Patent GB-191126946-A (GB)
Title: Improvements in or relating to Compressed air Brakes.
Inventor: LIPKOWSKI JOSEPH DE
IPC: B60T15/02
Filed: 1911-12-01
Granted: 1912-04-04
Abstract: 26,946. Lipkowski, J. de. Dec. 14, 1910, [Convention date]. Fluid-pressure.-In a distributing - valve for compressed - air brakes for railway vehicles and other purposes of the kind constructed so that, during applications of the brakes, the brake-cylinder pressure obtained is proportional to the reduction in train-pipe pressure, and during release, the fall in brake-cylinder pressure is proportional to increase in trainpipe pressure, the slide valve is operated by piston apparatus comprising two flexible diaphragms and an intermediate cupleather piston. Means are also provided for preventing oil carried along by the air from obtaining access to the working parts. An accelerating - valve may also be fitted, and is provided with a cock adapted to occupy four positions so as to put either or both the accelerator and distributor into operation, or to cut out both. The distributor comprises a stem B, Fig. 1, connected to diaphragms B', B<3> of different areas, to a cupleather piston B<2>, and to a slide valve A. The space below the diaphragm B' communicates with the train-pipe by passages c<1>, c<2>, c<3>, and the space above this diaphragm with a supplementary reservoir by a passage d, Fig. 2. The diaphragm B<3> is open at the lower side to the brake cylinder by ports e<1>, c<2>, and at the upper side to atmosphere. The brake reservoir communicates by ports g<1>, g<2> with a port g<3> in the valve seat, which is also provided with a port b<2> connected to the brake cylinder by passages e<3>, e<2>, a port b<3> connected with the atmosphere at b<5>, and a port b<4> communicating with the train-pipe. The slide valve A is formed with two cavities a<1>, a<2>, Fig. 5. In the running position, Fig. 1, the port b<4> is uncovered, and train-pipe air passes to the supplementary reservoir at d, and to the brake reservoir by means of ports b<1>, a<1>, g<3>, the brake cylinder being exhausted by the cavity a<2>. When the train-pipe is vented, the slide valve first takes up a preparatory position, Fig. 7, in which the train-pipe is cut off from the reservoirs, but the brake cylinder is still open to exhaust. Further venting brings the valve to the neutral position, Fig. 8, in which the brake-cylinder exhaust is also cut off, and afterwards to the application position, Fig. 9, in which air passes from the brake reservoir to the brake cylinder by ports g<3>, a<1>, b<2>. The air supplied to the brake cylinder also enters beneath the diaphragm B<3>, so that the valve returns to neutral position, Fig. 8, when the brake-cylinder pressure becomes proportional to the reduction in train-pipe pressure, the proportion being regulated by the areas of the diaphragms and piston B<2>. A gradual release is obtained by increasing the train-pipe pressure sufficiently to bring the valve to the position shown in Fig. 7, the valve returning to neutral position when the fall in brake-cylinder pressure is proportional to the increase in train-pipe pressure. The diaphragms are mounted in malleable castiron heads fixed on the stem B by nuts so that they may be separately removed. The oil carried by the compressed air is prevented from entering the apparatus by a wall c<4>, and is collected and drained from a basin C'. In modifications of the distributor, means are provided for reducing or nullifying the effect of the piston B<2>, either by forming it as a shoulder of the required area upon a narrow portion of the stem B, or by providing an oppositelyacting piston of slightly less area below the diaphragm B'. The accelerator comprises two diaphragms L', L<2>, Fig. 10, controlling a valve L which is normally closed by a spring M. A reservoir O between the diaphragms is charged from the train-pipe N by means of a restricted port p. When large reductions in train-pipe pressure occur, the air in the reservoir O is not able to pass sufficiently quickly through the port p and moves the diaphragms so as to open the valve L. Specification 17,254/06 is referred to.