Patent GB-353502-A (GB)
Title: Improvements in or relating to train control systems
IPC: B61L3/12
Filed: 1930-04-23
Abstract: 353,502. Fluid - pressure brakes. ASSOCIATED TELEPHONE & TELEGRAPH CO., 1033, West Van Buren Street, and HUDD, A. E., 947, West Van Buren Street, Chicago, U.S.A. April 23, 1930, Nos. 12605, 30189, and 33309. Addition to 351,071, [Group XXX]. [Class 103 (i).] The invention is a modification of the train control and cab signalling apparatus of the magnetic induction type forming the subject-matter of the parent Specification. In one form the locomotive receiver apparatus comprises a single armature adapted to be controlled by two pairs of flux collecting plates to mechanically operate a valve, one pair of plates when excited opposing the effect of the other pair when simultaneously excited, while either pair of plates when excited alone will move the valve if the armature is in an appropriate position. In another form the locomotive receiver apparatus comprises two armatures each adapted to be controlled by two pairs of collecting plates to mechanically operate its valve, one pair of plates when excited opposing the effect of the other pair when simultaneously excited, and the valves are arranged to control a device if either valve is operated alone but to have no effect if the valves are operated simultaneously. This second form of receiver apparatus is shown in Fig. 2 (12605/30) and the co-operating track magnets at the distant and home signals in Figs. 3 (12605/30) and 4 (12605/30) respectively. The armature 8 is provided with extra legs 10 so that if the longitudinal plates 5, 7 are excited simultaneously with the plates 5A, 5B the latter will not be able to operate the armature, while if the plates 5, 7 alone are active the armature will be held in its existing position but will not be moved. The armature 9 will be similarly controlled, being prevented from movement if the transverse plates 6A, 6B are excited simultaneously with the plates 6, 7. The armature 8 accordingly is moved only if a transverse track magnet acts alone and the armature 9 if a longitudinal track magnet acts alone. At a point 200 yards in advance of a distant signal there is a central longitudinal permanent magnet 1 and spaced therefrom is a transverse electromagnet 2 energized, if the signal is at clear, by the train completing a track circuit. At a clear distant signal, therefore, the longitudinal permanent magnet 1 will move the armature 9 to open its slide valve 19 but will merely hold the armature 8 ; after an interval the transverse electromagnet 2 will move the armature 8 to open its slide valve 18 but will merely hold the armature 9 which however is in its operated position. The action on the train is that a whistle signal is given which is automatically stopped; the opening of armature slide 19 allows air to enter the receiver casing 35 and vacuum system through a whistle 21 but as the other armature slide valve 18 is also opened shortly afterwards the vacuum above two pistons 13, 14 of a cancelling device is destroyed so that the pistons descend and both acting on a lever 28 pivoted on a plunger 12 cause the latter to connect a vacuum supply through an opening 29 and port 30 to the armature resetting pistons 38, 39 which thereby close the slide valves 18, 19. When the distant signal is at danger, the electromagnet 2 is not energized and only the armature 9 will be operated, the result being that a brake controlling valve 17 is actuated by the unbalancing of the vacuum in two chambers 15, 16 and opens the train pipe 23 to atmosphere through a siren 20 ; as only the one piston 13 of the cancelling device is operated the lever 28 merely turns idly and it is necessary to depress the plunger 12 manually if the siren signal and braking is to be cancelled. At a home signal the permanent and electromagnets 3, 4 lie over each other so that if the signal is at clear the armatures 8, 9 are not operated since the holding plates are energized simultaneously with the operating plates; if the home signal is at danger the action is the same as described above at a distant signal at danger. In the train control and signalling apparatus shown in Figs. 1 (33309/30) and 2 (33309/30) the armature 124 opens a slide valve 125 when the pair of flux collecting plates 120, 121 are excited by a longitudinal permanent magnet on the track and closes the slide valve 125 when the other pair of plates 122, 123 are shortly afterwards excited by an energized transverse electromagnet. The opening of the slide valve 125 opens the pipe 110 to atmosphere so that a diaphragm 103 rises to operate a lift valve 105 to open the train pipe 132 to atmosphere, but, on the armature slide valve closing, vacuum builds up in the pipe 110 through a restricted orifice 111 and after a short time the diaphragm 103 descends to close the lift valve; a horn 134 in the pipe connection to the lift valve accordingly sounds for a short time only. At a danger signal the transverse electromagnet is not energized so that, unless the armature is reset by manually depressing a plunger 113 to momentarily depress a diaphragm 138 which acts on the armature, the train pipe continues to be open to atmosphere and a siren 136 (slow acting by reason of its spinning mass) sounds indefinitely and is accompanied by a brake application. The lift valve 105 may be shut down by means of a screw spindle 133. At a home signal at clear the armature is not moved since both pairs of collector plates are excited simultaneously. The train control and signalling apparatus shown in Figs. 1 (30189/30) and 2 (30189/30) comprises a receiver element similar to that shown in Figs. 1 (33309/30) and 2 (33309/30), the resetting however being effected by depressing a valve 53 to admit vacuum from a reservoir 63 to the underside of a resetting piston 50 having a plunger to act on the armature. At a clear distant signal on the opening of the slide valve 125 a rapid acting valve 65 of a "clear signal device" 64 is opened by its spring 66 to give a large opening to atmosphere so that the vacuum in the piping is quickly destroyed and a valve 68 is therefore immediately moved forward by a spring 67 and its stem 71 presses valve 65 to its seat again. Since the distant signal is at clear, the slide valve 125 is soon afterwards closed and vacuum is restored by the connection 91 but, due to the restricted orifice 59, only at a slow rate so that the valve 68 in its slow return opens the port 69 for an interval during which the whistle 70 sounds. A brake control valve 57 is not actuated as a restricted orifice retards the action. With a home or distant signal at danger however the piping would continue open to atmosphere and after a short time the brake control valve would open the train pipe 80 and cause a braking accompanied by action of a siren 61. The braking and siren signal may be cancelled by the plunger 53 which, in addition to resetting the armature as before described, at the check valve 73 applies vacuum from the small reservoir 63 to the piping so that the valve 68 of the " clear signal device " 64 returns quickly and the whistle is not sounded. At a home signal at clear the receiver armature is not actuated and no cab signal is given. To prevent the cancelling plunger being effective if wilfully held down it may be arranged to open the vacuum piping to atmosphere by means of a port 41, Fig. 2 (12605/30), or a small orifice 117 may be provided in the plunger cylinder, Fig. 2 (33309/30), or the vacuum reservoir 63, Fig. 1 (30189/30) may be only of sufficient capacity for one resetting operation at a time.