting portions staggered with each other to cause the first abutting portions not connected to each other. Each first abutting portion is provided with a first abutting face, a second abutting face, and an adjacent edge formed between the first abutting face and the second abutting face. One side of the adjacent edge forms an adjacent edge angle being greater than 177 degrees and less than 180 degrees. The driving member includes a rounded base arranged in the receiving hole and a driving column opposite to the rounded base.

A fixation structure of a sleeve tool is provided and includes a universal joint and a universal socket. The universal joint has a surface and a universal joint hole thereunder. The universal joint hole holds therein a spring and a ball. The universal joint has a radial length including a distance by which the ball protrudes from the surface. The universal socket has a connection hole for receiving and engaging with the universal joint and has an inner side. A recess is disposed under the inner side of the universal socket. The connection hole has a hole diameter. The ratio of the radial length to the hole diameter is greater than 0.902 to prevent the ball from retracting completely into the recess even when a user pulls the universal joint 20 by hand, thereby preventing the universal joint from escaping from the connection hole of the universal socket.

An elastic short-pin type universal joint includes a first base, a second base, a jointer, a first elastic member, two second elastic members, and four short pins. The first base engages the second base to form a space therebetween. The jointer is received in the space between the first and the second bases. The jointer has a first bore passing through the jointer, a second bore, and a third bore. The first elastic member is received in the first bore of the jointer, and the second elastic members are received in the second bore and the third bore. The short pins are urged by ends of the first elastic member and the second elastic members to press the first base and the second base respectively. As a result, the first base is able to rotate related to the second base in all directions.

A driving tool with universal rotating structure includes a first drive joint member and a second drive joint member. The first drive joint member defines a compartment and at least one slot. The first end of the at least one slot includes is in communication with the compartment. The at least one slot extends through an outer periphery of the first drive joint member. The at least one slot includes a retaining member movably disposed therein. The outer periphery of the first drive joint member includes an enclosing ring disposed thereon. The enclosing ring is elastic and includes an inner periphery abutting against a side of the retaining member. The second drive joint member includes a head rotatably coupled to the first drive joint member. The head is disposed in the compartment. The head extends from a first end to a second end concavely along a second axis.

A universal joint includes a first joining structure and a second joining structure movably coupled to each other. The first and the second joining structures are movable relative to each other to an aligned position and an inclined position. The first and the second joining structures include a resilient member disposed therebetween. The resilient member has a first end retained on the first joining structure and a second end retained on the second joining structure.

An elastic short-pin type universal joint includes a first base, a second base, a jointer, a first elastic member, two second elastic members, and four short pins. The first base engages the second base to form a space therebetween. The jointer is received in the space between the first and the second bases. The jointer has a first bore passing through the jointer, a second bore, and a third bore. The first elastic member is received in the first bore of the jointer, and the second elastic members are received in the second bore and the third bore. The short pins are urged by ends of the first elastic member and the second elastic members to press the first base and the second base respectively. As a result, the first base is able to rotate related to the second base in all directions.

A two-stage universal joint includes a sleeve member, a driving member, and an elastic member. The sleeve member defines an axial direction and has a sleeve portion and a connection portion. The sleeve portion has a receiving groove having plural positioning protrusions extending axially on an inner wall thereof. One of the positioning protrusions has a recessed portion. The driving portion has a polygonal ball-joint having plural arc-face sections. The polygonal ball-joint is inserted into the receiving groove. The driving member is slidable with respect to the sleeve member between a first position and a second position. The polygonal ball-joint has a biasing member tending to move outward.

An electric torque wrench capable of sensing a manual operating torque includes: an outer housing having an accommodating space at an internal thereof, a motor and a reduction device arranged therein; the reduction device having a reduction gear assembly with a hollow ring gear member; a front end of the ring gear member having at least one extension arm and at least one sensing plane formed thereon; a torque sensing unit arranged on the sensing plane; a driving device installed at the front end of the outer housing and having a working head arranged at the front end thereof; the extension arm of the ring gear member secured and attached onto the driving device. With the torque sensing unit installed on the extension arm, the electric torque wrench can be rotated manually with hand and is able to measure the torque value.

A quick release device of a hand tool includes: a main body; an operating portion, including a slidable sleeve movably disposed around the main body and a pin radially inserted into the slidable sleeve, the operating portion further including a movable rod movably disposed in the main body, the pin connected with the movable rod; an annular plastic body, rotatably disposed around the slidable sleeve and corresponding to the pin, a stepped structure formed between the slidable sleeve and the annular plastic body; an identification portion, disposed around the annular plastic body; wherein the slidable sleeve is movable between first and second positions, when the slidable sleeve moves toward the first position, the pin drives the movable rod to move toward a fixing position; when the slidable sleeve moves toward the second position, the pin pushes the movable rod to move toward a releasing position.