US1583766A - Cable joint - Google Patents

Description

May 4 i926. 1,583,756

y R. VV. ATKlNSON CABLE JOINT Filed NDV. 26, 19?/1.

Patented May 4, 1926..

UNITED STATESv PATENT OFFICE,

RALPH W. ATKINSON, OF PERTH AMBOY, NEW JERSEY, ASSIGNOR TO STANDARD UNDERGROUND CABLE COMPANY, F PITTSBURGH, PENNSYLVANIA, A CORPORA- TION 0F PENNSYLVANIA.

CABLE JOINT.

Application med November 26, 1924. Serial No. 752,357.

To all whom z't may concern:

Be it known that I, RAuH W. A'rxlNsoN, residing at'Perth Amboy in the county of Middlesex and State of ew Jersey, a citil zen of the United States, have invented or discovered certain new and useful Improvements in Cable Joints, of which improvements the following is a specification. i

My invention relates to improvements in the structure of joints for electric cables,

and consists in a structure, in which electrostatic strain is distributed over extended surfaces, and the surfaces themselves are so perfectly insulated, as to remove and make ll remote the danger of breakdown. My invention accordingly becomes of great practical value in the installation of high-tension cables. l

The invention is a s c' c carrying into ractice of that invenltion of Donald M.

imons which is described in a w-pcnding application of Simons, tiled November 19,v

1924, Serial No. 750,740. l

In two other pending applications of the said Simons, one of them filed September 18, 1924, Serial No. 738,424 and the other sled october 15, 1924, sel-141 ivo; 743,645, the generic invention of the said Simons is described in its adaptation to a cable joint, particularly in protecting the cut-away end of the cable-sheath, and in preventing breakdown at that point. My present invention is found in the adaptation of the same generic invention to a cable `oint, butv at another point: it is the join conductors which I protect.

My invention is illustrated in the accomanying drawings, in which Fig. I shows 'agrammatically and on a medial and longitudinal section a cable-joint, in the'structure of which the invention is embodied.

Fi II is a diagrammatic view in plan ofa s eet of material employed in the building of the joint of Fig. I.

Fig. I shows Itwo cable-ends, from which the envelope 1 of 'machine-laid insulation, and the sheath 4, have. been cut away, to

rogressively greater distances, and whose ared conductor-ends 2 have been electri-v cally united withinthe sweated-on metallic sleeve 3. l

Such a union is ordinarily wrapped in paper 'or equivalent materia, and then a joint-casing is brought to place, enclosing the whole; the joint-casing is at its ends secured to the cable-sheath, and then the structure within is flushed and the spaces within are filled with insulating compound. The problem is to protect the actual joint, and to prevent break-down from the conductorumon, through whatever dielectric may lie between, and to an adjacent metallic body. The conductor union is a point within the structure where great concentration of stress occurs, and breakdown must be prevented 05 by dielectric material of great strength properly applied.

My invention is achieved by wrapping upon the joined cable-ends a web of suitable insulatin 'material, such as paper, 70 which prefera ly in a single wrap shall form around the joined conductor-ends the insulating envelope 5. This wrapped-on web of paper is provided with a strip of metal, and the strlp of'metal is so disposed upon the web of paper that, when the paper has been applied, the metal will form the body 6, incorporated with the body 5 of' wrapped-on paper.

The step of procedure just indicated will t* be understood on comparing Fig. II with Fig. I. Fig. II shows the web of paper 9 in plan, with the strip of metal 8 in place upon it, and the-position of Fig. II relatively to Fi I is surch as to indicate the position in w ich application is made. The strip 8 extends to that ed e of the web of paper which is first applic or substantially to the edge, and in consequence the metallic strip .extended to this remote edge of the web, as it may, the body 6 would come me dially to the surface of the body 5. In that case the body 6 would on its medial crosssection be of maximum permissible diand insulation, is exact and riable and determinable.

ameter, and its equatorial radius on that medial lane would be at maximum.

Cons' ering now the resultant structure, it will be perceived. that, electrically regal-ded, the surface of the union 2,2, 3 has been extended and that the strains tending to breakdown instead of being concentrated at the stepped edge of the sleeve 3. have been diss1pated over the extended and gradually curving surface of the body 6.- And it will be observed further that, simultaneously with this extension 'of conductor surface, the superstructure of conducting material has been incorporated with a body of solid insulation, in such manner that the meeting of surfaces, as between conductor complete: there is no inter-surface space, where sparking and glowing might occur. Y

By the particular placement of the strip of metal upon the web of paper, the shape o'f the enlargement 6 of the conductor is va- Fig. I shows the shape to be that of a hollow ellipsoid7 surrounding the joint' and electrically continuous with the cable-ends adjacent the joint. And, manifestly, the ellipsoidal surface so produced, embedded as it is in the solid insulation, effects a wide and even distribution of strain; this in a structure contained within an intimately enveloping body of insulation, highly resistant to the strains exerted.

The web 9 will ordinarily be of paper. It may be formed of equivalent material, muslin, for instance, and it will ordinarily be lled wtih a suitable insulating compound, such as oil or varnish. The body built up of such material is, in its electrical character, a solid body, as distinguished from a body of liquid insulation, which in its very nature 1s not suited to withstand the strains with which we here are concerned.

The metal strip 8 borne by the web of paper or equivalent material may be variously applied: it maybe painted on the sheet, or sprayed on, or it may be vapplied in the form of foil. The sheet may itself be cut to receive the metal in the form of an inlay. The strip of .metal may be carried on one side of the web only or on bothsides or may form a section of the web, continuous from surface to surface. If it be formed by application ,to opposite surfaces, thetwo apphcations may be made electrically continuous 'by penetration through holes in th'e web of pa r. y

'dinarily in the wrapping on of the web the successive turns of the strip will make contact turn upon turn, but this is not necessary an attenuated spiral will have the same effect as a built-up ellipsoid, continuous on every meridian. -It is requisite only that the -bodyof metal be suiicient to endure under service conditions.,

rassegne Preferably, as I have said, the body 5 is built as a single wrap, in which the spirally laid laminations extend from end to end of the so-,built structure. Y x

I show the cut-away ends of the machinelaid insulation 1- to be stepped, and I show the edges of web 9 to be corespondingly cut, so that the edge of the wrapped-on body 5 makes snug contact with the'ste ped ends of the machine-laid insulation. guch minute shaping of the parts results in a structure which mamfestly is strong to endure Service.

It should hwever be remarked that in this particular the showing is. exemplary, merely; my invention lies elsewhere, and the shaping of the ends of the bodies 1 and 5, in steps or otherwise, with immediate surface-to-snrface contact or not, is a matter in which the engineer may exercise his choice, suiting his work in this respect to conditions of installation and of service.

The body 5 having ben built, the joint is in other respects completed in suitable Inan-l ner. It may be wrapped with paper and inclosed in the usual joint-casi indicated in dotted lines at 10,1`l`1g. I, and t en the structure within the casing may be flushed and all the spaces illed wtih insulating compound. The use of the invention in building the bod 5 upon the joined conductor does not for id its further use in providing the cut-away ends 4 of the cable-sheath-with extensions, as set forth in Simonss prior applications, mentioned above.

The proportions given in the drawings are necessarily ar from those which actually will obtain, and in this respect the drawin are diagrammatic. The number of turns 1n building ,the body 5 is in practice eater than the drawings suggest. vThe we may be very long, and the convergence of the opposite portions of strip 8, so clearly indicated in Fig. II, willin practical embodiment be beyond detection by casual inspection. In such matters the drawings of necessity are not to be taken as literal presentments of vthe structure.

The particular shape of the body 6 developed within the wrapped-on insulation may be varied greatly, and will in its minute shape be suited to the conditions of service contemplated.

It will be understood, without particular illustration, that the invention is applicable, without any change whatever, to each of the conductors of a multiple-conductor cable, as well as to the single-conductor cable shown,

The wrap is preferabl a single web, and in makin installation, t e application of it may readily be done in the field'.

I claim as my invention:

1. In a joint structure for electric cables, a wrapped-on body of solid insulation enveloping the joined conductors and carrying embedded within it a metallic shell in electric union with the conductor-ends adjacent embedded within it a metallic shell in electher point of union. trical union with the conductor-ends adja.-

v 2. In a ]o1nt structure for electric cables, cent their point of union. v 10 a wrapped-on body of solid insulation en- In testimony whereof I have hereunto set r veloping the joined conductors, within which my hand.

each convolution extends unbroken from end A to end of the envelope, said body carrying RALPH W. ATKINSON.

Images