An anti-disengagement structure of a tool head for insertion into an insertion recess of a fastener is provided. Abutting faces extend from a periphery of an end face of a working portion. At least one abutting face is partly formed with a groove filled with an elastic member which is partly protrusive out of the groove and beyond the surface of the abutting face. The largest extent between the protruded-out part of the elastic member and the abutting face of another elastic member is larger then the largest inner extent of the insertion recess. Thereby, with the stretchable characteristic of the elastic member, the fastener can be smoothly inserted into the insertion recess and abutted against an inner surface of the insertion recess to achieve anti-disengagement effect.

A screwdriver with rotating lever according to this invention includes a screwdriver head. The screwdriver head includes a rod, an operation portion formed at a first end of the rod, and a fixing portion formed at a second end of the rod. The rod is a polygonal prism and extends spirally from the operation portion to the fixing portion to form a spiral curved surface. With the rod formed with the spiral curved surface, when the screwdriver with rotating lever operates, the rod is of higher strength and may bear stronger torsion stress for increasing the service life of the screwdriver.

A multi-purpose tool assembly may comprise one or more body members. A body member may comprise a magnet, a main body and a bit. The main body may comprise various sides, one or more of which may include one or more apertures on its surface and one or more bits protruding therefrom. The bit may include a bit body and a bit head. The body members may include differently configured bits. Bits may be inserted into the apertures to connect the body members. The bit assembly may comprise one or more attachment members. An attachment member may attach two or more bits together.

An accessory tool includes an adapter end, and a shank coupled to the adapter end and including a first length. The shank includes a tool engagement portion, and a first reduced portion disposed between the tool engagement portion and the adapter end. The first reduced portion has a second length. The shank additionally includes a second reduced portion formed in the tool engagement portion between the first reduced portion and an end of the shank. The second length is 2.5% to 15% of a total length of the accessory tool.

A driving tool includes a body portion, a driving portion, and a neck portion, wherein the driving portion defines a reference rotating axis, wherein distal end of the driving portion opposite to the body portion is provided with a front driving face having a first width in a radial direction of the reference rotating axis, wherein the neck portion is formed between the body portion and the driving portion and has a second width in the radial direction of the reference rotating axis, wherein the second width is less than the first width.

An accessory tool includes an effector end including a body having first end and a second end opposite the first end, and a base shoulder adjacent the second end. The accessory tool further includes a shank coupled to the effector end. The shank includes a tool engagement portion configured to be received within a tool and having a hexagonal cross section defining a maximum outer width, a first reduced diameter portion disposed adjacent the effector end and defining a minimum outer dimension that is less than the maximum outer width, a fillet extending contiguous from the first reduced diameter portion and flaring outward to the base shoulder, and a second reduced diameter portion disposed adjacent the tool engagement portion and configured to receive a ball detent. The fillet defines a first radius of curvature, and the second reduced diameter portion defines a second radius of curvature.

A torque transmission driver is disclosed having a shaft adapted to receive and transmit torque from a torque generating source to the driver and a nib having a five or six lobe key-shape adapted to fit in a recess in a fastener, the nib being equal to or less than 0.050 in length and having lobes of substantially the same form along the entire second end portion.

A torque transmission driver is disclosed. The torque transmission driver has a drive axis and a main body with a first end portion and a second end portion, where the first end portion is adapted to receive and transmit torque from a torque generating source to the driver, and the second end portion is opposite the first end portion and has a key shape adapted to fit a recess in a fastener and has a protruding lead end having a taper between 10 and 30 and different in shape than the key shape with at least a portion of the protruding lead end initiating at the major dimension of the key shape. A torque transmission driver adapted to drive a small fasteners is also disclosed where the key shape is adapted to fit the recess of the small fastener.

An accessory tool includes an effector end and a shank coupled to the effector end. The shank includes a tool engagement portion that is configured to be received within a tool and a reduced diameter portion disposed between the tool engagement portion and the effector end. The shank defines a first length, and the reduced diameter portion defines a second length that is 10% to 45% of the first length.

A screwdriver bit device with a magnetic structure includes a screwdriver bit made of metal and including a shank having an insertion end on a front end thereof. The shank further includes an annular groove behind the insertion end. A sleeve is integrally made of plastic and includes an outer annular wall and a coupling portion surrounded by the outer annular wall. The coupling portion includes a hole through which the shank extends. The coupling portion of the sleeve further includes a flexible wall delimiting the hole and having a coupling section extending radially inwards. The coupling section is engaged in the annular groove of the screwdriver bit and slideable between front and rear stop faces of the annular groove. A magnetic ring is mounted to an inner side of a front end of the sleeve. The screwdriver bit extends through a through-hole of the magnetic ring.