GB951798A - Improvements in brake-operating mechanism for road vehicles - Google Patents

Abstract

951,798. Trailer brakes. CHARLES PITT (BARTON STACEY) Ltd. Dec. 21, 1961 [Dec. 23, 1960; Aug. 9, 1961], Nos. 44328/60 and 28769/61. Heading F2E. [Also in Division B7] In a trailer having steerable front wheels, wheel brakes and a draw bar, the latter is mounted for swinging movement about vertical and horizontal axes and is connected to a brake operating device so formed as to cause the brakes to be applied at zones which are spaced apart about the zone of normal vertical swinging movement of the draw bar when coupled to a towing vehicle whereby the brakes can be operated by vertically swinging the draw bar when uncoupled. As shown movement of the draw bar 3 about a vertical pivot 6 is used to apply a steering action on the forward wheels 2 by connecting the steering arms 8 to the rear end of the draw bar through transmission rods 9. The draw bar is also pivoted about the horizontal pivot 7 and carries coaxially therewith a cam 10 engaged by a follower 11 at the end of a pivoted - lever 12. The end of the latter abuts a rod 14 which is free to slide in a bush 15 constituting part of the vertical pivot 6. The lower end of rod 14 abuts a spring biased pivoted lever 16 which is coupled to the rear wheel brakes, and if they are fitted, to the front wheel brakes. The peripheral form of the cam 10 is such that movement of the draw bar through the neutral angle extending from 30 degrees to 90 degrees (see Fig. 4) does not apply the brakes. The operating zone during which the brakes are increasingly applied extends through the angle 0 degrees to 30 degrees and again through 90 degrees to 100 degrees i.e. when the draw bar is swung above or below its normal setting. The brakes are fully applied when the draw bar swings through the angle 340 degrees to 360 degrees and again when the swing is through 100 degrees to 103 degrees. In another embodiment the draw bar is formed longitudinally in two parts, the first part is mounted about the horizontal pivot on a forward extension of the trailer chassis and the second part is longitudinally movable with respect to the first against the force of a compression spring to provide " over-run " braking. The cam 10 is carried on the end of the second part and is rotatable about lateral pins which are mounted to slide in longitudinal guides formed in blocks secured to the first part about the horizontal pivot which is formed by stub pivots in horizontal alignment.