US2759256A

US2759256A - Method and blank for securing a cable repair sleeve to a cable

Info

Publication number: US2759256A
Application number: US293360A
Authority: US
Inventors: Martin D Bergan
Original assignee: Thomas and Betts Corp
Current assignee: ABB Installation Products Inc
Priority date: 1952-06-13
Filing date: 1952-06-13
Publication date: 1956-08-21
Anticipated expiration: 1973-08-21

Description

Aug. 21, 1956 M D, BERGAN 2,759,256

METHOD AND BLANK FOR SECURING A CABLE REPAIR SLEEVE TO A CABLE Filed June 13, 1952 1NVENToR- MARTIN D. BEFQGQN WWUQQz/gw United States Patent O METHOD AND BLANK FR SECURING A CABLE REPAIR SLEEVE TO A CABLE Martin D. Bergan, Westfield, N. J., kassigner to The Thomas & Betts Co., Elizabeth, N. J., a corporation of New Jersey Application June 13, 1952, lSerial No. 293,360

8 Claims. (Cl. 29-S15) The invention relates -to a 'cable repair tube or sleeve for use in reinforcing a worn, damaged or otherwise defective electric conductor and to the method of installing the sleeve in place on the conductor. The `conductor cable is made up of a multiple of wires some of which ,at times are broken or damaged.

1t is a practical and economic requirement vof repair sleeves that they be manufactured complete as far as possible 'as a factory-produced article -of manufacture and that they be vdesigned so that in install-ing them on the conductor to be repaired they will require that Lthe least possible work be done `on them in the -eld installation tto effect the requisite permanent connection with the conductor.

The securing of repair sleeves to .conductors already in place and .usually in .an outside location .often high in zthe air is usually elfected `by means .of a hand-operated .crimping tool which, `of course, imposes a limitation :on the power `available -to crimp ,the Sleeve. The difficulty in making a secure connection between repair sleeve and the ,conductor increases, of course, with the size of .the sleeve and with large size ,conductors `and repair sleeves power-actuated .crimping apparatus wmust be used.

The .primary object .of .the invention is to provide a repair sleeve by means of which a defective cable Vor with broken wires may 'be reinforced .and strengthened in its defective area .and which sleeve may be installed by ,a manually powered crimping operation, even in lthe case of conductors which may be designed in the trade as of large size.

Broadly, this objective is attained by forming .the repair sleeve 1as .an article of manufacture, preferably as a ,casting, U-,shaped in Vcross section .and .in Ywhich its .crotch portion is preformed to `the eventual `configuration :of .the finally completed sleeve, .and thus `does not have t become involved in the subsequentcrimping operation and wherein 4the available manual power of the operator or the power inherent in a small Size kp,o-weraoperated tool is utilized solely to yeffect an inwra,pping of .the relatively soft leg portions 'in binding the sleeve to .the conductor.

In those `cases where the available .crimping pressures, either manually or .power-actuated, Vacting Qn the sleeve are sucient 4to `do so, the invention contemplates the work-hardening of the legs as they are .in-wrapped about the conductor seated in the preformed crotch portion of the sleeve.

In this art it has been found .to 'beof advantage 'to form the completed sleeve 'hexagonal in .cross section with the conductor therein circular 'in cross section and sqiieezed by the sleeve sufficiently to reduce .the initial area of the conductor to a solid core of reduced cross section.

The invention in 'its method aspects features the dividing of the total operative length of the sleeve into ,areas sufliciently small in their length dimension so that each area `can be deformed separately, one lafter the other, by a small size crimping tool --of leither the 'manually .or

power-actuated type, `until fthe :desired 'length of 5engagement with the conductor .is had.

"ice

Accordingly, in the reinforced structure herein disclosed, with its hexagon sleeve in crimped engagement with the conductor, the upper, initial crotch portion of the sleeve is in the relatively soft condition in which it was originally cast, and the lower, initial leg-forming portion is work-hardened and compressed so that the lower half of the hexagon is harder than the upper portion of the hexagon and, despite the fact that it is a split tube, it adheres iixedly to the .conductor as if it were a solid tube.

Various other objects and advantages of the invention will be in part obvious from an inspection of the accompanying drawings and in part will be more fully set forth in the following particular description of one form of repair sleeve embodying the invention and of one method of forming the repair sleeve, and the invention also consists in certain new and novel features of construction and combination of parts hereinafter set forth and claimed.

In the drawings:

Fig. 1 is a View side elevation vof the stoel: repair sleeve with the central portion broken out and constituting ,a preferred embodiment of Athe article aspect of the invention;

Fig. 2 is a lview in .end elevation of .the showing in Fig. 1;

Fig. 3 is a view partly in side elevation and partly in Section in .the vertical medial longitudinal .plane of the assembly of sleeve and conductor, showing the stock sleeve of Figs. i :and 2 in position on a horizontally extending cable with the left portion in its initial unorirnped form as ,shown in Figs. :l and 2, with a pair of narrow crimping y.dies about to engage .the same, vand with .the righ-t .portion deformed into a .crimping engagement with the cable.' and Figs. 4 to 8, inclusive, are leach explanatory views `in cross section `of the sleeve as in iFig. 2, `showing -suceeeding portions lof :the dies and associated portions .of the sleeve, and wherein Fig. .4 is .taken on lthe line 4 4 of Fig. 13, and Fig. 8 is taken on ,the line 8-8 of Pig. 3.

In the drawing and referring iirst to the stock part or ,spl-it tube 10 shown in Figs. -1 and 2, there is .disclosed a one-piece .article .of manufacture constituting a casting formed .of malleable metal of channel structure and ,U- shaped in .all ,cross-,sections thereof. Ftlhe crotch portion 11 of the `channel structure is defined exteriorly by three upwardly-facing ilat faces marked '12, 13 and 14 Fig. 2, wit-h the .outer

inclined faces

12 and 14 forming an ang-le of 4sixty degrees, with rthe top `or middle face 13 to ,form texteriorly a half-hexagon. The `crotch Aportion of the channel is defined interiorly by a semi-cylindrical y surface-forming Aseat 15 for the cable to be repaired. it

' bisects .and vextends ynormal .to the face 13 as .hereinafter which is the line -of initial engagement with the lower powerfdie hereinafter described. rIihe sum of lthe lengths of the inner faces 19 of the legs is slightly greater than the yarc length of the cable seat 15 .and thus tare longer thanzthe-exposed under sidetof the .cable rvvhen in engagement with the `seat as hereinafter explained.

The metal forming the sleeve l@ is apportioned between the crotch and legs so that its center of mass is approximately at the center 16, so that when hanging on the cable the

legs

17 and 13 will depend perpendicularly from the crotch portion; the flat top face 13 will be horizontal; and the fiat side faces 12 and 14 will be more or less equally inclined to the vertical line of thrust [1 -b.

The stock article as thus far described is generally designated as a compression type cable repair sleeve, but actually it does not repair the cable; it supplements or bridges across and thus reinforces a damaged, worn or otherwise weakened portion of a cable. In the ease illustrated in Fig. 3, the sleeve is crimped about a portion of the stranded wire core A of an insulated cable B having an insulating jacket C and wherein one or more of the wire strands D are broken at the points E. ln the case illustrated the cable includes a steel core F its wire strands D are made of a soft grade aluminum. The sleeve 16 is made of the same metal as the strands D to provide about the same coefficient of expansion and to avoid any electrolytic reaction between the metals. However', it is within the scope of the disclosure to make the sleeve of copper or copper alloys when used with copper cables.

It is a feature of this disclosure that the crotch portion 11 be preformed with the accuracy which is possible in factory production to have the same configuration as is intended for the finished product when crimped onto the cable. This means that the upper portion of the sleeve within the outlines defined by the

faces

12, 13 and 14 of the sleeve when in use as shown in Fig. 8 is preformed and these faces are maintained substantially in their factory-formed relation. Also, as there is very little working of the crotch portion during the crimping operation it retains its initial unworked and relatively soft condition compared to the legs which become worked as they are wrapped inwardly about the cable and compressed by the squeeze action of the crimping dies.

The sleeve is intended to be installed on the cable either by a hand-operated crimping tool, in the case of small size sleeves, or by a power-actuated crimping machine, in the case of large size sleeves. In either case the crimping is had by means of a pair of coacting dies F and G whose work faces are provided with opposing recesses H which are of identical semi-hex configuration and disposed symmetrical with reference to the line of thrust a-b. It is the intent in the situation illustrated to deform the stock sleeve into a crimping engagement with the cable by successive crimping operations, in each case involving only a limited length of the cable and sleeve at any one time, and for this reason the dies F and G are shown in Fig. 3 to be relatively narrow compared to the area of sleeve to be crimped. The upper die F, referred to sometimes as the holding die, is relatively stationary after it has been lowered from its inoperative position to engage the

sides

12 and 14 of the sleeve. The lower die G, referred to sometimes as the forming die, is movable along the line a-b as indicated by the long arrow in Fig. 3. The sides of the recess H of the stationary holding die F, and particularly its inclined sides I and I, conform to the

preformed sides

12 and 14 of the stock article. The side K forming the bottom (actually the top) of the upper recess H is spaced slightly above the face 13 to form a clearance L therebetween. This is to compensate for any irregularities in the angular relation of the

preformed faces

12 and 14 and where lettering is present to avoid contact therewith. Similarly, the recess H of the lower die is defined by a pair of inclined side surfaces M and N and a connecting bottom surface P, and otherwise is identical with the opposing recess H of the upper die.

In one form of the invention the clearance L was reduced to the extent that it practically was non-existent but still the lettering was legible even though crushed.

In operation and having located the breaks E in the cable, the insulation jacket C is cut away as shown in Fig. 3 to expose the damaged part of the core A and that length of repair sleeve is cut ofi from stock sufficient to fill in the space between the adjacent ends of the insulation C remaining on the cable. rl/ith the dies out of thc way the sleeve 19 is then hung at any point desired onto the core A, overhanging the breaks therein and the cable is received in the seat 1S with the legs i7 and 18 dangling in space as shown in Fig. 4. The sleeve tends to locate itself rotatively on the cable with its side 13 more or less horizontally disposed by reason of the weight of the

pendulous legs

17 and 18.

The open sides of both of the die recesses H are slightly wider than the width of the sleeve and this means that with the sleeve centered by the upper die the sharp edges 22 dening the lower ends of the legs will come just within the recess H of the lower die as the lower die is elevated from the position shown in Fig. 4 into the position shown in Fig. 5. As the lower die bears upwardly on the

legs

17 and 15 the rst noticeable effect is that the

tlat sides

12 and 13 of the crotch portion are driven firmly against the downwardly-facing die sides l and .l and conform to the same and some of the clearance L may be taken up, but when lettering is present on the side 13 care is exercised to avoid mutilating the lettering. Thereafter the crotch portion 11 is retained immovable in the upper or holding die and presumably is not thereafter affected to any material extent by the squeeze action of the dies.

As the lower or forming die continues to move upwardly the free ends of the legs slide down the inclined sides M and N of the lower die recess and tend to curl inwardly towards each other as shown in Fig. 6, and along the bottom surface P. This action continues until the free ends of the legs contact mid-width of the surface P to form the split sleeve into an annular ring 23 with a closed joint 24 as shown in Fig. 7, with vacant spaces 25 formed on opposite sides of the joint 24 between the recessed part of the lower die and the under side of the sleeve. A lunar-shaped space 26 forms between the core A and the under side of the sleeve. Up to this point there has been no material change in the density of the metal forming the bottom of the ring 23 in Fig. 7.

As the dies reach their point of nearest approach or up to the point where they are in squeezed-together contact as shown in Fig. 8, the lower portion of the ring 23 is crowded in on itself to till up the spaces 2S and 26 and to give a half-hexagonal form to the lower portion of the sleeve until finally the resulting cross-sectional configuration is a complete hexagon in its exterior outline as shown in Fig. 8. As the legs are of equal length this action brings the closed joint 24 at the mid-width portion of the surface 29 forming the lower face of the completed hexagon. During the iinal stages of compressing the lower portion of the ring it bears onto the stranded core A; squeezes the same; the strands become compacted to their limit; and the individual strands lose their initial round character as indicated in Fig. 8.

Another action takes place between the Figs. 7 and 8 stages of the crimping operation. The legs become worked by reason of the bending and squeezing operation, which results in at least the lower portion of the sleeve as viewed in Fig. 8 becoming harder and more rigid than the factory-formed upper portion opposite the joint 24.

As soon as the crimp has been made the dies are separated conventionally and if necessary the crimped sleeve is knocked away from whichever die it may be adhering.

As soon as a crimping is so formed at one point, the dies are shifted to another point along the uncrimped portion of the sleeve as suggested in Fig. 3, and the operation repeated as often as is necessary. In the showing in 3 eight areas of crimps 27 haV e been made on the right side -of the showing, 'With the left side remaining intact -as .originally cast. As -the 'several ycrimps are formed narrow ridges 30 are formed, between succeeding crimps'by reason 1of Athe slight `spacing apart of the ycrimpmg dies lin their succeeding crimping acts. As shown -1n Fig. 3 the 4original diameter 'of the core ,A as it still exists exteriorly of the -right lend of the sleeve is of slightly greater diameter than the porti-on Whichhas been condensed by reason of Ithe several crimping operations herein featured.

It is suggested that the extreme right end of the sleeve have its legs infolded as above described -to 'form a closed ruig 29 encircling the uncompressed core, .but not compressed thereon, to provide a loose connection with the cable at the point where it emerges from .the repair sleeve. This tends to defeat possibility of the xrepair sleeve abraiding the core A.

It is suggested lthat the flat top surface 13 be utilized to contain Yembossed or upstanding let-tering 28 which can be formed integral with the stock sleeve sin the act of casting the same. This lettering ,may :comprise trademark designations, sizes and like display matters.

By means of a form of repair sleeve as herein :disclosed it is seen that all of the sleeve `of iFig. 8 .above the plane of contact between the dies ris in fthe exact cond-ition it was when originally cast and no deformation, or at least no material deformation, is imposed on this part of the sleeve during the installing of the same on the cable. All of the distorting effect has been localized on the thin and relatively easily bent legs. As the legs become compressed they lose their original soft character and become hard and rigid and thus tend to resist subsequent tendencies of the joint 24 to open.

As this joint faces downwardly this tends to avoid water creeping into the joint and in practice the inclined under sides of the hexagon form water drip surfaces.

l claim:

1. A one-piece casting formed of a soft malleable metal and possessing uniformly in all parts thereof the physical characteristics inherent in castings of such soft malleable metals, said casting forming a stock strip from which lengths may be cut as desired and the lengths thereafter mechanically formed into cable repair sleeves` of hexagonal cross section, said strip being cast in the form of a channel, U-shaped in all cross sections thereof and its crotch portion defined on its outer side by three substantially flat surfaces, with its two outer surfaces forming an angle of about sixty degrees with the flat surface therebetween to thus preform a first-named one-half of a hexagon as part of the casting, and said crotch portion defined on its inner side by a half cylinder and said casting including two legs extending integrally from the crotch portion in spaced-apart and in substantially parallel relation with their inner faces tangent to the half cylinder, and said legs being relatively thin, having a thickness less than that of the crotch portion and each capable of being bent when die-pressed mechanically towards the other to close the initial opening therebetween, and said legs collectively having a mass and volume capable when die-pressed to form a companion one-half hexagon to the first-named cast half hexagon.

2. An article of manufacture constituting a stock article from which a hexagonal compression type cable repair sleeve may be formed, said stock article being of one piece, formed of soft aluminum, 'U-shaped in cross section for its entire length and whose crotch portion defines externally one-half of a hexagon and adapted to t into the similarly shaped recess of a holding die and internally a semi-cylinder, and a pair of parallel and spaced-apart legs projecting integrally from opposite sides of the crotch portion, said legs being ductile with their free ends bendable under squeeze pressure inwardly towards each other to close the opening therebetween,

-6 Said .legs having a length -and ,aggregate mass .Sucient 'when crowded into ya suitable semi-hexagonal recess in a squeeze die and about a mandrel -of cylindrical 'form fitting vin the semi-cylinderinternally to complete the circle defined by the perimeter 'of the semi-cylinder and externally to complete the hexagon.

'3. An ,article of manufacture from which a ,cable repair ysleeve may 'Lbe formed in situ when hung on the cable, said varticle being an unworked casting formed from a malleable metal ,and including as part .of the casing a crotch-forming portion providing on its inner side a recess of semi-cylindrical form and on its outer side 'the three adjacent flat sides of a half-hexagon, and said casting including `two parallel and spaced-apart legs projecting integrally from the opposite sides ofthe crotch portion, said legs having less 'thickness of material .than the crotch ,portion and adapted -to be die-pressed about a cable -in ,the semi-cylindricalrecess as a mandrel to cause the legs lto wrap about the cable and also to 'form lthe legs `into a companion half hexagon thereby to 'form the repair sleeve as a complete 'hexagon -in cross section.

4. A repaired cable including a core-forming section of a cable, va one-piece 1split sleeve of malleable metal encircling the core -and at least in part permanently deformed into a crimping engagement with the core, and at its split 'forming a closed joint extending longitudinally ofthe sleeve, Said sleeve formed in effect of two integral 'half hexagons of similar size and configuration, one of the half hexagons being bisected by the closed joint, being worked and thus more rigid and harder than the other half hexagon, and said other half section being a casting made from said malleable metal and thus unworked and softer than the first-named half hexagon.

5. A one-piece split repair sleeve of malleable metal externally hexagonal in cross section and at its split forming a closed joint, said sleeve formed in effect of two integral half sections each defined by three adjacent at sides of a half-hexagon of which one half section contains the closed joint, the half section containing the closed joint being worked and thus stronger, more rigid and more compact than the other half section and said other half section being a casting having the density characterizing an unworked casting of said malleable metal and softer than the first-named half section.

6. In the art of securing a split tube constituting a channel-shaped casting of aluminum7 U-shaped in cross section, to a cable horizontally disposed and wherein the crotch portion of the tube is provided on its inner side with a semi-cylindrical seat for snugly receiving the cable, and said crotch portion outlined on its outer side by a preformed half-hexagon including two fiat outside faces disposed at about sixty degrees to the third flat face therebetween, and two legs extending integrally from the crotch portion, the method which consists in hanging the cast tube on the cable with its open side facing downwardly and with its legs depending below the cable, thereby to cause the tube rockably to assume a position with said third face at least substantially horizontal and with the legs depending vertically therefrom, and subjecting the tube to the squeeze action of a pair of superposed dies having opposing recesses each of half-hexagon form and wherein the dies have relative movement along a vertical line of thrust, the upper die being a holding die with downwardly-facing recesses of semi-hexagonal form and dimensioned to receive and hold the crotch portion without materially modifying it from its precast form, and the lower die being a forming die with its recess of semi-hexagonal form facing upwardly and dimensioned to receive the legs of the tube, causing the dies as they approach each other along said line of thrust to effect first an inward curling of the free ends of the legs about the cable until their free ends contact to form an annular ring with a downwardly-facing closed joint and finally as the jaws reach their point of nearest approach to cause the lower die to modify the lower portion of the ring so formed to cause it to assume a half-hexagon form coactingr with the initial upper crotchforming half-hexagon to provide a complete hexagon externally and internally to form a cylindrical form of bore crimped onto the conductor and to work the free end portions of the legs to form the lower portion of the ring containing the closed joint to make the same more rigid than the precast upper hexagon.

7. The method dened in claim 6 and wherein a continued approach of the dies after the complete hexagon is formed operates to squeeze the sleeve onto the conductor to increase the rigidity of the die-formed lower hexagon and thus tend to defeat subsequent opening of the closed joint without material affecting the initial cast condition of the upper crotch-forming hexagon.

8. ln the art of deforming a stock sleeve being a casting of malleable metal U-shaped in cross section, wherein its crotch is half-hexagon in exterior cross section and wherein a pair of parallel legs project integrally from the crotch, into a nished sleeve whose outer perimeter is completely hexagonal in cross section, by the use of a two-die press wherein each die is provided with a recess facing the other and each recess being half-hexagonal in cross section and wherein the dies when in abutting relation form a recess hexagonal in cross-seo tion, the method which consists in tting the half-hexagonal crotch of the stock sleeve snugly into the die recesses of one of the dies functioning as a holding die and with the legs projecting therefrom towards the other die, and then causing said other dies to approach the projecting legs, to receive the legs in the recess of said other die and as the dies approach their abutting position to cause the legs to curve inwardly towards each other and eventually to deform the legs into a form hexagonal in cross section, and thus to complete the formation of the sleeve hexagonal in cross-section.

References Cited in the le of this patent UNITED STATES PATENTS 556,649 Smith Mar. 19, 1896 650,862 McTighe June 5, 1900 1,727,895 Mraz Sept. 10, 1929 2,151,032 Jensen Mar. 2l, 1939 2,164,381 Bradley July 4, 1939 2,247,928 Temple July 1, 1941 2,327,651 Klein Aug. 24, 1943 2,554,813 Buchanan May 29, 1951 2,568,054 Clapp Sept. 18, 1951 2,572,956 Servis Oct. 30, 1951 2,617,845 Pierce Nov. 11, 1952 2,622,314 Bergan Dec. 23, 1952