| 摘要 |
PCT No. PCT/CH81/00113 Sec. 371 Date Jun. 10, 1982 Sec. 102(e) Date Jun. 10, 1982 PCT Filed Oct. 8, 1981 PCT Pub. No. WO82/01309 PCT Pub. Date Apr. 29, 1982.In a dental turbine, having a laterally displaceably arranged rotor assembly including a shaft mounted in upper and lower ball bearings and having its lower end protruding through a bore provided in the nose of the turbine and forming a gap or space with the bore for accommodating the lateral displacement of the shaft lower end thereat a protective sleeve (1) is fitted to the outer ring (2) of the lower ball bearing, and extends below the bearing, then along the lower end of the shaft (4) and into the space (5) formed between the shaft (4) and the bore (6) in the nose (7) of the turbine to provide a relatively minute gap or space between the inner surface of the lower portion of the sleeve and the lower end of the shaft and a resultant reduced size gap or space between the outer surface of the lower portion of the sleeve and the inner surface of the bore in the nose. The protective sleeve (1) which follows any lateral movement of the rotor assembly and a ring of soft material (13) received in compressed state between the outer surface of the lower portion of the sleeve and the inner surface (15) of the turbine head, i.e. rearwardly or upwardly of the bore in the nose, prevent waste material of any kind which might otherwise have penetrated into the interior of the turbine through the minute gap or space (10) and/or the reduced size gap or space (12), from reaching the vital parts of the rotor.
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