GB459448A - Improvements in or relating to track brakes for railways and the like - Google Patents

Abstract

459,448. Track brakes for vehicles. RAIL BRAKES, Ltd., 515, Australia House, Strand, London. July 4, 1935, No. 19176. Convention date, Aug. 31, 1934. [Class 103 (i)] In weight-operated track brakes for railway vehicles, having at least one downwardly swinging brake shoe beam, the cross-section of the beam is so shaped and disposed that the axis of smallest moment of inertia is normal to the path of movement of the beam this moment of inertia being so small as to allow deflection of the beam sufficient to apply an effective retarding force simultaneously to wheels of thickness varying within the usual limits. In Fig. 1, the brake beam S pivoted by means of a shaft H has a surface A upon which the wheels run so that the weight of the vehicle causes a surface B to be forced against the side of the wheels, the other side of which are forced against a fixed reaction beam R. In order to permit the beam to bend sufficiently for the surface B to be effectively applied simultaneously to relatively thin and thick wheels as shown in full and broken lines the axis X-X of smallest moment, of inertia of the cross-section of the beam passes through the axis of the shaft H. In Fig. 2, the beam S is carried by plates 1 connected by parallel links L1, L2 to the fixed frame 3 and in this case the axis X-X of minimum moment of inertia of the cross-section is normal to the tangent Y-Y of the path of movement of the beam. In Fig. 3, the link L2 is replaced by a roller 2 on the plate 1 which engages a surface 4 which may be arcuate to correspond with the arcuate path of the upper link or parallel to the tangent to that path or as shown inclined to that tangent. In a further arrangement the beam S is guided by the engagement of curved abutment surfaces on the plates 1 with upper and lower fixed inclined surfaces. To facilitate the entry of the wheels to the brake, the run-in end of the beam may be freed from enforced parallel movement by omitting the lower link L2, Fig. 2, or the roller 2, Fig. 3. Swinging beams may be provided on both sides of the wheels.