Patent GB-524222-A (GB)
Title: Improvement in operating mechanism for load brake devices
IPC: B61H13/32
Filed: 1939-01-24
Abstract: 524,222. Locking levers. SVENSKA AKTIEBOLAGET BROMSREGULATOR. Jan. 24, 1939, Nos. 2476 and 2477. Convention dates, Jan. 24, 1938, and Feb 24. 1938. [Class 80 (iii)] [Also in Group XXXIV] Leverage setting mechanism for variable leverage brake mechanism, in which a resilient connection between the setting handle and the actual leverage changing device permits the handle to be moved to the desired position when the device is immovable due to the brakes being applied, comprises a member between the handle and the resilient connection which is normally locked and which is unlocked by initial movement of the handle and then moved by the handle to change the setting. The variable leverage mechanism for a vehicle may comprise levers 1. 2, Fig. 1, interconnected by tie-rods 3, 4 pivoted to a lever 5 between which and the lever 2 is a member 6 movable to vary the leverage as described in U.S.A. Specification 1,898,528 or it may comprise a number of tierods between the levers which can be selectively rendered effective by reducing the lost motion between any one of them and one of the levers as described in Specification 507,891, [Group XXXIV]. The member 6 is set by linkage 7, 11, 11a, mechanism in a casing 12 and handles 26, 35. Between links 11, 11a is a resilient connection comprising a casing 13 connected to link 11 and springs disposed on each side of an abutment on the end of link 11a. The handle 26 and an arm 24 are secured respectively to coaxial shafts 25, 21 mounted in casing 12. Projections 40, 41 on sectors 27, 30 secured respectively to the shafts are disposed between the ends 36<1> of a spring 36 which thus couples the shafts for either direction of rotation. Shaft 21 is normally locked by engagement in one or other of the recesses 31 in sector 30 of a roller 38 on an arm 37 pivoted at 37a and urged by spring 39. Sector 27 has spaced cams 29 which normally lie opposite the projections on sector 30 between the recesses 31 as shown and which have inclined faces for engaging roller 38. The shaft 34 of the handle 35 on the other side of the vehicle is coupled to the mechanism by a sector thereon meshing with teeth 28 on sector 27. Initial movement of either handle to change the setting causes one of the cams 29 to disengage the roller 38 and torsion of the spring 36 which, as soon as the sector 30 is unlocked, turns the shaft 21 and sector to the same position relative to the shaft 25 and sector 27. Movement of the handle, the shafts and sectors is then continued until the roller 38 engages the next recess. If the member 6 is immovable due to the brakes being applied, link 11a moves with the handle and the power thus accumulated in the device 13 adjusts the member 6 to the corresponding position upon release of the brakes. In a modification, the resilient connection 13 is replaced by a torsion coil spring disposed between the shaft 21 of the arm 24 and the sector 30, this shaft and the sector each having a projection engaging the ends of the spring. In this construction, the shaft 25 is solid and extends to the other side of the vehicle where it is geared to the handle 35, the teeth 28 being thus dispensed with.