Patent GB-217946-A (GB)
Title: Train control apparatus
IPC: B61L3/22
Filed: 1923-01-23
Abstract: 217,946. Marks, E. C. R., (Clifford International Corporation). Jan. 23, 1923. Electrical systems, automatic; track apparatus actuating signals on trains and for stopping trains.-A primary relay, which may have one or two rotatable coils and' contact members, for controlling a local circuit including signals and train controlling devices, is connected in shunt across the vehicle frame or portions of the track rails, vibration of the armature by jar or shock of the vehicle being thereby damped. The primary relays may be connected through the wheels of the vehicles in shunt to a length of one track rail, or to lengths of opposite rails or may be connected to a front and rear wheel on opposite sides of a vehicle. Fig. 9 shows a relav PR having two moving coils a, b and contact arms arranged so that vibration tending to open the contact at one arm will close the contact at the. other arm. Each coil is in shunt to one track rail. Figs. 9<a> and 9<b> show arrangements to avoid open circuits through the coils of the relay PR on passing insulation joints in the track rails. In Fig. 9<a> each pole of the only relay coil c is connected to two alternate pairs of wheels spaced apart, and in Fig. 9<b> the two coils are connected to pairs of wheels, the lengths of rail shunted by the coils in this case being separated. Fig. 4 shows a system for supply of energy to the track rails of a three position signalling system. The track rails are divided into block-sections provided with track batteries TB - - TB<4> relays T' - - T<5> in the usual manner, and also with additional relays B - - B' the armatures of which reverse the polarity of the current supplied from additional batteries I - - V and I<1> - - V<1> to the rails on opposite sides of the track. Each section is fed through the armatures of the track relays of the section ahead so that a train x in section 3 cuts off the supply from the section in the rear. The relays B<1> - - B<5> of each section are controlled in parallel with the circuit to the rails, so that the train de-energizes the relay B<2> of the rear section thereby reversing the polarity of the current supplied to the section next but one in the rear. The current supplied to the rails does not interfere with the ordinary track circuit, since it travels in the same direction in both rails, thereby affecting the potential of both sides of the track relay to an equal extent. Current is not passed through the rails from the additional batteries until the track relay of the section concerned is de-energized. If the. section ahead is clear, on the train entering a section, a polarized relay PR, Fig. 5, preferably of D'Arsonval type, maintains its armature 17 against a contact 16 on account of the voltage drop along the rails, thus completing a circuit from a. battery VB to a relay SAR, the aimature 18 of which maintains the circuit from the battery VB to a relay GOV. The armature 19 of the relay GOV maintains the circuit of a relay S controlling a " clear " lamp G, and a relay TL is in parallel with the relay S and controls a brake-restraining solenoid 30, in parallel with a relay AR. In a section in which caution conditions prevail, the current from the batteries I and I<1> is reversed, as in section 1, Fig. 4, so that the relay PR on a train entering that section completes the circuit of a signal AYS indicating " caution," and of a relay AY the armature 28 of which bridges the contacts 15, 16 so that the .relays previously energized remain energized thus holding the brakes off, the relay SAR being slow acting so as not to release during the movement of the armature 17. On entering block 2, in which no additional current flows in the rails, the armature 17 moves to a neutral position and if the speed has been reduced to enable a speedcontrolled contact HSL to close, and so to shunt the armature 24 of the relay GOV, the solenoid 30 remains energized so long as the relay TL, which is slow-releasing and arranged to release at a safe distance from the next signal, remains energized. The relay S de-energizes the signal G and a signal Y indicating caution is operated and a signal ARS, indicating a stop signal ahead. If the block be entered with the speed-controlled contact HSL open, the brakes are applied immediately and a signal R indicating danger is displayed. Further reduction of speed to say 4 miles an hour closes a second speed controlled contact LSL which shunts the armature of the relay TL, releasing the brakes and displaying the signals Y, ARS. The relay PR is connected between front and rear wheels of the locomotive. Various means are described for maintaining the relay SAR energized on leaving equipped territory. A plunger p<5>, Fig. 21, may be pressed by hand into contact with a contact p<6> thereby completing a circuit through a magnet p' in shunt with the contact p<1>, of the relay PR so that when this contact breaks, the circuit of the relay SAR will be maintained and the plunger will remain depressed until, on leaving the equipped territory, the relay PR is energized and the contact p' shunts the coil p<7>, causing it to release the plunger p<5>. In a modification the plunger is moved by a solenoid energized by a contact ramp and is held by the circuit as in Fig. 21. It may also be operated mechanically by a ramp. The valve controlled by magnet 30 on the train is shown in Fig. 10. A spring 29<a> moves a core x when the solenoid 30 is de-energized thereby opening a valve Y through link-work f so as to allow air from a pipe 39<a> to force a piston b to operate a valve 19<a>. The valve 19a, Fig. 12, passes air from a pipe 13<x> to a pipe 15<x>, so as to move a piston 46, Fig. 16, thereby venting the train pipe T through graduated ports 42. 43, 44 and 44'. Air also passes from pipe 15<x>, through passages 55, 57 and pipe 51 to operate a piston b<11>, Fig. 17, so as to sever the connection between the engineer's valve and the train pipe, preventing release of the brakes until the parts have returned to normal position by which time the train will have stopped. The piston b<11> does not return to normal until air is admitted by a pipe 57 from an independent brake-valve. The valve 19<a> is held opan by a latch 26<a> which is released by air supplied from the pipe 15<x> through a small hole 15<a>, thereby moving a piston 36<a> which withdraws the latch. Pressure in the meantime has built-up in a cylinder a<1> supplied by a pipe 37<x> and a piston b<1> therefore returns the valve 19<a> to normal. A port 22" then bleeds the pipe 15<x>. A piston g disconnects the core x from the linkwork f after operation of the valve 19<a> thereby closing the valve y. In a modification the core x operates the valve 19<a> directly. The piston b may be operated by air admitted by a mechanically operated trip in place of the solenoid 30. Under these conditions an auxiliary valve, operated when the handle of the engineer's valve is in the service position, admits air to the piston of a valve similar to the valve B, thereby closing the pipe 15x and cutting out the track control. Reference has been directed by the Comptroller to Specifications 5766/15, 136,570, 166,268, 190,425 and 190,447.