Patent GB-877191-A (GB)
Title: Improvements in windscreen cleaning systems
IPC: B60S1/48
Filed: 1957-11-22
Abstract: 877,191. Windscreen cleaners. TRICO PRODUCTS CORPORATION. Nov. 22, 1957 [Nov. 28, 1956], No. 36516/57. Class 138(1). A windshield cleaning system comprises a wiper motor 17, a control 34 for controlling the operation of the wiper motor, a coupler 23 which is operable by pressure fluid for controlling the wiper motor operation to the exclusion of the control 34, a washer including a reservoir 41 for cleaning liquid and a pump 44 which is operable by pressure fluid to discharge cleaning liquid from the container for spraying an associated windscreen, a co-ordinator unit 43 arranged to regulate the flow of pressure fluid to the coupler and to the pump concurrently and for a predetermined time and a spring 49 which, when there is no pressure fluid flowing in the pump, causes the pump to draw in liquid from reservoir 41. To operate the wiper without the washer, knob 38 on control 34 is turned and pinion 37 engages rack 36 actuating cable 19 which is connected to motor control valve 18. By this means it is possible to vary the speed of operation of wiper motor 17. To operate the combination of washer and wiper, knob 113 is depressed and the attached rod 112 unseats valve 107 venting to atmosphere annular chamber 106, nipple 105, pipe 73, nipple 72 and chamber 64 of co-ordinator unit 43. Diaphragm 66 within chamber 64 is then under the influence of compressed air from supply pipe 76 on its underside, causing the said diaphragm to move upwards and compress spring 68 while an equal movement of conical valve 69, rod 87 and conical valve 84 seals the gap between rod 87 and its passageway 88. Compressed air from pipe 76 is put into communication with passage 77, T-junction 114, pipe 32 leading to coupler 23 and pipe 56 leading to pump 44. Air acting on piston 29 moves it against spring 31 moving shaft 24 thus setting the motor into operation while the air delivered to the top surface of diaphragm 48 actuates the pump and delivers cleaning liquid through pipe 58 via valve 104, and pipe 101 to spray nozzles 117. A small proportion of the liquid which flows through pipe 58 passes through passage 93, and enters chamber 81 by way of non-return valve 86. When knob 113 has been released, air pressure can begin to build up on to the surface of diaphragm 66 due to the limited flow allowed through passageway 70 and the diaphragm starts to return to its original position under the action of spring 68. However, its complete return is prevented by the presence of liquid entrapped in chamber 81 which can only escape by way of the needle valve 98 which can be controlled as desired to regulate the period of wiper operation after the completion of liquid delivery. When sufficient liquid has escaped from chamber 81 to allow conical valve 69 to reseat, the supply of compressed air to the pump and coupler is discontinued and they are vented to atmosphere by way of passage 77, the space between rod 87 and its base 88, the top part of chamber 81 and vent hole 89. The pump draws in a fresh charge of liquid and the motor either ceases to operate, or, if it had been operating previously at a speed controlled by knob 38, returns to its former speed of operation.