GB447923A - Improvements in or relating to vehicle brakes - Google Patents

Abstract

447,923. Adjusting internal brakes. CLENCH, E. C. S., and AUTOMOTIVE PRODUCTS CO., Ltd., Brock House, Langham Street, London. Nov. 30, 1934, No. 34464. [Class 103 (i)] In automatic wear-compensating mechanism for an internal-expanding brake operated by toggle linkage 16, 17, at least one of the toggle links engages a shoe by means of a pin-and-slot connection the position of the pin in the slot being determined by an adjustable abutment through which power is transmitted from the link to the shoe. Toggle link 16 has a pivot 22 engaging in slot 23 in shoe 10. Pivot 22 engages liner 25 pivoted at 26 and held in position by snail cam 27 engaging the lever at 30. The cam is adapted to be turned to adjust the position of the pivot 22 by a one-way ratchet 36 in a lever 32 which is moved by a pin 40 when the movement of the shoe is excessive. The lever moves freely on the shaft of the cam during brake-applying movement and moves the cam during the releasing movement. A similar mechanism may be arranged on the other toggle link 17. In a modification, the cam is turned by a ratchet wheel and a pawl on the brake back plate. In the modification shown in Fig. 5, a manually or automatically adjusted stop 48 is adapted to hold the shoe in a new position when wear occurs and a spring 57 therein moving the toggle 16, 17 so as to engage the roller 19 with the cam 21, moves the pivot 22 along the slot 50 in the shoe and spring- pressed wedges 53, 54 hold the pivot in its new position. The adjustable connection between a toggle link and a shoe may be a ratchet. The toggle linkage is operated by a cam 21 rotatable about the axis of the brake drum and which may be operated by servo brake shoes.