GB1256897A - - Google Patents

Abstract

1,256,897. Disc brakes. GIRLING Ltd. 24 Sept., 1969 [2 Oct., 1968], No. 46656/68. Heading F2E. A yoke for use in a disc brake of the kind in which an hydraulic actuator is adapted to apply a friction pad assembly 25, 26 directly to an adjacent face of a rotatable disc 11, and to apply a friction pad assembly 28, 29 to the opposite face of the disc through a yoke 14 mounted on or in a stationary member 10 for sliding movement parallel to the axis of the disc, the yoke comprises a one-piece member adapted to fit over the member 10 and a portion of the periphery of the disc and provided with a pair of spaced, flat parallel guiding surfaces 19 of substantial radial depth for direct operative engagement with complementary flat guiding surfaces 20 on opposite sides of the member 10, the surfaces 19 on the yoke at least at one pair of corresponding ends leading into opposed bearing surfaces 21 for engagement with complementary shoulders 22 on the member 10. As shown, the surfaces 19 are formed on oppositely disposed lugs 18 and opposed adjacent faces of lugs 16, 17 provide parallel abutment faces 24 at right angles to the surfaces 19. The pad 25, and backing plate 26, is slidably guided by surfaces 27 on arms 23 and moved towards the disc by a piston 30 in an hydraulic cylinder 13 in the yoke and an opposed piston acts on the yoke through lug 17 to bring the pad 28 into engagement with the disc, the latter pad being secured to the lug 16 by removable pins 29a and the pad 25 being held against radial movement by a spigot 33 of the piston 30 engaged in an opening 32 in the plate 26. The piston 31 has a spigot 34 surrounded by a thrust face 35 engageable with the surface of the lug 17 and a resilient sleeve 34a of synthetic plastics surrounds the spigot. The yoke is resiliently urged into engagement with the shoulders 22 by a spring 36 acting between plates 39, 40 and surrounding a stud 37 secured in the member 10; alternatively, the stud is replaced by a headed stud and the spring acts between the base of the recess 38a and head of the stud, or a yoke is held in engagement with the shoulders 22 by a pair of tension springs positioned circumferentially at opposite ends of the brake. Wear resistant strips may be interposed between the surfaces 19 and 20. In a modification (a) the surfaces 19, Fig. 8 (not shown), on the member 10 lead into opposed, outwardly directed, aligned shoulders (45) which slidably engage edges (46) on the lowermost ends of the lugs 18 on the yoke, and the yoke 14 is urged into engagement with the shoulders by a spring plate (47) under the head of a bolt (48), which may comprise a bleed screw (51), Fig. 9 (not shown), for bleeding the hydraulic system, and (b) the means for resiliently urging the yoke 14 into engagement with the shoulders 22 is omitted and movement in the outward direction is prevented by the sliding engagement of bearing surfaces (60), Fig. 11 (not shown), of extensions (61) at the lower ends of the lugs 18 of the yoke with guiding surfaces (62) at the lower ends of the arms 23 of the member 10.