GB153980A - A switch for closing electrical circuits only by knowledge of a secret combination of symbols - Google Patents

Abstract

153,980. Leede, E. F. W. Aug. 26, 1919. Secret contact-combination switches for the ignition circuits of motor-vehicles, telephones, &c. comprise a number of insulating-disks 1 mounted co-axially on the reduced shank 2 of a fixed insulating end-member 3 which carries a contact u connected to the circuit by the terminal 10 and held in place by the other contact-carrying end-member 4, which screws upon the end of the shank. In the construction shown, the middle rotatable disk is provided with a cupped bridging- contact 7' located in one of a number of holes coaxial with the circuit contacts 5. In one each of the similar holes in the other rotary disks 7, a spring plunger contact 6 is mounted so that, when the correct combination of symbols on the periphery of the disks is arranged in relation to one another and to the fixed end pieces, a through circuit is completed, as shown. The combination may be changed by moving one or both of the spring plunger contacts to another hole in its disk, or the sequence may be changed without altering the combination by interchanging the two outside disks. The switch may be locked in the contact or non-contact position by a bolt passing through vacant alined holes 9 in the disks and end members.