US1584991A - Railway signaling - Google Patents

Description

May 18 1926. 1,584,991 F. H. NICHOLSON RAILWAY SIGNALING Original Filed April 21, 1921 iNVENTOR I H-w. ATTORNEY Patented May 18, 1926.

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FRANK H. NICHOLFSON, 0F PHILADELPHIA, PENNSYLVANIA, ASSIG'NOR TO THE UNION S'WITGH s SIGNAL COMPANY, OF SWIISSVALE, IENESYLVANIA, A CORPORATION OF PENNSYLVANIA.

RAILVIAY SIGNALZNG.

Original application filed April 21, 1921.

Renewed January 22, 1923, Serial No. 463,234. Divided and this a-Pplieation filed November 17,1924. Serial No. 750,293.

My invention relates to railway signaling, and particularly to signaling of the type wherein roadside signals are controlled in accordance with the presence and absence of trains through the medium of track circuits.

I will describe one form of signaling apparatus embodying my invention, and will then point out the novel features thereof in claims. 1

The present case is a division of my copending application, Serial No. 463,234, filed Jan. 22, 1923, as a renewal of my original application, filed April 21, 1921, for railway signaling.

The accompanying drawing is a diagrammatic view showing one form of signaling apparatus embodying my invention.

Referring to this drawing, the reference characters E and E designate the track rails of a stretch of railway track over which trafiic normally moves in the direction indicated by the arrow. These track rails are divided, by means of insulated joints 2, into a plurality of successive track sections A B, B-C, etc., and each section is provided with a roadside signal which is designated by the reference character S with an exponent corresponding to the location. As shown in the drawing, each of these signals is of the semaphore type, adapted to indicate St-op, Caution or Proceed according as the semaphore blade is in the horizontal, inclined or Vertical position.

Each track section provided with a track circuit comprising a transformer designated by the reference character T with an exponent corresponding to the location, the secondary of which transformer is connected across the rails adjacent the exit end of the section. The primary of each transformer T is supplied with alternating current from some suitable source such as an alternator l, overa transmission line As her .hown the supply of such current toeach transformer is control ed by a pole changer operated by the adjacent signal and designated by the reference character P with a suitable exponent. Each pole changer is operated during the movement of the signal between stop and caution positions, and so the section in the rear of an occupied section is supplied with alternating current of one relative polarity, which I will term the reverse polarity, whereas all other sections are supplied with current of the opposite relative polarity, which I will term normal polarity.

Each track circuit also comprises a transformer designated H with a suitable exponent, the primary of which is connected across the track rails at the entrance end of the section, and the secondary of which controls the corresponding signal S through-the medium of apparatus which I will now describe.

Each signal S is controlled directly by a relay designated by the reference character F with a suitable exponent. Each of these relays is of the usual direct currenttype, having a neutral armature responsive to the presence and absence of current, and a polarised armature responsive to the direction of flow of current through the relay winding. The winding for this relay is in two sections, designated 27 and 27, which sections are connected at the middle so that the relay is what may be termed a dill'erential polarized relay. That is, if current flows into the relay through wire 28 and passes through the upper section 27, the neutral aunature will be closed and the polarized armature will be swung to one extreme position. if current enters the relay through wire 28, but flows through the lower section 52?, the neutral armature will still be closed but the polarized armature will he swung to its opposite erztreme position.

The supply of energy to each relay 1 is controlled by two electron tubes D and 1) associated therewith and each comprising, as usual, a filament 5, a. grid 6, and a plate Each section is further provided with a transformer designated by the reference character 5 with an appropriate exponent. The primary 15 of each such transformer d is constantly supplied with alternating cur rentfrom transmission line 3.

Referring particularly to location it, the signal S is provided with a caution indication circuit which passes from a secondary 29 of transformer J through wire 30, nontral contact 31 of relay F wire 32, operating mechanism ofsignal S, and wire 33 to secondary 29. The signal is also provided with a proceed indication circuit which passes from secondary 29, through wire .30,

contact 31 of relay 1*, wire 3i, polarized contact of relay F, wire 36, operating mechanism of signal S, and wire 33 to secondary 29. The caution indication circui of course, closed when eith r winding of relay F" energized, but the proceed indication circuit is closed only when contact 35 is swung to the left, and this occurs only when the upper winding 27 is energized. The controlling circuits for each of the remaining signals are the same as those for signal S Still referring to the apparatus associated with signal S, the relay F is supplied with current from a secondary 16 or the transformer J and this supply is governed by the two electron tubes'D and D associated therewith, which in turn are controlled by the transformer H. The electron tube filaments 5 are heated by a secondary S on transformer J these filaments as here shown being connected in series. Tube D is provided with a grid circuit which passes from the right hand terminal of secondary 23 of transformer H through wire 25, grid (3 and filament 5 of tube D, and wires 38 and 2-1 to the middle point of secondary 23. Similarly, the grid 6 of tube D is connected with the left hand terminal of secondary 28 through a wire 26, while the filament 5 of this same tube is connected with the middle point of secondary 23 by wires 41. 2e and 2f. It will be seen from the foregoing. that at any given instant the polarities of the grids 6 of the two tubes D and D are opposite; that is, when the grid of tube D is positive with respect to its associated filament, the grid of tube D 15 negative with respect to its associated filament.

The circuit for the secondary 16 of trans former J comprises two branches, one of which includes section 2? of the winding of relay F and electron tube D, whereas the other branch includes section 27 of the relay winding and electron tube D First considering tube D, the complete plate circuit for this tube is from the left hand terminal of secondary 16, through wire 28, section 27 of the winding of relay F wire 37, tube D", and wires 38, 9A and 39 to right hand terminal of secondary 16. As for tube D the complete plate circuit is from secondary 16, through wire 28, section 27 of the winding of relay F wire 40, tube D and wires all and 39 to secondary 16.

The primary 15 of transformer J is connected with the transmission line 3, and the parts of the apparatus are so adjusted that the plate circuit voltages in tubes D and D are either substantially in phase with, or displaced substantially 180 from the grid voltages applied to these tubes by transformer H It follows that when pole changer P is in one position, the grid 6 of tube D will be positive with respect to the filament at the same instant that the plate 7 of this tube is also positive with respect to the filament. hen this is the case, current will flow freely from seeonary 16 through tube D and winding sec tion 2? of relay F, but substantially no current will flow through tube 1) and section 27, because the grid of this tube is negative with'respect to the filament at the instant that the plate 7 is positive with respect to the filament. The arrangement is such that tube D is thus conductive when signal S indicates caution or proceed, that is. when track section BC is unoccupied. When pole changer P is reversed, however, it will be obvious that current will flow freely through tube D but that substantially no current will flow through tube D, so that winding section 2? of relay F will be supplied with current but section 27 will be tie-energized. It will be seen, therefore, that the relay F is energized only when track section A.B is unoccupied, and that the polarized arn'iature of relay F is closer or open according as section I"; C is unoccupied or occupied.

As shown in the drawing, tracl: s ction (1-D is occupied by a car or train ll", so that the supply of current to transformer H is discontinued. The potential in the electron tube plate circuit-s due to trans former J is relatively low, so that the currents flowing through the windings of relay F are small when the grid circuits of tubes D and D are (lo-energized. Furthermore, the currents that flow through winding 27 and 27 of relay F neutralize each other in their etl'cct upon neutral armature 31, because these currents are substantially equal, and they flow in opposite directions through the relay winding. It should also be noted that when transformer H is (lo-energized, that is, when the grids (i are de-encrgized, tlu s rall currents in the plate circuits due to secondary 16 will flow on the positive half wave only, there being no flow in the opposite direction on the consecutive hall" waves. Relay F is, therefore, open so that signal indicates stop. Pole changer 1", which is operated by signal S", is in such position as to supply current of reverse rclative polarity to the rails of section B C. The result of this is that tube D at signal S is rendered conductive, so that"winiling section 27 of relay F is supplied with current. This causes energization of relay F in such direction that its polarized contact is open, with the result that signal S indicates caution. The pole changer P is therefore in such position that current of normal relative polarity is supplied to the rails of section i l-13, so that tube D for this section is rendered conductive. This causes winding section 27 of relay F to be energized, so that polarized contact 35 of this relay is closed, with the result that signal 8* is in the proceed posltion.

Although I have herein shown and described only one form of signaling apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim-is:

1. In combination, a section of railway track, a track circuit for said section including a source of current reversibly connected with the rails; two electron tubes each having a heated filament, a grid and a plate; a grid circuit for each tube energized from said track circuit in such manner that when the grid of either tube positive with respect to its filament the grid of the other tube is negative with respect to its filament; a plate circuit connected with a source of alternating current and provided with two branches including said two tubes respectively; a polarized relay having two difii'erential windings included in the two branches of said late circuit and si naling 7 Z: Q

means controlled by said relay.

In combination, a section of railway track, a track circuit for said section in cluding a source cl current reversiblyconnected with the rails; two electron tubes each having a heated filament, a grid and a plate; a grid circuit for each tube energized from said track circuit in such manner that when the grid of either tube is positive with respect to its filament the grid of the other tube is negative with respect. to its filament; a plate circuit connected with a source of alternating current and provided with two branches including said two tubes, respectively; and signaling means for giving one indication or another according as a substantial current flows in one branch or the other of said plate circuit.

3. In combination, a section 0'? railway track, a track circuit for said section including'a source of current reversibly connected with the rails; two electron tubes each having a heated filament, a grid and a plate; a grid circuit for each tube energized from said track circuit in such manner that when the grid of either tube is positive with respect to its filament the grid of the other tube is negative with re spect to its filament; a plate circuit con nected with a source of alternating current and provided with two branches including said two tubes, respectively; a plate circuit for each tube including a source of alternating current substantially in phase with,

or displaced 180 from the track circuit current; and signaling means for giving one indication or another according as a substantial current flows in oneroi' said plate circuits or the other.

4:. In combination, a section of railwayv track, a track circuitfor said section ineluding a source of alternating current reversibly connected with the rails, two electron tubes, a grid circuit for each tube energized from said traclr circuit, a plate circuit for each tube, said plate circuits being so connected that one plate circuit or the other is conductive according to the relative polarity of the track circuit current, a polarized relay having two differential windings included in said two plate circuits respectively, and signaling means con trolled by said relay.

5. In combination, a section of railway track, a track circuit for said section including a source of alternating current reversibly connected with the rails, two electron tubes, 9. grid circuit for each tube energized from said track circuit, a plate circuit for each tube, said plate circuits being so connected that one plate circuit or the other is conductive according to the relative polarity of the track circuit current, and signaling means controlled by said plate circuits.

6. In combination, a section of railway track, a. track circuit for said section including a source of alternating current reversibly connected with the rails, two electron tubes each having a grid circuit ar ranged to receive energy from the track circuit, two plate circuits one for each said tube, a polarized relay controlled by said plate circuits in accordance with the relative polarity of the track circuit current, and signaling means controlled by said polarized relay.

7. In combination, a section of railway t ack, a track circuit for said section in cluding a source of energy revesibly connccted with the rails, two other circuits for said section, means controlled by the relative polarity of the track circuit current in said track circuit for varying the resistances of said other circuits, a polarized relay controlled in accordance with the resistances of said two other circuits, and signaling means controlled by said relay.

8. In combination, a section of railway traclt, a track circuit for said section in- ClUCllllg a source of energy reversibly connected with the rails, two other circuits for said section, means controlled by the relative polarity of the track circuit current in saidcircuit for varying the resistances o'l said other circuits, a polarized relay comprising two differential winding sections included in said two other circuits respectively, and signaling means controlled by said rela I 9. In combination, a section of railway track, a track circuit for said section in-- eluding a source of ei'ierg'y reversibly con-- neeted vvith the rails, a polarized relay having two (lill'erentizil \vin'tlings a first electron tulle having a grid circuit receivingenergv from said track circuit and adapted to supply current to one said Winding when the track circuit current is of one relative p0" luritvr 11 second electron tlllK! having a grid circuit receiving energy from the track cir 1U cuit and adapted to supply current to the remaining relay winding when the truck circuit current is ol the other relative polarity. and signaling means controlled by said relay.

In testimony whereof I :ll'lllx' in sig'uu- 15 ture.

FRANK H. liltlllOlJSOIQ.

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