Patent GB-135170-A (GB)
IPC: B60T13/36
Abstract: 135,170. Automatic Straight Air Brake Co., (Assignees of Neal, S. G.). Nov. 13, 1918, [Convention date]. Fluid-pressure. - Valve mechanism, more particularly for brake apparatus in which in service applications the brake cylinder is connected to the train-pipe and a train-pipe reservoir and in emergency applications to this reservoir and an emergency reservoir, comprises a pilot valve K, controlled by train-pipe and brake cylinder pressures opposed to a pressure unaffected by service applications, and adapted (1) to vent the chamber 4 of the main valves I, N to the brake cylinder whereby the valve I is moved to service position by the train-pipe pressure in the chamber 2, (2) to return the valve N to lap position when the brake cylinder pressure is proportional to the train-pipe pressure reduction, (3) with a manually-operable valve M in one position, to admit air from the emergency reservoir to the chamber 4 and the train-pipe to effect a quick release of the brakes, and (4) with the valve M in another position, to exhaust the brake cylinder to an extent proportional to the increase in train-pipe pressure. In emergency applications, the train-pipe is vented to atmosphere by a valve J. An abutment 9 moves the valves I, J, N to emergency position and returns the valves I, N in graduated release operation. Charging of the emergency reservoir is not effected until the service reserver is fully charged. If the train-pipe and service reservoir pressure falls to a low point in service applications, the valves I, J, N are moved to emergency position by a pilot valve L. The train-pipe is connected at H. Fig. 2, the train-pipe reservoir S at 120, Figs. 4, and 4a, the emergency reservoir E at 146, and the brake cylinder B, C at 130. The pilot valve K, Fig. 3, is actuated by a lever 57 pivoted at 57<1>, and abutments 46, 49, 50 which move together under the action of the pressures in chambers 47, 51. 53<a>, 54. Chamber 47 is constantly connected by passage 48 to chamber 2, Figs. 2 and 4<a>, and thence to the train-pipe except in emergency applications. Chamber 51 is directly connected to the brake cylinder by a passage (not shown). Chamber 53<a> is connected to atmosphere by the pasage 53 and main valve ports 124, 125, 126, Figs. 4<a> and 11, except in emergency applications, when it is connected to the reservoir E. Chamber 54 is always connected to the reservoir E. The stem 27 of the main valve, Fig. 2, has a cross-head 28 adapted to be engaged by shoulders 31, 30 on the stem 29 of the emergency piston 9, which is about double the area of piston 7. The chamber 2 is open to the train-pipe H except in emergency application by passages 12, 15, 16 and emergency valve port 41. In the charging and full-release position shown, and with the release-governing valve M in quick-release position, as shown, the main valve chamber 4 is connected to the train-pipe by passages 12, 13, ports 14, 93 of main valve I, passage 94, Fig. 4, ports 95, 96 of valve M, passage 100, Fig. 4, passage 102 of pilot valve K, passages 104, 106, Fig. 4, and ports 107, 109 of main valve I. The chamber 3 of valve I is connected to the trainpipe by the extension 115 of port 93, and the quick-action chamber 10, Fig. 2, connects with the train-pipe by leakage past the piston 9 and also by the chamber 3, ports 116, 118 of valve I, passages 119, 123, Fig. 4<a>, past check valve 122, Fig. 21. The train-pipe reservoir S is also connected at 120 to the passage 119 and thus to the train-pipe. When the reservoir S is fully charged and the pressure in chamber 2 is no longer superior to that in chamber 10, the spring 34 moves the piston 7 to the left until the shoulder 35 abuts against a stop, thereby moving the graduating-valve N to register ports 140, 142 so that the train-pipe air can feed to the reservoir E from chamber 4 by passages 25, 141, 142, check valve 147 and port 143 to passages 144, 145, 146, Fig. 4. This delayed charging of the reservoir E prevents its being overcharged by an abnormal increase in train-pipe pressure. Overcharging of the reservoir S is prevented since the excess pressure in the chamber 10 moves the valve I to service position, admitting air from this reservoir to the brake cylinder, which is, however, immediately exhausted by the movement of the pilot valve to release position. In the full-release position, the brake cylinder is exhausted through passage 130, Fig. 4, ports 127, 132 of valve I, passage 134, Fig. 4<a>, and ports 136, 138 of valve M, as well as through passage 151, Fig. 4, and ports 149, 169 of pilot valve K. When a service reduction of train-pipe pressure is effected, the pilot valve is moved by the emergency-reservoir pressure in chamber 54, Fig. 3, to cut off the chamber 4 of valve I from the train-pipe and to vent it to the brake cylinder by ports 109, 107 of valve I, passages 106, 104, Fig. 4, pilot-valve passage 149, and passages 151, 130. The main valve I therefore moves to service position, in which air flows from the train-pipe to the brake cylinder by ports 14, 92, 157, 156, 159, 127 of valves I, N and passage 130, Fig. 4, and from the reservoir S to the brake cylinder by ports 118, 160, 161, 162, 92. The chamber 4 is at this time conneeted to the train-pipe by the ports 155, 154, 157, 14, and the consequent approximate equalization of the pressures in chambers 4 and 2 arrests the movement of the valve I in the service position. When equilibrium of pressures in chambers 47 and 51, Fig. 3, is reached, the pilot valve K assumes the lap position, closing the vent of chamber 4 through this valve and enabling the pressures in chambers 2 and 4 to equalize, so that the graduating valve N is moved to the right by the spring 158 to close the passage 159 to the brake-cylinder port 127. Fig. 5. In the service position of the valves, the chamber 3 is connected to the reservoir E through the valve M and the port 93 of the valve I to hold the valve I to its seat. When the train-pipe pressure is raised, the valve M being in quick-release position, the reservoir E is conuected to the chamber 4 by passages 146, 153, Fig. 4, past a check-valve 114 to port 110 of valve M, thence to port 95, passage 100, through port 102 of pilot valve K which is in release position, Fig. 3, passages 104, 106, and ports 107, 109 of valve 1. The valve I is thus moved to full-release position, Figs. 2 and 5, permitting emergency-reservoir air to flow also to the train-pipe from port 95 through passage 94, Fig. 4, and ports 93, 14 of valve I. The brake cylinder then exhausts by way of mainvalve port 132 through port 138 of valve M, and also through the port 169 of the pilot valve K, as described above. If the valve M is manually set for graduated release operation, the conditions are as follows :-(1) The ports 136, 138 are blanked so that the brake cylinder exhausts only through the pilot-valve port 109, which is closed when the exhaust is proportional to the increase in train-pipe pressure; (2) the port 110 is blanked so that emergency reservoir air cannot flow to the chamber 4 and the train-pipe; (3) the ports 167, 95 are connected whereby air is supplied from the train-pipe to the chamber 4 in release by chambers 2, passage 48, Figs. 2 and 4<a>, ports 167, 95, passage 100, Fig. 4, the pilot valve K, and the valve I. The train-pipe is connected to the chamber 10, with the valves I, N in the service lap position, through the valve I and passage 118 and if the rise in trainpipe pressure is rapid enough, the pressure builds up in chamber 2 against that in chamber 10 and the valves I, N are returned to release position by the abutment 9, but if the train-pipe pressure is slowly increased these valves are not moved. In the service lap position, the groove 140 is slightly open to port 142, so that air can feed from the chamber 4 to the reservoir E to maintain the pressure therein, the valve N being momentarily returned to application position to replenish the chamber 4 if the pressure therein is appreciably lowered from this cause. If an emergency train-pipe pressure reduction is made, the pressure in chamber 2 drops sufficiently below that in the chamber 10 to permit piston 9 to move, to the left, the stop 30 engages the cross-head 27, and piston 7 and the emergency valve J, Fig. 2, are moved to their extreme left-hand positions. This movement of the valve J vents the train-pipe to atmosphere hy passages 12, 16, 40, 39. The valve I con. nects the emergency reservoir to the brake cylinder by passage 146, ports 165, 164, 172, chamber 3, port 127, and passage 130. The trainpipe reservoir air also feeds into the brake cylinder, if not previously equalized by a service application, by passage 119, Fig. 4<a>, past the check valve 132, quick-action chamber 10, passages 89, 90, the port 91 of valve J, chamber 5, and ports 41, 173 of valve J, the port 173 being directly connected to brake-cylinder passage. 130, Fig. 4. The chamber 82 of the emergency pilot valve L, Fig. 3, is connected to the chamber 3 by the main valve I in emergency applications, so that the valve L is maintained in the position shown and provides a further connexion for the reservoir E with the brake cylinder by passage 146, ports 165, 164, 139 of valve I, passage 78, Fig. 4<a>, chambers 76, 79<a> of the valve L, and passage 89, and thence, as just described, to brake-cylinder port 173. The reservoir E also connects with the quick-action chamber 10 by passage 89. When pressures in chambers 2 and 10 equalize, the spring 38<a> will move back the valve J until the shoulder 31 engages the cross-head 38, thereby blanking the train-pipe vent port 39, but leaving open port 91 and connecting chamber 2 with port 173 by port 176. The port 122a in check valves 132, Figs. 4a and 21, permits the emergency reservoir and brake-cylinder pressures slowly to equalize down into the train-pipe reservoir. The chamber 4 is vented to the tr