Patent GB-470644-A (GB)
Title: Improvements in or relating to brakes for automobiles
IPC: F16D51/50
Filed: 1936-02-18
Abstract: 470,644. Shoe brakes. BENDIX AVIATION CORPORATION. Feb. 18, 1936, Nos. 4882 and 4883. Convention dates, Feb. 18, 1935 and March 27, 1935. [Class 103 (i)] In a brake in which a brake shoe is caused by the drum rotation to apply pressure to a second shoe, part of the pressure exerted by the first shoe is taken by resilient means interposed between the shoe connecting means and the anchor plate so that only the remaining part of the pressure is transmitted to the second shoe. The resilient means may comprise a rubber block or a coil spring. In Fig. 1, the shoes 16, 18 bear on a metal bush 34 which surrounds a rubber block 36 through which passes a pin 38 secured to the back plate 12. The shoes are expanded by a pair of pistons 22 in a hydraulic cylinder 20. If the brake is applied, with the drum rotating counter-clockwise, the block 36 yields and part of the torque of the shoe 16 is transmitted to the pin 38 and part through the bush 34 to the shoe 18 which anchors through the piston on the end of the cylinder 20. If the drum is rotating in the reverse direction, part of the torque of shoe 18 is transmitted to shoe 16. Each piston is connected to the shoe through an adjusting device comprising a thrust member 24 seated in the piston, rotatable by a toothed wheel 30 and having a socket screwed on to a non-rotatable rod 28 engaging the shoe. A vertical plate with a pair of rubber blocks, one on either side of it, may be substituted for the single block and pin 38 or there may be a pair of bushes such as 34 connected by a bar with one shoe bearing on each bush. In Fig. 10, the bush 78 surrounding the rubber block 80 anchored on the pin 82, has threaded extensions 76 upon which and upon studs 72 engaging the shoe ends turn threaded sockets 74. The shoes 16, 18 are expanded by a floating lever 52 having projections 54 engaging the shoe ends and actuated by a lever 58 pivoted on the anchor 50 and engaging a projection 56 on the lever 52. In Fig. 13, the ends of the shoes 16, 18 engage threaded sockets 84 which receive threaded rods 86, 88. The rods have interfitting cylindrical heads 92 keyed together so that both of them may be turned by a toothed wheel 90 on one of them. A rubber bushing 94 is bonded to one of the cylindrical heads and to a fixed sleeve 96. In Fig. 16 rubber blocks 112 are bonded to a fixed member 114 and to a plate 110 which is engaged bv the shoe ends. In this arrangement and that of Fig. 13, the rubber blocks act in shear. In Fig. 19, right- and left-handed threaded rods 126 engaged by the shoe-ends, screw into a rotatable sleeve 128 adapted to engage washers 134 so as to compress a rubber block 132 against one side or the other of the sides of a fixed member 130. In Fig. 22, the shoe ends engage a member 148 so as to tilt it in one direction or the other when the brake is applied, thus compressing one or other of 'the rubber blocks 152. In Fig. 14, the rubber blocks are replaced by springs 106 disposed between parts 104 and an internal collar on a fixed sleeve 108. The shoe ends engage threaded sockets 98 receiving threaded rods seated in the parts 104 and having operating collars 102. In Fig. 26 a threaded sleeve 140 which can be turned on threaded rods 126 engaged by the shoe ends has shoulders whereby it compresses a spring 144 against one end or the other of a fixed part 146 when the brake is applied. The sleeve 140 is turned by a gear 268, provided on an operating spindle and engaging teeth 270 on the sleeve. A release spring connected to the shoe ends engages the teeth 270 to prevent undesired turning of the sleeve. This device is shown in a brake having applying mechanism similar to that shown in Fig. 10. The Specification as open to inspection under Sect. 91 comprises also a further construction, Fig. 27 (Cancelled), in which the shoe ends engage by thrust members 372, 374, the grooved coned head 390 of a pin screwed into a housing 376 carried by a plate 378 pivoted at 380 to the anchor plate. When the brake is applied part of the torque of the primary shoe is taken by one or other of a pair of rubber blocks or springs 384, disposed in a fixed housing 386 and engaged by an arm 382 of the plate. The shoes are adjusted by turning the pin 390. The blocks or springs may bo pre-loaded so that initially only the primary shoe acts on the drum. This subjectmatter does not appear in the Specification as accepted.