US1610800A

US1610800A - Track circuit

Info

Publication number: US1610800A
Application number: US948A
Authority: US
Inventors: William H B Lavarack
Original assignee: Individual
Current assignee: Individual
Priority date: 1925-01-07
Filing date: 1925-01-07
Publication date: 1926-12-14
Anticipated expiration: 1943-12-14

Description

Dec. 14 ,1926. 1,610,800

w. H. B. LAVARACK TRACK CIRCUIT Filed Jan. 7, 1925 I INVENTOR BY 9 Z A'TI'ORNEY Patented Dec. 14, 1926.

WILLIAIVI H. B. LAVARACK,

TRACK Application filed Januar This invention relates to railway signalling, particularly track circuit signalling and more especially to the track. circuit itself.

At the present time railway signals in approved practice are controlled by means of .what is known as a track circuit. This track circuit is a unit indefinitely repeated. The unit is a section of trackway set oil from the rest of the trackway by insulating joints, usually one in each rail at each end of the section. The rails of the section at one end have a source of electrical potential connected across them. At the other end of the section a relay is connected across the track section. Just so long as a pair of Wheels connected to a common axle is not on the section the relay is energized by the source of potential sutficiently to maintain its armature in an upper position, or signal circuit closing position. If a pair of wheels connected to a common axle comes upon the section, the relay is shunted, becomes deenergized and its armature falls or opens the signal circuit.

The whole safety of the track circuit depends upon the value in ohms of the shunt made by the wheels and axle. II" this resistance is very low the arrangement is effective, if it is very high then the possibility exists that the relay armature will not respond and drop. The possibility that the relay armature will not release or drop or move to open signal circuit position is enhanced by the fact that less current is need ed to keep an armature in its upper position than is needed to raise it to that posi tion. In ordinary practice with direct current track relays, the pickup is about seventy milliamperes whereas the drop away is about thirty-live milliamperes. A given resistance shunt might well prevent an armature from being lifted but would not cause it to drop or fall.

Due to many and well known conditions i actual practice, such for instances as, rusty wheels and rails the train shunt might rise to such high value that it would not be effective to drop the relay armature but would prevent the raising of the armature if it once dropped.

In View of the hereinbefore stated considerations applicant has for a main objectthe provision of means to most certainly insure the dropping of a track circuit relay OF NORWOOD, NEVJ JERSEY.

CIRCUIT.

y 7-, 1925. serial No. 9&8.

armature upon the entrance of a train to the section to which the relay is connected. Another object of applicants invention is to provide 'ieans for actually realzing the circuit of a track circuit re ay upon tire entrance of a train to the section t6 which the relay is connected. L ther object of applic s to retain every advantage i or he )resent track circuit arrangement in connection with his new arrangement.

(,lther objects and advantages will appear as the dos: 'iption of he particular physical nbodiment selected to illustrate the ihvenion progresses, and the novel feature of the invention will be particularly pointed out in the appended claims.

In describing the invention in detail, and e particular physical embodiment selected to illustrate the invention, reference is had to the accompanying crawing, wherein l. have illustrated a particular preferred physical emoodiment of my invention, ahd wherein like characters of reference desigcorresponding parts throughout the several views, and in which:

Figure l is a schematic representation of a well known tracl: circuit with my invention applied thereto; Fig. 2, is a sectional VlGW illustrating a. conventional track in strument usable with my invention.

in Fig. 1, numeral 1 indicates one rail of a trackvv'ay and 2 the other rail. The track circuit section is set oil from the TESL of the trackway by ii'isinating joints, 3, 4-, 5 and At one end the battery 7 is connected across the rails and at the other end the relay 8 is connected across the rails. The signal 9 one ized by battery 10 through a circuit pass througl'i armature 11 controls traflic over the section. All of this construction is old and well known and is representative of standard practice with end ted direct current track circuits, which has been selected as most simple to illustrate the invention, although applicant does not mean to exclude the use of his invention with alternating current tracl; circuits, or center or oll'set feed, as it is usable with any of the commercial standard track circuits, whether the relay derives its entire energy from the track rails or not.

In 1 it will be seen that battery 7 is connected to the rails by two leads, 12 and 13 and that 13 goes through a diagrammatically indicated device 14 and emerges as 15. In the same way relay 8 is connected to the rails by

leads

16 and 17 and that 1'? passes through a similar device 1% and emerges as 18. The insertion of these devices ll in the

leads

13 and 17 is the way in which applicant expresses the idea of his invention.

The device designated as a whole by 1e conventionally illustrated by Fig. 2. The device 14: is old and well known and exists in many forms, but as no particular form is essential to the expression of applicant s invention, a conventional form merely has been illustrated. This device 1st is known as a track instrument and is merely a means whereby a passing train may by mechanical action cause a change in a circuit. in the form shown the device consists of lever 19 suitably pivoted, as to atie 20, by pin 21 and the lever by end 22 bears against rail 1. As is well understood by those skilled in railway track work, when a train passes over the rail 1 there is relative move ment between the tie 20 and the rail 1. T his movement results in depressing end 22 an raising end 23. End 23 is connected, as by link 24 to a conducting member 25 which bridges terminals 26 and 27. When end 23 rises, bridge 25 rises and disconnects 2S and 27 and so lead 1-5 and lead 13, insulation being placed at proper points as 28, 29, 30, 31 and 3-1 to prevent undesired electrical paths.

The operation of the device is quite obvious. A train entering the section in, the direction of trailic, as shown by the arrow A, would operate track instrument ll at the signal 9 and break the circuit through 1'? and 18 and so the source of potential would be entirely cut oil from the relay 3, so that the armature would have to drop regardless of the value in ohms or" the shunt formed by the wheels and axles. in short there is an absolute break in the circuit, so that the means used to drop the relay armature is absolute and positive and not marginal.

' Applicant has also shown a track instrument 14: inserted in one of the leads oi battery 7. This may or may not be done. If there is no necessity for movement against the normal direction of traffic this may be dispensed with but for complete protection it should be used because at times trains may enter the section from the end which the source of potential is positioned.

It is to be observed that although applicant has introduced into the ordinary and well known track circuit, another element, nevertheless, the track circuit may function just as it now does it the added element fails to operate. The shunt now depended upon to deenergize a track relay is just as eilective in applicants arrangement as in any track circuit. It applicants added element becomes deranged so that the circuit is broken. therethrough improperly then the failure is on the side of safety as the signal would be plz (i at danger position thereby.

Although particu 4 l nave described the construction of one physical embodiment oi my invention, and explained the operation and principle thereof, nevertheless, I desire to have it understood that the form selected is merely illustrative, but does not :haust the possible physical embodiments f the idea oi? means underlying my invention. 1 What T claim as new and desire to secure ov d Matters Patent of the United States, is:

1. In a tract circuit, in combination: rails; a source of potential connected across the i .ils at one point, a relay connected across the rails at another point and means operable mechanically by a passing train inserted in a connection of the relay for breaking the rircuit thereof.

2. In track circuit, in combination: rails; a source oi potential connected across the rails at one point; a relay connected across the rails at another point and means including a circuit controller operable mechanically by a passing train inserted in connection of the relay.

.ln a track circuit, in combination: rails; source oi potential connected across he rails at one point; a relay connected ross the rails at another point and means associated with the rail adjacent the relay Jassing train for breaking the rac circuit, in combination: urce or potential connected across one point; a relay connected across the rails at another point and means operable mechanically by a passing train for breaking the source oi potential circuit. o. in a track circuit, in combination: rails; a source of potential connected across the rails one point; a relay connected the rails at another point and means operable by a passing train tor breaking the relay circuit and means operable by a passing train for breaking the source of potential circuit.

6. in a circuit in combination: rails; a source of potential connected across the rails one point; a relay connected across the rails at another oint wh reby a pass ing train will shunt the relay and means whereby the relay circuit will be broken even if it is is not properly shunted by a train spanning the ails at its point of connection.

WllLLlAll /l H, B. LAVARACK.