Patent GB-421339-A (GB)
Title: An improved windscreen wiper for automobiles and the like
IPC: F16L39/02
Filed: 1933-06-19
Abstract: 421,339. Windscreen -cleaners. POWELL, R. A., and NEWTON, R. W., 126, Cromwell Street, Collingwood, near Melbourne, Australia. June 19, 1933, Nos. 17394 and 19109. Convention dates, July 19, 1932 and Aug. 11, 1932. [Class 138 (i)] [See also Group XXVI] A suction-operated windscreen-cleaner for motor-cars and like vehicles comprises a hollow casing divided into two compartments by a flexible diaphragm which is reciprocated under the control of a spring-actuated valve mechanism, and through rack and pinion means causes oscillatory movement of the wiper arm. In the construction shown in Figs. 1, 2, and 4, the spindle 21 of the wiper arm 25 carries a pinion- 20 engaging a rack 19 on a rod 17. The rod is carried by a cylinder 15 attached to a flexible diaphragm 6 dividing a chamber 5 into two parts. A slot 28 formed in the rod 17 engages the end of a lug 29 carried by jaws 30 which are connected by a spring 37 to jaws 31. The jaws 30, 31 are grooved at their inner ends and pivotally engage the upper portions 35 of a fixed bracket 36. The jaws 31 are pivotally connected to one end of a bell-crank lever 39, the other end of which is connected to a slide valve 41 operating over a surface 42. This surface has three ports 43, 44, 45, the port 44 comprising the vacuum supply port, and the ports 43, 45 being connected, respectively, to the two chambers separated by the diaphragm 6 The slide valve 41 covers two ports at one time so that one or other side of the diaphragm is subjected to suction. The movement of the rod 17 acts through the slot 28, lug 29, and spring-controlled jaws 30,31, to actuate the slide valve and effect a reversal of movement of the wiper arm. For the purpose of parking the wiper in a horizontal position when not in use, a manually-operated valve is provided comprising a slide 52 movable in a block 53 formed on the underside of the chamber 5. The block 53 has three ports 56, 57, 58, the slide 52 acting to place the port 57 in communication with port 56 or port 58. The port 57 is connected to the main vacuum supply, for example, the intake manifold of the engine of the vehicle, the port 56 is connected to the port 44 associated with the slide valve 41, and the port 58 is connected to a chamber 16 adapted to receive the cylinder 15. When the ports 56 and 57 are in communication, suction is available to reciprocate the diaphragm 6 and operate the wiper, but when ports 57, 58 are connected, the underside only of the diaphragm is subject to vacuum and the cylinder 15 enters the chamber 16 until the diaphragm seats on the valve surface 62 of the chamber. The diaphragm is thus held inoperative, so that the wiper arm is held in a horizontal out-of-use position. In a modification the slide valve 41 is actuated by means of a cam surface formed on the side of the pinion 20 and engaging one end of a pivoted lever, the other end of which is connected to the jaws 30. In a further modification shown in Fig. 8, the underside of the cylinder 15 is provided with a floating valve 75 adapted to flatten out and seat firmly on the edge 76 of the chamber 16, when the wiper is being parked. In the construction shown in Figs. 9 and 11, mechanical control means for starting and stopping the wiper are provided comprising a recessed cam 50 which, when in the position shown, obstructs the movement of the slide valve 41 so that the lower side of the diaphragm is maintained in communication with a source of suction. When the cam is turned to release the slide valve, the latter is actuated by the spring- controlled snap-over jaws 30, 31 to initiate the operation of the wiper. In a further modification, the wiper is held in an inoperative position by means of a hand-actuated cam which is notched to engage one of the jaws 31 and prevent its movement.