| 摘要 |
1282372 Rotary switches SIEMENS AG 15 Sept 1970 [16 Sept 1969] 43960/70 Heading H1N A control device for rotary switches comprising a modular assembly of a rotation-limiter, together with a detent mechanism and/or a spring-return device, in a cylindrical housing through which passes a coaxial switch spindle provided with a flat, has the inner surface of the housing profiled throughout its length and at least said rotation-limiter comprises co-operating members which are adjustably keyed respectively to said profiled surface and to said flat on said spindle so as to provide an adjustable range of rotation and, optionally, a choice of spring- return positions. As shown, casing 1 has axially extending ribs 20 and shaft 10 has two flats 11. Adjustable rotation limiter.-Each of two discs 16 keyed on shaft 10 has a peripheral lug (9, Fig. 4, not shown) which abuts an inwardlyextending lug (8) on a respective annular stop washer 2, itself keyed to housing 1 by tongues 19 selectively located between the ribs 20. Detent mechanism.-A ball 7 carried in a disc 17 keyed, by flats 11 to shaft 10 is urged by compression spring 14 into recesses (22, Fig. 5, not shown) on disc 3 held stationary by a tongue engaged in a groove between ribs 20. Spring return mechanism.-A torsion spring 12, held pre-stressed in a casing 13 keyed to shaft 10, has projecting ends 6 which engage lugs 5 on respective stationary discs 4 when the shaft is turned to end positions determined by the angular locations of discs 4 in casing 1, the discs having peripheral tongues engaged between ribs 20. The spring 12 is then stressed further to return the shaft 10 to its adjacent previous position on release of the control knob (not shown). The inner cylindrical wall of the housing may be provided alternatively with a single longitudinal groove or projection only. In this case the various elements keyed to the housing must have a plurality of peripheral projections or grooves to provide for adjustment. The detent mechanism may be omitted (Fig. 2, not shown) to provide a switch with a central neutral position and two spring-return positions. The spring return mechanism may be omitted if this function is not required. The length of the housing may be shortened by fitting the torsion spring around the compression spring, or, by suitable spring construction, one spring may provide both the return and detent forces. |
