| 摘要 |
1,242,077. Dental handpieces. ATLAS COPCO A.B. 17 Dec., 1968 [29 Dec., 1967], No. 59863/68. Heading A5R. [Also in Division B3] A chuck control mechanism for dental or other tools comprises a tubular housing 1 with a drive shaft 6 and a chuck 15 for gripping the shank of a tool (not shown) mounted therein, a tubular carrier member 14 axially movable and rotatably mounted over a portion of said shaft, with a frustro-conical surface 20 engaged by a corresponding surface 17 on the chuck, and an axially fixed control ring member 42 rotatably mounted on the outside of the housing and acting on an axially displaceable ring segment 35 which engages with the tubular member 14 so that rotation of the ring in one direction tightens the grip of the chuck, and in the other direction disengages it. The chuck 15 consists of a sleeve with slots (19), Fig. 3 (not shown) extending parallel to the axis from both ends, and has tapered ends, 17, 18, and 18 engaging a tapered surface 12 in a sleeve portion 11 of the shaft 6. A spring 24 acts between a shoulder 13 of the shaft 6 and a bushing 21 which is fixed on the member 14 so that the surface 12 is pressed towards the surface 20, and the tapered surfaces 17, 18 of the chuck are subjected to a pressure which results in a gripping action on the shank of a tool in the chuck bore. The carrier member 14 is rotatably mounted in ball bearings 8, 9, the outer races of which are fitted in a tube 33 which is a sliding fit in a bore 32 of the tubular housing 1. Ring segment 35 is provided with screw threads 40 cooperating with threads 41 on the inside of the ring 42. Alternatively, camming means may be provided, to move the ring segment parallel to the housing axis to engage with a shoulder 45 on the carrier member 14 to brake its rotation and then relieve the chuck 15 of axial pressure from spring 24, whence the shank of the tool may be pulled out of the bore 16 of the chuck. Shaft 6 is rotatably mounted in the tubular housing 1, partly directly in a ball bearing (7), Fig. 1a (not shown) and partly indirectly in ball bearings 8 and 9. A plurality of ring segments 35 may be provided. |
