GB1068198A - Load-dependent braking apparatus - Google Patents

Abstract

1,068,198. Brake transmitting mechanisms. WESTINGHOUSE BRAKE & SIGNAL CO. Ltd. Sept. 28, 1965 [Oct. 27, 1964], No. 43733/64. Heading F2E. A load-dependent braking apparatus for a railway vehicle 1 is provided with a variable load mechanism 6, including a block 35 in which is pivotally mounted a first fulcrum 36 and a vertically slidable second fulcrum 40, and includes two bell-crank levers 13, the position of each one of which is dependent upon the load on a respective axle through linkages including weighing mechanisms 10, bell-crank levers 11 and push-rods 12, a roller member 14 which is urged by a spring mechanism (not shown) in a direction tending to engage both bell-crank levers 13 but which for any given load at the location engages only the bell crank lever associated with the most lightly-loaded location such that the position of the roller member 14 is dependent upon the loading at the most lightly-loaded location the position of the roller member 14 to alter the position of the second fulcrum 40 thus determining the degree of braking effort exerted by the apparatus. The variable load mechanism 6 includes the block 35 in which is pivotably mounted, the first fulcrum 36 resiliently urged into its position indicated in Fig. 2 by a spring 37 acting on the fulcrum through a plunger 38. Vertically slidable within the block 35 is the second fulcrum 40 connected by a linkage 41 to a rod 33 by which angular movement of the rod 33 determined by the position of the roller member 14 is tranlated into linear sliding movement of the fulcrum 40. A lever member 17 is pivoted to crosshead members 8, 9 which are coupled to the upper and lower rods 5 respectively shown entering the variable load mechanism 6 in Fig. 1. In operation, upon the commencement of the braking operation, a brake cylinder 4 will cause the crosshead 8 to be moved to the right and as the force exerted by the spring 37 is of suffi-. ciently large magnitude as not to be overcome by the force exerted against it by the lever 7 during movement of brake blocks 3 into engagement with the wheels 2 of the rail vehicle, the lever 7 will be pivoted in an anti-clockwise direction about the first fulcrum 36 so as to move the crosshead 9 to the left. This movement will continue until the brake blocks 3 engage the wheels 2 at which instant the lever 7 will be substantially vertical. After the brake blocks have engaged the wheels 2 continued operation of the brake cylinder 4 will cause the force in the brake rigging to increase to overcome the force exerted by the spring 37 so that the lever 7 will then move into engagement with the second fulcrum 40, the position of which will have been determined by the loading of the vehicle 1. The force transmitted to the brake blocks 3 will then be proportional to the loading of the vehicle at the most lightly loaded end. The invention may be applied to an empty/load braking apparatus by ensuring that the second fulcrum has merely two extreme positions rather than being adjusted throughout the whole length of its movement.