GB1012293A - Windscreen wiper - Google Patents

Abstract

1,012,293. Control of D.C. motors. FORD MOTOR CO. Ltd. Sept. 3, 1964 [Oct. 16, 1963], No. 36058/64. Heading H2J. [Also in Division A4] A windscreen wiper motor 22 is energized continuously when the movable contact 14 of a switch 15 is engaged with a terminal 18, but when the contact 14 engages a contact 19 a switch 35 de-energizes the motor 22 at the end of each wiping cycle and a delay device energizes the motor 22 intermittently at a time interval that can be selected to be greater than the period of one wiping cycle so that the wiper blade is stationary for a selected period at the end of each wiping cycle. The delay device comprises a capacitor 65 which when charged up through a variable resistor 52 and resistor 63 causes a transistor 55 to conduct and then discharges through the latter. The voltage at the base terminal 73 of the transistor 55 then rises to cause a rectifier 58 to conduct. The motor 22 is then energized through the rectifier 58 to move the wiper blade away from the parking position thus rotating a cam 32 to permit an arm 34 of a switch 35 to move from a contact 38 to a contact 37 to short circuit the rectifier 58. The motor 22 continues to operate until the wiper arm again returns to its parking position when the cam 32 forces arm 34 into engagement with contact 38. The capacitor 65 then charges again.