| 摘要 |
1283868 Disc brakes; automatic adjusters BENDIX CORP 25 Sept 1970 [3 Oot 1969] 45743/70 Heading F2E A spot-type disc brake assembly 10 wherein a brake shoe 26 is applied by a piston 36 slidable in a chamber 34 of a housing 32 and a brake shoe 24 is applied by reaction via a caliper 12, incorporates an automatic adjuster mechanism 46 within the housing 32 which mechanism 46 comprises a nut 48 threaded on to a post portion 50 of an elongated member 52, the nut 48 being threadably movable along the post portion 50 to adjust for brake pad wear but the elongated member 52 having a surface 78 acted on by hydraulic pressure such that at pressures above a predetermined value the mechanism 46 is slidable in the chamber 34 to prevent adjusting action of the mechanism 46 at pressures above this value. This ensures that over adjustment of the mechanism 46 does not occur during a " panic stop." As shown, the piston 36 has a washer 58 which via an anti-friction bearing 62 acts to turn the nut 48 on the post portion 50 when the piston 36 has moved in actuation through a distance indicative of brake pad wear. During return movement of the piston 36 the threads of the nut 48 and the post portion 50, which threads have a helix angle of substantially 18-21 degrees, look to prevent backward movement of the nut 46 and a shoulder 64 on the piston 36 comes into abutment with the nut 46 to halt the piston 36. Hydraulic pressure is communicated to the surface 78 by a channel 80, but during normal application a spring 84 prevents movement of the elongated member 52. A mechanical actuator 92 is incorporated in the disc brake which actuator 92 comprises a handle 94 and a toggle 96 movable to cause movement of the member 52 and the piston 36. |
