| 摘要 |
A collet of somewhat flexible plastic for holding a dental tool in a dental handpiece, has an inner body which fits within a socket in the burr tube of the handpiece, and at its outer end extends outwardly into a hub and then rearwardly into a cylindrical skirt which fits between the outer surface of the bearing for the burr tube and the inner surface of a counterbore in the handpiece. Centrifugal force caused by rotation of the burr tube flares the skirt outwardly against the counterbore surface to provide a seal therebetween. In a modification the skirt slants outwardly to contact the counterbore surface when the skirt is stationary. A modified skirt tapers from its connection to the hub to the skirt end. In another modification, the collet has a bore in its inner end, with the handpiece end cap, the driven gear and the burr tube having bores aligned with the collet bore so that a burr extractor pin can extend through the bores to push the dental tool out of the collet. The extractor pin in one form has a flat head, and in another form has a looped end for insertion of a finger.
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