Patent GB-190710455-A (GB)
Title: Improvements in Automatic Apparatus for Stopping Trains.
Inventor: MCCOLLUM JAMES HARRY KEIGHLY
Filed: 1907-05-04
Granted: 1908-06-04
Abstract: 10,455. McCollum, J. H. K. May 4. Brakes.-Mechanical track contacts, normally in a 'danger' position, engage a pivoted lever on the engine and move it to either of two operated positions so as to actuate valve apparatus to apply the brakes, the lever being held in its operated position by pneumatically-controlled latches until the train is either stopped entirely or slowed down to a predetermined speed so as to release the latches and to allow the lever to be replaced either by hand or by automatic means. Miniature signals and brake indicators are provided on the engine, and also means for operating the throttle valve and a whistle. Arrangements of valves are described for working with the locomotive running tender-foremost, for working trains having a locomotive at both the front and rear ends, and also for working trains having a locomotive with vehicles in front and in the rear. The engine contact lever may be connected to the valve by a link-work to compensate for variations in the height of the vehicles under different loads. In the case of electric railways, the lever may serve to open the power circuit. Several forms of track contact are described, all being in the form of an inclined plane which may be fixed or may be moved from the normal danger' position to the 'clear' .position either mechanically, electrically, or pneumatically. Figs. 2 and 3 show a pivoted inclined striker-plate 10 supported on a frame 8 carried on arms 2, 3, so as to overhang the track rails. The position of the frame 8 is adjusted so as to set the plate 10 in line with the lever 48 of the valve apparatus 38 carried by the locomotive. The plate 10 is connected by links to the piston 16 of the cylinder 15, to which air is admitted by the pipe 21 so as to lift the plate 10 clear of the lever 48. The cylinder is enclosed by a cover 19. The air supply may be controlled by any suitable means, such as electromagnetically-operated valves controlled by track relays. Similar inclined strikerplates may be actuated by electric motors through rack and pinion gearing, or by wires and rods operated manually, and, if required, two such plates may be arranged together to form a double incline, and the track contacts may be arranged above, below, or at the side of the locomotive. The valve apparatus 38, shown in detail in Fig. 8, is actuated by the lever 48 on the spindle 47 carrying disks 51, 53, which are moved to one of two operated positions on each side of the normal position shown, according to the direction of movement of the locomotive and the extent to which the lever 48 is moved. The disks 51, 53 have ports registering with similar ports in the dividing-partition 40 and in the outer wall 42 of the chamber 38, a spring serving to hold the disk 53 in good contact. A rotary latch 58 on the spindle 47 having two notches separated by arcs of different length engages two sliding pieces 63, 65, which serve to hold it, when turned, until these pieces are withdrawn. The latch-bolt 63 has a forked end in which a lever 84 engages, said lever being actuated by the pistons in the cylinder 69. The cylinder 69 has a reduced end 70 provided, as is also the larger end, with a double piston. The inner piston is solid while the outer piston has a small hole through which air passes to the reservoirs 75, 76. Both ends of the cylinder are connected to the train-pipe 87, a check-valve 88 being fitted on the supply to the narrow end of the cylinder which is, therefore, always subjected to pressure. While the train-pipe is in its normal state, the pressure in the larger end of the cylinder causes the latchbolt 63 to press against the latch 58 so that, when the lever 48 is turned by contact with the track obstacle 10, the latch bolt enters one of the notches 59, 60 and the valve 51 is kept open until the pressure in the train-pipe is reduced, when the pistons of the cylinder 69 are replaced by the pressure on the smaller piston. The small holes in the front pistons cause the replacement to be performed slowly. Alternative and preferable means for controlling the latches are described which are actuated by aircompressors or vacuum-pumps driven from a rotating axle of the train and controlling spring-pressed pistons in cylinder valves supplying cylinders for actuating the latch-bolts. The delivery pipes from the pumps have a small hole arranged so that, as the train slows down to a given speed, the pressure on the pistons of the valves is just overcome by a spring. Two sets of controlling-valves are arranged to operate at different speeds, so that, when the valve arm 48 has been turned to its second operated position, the train must be slowed down to a greater extent before the latch can be released. The cylinder 133, shown in detail in Fig. 18, serves to replace the lever arm 48 by means of the crank 130 on the spindle 47 when the pressure in the trainpipe 135 is sufficient. It also serves as a valve to pass air to the indicators 136, 141, consisting of pressure gauges with a moving pointer and suitably inscribed dials. In the normal position, the indicators are connected to the train-pipe, but, when the valve arm 48 is moved, the piston 132 is depressed and, at the first position of the lever 48 which serves to slow down the train, the gauge 136 is exhausted through a channel in the cylinder wall. The gauge 141 is put to exhaust only when the lever 48 is moved to its second position to stop the train. In order to hold the lever 48 in its operated position until released by a second person other than the engine driver, an electro-magnet 150 may be used to withdraw a latch bolt 65 against the action of a spring, and such electro-magnet may be energized from a source of energy under independent control. A key 155, to be inserted through a sealed opening in the casing, may be used in place of the electromagnet. In order to allow forward or backward movements of vehicles, the valve apparatus, Fig. 8, is duplicated on both sides of the vehicle, and the two valves are connected as shown in Figs. 13 and 14 to the cylinders 163, 164, and the valve 185 is connected to the reversing-lever 190. In one position of this lever, the pipe 191 and cylinder 163 are open to exhaust at the valve 185. The pistons of the cylinders 163, 164, therefore, move towards the cylinder 163, and the train line 167 is connected through a pipe to one of the valves 38. Check valves 195, 396 prevent return of air from the cylinders to the train-pipe 193. On electricallycontrolled vehicles the exhaust valves may be controlled by electro-magnets energized through contacts on the controller handle. The exhaust pipes 197 from the two valves 38 are connected to the valve chamber 214, the piston 217 of which is connected to the piston of the cylinders 198, 199 by a pin and slot. A sudden reduction of pressure in the trainpipe 219 exhausts the larger cylinder 198, and the smaller cylinder, being kept under pressure by the check valve 220, slowly forces the piston 217 to the right and closes the exhaust pipe 197. The slow motion allows sufficient time for a service application of the brakes. In place of the valve 217, an ordinary poppet valve may be used on the pipe 197, this having the disadvantage of closing before a sufficient reduction in pressure could be made if the train-pipe pressure should be low. A piston 224 may be connected to the throttle lever 227 so as to be operated by air from the pipe 197. For the purpose of enabling two vehicles to be operated together and the brakes to be under the control of one, the arrangement shown in Fig. 17 are used. The train-pipe 228 is connected to the engineer's valve 229, which is connected to the reservoir by a pipe 231. Valves 232, 240 serve to cut off one of the three pipes connected to them and to join the other two, stops being fitted to prevent excessive motion. A multiple-way rotary valve 265, out of reach of the driver while the train is in motion, has grooves which connect the various inlets and outlets. The ports 257, 263 are closed when the ports 259, 261 are opened, and vice versa. For ordinary working, the ports 235, 242 of the valves 232, 240 are closed, thus closing one end of the trainpipe and connecting the other end to the train. If the valve 265 is not properly set, the train-pipe will be exhausted through the pipe 247, and air will also flow from the main reservoir or train-pipe to the pipe 274, causing the whistle 273 to sound as soon as the throttle lever is pulled to start the train. Also the cylinder 275 will be exhausted through a small orifice in the valve casing, and the semaphore arm 276 will rise to 'danger.' By suitably arranging the valves, the desired connexions may be made for two vehicles to assist one another and for ensuring proper connexions of the brakes under any conditions. The valve 252 is an emergency valve for use when an engine is pushing a train from behind, and is encased in a destructible cover.