US1579494A - Cable structure - Google Patents

Description

April 6 1926.

D. M. SIMONS CABLE STRUCTURE Filed March 19, 1925 FIG.I.

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UNITED STATES 1,579,494 PATENT OFFICE.

DONALD M. SIMONS, OF OSBORNE, PENNSYLVANIA ASSIGNOR TO STANDARD UNDER- GROUND CABLE COMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

CABLE STRUCTURE.

Application filed March 19, 1925. Serial No. 16,731.

To all whom it may concern:

- Be it known that I, DONALD M. SIMONS, re-

siding at ,Osborne,'in the county of Allegheny and State-of Pennsylvania,a citizen of the United States, have invented or discovered certain new and useful Improvements in Cable Structures, of which improvements the following is a specification. My invention relates to cable structure 10 and particularly to the union of successive lengths of hollow conductor, such, for example, as that shown in Letters Patent of the United States No. 873,216, granted December 10, 1907, on the application of Charles W. Davis. In Letters Patent of the United States No. 1,418,369, granted June 6, 1922, on the application of Henry W. Fisher and Ralph W. Atkinson a cable with hollow conductor is shown and described, in which the insulation is impregnated with and the hollow at the center is filled with insulating compound which, at least when applied, is liquid. Cables with hollow cores are now 1n use.

Hitherto it has not been possible-though, manifestly, it would, be very desirable, to maintain the characteristic hollow core, or ubular construction, through junction boxes, and throughout all the length of an installation. My invention consists in a connector for the conductors of hollow-conductor cables, which may be applied without obstruction of the central space. Consequently in the practice of my invention the essential hollow structure may be maintained throughout the length of installations, indefinitely. My invention is found in method also. V r

In the accompanying drawings Fig. I is a view partly in elevation, partly in medial and longitudinal section, illustrating, somewhat diagrammatically, my connector and the mode of application. Fig. II

shows the completed union.

In these drawings it suffices to show the proximate ends 1 of two insulated conductors 2. The conductors are hollow, and at their ends they extend beyond the cutaway envelopes of insulation; this for purposes of joint-making. It is these exposed conductor ends which are to be united electrically, and that without obstruction of the characteristic hollow core space within,which, in the finished installation as already. I have intimated, is commonly occupied by fluid insulation: The drawings suggest a single-conductor cable, but it will be manifest that the invention is applicable to any hollow conductor cable, whatever the number of such conductors, brought together wlthin a single cable sheath. The conductor 1s ordmarlly stranded, and consists of an annular group of wires, to which the numeral 2 is im: mediately applied, assembled upon and supported by a helix 3, commonly of steel, which defines and maintains the central hollow core.

My connector is essentially a three-part structure, and consists of two terminal thimbles 4 and a medial uniting body 5, all formed of conducting material, copper for example, and all hollow. The two thimbles 4 "are adapted to be electrically united to the two conductor ends, in the manner presently to be described; and when this has been done, the body 5 is applied. This body 5 makes screw-thread engagement with both of the thimbles 4, and the two screw threads are oppositely turned, so that by bringing the parts together and by rotating the uniting body, the whole may be iritegated and electrical connection comete p The difiiculty hitherto experienced in effecting electrical union of two such hollow conductor ends as shown in the drawings, lies in the fact that union as commonly practiced, involves the soldering to the conductor ends of a metallic connector. In soldering, the conductor ends and the connector. must be raised to a temperature exceeding the melting-point of the solder used, and, since the conductor made up as described is pervious to liquid flow, escaping solder will fill and clog the central core space. The insertion of a mandrel in the core spaces helps not at all, because by the completion of the union such an introduced mandrel would be sealed in, beyond reach'and unremovable.

' The procedure followed in the practice of my invention is indicated in Fig. I. One of the thimbles l is brought to place-upon the exposed end of one of the conductors. A mandrel 6 is then inserted, and, after the mandrel has been inserted, the thimble is soldered to place in otherwise usual manner. When union has been effected the mandrel is removed, as manifestly it may be. When the two thimbles have so been united to the conductor ends, they are brought to position with the body 5 between. The body 5 is then screwed to place'simultaneously upon "both thimbles, completing electrical union and integrating the three-piece connector. And it is apparent that the desired end is attained; {a union of hollow conductors, with uninterrupted core space through the joint.

It is manifest that this connector is available for. use in joint making generally, and that the finished union may be built within a joint structure of any preferred form.

It sometimes will be desirable to unite the hollow conductors of cables which already have been filled with liquid insulation,

. and my invention further includes provision,

by which union may be effected, without' appreciable escape ofdiquid from the conductor ends. To this end the thimbles 4 are shown in the drawings to be provided with slots 7 into which slides of proper size may be introduced, to extend temporarily across and to constitute dams across the core space. -The ends of the lengths of cable which have already before installation been filled with liquid insulation are necessarily sealed and with sealed ends the cablelengths are transported and laid. When then, within a manhole in a street, for example, two cable ends are brought together, and their conductors are to be united, the following procedure is adopted.

The extended cable-ends are brought side .by side and marked, to show where. they should be cut for joining. The cable ends are then bent, until their ends extend in vertical position. The cuts then are made and the cable sheath and the insulating envelope are trimmed back, as is usual in joint making. The thimbles 4 then are applied and soldered to place, in the manner already described. When after soldering the thimbled conductor-end has cooled, the mandrel 6 is removed, and the small extent of con ductor between the thimble and the adjacent cut-away end of insulation, to which in the drawings the numeral 8 is applied, may then be surrounded with suitable material, such as rubber or fabric, to prevent leakage. It may be that the strands of conductor at this point will be so far penetrated by solder, now solidified, that no other leakagepreventing. means are required. The upturned ends of the conductors then being flushed with insulating liquid, slides are Introduced in, the. slots 7, thecable-ends are bent back again to horizontal position, and the body. 5 applied, tounite the-thimbles 4,

in the manner already described. Holes 9 drilled in the connecting body 5 will allow the core space within the body 5 itself to be filled with liquid insulation. The slides in slots 7 may then be removed, and the slots and the filling holes may be plugged, and the desired structure is attained.

The plug or mandrel 6 employed will obviously be of such material, that it may readily be removed, after the soldering has been effected and solder has hardened upon its surface. A molded body of asbestos fibre woulld serve, or a smooth-surfaced rod of stee I have described the electrical union as being effected in the usual way, by soldering, and I have dwelt upon the past difliculties attending the soldering step, with relation to hollow "conductors. This description will be understood to be exemplary, merely. In its broader aspect, my invention is not limited to any particular way of eifecting this electrical union, and accordingly in the ensuing claims I define the invention as achieved when such union is efiected, regardless ofthe particular way of effecting it.

I claim as inv invention:

1. A connect r for hollow conductors consisting of two hollow thimbles whose walls are penetrated from the exterior to the hollow within by transverse slot, and adapted to be brought into electrical union with opposite conductor ends, and a hollow uniting body adapted to engage, to make electrical union with, and to integrate with itself the two thimbles when applied.

2. The method herein described of uniting the ends of hollow stranded conductors f an electric cable filled with liquid insulation, which consists in turning to vertical position the adjacent sealed cable ends after the lengths of cable have initially been laid in horizontal position, cutting the cable ends and exposing the conductors, applying to the exposed conductor ends hollow thimbles of conducting material and soldering the applied thimbles to place with removable core bodies introduced into the hollows within, removing the core bodies from the cooled assembly, introducing dams across the core spaces of the applied thimbles; bending the cable ends to horizontal position again, integrating the thimblesin an electrically conducting union, and removing the dams aforesaid. v In testimony whereof I have hereunto set my hand.

1 DONALD M. SIMONS/

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