US3624271A

US3624271A - Rail connectors

Info

Publication number: US3624271A
Application number: US886658A
Authority: US
Inventors: Robert H Wittman
Original assignee: HANLON AND WILSON Co
Current assignee: HANLON AND WILSON Co
Priority date: 1969-12-19
Filing date: 1969-12-19
Publication date: 1971-11-30
Anticipated expiration: 1988-11-30
Also published as: CA925978A

Abstract

Electrical continuity of end-to-end rails having expansion and contraction gaps therebetween is established by connecting devices which are wires or cables having tabs formed with connecting portions that form an angle with the rails when the tabs are seated on the rails so that they may be conveniently explosively bonded to the rails by a charge positioned on such connecting portions. The connectors may be utilized to provide electrical connection between wires or cables and metal objects other than rails.

Description

United States Patent Inventor Robert H. Wittman Arapahoe County, Colo. Appl. No. 886,658 Filed Dec. 19, 1969 Patented Nov. 30, 1971 Assignee onion 8: Wilson Company Jeannette, Pa.

RAIL CONNECTORS 22 Claims, 3 Drawing Figs.

[1.8. CI 174/94 R, 174/84 R, 238/142, 238114.12, 339/276 E, l 4 339/275 RB Int. Cl 05g 15/08 Field of Search .1 174/94;

339/275 RB, 276 E; 238114.5-14. 15; 174/84 R; 2218/3; 29/470.l, 486

[56] References Cited UNITED STATES PATENTS 2,022,544 11/1935 Huber 238/1412 2,109,791 3/1938 Carlson 238/l4.12 FOREIGN PATENTS 935,198 11/1955 Germany 238/l4.l2

Primary Examiner-Darrell L. Clay Attorney-Webb, Burden, Robinson & Webb ABSTRACT: Electrical continuity of end-to-end rails having expansion and contraction gaps therebetween is established by connecting devices which are wires or cables having tabs formed with connecting portions that form an angle with the rails when the tabs are seated on the rails so that they may be conveniently explosively bonded to the rails by a charge positioned on such connecting portions The connectors may be utilized to provide electrical connection between wires or cables and metal objects other than rails.

PATENTEDNMOIBYI 3,624,271

Flg. 2

/N VEN TOR. Roberr H. W/Hman Fig. 3 Z/ MMw/M (m/4 HIS A TTORNEY BACKGROUND This invention relates to improvements in means for providing electrical continuity along railroad rails and electrical connection to metal objects and particularly relates to a new and novel connecting device for electrically connecting railway rails end to end.

In the construction of modern railroads, it is frequently desirable to provide electrical continuity along at least one rail of a track, for example, to operate signals and other warning devices or communication equipment. Conventional railroad rails are not continuous but consist of rail segments or lengths positioned end to end. The rails do not normally abut one another, but a gap exists between each rail segment to accommodate its expansion and contraction characteristics, but such gaps interrupt the electrical continuity of the rail. Steel supporting members that bridge the gaps between the rail segments do not provide adequate electrical connection due to corrosion of the abutting surfaces and other films that effect high electrical resistance. 4

To provide electrical continuity it is conventional practice to attach opposite ends of copper wires or cable to adjacent end-to-end rails to bridge the gap between them. Conventional brazing of the ends of the wire or cable is prohibitively expensive and difficult due to the heat absorption characteristics of the heavy rail segments.

Presently the wires are connected to the rails by mechanical means, the connections are sometimes made by thermite welding techniques. Neither method is entirely satisfactory due to joint degradation (electric-current-inlhibiting corrosive films occurring between contacting surfaces) and the difficulties encountered in effecting satisfactory bonding or electrical contact under conditions of extreme cold and dampness.

THE INVENTION l have discovered that a superior rail-to-copper electrical conductor bond may be effected easily and economically under substantially any weather or moisture condition by an explosive bonding technique through the use of an electrical connector that is particularly suitable for explosive bonding techniques and which greatly simplifies rail connection. I have further devised an explosive connecting or carrying package which may be attached to the connector and which in combination therewith significantly improves both the utility of my connector and the effectiveness of its use.

My connector comprises a metal tab of special design for effective explosive bonding. Basically. the tab is provided with a body portion and a connecting portion. The body portion includes wire or cable receiving and connecting means and a surface for contacting a rail or other member to which it is to be bonded. The connecting portion has a relatively flat surface that is inclined at a preferred angle of from about 4 to from the rail-contacting surface of the body portion. By attaching the tab to a rail or other metal surface so that the surface of the body portion contacts the rail and the surface of the connecting portion faces the rail or other surface, extending at a 4 to l0 angle therefrom. it is possible to attach an explosive charge to the surface of the connecting portion that does not face the rail or other surface and effect a lasting bond by detonating the charge and forcing the connecting portion of the tab into a bonding relationship with the rail or other surface. My device is particularly useful where one of the tabs is conveniently attached to either end of a wire or cable for spanning the gap between railroad segments.

l have also found the application of the device to be significantly enhanced by providing a relatively flat surface to the connecting portion of the tabs opposite the flat surface extending 4 to l0 from the rail or the rail-contacting surface of the body portion, and attaching to this surface a container, one portion of which contains an initiation system and another portion of which contains the explosive charge. Such a container can be attached to both tabs of a tab-wire-tab arrangement and the tabs can then be attached to end-to-end rails in the manner previously described with the wire or cable spanning the gap therebetween; the explosive charges can be initiated simultaneously to effect the desired electrical connection.

DESCRIPTION OF THE DRAWINGS The present invention is best described in conjunction with the accompanying drawings wherein:

FIG. 1 is a perspective view of a tab, attached cable and explosive device (partially broken away) constructed in accordance with the preferred embodiment of the present invention;

FIG. 2 is a side elevation of the device of FIG. 1 shown attached to a member preparatory to bonding; and

FIG. 3 is a perspective view of the device of FIGS. 1 and 2 showing the tab and cable bonded to a railway rail.

In the device of FIGS. 1 and 2, tab 10 is formed with a body portion 12 and a connecting portion 14.

Body portion 12 has a cable-receiving opening 16 which is adapted to receive cable 18. As shown, cable 18 is attached to tab 10 by crimping the body portion of the tab to close opening 16 over the cable; however, cable 18 may be butt welded to the body portion or otherwise attached in known manner. Body portion 12 also has a rail-contacting surface (FIG. 2), which is not bonded to rail 22, but is designed to be seated on or near the rail surface.

Connecting portion 14 is provided with opposing

flat surfaces

24 and 26 and extends outwardly from body portion 12 at an angle 01, preferably from about 4 to 10, to rail-contacting surface 20. When the device is positioned as shown in FIG. 2, the surface 26 of the connecting portion 14 also extends at an angle a to rail 22. Thus, when placed on a rail 22, as in FIG. 2, an explosive force may be applied to the surface 24 to bond the tab to the rail as illustrated in H6. 3.

In a preferred embodiment of the present invention, a container 28 is placed on and preferably is attached to surface 24 of tab 10. Container 28 is also preferably rectangular and covers substantially the entire surface 24 of the connecting portion 14 of tab 10. If the area of the surface 24 covered by the charge is slightly less than the total area of surface 24, escaping gases generated upon explosion of the charge cannot pass into the bonding area between surface 26 and the rail 22.

Further, container 28 is preferably divided into a large compartment 30 and a small compartment 32 by a divider wall 34. An explosive charge 36 may be placed in compartment 30 and a means for detonating the charge, such as a cartridge-type detonator 38 or initiator, may be placed in compartment 32.

It should be noted that detonator 38 and compartment 32 extend transversely at the rear of container 28 rather than extending within the explosive as is conventional practice. An opening 40 in the side of container 28 permits easy insertion of the detonator 38 and attachment of an igniter 42. The igniter may be attached to the detonator 38 through a side of the container as shown, or through lid 44, whichever is more convement.

It will be readily appreciated that my tab-wire-tab arrangement with containers such as container 28 attached to either tab in the manner shown in the drawings is a particularly advantageous assembly from the standpoint of safety and convenience. Such attachment may be by means of welding or by friction tape or other convenient means prior to bonding. The tabs are then readily and efficiently bonded to end-to-end rail sections so that the wire or cable spans the gap therebetween.

Explosive charge 36 is then inserted into each compartment 30 and lid 44 applied to cover each

compartment

30 and 32. Detonator 38 can then be inserted into a compartment 32 through opening 40 (or they can be so positioned prior to applying lid 44). Igniter 42 will preferably be attached just prior to bonding.

Explosive charge 36 may be positioned in container 30 and lid 44 may be attached prior to attaching tabs 10 to the rails since in the absence of detonator 38 the assemblies may be safely handled.

The angle a formed between the flat surface 24 of the outwardly extending connecting portion 14 of the tab and the opposed surface of the rail 22 or other metal surface is a function of the area of the bond joint to be formed, the dimensions of the connecting portion of the tabs, the position of the type explosive used. It is believed that the existence of the angular space permits bonding tooccur between opposed surfaces of the tab and the rail by propagation of waves resulting from the detonation of the explosive at a point remote from the out wardly extending end of the connecting portion 14.

In practicing the invention, l have used a forged copper tab substantially of the design shown by FIGS. 1 and 2. The flat connector portion was approximately one-eighth inch thick by three-fourths inch wide by 1 inch long and was inclined at a 6 angle to the flat surface of the body portion.

The charge container 28 consisted of a plastic shell. Such a shell can be fabricated by molding, forming, or simply gluing pieces of plastic together using suitable materials including vinyl, polyethylene, cellulose acetate, etc., but also may be other materials such as cardboard. The shell wall abutting the tab surface should be no thicker than necessary to be structurally sound, but should be not more than about one-sixteenth inch thick to avoid a spacing between the tab and the explosive charge that will attenuate the explosive effect.

An explosive charge consisting of pentolite, a high explosive mixture of pentaerythritol tetranitrate and trinitrotoluene, in the proportion of 50 percent PETN, 50 percent TNT was cast into compartment 30 of the plastic shell or container 28. The dimensions of the cast explosive charge were 0.281 inch thick by 0.625 inch wide by 0.750 inch long.

The initiator for the explosive device consisted of a standard No. 6 blasting cap initiated electrically. The blasting cap was inserted into the explosive-containing plastic shell just before the explosion bond was made. The side of the blasting cap should make good contact with the cast pentolite explosive charge for reliable initiation of the explosive charge.

The plastic shell of the explosive device was attached to the flat surface of the copper tab with a suitable adhesive. Additionally, a vacuum grease may be used between the explosive device and the tab to reduce the possibility of airgaps therebetween. This assembly can be accomplished at a considerable time prior to the use of the explosion-bonded device.

To explosion bond the copper electrical connector to a steel rail, the copper connector with previously attached explosive device was affixed to a substantially flat portion of the rail with a suitable clamp. Best results are achieved, as is known, when the surfaces to be joined are free of dirt, grease, oxides or other contaminants. If not, they may be cleaned by conventional methods including grinding, sanding and the like. When the copper connector and explosive charge were properly located, the No. 6 blasting cap was inserted into the explosivefllled plastic shell. Initiation of the blasting cap detonated the explosive charge which in turn propelled the angled connecting portion of the copper tab across the airgap to collide with the steel rail at high velocity. The high-velocity angled collision resulted in the surface jetting phenomenon and bonding.

Although the preferred embodiment set forth in the drawings includes a compartmented container 28 for holding the detonator or initiator 38, such compartments are not essential and in fact in some instances may not be desirable. Further, it is not necessary that a container be used at all. Where the explosive charge is castable, divider wall 34 may be eliminated and the charge can be cast around the detonator or initiator 38.

We have had success in bonding in accordance with our invention using an electrical detonator and an explosive known as Deta s heet, a trademarked product of E. l. duPont de Nemours Co which is commercially available in relatively thin sheet form.

It is important that the detonator or initiator be positioned substantially between the explosive charge 36 and the body portion 12 of the tab so that the charge progresses outwardly along tab-connecting portion 14 to bond tab 10 to the rail or other object. In the preferred embodiment shown by the drawings, the detonator or initiator extends laterally across tab 10, but as previously stated lateral positioning is not essential. For example, where the initiator is a detonating cord, it is preferred that the cord be tied in a knot and the explosive charge be cast around the know. The knot should, of course, be positioned generally in the end of the charge adjacent the body portion 12 of the tab 10. We have had particular success in using Primacord, a trademark for detonating cord manufactured by Ensign Brickford Company.

It will be understood that the embodiments of the drawings and the example are illustrative only; for example, although the description and the example relate to the bonding of copper tabs to railroad rails, the invention is equally applicable to the bonding of tabs constructed of metals other than copper to metal objects other than railway rails.

Additionally, my invention is useful in certain applications where the surfaces of the metal object and the connecting portion of the tab to be bonded together are not perfectly flat but have some curvature. For example, electrical connectors are joined to pipe sections, which may be of cast iron material, to enable them to be thawed electrically or to prevent freezing of fluid carried by the sections. In this case, the surface of the connecting portion of my tab which is to be bonded to the contoured pipe surface is formed with a contour substantially corresponding to and complementary with the pipe surface. Of course, where the diameter of the pipe section is large compared to the complementary surface of the connecting portion to be joined thereto, 1 consider such surfaces to be substantially flat. My connector is also useful as a part of a lightning arrestor in which the tab is connected to a metal object by explosive bonding to a surface which need not be substantially flat.

1 claim:

1. A metal connector for explosive bonding to a metal object comprising:

a. a body portion having electrical connecting means and including a section forming a substantially flat surface for seating on a surface of said object;

b. a connecting portion having a substantially flat surface extending from said body portion at an angle to said seating surface; and

c. explosive means disposed on said connecting portion for explosively bonding said connecting portion to said object.

2. The connector of claim I wherein the means for explosively bonding the connecting portion to the object comprises an explosive charge adapted to be detonated on the connecting portion when the seating surface of the body portion is seated on the object.

3. The connector of claim 2 wherein the explosive charge and an initiator are received within a container positioned on a surface of said connecting portion.

4. The connector of claim 1 wherein the explosive means is positioned on a surface of the connecting portion opposite the flat surface.

5. The connector of claim 1 in which the substantially flat surface of the connecting portion extends from about 4l0 relative to the seating surface of the body portion.

6. The connector of claim 1 wherein the body and connecting portions are made of copper or a copper-base alloy, a copper or copper-base alloy wire is attached to the body portton.

7. Apparatus for forming an electrical connection between the gap of end-to-end railway rails comprising:

a. an electrically conductive wire or cable;

b. a tab attached to each end of the wire cable, each said tab having a body portion and a connecting portion;

1. said body portion having a section forming a substantially flat seating surface for seating on a surface of one of said rails;

2. said connecting portion being formed with a substantially flat surface extending from said body portion at an angle from said seating surface of said body portion; and

3. explosive means disposed on said connecting portion for explosively bonding said connecting portion to said rail.

8. The apparatus of claim 7 wherein each said tab has a container attached to the surface of said connecting portion, said containers having at least one compartment receiving said explosive means 9. The connector of claim 7 wherein the substantially flat surface of said connecting portion extends from about 4-l0 relative to the seating surface of said body portion.

10. Apparatus as set forth in claim 7 wherein the wire or cable and the tab are each formed of a copper or copper-base alloy material.

11. A metal connector for explosive bonding to a metal object comprising:

a. a body portion having electrical contacting means and including a section forming a seating surface adapted for seating on a surface of said object;

b. a connecting portion having a surface extending from said body portion at an angle to the seating surface of the body portion and substantially complementary to the surface of the object to which the connecting portion is to be bonded; and y c. explosive means disposed on said connecting portion for explosively bonding said connecting portion to said object.

12. The connector of claim 11 wherein said explosive means for explosively bonding said connecting portion to said object comprises an explosive charge adapted to be detonated on said connecting portion when said body portion is seated on said object.

13. The connector of claim 12 wherein the explosive charge and an initiator are received within a container positioned on a surface of said connecting portion.

14. The connector of claim 13 wherein the initiator is positioned within said container substantially adjacent said body portion.

15. The connector of claim 11 wherein the explosive means is positioned on a surface of the connecting portion opposite the complementary surface.

16. The connector of claim 11 in which the complementary surface of the connecting portion to be bonded extends from about 4-l0 relative to the seating surface complementary to the surface of said object.

17. A metal connector for explosive bonding to a metal object comprising:

a. a body portion having electrical connecting means and including a section forming a substantially flat surface for seating on a surface of the object;

b. a connecting portion having a substantially flat surface extending from said body portion at an angle to said seating surface such that an explosive charge detonated on the connecting portion when the body portion is seated on the object will drive the connecting portion to bond with the object;

0. a container for receiving an explosive charge and an initiator being positioned on a surface of the connecting portion substantially opposite said substantially flat surface; and

d. an explosive charge and an initiator being positioned within said container.

18. The connector of claim 17 wherein said container is formed with two compartments one being adjacent said body portion receiving said initiator and the other extending over said substantially flat surface receiving said explosive charge.

19. The connector of claim 18 wherein said container, compartments, and connecting portion are substantially rectangular in shape and the compartment adjacent said body portion extends laterally across said connecting portiom The connector of claim 19 wherein the mrtrator extends laterally across said connecting portion in said compartment adjacent said body portion and the explosive charge is positioned in the compartment extending over said substantially flat surface.

21. The connector of claim 19 wherein said container is formed with an opening in the side thereof leading to the compartment for receiving the initiator so that said initiator may be inserted into said compartment through said opening 22. The connector of claim 17 wherein said initiator is embedded within said explosive charge.

Claims

1. A metal connector for explosive bonding to a metal object comprising: a. a body portion having electrical connecting means and including a section forming a substantially flat surface for seating on a surface of said object; b. a connecting portion having a substantially flat surface eXtending from said body portion at an angle to said seating surface; and c. explosive means disposed on said connecting portion for explosively bonding said connecting portion to said object.

2. The connector of claim 1 wherein the means for explosively bonding the connecting portion to the object comprises an explosive charge adapted to be detonated on the connecting portion when the seating surface of the body portion is seated on the object.

5. The connector of claim 1 in which the substantially flat surface of the connecting portion extends from about 4* - 10* relative to the seating surface of the body portion.

6. The connector of claim 1 wherein the body and connecting portions are made of copper or a copper-base alloy, a copper or copper-base alloy wire is attached to the body portion.

7. Apparatus for forming an electrical connection between the gap of end-to-end railway rails comprising: a. an electrically conductive wire or cable; b. a tab attached to each end of the wire cable, each said tab having a body portion and a connecting portion;

8. The apparatus of claim 7 wherein each said tab has a container attached to the surface of said connecting portion, said containers having at least one compartment receiving said explosive means.

9. The connector of claim 7 wherein the substantially flat surface of said connecting portion extends from about 4* - 10* relative to the seating surface of said body portion.

11. A metal connector for explosive bonding to a metal object comprising: a. a body portion having electrical contacting means and including a section forming a seating surface adapted for seating on a surface of said object; b. a connecting portion having a surface extending from said body portion at an angle to the seating surface of the body portion and substantially complementary to the surface of the object to which the connecting portion is to be bonded; and c. explosive means disposed on said connecting portion for explosively bonding said connecting portion to said object.

16. The connector of claim 11 in which the complementary surface of the connecting portion to be bonded extends from about 4*-10* relative to the seating surface complementary to the surface of said object.

17. A metal connector for explosive bonding to a metal object comprising: a. a body portion having electRical connecting means and including a section forming a substantially flat surface for seating on a surface of the object; b. a connecting portion having a substantially flat surface extending from said body portion at an angle to said seating surface such that an explosive charge detonated on the connecting portion when the body portion is seated on the object will drive the connecting portion to bond with the object; c. a container for receiving an explosive charge and an initiator being positioned on a surface of the connecting portion substantially opposite said substantially flat surface; and d. an explosive charge and an initiator being positioned within said container.

19. The connector of claim 18 wherein said container, compartments, and connecting portion are substantially rectangular in shape and the compartment adjacent said body portion extends laterally across said connecting portion.

20. The connector of claim 19 wherein the initiator extends laterally across said connecting portion in said compartment adjacent said body portion and the explosive charge is positioned in the compartment extending over said substantially flat surface.

21. The connector of claim 19 wherein said container is formed with an opening in the side thereof leading to the compartment for receiving the initiator so that said initiator may be inserted into said compartment through said opening.

22. The connector of claim 17 wherein said initiator is embedded within said explosive charge.