| 摘要 |
<p>The self-tightening drill chuck includes a chuck body 1, three jaws 2 with a smooth surface, a mandrel 4 and a screw nut 3. A connecting hole 18 which correspondingly matches to an external diameter of a bottom end of the mandrel 4 is set about the axis of rotation on the upper end of the chuck body. The bottom portion of the mandrel is movably attached to the connecting hole. A retaining mechanism is installed between the chuck body and the mandrel to avoid disengagement. A pair of threads is set around the surface of the mandrel and the internal surface of the screw nut respectively for attaching the screw nut onto the mandrel. Three grooves 31 having a T shape are set on the bottom of the screw nut which engage with the upper end of the jaws 2, each transverse surface section thereof forming an unclosed curve. A nose which matches with the T- shaped groove 31 is engaged on the upper end of each jaw and the nose is movably jointed therein.</p> |
