摘要 |
The present transmission gear for a dental handpiece generally has a handle portion including a biased guide slot and a holding sleeve fixedly held in the handle portion, a first cylindrical hollow driven shaft, a second driven shaft having at its rear end portion an axial central cavity and fixedly inserted into the first driven shaft, a shiftable clutch shaft having a drive pin, a collar bearing including a slidable pin and a crossed male lug and journaled rotatably in the central hollow, a planetary gear train provided at the rear end portion of the clutch shaft, and a drive gear coupled to the motor to be engaged with the clutch shaft whereby the clutch shaft is either coupled to the drive shaft or disengaged therefrom by the alternative rotation of an operating ring to deliver either a direct transmission of the motor rotation or reduced speed rotation thereof to a dental tool.
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