GB505795A - Improvements in automatic brake adjusting means - Google Patents

Abstract

505,795. Adjusting brakes. TRACHSEL, E., and HUESSY, W. March 2, 1938, Nos. 6495 and 6496. Convention dates, March 2, 1937 and Jan. 28, 1938. [Class 103 (i)] A device for automatically adjusting a brake shoe to compensate for wear of the lining and which is not affected by drtun expansion comprises a feeler having clearance from the drum equivalent to the normal shoe clearance and which is moved to contact the drum by the shoe acting through an adjustable member any excess movement of the shoe over that of the feeler effecting an adjustment of the member and thus of the shoe. In Fig. 1, each brake shoe 5 is connected by a telesoopic rod 17, 18 to one arm of a bell-crank 16 pivoted on the back plate, the other arm engaging a pin 11 sliding in a fixed casing 10. The pin 11 carries a feeler 12 faced with hard material. The parts 17, 18 of each rod are threaded internally and externally respectively and the part 17 is slit so that it grips the other part. When the shoes are applied the feeler also contacts the drum and if wear of either shoe lining occurs the corresponding rod 17, 18 is extended so that the shoe returns to an adjusted position, when the brake is released. If the drum exparids during braking the feeler and shoes move correspondingly and there is no adjustment due to the expansion. In Fig. 4, a pair of shoes 5 are pivoted respectively at diametrically opposite points 4 of the back plate and are applied by hydraulic cylinders 32. Each feeler in this case is formed by one arm 40 of a bell-crank independently mounted on the pivot 4 and having its other arm connected by a link, 42 to an arm 43 pivoted on the shoe. A friction washer is interposed between the arm 43 and the shoe at the pivot 44 to resist turning of the arm so that when the shoe is applied the feeler is moved thereby to contact the drum but if wear of the lining takes place, the arm is turned to increase the effective distance between the pivots 44, 39a and thus adjust the shoe. The feeler 40 has a forked end 34a embracing the shoe whereby it is positioned when the brake is released. A telescopic rod such as shown in Fig. 1, may be substituted for the parts 42, 43. The Specification as open to inspection under Sect. 91 includes a modification of Fig. 1, in which the bell-cranks are mounted on the shoe pivots 4. This subject-matter does not appear in the Specification as accepted.