Ratchet coupling for tool, especially screwdriver, comprises drive part, grooved control ring, toothed blocking parts and ratchet ring with protruding Allen key socket

摘要

The coupling includes a drive part (21) with a ring (211) in its middle section for placing inside a round cavity in a control ring (22). The rectangular-shaped rear end of the drive part is inserted into a stepped central bore in a handle (20). The flat rectangular-shaped front end of the drive part has a pair of spaces (212) on it top and bottom sides for locating two pairs of blocking parts (23-26), each part containing a first round recess (231, 251) opposing a round recess in the other part in the pair, so that a pair of springs (201, 202) can be secured inside these two pairs of recesses. The blocking part also has a toothed slanting surface. A second recess (213) is located in a lateral side of the drive part for locating a second spring (214) and a first steel ball (215). A pair of third recesses (216) are spaced apart in the flat rectangular-shaped front side of the drive part and used to hold two second steel balls (217). The control ring has four r otary pins (223-226) located diagonally opposite each other on the inner periphery of this ring. Three positioning grooves (227-229) are provided on the inner periphery of the control ring. A cap-shaped ratchet ring (27) is fitted over the drive part in a sleeve-like manner and has teeth around its inner periphery for engaging with the teeth on the blocking parts. An Allen key socket (271) protrudes from the centre of the front side of the ratchet ring. A round cap (28) covers the ratchet ring and drive part. The cap is joined to the control ring by high-frequency welding and contains a central bore (281) through which the Allen key socket protrudes. The control ring is turned in order to secure or release a tool bit.