| 摘要 |
1,076,506. Dental handpieces. KALTENBACH & VOIGT. Feb. 4, 1966 [March 23, 1965], No. 4990/66. Heading A5R. A clamping device for holding a rotary tool in the drive bore or bush of a dental handpiece comprises at least two flexural springs, for example leaf springs, located at equal intervals about the axis of the bore or bush and arranged to be resiliantly yieldable radially of the axis. The central portion of each spring may be arcuate and inwardly curved towards the drive bore or bush axis, the axially opposite ends of each spring being held radially relative to this axis and being angled relative to the arcuate central portion so that they are parallel to or coplanar with each other. Figure 1 illustrates the device applied to a handpiece having a toothed gear drive. At the forward end of handpiece neck 1 is head housing 2 which is closed at one end by cover 3 and inside which driving sleeve 4 and flanged sleeve 5 are mounted by means of ball bearings 6 and 7, the bearings being separated by spacer sleeve 16 which has a nose 17 engaging in groove 18 of the head housing to prevent rotation of the spacer sleeve relative to the head housing. Bearing sleeve 8 is fixed at one end to the driving sleeve and to tool guide sleeve 10, in which the shank of a tool (not shown), for example a burr, may be inserted, and at its other end seats with a sliding fit in the flanged sleeve and about tool guide sleeve 9. The tool guide sleeves are provided with annular recesses 11 and 12 into which are inserted end portions 15 of flexural springs 13 (only one of which is shown). The end portions of each spring are wider than the arcuate central portion so that end portions of adjacent springs abut laterally to set the central portions at equal intervals about the tool bore axis. Each spring preferably has an arcuate cross-section in at least that region which is to grip the tool shank, the radius of curvature of the inner face of this region corresponding to the tool shank radius. The device may also be applied to handpieces driven by a fluid-operated turbine, Fig. 3 (not shown), or by belt and pulleys. |
