Window lift control systems

Claim 1

A window lift control system for use in a road vehicle, comprising a motor for lifting and lowering the window, said window having an upper edge which is metallized, a pair of supply terminals for connection to a d.c. source, a reversing switch movable from an off position to first and second operative positions in which the motor is operated to raise and lower the window respectively, a control circuit which when energized prevents raising of the window, said control circuit having a pair of input terminals, one of which is connected to one of the supply terminals, and the other of which is connected to the other supply terminal by way of said reversing switch when the reversing switch is in said first position, the input terminals of said control circuit providing power to an inverter, which in turn provides power to an induction loop inside the vehicle, power being fed from said induction loop to said control circuit to prevent raising of the window if said metallized edge is touched while the reversing switch is in said first operative position.

Claim 3

A system as claimed 1 in which said control circuit includes a field defect transistor which on receiving an input as a result of said metallized edge being touched provides a gate signal to a thyristor which energizes a relay.