GB811505A - Automatic adjusting device, particularly for brakes and clutches - Google Patents

Abstract

811,505. Automatic adjusting devices for brakes. DUNLOP RUBBER CO. Ltd. Aug. 13, 1956 [Aug. 20,1955], No. 24046/55. Class 103 (1). [Also in Group XXIV] In an automatic adjusting device for a brake or clutch, a die is associated with one of the two relatively movable members of the brake or clutch and a ductile metallic element associated with the other of the relatively movable members is provided with a smaller diameter portion passing through the die whereby the element is progressively drawn through the die as wear of the mechanism takes place. In the embodiment illustrated an automatic adjusting device is associated with an aircraft multi-disc brake such that a ductile wire element 21 provided with a small-diameter portion 22 sliding in an orifice 20 of a die 19 is secured to the outer axially movable pressure plate 5 at 25. The die 19 is housed in a bush 10 slidably mounted against force of spring 12 in cavity 17 in rigid torque plate 3 of the brake. Clearance 15 denotes the desired combined clearance between the friction pads 4 and discs 1 and 2 when the brake is idle. In operation, when the brake is operated by pressurizing the hydraulic piston and cylinder mechanism (not shown) the pressure plate 5 is moved to effect frictional engagement between the discs 1, 2 and the friction pads 4, and the movement of the pressure plate 5 acting through the wire element 21 and the die 19, moves the bush 10 in the same direction against its associated spring 12 until the brake is fully engaged or until the end 16 of the bush bottoms on the base 8 of the recess 7 in the torque plate 3. If the bush bottoms in the recess 7 before the brake is fully applied due for example to wear of the friction pads, then the operating pressure will draw the wire element 21 through the die 19 to lengthen the smaller diameter portion 22 of the element 21 to an extent sufficient to allow the brake to be fully applied. On removing the braking pressure the spring 12 moves the bush 10 back to its original position in the recess 7 wherein the flange 11 abuts the spring clip 13 and in this position the other end of the bush 10 is spaced a predetermined distance 15 from the base 8 of the recess. The wire element 21, now slightly lengthened to compensate for wear of the friction pad 4, draws the pressure plate 5 the predetermined distance away from the discs 1, 2 to effect a constant running clearance between the discs and the pads.