Patent GB-190111932-A (GB)
Title: Improvements in Automatic Fluid Pressure Brake Apparatus for Railway Vehicles.
Inventor: CORRINGTON MURRAY
Filed: 1901-06-11
Granted: 1902-05-29
Abstract: 11,932. Corrington, M. June 11. Brakes, compressed-air. Relates to means for re-charging the auxiliary reservoirs while the brakes are applied, and afterwards releasing them with certainty. Fig. 1 shows a quick-acting triple valve apparatus in which the emergency mechanism is independent of the movements of the triple valve, which is in the "release" position. Reduction of pressure in the trainpipe 60 causes the piston 4 to open the graduating- valve 7 and then move to the right of the charging-ports 11, drawing the valve 5 to the right until the port 25 registers with the port 19 leading to the brake cylinder. The pressure in the chamber 34, connected as shown to the space 8, now falls, and the spring 37 moves the diaphragm 30, closing the valve 31 and opening the valve 32, and reservoir air flows through the passages 13, 94, 93 into the chamber 16 and thence to the brake cylinder through the ports 25, 19, 26. When the pressure in the chamber 16 falls slightly below that in the train-pipe, the piston 4 moves to the left, to close the valve 7 and uncover the ports 11, and, by raising the pressure in the train pipe, air passes through them past the weighted valve 15 to the passage 13 and the auxiliary reservoir. The brakes are released by raising the pressure in the train-pipe sufficiently to return the diaphragm 30 to the right to open the valve 31, and close the valve 32, and the air in the chamber 16 is exhausted through the passages 93, 90, 91, 92, 22, 21, 24, and 20, and then the piston 3 moves to the left and the brake cylinder exhausts through the passages 26, 19, and 20. Fig. 2 shows a quick-action triple valve in which " service " applications are made during the first portion of the stroke of the piston 4, but, when this piston forces back the buffer 63, the emergency mechanism 67 comes into action. Air from the trainpipe is allowed to enter the chamber 8 through the passages 61, 62, and the valve 32 is controlled by the piston 43, the stem of which has a valve 45. When the piston 4 is in the position shown, the brakes have been set, the piston 43 is balanced, and the ports &c. 90, 91, 92, 22, 21 are at atmospheric pressure. As the pressure in the passage 35 is increased, the diaphragm 30 opens the valve 31, and the pressure on the right of the piston 43 is vented through the ports and passages 47, 48, 90, 91, 92, 22, 21, 24, and 20 until the valve 45 is opened, when the piston 43 moves quickly to the right and stands between the ports 47, and the spring 33 closes the valve 32. Air in the cavity 16 now exhausts through the passage 93, one of the ports 47, round the piston 43, through the other port 47, past the valve 45, and thence by the ports and passages 90, 91, 92, 22, 21, 24, 20 to the atmosphere. The triple valve now moves to the left or position of release, and the port 21 is again opened to the cavity 16, and air flows back and re-balances the piston 43, and the valve 32 is opened. The brakes may be released by hand by opening the valve 50, when the air to the right of the piston 43 escapes through the ports 47, passage 48, and valve 50 to the atmosphere, and the action described is repeated. Fig. 6 shows a modification, in which the re-charging and releasing appliances are arranged in a casing bolted to the triple-valve casing. Fig. 11 shows a valve for regulating the pressure in the train-pipe 88. Normally the valve 86 is held open by the spring diaphragm and piston 81, but, when the maximum train-pipe pressure is attained, the piston is depressed, and the spring 89 closes the valve 86. In cases where the train pipe and auxiliary reservoir are accidentally allowed to attain the pressure in the main reservoir, ordinary ventings of the train pipe would not allow the valve 31, Figs. 1 and 2, to close, and the brakes would not set. To obviate this, a secondary slide 105, Fig. 12, is fitted to the back of the slide 5, and port 106 in it controlled by the valve 7 registers with the port 25 in the brake-setting position. The main valve 5 has two cavities 24, 107, Fig. 13, and two small ports 108, 109 in the top of the valve lead respectively into these cavities. The slide 105 has a cross port 110. When the pressure is reduced to set the brakes, the cross port 110 is to the right of the ports 108, 109, and there can be no communication between the cavities 24, 107, and consequently none between the ports 20, 21, and the brakes may be set with certainty whatever the pressure in the train-pipe and reservoir. In a modification, the valve 7 is dispensed with, and the secondary slide 105 performs the graduation function.