US1792835A - Apparatus for the control of highway-crossing signals - Google Patents

Description

Feb. 17,' 1931. I L. o. GRONDAHL 1,792,335

APPARATUS FOR THE CONTROL OF HIGHWAY CROSSING SIGNALS Filed March 18, 1930 INVENTOR; L ,O. Gronda Patented Feb. 17, 1931 x unrrao WSTATES PATENT OFFICE LABS O. GBONDAHL, OI PITTSBURGH, PENNSYLVANIA, ASS I IGNOB TO THE UNION SWITCH a SIGNAL COMPANY, OF BWISSVALE, PENNSYLVANIA, A CORPORATION 01' PENNSYLVANIA AIPARATUS FOR THE CONTROL OF HLGHWAYJJBOSSING SIGNALS Application filed March 1a, 1930. Serial 1%. 436,841.

My invention relates to apparatus for the 5 trolling signals 0 this character without the necessity for continuous track circuits. In accordance with one form of my invention, the necessity for track circuits is eliminated entirely. Iwill describe two forms of apparatus embodying my invention, and will t on polnt out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view showingone form of apparatus embodying my invention, in which form the necessity for track circuits is avoided. Fig. 2 is a view showing a modification of the apparatus shown in Fig. 1 and also embodying my invention, but requiring short isolated track sections for the control of the highway crossing signal.

Similar reference characters refer to similar parts in each of the views.

Referring first to Fig. 1, the reference characters 1 and 1 designate the track rails of a railway track A, which track is intersected by a highway H. Located at the intersection of the railway track and the highway is a highway crossing signal S, which as here shown, is in the form of an electric bell.

Located to the left of the highway H is a light sensitive cell G which normally re ceives light from a lamp L these elements being so disposed that the supply of light to the cell C is discontinued when a train or car passes between the elements. Preferably the lamp and the cell are disposed on oppo site sides of the track at about the level of the axles of a car, and are diagonally disposed with respect to the track, so that the supply of light to the cell C is continuously cut off during the passage of a car. The cell C comprises an enclosing tube which is open at the end toward the track, in order to prevent the light sensitive element of this cell from being influenced by light otherthan that which is received from the lamp L Similarly, the lamp L comprises an enclosing tube which is open at the end toward the track and the inner end of which constitutes a reflector.

Other cells C C and C are dis osed along the track between the cell C and t e highway "H, and are arranged to be normally supplied energized relays E and F, the former of which preferably comprises two windings 18 and 19. V V1nd 1ng18 of relay E is provided with a stick circuit which passes from terminal B of a suitable source of current, through cell C front contact 8 of relay E, and winding 18 of this relay to terminal 0 of the same source of current. This winding is also provided w th a pick-up circuit which passes from terminal B, through the cell C front contact 12 of relay F, and winding 18 to terminal 0. Wlnding 19 of relay E is provided with a holdlng circuit which passes from terminal B, through front contact 9 of relay E, windmg 19 of this relay, and back contact 13 of relay F to terminal 0.

Relay F is provided with a stick circuit which passes from terminal B, through cell C front contact 11 of relay F, and the windng of this relay to terminal 0. This circuit 15 provided with a branch around the cell C, which includes cell G so that relay F will become deenergized when and only when both of the cells C and C are dark. These cells are placed close enough to ether to insure that they will both be dar ened at the same time by a passing train. The reason for providing two cells for the control of relay F, is to prevent this relay from being deenergized by a person walking along the track. Momentary darkening of the other cells will not disarrange the apparatus.

A third relay G is provided with a circuit which includes cell C, whereby this relay is normally energized but becomes deenergized while a train is passing the highway H. As-

sociatd with relay G is a normally deenergized slow-releasin relay M provided with a circuit which includes a back contact 1501: relay G. It follows that when a train passes highway H, relay M will become energized while relay G is deenergized, whereupon after relay G again'becomes energized, the front contacts of rela M will remain closed for a brief interval time.

Relay F is provided with a pick-up circuit which passes from terminal B, through the cells C and C in multiple, front contact 16 of relay G, front contact 17 of relay M, and the winding-of relay F to terminal O.

Another relay D is provided with a circuit which includes cell G and another slow-releasing relay K is provided with a circuit which includes back contact 5 of relay D. Relay F is provided with a second pick-up circuit which includes front contact 6 of relay D, and front contact 7 of relay K in series.

The signal S is provided with a circuit which passes from terminal B, through back contact 10 of relay E, back contact 14 of relay F, and the signal S to terminal 0. It follows that this signal will operate when and only when both relays E and F'are deenergized. 77

The operation of the apparatus shown in Fig. 1,is as followsz y Y Normally all of the relays except K and M are energized, so that the signal S is inactive. While a train moving toward the right is passing the cell C it will deenergize relay D, and this will energize relay K, but the operation of these relays has no effect on the rest of the apparatus. -When the train passes cell C it will reduce the current in both the stick and the pick-up circuits for relay E to such'value that this relay will release. Then before the train loses its influence on cell C it will obscure cells C and C thereby reducing the current in the stick circuit-for relay F to such an amount that this relay, likewise, will release. Relay. F will then stay open, because both of its pickup circuits are open, and relay E will stay open because its pick-up circuit is open at contact 12 of relay F. Relays'E and F both being open, the signal S will operate to indicate that a train is approaching the highway H. When the train passes the highway, it will d'eenergize relay G, and this will energize relay M; then during the brief interval of time in which contacts 16 and 17 of these relays are both closed, one of the pick-up circuits for relay F will be closed, so that this relay will again become'energized. The closing of contact 12 of relay F will close the pick-up circuit for relay E, so that the latter relay will, likewise, become energized. The operation of the signal S will therefore be discontinued, and the parts of the apparatus will be restored to the conditions in which they are shown'in the drawing.

{When a train moves in the other direction, that is, toward the left, it will deenergize relay G when it passes the highway H, and this will energize relay M, but this 0 eration of relays G and M will have no e ect on the other parts of the ap aratus. When the train obscures both cells a and C relay F will release, thereby closing the holding circuit for winding 19 of relay E at back contact 13 of relay F. It follows that when the train obscures cell CF, relay E will remain energized, because this holding circuit remains closed. Consequently, signal S will not be set into operation because its circuit will remain open at back contact 10 of relayE. When the train passes cell C the second pick-up circuit for relay F will become closed, so that this relay will become energized, and all parts ,of' the apparatus will be restored to the conditions in which they are shown in the drawing.

Referring now to- Fig. 2, the apparatus shown in this view is the same as that shown in Fig. 1, except that short insulated track sections are substituted for the light responsive cells for the control of relays D, E, F and G. Three short sections P P and P are located to the left of the highway H, and a fourth section P is located at the highway, these sections being formed by insulated joints 2 in one of the rails 1. Each section is provided with a source of current connected across the rails 1 and 1, this source being represented by the terminals B and O.

is connected across the rails at section I,

through front contact 8 of this relay and contact 12 of relay F in multiple, so that relay E is provided as in Fig. 1 with a stick circuit and a pick-up circuit. The holding circuit for winding 19 of relay E is the same as in Fig. 1. Relay F is connected across the rails at section P through its own front contact 11, so that this relay is provided with a stick'circuit as in Fig. 1. The two pick-up circuits for relay F are. the same as in Fig. 1, and the circuit for the control of signal S,

is, likewise the same as in Fig. 1. The operaducing the current in the stick and 1. In combination, a railway track intersected b a hi hway, two normally energized rela' s and F, a stick circuit for rclay inclu ing its own front contact, a pick-up circuit for relay E including a front contact of relay F, a holding circuit for relay E including its own front contact and a back contact of relay F, a stick circuit for relay F including its own front contact, a normall energized relay G, a slow-releasing relay controlled by a back contact of relay G, a pick-u p circuit for relay F including front contacts of relays G and M in series, means controlled by a train approaching said highway folr; re-

10 -u circuits for relay E to open this relEiy an for subsequently reducin the current in the stick circuit for relay E to open the same before relay E can close, means controlled by such train when it reaches the highway for causing relay G to release, and a highway crossing signal controlled by said relays E and F.

2. In combination, a railway track intersected b a highway, two normally energized relays lil and F, a stick circuit for relay E including its own front contact, a pick-up circuit for relay E including a front contact of relay F, a holding circuit for relay E includin its own front contact and a back contact of relay F, a stick circuit for relay F includin its own front contact, a normally energized relay G, a slow-releasing relay M controlled by a back contact of relay G, a pick-up circuit for relay F including front contacts of relays G and M in series, means controlled by a train approaching said highway; for reducing the current in the stick and pic -up circuits for relay E to open this relay and for subsequently reducing the current in the stick circuit for relay F to open the same before relay E can close, means controlled by such train when it reaches the highway for causing relay G to release, a normally energized relay D, a slow-releasing relay K controlled by a back contact of relay D, a second pick-up circuit for relay F including front contacts of relays D and K in series,

means controlled by retrain moving away from'said highway for causing relay D to release after the train has passed the locations wherein relays E and F are influenced, and a highway crossing signal controlled by said relays E and F.

3. In combination, a'railway track intersected by a highway, three sources of light disposed along the railway, three light responsive cells C C and C normally receiving light from said three sources respectively but arranged to be successively obscured by a train approaching said highway, two relays E and F, a stick circuit for relay E including a front contact thereof and cell G a pick-up circuit for relay E including cell C and a front contact of relay F, a holding circuit for relay E including a front contact thereof and a back contact of relay F, a stick circuit for relay F including a front contact thereof and cells C and Cfi in multiple, a fourth source of light and a fourth light responsive ,cell C normally receiving light t ierefrom but obscured when a train is adj acent said highway, a relay G provided with a circuit including cell C, a slow-releasing relay M controlled by a back contact of relay G, a pick-up circuit for relay F including, front contacts of relays G and M in series, and a hi hway crossing signal controlled by relays li and F. I

4. In combination, a railway track intersected by 'ahighway, three sources of light disposed along the railway, three light responsive cells C, C and C normally receiving light from said three sources respectively but arranged to be successively obsoured by a train approaching said highway, two relays E and F, a stick circuit for relay E including a front contact thereof and cell G a pick-upcircuit for relay E including cell C and a front contact of relay F, a holding circuit for relay E including a front contact thereof and a back contact of relay F, a stick circuit for relay F includin a front contact thereof and cells C and in multiple, a fourth source of light and a fourth light responsive cell C normally receiving light therefrom but obscured when a train is adjacent said highway, a relay G provided with a circuit including cell C, a. slow-releasing relay M controlled by a back contact of relay G, a pick-up circuit for relay F including front contacts of relays G and M in series, a fifth source of light and a fifth light responsive cell C arranged to be obscured by ,a train moving away from the highway after it has influenced cell G a relay D provided with a circuit including cell C, a slow-releasing relay K controlled by a back contact of relay D, a second pick-up circuit for relay F including front contacts of relays D and K in series, and a highway crossing signal controlled by relays E and F.

5. In combination, a railway track intersected by a highway, said track being provided with three short insulated sections P P and P arranged to be bridged successively in the order named by a train approaching the highway, and with a fourth section P located adjacent the highway, a source of current connected across the rails of each section, two relays D and G connected across the rails of sections P and P respectively, a relay F having a winding connected across the rails of section P through a front contact of the relay itself, a relay E having a winding connected across the rails of section P through apath which includes a front contact of the relay itself and a front contact of relay 'F in multiple, a holding circuit for relay E including a front contact thereof, and a back contact of relay F, two slow-releasing relays K and M controlled by back contacts of relays D and G, respectively, two shunts for thecircuit of relay F around the front contact thereof, one of which shunts includes front contacts of rela s G and M in series and the other of which mcludes front contacts of relays D and K in series, and a highway crossing signal controlled by said relays E and F.

6. In combination, a railway track intersected by a hi hway, two normally energized relays E and i means controlled by a train approaching the highway for first deenergizing relay E and for subsequently deenergizing relay F before its influence over relay E ceases, means for preventing relay E from becoming reenergized until relay F again becomes energize means controlled by such train when it reaches the highway for reenergizing relay F, means responsive to the prior deenergization of relay F when a train moves in the other direction for preventing relay E from being deenergized by such train, means controlled by a train moving last-mentioned direction for reenerglzing relay F after it has passed the points at which said relays are influenced, andva highway crossing signal set into operation when and only when relays E and F are both, deenergized.

In testimony whereof I afiix my signature.

LARS O. GRONDAHL.

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