US2356453A - Control apparatus for highway crossing signals - Google Patents

Description

Aug. 22, F. T. FERED Y CONTROL APPARATUS FOR HIGHWAY CROSSING SiGNALS 5 Sheets-Sheet 1 Filed March 10,1942

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I 2 01 00 0? BY H49 ATTORNEY 8 2 4- F. T. FEREDIYAY 2,356,453

CONTROL APPARATUS FOR HIGHWAY CROSSING SIGNALS Filed March 10, 1942 5 Sheets-Sfieet 2 Aug. 22, 1944. F. T. FEREDAY conmounmnnus FOR HIGHWAY CROSS-1N6 SIGNALS 5 Sheets-Sheet 4 Filed March 10, 1942 Aug. 22, 1944. F, "r. FEREDAY CONTROL APPARATUS FOR HIGHWAY CROSSING SIGNALS 5 Shets-Sheet 5 Filed March 10, 1942 Patented Aug. 22, 1944 CONTROL APPARATUS FOR HIGHWAY CROSSING SIGNALS Frederick T; Fereday, Louisville, Ky., assignor to The Union Switch and Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application March" 10, 1942, Serial No. 434,037

" 8 Claims. (01. 175-373) My invention .relates to control apparatus for highway crossing signals, and particularly to apparatus for effecting the alternate flashing of warning lights at a highway-railway crossing when a train approaches the highway to warn users of the highway that the train is approach- One object of my invention is to provide apparatus of the type described in which all heavy currents are at all times controlled by mercury contacts.

Another object of my invention is to incorporate the control apparatus into a relatively compact unitary structure.

According to my invention, the apparatus C0171".

prises a relay structure including a. control magnet, a selector magnet, and a main flasher magnet all mounted on an insulating supporting panel or top plate. The control and flasher magnets are each provided with pivoted armatures disposed on the underside of the top plate, and pivotally supported from the top plate between these two armatures is a rocker which carries a pair of mercury contacts. This rocker is biased to one extreme position in which the one contact is closed and the other is open, and is operatively connected with the armature f the flasher magnet by suitable linkage in such manner that when this armature is released, the rocker is free to move due to its bias to its one extreme position, but that, when this armature occupies its attracted position, the rocker is moved from its oneextreme position to another extreme position in which the one contact is open and the other contact is closed. This rocker is also operatively connected with the armature of the control magnet in such manner that when this armature occupies its attracted position, the rocker is moved in opposition to its biasto' an intermediate position in which both mercury contacts are open. The selector magnet is provided with two windings and controls a contact which is moved to a closed or open position according as one winding or the other becomes energized. When the control relaybecomes deenergized, it completes energizing circuits for the selector and flasher magnets including the contact of the selector relay and front and'back contacts cons trolled by the flasher magnet armature, whereby the flasher magnet is caused to become alternately energized and deenergized, and thus oscillate the rocker between its two extreme positions. The mercury contacts eachcontrol a difierent lamp ,of the usual highway crossingsignal, whereby when the rocker is oscillating, the lamps are alternately flashed.

Other, objects and characteristic featuresof my invention will become apparent as the description proceeds.

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

In the accompanying drawings, Fig. 1 is a diagrammatic view showing one form of control apparatus for highway crossing signals, which control apparatus embodies my invention. Figs. 2, 3, 4 and 5 are top plan, front elevational, rear elevational and bottom views, respectively, of a relay structure forming partof the control'apparatus shown in Fig. 1 and embodying my invention. Fig. 6 is a longitudinal sectional view of one of the mercury contacts employed in the relay structure shown in Figs. 4 and 5. Fig. 7 is a bottom view of the selector magnet forming part of the relay structure shown in Figs. 2, 3, 4 and 5. 7

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

Referring first to Fig. 1, the reference characters and la designate the track rails of a stretch of railway track which is intersected by a highway H, and over which traiiic normally moves in both directions. The, track rails l and la are divided, by means of insulated joints 2, to form two track sections D--E and EF, the junction of which is located ator near the highway H, and each of these sections is provided with a track circuit comprising the rails of the section and a track battery 3 connected across the rails at the end farthest from the highway. The track circuit for section D--E also comprises one magnet 4a ofan interlocking relay, which magnet is connected across therails l and la of the section at the end nearest the highway, while the track circuit for section EF similarly also comprises the other magnet of the relay L connected acrossthe rails ofthe section at the end nearest the highway. y The interlocking relay L may be of any suitable type, suchior example, asthe relay described and claimed in Letters Fatent of the United States ;No. 1,799,629, granted to William K. Lockhart and Thomas J. OMeara on April 7, 1931. This type of relay is. well known, and includes amechanical locking device which is effective if both electromagnets become deenergized to prevent the armature of the electromagnet last to become deenergized from dropping. past approximately its intermediate position, frequently termed its locked position. The relay as shown is provided with a front contact a controlled by magnet 4a, and a front contact 517 controlled by magnet 4b. These contacts are so adjusted that they will remain closed when the associated armature is in its locked position, and in actual practice these contacts are usually termed flagman contacts.

Located adjacent the intersection of the railway and the highway is a highway crossing signal S, the function of which is to give a warning indication when a train is approaching the highway from either direction. This signal, as here shown, is of the well known flashing light type, and comprises two lamps RI and R2 adapted to be alternately energized or flashed at the rate of thirty-five to forty-five times per minute to simulate the appearance of a horizontally swinging red light.

The signal S is controlled by the interlocking relay L through the medium of a relay structure designated as a whole by the reference character FR, and embodying my present invention. Referring now to Figs. 2 to 7, inclusive, this relay structure in the form here shown comprises a control magnet CM, a flasher magnet FM, and a selector magnet SM all mounted. on a top plate 6 of suitable insulating material such as Bakelite. The control magnet and the flasher magnet are similar, and each comprises a pair of parallel cores la and 11) connected together at their upper ends by a backstrap 8, and terminating at their lower ends in enlarged pole pieces 9a and 9b disposed underneath the top plate. The cores la and lb are surrounded by energizing windings a and lllb connected by suitable leads to binding posts ll mounted on the top plate 6, whereby these windings may be included in suitable control circuits such for example as those shown in Fig. l, which circuits I shall describe presently.

A tractive armature I2 is pivotally mounted for swinging movement toward and away from the pole pieces 9a and 9b of the control magnet CM by means of trunnion screws l 3 mounted in a nonmagnetizable bracket l4 secured to the left-hand sides of the pole pieces, as viewed in Fig. 3. The armature is prevented from actually touching the pole pieces by means of non-magnetic stops or core pins l5, and its movement away from the pole piece is limited by a stop arm [6 secured to a depending post I! mounted on the top plate. When the armature I2 is moved to its attracted position, an arm l8 secured to, but insulated from the armature, engages a flexible contact finger l9 and moves it out of engagement with a fixed contact member to open a back contact [9-29. The flexible contact finger I9 is secured to a terminal post 2! mounted on the top plate 6, and is biased by its own resiliency to the position in which it engages the fixed contact member 20 to close the contact [9-20. The fixed contact member 20 is secured to a terminal post 22 mounted on the top plate 6.

The flasher magnet controls a tractive armature 25 which is mounted for swinging movement toward and away from the pole pieces 9a and 9b of this magnet in the same manner that the armature I2 is supported for swinging movement toward and away from the pole pieces 90. and 9b of the magnet CM. Secured to, but insulated from the armature 25 is a contact arm 26 which cooperates With a fixed front contact member 26a, or a fixed back contact member 26b, to close a front contact 26-26a or a back contact 26- -26!) according as the armature 25 is picked up or released. The fixed front and back contact members 26a and 2622 are secured to terminal posts 21 and 28, respectively, mounted in the top plate 6.

A horizontal shaft 3i is pivotally suspended from the top plate 6 approximately midway between the armatures l2 and 25 by means of an inverted U-shaped bracket 32, and secured to one end of this shaft by means of a yoke 33 and two spacing studs 34 and 35 is an insulating rocker 36. This rocker is biased by a counterweight 31 to an extreme position in which the one corner 38 engages the underside of the top plate, and is operatively connected, by means of a pin 39 and an arm 40, with the armature 25. The pin 39 is secured tothe rocker in laterally spaced relation with respect to the axis of rotation of the rocker, and extends with clearance through a hole 4l formed in one end of the arm 40. The arm 40 at the end opposite to the hole 4| is secured to the armature 25 by means of an angle bracket 42. The parts are so proportioned that when the armature 25 is released, the rocker is free to move due to its bias to its biased extreme position, but that, when the armature is picked up, the rocker will be moved in opposition to its bias to an opposite extreme position.

The rocker is also operatively connected with the armature [2 by means of a rigid arm 43 which is secured at one end to the armature l2, and which is provided at the other end with a laterally extending pin 43a which extends underneath the yoke 33. The parts are so proportioned that when the armature I2 is released, the rocker is free to move due to its bias to its biased extreme position, but that, when the armature I2 is picked up, the pin 43a will cooperate with the yoke 33 to prevent the rocker from moving due to its bias past an intermediate position in which its longitudinal axis is substantially horizontal.

A pair of mercury contacts 45 and 46 are secured to the rocker 36 by means of contact clips 41. These contacts may be of any suitable type, but as here illustrated (see Fig. 6) each of these contacts comprises a cylindrical iron cap 45a insulated from a cylindrical iron body 451) by a resilient bushing 450, which bushing also insulates a refractory breaker 45d, which is disposed inside of the cap, from the cap. The chamber formed inside of the assembly is partly filled with mercury, and the parts are so proportioned that when the contact is horizontal or the cap end is raised above the horizontal, the mercury will be separated into two parts by the breaker to thereby disconnect the cap from the body. When, however, the cap end is lowered, the mercury spills over the breaker and electrically connects the cap and body.

The contact clips at one end of the contacts are both connected to a flexible wire 49, while the two clips at the opposite ends of the contacts are separately connected to flexible wires 50 and 5|. The wires 49, 50 and 5| extend through an axial hole 52 formed in the rocker 36, and are secured to terminal posts 52, 53 and 54, respectively, mounted on the top plate 6.

The selector magnet SM is mounted on the upper side of the top plate 6 between the two magnets CM and FM, and in the form here shown comprises two parallel cores 56 and 5l connected together at their upper ends by a backstrap 58, and surrounded by energizing windings 59 and 60. The lower ends of the cores are provided with enlarged pole pieces GI and 62 secured to the cores by means of screws 63 and 64, which screws pass through the top plate and serve as a means for securing the magnet as a whole to the top plate. A magnetizable armature 55 is pivotally attached to the backstrap 58 between the cores for swinging movement toward one pole piece or the other, and this armature carries a flexible contact finger 66, which when the armature is swung toward the pole piece 6|, engages a fixed contact member 61 to close a contact 66-61. The fixed contact member is adjustably mounted in the lower end of an angle bracket 68 secured by means of a terminal post 59 to a terminal board 16 attached to the back strap 58 by means of the same screws which fasten the backstrap to the cores 56 and 51. One terminal of the energizing winding 59 is also secured to the terminal post 69, while the other terminal of this winding is secured to a terminal post 1 I mounted on the terminal board. The terminals of the winding 60 are secured respectively to the terminal post H and to another terminal post 12 mounted on the terminal board. It is desirable for a purpose which will appear presently to be able to adjust the time characteristics of the selector magnet, and to this end the pole pieces are bridged by a shunt bar 13 (Fig. '7) secured to the pole pieces by screws 14 and 15 which pass through clearance holes in the shunt bar and are screwed through tapped holes provided in the pole piece. An adjusting screw I6 is screwed through a threaded hole in the shunt bar opposite the pole piece 62, and bears at its inner end against the side of this pole piece, whereby the magnetic coupling between the shunt bar and the pole pieces may be varied.

Referring now again to Fig. l, the operation of the control apparatus as a whole is as follows. As shown in the drawings, track sections D-E and E--F are both unoccupied, and magnets 4a and 4b of interlocking relay L are therefore both energized. Under these conditions, magnet CM is energized over a circuit which passes from one terminal B of a suitable source of current not shown in the drawings through contacts b and 5a of relay L and the winding'of magnet CM to the other terminal C of the same source. Armature i2 is therefore held in its attracted position in which contact Iii-20 is open, and rocker 35 is held in its intermediate position in which contacts 45 and 66 are open. All energizing circuits for magnets FM and SM are controlled by the contact Ill-40, and since this contact is open, these magnets are both deenergized. The lamps RI and R2 are likewise both deenergized since the energizing circuits for these lamps are controlled by the contacts 45 and 46.

I shall now assume that a train moving from left to right, as viewed in Fig. 1, enters section DE. The entrance of the train into this section causes magnet 4a, to become deenergized, and contact 5a therefore becomes opened and interrupts the energizing circuit for magnet CM. This causes armature l2 to drop, and hence permits rocker 36 to move, due to its bias, to its biased extreme position, whereupon mercury contact 45 becomes closed and completes a circuit for lampjRl which circuit will be obvious from an inspection of the drawings. Lamp 'Rl will therefore immediately become lighted. The dropping oi armature l2 also causes contact |9-26 to become closed, and when this contact becomes closed, a circuit is completed for windings 59 and 66 of magnet SM passing from terminal B through contact |9--26, and the windlugs 59 and 66 of magnet SM in series to terminal C. Due, however, to the fact that magnet FM is deenergized, winding 60 is short circuited by back contact 26-26b of magnet FM, and only the winding 59 therefore becomes energized. The energization of winding 59 causes the armature of magnet SM to swing toward pole piece 5| which closes contact 66--6'l. The closing of this contact completes a circuit for magnet FM passing from terminal B through contact l9-20 of magnet CM, contact 566l of magnet SM, and the winding of magnet FM to terminal C. Armature 25 of magnet FM thereupon moves to its attracted position, which movement rotates rocker 36 in opposition to its bias from its biased extreme position to its opposite extreme position, thereby opening contact 45 and closing contact 46. The opening of contact 45 interrupts the circuit for lamp RI, while the closing of contact 66 completes a circuit for lamp R2, which latter circuit will also be obvious from an inspection of the drawings. Lamp RI thereupon becomes extinguished and lamp R2 becomes lighted. The movement of armature 25 to its attracted position also opens contact 26-262) and closes contact 2626a. The closing of contact 26--26a short circuits winding 59 and the field set up in the core of this winding commences to decay. Due, however, to the snubbing efiect of the short circuited winding and to the presence of the shunt bar this decay is comparatively slow. The opening of contact 2626b in the meantime has allowed winding 60 to become energized. The growth of the field set up in the associated core by the energization of this winding is comparatively slow due to the magnetic shunt, but after an interval of time the torque exerted on armature 65 by this field overcomes the opposing torque exerted by the decaying flux, and armature 65 then swings toward pole piece 62. This opens contact 6667 which deenergizes magnet FM and allows armature 25 to drop. The dropping of this armature permits rocker 36 to return to its biased extreme position, which extinguishes lamp R2 and relights lamp RI. The dropping of this armature also opens contact 2626a and closes contact 2626b, thereby removing the short circuit from winding 59 and reestablishing the short circuit for winding 60. The field of winding 59 then slowly builds up and the field of winding 60 slowly decays, and eventually armature 65 will again swing toward pole piece 6|, which will reclose contact 66-451 and thus reestablish the circuit for magnet F'M, so that armature 25 will again pick up. It will therefore be apparent that armature 25 will continue to alternately pick up and release as long as contact l926 remains closed, to thereby cause the lights RI and R2 to be alternately lighted or flashed. It will also be apparent that the rate of flashing can be controlled by varying .the adjustment of the shunt bar 73, and if Ithe desired rate is too fast, it can be slowed down by providing the windings of the magnets FMand SM with slow acting sleeves, or by providing snubbing washers on the cores of these magnets in accordance with well-known practice. Contact |9--20.will remain closed until the train vacates section D-E, whereupon the resultant energizaton of magnet do will close contact 5a and will reestablish the circuit for magnet CM since contact 5b will remain closed even though section EF is now occupied due to the interlocking structure of the relay and the contact adjustment described hereinbefore. When contact 19-26 opens, all parts of relay structure-FR will be restored to the positions in which they are shown in Fig. 1.

When a train approaches the crossing from the right as viewed in Fig. 1, the operation of the apparatus will be similar to that just described with the exception that under these conditions the relay structure will be set into operation by the opening of contact 52) of relay L.

It should be particularly pointed out that with the relay structure FR constructed in accordance with my invention, the lamp circuits are controlled entirely by the mercury contacts 45 and 46, which eliminates the necessity for any of the other contacts to be constructed to carry heavy currents. This is a distinct advantage where a crossing is provided with several signals the lights of which are flashed in unison, as is now common practice, since under these conditions the current flowing in the lamp circuits becomes too large to be controlled by ordinary relay contacts.

Although I have herein shown and described only one form of control apparatus for highway crossing signals 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 pivoted contact carrying a rocker movable between two extreme positions, a first magnet, means controlled by said first magnet and effective when said first magnet is energized for moving said rocker in opposition to its bias to an intermediate position, a second magnet, means controlled by said first magnet and effective when said first magnet is deenergized for causing said second magnet to become alternately energized and deenergized at a predetermined rate, and means responsive to alternate energization and deenergization of said second magnet for oscillating said rocker between its two extreme positions.

2. In combination, a pivoted rocker movable between two extreme positions and biased to one extreme position, a first magnet, means controlled by said first magnet for moving said rocker to an intermediate position in opposition to its bias when said first magnet is energized, a second magnet, means controlled by said first magnet for periodically energizing and deenergizing said second magnet when said first magnet is deenergized, means controlled by said second magnet for oscillating said rocker between its two extreme positions in response to periodic energization of the magnet, and contacts selectively controlled by said rocker in accordance with its position.

3. In combination, a pivoted rocker movable between two extreme positions and biased to one extreme position, a first magnet, means controlled by said first magnet for moving said rocker to an intermediate position in opposition to its bias when said first magnet is energized, a second magnet, means controlled by said first magnet for periodically energizing and deenergizing said second magnet when said first magnet is deenergized, means controlled by said second magnet for oscillating said rocker between its two extreme positions in response to periodic energization of the magnet, and mercury contacts secured to said rocker and operated thereby.

4. In combination, a pivoted rocker movable between two extreme positions and biased to one 75 extreme position, a first magnet, means controlled by said first magnet for moving said rocker to an intermediate position in opposition to its bias when said first magnet is energized, a second magnet, means controlled by said first magnet for periodically energizing and deenergizing said second magnet when said first magnet is deenergized, means controlled by said second magnet for oscillating said rocker between its two extreme positions in response to periodic energization of the magnet, and a pair of mercury contacts secured to said rocker in such manner that one contact is closed when and only when said rocker occupies its one extreme position and the other contact is closed when and only when the rocker occupies its other extreme position.

5. In combination, a control magnet, a selector magnet and a flasher magnet all mounted on an insulating supporting member, a first armature associated with said control magnet, a second armature associated with said flasher magnet, a pivoted rocker pivotally mounted on said supporting member for movement between two extreme positions and biased to one extreme position, a first arm secured to said first armature and operatively connected with said rocker in such manner that movement of said first armature to its attracted position will move said rocker to its intermediate position in opposition to its bias, a second arm secured to said second armature and operatively connected with said rocker in such manner that said rocker will be moved to its other extreme position when said second armature is picked up and will be free to move to its one extreme position when said second armature is released if said first armature is then also released, a contact controlled by said first armature and closed when said first armatureis released, circuits for said control and flasher magnets controlled by said first contact, and contacts controlled by said second armature and by said selector magnet and included in said circuits for causing said flasher magnet to become alternately energized and deenergized as long as the contact controlled by said first armature is closed.

6. In combination, a control magnet, a selector magnet and a fiasher magnet all mounted on an insulating supporting member, a first armature associated with said control magnet, a second armature associated with said flasher magnet, a pivoted rocker pivotally mounted on said supporting member for movement between two extreme positions and biased to one extreme position, a first arm secured to said first armature and operatively connected with said rocker in such manner that movement of said first armature to its attracted position will move said rocker to its intermediate position in opposition to its bias, a second arm secured to said second armature and operatively connected with said rocker in such manner that said rocker will be moved to its other extreme position when said second armature is picked up and will be free to move to its one extreme position when said second armature is released if said first armature is then also released, a contact controlled by said first armature and closed when said first armature is released, circuits for said control and flasher magnets controlled by said first contact, contacts controlled by said second armature and by said selector magnet and included in said circuits for causing said fiasher magnet to become alternately energized and deenergized as long as the contact controlled by said first armature is closed,

and a pair of mercury contacts secured to said rocker in such manner that one contact is closed when and only when said rocker occupies its one extreme position and the other contact is closed when and only when the rocker occupies its other extreme position.

7. In combination, a pivoted rocker movable between two extreme positions and biased to one extreme position, a first and a second magnet, means controlled by said first magnet for moving said rocker to its intermediate position in opposition to its bias when said first magnet is energized, means for moving said rocker to its other extreme position when said second magnet is energized, a two winding selector magnet, a first contact closed when one winding of said selector magnet is energized and opened when the other winding is energized, a second contact closed only when said first magnet is deenergized, a third contact closed when said second magnet is energized, a fourth contact closed when said second magnet is deenergized, a first circuit including said second contact and the two windings of said selector magnet in series, means controlled by said third contact for at times short circuiting said one winding of said selector magnet, means controlled by said fourth contact for at times short circuiting said other winding of said selector magnet, and a circuit for said flasher magnet controlled by said first and second contacts.

8. In combination, a pivoted rocker movable between two extreme positions and biased to one extreme position, a first and a second magnet, means controlled by said first magnet for moving said rocker to its intermediate position in opposition to its bias when said first magnet is energized, means for moving said rocker to its other extreme position when said second magnet is energized, a two winding selector magnet, a first contact closed when one winding of said selector magnet is energized and opened when the other winding is energized, a second contact closed only when said first magnet is deenergized, a third contact closed when said second magnet is energized, a fourth contact closed when said second magnet is deenergized, a first circuit including said second contact and the two windings of said selector magnet in series, means controlled by said third contact for at times short circuiting said one winding of said selector magnet, means controlled by said fourth contact for at times short circuiting said other winding of said selector magnet, a circuit for said flasher magnet controlled by said first and second contacts, and a pair of mercury contacts secured to said rocker in such manner that one contact is closed when and only when said rocker occupies its one extreme position and the other contact is closed when and only when the rocker occupies its other extreme position.

FREDERICK T. FEREDAYK

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