GB191411802A - Improved Automatic Speed Control Apparatus for Railway Trains. - Google Patents

Abstract

11,802. Howe, W. K. May 13. Track apparatus actuating signals on trains and for stopping trains.-The brakes of a train are controlled by ramps at the signals in such a manner that the speed of the train, after passing a caution or danger signal, must be below a predetermined speed for that part of the track, and if this speed is exceeded, the brakes are applied automatically, but otherwise the driver maintains control. Fig. 1 is a diagram showing the train equipment and a fixed track ramp 34, which, by means of a three-way switch 87, 88, can be connected to either the positive or negative pole of a battery 89 or can be insulated. A normally closed circuit on the train, from battery 22, through the coil 20, contact 25 on the armature 26, lead 29, and contact 30, maintains the armature 26 and its associated parts in the position shown when running between ramps. The armature 26 supports, by a lug 36, the pivoted bar 38, on which is pivoted a cam 40 and a wheel 41, counterweighted to return to the position shown and provided with teeth to engage the worm 7, driven from a train axle so as to rotate the cam 40 and allow the bar 45 to drop gradually when the coil 20 is de-energized. The bar 45 supports a bar 47 pivoted thereon, and normally the circuit is made at contact 50 to energize the brake-valve holding-magnet 66,- and the circuit to the bell 61 is open. At a line-clear signal, the ramp 34 is connected to the battery 89, so that, when the switch 30 is opened by contact with the ramp, a circuit is made from earth through the two batteries 89, 22 in series to the coil 20, and the apparatus on the train is unaffected. At a caution signal, the batteries 89, 22 are in opposition, and no effective current passes. The armature 26 then falls away from its core, and the lever 38 drops and puts the wheel 41 into gear with the worm 7. A circuit is made to the bell 80, but is quickly broken by the energizing of the coil 54 from the battery 89, which lifts the bar 38 and permits the wheel 41 to gravitate.to normal position. At a danger signal, the coil 20 is de-energized, but the coil 54 is not energized as at a caution signal. In both these cases, the wheel 41 is rotated, and the bar 45 is gradually lowered, carrying the bar 47 with it until the latter bar meets an arm 18 moved by the centrifugal governor; the position in which contact is made is thus dependent upon the distance the train travels past the ramp and the speed of the train. When the arm 47 is stopped by the arm 18, the bell 61 is energized, and shortly afterwards the brakevalve magnet circuit is broken, and the brakes are applied and the armature 68 makes the circuit to a recording-device 75. The driver is able to keep the apparatus out of operation by sufficient reduction of speed.