GB197345A - Improvements in or relating to fluid pressure braking apparatus - Google Patents

Abstract

197,345. Poultney, E. C., Gilling, A. H., and Yorkshire Engine Co., Ltd. Nov. 8, 1921. Fluid-pressure. - Differential pistons are arranged on each truck so that the brakes will be operated with full power or with partial power according to the setting of a valve. The cylinders of the pistons are situated in a single vacuum reservoir or like housing. Maximum braking is obtained by a summation of pressures acting in the same direction, and reduced braking by a difference of pressures. In the arrangement shown in Fig. 1, the lower piston face g is subject to train-pipe pressure, the smaller upper face d to vacuum reservoir pressure, and the upper annular face e either to train-pipe pressure or to vacuum reservoir pressure according to whether the truck is empty or loaded. The pipes h, j lead to a valve by which the alteration in connections for empty and loaded running is effected. In a modification, the piston is inverted so that the trunk providing the annular face is on the lower side. In a further modification, a double piston is arranged as in Fig. 4 so that the face w is subject to train-pipe pressure, the face s to vacuum reservoir pressure, and the intermediate faces t, v to either train-pipe or vacuum reservoir pressure according to the setting of the valve connected to the pipes h, j. In this way three different braking powers may be obtained. In a further modification, two differentially working pistons of different diameters are arranged on the same piston rod. Fig. 6 shows an arrangement in which two cylinders of different diameter are arranged in a single housing, variations in braking power being obtained by subjecting the piston faces 5, 6, 7, 8 to vacuum reservoir or train-pipe pressure. The upper ends of these cylinders may be open to the vacuum reservoir. Pistons of equal size may be employed, one being coupled to a shorter lever than the other. In . a further modification, a trunk on a single piston works within a trunk carried by the upper cover of the cylinder.