Patent GB-190723749-A (GB)
Title: An Automatic Stop for Railway Engines and Trains
Inventor: HAYDOCK EDWARD
Filed: 1908-04-28
Granted: 1908-12-31
Abstract: 23,749. Haydock, E. April 28, 1908. Stopping engines and trains ; recording signals.- Means are described for stopping trains, by automatically applying the brakes and shutting off steam, when the driver passes a signal at danger or takes a curve at too high a speed. Two pivoted track contacts 1, Fig. 1, one for each direction of running, are connected across the track by drawrods 5 and a fulcrum lever 6, and the draw-rods are connected to the signal-rods so that the contacts are drawn into a vertical position when the signal goes to danger. At junctions, the contacts may be connected to more than one signal, and balance weights 7 are provided for all contacts. If the signals are operated pneumatically the same power may be used for the contacts, and if electrically the contacts may be electro - magnetically controlled; in some cases the contacts may be independently controlled. The contacts 1 when in the vertical position are adapted to operate the triplever 8, Figs. 2 and 3, of a passing engine. The lever 8 is connected to a crutch-plate 23, which operates, when the lever is moved, to release the piston-rod 12 attached to the piston 10 of a dashpot 9, which piston is normally held back against the spring 11 by the tapered lug 28 held by a dashpot 24. The piston-rod 12, when released, operates through a lever 20 to open a valve 21 in the brake pipe 22, and also, through a bell-crank lever 13, to depress a rod 14, which passes up through the smoke-box and is connected to a lever 16, Fig. 2, keyed to a cross-shaft 17, to which are fastened two levers 18 which operate two quick stop valves 19 to shut off steam. The piston-rod 12 may be re-set by the driver by means of the rod 25 and connexions to the foot-plate. Levers 8 may be provided on both sides of the engine, and the pivoted stops may be replaced by tapered ramps, in which case rollers are provided on the levers 8, which are normally held vertical by springs. A rod connected to the rod 12 opens a cock to cause a punch to record on a chart in the cab or guard's van the time of operation of the apparatus. The brakes and cut-off may alternatively be operated pneumatically direct from the contact-lever. To prevent drivers from taking curves and dangerous parts of the line at too great a speed, track contacts are placed in advance of the curves, and are controlled by falling racks or weights which pull the contact clear after a definite interval, the falling weight being released, and the contact elevated, by the train passing a contact in advance. If the speed is too great, the train will be stopped by the operation of the lever 8. Alongside the track is mounted a cylinder 98, Fig. 40, in which works a piston 99 having two spring-held valves 100 which open to admit air on the up-stroke of the piston. An outlet controlled by a regulating cock 113 is provided at the bottom of the cylinder, and the piston is connected to a pinion 102 which gears with a fixed rack 104 and a movable rack 105, which slides in guides and is weighted by weights 109 which move in a well. The front side of the rack is provided with a vertical projecting cheek 114 under the inclined end of which a roller 120, mounted on a cross-head, is normally held by the dash-pot 125, the piston of which is connected by a rod 122 with the cross-head. The back of the rack 105 has a projection 115 which, when the rack reaches the end of its travel, contacts with an arm keyed to a cross-shaft, and through similar connexions to those shown in Fig. 1, raises the track-contacts 1 to the vertical position. The rack is relea ed by the train passing over a ramp 138, Fig. 42, placed in advance of the stops 1. The depression of the ramp by the first wheel flange pulls over the lever 146 together with the levers 148, 149 which move in the slots 150, 151. The lever 149 is connected by rodding to the crosshead carrying the roller 120, which is thus pulled from under the cheek 114, allowing the rack to drop ; the time of falling is controlled through the cock 113, according to the distance between the contacts 1, 138 and to the allowable speed over the section. The rack 105 and the piston 99 are wound up by the train-wheels passing over treadle 127. Each wheel depresses this treadle against the spring 129, and the movement is communicated through levers 128, 130 and a free-wheel mechanism to a pinion 134, which gears with a rack 156 mounted on the rack 105. The rack is thus raised until the roller 120 passes under its inclined end, when the rack 156 clears the pinion 134 and at the same time a projection 160 contacts with the end of the lever 130 and holds the treadle 127 down so that no further actuation is obtained. To prevent a second operation of the mechanism by the wheels passing the treadle 138, a long locking treadle 139 is provided, which always bears a wheel of a passing train and, when depressed, moves over the lever 147 and lifts the rod 149 clear of the rod 146 and at the same time holds the treadle 138 down through the lever 148. When the train has passed, the dashpots under the long treadle re-set the mechanism ready for actuation by the next train. The cock 113 may be locked to prevent tampering therewith. The stopping mechanism may alternatively be operated by pneumatic means, as shown in Figs. 46 and 48, in which there are two cylinders 170, one behind the other, having two pistons 171 in each cylinder, the rods of which are connected by links to the long treadles 172. The cylinders have suitable end inlets and also inlets 176 which the pistons 171 just clear when at the outer end of their stroke. The two cylinders 170 are made in one casting with a cylinder 173 provided with a piston 174, the rod of which is connected to the rod 121, which as before, operates to release the rack 105 by pulling clear the roller 120. The cylinder 173 is connected with the cylinders 170 by a port 177 which opens from the centre of the lower to the end of the upper cylinder, so that when the long treadle is depressed by the wheel flanges, the pistons 171 are forced to the centre where a very small clearance is allowed. Air is thus forced into the cylinder 173, and the piston 174 is pressed back and the rack 105 released, the excess of air escaping through the port 178. The pistons are held in the central position until the train passes off the treadle 172. The rack 105 and the piston 99 are replaced as the train passes over a similar long treadle 185 to which the pistons 181 of two similar cylinders 180 are connected. The ports 192 at the middle of the cylinders 180 are connected to a pipe 186, so that, when the treadle is depressed, air is forced into the cylinder 188 and the piston 187 and the attached piston 99 are forced up until the port 191 is uncovered, the stroke of the rack being completed, as before, by the engagement of the roller 120 with the inclined end face of the projection 114. The cylinders may be placed vertically and the stroke of the pistons increased by multiplying the levers operated from the treadle shaft. Two or more consecutive pairs of re-setting treadles and cylinders may be used, and the air forced therefrom into a common receiver.