GB604483A - Improvements relating to vehicle wind screen wipers - Google Patents

Abstract

604,483. Windscreen wipers. LUCAS, Ltd., J., HAWKESWOOD, R. W., and PURDEN, R. H. Nov. 26, 1945, Nos. 31799/45 and 8141/46. [Class 138 (i)] An oscillatory vehicle windscreen wiper comprises a main arm, a sub-arm attached at one end thereto and having a limited range of pivotal movement relative thereto, and in the plane of movement thereof, and adapted to be attached at the other end to the wiper blade. In one form, Figs. 2 and 3, the main arm a and sub-arm e are loosely pivoted together by a pin d so that the arm e can move angularly relative to the arm a to an extent limited by stops j formed in a protective metal piece 7c secured to the arm a, and can also pivot slightly in a plane at right-angles to the screen. Two projections m of a metal strip n on the arm e extend towards the main arm, one projection m engaging between a stop and an abutment o of a metal piece p on the arm a, so that the arms are substantially locked together. In operation, at the beginning of a stroke, the drag of the screen on the blade causes the arm e to pivot in a plane normal to the screen, releasing the projection m from the abutment o, and then causes the arm e to pivot about the pin d until the other projection m engages between the other abutment o and stop j, locking the arms in the opposite position. In a second form, Figs. 5 and 6, the arms a, e are locked by one of two projections t in a plate r pivoted at r<SP>1</SP> to the arm a engaging one of two apertures u in the arm e. Towards the end of each stroke, one of two bent-over portions x of a lever v pivoted at w to the arm a abuts a fixed stop, whereby a bifurcated portion of the lever v embracing the plate r pivots the plate r to release the arm e, an over-centre spring s then tending to continue the pivoting movement,.until on reversal of the stroke the arm e is caused by the drag to pivot about the arm a until the other projection t engages the other aperture u to lock the arms in the alternative position. In a third form, Fig. 7, the arm e has a metal piece y with in-turned flat edges z, one of which engages the flat head 4 of a locking member 2 slidably attached to the arm a and having one end abutting a stationary cam 5. During a part of each stroke, the cam 5 allows the member 2 to be retracted under the action of a spring 6, whereby the arm e is released and pivots relative to the arm a until the member 2 engages the other edge z, locking the arms in the alternative position. All of the forms described result in the blade resting flat against the edge of the screen when the wiper is in a limit position, owing to the inclination between the arms a, e, while preventing undesirable or premature pivoting between the arms. Specification 578,353 is referred to.