US2538225A

US2538225A - Method and means for joining coaxial cables

Info

Publication number: US2538225A
Application number: US638350A
Authority: US
Inventors: Edward L Alford
Original assignee: Bell Telephone Laboratories Inc
Current assignee: AT&T Corp
Priority date: 1945-12-29
Filing date: 1945-12-29
Publication date: 1951-01-16
Anticipated expiration: 1968-01-16

Description

E. L. ALFORD METHOD AND MEANS FOR JOINING COAXIAL CABLES Jan. 16; 1951 Filed Dec. 29, 1945 y Q fr. D N 1a. f E RM M m QN ww NQN SQNQ. mw @w E w QN mr, m NL WA L 1 1 111 N a 1 A. f 1 Q E n .Q Q\ ON \W QM D N\\ f Q \N DN 1 1 f l a, QQ R y U B X.

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Q 1 Q Q Q Q Q Q1Q1 Q1 Q QN QN Q Q S, QQ QN E. Q Q Q 1%. Q Q Q Q mw 11e Q NG WN WN QN www Q mw Q 1 i; 1 Q 1 .Q NN 1 Q 1 Q mw Q @N Q Q u 11 111 1 1 111 1 11 1 1 1 1 111 11 1, 1 H111 111111 11111m 1H! 11 1 11 1 1111 1 1 111 11 1111 11111 1111 11-1%11 1 1 111%1v11 111 11 11 1111 1-11 1w 1111111 11 111 1 11 Q mw Q 1 111.1 111 11\ n l Qw\ Q Q 1 Q Q 11 Q 91u ,on um QN uw Patented Jan. 16, 1951 UNITED STATES PATENT oFFlcE METHOD AND MEANSl FoR'JoINING ooAXrAL CABLES Edward L. Alford, Chatham, N. Je., assignor to Bell Telephone Laboratories,Incorporated, New York, N. Y., a corporation of New York Application December 2'9, 1945, Serial No. 638,350

4 Claims. 1

This invention relates to `joints or splices for electrical conductors and more particularly to a method of making joints in conductors of the coaxial type, one or more of which may be enclosed in a suitable protective sheath to form a cable.

The object of this invention is the provision of a method and means for splicing coaxial conductors which will eliminate, to a large extent, the introduction of fine metallic particles into the joint during the making of the joint as has been experienced with the method now employed, and the consequent short-circuiting of the conductors in the cable.

Another object of the invention is theprovision of method and means for making joints in coaxial rconductors which will require considerably less pressure on the component parts to form a gastight and an electrical joint having a high conductivity.

The coaxial conductor to which the spliceof this invention is particularly adaptable comprises, a tubular outer conductor of relatively thin conducting material and a centrally disposed solid inner conductor which is supported concentrically within the outer conductor and insulated therefrom by means of a plurality of suitably spaced discs or bushings of insulating material. In order to provide electromagnetic shielding for the conductors, a plurality of metallic tapes are helically Wound around the outer or tubular conductor. One or more conductors may be enclosed in a lead sheath to form a suitable cable.

Cables employing one or more encased coaxial conductors are known as coaxial cables amd are employed for transmitting electrical currents of very high frequency and it is important that the joints in the conductors be made in such a manner that the eiiiciency of the cable will not be impaired. ,l

The present invention relates to a method and means for making joints in coaxial conductors of the above-described type and comprises, inserting in the ends of the outer conductors, in contact with the inner surfaces thereof, short metallic reenforcing sleeves, positioning on the outside of each outer conductor over the metallic tapes and adjacent the vends thereof a short metal sleeve, positioning over one end of the conductor and underlying the metallic tapes, a third metallic sleeve having a length somewhat longer than the other two sleeves, joining together the central solid conductors by means of a suitable sleeve,

locating the large sleeve over the joint of the inner conductors with its endsl overlying a substantial portion of the outer conductor and the reenforcing sleeve, positioning the small sleeves in abutting relation With the large sleeve and then` tact with the steel tapes, to provide a gas-tight joint having substantially the same electrical characteristics" as these of the conductors.

The inventionwill be more clearly understood from the following detailed description when read in connection with the following drawings of which:

Fig. l is a fragmentary view, partly in section of the jointpof this invention in its early stage of preparation', with the central conductors joined together, the reenforcing sleeves in place, the tapes held in position by the rings and the small outside sleeves in place over the ends of the outer conductor and the tapes;

Fig. 2 is a view similar to Fig. 1 except that the tapes are now in position around the outer conductors and the sleeves have been moved in position with the large sleeve over the joint of the inner conductors and the small sleeves over the ends of the tapes;

Fig. Y3 is a view similar to Fig. 2 and discloses suitable means for forcing the sleeves into intimate Contact with the outer conductors and metallic tapes to provide a completed joint; and,

Fig. 4 is a cross-sectional view taken on line 4-4 of Fig. 3 and illustrates in detail the crimp- Y ing ring for holding the metallic tape in position While making the joint.

As shown in the drawing, the joint of this inventionl comprises three sleeves, namely, a large central sleeve I0 and the two small end sleeves I I and I2. The central sleeve I0 is centrally disposed over the sleeve I3, which serves to join the ends I4 and I5 of the central conductors I6`I6 together, and embraces the outer surfaces of the ends*V I1 and I8 of the outer conductors Ill-I9 for a. short distance on each end. The small end `sleeves II and I2 are positioned over the ends of the metallic tapes 20 and 2|, the sleeve II engaging the

ends

22 and 23 andthe sleeve I2 engaging the ends 24 and25.

Located in the conductors |6-I6, a short distance from each end thereof, are the reenforcng sleeves 2S and 21. Suitable insulating discs or spacers 23 maintain the solid conductors |6-I6 centrally disposed within the outer conductors I9`-I9.

In making the joint of this invention, the lead sheath (not shown), which encloses the conductors to be joined, is removed some distance from the ends thereof in the well-known manner, to expose the coaxial conductors located therein. The ends of the conductors to be joined are pre* pared in the following manner. A suitable ring 29 is threaded over the outside of the metallic tapes 2D and 2| of the conductor to the left of the splice and crimped thereover some distance from the end thereof. The next step is to remove a portion of the metallic `tapes 2U 2| at the end of the conductor to expose a portion of the outer conductor I9, asshown he,draw ing, then proceed to cut and remove 'a ,Smll section of the outer conductor I9 leaving exposed, however, beyond the tapes and 2| and end portion Il. The removal of a portion of the outer conductor I9, exposes the solid inner conductor I6 and its associated spacer 28 which is also removed. A portion of the conductor I6 is out off so that it projects only a short distance beyond the end of the outer conductor I9. Thus .we have the solid or central conductor I6 projecting a short distance beyond Vthe end of the outer conductor ,I 9 and the outer conductor .I 9 projecting a short `distance beyond the end of the metallic .tapes 2 9 and 2|. After the above steps have been completed, a reenforcing sleeve or bushing 26 is inserted in the outer conductor I9, a short distance beyond the end Il thereof and an insulating spacer 2.8 is positioned in the end ofthe outer conductor I9 with its outer face flush with the end ITI of the outer conductor I9.

With the metallic tapes 2G and 2i held in tig-ht `Contact around the outer conductor I9 by any suitable means, a small sleeve I I is threaded .thereover and positioned some distance back from 4the end .I'I of the outer vconductor i9 ywhich may be against the ring 29 as shown in Fig. 1. A large sleeve Il! is positioned over the outer conductor I9 and slid under the tapes 29 and 2l a sufcient distance so that the end thereof is `slightly in back of A4the end Il of the conductor [.9 as shown in Fig. 1.

The end I8 ,of the right-hand conductor which is to be joined with the left-hand section, here tofore described, is prepared ina similar manner except that the tapes 20 and 2 I are not loosened but are held in place by `means of clamping rings 39e-3.9 and no large sleeve is positioned thereon.

With the ends of the .conductors to be joined prepared as heretofore described and with the ends .I'l and .I8 of the Aouter conductors I9.- I9 in alignment and with the ends I4 and'IS of the inner conductors I6-II3 .directly opposite each `other and spaced apart slightly, a metallic splicing sleeve I3 is positioned over the ends thereof and ,compressed thereon, as shown at 3I.-e-3l in the various vfigures, to join the ends I4 and I5 of the central conductors I-IG together, an in sulating disc 28' is positioned over the sleeve I3 at its midpoint.

With the joint prepared as sho-wn in Fig, 1 and as described above, it is now ready for closure and as shown in Fig. 2 this is accomplished by sliding the sleeve ID over the vouter conductors IB-.I-Q so as to cover the splice and bear against the temporary spacer 33 which in turn is positioned against the small sleeve I2, making sure that the tapes 2U and 2! on the left-hand conductor end are tightly wound around the outer conductor I9. The small sleeve II is slid along its length until it bears against the .end of the sleeve IIJ as shown in Fig. 2. With the sleeves IIJ, II and I2 in position as shown in Fig. 2, a length of adhesive tape 33 is Wound around the tapes 20 and 2| adjacent the sleeve II to prevent movement thereof.

As shown in Fig. 2, the joint is now in condition for the final operation which is forcing the sleeves JIU., II 4and I2 in-to intimate contact with the tapes 'and o uter conductors to `form a gastight joint having a high conductivity. It has been found that the rolling tool shown in Patent 1,896,512 toHayford et al. dated February 7, 1933 is particularly adapted for use with this type of joint since it is not cumbersome to handle and can .be operated :with a minimum amount of torque.

The vfirst step in rolling the sleeves I0, II and I2 into `intimate engagement with the tapes 20 and 2| and the ends II and I8 of the outer conductors I9.-4S, is to position the rolling tool 34 to the left of the sleeve II with the

ats

35 and 36 of the rollers STI and 38 parallel. The conductors and sleeves are 4,then positioned in the grooves 39 and 4;0 Of the rollers 31 and 38 and the handle `4I iotated ,in a .clockwise direction to ycause the vrefilers 3,9 and 3l to traverse the lsleeves as shown in Fig. 3 and compress the sleeves I9, II and I2. ine vtemperary spacer ,3,3 may be rremoved any .time a'fitger the rolling action oj the [central sleeve jfil begins ,a5 it only serves to provide -suiiicient space e2: '.fQr .the sleeve I9 lto expand.

'.he :tool 34 is removed-:from the cable by .rotating the vrollers 3'! and 38 until the fla-ts 36 are Vagain parallel.

While I have shown and described jherein the preferred embodiment of my invention, it :is t0 be understood that various modifi-,cations and changes may be made therein without departing from thespiri-t ofthe invention `and YI do not limit myself to the use of .any particular tool for forcmetallic sleeve positioned .over the inner conducjoining means in engagement with the outer surfaces of the outer conductors and extending over said reenforcing bushings, metallic sleeves located one at each end of said first sleeve over said protective sheath, all of said sleeves secured in position by having a force applied thereto along the outside surfaces thereof to establish an Y2. In combination with a pair oi coaxial conductors each comprising a plurality of outer protective metallic tapes, an outer conductor `andV an inner conductor., of means for joining the -ends of said -conductors together which comprises, means-for joining the ends of the inner conductors together, metallic reenforcing bushings vlocated inside the outer conductors, a metallic sleeve positioned over the inner conductor joining means in engagement with the outer surfaces oi the outer conductors and extending over said reeniorcing bushings, metallic sleeves located one at each end of said first sleeve in 5 contact with said metallic tapes, all. of said sleeves secured in position by having a force applied thereto along the outside surfaces thereof to establish an intimate contact between said first sleeve and the outer-,conductors, and between said end sleeves and said metallic tapes,

3. In combination with a pair of coaxial conductors, each comprising an outer protective metallic sheath, a single hollow outer conductor and a solid inner conductor, of means forX joining the ends of said conductors together which comprises, means for joining the ends of the inner conductors together, metallic reenforcing bushings located inside the outer conductors, a metallic sleeve positioned over the inner conductor joining means and in engagement with the outer surfaces of the outer conductors and extending over said reenforcing bushings, metallic sleeves located one at each end of said rst sleeve in contact with said metallic sheath, all of said sleeves secured in position by having a force applied thereto along the outside surfaces thereof to establish an intimate contact between said first sleeve and the outer conductors, and between said end sleeves and said metallic sheath.

4. A method for making a joint in coaxial conductors having a solid central conductor, a hollow outer conductor and a layer of tape armoring over said outer conductor which comprises, removing from the ends of the conductors sufficient tape armoring to expose the outer conductor, removing a portion of the outer conductor to expose the inner conductor, inserting in the ends of the outer conductor in contact with the inner 6 l surfaces thereof, short metallic reenforcing bushings, positioning over the tape armoring adjacent the ends of said outer conductor sleeve members, positioning over one end of the outer conductor and underlying the armoring tapes, a third metallicsleeve, joining together the ends of the central conductor, locating the third sleeve over the joint of the inner conductor with its ends overlying a substantial portion of the outer conductor and said reenforcing bushings, positioning the end sleeves in abutting relationship with the ends of the third sleeve and then subjecting the whole assembly to the compressing action of a suitable tool for forcing the third sleeve into intimate contact with the outer surfaces of the outer conductor and the end sleeves into intimate contact with the armoring tape.

EDWARD L. ALFORD.

REFERENCES CITED The following references are of record in the le of this patent: v

UNITED STATES PATENTS Number Name Date 1,735,563 Deckard 1- Nov. 12, 1929 2,111,651 Wentz Mar. 22, 1938 2,133,448 Harley Oct. 18, 1938 2,210,804 Eby Aug. 6, 1940 2,305,473 Hayford Dec. 15, 1942 FOREIGN PATENTS Number Country Date 465,417 Germany Sept. 8, 1928