Patent GB-190416277-A (GB)
Title: Improvements in Pneumatic and like Railway Signalling Systems and Apparatus therefor.
Inventor: O'DONNELL JOHN PATRICK
Filed: 1904-07-22
Granted: 1905-07-20
Abstract: 1 6 , 2 7 7. O'Donnell, J. P., [Cosserat, W.A. P.]. July 22. Semaphore signals; hand-levers; interlocking. - In pneumatic systems for operating railway signals and points chiefly on single-line railways, several special forms of valves are used to diminish the length of pipe necessary. Fig. 4 shows a valve operated by hand for controlling a signal. The cylinder 26 forms the seat of the valve and is fitted with the pipe 1 which passes to the signals and is connected to the port 34. The port 33 is connected to the compressedair supply by a channel running axially along the cylinder. A number of such valves may be mounted on a cylinder and interlocked by locking bars with tappets, which run in slots in the surface of the cylinder. The sliding part 28 moves in grooves formed between shoulders 27, and is provided with a handle 4. This part is held in position by springs 29 with bearing-rollers 31, the pressure being adjustable by the thumb-screws 32. In the position shown, the pipe 1 is open to atmosphere, and, by reversing the handle 4, the port 35 admits air from the main 33 to the pipe 1. For the purpose of detecting points and switches, the valve shown in Fig. 9 is used. The switch tongues carry the usual blades 10, 11, which are provided with notches 5 into which the piston 13 may rise under action of compressed air in the pipe 1 if points are properly set over. If the piston is able to rise, air then passes on to the pipe 1<a>. Several cylinders may be used in conjunction with one pair of blades 10, 11, which are suitably notched. Fig. 1 shows the connections for signals on a single line. The points are operated from a hand-frame in the usual manner, and the blades 10, 11 pass to the detector 5. The handle 4 being reversed, air enters the pipe 1 from the main 3 and passes through the detector 5 to the cylinder 16, the piston of which sets the signal A at " line clear." Through the link 18, the piston of the valve 17<a> is moved to admit air from the cylinder 16 to the pipe 1<b> through a port in the walls of the cylinder and valve. The signals B, C are then set in a similar manner to the signal A by the air thus passed along the pipe 1<b>. To return the signals to "danger," the valve 2 is moved back, thus opening the cylinder 16 of the signal A to exhaust ; the signal is brought back by gravity and opens the pipe 1<b> to exhaust through the valve 17<a> ; the signals B, C return to normal in a similar manner. For signals at a loop line, as shown at Fig. 2. a number of valves 2 are provided and suitably interlocked. The points may be operated pneumatically as described below or from the ground frame 6, and a detector 5 is used with three cylinders. To set the signals A, B, C for a straight road when the points are adjusted the handle 4<a> is moved over, and air passes through detector 5 to the signal A, and as above described to the pipe 47 and valve 46. Fig. 13 shows this valve in detail, its function being to admit air from either of the pipes 47, 48 to the pipe 1<b>. The air in the pipe 47 forces the piston 51<a> towards the right and makes a channel through the hollow part of the piston from the pipe 47 to the pipe 1<b>. The ports 54, 55 are small, and serve only to pass such small quantities of air as may leak through the pipes. They thus prevent accidental movement of the piston 51<a> by leaking air in the pipes. The air then passes along the pipe 1<b> and operates the signal B. The valve 4<c> is then operated and air passes through the detector 5<a> to the valve 57, which is shown in detail in Fig. 14. The chamber 59 contains a piston valve 60 and a mitre valve 61. In the position shown, the pipe 1<b>, is open to the atmosphere through the port 62. The mitre valve 61 rests on feet 63.. The head 64 of the piston valve is raised from the tubular portion to give a clear passage in the position shown from the pipe 1<a> through the piston 60, and beneath the feet of the mitre valve 61 to the pipe 58. Air entering the pipe 58 causes the mitre valve to rise against its seating and to lift the piston valve 60 against its seating, thus closing the pipe 1<a> and connecting the pipes 58, 1<b>. The air in the pipe 1<a> therefore passes to the pipe 58 and the valve 56, which is similar to the valve 57, and thence to the pipe 1<b> and signal C, which is set in the manner described. The valve 41 is connected to the signal C so that, on the return of this signal, the air in the cylinder 39 is exhausted. The dotted lines show an arrangement by which the points may be worked pneumatically by means of a cylinder 66 with piston 67 actuating the motion plate 7, the valve 70 being an ordinary three-way valve, and air being admitted to the cylinder 66 by the valve 4<a>, 4<d> used for setting the corresponding signals A, D. For a loop road, the lever 4<d> is operated and the signals D, B are set in a similar manner to the signals A, B, the valve 46 admitting air from the pipe 48 to the pipe 1<b>. By the system shown in Fig. 3, less pipe is required by making use of a valve 73, shown in detail in Fig. 12. For a straight road, the lever 4<a> is set over, and air passes along the pipe 79 to the pipe 79<a>, and sets the signals A, B as described, and also moves the plunger 80 of the valve 73 to connect the pipes 83, 84. The lever 4<c> is then operated by an Annett's key from the ground-frame lock 77. Air then passes through pipes 75, 83 to the signal C. For the loop road, the lever 4<d> is reversed and admits air to the pipe 74, 83. The plunger 80 of the valve 73 is moved to connect the pipes 83, 83<a> and to open the pipe 84 to exhaust through the port 81<a>. The signals D, B are then set as described above. The ports 81 are small and serve to prevent the action of the valve by leakage around the piston.