Patent GB-191113310-A (GB)
Title: Improvements in and relating to Railway Signalling Apparatus.
Inventor: GLENN SAMUEL LEAR
IPC: B61L5/16
Filed: 1911-06-02
Granted: 1912-05-30
Abstract: 13,310. Glenn, S. L., and O'Donnell, J. P. June 2. Visual outdoor signals.-In a system in which signals or other parts are operated by power controlled by a cabin slide, and in which a return indication or the like is given, a device is provided in the operating path, which is moved by the power to clear that path and at the same time to break the indication path, which latter remains broken as long as power is passing in the operating path. The system may by wholly pneumatic, electro-pneumatic, or electric. Fig. 1 shows the invention applied to the pneumatic system described in Specification 183/00, in which the slide L controls the signal A<1>. The slide valve V<1> controls the admission of power from the main X<1> to pipes p, o leading to diaphragm valves R<2>, R<3> which control the admission from the main X' to pipes e, f respectively, which lead to the top and bottom of the operating-cylinder A<2>. The pipe f connects through a valve device IV, which also connects the pipes 17, n leading to the diaphragm valve R<1> of the indication cylinder I<10>. The valve IV comprises pistons 5, 6, Fig. 2, the latter having an extension 7 engaging the former, which is depressed hy a spring 9. Ports 11 and 12 lead to the atmosphere, holes 14, 15, 16, to pipes f, n, 17, and the port 18 by the pipe 19 to the bottom of the cylinder A<2>. When the slide L is pulled to lower the arm A<1>, the valve V<1> admits air to the pipe o to operate the valve R<2>. Air then passes up the pipe f, lifts the pistons 5, 6 and connects the ports 14, 18 to allow air to pass to raise the piston of the cylinder A<2>, the port 16 is opened to atmosphere through the ports 12, the connexion between the ports 15, 16 by the annular groove 13 is cut off, and the port 15 is closed. The parts remain in this position until the slide L is returned, when air passes to the valve R<2> which is operated to admit air to the pipe e to depress the operating-piston and restore the signal to danger. The valve IV has meanwhile returned to normal, and air passes along the indication circuit to operate in the cylinder I<10>. The indicator cannot be given unless the valve R<3> has placed the pipe f to exhaust to return the valve IV, but the counterweight will return the signal. Where the indication is given electrically, the upper piston 6 is replaced by a contact completing the circuit only when the lower piston is in the normal position. Where the system is wholly electric, the lower piston is replaced by a solenoid 30, Fig. 4, the plunger 31 of which carries a contact 32 normally connecting contacts 33 in the indication circuit. When the slide is put over, current passes through wires 35, 37, 38, 36, energizing the solenoid; this current is not strong enough to operate the signal, but, when the plunger rises, the contact 32 bridges contacts 39 in a branch circuit 40, 41, which passes a stronger current to operate the signal. The above-described indicating-means may be used for operating a check lock on another slide.