Einrichtung zum intermittierenden Betrieb eines Fahrzeugscheibenwischers

1,065,116. Windscreen wipers. ROBERT BOSCH G.m.b.H. July 3, 1964 [July 4, 1963], No. 27475/64. Heading A4F. [Also in Division H2] A windscreen wiper motor is controlled by a manually operable switch which in at least one position causes the motor to operate continuously and in another position energizes a periodically operating electronic impulse generator to cause the motor to operate intermittently. When the rotary contact arm 40 of the switch 27 is set to position a relay coil 26 is energized continuously from a battery 20, and relay contacts 23 are closed to energize the main and shunt field windings 101, 1011 of the motor 10. On moving the arm 40 to position b a lug 53 on a rotary plate 54 opens contacts 50, 51 to de-energize the shunt winding 1011 so that the motor rotates continuously at a higher speed. For intermittent operation of the motor 10 the arm 40 is set between the positions c, d when an astable multi-vibrator 28 including transistors 60, 61 is energized to supply current pulses to the relay coil 26 of durations determined by a variable resistor 68 the setting of which is determined by the position of the arm 40, which is mounted on a spindle 36 which carries the contact arm 69 of the variable resistor 68. During each interval in which the relay coil 26 is deenergized the motor continues operation to complete a wiping stroke, being supplied through a line 22 including a switch 30, 31 which is opened by a rotary cam 34 at the end of a wiping stroke.