US2536173A

US2536173A - Method of making conductor splices

Info

Publication number: US2536173A
Application number: US778237A
Authority: US
Inventors: James O Hamilton
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1947-10-06
Filing date: 1947-10-06
Publication date: 1951-01-02
Anticipated expiration: 1968-01-02

Description

Jan. 2, 1951 J. o. HAMILTON 2,536,173

METHOD OF MAKING CUNDUCTQR SPLICES Filed Oct. 6, 1947 i 2 Sheerls-Sheet 1 o N K an w E c N l-l II n 3 1 III X X X i I s INVENTOR J.O. HAMILTON ATTORNEV Jan. 2, 1951 J o HAMILTON 2,536,173

METHOD OF MAKING CONDUCTOR SPLICES Filed 00+ 3, 1947 2 Sheets-Sheet 2 J O. HAMILTON y A TTORNE pound.

Patented Jan. 2, 1951 METHOD OF MAKING CONDUCTOR SPLICES James 0. Hamilton, Dundalk, Md., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application October 6, 1947, Serial No. 778,237

2 Claims. (Cl. 154-222) This invention relates to methods of making conductor splices, and more particularly to methods of making flexible conductor splices.

In the manufacture of covered conductors, such as conductors having a plurality of insulated conductors therein and a jacket of weatherproof ing material enclosing the insulated conductors, it is often necessary to splice conductor lengths together. In order to accomplish this, the conductors of conductor lengths must be connected electrically, and, in some known methods of con necting the conductors of the conductor lengths, it is necessary to remove the insulation from the ends of theconductors, and to join the conductors by brazing, welding or other suitable methods. It is then necessary to insulate the bared portions of the conductors one from another with unvulcanized, vulcanizable insulating material, to vulcanize the insulating material on the bared portions of the conductors, to place a quantity of jacketing compound over the insulating material on the spliced portions of the conductors, and then to vulcanize the jacketing com- Such a series of molding operations keeps the cost of such splicing high, and, hitherto, there has been no successful method of molding the jacketing compound and the insulating compound in a single molding operation.

An object of the invention is to provide new and improved methods of making conductor splices.

A method illustrating certain features of the invention comprises enclosing a core of plastic material ina high tensile strength, high melting point sleeve, placing a mass of plastic material around the sleeve, and applying heat and pressure to the mass of plastic material to mold simultaneously it and the core.

A complete understanding of the invention may be obtained from the following detailed description of a method of making conductor splices forming a specific embodiment thereof, when read in conjunction with the appended drawing, in which:

Fig. 1 is a plan view of the ends of two conductor lengths to be spliced;

Fig. 2 is a fragmentary perspective view of a partially completed splice illustrating certain features of the invention;

Fig. 3 is an enlarged, sectional view of a completed splice;

Fig. 4 is an enlarged, vertical section taken along line 44 of Fig. 3, and

Fig. 5 is an enlarged, sectional view of the completed splice.

Referring now in detail to the drawing, a conductor length I0 to be spliced to a conductor length II consists of two conductors I2 and I3 enclosed and separated in a covering I4 composed of a vulcanized insulating compound, such as a compound including polymerized butadiene and styrene as its vulcanizable constituent, and a braid I5 of steel strands served in one direction and cotton strands served in a direction opposite thereto, encloses the covering of insulating material to provide mechanical strength and electrical protection for the conductor length. A weatherproofing jacket I6 encloses the braid I5 and is composed of a vulcanized jacketing compound, such as a compound including a polymerized chloroprene as its essential constituent. The conductor length I I is identical with the conductor length I0 and includes a pair of

conductors

22 and 23 which are separated one from another and are enclosed in a covering 24 composed of a vulcanized insulating compound. A mixed cotton and steel braid 25 encloses the covering 24, and a vulcanized jacket 26 encloses the braid 25.

In the splicing operation the end portions of the Jackets I6 and 26 are removed from the conductor lengths I0 and II, respectively. Portions of the braids I5 and 25 are removed from the coverings I4 and 24, respectively, and the coverings I4 and 24 are removed from the conductors I2 and I3, and 22 and 23, respectively, so that the conductors l2 and I3 may be brazed to the

conductors

22 and 23. respectively. The end portions of the braids l5 and 25 are lashed down tightly upon the coverings I4 and 24 by lashings 30 and 3I (Fig. 1), respectively. A braided sleeve 32 is slipped over the end of one of the cable lengths I0 and II, and the conductors I2 and I3 are brazed to the

conductors

22 and 23. A block 40 (Fig. 2) composed of either vulcanized or unvulcanized, vulcanizable insulating compound of substantially the same composition as the coverings I4 and 24 is positioned between the bared portions of the conductors I2, I3, 22 and 23 and extends from one end of the covering I4 to the near end of the covering 24. The block 40 is rectangular in cross-section. The depth of the block, which is the dimension of the crosssection of the block perpendicular to the plane in which the conductor I2, I3, 22 and 23 lie, is at least as great as that of the sum of the width of the block, which is the dimension of this crosssection in the plane of the conductors, and twice the diameter of the conductors. The length of ,strip 4| compresses the rectangular block and embeds the conductors l2, I3, 22 and 23 in the edges of the block 40 so that substantially no air is included therein. However, the block is sufficiently wide that the conductors |2 and 22 are spaced sufficiently far apart from the conductors l3 and 23 for insulating purposes. Furthermore, since the depth of the block is greater than the width thereof, the strip 4| tends to compress the block more in directions parallel to the depth thereof than in directions parallel to the width thereof. Hence, the internal pressure of the block keeps the conductors apart. A strip 42 composed of high tensile strength material, such as a strip formed of glass fibers, is wrapped under tension tightly around the strip 4|, and encloses this strip. The wrapped strip 42 forms a tube or container around the strip 4| and has a melting point 'sufliciently high to prevent it from melting or softening at the pressures and the temperatures of vulcanization.

The braided sleeve 32 then is positioned over the strip 42 so as to overlap the ends of the braids l5 and 25, and the braided sleeve is pulled taut so that it fits closely around the strip 42 and upon the braids l5 and 25. Lashing wires 45-45 then are applied to the sleeve 32, starting at the center of the sleeve and continued to the ends of the sleeve to lash it down tightly over the portions of the splice enclosed therein and to take out all the slack of the sleeve 32. The sleeve 32 acts as a mechanical barrier over the elements of the splice enclosed therein, and also serves to connect the braids l5 and 25 mechanically so that the elements of the splice enclosed within the sleeve 32 are protected from tensile forces applied to the conductor lengths. The sleeve also connects the steel wires in the braids electrically.

A covering composed of an unvulcanized, vulcanizable jacketing compound of substantially the same composition as that of the jackets l6 and 26 then is placed over the ends of the jackets and the portions of the conductor lengths i0 and H therebetween. The covering 50 and the portions of the conductor lengths enclosed therein then are placed between a pair of heated semielliptical mold sections and 62 which subject the splice therebetween to heat and pressure to mold the covering 50 into an elliptical shape and to vulcanize it, and to simultaneously form the block 40 and the sleeve 4| into the shape of an ellipse and to vulcanize this material. During the molding operation, the sleeve formed by the strip 42 does not melt or soften, and keeps the sleeve 4| and the block 40 from flattening out too much and from intermixing with the sleeve 50 of jacketing material, but permits transmission of heat and pressure to the sleeve 4| and the block 40 so that these elements are vulcanized.

The above-described method of splicing flexible conductor lengths serves to insure adequate spacing of conductors of the conductor lengths so that they are properly insulated one from another, forms an insulating covering around and between the conductors and a jacket around the insulating covering in a manner in which both the inlll) sulating covering and the Jacket may be molded and vulcanized in a single molding operation without losing the identity of either the insulatinsulating material and a jacket of weatherproofing material enclosing the insulating material, which comprises baring the end portions of the conductors of two such conductor lengths, connecting the ends of one pair 0f the conductors to the ends of the other pair of conductors, placing between the bare portions of the conductors a filler and spacer block of vulcanizable insulating material having a depth at least as great as the width of the block plus the diameters of the conductors, wrapping a strip of insulating material tightly around the bare portions of the conductor and the filler block therebetween, and applying heat to the resulting splice to vulcanize the insulating material and simultaneously exerting pressure on the splice in such a direction that the greatest pressure is exerted depthwise on the block, whereby the block tends to force the bared portions of the conductors apart.

2. The method of splicing conductor lengths or which each includes a pair of parallel conductors enclosed and separated from one another by insulating material and a jacket of weatherproofing material enclosing the insulating material, which comprises baring the end portions of the conductors of two such conductor lengths, brazing the ends of one pai of the conductors to the ends of the other pair of conductors, placing between the bare portions of the joined conductors a filler and spacer block of vulcanizable insulating material having a depth at least as great as the width of the block plus the diameters of the conductors, wrapping a strip of insulating material tightly around the bare portions of the conductor and the filler block therebetween, wrapping a tape of high tensile strength, glass fibers around the strip of insulating material, enclosing the tape with a mass of unvulcanized, vulcanizable jacketing compound, and simultaneously heating the composite structure to vulcanize the vulcanizable materials and applying.

pressure thereto in such a direction as to apply the greatest pressure on the block depthwise thereof, whereby the internal pressure on the block keeps the conductors separated.

JAMES O. HAMILTON.

REFERENCES crrEn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,698,704 Middleton et al Jan. 8, 1929 2,105,567 Webb Jan. 18, 1938 2,119,393 Lewis et al May 31, 1938 2,156,772 Seeley May 2, 1939 2,186,793 Wodtke Jan. 9, 1940 2,264,439 Guyatt Dec. 2, 1941 2,403,816 Martin July 9, 1946 2,435,284 Lodge Feb. .-2, 1948 FOREIGN PATENTS Number Country Date 421,073 Great Britain July 10, 1934 533,532 Great Britain Feb. 14, 1941 542,397 Great Britain Jan. 7, 1942