GB776488A - Improvements in combination electric switches - Google Patents

Abstract

776,488. Secret contact combination switches. HARPER, L. Jan. 3,1956 [March 25, 1955], No. 8677/55. Class 38(5) A combination switch comprises a plurality of lettered or like rings 5 rotatable' about a drum 1 and each carrying a spring- pressed ball 8 or other contact which balls are adapted, when the rings are set in their correct position with respect to a fixed mark, to bridge gaps in an electrical circuit. In the form shown there are three rings and the balls 8 are adapted to lie between and so connect segments of two parallel conductors 2, 3, (Fig. 6) each of which is cut into two segments separated by a gap 2c or 3c. Thus the current flows from 3a to 2a, 3b and 2b. The conductors 2, 3 are disposed in, a fixed insulating drum 1 about which the rings revolve and the segment 2b is connected to a metal rod 4 connected to one lead 32 of the circuit while the segment 3a is connected to the other lead 21. In a modification, Figs. 7 and 8 (not shown) the balls 8 bridge gaps in a single straight divided conductor. The drum 1 is formed with ten longitudinal grooves 14 corresponding to the 10 letters on each ring and adapted to be engaged by the balls 8 when the rings are in other positions than the "set" positions. The lettered rims of the rings 5 may be rotated relatively to the main portions to vary the combination, the main portions being held in the set position while this is being done by a pin inserted through holes 35, 34.