Patent GB-544053-A (GB)
Title: Improvements in automatic double acting slack adjusters for brakes
IPC: B61H15/00
Filed: 1940-09-27
Abstract: 544,053. Brake transmitting mechanism. SVENSKA AKTIEBOLAGET BROMSREGULATOR. Sept. 27, 1940, No. 14667. Convention date, Aug. 14, 1939. [Class 103 (i)] In slack adjusters of the kind adapted both to increase and to reduce slack and comprising a two-part brake-rod and a control member movable axially on the rod by an operating member against the action of a spring at a brake application to permit engagement of a member that couples the rod-parts the control member being returned by the spring at brake release for disengaging the coupling member, the spring acts on the control member through a separate support when this support is operated by the operating member so that normally and in the event of failure of the operating means during a brake operation the spring is ineffective in the control member and engagement of the coupling member is thus permitted to prevent slack increase. The adjuster shown is such as described in Specification 530,658 and comprises a brake-rod the parts 1, 2 of which are adapted to be coupled by a nut 3 engaging a quick-pitch thread on the part 1, an adjusting nut 4 being also provided. A control member 5 is movable axially against the action of a spring 7 during brake application by an operating rod 6. The spring 7 bears on a support 9 slidable on the rod 1 and which normally as shown abuts on a sleeve 10 secured to the rod 1 so that the spring does not act on the member 5. The nut 3 can thus bear on the abutment 17 of the rod 1 to lock the rods 1, 2 against relative slack increasing movement. In Fig. 1 a lever I is pivoted at 12 to support 9 and is linked at 15 to the member 5. Initial movement of the rod 6 relatively to the rod 1, 2 at a brake application operates the lever 11 to cause movement of the abutment 17 away from the nut 3 thus permitting relative slack-increasing movement of the rod-parts 1, 2, the abutment 16 on member 5 engaging the abutment 17. On further movement of the rod 6 the support 9 abuts the member 5 at 19 so that the parts 11, 9, 15, 5, move together further compressing the spring 5 and permitting re-engagement of the nut 3 with abutment 17 to couple the rod-parts 1, 2, the parts 16, 4 having been moved away from the parts 3, 17 respectively. 'In a modification, the members 11, 15 are replaced by a bell-crank pivoted to the members 5, 9 and operated by an incline surface on the rod 6 sufficiently to disengage the nut 3 from the abutment 17, the subsequent movement of the parts 5, 9 and the lever as a whole being effected by direct engagement of an abutment on the rod 6 with the member 5. In a further form, Fig. 5, a spring 7b acting directly on the member 5 normally holds that member in the right hand position but is too weak to prevent engagement of the nut 3 with abutment 17 in a brake operation. The support 9 of the main spring 7a is adapted to bear on the member 5 through a bolt 29 which is operated by a bell-crank 30 and a friction shoe 31 bearing on the rod 6. At release of the brake the bolt is withdrawn to permit the support 9 to abut on the sleeve 10. When the brake is applied the bolt is interposed as shown and further movement of the, rod 6 engages an abutment 32 therein with the member 5. Specification 421,759 also is referred to.