Theft alarm for fitting to motor vehicle windows - uses continuous wire loop on inside of all windows connected to alarm unit

摘要

The proposed circuit increases the vehicle protection provided by a normal alarm which is associated with unauthorised opening of doors and starting of the engine. By extending the supervision to the vehicle windows thefts from inside the vehicle by breaking the glass also set off the alarm. A wire conductor (2a-2e) is placed across each window on the inside of the vehicle. All these conductors are connected in series to form a loop which is then connected (3,4) to the alarm operating unit. Breaking a window results in breaking the wire thus opening the loop and initiating the alarm. For large windows two spaced wires may be employed. The wires can be fitted with plug connectors to join with fittings inside the vehicle. This enables the wires to be removed when the vehicle is in use.