| 摘要 |
1,189,884. Dental engines. MORITA SEISAKUSHO K.K. 3 May, 1967 [25 Jan., 1967], No. 20594/67. Heading ASR. [Also in Division F2] A fluid bearing assembly, in a dental handpiece, comprises a shaft 2 carrying turbine blades 3 and supported in fluid bearings 5, 6, a first passage 16, 12 opening toward the front surfaces of the turbine blades, a second passage 15 opening towards the rear of the turbine blades, said passages being connected to the fluid gap of the bearings, air being supplied by the first passage and vented to atmosphere by the second passage to provide rotation of the shaft, and vice versa to stop the shaft. During shaft rotation air is supplied from passage 16 by passages 13, 14, grooves 7, passages 10 to the fluid bearings. During stopping of the shaft, air supplied by passage 15 maintains the air pressure in housing 1 above atmospheric and therefore prevents inhalation of air contaminated by dust or other .particles. The flow of air is controlled by solenoid valves (21, 22, Fig. 2, not shown), closure of foot switch (37) energising valve (21) to connect supply line (29) to passage (16), release of switch (37) deenergising valve (21) while relay (38) energises valve (22) for a short period. |
