US562318A - Railway-signal - Google Patents

Description

(No Model.) I

F. MGBRIEN.

I RAILWAY SIGNAL. No. 562,318. Patented June 16, 1896.

WITNESSES: p INVENTOR A ATTORNEY ANDREW KGRANAM PNDTO-UMOMASHINGTOM. D c

Nrrnn STATES.

PATENT OFFICE.

FRANK MCBRIEN, OF NEWVARK, NEWV JERSEY.

RAILWAY-SIGNAL.

SPECIFICATION forming part of Letters Patent No. 562,318, dated June 16, 1896.

Application filed April 1, 1896. Serial No. 585,728. (No model) .To aZZ whom it may concern:

Be it known that I, FRANK MCBRIEN, a citizen of the United States, residing in Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Railway-Signals, of which the following is a specification.

This invention relates to electrically-controlled railway-signals, the object of the invention being to provide a system which will effectually guard the movements of trains and will permit the rails of the track to serve as the only conductors connecting the sev-- eral sections.

In carrying out my invention I divide the road into a number of sections and subsections or overlaps and place at or near the junctions of the sections the controllingelectromagnets which actuate the signals. The signals are preferably operated on a normal danger principle and are automatically thrown to safety when a train passes a signal if the track ahead be clear, but remain at danger if the track ahead be occupied. The signal is automatically restored to danger by the movement of the train. The signal device is positively drawn to a safety position by an electromagnetic device, such, for example, as an electric motor, the circuit of which is controlled by polar and neutral relays, the circuits of which include the trackrails. The relays are so connected that any interference with the track, as a broken joint or displaced rail or a short circuit of the two rails, will render it impossible for an approaching train to get a clear signal and a determined distance before and behind the signal will be effectually guarded.

The several features of novelty of the invention will be hereinafter more fully described and will be definitely indicated in the claims appended to the specification.

The accompanying drawing diagrammatically illustrates a system embodying my improvements.

A and B represent two sections of a railway-track, and a and b adjoining subsections or overlaps. The sections and overlaps are bonded or otherwise connected at the several rail-joints so as to form of each side of the track a continuous electric conductor for the length of the section or overlap.

The several sectionsand overlaps are insulated from one another by mounting the ends of the rails on an insulating-support and leaving an open space between adjoining rails. At the junction of a section and overlap are placed the controlling devices for the signaloperating circuit. These devices comprise two neutral relays 1 2, the former being normally open-circuited and the latter normally on closed circuit, and a polar relay 3.

The circuit of relay 1 leads through the front contact 4 of relay 2 and includes the trackrails on the side of the insulating-break of the track nearest an approaching train. The circuit includes a battery 5 of sufficient power to energize a relay, such as 10, bridging the rails at the rearward end of the section. The relay 2, as shown, is connected between the track-rails of the section and is wound to a higher resistance than relay 1. For example, the latter may have a resistance of one-half ohm and the former eight ohms. Relay 2 may, if desired, be placed in series with the polar relay, instead of in parallel, as shown.

The armatures of relays 1 and 2 control the circuit of battery 6, the armature 7 of polar relay 3 being also included in the circuit.

This circuit contains an electromagnetic device, as a motor 8, which when actuated draws down the semaphore 9, or other visualsignal, to a position of safety. The controlling-circuit for the signal is thus dependent upon the condition of three circuit-breakers, all of which must be closed at the same time before a clear signal can be given. If the integrity of the rail-circuit, in front of or behind a signal, is impaired in any way, as by a broken bond or fish plate, a displaced rail, a short circuit of the track-rails, or otherwise in any way which would rupture its continuity or unbalance its electrical condition, it is evident that relay 2 will drop its armature, thus opening the signal'operating circuit, as well as incapacitating relay 1, keeping the danger-signal continuously set until the circuit is repaired. At the end of each overlap is placed an organization for controlling the movements of the polar relay, for maintaining the rails normally charged with current high-resistance relay 10, bridging the rails of section B, and a low-resistance relay 11 in circuit with a circuit-closer 12, actuated by relay 10 and the two rails of overlap a. The armature 13 of relay 11 controls a circuitcloser for a normallyopen shunt-circuit across the rails of section B, which prevents polar relay 3 shifting its contact to an active position when sections a, B, or b is occupied. The armature 12 of relay 10 plays between two contacts connected with opposite poles of a battery 14, the middle point of which connects with one rail of section a through relay 11, the pivot of armature 12 being connected with the other rail. The battery is thus split, being always connected with the rails but capable of changing its poles with relation thereto. Asimilar arrangement of circuits and apparatus is provided for the other sections and overlaps of the system, as seen by the similarly-lettered parts in sections B and I).

Let us suppose first that the track in section B and overlaps a and b is clear, and that a train is in A. Relay 2 will be energized by current from battery 14. The open point 1 of the controlling-circuit for relay 1 is therefore closed, and the car-axles in section A complete it and close two points of the signaloperating circuit, one of these points being under control of the armature of relay 1 and the other under control of the armature of auxiliary relay 2. Relay 10 would be on its front stop, being energized by current from battery 5 in section B, and polar relay 3 would close the third point of the signal-operating circuit at 7. To renderthe action of the polar relay reliable, it may be given a bias toward its open stop by a light spring. Battery 6 would thus drive motor 8 and draw down semaphore 9, indicating a clear track. If, however, a train or a single pair of wheels stood in section a, B, or b, the motor-circuit would be open; if the train were in B, relay 10 would drop its armature and reverse battery 1 1, thus throwing relay 3 to its open stop; if the train were in b, relay 2 would be short-circuited, opening rail-circuit of B at the battery 5 and deenergizing relay 10, thus reversing polar relay 3; if the train were in a, relay 2 would be shorteircuited, thus opening the signal-operating circuit and preventing a clear signal being given. Let us suppose now that the train enters overlap a and that the track of section B and its overlap are clear of trains. The conditions will then be as shown in the drawing. Relays 2 and 3 are short-circuited by the wheels; relay 11 is energized by battery 14, the circuit being completed by rails of section a and the car-wheels; the short circuit at 13 for rails of section B is therefore completed and relay 1 is energized; armature of relay 2 is held up and the operating-circuit of semaphore 9 is closed,thus throwing it to safety. Relay2, however, is short-circuited by the wheels in section a, and battery 6 is opened, thus permitting a weight or spring to restore semaphore 9 to danger for a following train. It will be seen that low-resistance relay 1 is in series relation to high-resistance relay 10. I11 the normal condition of affairs the current is amply sufficient to lift the armature of the high-resistance relay but too weak to lift the armature of the low-resistance relay, which, however, acts when the strength of current is increased by a low resistance across the rails made by a pair of car-wheels.

It will thus be seen that but little battery power is required, since the main batteries employed to operate the signals are in service only for short periods during the transit of a train, the normal functions of the system being subserved by the small batteries 5 5 and 1 1- 14, the only work of which is to energize the high-resistance and polar relays. The expense of maintenance is therefore low, and the expense of equipment is obviously low because all wiring along the track is dispensed with.

The system has been described as a normal danger system. I desire to have it understood, however, that certain features maybe applied also to a normal safety system; but a slight change in the organization is needed to convert the organization shown into a normal safety system. This may be accomplished by dispensing with the low-resistance relays 1 1 leaving only the high-resistance relay and polar at the signal-station. With such an organization, the polar relay nor mally holds its armature on the front stop and the neutral relay holds up its armature, thus closing the signal-operating circuit and positively holding the signal at safety when the track is clear. Dotted lines have been placed on the drawing to indicate this organization. Let us suppose a train enters section a. Relay 2 is short-circuited and opens the motor-circuit, thus putting the sig nal to danger; but if a train is standing or moving in sections B or b or a the signal would have been thrown to danger before the following train reached the signal; if in a, relay 2 will drop its armature and open the motor-circuit, thereby setting a danger-signal; if in B, relay 10 will drop its armature and reverse polar relay 3, thus setting a danger-signal; if in b, relay 2 is deenergized, also relay 10, and the polar armature is thus shifted to the left, thus setting a danger-signal. The signal having been put to danger by a passing train will be automatically restored to safety when the last pair of wheels pass out of overlap 1).

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. A railway signal system comprising a plurality of track-sections insulated from one another, a plurality of signal devices, a motor for operating each signal device, a neutral and a polar relay at each signal-station controlled by a track-circuit common to both, and an operating-circuit for the motor includ-

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