Abstract: An automotive theft preventing circuit including a battery, ignition switch and starter connected in series. An anti-theft device connected in series therewith comprising a metallic adjusting screws contact plate and a spring loaded contact pins plate underneath it. A coded plastic card is underneath the last-mentioned plate having a plurality of upstanding pins and a plurality of holes in vertical and horizontal alignment with openings in the spring-loaded contact pins plate. Some of the metallic screws are surrounded by insulation to make the circuit more theft-proof.

Abstract: An anti-theft device comprising a compartment having lowermost spring plate with spring clips, some of which have insulating tops, others having metallic tops so that if an incorrect anti-theft card is used, it will raise the contacts energizing the top plate to sound an alarm by energizing the horn and at the same time energizing the relay making it impossible to complete the starter circuit by the ignition switch.