GB1016564A - Improvements in and relating to automatic adjusting devices for disc brakes - Google Patents

Abstract

1,016,564. Disc brakes. AUTOMOTIVE PRODUCTS CO. Ltd. Nov. 1, 1963 [Nov. 1, 1962], No. 41436/62. Headings F2E and F2F. An automatic adjuster for a disc brake is incorporated in an hydraulic applying cylinder 1 and comprises a pair of telescoping members 8, 9 in screw-threaded engagement, interposed between a sliding plunger 3 of a hand brake mechanism (not shown) and the rear face of a hollow piston 2, and pawl-and-ratchet mechanism for adjusting the members 8, 9 on operation of the hand brake mechanism in the brakeapplying direction, the mechanism including resilient means whereby relative movement of the pawl and ratchet members of the mechanism occurs only when a predetermined applying movement is exceeded, and whereby further applying movement does not cause further operation of the mechanism. In one embodiment, Figs. 2 and 3, the resilient means is a torque spring 13 wound on an anchor-pin 14, one end 12 of spring 13 forming a pawl to co-operate with a ratchet wheel 11 on the tubular member 8 which abuts a flange 7 of the plunger 3. The member 9 is telescopically received in the member 8 and secured to a plate 10 mounted within the piston. A lever 18 is pivoted at 19 and engages by an abutment 20 the opposite end 17 of the torque spring, and by an abutment 21 the end formed as a pawl. In operation, movement of the plunger in the brake-applying direction causes flange 7 to abut the lever 18 which pivots to cause corresponding movement of the torque spring. The end 12 of the torque spring at first remains stationary owing to flowing, the ratchet wheel being held by a retaining pawl 23. When the resistance of the latter is overcome the ratchet wheel is moved to effect adjustment until the retaining pawl again arrests it and further movement in the brake application direction again merely flexes the pawl. In a second embodiment, Figs. 4 and 5, the pawl is formed by a lever 25 but the latter is pivoted on one limb 26 of a resilient U-shaped member 27 which is anchored non-rotatably by its other limb 29 to a bracket 32. Movement of the ratchet wheel is resisted by a resilient friction pawl 35, so that when the lever pivots consequent upon operation of the plunger 3 the member 27 fluxes and prevents movement of the pawl until a given movement has been exceeded, and also prevents further movement of the pawl after an adjustment, as in the previous embodiment.