Patent GB-944176-A (GB)
Title: Automatic brake adjuster
IPC: F16D65/54
Filed: 1960-09-21
Abstract: 944,176. Automatic brake adjusting devices. BENDIX CORPORATION. Sept. 21, 1960 [Oct. 1, 1959], No. 32455/60. Heading F2E. In an automatic adjusting device for brakes an elongated member is attached to a movable brake member and driven thereby over the whole stroke of the brake member during brake application, means connect the elongated member to a fixed part of the brake and permit movement of the elongated member and brake member in the brake applying direction and preventing such movement beyond a predetermined distance in the reverse direction under the action of a return spring compressed between an abutment of the elongated member and the fixed part of the brake, the means comprising members surrounding the elongated member to establish a lost motion connection between the elongated member and the fixed part of the brake. In the embodiment shown in Fig. 2, a multi-plate disc brake is applied by a series of hydraulic piston and cylinder devices (not shown) having situated therebetween a series of automatic adjusting devices 30. Each device 30 consists of a stem 32 forming an elongated member secured at one end 34 to an axially movable pressure plate 20. A sleeve 40 surrounds the stem 32, a spring 60 surrounds the sleeve 40 between a nut 38, screwed to the other end of the stem 32 and forming an abutment member of the stem, and a member 58 secured to stationary carrier plate 26. A friction block 46 engages frictionally the outer surface of the sleeve 40 and the distance " D " between an abutment 56 formed on the member 58 and the friction block 46 determines the amount of running clearance which is maintained by the brake adjuster between the rotors and stators. When the brake operation is initiated the friction block 46 is in engagement with the stop 56 and the fluid actuators bias the pressure plate 20 towards the reaction member 18 of the brake, frictionally engaging the stack 10 of interleaved rotors 14 and stators 12 which are splined for axial movement. The friction block 46 moves with the sleeve 40 through the distance " D " representing the adjusted running clearance in the brake and then engages the shoulder 55 of the carrier plate 26 to prevent further movement of the friction block with the sleeve 40. As wear occurs in the brake, the pressure plate 20 will continue to move toward the backing plate pulling the stem 32 and sleeve 40 through friction block 46, the sleeve 40 being slipped through the block 46 against its frictional resistance. When the fluid motors are released the spring 60 pulls the stem 32, sleeve 40 and attached pressure plate retractively through the distance " D " until the friction block 46 engages stop 56, the pressure plate being retracted the distance " D " to maintain the brake clearance. When the friction block 46 engages the stop 56 retractile movement of the pressure plate 20 is terminated since the spring 60 is not sufficiently strong to overcome the frictional resistance between friction block 46 and the sleeve 40. Alternative arrangements are disclosed in the Specification including one in which the friction block 46 is replaced by a spring loaded pawl arrangement which engages with serrations on the stem 32. Reference has been directed by the Comptroller to Specification 785,773.