Patent GB-542168-A (GB)
Title: Improvements in operating mechanism for double-acting automatic brake slack adjusters
IPC: B61H15/00
Filed: 1940-05-21
Abstract: 542,168. Slack-adjusters for brakes. BROWALL, B. H., and SVENSKA AKTIEBOLAGET BROMSREGULATOR. May 21, 1940, No. 9037. [Class 103 (i)] Relates to slack-adjusting mechanism for brakes, such as described in Specifications 418,492 and 530,658, adapted both to decrease and increase the slack and comprising a member 4 slidable on a brake rod 2 against the action of a spring 5 by movement of the rod relatively to a rod 3 which may be fixed or may move as by being connected to a brake operating lever linked to the lever 1 to which the rod 2 is ,connected. The member 4 during brake application controls a coupling between the rod 2 and another rod during brake application so as to limit relative movement of these rods in the slack-increasing direction and to couple them together to transmit the brake pressure and in brake release effects relative displacement of these brake rods to reduce the slack when necessary. The invention consists in providing a latch which is the release condition and at brake application permits movement of the member 4 on the rod 2 against the action of the spring 5 but locks these parts together during the application movement. The spring 5 may thus be light. According to Fig. 1, a latch 12 is pivoted to an arm 6 on the member 4 and is controlled by a roller 14 which runs on the rod 3. In release, the roller 14 rests upon an incline 15 so that the latch is disengaged from the rod 2 but during the application movement, a roller 13 on the latch is held in engagement with an abutment 11 on the rod 2, as shown, so that the member 4 is coupled by the latch to the rod 2 and is moved thereby until when the rod 2 has moved a distance corresponding to normal slack, the engagement of the roller 14 in a recess 10 in the rod 3 disengages the latch from the rod 2 and locks the member 4 to the rod 3. On further movement of the rod 2 the member 4 slides relatively thereto. In a modification, Fig. 3, the latch arm 12 carrying the rollers 13, 14 is pivoted at 12a to an arm 20 pivoted at 21 to a casing 16 secured to the member 4. An abutment 27 pivoted at 28 to the casing has an arm engaging a shoe 26 pressed against the rod 3 by a spring 25 seated on a part 24 of the arm 20. In brake-released position, the member 4 can slide on the rod 2 against the action of the spring 5 since, as the arm 20 is free to swing to the right on the pivot 21, the latch 12 can move with the abutment 11 of the rod 2. But upon application movement of the rod 2 to the right, the drag of the shoe 26 on the rod 3 turns the abutment to a position in which it engages a part 23 of the arm 20 which is thus locked against movement on its pivot 21 so that the casing 16 and member 4 are coupled by the latch to the rod 2 until the latch roller 14 drops into the recess 10. Shocks to the vehicle while the brake is released, by causing the member 4 to slide on the rod 2 against the action of the spring 5, lock the adjusting device against undesired slack-increasing movement which would otherwise occur. French Specification 823,429 is referred to.