Intermittent windshield wiper motor control

Claim 1

In a vehicle having a windscreen wiper, an electric driving motor for said wiper, and automatic parking means for causing the wiper to be driven to and to stop in a predetermined parking position when the supply of power for the operation of the wiper is interrupted; control means for said wiper motor including a first operating circuit for continuous operation of the wiper motor, a second operating circuit for operating the wiper motor intermittently, and means for selecting one or other of said circuits, said second circuit including: a thermally-controlled snap-acting single-pole changeover switch operable to interrupt the supply of power to said wiper motor with rising temperature and to restore power with falling temperature; an electrical heater connected in said second circuit to effect intermittent operation of said changeover switch, said heater being connected in parallel with the wiper motor and in series with said parking means so as to be energized via said parking means while the wiper is being driven to its said parking position under the influence of the parking means in operation; the movable contact of the said changeover switch being connected in series both with said heater and with the wiper motor, a first fixed contact of the switch which the movable contact engages upon operation of the switch with falling temperature being connected to a source of electrical power during operation of the wiper via said second circuit, and the second fixed contact of the switch which the movable contact engages upon operation thereof rising temperature being connected to said power source via said parking means during said opEration.