GB1374996A - Windscreen washing systems for road vehicles - Google Patents

Abstract

1374996 Windscreen cleaning systems LUCAS ELECTRICAL CO Ltd 15 June 1972 [2 Oct 1971] 45950/71 Heading A4F [Also in Division H3] A windscreen cleaning system comprises a windscreen wiper motor 43 and a washer motor 25 both under the control of a manually operable switch 15 in an electric circuit comprising three relays 22, 32, 39, the relays being so arranged together with delay means that, upon momentarily closing switch 15 manually, the washer motor 25 is energized immediately and the wiper motor 43 is energized a predetermined time interval later, both motors 25, 43 being maintained in their energised condition for different predetermined time periods. As shown, the motors 25, 43 are energised only when associated switches 24, 42 under the control of associated relays 22, 39 are closed, the relays 22, 39 being energized when associated transistors 21, 38 are rendered conductive by suitable control of their base currents. When switch 15, which is connected to a battery 11 by way of an ignition switch 12, is closed momentarily, transistor 21 is rendered conductive immediately for a time period depending on the characteristics of a capacitor 17 and resistors 18, 19 so as to energize winding 22 and thereby actuate washer motor 25 for that time period (e.g. two seconds). Depending on the characteristics of a resistor 27 and capacitor 28, a transistor 31 is rendered conducting a short time period (e.g. one second) after the initial energization of the motor 25 to energize relay 32. This energization renders transistor 38 conducting, causes relay to be energized and therefore causes actuation of motor 43, the characteristics of the capacitor 35 and resistors 36, 37 being chosen to maintain the transistor 38 conducting and thereby the wiper motor 43 actuating for a predetermined time period (e.g. five seconds) after the washer motor 25 is de-energized.