Patent GB-1087988-A (GB)
Title: Improvements in and relating to disc brakes
Inventor: CHOUINGS LESLIE CYRIL
IPC: F16D55/02
Filed: 1965-03-04
Abstract: 1,087,988. Disc brakes. AUTOMOTIVE PRODUCTS CO. Ltd. March 31, 1966 [March 4, 1965], No. 9299/65. Heading F2E. In a disc brake having at least two annular brake discs 1, 2 arranged in spaced coaxial arrangement, one brake disc 1 is fixed axially whereas the other brake disc 2 is movable axially, brake pads 19, 20, 21 and 18 being provided on opposite sides of each brake disc and a first movable member 23 is operatively associated with the brake pad or pads 19 on one side of the brake disc 2 and a second movable member 24 is operatively associated with the brake pad or pads 18 on one side of the axially fixed brake disc 1 such that when brake operating means 34 is actuated the first and second movable members 23, 24 are moved towards one another to engage the friction pads with the brake discs. As shown in Fig. 1, operation of a fluid pressure actuated mechanism 34 causes rotation of a housing 28 and an inner ring 36 attached thereto rotates relatively to an outer ring 37. This relative rotation results in a camming action due to the ball and ramp mechanism 38, 39, 40 to urge the rings 36, 37 in opposite directions, the outer ring 37 moving the second movable member 24 in an outward direction to press the brake pads 18 into frictional contact with the axially fixed brake disc 1. Simultaneously a rod 25 which is in screwed connection with a bush 43 located in the housing 28, moves in an inward direction to engage the first movable member 23 to bring the brake pads 19 on the outward side of the axially movable brake disc 2 into contact therewith to displace the disc 2 towards the axially fixed disc 1 so that the brake pads 20, 21 between the brake disc are each brought into contact with the appropriate faces of the brake discs. Within the housing 28 is provided means for affecting automatic adjustment to compensate for wear on the friction pads. This automatic adjusting mechanism comprises the bush 43 adapted to be rotated through a oneway clutch device which is interposed between the housing 28 carried by a shaft 29 and the bush 43, a thrust bearing 45 being interposed between the clutch and the inner ring 36. The one-way clutch comprises a clutch ring 46 which is arranged concentrically with the bush 43. The periphery of the clutch ring 46 is provided at angularly spaced points with flats 47 each of which forms a gap of gradually decreasing width with the surrounding wall of the housing 28 and a roller 48 being accommodated in each gap. When adjustment is required, the rollers 48 will wedge in the gaps and provide a driving connection between the housing 28 and the bush 43; rotation of the bush 43 causes displacement of the rod 25 corresponding to the wear of the friction pads. An over-ride device is provided between the one-way clutch and the bush. The over-ride device comprises arcuate slots 49 found in the periphery of a flange 42 of the bush 43, each of which accommodates a lug 50 extending laterally from one face of the clutch ring 46. The circumferential length of each arcuate slot 49 is greater than the width of each lug 50 and a spring 51 is interposed between each lug and one end of its slot to hold the lugs against one end of the slot. The brake pads are mounted on backing plates which are located on pins (57) (Fig. 6, not shown) and are further located on the thrust plates 22 by means of spring clips (59). The brake pads are adapted to be removed radially outwardly by the provision of opening 60 and appropriate positions in the housing 3. The braking torque load transmitted from the brake discs is taken by two cross-bars (52) (Fig. 4, not shown) each of which is supported at opposite ends by the movable members 23, 24.