GB580588A - Improvements in or relating to brakes - Google Patents

Abstract

580,588. Brakes. BENDIX AVIATION CORPORATION. Oct. 27, 1944, No. 21013. Convention date, Jan. 20. [Class 103 (i)] In an internally expanding brake wherein the brake shoes abut on a common fixed anchor, the anchor has flat abutment surfaces which are substantially radial to the drum and the retracting spring is arranged between the anchor and the adjustable stops for the shoes. The spring may be arranged to keep the shoes in frictional contact with the back plate as well as to retract the shoes. In Fig. 1, the lower ends 20, 22 of the shoes 16, 18 contact with the flats on the anchor 24 which permit radial sliding of the shoe ends, and the shoes are spread by an hydraulic actuator. The shoes are each adjusted by a rotatable member 40 having an eccentric pin 48 in contact with the web of the shoe, the member being held in its position of adjustment by the friction of a spring washer. The shoes are retracted by springs 52, 38, the movement of the spring 38 about the adjuster 48 being greater than the movement of the spring 52. The shoes are maintained against displacement by the friction of the adjusters 48 and of the anchor, and by friction of the shoes against ledges 54 on the back plate, the shoes being held against the ledges by the spring 38 which is deflected under the extension 56 of the anchor-reinforcement plate secured to the back plate. The ends of the shoe webs are received in slotted heads 60 of inserts in the pistons 34, and anchor 24 has an enlarged head 64 which positions the other ends of the webs. Either the anchoring ends of the shoes or the sides of the anchor 24 may be slightly curved to permit slight rocking of the shoes. Two adjacent anchors, one for each shoe, may be provided. In Fig. 6, the anchorreinforcement plate 56a is shaped to provide a ramp for the parking-brake operating cable 66 which is connected to a lever 68 pivoted at 70 on the shoe 18, a strut 72 connecting the lever with the shoe 16. Each shoe is adjusted by a shaft 74 carrying a cam 78 in contact with the rim of the shoe, locking being effected by a washer 80 having radial springy arms 82. Each arm 82 has a detent and the back plate is provided with corresponding depressions into which the detents click. A hexagon head 76 is provided for the adjusting tool. In a modification, the shoes abut on the edges of the anchor-reinforcement plate which is spot welded to the back plate and is provided with ears to prevent lateral movement of the shoes. Specification 487,252 is referred to.