Patent GB-1252245-A (GB)
IPC: F16D55/226
Filed: 1970-05-07
Abstract: 1,252,245. Spot-type disc brakes; retaining or torque-taking parts. AISIN SEIKI K.K. 7 May, 1970 [10 May, 1969; 13 May, 1969], No. 22022/70. Heading F2E. A spot-type disc brake comprises pins 40, 41 for retaining friction pads, a transfer plate 22 for transferring a braking movement from brakeactuating means 13 over a brake disc 10 to a friction pad 25, and rails 26, 27, extending from the brake-actuating means 13 over the brake disc for counteracting torque from the friction pads, each rail 26, 27, comprising an end portion, remote from the brake-actuating means, that overlies an inner edge portion of the upper face of the reaction transfer plate. As shown in Fig. 2, a brake disc 10 is bolted to a wheel hub 12, while projecting bosses 15 on a brake-actuating mechanism 13 secure the mechanism to a fixed part 14. The mechanism incorporates an open-ended piston housing 16 in which slide two pistons 17, 18 which may be urged apart by hydraulic fluid. Piston 18 engages directly the backing plate 19 of brake pad 20, while piston 17 engages one inner edge 21 of a reaction transfer plate 22, Fig. 1, for transferring its movement to the other brake pad 25 via its backing plate 24. The part of the reaction transfer plate 22 remote from the brake-actuating mechanism 13 is supported by pins 40, 41, Fig. 3, which pass through holes in portion 42 of a steel bracket 43 welded to the plate 22 and which are retained by split pins 48, 49, Figs. 1 and 2. The pins, 40, 41, in turn, are slidably supported in openings 44, 45, in the piston housing 16. Slidably mounted on the pins 40, 41, are the backing plates 19, 24. Rails 26, 27, Fig. 3, extend from the brake-actuating mechanism over the disc 10 for counteracting torque from the friction pads. The sides of backing plate 19 engage the inner guide surfaces 28a, 30a, respectively, of first portions 28, 30, respectively, of rails 26, 27, and shoulders 47 of the backing plate engage the tops of these portions, while the shoulders 46, slots 34 and parts 35 of backing plate 24 engage respectively the tops, inner guide surfaces 29a, 31a and the undersides of second portions 29, 31 of the rails 26, 27. Slots 32, 33, in rails 26, 27 accommodate disc 10. The top of edge 23 of the reaction transfer plate 22, Fig. 3, engages the undersides of the second portions 29, 31. In the modification of Fig. 6, the reaction transfer plate is supported, not directly by the pins 40<SP>1</SP>, 411, but by the engagement of parts of its inner edge 23 with slots 34<SP>1</SP> in backing plate 24. Also, pins 40<SP>1</SP>, 41<SP>1</SP>, are in this case fixed-at their inner ends in the piston housing 16, where they are secured by split pins, (not shown), and at their outer ends in the second portions 29, 31, of the rails 26, 27. Also, the tops of the rails 26, 27 are not used, and though the side edges of backing plate 19 engage the insides of the first portions of the rails, there are clearances between the side edges of backing plate 24 and the surfaces 29a, 31a, of the second portions 29, 31 of the rails. In this modification the brake torque acting on pad 25 is said to be transmitted via its backing plate and the transfer plate 22 to a steel plate 43<SP>1</SP> welded to the transfer plate, and thence to one or other of the surfaces 29a and 31a of the rails with which the side edges of plate 431 are in contact.