Patent GB-515965-A (GB)
Title: Wind screen wipers, particularly for motor vehicles
IPC: B60S1/08
Filed: 1938-06-17
Abstract: 515,965. Windscreen-cleaners. ROVER CO., Ltd., LUCAS, Ltd., J., HUYTON, A., PURDEN, R. H., and IVERSEN, P. A. SCOTT-. June 17, 1938, Nos. 18004 and 26786. [Class 138 (i)] A windscreen-wiper is driven by a reversible motor and a variable-throw crank, reversal of the motor effecting automatically a variation of the throw of the 'crank, so that in one direction of rotation of the motor the wiper is given a normal wiping oscillation or reciprocation, and in the other it is given a wider oscillation for parking purposes. As shown in Fig. 1, the wiper a is oscillated by a rack d reciprocated by a crank pin f engaging in a spiral groove g in a crank disc h. The latter is driven 'by a reversible electric motor i. When the disc is rotated in the direction of the arrow, the pin abuts the inner end of the groove and imparts a wiping oscillation to the wiper. When the motor is reversed, the pin moves to the outer end of the groove and imparts a wider, parking, oscillation to the wiper. The motor is controlled by a reversing switch, Fig. 10, comprising fixed, contacts 11 arranged in the motor circuit and two sets of contacts 15, 16 arranged on a plug 10 controlled by a knob 9 and spring 13. When the knob is pulled out, the contacts 11 and 15 engage to drive the motor in a direction corresponding to the wiping oscillation of the wiper. When it is pushed fully in, the contacts 11 and 16 engage to reverse the motor and park the wiper. When the knob is released, the spring 13 moves the plug to an " off " position where the contacts 11 engage a locking groove 12. In a modification, the crank pin is carried by a slide which is moved automatically across 'the face of the crank disc when the motor is reversed. In another modification, the crank pin carries a bar, and the point of connection of the bar to the rack is varied automatically when the motor is reversed. In another modification, Fig. 8, an eccentric v rotatably mounted on the crank pin and held to it frictionally by a spring 2 and surface z, is received rotatably in a strap w at the end of the rack. When the motor is reversed, reversal of the eccentric in the strap is ensured by the frictional.connection 2, z. Stops x, y determine the extreme positions of the eccentric. A projection on the eccentric may open a switch in the motor circuit when the wiper is in parked position, this switch being short-circuited when the main switch is in position for normal operation of a wiper. A reversible mechanical drive for the crank disc, Fig. 12, comprises a shaft 23 driven from a moving part of the engine and carrying a bevel-wheel 22 in mesh with two bevel wheels 21 rotatable on a shaft 18. The latter is slidable in a casing 20, carries a clutch member 26 co-operable with a recess 27 in each wheel 21 and is connected to a flexible shaft 17 which drives the crank disc. The shaft 18 is controlled by a lever 29, which is biassed by a spring 28 so as to return to a neutral position after it has been moved to a position corresponding to the parking of the wiper. One Provisional Specification refers to Specification 505,253, and to the provision of a slipping clutch in the crank to prevent damage in case of obstruction.