| 摘要 |
In a dental prophylaxis angle, an angle housing defines a main passageway and an ancillary passageway communicating therewith and extending at a substantial angle thereto. A drive shaft extends through the main passageway, while a cup holder is rotatably disposed in the ancillary passageway, the cup holder being drivingly coupled to the drive shaft. A flexible prophy cup is mounted to the cup holder, and a bearing is rotatably disposed in the main passageway about the drive shaft. The bearing has a snap-lock element projecting into a recess provided in the housing, thereby fixing a longitudinal position of the bearing with respect to the housing and holding the drive shaft in driving engagement with the cup holder. The prophy cup is coupled to the cup holder via a ball and socket joint and is provided in a region about the ball and socket joint with a flexible skirt defining an annular groove, the cup holder having an annular seat projecting into the groove. The seat preferably has an outer surface inclined at an angle with respect to a longitudinal axis of the cup holder. The skirt engages the outer surface of the seat and bends upon such engagement during use of the prophylaxis angle. In addition, the prophy cup is provided with outwardly extending projections in the groove, the seat being formed with inwardly extending teeth meshing with the projections for driving the cup.
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