Patent GB-191305854-A (GB)
Title: Improvements in and in Apparatus for Signalling to or Communicating with or Stopping Trains and Locomotives on Railways and for other analogous purposes.
Inventor: SNOW WILLIAM HENRY
IPC: B61L3/04
Filed: 1913-03-10
Granted: 1914-03-10
Abstract: 5854. Snow, W. H. March 10. Track apparatus actuating signals on trains and for stopping trains.-A locomotive or other railway vehicle is provided with a movable part adapted to be held in equilibrium by a jet of fluid, say steam. A movable baffle-plate on the track is adapted to project as the train passes into the gap between the nozzle and the movable part. The deflection of the jet destroys the equilibrium of the movable part, the consequent motion of which operates apparatus for actuating a visual signal on the train or mechanism for stopping the train, or both. For provision for backward running, duplicate sets of apparatus are provided on each side of the engine, one of which is rendered alternatively inoperative according to the direction of running. In the application of the invention to a locomotive provided with an air-pressure brake, a casing e, Figs. 1, 6, and 8, is fixed on each side of the engine. Projecting from the casing is a lever c, provided with a blade a adapted to receive the impact of a jet of steam from a nozzle b. The lever c is secured to a shaft d carrying a downwardly-projecting trip lever f adapted to engage teeth h, i on a plunger j. One portion of the plunger forms a piston valve u controlling ports l, m, n, o, Figs. 6 and 8. The port l communicates with the port o by way of a passage p, Fig. 6. The ports m, o communicate respectively with conduits q, r, and thence with pipes s, t, Fig. 1, leading to the signalling-device and train-pipe respectively. The port n communicates with the atmosphere. The upper end of the plunger j forms a piston w, Fig. 6, under which air is admitted through a passage x, Fig. 8, for the purpose of raising the plunger when required. In the lower part of the casing e is a dash-pot y. The lower end of the plunger is provided with escape holes 22, 23, Fig. 6, differing in size, for the oil in the dash-pot, The lower part of the casing c is kept full of oil, so that on the withdrawal of the plunger the dash-pot is immediately refilled. The upper end of the plunger is hollow, the lower end of the hollow portion communicating with the narrow portion of the valve u by way of passages 2, and the upper end being closed by a valve 3 pressed down by a lever 4. The lever 4 is connected by a spring 6 to a rocking lever 7, which in turn is connected by a rod 9 to an extension 10 of the trip lever f. When, therefore, the blade a is relieved of the impact of the jet, the spring 6 rotates the trip-lever f to release the plunger j. When the engine reaches a baffle-plate 21 on the track, say at a distant signal, in position for giving a signal, the jet is cut off from the blade a and the unbalanced force of the spring 6 causes the trip-lever f to fly out and release the plunger j, at the same time forcing the plunger down by means of the lever 4. The plunger then enters the dash-pot and moves slowly downwards. Meanwhile, the engine having passed the baffle-plate, the jet resumes action and the trip-lever f is moved inwards to engage with the tooth i and hold the plunger in its second position. In this position, the conduits r, q, Fig. 8, are placed out of communication and the conduits n, q put in communication. The conduit q is connected by pipes s to a visual signal 65 operated by a piston 20. The effect of substituting atmospheric pressure for train-pipe pressure, caused by the falling of the plunger, is to cause the piston 20 to fall and display a danger signal. When the engine reaches a second baffle-plate 21, say at a home signal, the plunger j is tripped for a second time and falls to its lowest position. This movement is rapid owing to the uncovering of the large oil-escape hole 23. In this position the conduits r, n are in communication, i.e., the train - pipe is opened to the atmosphere, whereby the brakes are caused to be applied. The apparatus is reset by the driver causing air to be admitted under the piston w, Fig. 6, through the conduit x, Fig. 8. Should the spring 6 break, the valve 3 opens and the consequent escape of air from the train-pipe and application of the brakes gives warning of the failure of the apparatus. As shown in Fig. 1, the apparatus is duplicated for running in both directions, and one set is rendered inoperative by the provision of interconnected valves 36, 61 operated by a rod 39 connected to the reversing- gear. Steam is admitted to one or other of the jets b by way of pipes 55, 35, 37, 38 controlled by a valve 34. Air pressure is admitted to the conduit r by way of pipes 47, 41, 59, 60, t, and to the conduit x by way of pipes 47, 41, 59, 75, 76, 77. The supply of compressed air from the train-pipe to the apparatus is controlled by a valve 42, the back of which may be subjected to air pressure by means of a cock 51 controlled by the brake-control handle, so that when the brakes are applied the valve 42 is closed and the apparatus rendered inoperative. A slotted spindle 48, however, ensures the opening of the valve 42 when the regulator 49 is opened. The air pressure in pipe 41 sustains a piston 53 against a spring 56. The piston 53 is mounted upon the spindle of the valve 34 so that when the valve 42 is closed the valve 34 also closes, and the supply of steam to the nozzle b is cut off. A valve 68, controlled by a hand-lever 74, enables the driver to admit air to the conduit x for resetting the plunger. A hand-wheel 58 enables the valve 34 to be closed positively when it is required to render the apparatus inoperative, for example during shunting operation. The apparatus may be modified for use with vacuum brakes.