Patent GB-191202455-A (GB)
Title: Improvements in and relating to Fluid Pressure Braking Apparatus.
Inventor: TURNER WALTER VICTOR
IPC: B60T13/66
Filed: 1912-01-30
Granted: 1912-09-05
Abstract: 2455. Turner, W. V. Aug. 23, 1911, [Convention date]. Fluid-pressure.-In fluid-pressure braking- apparatus having electric control, the main distributing-valve is operated pneumatically by means adapted to be controlled either electrically or pneumatically and arranged so that the pneumatic control can be effected in the usual manner in case of failure of the electric control. The distributing-valve mechanism is, moreover, provided with a valve device which operates automatically to effect an emergency application of the brakes when the train-pipe pressure falls below a predetermined amount; with a local-venting valve controlled by a valve device which is subject to the opposing pressures of the brake cylinder and the flow of fluid to the brake cylinder in emergency applications; and with means for cutting the electric service or emergency means, or both, out of action. In a modification, the distributing-valve is provided also with means, operated in emergency applications, for supplying fluid from the main reservoir to the brake cylinder, and for blowing- down the auxiliary-reservoir pressure so as to facilitate the subsequent release of the brakes, and with a chamber for controlling the time during which the local-venting valve remains open. The form of distributing-valve shown in Figs. 6 and 8 is connected at S to the auxiliary reservoir, at 29, 95 to the brake cylinder, at 112 to the train-pipe, and at 73 to a supplementary reservoir, and comprises a main valve 5, emergency valve 11, local-venting valve 15, and electric release, service, and emergency valves 45, 47, 48 operated by magnets 44, 46, 37 respectively. The terminals 51, 53, 55 of these magnets are connected respectively, for example, by train wires 50, 52, 54 to contacts 65, 66, 67 on the driver's valve shown in Figs. 2 and 4. The other terminals 61, 62, 63 of the magnets are connected by a common return train wire 57 to one pole of a battery or other source of current 58, the other pole of which is connected by a train wire 56 to a contact 64 on the driver's valve. The magnets are operated by a movable contact 69 on the driver's valve, the arrangement being such that the positions of the driver's handle for the electric control coincide with the positions for the corresponding pneumatic control. The valves are shown in the release position in Figs. 2 and 6, in which fluid from the main reservoir at 121, Fig. 2, flows by ports 123, 124 to the trainpipe, and thence by ports 112, 79, Fig. 6, valve 49, and ports 43, 80, 81 to a passage 82, from which it flows to the emergency valve chamber 9, feed groove 83, and chamber 84, and also by a passage 7 to the main valve chamber 2, charging the auxiliary reservoir by way of a valve 71 and ports 70, 72, and the supplementary reservoir by the port 73. The brake cylinder is connected to atmosphere by way of ports 29, 105, 97, 99, 101, 110, 111, the release valve 45 being open since the magnet 44 is de-energized. For the service application, the driver's valve is moved to the position shown in Fig. 4, in which the reduction in train-pipe pressure is effected pneumatically by the escape of fluid from above the equalizing-piston 127 by ports 129, 130, 131, and electrically by the engagement of the contact 69 with contacts 64, 65, 66, which energizes the magnets 44, 46 so as to close the valve 45 and open the valve 47, whereupon the train-pipe is vented into the brake cylinder by way of ports 112, 79, valve 49, ports 113, 86, 88, valve 47, port 93, valve 94, and port 95. In either case, the reduction is communicated to the chambers 2, 9 and causes the main valve piston 3 to move its full traverse to the left, but is not sufficiently rapid to effect movement of the emergency valve 11. The piston 3 moves the graduating- valve 6 to close the port 72 and open the port 96 to the auxiliary reservoir, and afterwards moves the main valve to bring the port 96 into line with the brake-cylinder port 95. For an emergency application, the driver's valve is rotated beyond the position shown in Fig. 4 until the train-pipe is vented directly by ports 124, 133, 131, and the contact 69 connects the contacts 64, 67, thereby energizing the magnet 37 so as to open the valve 48 and close the valve 49, thus venting the chambers 2, 9 by ports 7, 82, 81, 86, 113, valve 48, and exhaust port 114. The reduction of pressure in this case is sufficiently rapid to operate both the main valve 5 and the emergency valve 11, as shown in Fig. 8, and fluid is supplied from the auxiliary reservoir to the brake cylinder as before. In addition, owing to the movement of the emergency valve, the lower side of a valve 21 is vented to the brake cylinder by ports 24, 115, 116, 117, 29, and the supplementaryreservoir pressure, which has access to the top of the valve 21 by ports 73, 76, 77, 78, 20, opens the valve 21, thus reducing the pressure at the underside of a valve 17. Fluid from the auxiliary reservoir, which has access by a port 19, then opens the valve 17 and passes by ports 20, 26 to the lower side of another valve 27, which is in communication at its upper side with the brake cylinder and opens, allowing fluid to pass by ports 118, 95 to the-brake cylinder. When the brake-cylinder and auxiliary-reservoir pressures become equalized, the valve 17 closes and allows fluid to flow from the supplementary reservoir bv ports 73, 76, 77, 78, 20, 26, 118, 95 to the brake cylinder, Fluid from below the valve 27 flows also through a port 31 and operates pistons 14, 33, the former of which opens the valve 15 to vent the train-pipe by ports 112, 92, while the latter closes an electric switch 35, 36 which maintains the emergency magnet energized whatever may be the position of the driver's valve. When final equalization of pressures occurs, the valves 21, 27 are closed by their springs, and the chambers of the pistons 14, 33 are vented bv ports 90, 91, 92 so as to close the valve 15 and open the switch 35, 36. A graduated release may be obtained electrically by moving the driver's valve to release until the desired reduction in pressure has been made, and then moving the valve back to lap position, in which the magnet 44 alone is energized, thus closing the release valve 45. A graduated release may be obtained pneumatically after service applications by the same movements of the driver's valve, the main valve being first moved to the release position, Fig. 6, but afterwards returned sufficiently to lap the brake-cylinder exhaust ports by pressure from the supplementary reservoir flowing through ports 73, 70, 72. If the train-pipe pressure falls below a predetermined amount, a valve 38, which communicates at its lower side with the train-pipe and at its upper side with an exhaust port 40, is closed by a spring 39, whereupon the chamber 9 is exhausted by ports 82, 81, 40, and the valve 11. moves to effect an emergency application. The ports 86 are formed in a cap 87 in such a way that by adjusting the cap either of the valves 47, 48 may be cut out of action. In order that greater resistance may be offered to the movement of the valves 5, 11 to the application position than to their return to release position, each valve is provided at the underside with a cavity which is vented during the preliminary movement to the application position, and is supplied with fluid during the first part of the return movement. Fig. 9 shows a modified form of distributing- valve, in which the action for service applications is the same as before, except that the fluid which flows from the auxiliary reservoir to the port 95 afterwards passes to the brake cylinder past a valve 136 and by ports 139, 140, and the port 95 is fitted with a safetyvalve 135 for limiting the brake-cylinder pressure. In emergency applications, however, the auxiliary-reservoir pressure merely blows out through the safety-valve 135 and does not pass to the brake cylinder, since the valve 136 is closed due to the venting of the left side of the piston 137 to atmosphere by ports 159, 156, 157, the emergency valve 11 having moved to its uppermost position. Fluid also flows from the chamber 84 by a passage 150 to a piston 149 so as to open a pilot valve 147, thereupon venting the right-hand side of a valve 141 by a port 145, valve 147, and exhaust port 148. Main-reservoir pressure from the connexion 143, acting on the other side of the valve 141, then opens this valve and passes by the port 140 to the brake cylinder. The fluid in the passage 150 also opens a valve 153 and passes by the port 31 to pistons 14, 33, which operate the local-venting valve 15 and switch 35, 36 as before, except that the action is modified by a chamber 151, into which the pressure in the chamber 84 equalizes.