GB258139A - Improvements in or relating to windscreen wipers - Google Patents

Abstract

258,139. Melmore, W. M. Dec. 24, 1925. Windows and the like, cleaning. - Windscreen wipers are provided with a delay action device comprising a dashpot or the like associated with the wiper-operating means, so that repeated operation of the wiper is delayed for a predetermined interval of time. Specification 230,220 is referred to in which an electric solenoid and plunger are provided with automatic means for intermittent operation. The present invention is not necessarily confined to the solenoid and plunger type. A plunger 1, Fig. 1, actuating a wiper 2 has a rod 3 provided with a cup leather 4 reciprocating into a cylinder 5 open at one end, and with a finely adjustable air inlet cap 6. Air leakage occurs past screw threads on a rod 7 and can be adjusted by rotation of the cap 6. A spring 8 tends to withdraw the rod 3 from the cylinder. An abutment 9 on the rod 3 contacts with a pivoted switch arm 10 to engage a movable contact 12 on the arm with a fixed contact stud 13 or two dummy contacts 14, 15. The cylinder 5 is formed in an ebonite block 16 which is extended forwards to serve as a mount for the studs 13 &c. A spring presses the switch arm 10 into electrical contact withe the studs 13 &c. On the rod 3 is slidably mounted a member 18, Fig. 2, with a contact end 19 to fit into the cup leather 4 while the other end 20 acts as an abutment on which the member 9 can strike. A roller 21 carried by the arm 10 engages between the ends 19, 20 of the member 18. Current passes through the solenoid 22 so as to operate the plunger 1 sharply inwards, and continues through the switch 10 and stud 13. The cup leather 4 is forced into the cylinder 5 against the spring 8 and the member 9 strikes the member 18 moving the switch arm 10 to cut off current. The cup leather 4, rod 3, &c., returns slowly against the action of spring 8 as air leaks into the cylinder, but when the cup leather 4 is free of the cylinder it moves quickly to strike the member 18 switching the arm 10 into contact with the live stud 13. To retain the wiper out of use, a spring 29 is allowed to engage a notch 30 in the plunger 1 and hold it. The plunger 1 is, when in operation, prevented from sliding so far by a movable cam 24 provided with a handle 27. Instead of electrical control by the switch 10, valve control means might be substituted for a power operated wiper.