US1792427A - Railway-traffic-controlling apparatus - Google Patents

Description

Feb 16, 1931. A. T. JOHNSTON 1,792,427

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Sept. 30, 1929 YCJW ATTORNEY Patented Feb. 10, 1931 UNITED STATES PATENT OFFICE ALLAN T. JOHNSTON, OF MOUNT LEBANQN,.PENNSYLVANI.A, ASS IGN OR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION or PENNSYLVANIA RAILWAY-TRAFFIG-CONTROLLING APPARATUS Application filed September 30, 1929 Serial No. 396,042.

This invention relates to railway traflic controlling apparatus and particularly to the provision of means effecting the release of a floating track relay upon the arrival of a train at a definite point in a track section. Where a floating relay is connected to a track section the point in the section at which a train will release the relay often varies considerably due to varying ballast resistance and train shunts. I have devised means which effectively provide for release of the floating relay at a definite point, together with provisions afiording an indication of or check against any failure of said means. l

I shall describe one form of apparatus embodying my invention andshall then point out the novel features thereof in claims.

The accompanying drawing consists of a diagrammatic view illustrative of my invention.

Referring to the drawing, there is shown at 3 a section of railway track, the two rails comprised in said section being designated 4:, 5, respectively. To the rails at one end of said section the coil 6 of a track relay 6 is connected. The latter is shown as a standard form of two element relay, having a second winding 6", which is constantly connected with a source of alternating current not shown in the drawing. A track transformer 7 has its secondary 7 connected to the rails at the opposite end of said section for supplying current thereto. Connected across the track rails in parallel with said secondary 7 is a floating relay 8. In order .to provide for release of said floating relay upon the arrival of a train at a definitepolnt in the track section, or, in other words, to provide a defi' nite shunting point for said relay, I provide an insulated joint9 at the selected point in one of the rails 4 in saidtrack section, and

with rail 4; atone side of said joint Iconnect, as shown at 10,0ne terminal of an impedance 11. The other terminal of said'irnpedance 'is connected through wire '11 to a point 12 on the rail 15. The impedance .11

is shown .as forming the primary winding of a reactive transformer -l3,-comprising a core 1e. and a magnetic shunt 1%. Theses ing the voltage on the left hand side to such a value'as will shunt the floating relay. The armature 17 of the latter will therefore not be released by a train entering the track-section from the right until said train arrives at the point 12. When the train passes the joint 9, it will shunt winding 11, and the abrupt charge in the impedance of the track circuit willopenrelay 8. A definite point for the shunting or release of the floating relay 8 is thus provided.

t will be seen that the secondary winding 15 supplies to the rails at the right hand side of joint 9, and hence to the track relay coil 6, current induced in said secondary by the connected as to apply to the rails at the right hand side of the joint 9 instantaneous polarities the reverse of those applied by transformer 7 to the rails at the left of said joint. If the insulated joint 9 should break down, the polarity of the rails at the right of said joint will be reversed owing to the fact that they are now directly connected to the track transformer 7. Such reverse polarity appliedto the secondary iii-reduces the effective impedance of the transformer unit, and this in turn reduces the voltage between the rails at said unit. The result of the application of saidreverse polarity is that there is an insuflicient flow of current through the coil 6 of the track relay to hold up the-armature 18, and the relay is released. It will be apparent that a short circuit or an open cir' open circuit in either of the transformer windings, affords an indication that the impedance provided to establish a definite point for the release of floating relay 8 is ineffective. A check against failure of said impedance is thus provided. Should the common connection 11 of the transformer winding to the rails 5 be broken, the impedance across the joint 9 is increased, since the windings 14s and 15 are then placed in series with each other, and this will also result in release of relay 6.

hile I have shown the impedance element 11 as a winding of a reactive transformer it will be understood that a transformer other than one of the reactive type may be employed so long as the requisite amount of im pedance is provided. Also, it may be noted that while I have shown but one insulated joint 9, an additional insulated joint may be provided in the rails 5. Only one such joint is, however, required.

The terms and expressions which I have employed are used as terms of description and not of limitation, and I have no intention, in the use of such terms and expressions, of excluding any mechanical equivalents of the features shown and described or portions thereof, but recognize that various structural modifications are possible within the scope of the invention claimed.

What I claim is:

1. In combination, a section of railway track, a track relay connected to the rails adjacent one end of said section, a floating relay connected to the rails adjacent the other end of said section, a source of current connected with the rails in parallel with said floating relay, an insulated joint in one rai of said section, an impedance connected across the rails of said section adjacent said insulated joint, and means for causing the first mentioned relay to be released in response to breaking down of the insulated oint.

2. In combination, a section of railway track, a track relay connected to the rails adjacent one end of said section, a floating relay connected to the rails adjacent the other end of said section, a source of current connected with the rails in parallel with said floating relay, an insulated joint in one rail of said section, an impedance connected across the rails of said section adjacent said insulated joint, and means for causing the first mentioned relay to be released in the event that said impedance becomes ineffective.

3. In combination, a section of railway track, a source of current connected with the rails adjacent one end of said section, a fioating relay connected across the rails in parallel with said source, an impedance insuring release of said floating relay upon the arrival of a train at a definite point in said section, and indicating means responsive to failure of said impedance.

4. In combination, a section of railway track, a floating relay connected to the rails adjacent one end of said section, means insuring release of said floating relay upon the arrival of a train at a definite point in said section, and indicating means responsive to failure of the first mentioned means.

5. In combination, a section of railway track, a track relay connected to the ra': adjacent one end of said section, a floating relay connected to the rails adjacent the other end of said section, a source of current connected with the rails in parallel with said floating relay, an insulated joint in one rail of said section, and a transformer having one of its windings connected to said section at one side of said joint and the other of its windings connected to said section at the other side of said joint.

6. In combination, a section of railway track including an insulated joint, a track relay connected to the rails adjacent one end of said section, a source of current connected to the rails adjacent the other end of said section, a floating relay connected in parallel with said current supplying means and a transformer having a primary winding connected to the rails of said section at one side of said insulated joint and having a secondary winding connected to the rails at the other side of said joint in such man ner as to apply to said rails on such other side of said joint a polarity the reverse of that applied by said current supplying IIIQZLIIS.

7. In combination, a section of railway track, a track relay connected to the rails adjacent one end of said section, a floating relay connected to the rails adjacent the opposite end of said section, a source of current connected with the rails in parallel with said floating relay, an insulated joint in one rail of said section, and a reactive transformer connected to the rails adjacent said insu lated joint.

8. In .combination, a section of railway track, a track relay connected to the rails adjacent one end of said section, a floating relay connected to the rails adjacent the other end of said section, a source of current connected with the rails in parallel with said floating relay, an insulated joint in one rail of said section, and a reactive transformer one winding of which is connected to said section at one side of said joint and the other winding of which is connected to said section at the other side of said joint.

9. In combination, a section of railway track, a track relay connected to the rails adjacent one end of said section, a source of current connected to the rails adjacent the other end of said section, a floating relay connected with the rails in parallel with said source, and a reactive transformer one winding of which is connected to the rails of said section for receiving current from said source and the other winding of which is connected to the rails of said section for supplying current to said track relay.

10. In combination, a, section of railway track, a track relay connected to the rails adjacent one end of said section, a source of current connected to the rails adjacent the other end of said section, a floating relay connected with said rails in parallel with said source, an insulated joint in said section, and a reactive transformer one winding of which is connected to said section at one side of said insulated joint and the other winding of which is so connected to said section at the other side of said joint as to apply to the rails a polarity the reverse of that applied by said current supplying means.

11. In combination, a section of railway I track, a track relay connected to the rails adjacent one end of said section, a floating relay connected to the rails adjacent the other end of said section, a source of current connected with the rails in parallel with said floating relay, an impedance connected across the rails at an intermediate point in said section for insuring release of the floating relay upon the arrival of a train at a definite point in the section, and means for causing release of said track relay in the event of failure of said impedance.

12. In combination, a section of railway track, a track relay connected to the rails adjacent one end of said section, a floating relay connected to the rails adjacent the other end of said section, a source of current connected with the rails in parallel with said floating relay, an insulated joint in one rail of said section, and a transformer having each of its windings connected on opposite sides of said joint to one series of the rails of said section, said windings being connected through a common wire to the opposite series of rails.

In testimony whereof, I have signed my name to this specification this 27th day of September, 1929.

ALLAN T. JOHNSTON.

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