Patent GB-190912968-A (GB)
Title: Improvements in Air Brake Testing Systems.
Inventor: DUKESMITH FRANK HUTCHINSON
IPC: B60T17/22
Filed: 1909-06-02
Granted: 1909-11-18
Abstract: 12,968. Dukesmith, F. H. June 2. Brake signals and alarms.-An air-brake testing mechanism which sounds a whistle when the trainpipe pressure exceeds the normal is shown in three forms-(1) for use in passenger service with a train pipe and a whistle pipe, (2) for use in freight service when no whistle pipe is available, and (3) a form in which by varying the passages and ports and supplying attached devices in one case and removing them in the other, the apparatus can be adapted for either passenger or freight service. In all three forms, cocks are provided whereby the train-pipe may be tested or the brakes applied by hand. Fig. 1 represents the form used for passenger service. In this arrangement, the train pipe communicates with a chamber A separated from a chamber B by a valve controlled by a flexible diaphragm 5 and a spring 7. The diaphragm is held in place by screwing down the cover portion 2 into connexion with the annular flange of the casing. The chamber B has an exhaust port 20 and communicates with a chamber C, divided by a flexible diaphragm 13 from a chamber D. The diaphragm 13 is connected to a valve 14 closed by a spring 22 and by the pressure of the whistle pipe. If the pressure in the train-pipe rises above the normal, the valve 4 is opened, and air from the pipe passes into the chamber C and opens the valve 14, thus allowing the pressure to exhaust from the whistle connexion. The air in the chambers B, C escapes through the port 20, which also serves to reduce any excess of pressure in the train-pipe, above the tension of the spring 7 that may have accumulated through accidental overcharging. A by-pass 10<a> is provided extending from the train-pipe and is connected with a cutout cock and whistle. The cock may be set to operate the whistle or to exhaust the air from the train-pipe to apply the brakes. In the form used for freight service, the chamber B is directly connected to a whistle, so that, when the valve 4 is opened, the whistle is blown. A by-pass is disposed between the train-pipe and the chamber B and has a cock and a check valve to prevent air from passing back through the cock. The operation of the cock either blows the whistle or applies the brakes. Figs. 3 and 4 show the same main casing arranged for passenger and freight service respectively. As shown in Fig. 3, the train-pipe communicates with a chamber A', in which are two diaphragms of unequal area connected to a valve D<1>, which closes the whistle pipe 8 under action of spring 7<1>. When the pressure exceeds the normal, the valve D' is opened, and the whistle signal-pipe is exhausted through the open port F. A pipe C leads from the train-pipe port, and has a whistle H and a cock J for testing by hand or applying the brakes. As shown in Fig. 4, the port F is closed, and a by-pass M is opened. The pipe 8<1> communicates with the whistle and, when air from the train-pipe raises the diaphragm B<1> and so opens the valve D<1> air passes down the pipe 8<1> through the by-pass M, and so blows the whistle. The pipe G is removed in this form, and a by-pass is arranged between the train-pipe port and the pipe 8<1>, and is provided with a cock by means of which the whistle can be sounded by hand, or the brakes applied.