US2268043A - Rail bond - Google Patents

Description

Dec. 30, 1941.. F. c. LAVARACK ETAL RAIL BOND Filed Aug. 31, 1959 wk TTORNEY w is Patented Dec. 30, 1941 RAIL BOND Frederick C; Lavarack, Montclair, N. 1., and Edward M. Deems,'Forest Hills, N. Y., assignors to Railroad Accessories Corporation, New York, N. Y., a corporation of New York Application August 31, 193 9, Serial No. 2 92.774 1 Claim. (c1. 23a 14,.1s)

This invention relates to conductors, more especiallyto conductors for connecting theadjacent ends of railway rails, particularly those for,

use in connection with railway track circuits.

It is well understood by those skilled in the railway signalling art, that a track circuit in-. cludes an isolated section or the trackway formed.

by placing insulating joints in each of the lines of rails, and by connecting a battery across the rails, at one end,'and a relay acrossthe rails at the other end. I

It is also well understood that the ordinary rail connecting or fish plates connecting the adjacent ends of the ordinary thirty foot sections are not to be relied upon to furnish suflicient conductivity for the electrical energy which flows in the rails from the battery at one end of the section to the relay at the other end thereof. This fact has necessitated a special bonding of each of the adjacent abutting rail ends, within the section.

Anoutside head of rail bond, or mechanical. head of. rail bond, asit is sometimes called, comprises a plug like body inserted in each adjacent. rail head and a conductor extending therebetween. This conductor is made of greater length than the straight line distance between plugs,

but the excess length must not be suiiicient to allow the loop to extend up onto the face of the rail because if it did so extend it would be severed by a passing rail and it must not be made of such length that it extends any considerable amount below the lower edge of the outside face of the ball or head of the rail because if it did, it would interfere with the fish plate and would likely be broken by the tracknien whenremoving and replacing a fish plate. The net result arising from the circumstance is that the bond is in length very little greater than the straight line distancebetween plugs.

Those acquainted with railway rails and their movements are well aware that due to many causes but principally to changes in temperature, abutting railends are continually approaching or separating. Approaching, even to actual contact, causes no di'iiiculty in so far as the bond is concerned but separation causes the conductor to be straightened out and a longitudinal strain placed upon it. Separation is often so great that some part of the bond must break. This break generally occurs in the conductor proper and often in that portion sometimes positioned within a sleeve at the end thereof, without causing the broken end to be pulled out of the sleeve The result is generally either an immediate or later poor contact and the track circuit fails.

A poor contact causing either anintermittent or continuous failure of the track circuit positioned within the sleeve of the end plug is a most troublesome failure because of the dimculty if not impossibility of detecting it by visual observation of a. maintainer walking along the trackway making a visual inspection of the rail head bonds. Each joint in the track circuit must be tested instrumentally at a greatexpense of time, to detect it.

A principal object of this invention is to provide a bond of suchconstructionthat it will have the desirable virtues of the specific constructions of certain prior patents and in addition will have desirable virtues not possessed by the prior forms. v

A further object of the invention is to devise a bond, especially of the type specified in which provision is made to ensure a full and complete separation between formerly attached or continuous parts when a break occurs to prevent.

intermittent failure and afford a means of easy visual detection.

,A further object of the invention is to devise a bond, especially of the type specified in which a frangible portion, or weakened portion exists, to thereby localize a break caused by undue contractionand/or separation of the abutting .rail ends.

Other objects and advantages will. appear as the description of the particular physical embodiment selected to illustrate the invention progresses, and the novel features will be particularly pointed out in the appended claim.

In describing the, invention in detail and the particular physical embodiment selected to illustrate the invention, reference will be had to the accompanying drawing and the several views thereon, in which like characters of reference designate like parts throughout the several views, and in which:

Figure l is a side elevational view of two ad jacent railway rails with a bond of our invention in place thereon; Fig. 2 is a top plan view of the device as shown by Fig. .1 and also illustrating by dotted lines a condition which arises in practice; Fig. 3 is a horizontal cross-sectional view on the plane indicated by the-line III-III of Fig. l viewed in the direction of the arrows at the endsof the line; Fig. 4 is a vertical crosssectional view on the plane indicated by line IV-IV of ,Fig. 3 viewed in the direction of the arrows at the ends of the line; Fig. 5 is a view somewhat similar to Fig. 3 but illustrating a terminal of our bond and a conductor thereof in position to be connected; Fig. 6 is a view of the conductor alone as used in our bond.

In the drawing, numeral I designates one rail and numeral 2 designates an adjacent or abutting rail of a railway track. Each of these rails has a cavity asr3 formed, in any usual or preferred manner, as by. drilling, in the outside face thereof. This cavity is of such diameter and of such depth as to just fail of encroaching upon the fissure area of the rail.

The bond itself consists, in general. of an electrical conductor 4 having a terminal at each end. This electrical conductor 4 may be made of any suitable or appropriate material and in any proper form, but it is preferred to make it as a cable formed of a plurality of electrical conducting wires with a suitable twist or helical turn to each of the separate wires so that when formed it is quite flexible and bendable. It is shown in detail in Fig. 6. Usually, it is made by cutting off the proper length from a very long cable.

After the proper length is severed the end of the cable is preferably dipped or just touched in a solder pot sufficient to coat the severed ends with solder so as to prevent the several strands of the cable from separating.

As a distant feature of our invention, after the cable is made of the proper length and the ends soldered, a groove 5 is formed near each end. This groove may be formed in any appro priate or suitable manner as by rolling or hammering. Hammering is preferred. The groove forms an area in the cable or conductor of reduced cross-section and also what I have termed a frangible portion or section in that the cable when subjected to tension is weakest at the calized grooves 5 and the cable will break at one or other of the grooves when subjected to tension before it will break at any other point.

The terminals, one at each endof the conductor, may be made of various forms but we prefer a form embodying the principles of construction as illustrated in Fig. 3 in which there is a thimble 6 for insertion in the cavity 3 of the rail head and fastenable therein by pressure exerted against a separately formed plug or pellet I.

Each terminal is provided with a sleeve, preferably formed integrally therewith and designated 8 of Fig. 3., This sleeve is split on one side, as at 9, as the sleeve is formed, in the particular form of terminal illustrated, from a sheet of metal by a drawing, pressing, forming, or stamping operation and being folded there is 'a slit 9 or abutting portions along the whole length of one side of the sleeve. The sleeve as originally made is illustrated in Fig. 5. When the sleeve is completed the conductor 4 is inserted therein and the sleeve pressed tightly down upon the conductor by any suitable or ap-- propriate means as by mating dies, and, in addition, the metal of the sleeve is pressed into the groove 5 of the conductor forming a circular protuberance i0 within the sleeve. This. construction holds the conductor firmlyand irremovably within the sleeve. Although the construction hereinbefore described is quite sufficient in many cases, it has been found that the material of the' terminal, which is commonly pure copper, in a quite malleable condition does not always have the requisite rigidity or stiffness to indefinitely securely hold-the conductor 4 within the sleev'eeven'when the inwardly protruding circular rib III is rolled, hammered or squeezed into the groove 5, so that applicants, in addition, place a sleeve ll about the sleeve 8. This is done by placing the sleeve ii about the conductor 4 loosely before the conductor 4 is fastened into the terminal and then slipping the sleeve ll over the sleeve 8 and squeezing the sleeve ll closelyz'in contact with the sleeve 8 as by mating dies or similar or appropriate methods. When the bond is prepared with the conductor 4 having a terminal on each end thereof it is aflixed to thegrails as shown in Figs. 1 and 2.

In practice, as is well understood by those skilled in this art, rails are laid with adjacent or abutting} rails in accordance with the temperature at which they are laid. In very hot weather when the steel of the rail is at a fairly high temperature the rail ends are laid closer together :than when the rails are laid when the steel is ,at a relatively low temperature. In any event after the rails have been laid, due to temperature changes and other conditions the rail ends approach one another or separate from one another. The ordinary and usual separation is provided for by the slack or excess length of the bond 4 so in ordinary practice when it has been installed it presents a loop or slack portion II as shown in Fig. 1. This loop or slack portion is of such amount that the bond conductor if tipped upwardly cannot reach the top face of the rails and so there is no danger of it being severed. It is also of such length that it does not depend any substantial amount below the lower line l3 of the outside face of the rail head so as to be in the way of a fish plate applied to the rails to fasten them together.

In most cases the slack I! provided is sufficient, n unusual conditions, occurring too frequently, the rails I and 2 contract or separate to such extent that the terminals assume a position somewhatlike that as illustrated in dotted lines in Fig. 2 and the bond wire 4 is subjected to an extremely, intense tension. This tension becomes so intense, in many cases that the weakest part of i the bond breaks. This has usually been the cable or conductor 4. If this break occurs within the sleeve 8, it results sooner or later in a failure of the electrical conductivity so that the track circuit in which the bond is placed fails. Sometimes it fails permanently and sometimes only intermittently but whether intermittently or permanently the failure is in a position which is incapable of being observed visually. The fact that the failure cannot be observed visually by a maintainer walking along beside the rail means that it is necessary to instrumentally determine the conductivity of each pair of abutting rail ends to detect the track circuit failure.

In applicants type of bond there is provided a section of the bond wire or conductor more easily frangible than any other. part of the bond so that when the bond wire is subjected to the extreme tension described the bond brealm at the groove 5 and as this groove 5 is positioned closely adjacent the outer end of the sleeve when the bond is positioned within the sleeve and as there is always a considerable elasticity in the conductor 4 even after being subjected to intense tension, when the bond 4 breaks at the frangible section it pulls out of the sleeve 8' completely and causes complete failure of the track circuit but the failure is such that the cause thereof may be easily visually detected" will be exhibited by the loose unattached end or a conductor 4.

This ability to immediately and visually detect a broken bond wire is of immense importance. In such places as railways of dense trafllc and high speed over which run excess fare trains it is necessary when a signal failure occurs by reason of the failure of the track circuit and especially a failure of the track circuit caused by a bond failure to detect the source of the difiiculty 1 in the very shortest possible time. Heretofore great delays have been caused by the inability to quickly, in fact, almost immediately detect the source of the .trouble. With applicants bond, the maintainer walking rapidly along the side 1 of the track in the section in which the failure occurred can within a very few minutes ascer-- tain that the failure is due to a broken bond if such is the case and either immediately make such temporary repair as will remove the difficulty or with full assurance can give directions for trains to proceed.

Although we have particularly described one particular physical embodiment of our invention and explained the operation, construction and principle thereof, nevertheless, we desire to have it understood that the form selected is merely illustrative, but does not exhaust the possible physical embodiments of the idea of means underlying our invention.

What we claim as new and desire to secure by Letters Patent of the United States, is; I

A. relatively short head of rail bond comprising a terminal adapted for attachment to a rail head as closely adjacent the end as practicable and formed of metal and formed with a sleeve, a conductor having one end inserted in the sleeve and formed with a reduced cross-section within the sleeve, the material of the sleeve being pressed tightly about the conductor, a terminal on the other end of the conductor adapted for attachment as closely adjacent the end of an abutting rail as practicable, said rails upon sufficiently separating causing a tension in the conductor and a breakage of the conductor at the reduced section, and said reduced section positioned so closely adjacent the outer end of the sleevethat upon so breaking it will become en tirely free of the sleeve.

FREDERICK C. LAVARACK. EDWARD M. DEEMS.

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