Chuck for electric hand drill - has major components made from plastics to provide sufficient frictional grip when hand-tightened

摘要

The plastics base (58) of the chuck is screwed to the drill drive shaft by an internal thread (26) and a steel countersunk screw (34). The metal jaws (44) are held between a tapered metal sleeve (50) and a steel washer (40) by the pressure of the plastic outer collar (20) which screws onto a thread (26) on the base (58). When a drill bit is inserted into the assembled chuck, the collar is turned in the opposite direction to the base by hand pressure on the fluted outer surfaces. This slides the sleeve down over the jaws (44) against the pressure of the springs (46) until the drill bit is tightly gripped. The plastics material has a low slip resistance coefficient which allows a firm grip on the bit using only manual tightening.