GB606342A - Improvements in or relating to brakes - Google Patents

Abstract

606,342. Drum brakes. BENDIX AVIATION CORPORATION. March 20, 1945, No. 7042. Convention date, March 20, 1944. [Class 103 (i)] The torque-reaction member of a drum brake comprises a pair of platelike members having the central portions abutting on each other and secured to a fixed part and having radial arms offset axially from the central portions and disposed in opposite pairs between which the shoe actuating and anchoring means may be secured. The plates may be used for different kinds of drum brakes having internal shoes and of actuators and anchoring means. Figs. 1, 2, 4 show a brake of the kind in which each shoe 22, 24 of T-cross-section anchors at one end or the other-according to the direction of rotation of the drum 26. The torque member comprises a pair of plate-like members 34, 36 riveted at 38 to a flange on a vehicle axle casing 40 and having pairs of axially offset arms 46, 48 between which hydranlic cylinders 28 are mounted by means of cylindrical bosses 68. Turning movement of the cylinders between the arms is prevented by engagement of ribs 72 on the arms with depressions in the cylinders. The shoes are guided by the contact of other pairs of arms 50, 52, 54, 58, with the shoe webs 78. The shoes anchor through the pistons which in the inner position abut each on an annular flange formed inside the cylinder. The release springs 80 are hooked at one end to the plate 34 or 36, Fig. 4, and the other end 84 extends through the shoe-web 78 and engages a projection 88 on the shoe flange. Each shoe is provided at one end with an adjuster such as described in Specification 605,939 and comprising a pair of polygonal plates 100 disposed on either side of the shoe web and connected by a short tubular shaft 104 which seats in a notch in the end of the shoe' web. The plates abut at the edges on the pistons and are turned to effect an adjustment.' According to Figs. 7, 8, one shoe applies pressure to the other, one shoe or the other anchoring on the cylinder 30 which is constructed and mounted as are the cylinders 28, Figs. 1, 2. The shoes are connected by an H-section link 108, the ends of which are forked, as shown at 110, 112, 122, in planes parallel and at right angles to the torque member 34, 36 so as to receive the shoe web 78 and the stub shafts 120 of an adjuster comprising a pair of polygonal plates 102a, the edges of which bear at 118 on the link while the web 78 bears on the part between the plates. The shoe 22 is adjustable also by an eccentric 124, the shaft of which is mounted in the plates. In order that the plug by which the bleeder passage of the cylinder 30 is closed may be accessible from the same side of the torque member as the supply connection to the cylinder, a pipe 136 connects the bleeder port in the cylinder to a tubular part 138 which extends through the plates 34, 36 and receives the usual screw plug such as 93, Fig. 2. Figs. 12, 14 show a torque member 34, 36 of the same construction as in Figs. 1, 7 used with a brake in which the shoes 22, 24 are expanded by a single hydraulic cylinder 30 and anchor at the other ends on a fixed member which is of the cross-section shown in Fig. 14 and has cylindrical bosses 146 by which it can be mounted in the same manner as the cylinders 30, 28. Adjusters 100 similar to those of Fig. 1 are provided. Brakes are also shown of the same kind as those shown in Figs. 1, 7, 12, but in which the hydraulic cylinders are replaced by mechanical actuators each comprising a pair of plungers 156, Fig. 15, slidable in a cylinder 150 provided with cylindrical bosses similar to the bosses 68, Fig. 2, whereby it may be mounted between a pair of arms 48 of the torque member 34, 36. The plungers are operated by a floating cam 162 carried by a shaft 166 and may anchor at 160 on a reduced part of the cylinder. Where two actuators are provided as in Fig. 1, arms on the two shafts 166 may be interconnected to effect simultaneous actuation.