| 摘要 |
1,196,656. Dental handpieces. HONEYWELL Inc. 8 Sept., 1967 [12 Sept., 1966], No. 41124/ 67. Heading A5R. A dental handpiece comprising a rotor adapted to support a dental tool and to be driven operatively by a fluid under pressure, for example compressed air, is provided with a cooling manifold having a central bore through which a dental tool mounted in the handpiece will pass, the exterior surface of the manifold surrounding the outer end of the bore being generally planar except for an annular projection surrounding the outer end of the bore and being provided with a plurality of orifices communicating with at least one passage formed in the manifold and intended to supply cooling fluid or fluids to the orifices which are arranged so as to direct the fluid or fluids on to a dental tool mounted in the handpiece. In the handpiece illustrated in Figure 1, the annular projection 63 on the exterior surface 62 of the cooling manifold 60 immediately surrounds the central bore 61 and the manifold is provided with two separate passages 64, 65 through which different cooling fluids, for example air and water, may be supplied to respective orifices 67, 68 by conduits 69; the provision of such an annular projection is stated to prevent ingress of debris into the interior of the handpiece through the annular gap formed between the manifold and a dental ,twos mounted in the handpiece and thereby to lessen wear of the rotor bearings which, in the handpiece illusstrated, are constituted by air bearings.
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