Patent GB-546036-A (GB)
Title: Improvements in or relating to brakes
IPC: F16D65/14
Filed: 1940-12-23
Abstract: 546,036. Brakes. BENDIX AVIATION CORPORATION. Dec. 23, 1940, No. 18037. Convention date, Dec. 26, 1939. [Class 103 (i)] A brake comprising a pair of shoes that are individually shiftable to anchor at one end or the other according to the direction of drum rotation, is applied by a fluid-pressure cylinder that acts directly on one end of one shoe and on a lever that is pivoted to the adjacent end of the other shoe and is connected to a floating lever adapted to separate the other ends of the shoes so that both pairs of adjacent shoe ends are separated. The shoes anchor at one end through a manually operated adjusting device on the cylinder which may have a dash-pot action to cushion the movement of the shoes to the anchor. Automatic adjusting means comprising a member movably carried by each shoe and adapted to contact the drum may also be provided. A pair of levers 32 pivoted one on each side of the shoe 14 are connected by a thrust link 30 with the corresponding arms of a floating lever 24 the arms of which are notched at 26 to embrace the anchor post 20 and are united and at this end by parts 28 that engage the shoe ends. A plunger 34 bears on one piston 46 of a cylinder 44 and on the levers 32 and is slotted to pass through the end of a screwed member 40 on either side of the end part 38 of that member and on either side of the shoe web. The plunger 56 of the other piston 54 extends through a screwed member 60 which is slotted to receive the web of the shoe 16. The shoes anchor on the cylinder 44 through the members 40, 60 and caps 42, 62 which are rotatable to adjust the members 40, 60 by gear wheels on the back plate 12, and are locked by engagement of a spring 68 with the toothed edges thereof. When the brake is applied with the drum rotating counter-clockwise the shoes 14, 16 anchor respectively on the post 20 and part 60. The release spring 172 may be stronger than the release spring 170 so that neither shoe initially leaves its anchor and to cushion the shock due to the change of anchorage with an application when the drum is reversely rotating, the cylinder has a partition 116 which leaves only a restricted passage 118 between the cylinder chambers thus providing a dash-pot action. The brake may alternatively be applied by a lever 78 connected to thrust members 80, 82 that engage the respective shoe webs and guided by brackets 84, 86 on the back plates. Automatic adjusting means comprises a block 92 of hard material slidable in guides 94 on the shoe and extending through the friction lining to contact the drum when the shoe is applied. A disc 106 rotatable in the shoe web carries on a pin 100 a cam block 98 slidable in a cam slot 96 formed in the block 92. Movement of the block 92 on the shoe as the lining 18 wears thus turns the disc and an arm 108 secured to it, the release position of the shoe being determined by the abutment of the arm with a stop comprising a roller 110 carried by an adjustable eccentric 112 mounted on the back plate. In a modified construction; the automatic adjusting means and the cylinder partition 116 are omitted and the release springs 170, 172 are replaced by a single spring extending between the shoes and which is lighter than the lower release spring 22 so'that the upper shoe ends are first moved apart in an application.