| 摘要 |
A bi-directional, self-tightening drill chuck suited for surgical and other medical applications in accordance with the present invention includes a chuck body having an internally tapered opening at one end that is defined by first and second cam surfaces and a central, longitudinally extending cannula or passage formed through the length of the chuck body. A plurality of tapered gripping rollers are located within the opening and are resiliently urged against the cam surfaces throughout a range of adjustment by a spring retainer which includes rearwardly extending spring arms. A control sleeve is adjustably mounted on the chuck body and includes a thrust bearing at one end for contacting the forwardly facing ends of the tapered rollers and a split retainer assembly at its other end for contacting the rearwardly extending ends of the spring arms such that the tapered rollers and the spring retainer move as a unit relative to the chuck body when the control sleeve is adjusted to cause the tapered rollers to grip a selected tool bit. The chuck can accept a tool bit, such as a common twist drill, or other implements at one end through a tool receiving opening formed in the control sleeve or from the opposite end through the cannula. In operation, the torque transmitted through the chuck causes the tapered rollers to shift circumferentially relative to the cam surfaces and proportionally increase the gripping force applied to the tool bit.
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