GB578038A - Improvements in or relating to adjusting means for brakes - Google Patents

Abstract

578,038. Brakes. AUTOMOTIVE PRODUCTS CO., Ltd., and PARNELL, F. G. Nov. 6, 1944, No. 21774. [Class 103 (i)] An adjusting device for a brake shoe or other brake friction element comprises a split resilient ring frictionally engaging one member on which it is displaced by excessive application movement of the friction element and abutting on a surface on a second member to locate the friction element in its off position, the surface being chamfered to increase the frictional engagement of the ring with the first member. A brake is shown comprising a pair of fixed diametrically arranged hydraulic cylinders, each formed with an arcuate slot 15 providing the pivotal mounting for one of a pair of shoes, one .end of the other shoe being connected to the piston 16. A seal 18 and a filler 19 are provided. A resilient split ring 26 grips the piston with which it moves outwardly in an application until it engages the face 25 of a collar 23, and if wear of the friction lining occurs the piston moves through the ring. In release the piston returns with the shoe and the ring until the chamfered face 27 on the ring engages a correspondingly shaped face 22 on the cylinder. The ring is tapered in radial width towards its ends and the chamfered face 27 may be concentric either with the inner or outer diameter of the ring; in the latter case the engagement with the face 22 is only at a point at mid-length of the ring which tends to tilt the ring relatively to the piston and increase the grip. In a modification as applied to a brake comprising a pair of shoes pivoted at adjacent ends and operated by a cylinder having a pair of pistons respectively engaging the other ends, the adjusting device comprises for each shoe a telescopic link pivoted at its ends to the back plate and to the shoe, a ring such as 26 being provided on the inner member of the link. In a further construction, Fig. 6, the ring 26 grips a sleeve 47 and is urged by a spring 50 into permanent engagement with the face 22. In an application the piston moves relatively to the sleeve until the clearance between the piston shoulder 48 and the sleeve is taken up. With further movement of the piston due to wear of the shoes, the sleeve is pushed through the ring 26. The ring instead of frictionally engaging an inner member such as piston 16 may engage the outer member or cylinder the recess such as is provided by the collar 23 being formed in the inner member and the chamfered face of the ring on its inner side. In brakes that are operated by a transversely moving wedge acting on the shoe ends through tappets, the tappets may be provided with the adjusting device.