GB1360598A - Dual system opposed cylinder calipers for disc brakes - Google Patents

Abstract

1360598 Bleeding arrangements; slave cyliriders; dual systems; disc brakes GIRLING Ltd 1 Sept 1971 [2 Sept 1970] 41889/70 Headings F2E and F2F A caliper 20 of a dual circuit spot-type disc brake incorporates pairs of opposed cylinders 30, 31 and 34, 35 for actuation by the respective circuits and each pair of cylinders 30, 31 (34, 35) is provided with a single, feed port 36 (43) and a single bleed port 41 (51) and the feed ports 36, 41 and the bleed ports 43, 51 are all provided on the same side of the caliper 20. As seen in Fig. 1 the caliper 20 is positioned approximately at the same level as the axis of a disc 36<SP>1</SP> and includes an inboard limb 21 and an outboard limb 22 bolted together and having upper and lower joint interfaces 39, 46 respectively and with a central open portion 25. The ports are all provided in the inboard limb 21 since access to the outboard limb 22 is only possible after removal of a wheel. The first feed port 36 communicates with the lower part of the cylinder 30 and inclined passages 37, 38 in the caliper limbs 21, 22 communicate with the upper parts of the cylinders 30, 31 and communicate with one another at the interface 39: a bleed passage 40 communicates with these passages 37, 38 and leads to the bleed port 41. The passage 38 can be divided into two channels. The second feed port 43 communicates via passages 44, 45 with the lower part of the outboard cylinder 35, and a passage 42 including portions 47, 48, 49, 50 communicate the upper part of cylinder 35 with the lower part of cylinder 34 and bleed port 51 is connected to the upper port of cylinder 34. In alternative arrangements the second feed port 43 communicates with the lower part of the cylinder-34 and the upper part of the cylinder 34 is connected to the lower part of cylinder 35 via the passage 45 or via a passage which extends above the upper cylinders 30, 31. Figs. 2-4 and Figs. 5-10 illustrate two other arrangements. As seen in Fig. 2 the bleed ports 41, 51 include bleed screws 41a, 51a; it is stated that the passages are sealed at their interfaces by sealing rings (e.g. 49a, see Fig. 4, not shown). The passageway 50 includes an inclined portion 50a and an upward portion 50b. As shown in Fig. 5 the passage 42, linking cylinders 35, 34 includes, an external pipe 58.