| 摘要 |
1,029,681. Dental handpieces. P. HAWTIN. Feb. 15, 1963 [Nov. 15, 1962], No. 43324/62. Heading A5R. In a turbine-driven dental handpiece the turbine is rotatably supported in compressed air bearings, the air supply for the bearings being separate from that driving the rotor and being charged with oil or other liquid. The turbine rotor 10 has spindles 11, 12 which are rotatable in upper and lower bearing elements 25, 26 secured in the head of the handpiece. Air bearings are formed by air spaces between the spindles and cylindrical internal surfaces 34 of the bearing elements and between the sides of the rotor and annular end surfaces 32 of the bearing elements. Air is supplied to the air bearings through a tubular duct 18, a chamber 19, an annular passage 20, a pair of axial ducts 21, 22 which communicate with annular recesses 23, 24 in the upper and lower bearing elements and apertures 28, 31 communicating with the air spaces. Oil is added to the air stream or injected directly into the bearings. Air is supplied to and exhausted from the rotor through ducts 14, 15 (Fig. 3) in the handpiece. Water may be supplied through a duct 16 and a nozzle 17 to a dental tool mounted in a chuck 13.
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