Multiple switching device for automatic telephone systems
United States Patent 3080457

921,625. Press-button retractive switches. TELEFONAKTIEBOLAGET L.M. ERICSSON. Sept. 15, 1959 [Nov. 3, 1958], No. 31474/59. Class 38 (5). [Also in Group XXXIX] A switching device includes a plurality of push-buttons 9, Figs. 1, 2, operable from one side of a mounting plate 10, each push-button when operated displacing a member 2 against the action of at least one spring 13 and operating a switch contact 6 individual to the pushbutton and a switch contact 3 arranged to be actuated by the member 2. Member 2 is a ring and is of insulating material or is covered by insulating material. A core 11 secures mounting plate 10 to a front plate 1. Each push-button shaft carries a spring 12, one end of which bears against the button proper while the other end bears against disc contact 6 which is loosely mounted on the button shaft and rests against an annular support 15 fixed to the button shaft. The free ends of the shafts touch ring member 2 which, when no button is pressed, is held against the mounting plate 10 by three springs 13 carried by posts 14 fixed to plate 10. The contact 3, of bar form, normally connects contacts 4 and 5. On pressing any button 9, its shaft urges the adjacent part of ring 2 away from plate 10 against the action of the nearest spring 13 and breaks connection between contacts 3 and 4. At the same time disc 6 connects contacts 7, 8 associated with the pressed button 9. A11 contacts 4, 5 are in series so that a common circuit is broken on pressing any button 9. Alternatively, by arranging bars 3 so that a connection is made on pressing a button and connecting the pairs of contacts 4, 5 in parallel, the circuit is closed on pressing any button. In a modification, Fig. 3, two springs 13 mounted on posts 14 urge contact wires 16 against contacts 4, 5 and urge ring 2 towards plate 10. At least one connection between a wire 16 and contacts 4, 5 is broken on pressing any one of the buttons 9.

Axel, Jansson Tage
Sture, Ekwall Sven
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200/16A, 379/369
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US Patent References:
2951916Electric contact device1960-09-06