GB1017400A - Windshield wiper arrangements - Google Patents

Abstract

1,017,400. Windscreen wipers. FORD MOTOR CO. Ltd. Sept. 3, 1964 [Oct. 21, 1963], No. 36064/64. Heading A4F. [Also in Division H2] In a windscreen wiper system in which a wiper blade is operated intermittently for cleaning the windscreen in light rain without smearing, an electric wiper motor 22 is de-energized at the end of each wiping cycle, a capacitor 87 charges and then discharges at a certain voltage to re-energize the motor 22, and re-energization of the motor 22 prevents further charging of the capacitor. In the system illustrated the wiper 26 is operated continuously when conjointly movable switch contacts 43, 47 are engaged with contacts 45, 49 respectively, and intermittant operation is obtained when the switch arms 43, 47 are engaged with terminals 46, 51, respectively. When the terminals 46, 51 are so engaged the capacitor 87 is charged from a battery 10 through a resistor 68 and a variable resistor 85. At a certain voltage the capacitor 87 is discharged by a unijunction transistor 91, and a rectifier 72 is rendered conducting to energize the motor 22 through line 83, contacts 47, 51, and line 57. The motor 22 rotates a cam 32 acting upon a follower 33, which in the parked position of the wiper holds a contact arm 34 in engagement with a contact 38, but on rotation of the motor the cam 32 permits a spring 36 to move the arm 34 into engagement with a contact 37. The motor 22 is then energized through the contacts 34, 37, and the rectifier 72 is extinguished by the earthing of its cathode 73. When the wiper again reaches the parking position the cam 32 disengages the contacts 34, 37 to stop the motor and the capacitor 87 is again charged to repeat the motor starting and stopping sequence.