US1502934A - Means for testing track circuits - Google Patents

Description

July 29 1924-. 1,502,934

A. B. BARNETT MEANS FOR TESTING TRACK CIRCUITS Filed Dec. 10. 1923 3 Sheets-Sheet 1 jzyl.

INVENTOR ufll'iliwrnaifi,

KLJ ATTORNEY July 29 1924. 1,502,934

A. B. BARNETT MEANS FOR TESTING TRACK CIRCUITS Filed Dec. 10 v192s 3 Sheets-Sheet '2v INVENTOR' g vflfl fiarneiij fhzw ATTORNEY July 29, 1924. 1,502,934

A. B BARNETT MEANS FOR TESTING TRACK CIRCUITS Filed Dec. 10 1923 5 Sheets-Sheet llllllllHl INVENTOR J. B. Earwaii,

fi ATTORNEY Patented July 29, 1924.

fiTED STATES somer ABRAHAM B. BARNETT, OF ROANOKE, VIRGINIA.

MEANS FOR TESTING TRACK CIRCUITS.

Application filed December 10, 1923., Serial no. 19,771.

To all whom it may concern:

Be it known that I, ABRAHAM B. BARNETr, a citizen of the United States of America, residing at Roanoke, in the county of Roanoke and State of Virginia, have invented certain new and useful Improvements in Means for Testing Track Circuits, of which the following is a specification.

This invention relates to devices for testing and locating faults in electric circuits, and more particularly in circuits composed principally of the rails of a railroad track.

In railway block signal systems, such as are in common use at the present time, the track rails are divided by means of insulated joints into sections or blocks of a mile or more in length, and each rail'constituting such block is rendered electrically continuous throughout its length, b means of bonds bridging each rail joint. lhese bonds are in the nature of short copper conductors, riveted or otherwise secured to the rail ends.

A source of current is connected across the rails at one end of the block, and a track relay, controlling a wayside signal, is connected across the rails at the other end of the block, so .that' a completely closed circuit, including both rails of the block, is formed, in which circuit ,current continually flows from the source of current through one track rail, through. the track relay and back through the other track rail to the source of current. The source of current may be either a track battery, where direct current is employed, or a low voltage transformer, in cases where alternating-current is used.

In practice, it often happensthat the above described track circuit becomes interrupted by reason of a broken rail,or a corroded, loose orbroken bond, and when this occurs, the wayside signal remains in the stop or danger position, thus frequently delaying traffic and causing great inconvenience. Heretofore, in order to locate .the break or defect in the track circuit, it has been necessary for an inspector to traverse the block on foot, andexamine and test each joint and bond to find out just where the defeet is. time consuming operation.

This, of course, is a tedious and The primary object of the present invention is to provide testing apparatus in the nature of a small car, so constructed and arranged that it can be simply run over the block of track which is out of order, and will indicate to the operator the exact location of the defect or fault, by means of a signal brought into action immediately that the car passes over the point which is causing the trouble. A further object is to provide means for automatically bringing the car to a stop when it encounters a broken or loose connection in either rail, such as would interrupt the continuity of the track circuit, thus serving as an additional and positive indication of the location of the trouble.

In order that the invention may be readily understood, reference is had to the accompanying drawings, forming part of this specification, and in which Figure 1 is a side view of a small motor driven car, equipped with testing instruments, in accordance with my invention;

Figure 2 is an end elevation thereof;

Figure 3 is a diagrammatic plan view of a fragment of track, with the wheels of the car resting thereon, and showing the instruments and circuits which I preferably em- P y;

Figures 4 and 5 are a cross-section and side elevation, respectively, of one of the wheels with which the car is equipped;

Figure 6-is a fragmentary'end elevation of one of such Wheels, showing the manner in which it may be insulated from the other wheels and the rest of the car frame; and

Figure 7 is a diagrammatic view showing, on an enlarged scale, my improved means for stopping the car and giving a visual signal when a defect in the track circuit is encountered.

Referring to the drawings in detail, I haveillustrated, in Figures 1 and 2, a car of the type commonly employed on railroads by inspectors, and comprising a frame in which are journaled two main-wheels 23, and two smaller auxiliary wheels 3. One of the 'main wheels is driven by means of an internal combustion engine 4. 5' designates the seats for the operator and inspector, and 6 indicates the control level, by means of which the car is operated.

The wheels 3, of cars of the typeillustrated, are usually made as shown in Figures 4 and 5, comprising a metal rim, 'a metal hub 3 and a web 3 formed of a wooden disc. In order to adapt these wheels for use in connection with my present invention, I attach a' conducting strip 15, to the wheel, such strip extending from the rim to the hub, and forming an electrical connection between them.

In order to insulate the wheels 3 from the wheels 23, and the main frame of the car, a construction such as shown in Figure 6 may be employed. Referring to this figure, 16 designates the spindles on which the wheels 3 are journaled, such spindles being secured, as indicated at 16 to the ends of guide arms 2, formed of wood or other material of a sufficiently insulating nature to prevent the passage of such low voltage current as is encountered on the track circuit. The usual braces 2 may also be secured to the wooden arms 2, as shown in Figure 6.

In Figure 3, I have shown the wheels'3 as mounted upon the spindles 16, and have conventionally illustrated, in the usual manner, the fact that these spindles are insulated from the rest of the car. The wheels 23 are mounted upon separate spindles 26, journaled in suitable boxes carried by the frame of the car, in the usual manner.

7 designates a battery mounted on the car, such as is ordinarily used for ignition in connection with the gasoline motor, and to the rear of this battery, I place a panel or instrument board 8, supported on brackets 14, as clearl shown in Figure 1. On this instrument oard are; preferably mounted two low voltage lamps 9 and 10, two switches 12, two binding posts 13, and an indicating lnstrument 11, in the nature of an ammeter. The lamps and indicating instrument are. connected in multiple between two conductors 16 and 16. The conductor 16 connects with a. wire 16, which is secured to the spindles 16 of the wheels 3, while the conductor 16 is connected with the other wheels 23, through the frame of the car.

While I have shown two lamps 9 and 10, it will be understood that only one of these lamps is used at any one time. The two lamps are provided because of the fact that on some sections, a railroad may use direct current of one voltage, and on other sections. alternating current of another voltage, in the track circuit. It will be understood that by opening or closing the respective switches 12, either one or the other of the lamps 9 and 10 may be included in the circuit, in accordance with the character of current in the particular block being tested.

Assuming the car thus equipped to be traversing a block, traveling in a direction away from the end to which the tracltbattery is connected, it will be obvious that current from such battery or other source will flow along one rail 1 up through the wheels 3, conductors 16 and 16, to and through one of the lamps 9 or 10, and the indicating instrument 11, thence through the conductor 16, wheels 23, and through the other rail 1 baclg to battery. This forms a complete circuit, including the track rails, and one of the lamps 9 or 10 will thus be caused to glow, andth'e indicating instrument 11 will show a, certain strength of current passing through the circuit. As soon, however ,i as the car passes over a broken or loose connection, or other defect, in either track rail, the above described series circuit is immediately interrupted, and the signal lamp goes out and the pointer of the indicating instrument 11 swings back to zero. The operator will thus be immediately advised of the fact that he has encountered the de fect or trouble for which he was testing, and-by at once stopping the car, and examining the rails for a few feet back, he will beable to readily locate the fault.

It sometimes happens that the defect is inthe nature of a loose or corroded joint, which will permit suflicient current to pass to cause the lamp 9 01 10 to, continue-to glow, and in such a case, the presence of the defect will be shown by the indicating instrument, the pointer of which will swing back toward zero a distance proportional to the resistance of the loose connection encountered.

In order to make even more positive the operation of my improved testing device, I may and preferably do also equip the car with the apparatus shown in detail in Figure 7, and also conventionally illustrated in Figure 3. Referring to Figure 7, 8 des ignates a second panel .or instrument board, on which is mounted an electromagnet l7. and a special signal lamp 27-. The windings of the electromagnet 17 are connected through a circuit 16 with the conductors 16 and 16, extending to the wheels at each side of the car respectively. Arranged to cooperate with the electromagnet 17 is an armature 17, carried at the end of a lever 18, pivoted at 18 to the panel board, and provided with a hook or detent 18 .When the lever 18 is in the horizontal position shown in full lines in Figure 7, this detent is adapted to engage under a shoulder'l9 formed on a weight 19, arranged to slide freely on a vertical rod.20, held by brackets 21, secured to the anel board. This weight is preferably ma e of metal, and each end thereof serves as a switch. Adjacent one end of the guide rod 20 is a pair of spaced insulated contacts 22, and adjacent the other end of the rod is a pair of similar contacts bridges the contacts 22.

I 22. When the weight 19 is in its elevated position, as'shown in full lines in Figure .7,- it engages and bridges the contacts 22, and when it is in its lowermost position, as indicated in dotted lines, it. engages and ductors 22", which constitute the ignition" circuit extending from the battery 7 to the internal combustion engine, the cylinder of which is indicated at 4", and is shown as having a spark plug 4, mountedtherein Aj timer or similar interrupting device 24 is, of course, interposed in the ignition. cincuit. When the weight 19 is in its elevated position, it bridges the contacts 22 'and thus maintains the ignition circuit in an operative condition, but when this weight moves downward, it opens theignition circuit at the contacts 22.

From the above, it will be obvious that, assuming the car to be traveling in a direction away from the track battery, as above described, current from such track battery will -fiow throu h the rails and 'wheels through the win ings of. the electromagnet' 17', by way of the conductor 16", thus maintainmg said ele'ctromagnet energized, so long as the track -circuit'is not interrupted. The

armature 17 and lever 18 are thus held in the position shown in full lines, and the detent 18 sustains the weight 19, in its elevated 'osition, maintaining the ignition circuit c osed at the contacts 22. When the car encounters a loose connection or other defect in the track circuit, however, the electromagnet 17 immediately becomes de- ,energized,- and releases its armature, the

lever 18 thereupon swinging up to dotted line position, and permitting the weight 19 to fall. The falling of the weight performs the-two-fold function of opening the ignition circuit at the contacts 22*,thus immediately stopping the motor, and of closing the lamp circuit at the contacts 22, thus causing the signal lamp 27 to flash up.

Thus, the car is automatically brought to a stop at approximately the point where the fault or trouble in the track circuit is en-' countered," and the defectmay then be accurately located, without .further' trouble.

It will'thus-be seen that I have provided improved means whereby a fault or defect in the track circuit of any given block may be definitely located, within a few minutes time, and thus extended delays to traflic' avoided, and it is thought that the many advantages. of my invention will be fully appreciated without further discussion.

i What Iclaim is 1. 'Apparatusfor testing the continuity of a track circuit having a source of current 5 connected between the rails thereof, comprising a car adapted to run upon the rails andhaving the wheels on one side insulated from those on the 'other side, an electromagnet on said car having one end of its winding connectedwith the wheels at one side of the car and the other end of its winding connected with the wheels at the other side of the car, whereby said winding is included in a circuit with said source of current, through the rails, a lampand a battery carried by said car, an electric circuit connecting said battery and lamp and including a pair of contacts constituting a switch,

imeans controlled by said electromagnet,

when energized, for maintaining said switch open, and means, operating automatically upon the de-energization of said electrobetween said circuit. I

2. Apparatus for testing the. continuity of a track circuit having a source of current connected between the rails thereof, comcontacts and closing said lamp prising a car adapted to run upon the rails carried by said car, a'circu'it for supplying ignition current from said battery to sai a switch in said circuit, 'means conmagnet, for forming an electrical connection gine. tro ed by said electromagnet, when eneF- gized, for maintaining said switch closed, and means operating automatically, upon de-energization of said electromagnet, for

opening said switch, and thus stopping the car. I

3. Apparatus fortesting the continuity of a track circuit having a source of current connected between the rails. thereof, com-- prising a car adapted to run upon .the rails and having the wheels on one side insulated from those on the other side, an internal combustion engine for driving said car, an electromaglnet on said car having one end mg connected with the'wheels at 1 of .its win 7 one side of the car, and the other end of its winding'connected with the wheels at the other side of the car, whereby said winding is included .in a .series circuit with said source of current through the rails, a batterycarried by said car, a circuit for supplying ignition current. from said battery .to said engine .a switch in'said circuit a lamp also on sai car, a circuit forsupplying current J and said lamp circuit switch open, and

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from said battery to said lamp, said circuit including a switch, means controlled by said electromagnet, when energized, for -maintaining said ignition circuit switch closed simultaneously closing said lamp circuit switch and opening said ignition circuit switch, whereby a signal is given and the car 19 stopped when any break-in the continuity of the track circuit is encountered. I means operating automatically, upon de- In testimony whereof I afix my signature. energization of said electroniagnet for ABRAHAM B. BARNETT.

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