Electrical anti-theft system

Claim 1

An electrical anti-theft system in which a necessary protected electrical circuit is controlled by relay contacts which turn the protected circuit to the on position only if selected pairs of momentary contact electrical switches are energized in the proper sequence and prevents the protected circuit from being supplied with electricity if other available momentary contact switches are turned on during the unlocking operation, comprising, a panel board on which a multiplicity of operating arms of individual momentary contact switches are mounted, with each switch being identified individually and with the majority of said switches being connected in parallel to each other, said parallel assembly of switches being connected in series with the coil of a first relay, said circuit being in series with a source of power and with a master control switch such that once the master control switch has been turned on, the momentary activation of any one of said switches of the parallel assembly will turn said first relay to the on position, said first relay being fitted with a normally open switch joined in parallel with said bank of switches to maintain said relay in the on position once it has been turned on, and said first relay being fitted with a normally closed contact which is located in series with the coil of a second relay so that said second relay cannot be turned on while said first relay is in the energized mode, with the said protected circuit connected in series with a normally open contact of said second relay so that the said protected circuit cannot be operated unless said second relay is in on condition, the coil of said second relay being connected in series with the aforesaid normally closed contacts of the first relay and in series with each of two of the momentary switches mounted on the panel board, such that momentary operation of both of said two series-connected switches is required to turn the second relay on, with the first relay remaining in the off position in order to switch on the protected circuit.