GB1490514A - Brake adjusting pins - Google Patents

Abstract

1490514 Slack adjusters; mounting cams on pins S ARTHUR and P W JOHNSON 18 Oct 1974 [2 Aug 1973] 36718/73 Divided out of 1386078 Headings F2E and F2V A brake adjusting pin 14 for an internal expanding vehicle drum brake assembly comprises an outer end portion which includes an abutment 16 and a tool engaging part 18, an intermediate cylindrical bearing portion 20 for rotatably mounting the pin 14 in a bearing hole 12 in a back plate 10 and a generally cylindrical cam engaging portion 24 whose circumferential surface is formed with a self-cutting or selfdeforming formation (e.g. teeth 28) capable of cutting or deforming a bore of a cam 32 in a keying manner so that the pin 14 and the cam 32 are keyed together against relative rotation, the pin 14 also having a screw-threaded bore 38 in its inner end portion 35 to receive a bolt 40, rotation of which advances the cam 32 longitudinally of the pin 14 into engagement with the self-cutting or self-deforming formation thereof. As shown in Fig. 1, the teeth 28 of which there are twenty-four are of V-shaped crosssection and extend parallel with the longitudinal axis A-A of the pin 14, although they could be disposed in spiral relation to this axis. The cam 32 includes a part formed with a peripheral cam edge 44 of spiral formation formed with notches so as to have a snap-action engagement with a pin 46 extending from the web 48, and a cylindrical metal sleeve part 50 wleded to part 44. To assemble the illustrated structure, a spring 56 is pushed on to the portion 20 of pin 14 and the inner end portion 35 is inserted into hole 12 from the outside thereof. A resilient circlip 36 is then sprung into a groove 34 formed in portion 35, and the outer chamfered end of sleeve part 50 is presented towards the inner end of pin 14 and whilst held manually in this position the bolt 40 is engaged with bore 38 and is rotated relative to the pin 14 by engaging the bolt head and the part 18 of pin 14 with spanners so that a washer 42 mounted on the bolt 40 moves the cam 32 longitudinally of the pin 14. During this movement the sleeve part 50 first moves over the circlip 36 and thereafter engages the deforming teeth 28 to key the pin 14 and the cam 32 together. When the circlip 36 springs outwardly to engage a shoulder 52 in the bore of sleeve part 50, the relative rotation of the pin 14 and the bolt 40 is stopped and the bolt 40 including the washer 42 is removed. In the embodiment of Figs. 2, 3 an abutment shoulder 26 is provided between the toothed cam engaging portion 24 and the bearing portion 20 for engagement by the cam 32. A metal spacer sleeve 50 has an easy-fit engagement with the bearing portion 20. In this embodiment the bolt 40 is of the self-locking type and is allowed to remain engaged with the pin 14 after assembling the illustrated structure.