US2259281A - Method and apparatus for soldering connections to cable sheaths - Google Patents

Description

Oct. 14, 1941. E. wLLAMs ETAL 2,259,28l

METHOD AND APPARATUS FOR SOLDERING CONNECTIONS TO CABLE SHEATHS Filed March 6, 1941 55 INVENTORS ERNEST WLL/AMJ. Co/vsTA/VT/NE PXENAS. BY W M-W ATTORNEYS Patented Oct. 14, 1941 METHOD AND APPARATUS FOR SOLDERING CONNECTIONS TO CABLE SHEATHS Ernest Williams, Jackson Heights, and Constantine P. Xens', Little Neck, N. Y., assignors to Consolidated Edison Company of New York, Inc., New York, N. Y., a corporation of New York Application March 6, 1941, Serial No. 381354 Claims.

This invention relates to methods and apparatus for connecting grounding or bonding con: ductors to the surfaces of metallic cable sheaths. This application forms a continuation in part of our copending application Ser. No. 304,566, filed November 15, 1939, the present application being in particular directed to certain alternative methods and embodiments of the invention of said former application.

It is often necessary with lead sheathed power or communication cables to provide secure and dependable connections thereto such as for grounding thesheaths or for bonding together the sheaths of adjacent cables, etc. In View of the very heavy Currents which in the case of short circuits in power cables or for other reasons, may sometimes ,have to be carried by such connections, it is particularly important that the connection be brought into exceptionally good conductive relationship to the lead sheath. Even with good contact between the ground conductor and the sheath, there is still danger that the resistance at the area of the connection will be enough greater than the resistance of the sheath or of the ground or bonding wire, so that considerable heat will be generated at such areas by heavy short-circuit Currents. Accordngly it has been found desirable to attach the ground wire or bonding wire to the lead sheath by a relatively large mass of solder which will serve as a temporary storage means for such heat and thereby prevent melting of the lead sheath. It has sometimes been the practice to apply such large masses of solder by "wiping" on the solder at a temperature such thatit will be in a plastic condition. But such "wiping" method in general involves the same difficulties and dangers for the workmen as with the practice of forming "wiped" cable joints, as explained in our above mentioned copending application. Also the wiping" method unless skillfully performed by specially trained workmen, involves the dangers that the cable sheath may be burned" through or that the contact between the sheath and ground connection may be defective in hidden areas.

The present invention serves to overcome the above noted difiiculties and provides means for quickly applying such connections to cable sheaths, which will be uniformly dependable and which may be applied by relatively unskilled workmen without danger of melting or injuring the lead sheath.

Accoridng to the present invention, a removable mold is temporarily clamped upon the cable which, for example the bottom wall, may constitute the area on the cable sheath to which the desired mass of solder is to be applied. This area is preferably surrounded by a gasket clamped in position between the mold and the cable sheath to prevent leakage of molten solder from the mold and also if desired, to provide a certain amount of heat insulation between the hot mold and the sheath. After the mold is in place, the cavity may be filled with a mass of solder shot or pellets of such size that they may be readily sition until the solder connection is made. Upon heating the mold walls, the solder pellets will c ollapse with a wiping action against the surface of the lead sheath and the surfaces of the grounding lug or conductor, with the result that the surfaces will be smeared with the molten solder, thus insuring good contact. Then after the mass of solder becomes fully molten, the heating may be discontinued and the solder upon cooling will form an integral massive connection on the sheath and embracing the conductor.

We are aware that heretofore attempts have been made to use a sheet metal mold for similar purposes, forming a permanent part of the connection. Also with such molds it has been proposed to heat solder with a soldering iron above the mold so as to allow molten or partially molten solder to fall into the mold, and with this practice it `is attempted to again melt the solder in the mold by merely applying a soldering iron at or through the gate opening This practice; however, has numerous disadvantages and uncertainties which are overcome by the present invention. That is, a new mold was required for each connection, whereas with the present invention the mold may be made of metal such as aluminum so treated as by anodizing" the surfaces, to be non-adherent to the solder and thereore may be removed and used over and over again. Also with the practice above referred to of allowing the melted or partially melted solder to fall into the mold, it will be apparent sheath. Such mold has a cavity, one wall of 5 thatupon striking the cold lead sheath, the solder will become cooled and solidfy in irregular shapes so that it is diicult to again uniformly melt this solder in the mold, with assurance that the necessary highly dependable large area and low resistance connectionwill be provided in all cases, Without melting the cable sheath. Also once this solder has become chilled in the mold, it is difficult by using merely a soldering iron at the gate of the mold to cause the solder to be suiciently melted and smeared over the parts within the mold, for giving a good electrical and mechancally strong connection.

Various further and more specific objects and features of the invention will appear from the description given below taken in connection with the accompanying drawing which forms a part of* this specication and illustrates by way of example a preferred form of the invention. The invention consists in such novel features, methods and combinations of parts as may be shown and described in connection with the apparatus ncein disclosed.

In the drawing- Fig; l is a perspective view of a completed connection made in accordance with the inventior, between a grounding lug and the surface of a lead sheathed cable;

Figs. 2, 3 and 4 respectively are side elevation'al, plan and transverse sectional views showing' molding apparatus in accordance with the invention, as applied to a cable; and

Fig. 5 is a longitudinal sectional view through the cavity portions of the mold and the soldered connection formed thereby.

Referring now to Fig. 1, a lead sheathed cable is indicated atvlfl and the above described mass of solder serving as athermal storage means is indicated at I l, with a copper or bronze terminal as at |2 secured therein to provide a connection for receiving the end of a ground or bonding wire.

' As shown in Figs. 2-5, the molding means may include a body portion !3 adapted to be temporarily clamped to the cable, as by a metal strap |4. This strap may have one end formed with a lug |5 for engaging one or another of several slots as at IS formed in the end of another strap portion l'l, having its upper end hinged as at l8 to the under side of the mold. The other end of the strap 'l4 may have a hinged connection as at IS to a bolt 20 extending up through an opening 2| in a lug 22 formed on one side of the mold. 'I'ne upper end of the bolt 20 may be provided with a thumb nut as at 23 for tightening the clamping straps around the cable.

Before the mold is applied, the desired area for the soldered connection is preferably surrounded with a gasket as at 24, which will serve to seal the depending or fianged lower edges 25 of the moldagainst leakage of the molten solder from within' the mold. This gasket is preferably formed of somewhat resilient material capable of withstanding the temperatures of molten solder, and for reasons explained more i'ully below, also preferably being at least somewhat less conductive of heat than the adjacent metal parts. suitable known materials foi this purpose are available, iormed for example of artificial rubber and cork.

The mold may be formed with a cavity as at 26 of an area and depth suffcient for the desired thermal storages mass of solder. This cavity may preferably communicate with a relatively large gate opening 21, which will provide not only an opening through which the solder pellets may be poured, but also an opening of sufiicient size to permit insertion of the lug or terminal 12, or at least the lower portion thereof, which is tobe soldered in' contact with the lead sheath. If desired, the lower end or foot portion as at 28 of the terminal may be of suicient size so that it will not pass through the gate opening readily, except when held in a diagonal position, and thus when the mold is in place with the terminal therein, the mold will serve to retain the terminal against being displaced or pulled out by any Wire which may be attached thereto or otherwise. If desired, the terminal may be inserted through the bottom of the mold before the mold is clamped in place. i

The upper side of the mold may preferably be formed With a supporting portion as at 30, having a curved surface as at 3| (Figs. 4 and 5) eX- tending upwardly at an angle and shaped to fit' i vided at one side of the mold for the connections to the Cartridge heaters. Such cavity may have a removable cover plate as at 34 carrying quick detachable plug terminal connecting means as at 35.

After the mold is in place as shown, the mass of solder shot or pellets may be poured in through the gate opening, sufficient of the pellets being used to fill the cavity and partially fill the gate opening and thus to provide for shrinkage upon melting of the solder. suitable solder flux may also be inserted either with the solder pellets or by pouring same in before or after the pellets are in place. The electrical connections to the heating elements may now be ap plied for a predetermined time, readily determinable by trial, to insure that the solder pellets will be fullymelted into a molten mass, but insufiicientto cause any danger of melting the lead sheath. Since the heat is derived from a source vithin the mold walls, closely adjacent the solder cavity, the amount of heat thus applied may be readily controlled to avoid. endangering the lead sheath. Also it will be noted that the heat has a direct conductive path from the mold to the solder pellets, Whereas the gasket 24 serves to in sulate the sheath against the direct conduction of heat thereto. In .fact before much heat is conducted to the cable sheath, the solder pellets must first be melted so that they will collapse into good contact with the sheath, and thus the lead sheath will be substantially heated only' indirectly after the solder is molten, and at a time when the heating elements are about to be dis connected.

When the mass of solder pellets is heated, it has been found that the various pellets, as they become molten, will more or less abruptly collapse around and upon thefoot 28 of the terminal and the surface of the sheath, and thus efiectively smear these areas with solder to insure an integral bonded relationship of the parts.

The introduction of the solder into the mold in solid state and particularly in the form of pellets has various other important advantages. That is, this method avoids the use of open flames or open masses of molten solder. which are the causes of numerous accidents to the Workman, particularly with underground cable work or in other confined areas. Also with this method it is necessary to heat and to use'only the exact amount of solder which is to be embodied in the finished connection, this amount being measured by the cavity in the mold. Furthermore, with this method of heating the solder within the mold, uniform results of high quality may be quickly obtaincd despite widely different outside temperature and weather conditions, and without inconveniencing the workman with the presence of any excessive amount of heat.

The use of the mold gate opening as a space within which to insert and to retain the connecting terminal, avoids the necessity of any other opening in the mold for such purpose and around which solder might leak or escape. Furthermore, with the terminal at the gate opening, the operator may readily inspect the condition of the adjacent solder and. therefore determine whether there is a good connection before the mold is removed. Also the gate opening may be of such shape and size as to readily admit or retain terminals or connecting wires of various shapes and sizes so that special molds will be unnecessary to accommodate various different types of connections.

While the invention has been described in detail with respect to a particular preferred example, it will be understood by those skilled in the art after understanding the invention that various changes and modications may be made without departing from the spirit and scope of `the invention, and it is intended therefore in the appended claims to cover all such changes and modications.

What is claimed as new and desired to be secured by Letters Patent is:

1. The method of connecting a ground or bonding conductor to the surface of a metallic cable sheath by a mass of solder providing a thermai storage means at the connection, which comprises surrounding the area to which the desired mass is to be applied on the surface of the sheath, with a gasket, removably clamping upon said gasket a mold having a gate opening in its upper side and formed with a cavity for the mass, said cable sheath area forming an extensive wall portion of said cavity, inserting the conductor into said cavity through said gate opening, filling said cavity with solder pellets, applying heat from a source within the walls of said mold sufficient to cause said pellets to coilapse into a molten mass but insufficient to melt said sheath, and then allowing the mass to cool and thereby provide an integral massive connection on the sheath and embracing the conductor.

2. The method of soldering a conductor to a lead sheath, which comprises surrounding the area to which the solder is to be applied on the sheath with a gasket of heat insulating material, removably clamping a mold upon said gasket, heating solder to molten condition and also heating a portion of the conductor, in said mold, by applying at least the majority of the heat for such purpose to said mold, and then allowing the solder to cool to provide an integral connection for the conductor and sheath.

3. The method of soldering a ground conductor to a lead sheath, which comprises applying a mass of solder pellets to the area on the sheath where the conductor is to be secured and with a portion of the conductor in such mass, heating such mass to molten condition at temperatures insuffcient to melt the lead sheath, and then allowing such mass to cool while retaining same against displacement and with said portion of the conductor therein.

4. The method of soldering a conductor to a lead sheath, which comprises applying to the sheath a mold with a mass of solder pellets and a portion of the conductor therein, and then melting said solder by heat from an electrical resistance source within the mold structure.

5. Apparatus for connecting a ground or bonding conductor to a lead sheath comprising a mold formed of metal which is non-adherent to solder, means on said mold releasably embracing the sheath for clamping said mold on the sheath, said mold having a cavity adapted to receive a mass of solder with an area on the sheath surface forming a wall area of said cavity, electrical heating means in the walls of said mold adjacent said cavity, the mold being formedwith a gate opening to said cavity, and means adjaoent said opening for supporting the conductor with an end portion thereof extending into said cavity.

ERNEST WILLIAMS. CONSTANTINE P. XENIS.

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