| 摘要 |
<p>A dental handpiece having means for releasably holding a dental tool 24 comprises a handle portion 12 and a powerhead assembly 14 mounting a driving sleeve 18 having, near to its forward end, a forwardly facing internal taper 18b between a smaller diameter rear portion 18c and a larger diameter front portion 18d. A cylindrical chuck sleeve 26 having an axial tool-receiving bore 26a, a rearwardly facing taper 26b, a smaller diameter rear portion 26c and a larger diameter front portion 26d, corresponding to the similar portions of the driving sleeve 18, is slidably received in the bore 18a of the driving sleeve. Three radial openings are located at equally spaced positions around the tapered portion 26b of the chuck sleeve. A disc-shaped chucking die 30 having a diameter to fit slidably in the radial opening 28 is slidably received in each of the said openings of the chuck to hold a dental tool. A chuck pusher 36 is held in a socket 34 with a disc plate spring 38 interposed between the socket and the chuck pusher for axially displacing the chuck to insert or release a dental tool. </p> |
