Patent GB-713425-A (GB)
Title: Improvements in or relating to windscreen wipers
IPC: B60S1/42
Filed: 1950-07-28
Abstract: 713,425. Windscreen cleaners. O'SHEI, W. E. Aug. 10, 1951 [July 28, 1950], No. 18975/50. Class 138 (1) A windscreen wiper of the type wherein the arc of wiping of the blade may be increased at the end of its stroke, comprises means pivotally connecting the blade to the 'wiper arm for angular movement relative to the radial direction of the arm, resilient means for normally retaining the blade and arm in a predetermined relative angular relationship, and stop means for restraining or preventing angular movement of the blade from its normal position relative to the arm in a direction which it tends to turn by reason of the drag between the outer end of the blade and the windscreen during movement of the blade across the screen. The wiper arm 11, Fig. 1, mounted for rotation about an axis below the bottom of the windscreen carries a die-cast housing 12 pivotally connected to a rod 7 positioned, between apertured ears 1 and 3 upstanding from a member 16 on the blade 2, by means of a collar 7a of the rod and a helical compression spring 6. The ear 1 is fixed relative to the blade but the ear 3 is pivotally connected at 5 by a limb 4 to the blade so as to be movable transversely of the ear 1 and upwardly from the back of the blade. The housing side walls 19 and 20, Fig. 5, straddle the limb 4 of the ear 3 so as to form stop members, normally to prevent the ear 3 from being twisted relative to the ear 1. Owing to the rocking of the blade into a trailing position as the blade moves over the screen, the leading edges of the member 4 and side wall 20 .are separated as the blade moves to the right of Fig. 6. The other edge of the member 4, however, abuts the edge of the wall 19. The separation between the leading edge 4 and the wall 20 will allow of relative twisting between the housing 12 and the ear 1, Fig. 3, to permit parking of the blade along the bottom edge of the screen. However, the abutting of the rear edge of the member 4 and the wall 19 will prevent twisting of the housing in the opposite direction. Twisting of the blade relative to the arm due to drag action of the upper end of the blade on the screen is therefore prevented. When the blade moves in the opposite direction over the screen it rocks to an opposite trailing position to that shown in Fig. 6 so that the side wall 19 is then separated from the leading edge of the member 4 whilst the rear edge of the member 4 abuts the side wall 20. Twisting action of the blade relative to the arm during parking of the blade is again facilitated but the opposite twisting action due to drag action is again prevented. In a modification in which the arm is reversed in position to that shown in Fig. 1, so that the ear 3 is nearer the axis of rotation of the arm, the ear 3 and its limb 4 and the housing 12 are caused to pivot upwardly from the back of the blade as the blade is arrested by the screen frame, due to the continued movement of the arm. The housing rises more than the member 4 so that the wall 19 or 20 as the case may be clears the corresponding edge of the member 4. If desired the member 4 may have a protuberance engaging in a recess in the back of the member 16 so as to prevent twisting of the blade during its normal movement over the screen. The invention may be applied to the constructions described in Specifications 657,822 and 712,603, which are referred to. Specification 523,177 also is referred to. Reference has been directed by the Comptroller to Specification 685,290.