Patent GB-1381138-A (GB)
Title: Control elements for electrical systems
IPC: H01H36/00
Filed: 1972-12-12
Abstract: 1381138 Component assemblies; magnetic switches SIEMENS AG 12 Dec 1972 [15 Dec 1971] 57298/72 Headings H1R and H1N A prefabricated universal control element for an electrical system comprises a two part housing 1a, 1b screwed together through corresponding bores 101, 102. A printed circuit board 2 is symmetrically disposed between the housing halves and carries the electrical elements necessary for the control functions of the element. E.g. magnetic reed contacts 201 are mounted on distance pieces 202, and a holder for incandescent lamp 204 is riveted in bore 206, with an indicator amplifier 207. The conductor paths of the circuit board terminate at contact strip 208. A slide 3 is movable in the housing parallel to the circuit board located in rectangular openings 111 of transverse ribs 110, and itself has an H-shaped opening 302 defining guide pins 303 locating a compression spring 301; while sideways projecting resilient tongues 304 retain the slide in opening 111 by engaging the underside of ribs 110. The slide also carries dependent feet 305 one of which carries a switching lug 306. A rotary ratchet wheel 4 on an axle 403 is journalled in bores 112 of the housing halves; and its 4 tooth pinion 402 is aligned with slide 3 while its axle traverses a bore in circuit board 2 and carries a longitudinally poled permanent magnet 404 enclosed by a cruciform pole plate 405 secured concentrically with the axle to a boss enclosing the bore 112 of housing half 1a. A cap 5 with an indicating panel transmitting light from the lamp 204 is arranged to cover the control element, and may be longitudinally movable in connection with slide 3. Each element is inserted from above into a console, and lugs 113 of halves 1a, 1b engage recesses of a spring contact strip 7, while longitudinal screws 6 engage the console base. Horizontal slots 116 of the housing halves 1a, 1b dissipate heat, and projections 117 at the corners of each element mutually engage. The springs of plural contact strips 7 are located in chambers of a housing mounted on a carrier plate (not shown) with dependent terminal pins forming a grid or raster, which may be interconnected to signal lines, e.g. by wire wrapping enabling easy interchangeability of units. The slide 3 engages a groove 502 of cap 5 and is retained by lug 308 engaging opening 503 of rib 504 so that the cap is movable longitudinally of the assembly. Downward operative displacement of the slide engages lug 306 with pinion 402 which rotates anticlockwise to overcome the retentive force of magnet 404 on pole plate 405, when the pinion is magnetically impelled into a 90 degree spaced position by interaction of the magnet and the pole plate, so that the next tooth engages lug 306. On release the slide returns leaving the magnet in position to locate the ratchet wheel and freeing the tooth in readiness for a subsequent operation. A second switching lug 307 may be provided on slide 3 which on release returns the ratchet wheel 4 into its original position when the cap is released under influence of spring 301, so that the device then acts as a key switch. Rotation of the magnet 404 initiates required electrical functions, e.g. by operating closure of reed contacts 202 when the magnet is in alternate stable positions, and the contacts are connected over printed circuits of board 2 to corresponding contacts 208 and terminal pins 304. The incandescent lamp 204 is controlled over amplifier 203 to indicate a required switching state. In a modification (Fig. 4, not shown) a toggle lever mounted in a fixed cap may cam operate the longitudinally movable slide. The control elements may alternatively comprise only indicator lamps mounted on opposite sides of the circuit board, and the lamps may be replaced by luminescent diodes. Reed contacts may be replaced by magneto-restive switching elements. A movable button may be mounted in a fixed cap to operate the slide, and the simple longitudinally poled magnet is replaceable by a multipoled magnet.