Patent GB-388291-A (GB)
Title: Automatically acting brake adjuster
IPC: F16D49/10
Filed: 1932-07-18
Abstract: 388,291. Brake adjustments- BRINCK, E. J. M., S÷lvesborg, and OLSSON, R. V. A., Kyrkhult, near Karlshamm, both in Sweden. July 18, 1932, No. 20263. [Class. 103 (i).] Brakes of the kind comprising coacting internal and external members and in which the internal brake member, comprising a rotating drum or stationary brake shoes, consists of a number of segments are provided with automatic adjusting means adapted to move 'both ends of each segment substantially in a radial direction to the same extent to compensate for wear. In one construction, Fig. 1, the brake drum comprises a pair of segments 2, 3, rotating with the shaft 1 and having disposed between them wedges 5. The brake shoes or straps 7, pivoted at 11, extend axially beyond the segments on each side so that they may engage members 13, each connected by a pin 18 to a lever 15 pivoted at 16 and engaging by means of a slot a pin 20 on the wedge. The pin 20 passes also through a slot in a lever 22 which is provided with a second slot through which passes a pin 24 on the lever 15. The arrangement of the two slots at an angle to each other for the pin 20 guides the pin radially. As the linings on the brake straps 7 wear the edges of the straps contact with the members 13 and the wedges 5 are moved radially inwards so as to separate the drum segments 2, 3 and increase its effective diameter. The wedges may be replaced by right-and-left-handed screws connecting the drum segments. In the construction shown in Fig. 3, the drum comprises four segments 38 guided radially in relation to a disc 33 on a boss 32 keyed to the shaft 1. A disc 41 screwed on the boss 32 and normally rotating therewith has conical parts 40, 43 fitting corresponding parts on the segments 38. When the brake straps 36 are applied to these segments and the lining 35 is sufficiently worn, the straps contact the edge 42 of the disc 43, causing the disc to rotate relatively to the boss 32 and thus to move axially and force the segments radially outwards. Pawls 47 hold the disc 41 in the adjusted position. In a further construction, a disc such as 41 which is adapted to be rotated relatively to the drum segments by the engagement with the edge of the disc of the brake straps is provided with teeth on its side face geared to toothed wheels secured to radial screws which screw into nut members carried by a disc keyed to the shaft. The outer ends of the screws carry heads to each of which one end of a flexible drum segment is secured, the adjacent end of the next segment being slidably carried by the head. Rotation of the screws by the disc 41 thus moves the heads and the segments radially outwards. Fig. 10 shows a brake comprising four internal brake shoes that are automatically adjusted. Each brake shoe 64 is riveted at one end to a head 65 and is slidably connected to the next head at its other end. Each head is carried by a pair of screws 68 which screw into a support 69. The heads 65 and supports 69 are radially guided on a fixed back-plate by pins and slots. The supports 69 contact with a cam disc 77 by the rotation of which on the shaft 1 the shoes are thus applied to the drum 62. The screws 68 carry worm wheels 71 geared to a worm 72 on a shaft mounted in the support 69 which carries a disc 73. As the linings of the shoes wear, the discs 73 contact with the drum 62 and are driven thereby so as to rotate the screws 68 and adjust the shoes 64. In a modification of this construction, the discs 73 and worms 72 are dispensed with and the worm wheels 71 are replaced by toothed wheels adapted for engagement with a radial toothed arm secured to the cam disc 77. When by reason of wear, the cam disc is turned sufficiently in applying the brake, the toothed arm engages the toothed wheel which it rotates during the release movement.