Patent GB-190307470-A (GB)
Title: Improvements in or relating to Pneumatic Apparatus and Valves therefor Adapted for use in Operating Railway Signals and Switches and for other similar Purposes.
Inventor: GRIFFITH LAWRENCE
Filed: 1903-03-31
Granted: 1904-03-31
Abstract: 7470. Griffith, L. March 31. Interlocking; safety and locking bars; semaphore signals.-Relates to pneumatic apparatus and to valves therefor, adapted for use in operating railway switches, signals, &c., in which pneumatic apparatus or system less piping is required than is usual and the air under pressure only enters the pipes when the operating handle or lever is in proper position. Means are provided for locking the handle in its operative position until the switch has been set, and for unlocking it when the switch is set, but only to allow it to be moved to full reverse or normal position. The apparatus is shown diagrammatically in Fig. 1 ; Fig. 2 shows the apparatus near the switch, Fig. 6 shows one of the diaphragm-operated seat valves 10, 11, Figs. 13 and 16 show the distributing slide valve X, Fig. 37 shows the distributing-valve D, and Figs. 56 and 69 show modifications of the valve D. The operating- shaft 71 has rigidly attached to it the two quadrants 23, 24 and the arm 73 for operating the top slide 60 of the distributing-valve X. The reverse and normal quadrants 23, 24 have locking-slots 25<1>, 26<1>, lugs 25<2>, 26<2>, and shoulders 25<3>, 26<3>, and rods 75, 76, borne upon the diaphragms of the casings 25, 26, have rollers 25<4>, 26<4> to engage with the slots. When the shaft 71 is moved from normal to reverse position, air passes from the main 7<1> to the pipe 17, and; when moved from reverse to normal, air passes to the pipe 16. The pipes 16, 17 lead to the diaphragm-operated seat valves 10, 11, and to the diaphragm casings 25, 26. The pipe 17, by the pipe 15 and the chamber of the valve 11, communicates with the pipe 9 and the cylinder 63, and also with the pipe 6 and the valve D. The pipe 16, through the pipe 14 and the valve 10, communicates with the pipe 8 and the cylinder 63, and also with the pipe 4 and the valve D. Pipes 1, 2 lead from the valve D to the operating-cylinder 64, and pipes 3, 5 from the valve D to the underside of the diaphragms 89, 86 of the valves 11, 10. The piston-rod of the cylinder 64 is connected with the motion-plate 69 provided with the usual camgroove 92 for the switchoperating bar 94. The lockrod 97 of the switch co-operates in a usual manner with the motion-plate to lock the switch points in their normal or reverse positions. A suitable detector bar 101 locks the switch when a car rests at the switch. The motion-plate 69 has a second slot 106 engaged by the roller 83 which is adapted to be inserted into or withdrawn from the slot recesses 107, 108, to hold or release the motionplate and thereby the switch points. When the slides of the valve X are in the normal position, Fig. 13, or in the reverse position, pressure air is cut off and the apparatus air is exhausted by the pipes 20, 21. If pressure air remains in either pipe 16 or 17, the valve parts are locked at one-third stroke until the air is exhausted. When the operating-lever is at two-thirds stroke, it is locked, and pressure air is admitted to the pipe 17 ; but, after release, the pipe 7<1> is cut off and air in the apparatus exhausts from pipes 16, 17 through the valve. The stroke of the valve D, Fig. 37, near the switch is divided into two parts and its ports are so arranged that, upon the completion of the stroke of the piston 67 in the cylinder 64 and upon the movement of the parts of the valve D to complete reverse or normal positions, air is led to valves 10, 11 to operate them and to indicate that the switch points have been completely moved. In the modified valve D shown in Fig. 56, when the parts are in full normal or reverse position, air under pressure is maintained in the end of the cylinder 64 last charged until the rest and movement of the piston 67 in the other direction. In the modified valve D shown in Fig. 69, in the normal or reverse positions of the valve, the ports are arranged to place both ends of the cylinder 64 in communication with the atmosphere. The upper slides of the slide valves X, D make complete strokes in both directions, and the under slides are carried only during part of the movement of the upper slides by means of the abutments 138, 139 on the under slides and the spring catches 133 which bear stops 134, 134' and release lugs 135, 135'. To maintain the valve parts in vertical relation, adjustable roller springs press upon the top of the upper slides of the valves. A casing is provided for the valve D. On the top slide 60 of the valve X, Fig. 16, is the spring trigger 121 to co-operate with the notches 125, 126 on the under slide 61 and with the pins 127, 128 thereon so as to prevent return movement after a one-third or two-thirds movement of the operating-lever in either direction. The valves 10, 11 have upper and lower valve heads 110, as shown in Fig. 6, but, in modifications, there are two upper valve heads and one lower valve head, and two upper and two lower valve heads respectively.