US2269877A - Electric conductor - Google Patents

Description

Jan. 13, 1942-` G. A. JOHNSON ELECTRIC CONDUCTOR Filed April 9,

A INVENTOR @414m A ORNEYS* Patented Jan. 13, 1942 AApplication April 9, 1940, Serial No. 328,601 l 9 Claims.

This invention is directed to the provision of a new and novel construction in insulated conductors.

Under present practice in some types of insulated conductor it is customary to braid cotton threads about the conductor insulation, or to wrap one or more cotton threads helically about the insulation. Itis customary also to braid cotton threads about an assembly of two or more conductors, the cotton braid being applied directly about the insulatedv conductors and/or the assembly of conductors. It is quite usual also to wrap paper tape helically about an insulated conductorassembly after which cotton threads are braided about the whole assembly.`

The present invention entirely eliminates the use ofv braid and the braiding operation, the same protection, however, being afforded the insulated conductor.

By eliminating the braiding operation I effect great economies fin machinery and floor space.

The elimination of the use of braid also provides for a very large increase in output in that by my invention the insulated conductor can be covered at the rate of as high as 500 feet per minute as compared with 180 feet per hourl or but 3 feet per minute which is about maximum braid` ing speed.

Morespecillcally the present invention -provides iorv the application of a prewoven fabric to the insulated conductor, the fabric being of such a nature that .the flexibility of the conductor is retained, a conductor constructed in accordance with my invention being as flexible as when braided coveringl is employed.

In its broadest aspects my invention comprehends the application to a conductor assembly, such as an insulated conductonor a plurality of insulated conductors, armored cable,'etc., of a prewoven fabric folded or wrapped in the direction of its length about the conductor assembly.

More speciiically my invention 'coniprehends the application to theinsulated conductor in continuous lengths of a`c1oth tape folded or wrapped in the direction `oi its length about the conductor, the threads of the tape extending diagonally of the conductor axis; or, to state it in other fashion, vthe warp and woof threads extending respectively to the right and to the left with respect to the axis of the conductor. To obtain thisvspecific effect, the tape may be cut on the bias, or, as a` possible alternative, the tape may be cut\straight instead of on the bias,

wrapped in the direction insulated conductdr, and the assembly given a slight'twist to shift the threads of the wovenfabric with respect to each other so that the warp and Woof threads no longer cross each other at right angles as theydo in the fabric as it is originally woven. v

It will be appreciated that where the fabric is not cut on the bias nor the assembly twisted, the conductor assembly is suiiiciently flexible for many purposes and of course the mechanical protection afforded `by the fabric is as good as the braid. However, when great flexibility is desired then I prefer to have the fabric so disposed that the warp and woof threads extend y diagonally of the longitudinal axis of the conductor.

With the threads of the fabric extending diagonally of the conductor axis, the threads simply slip on eachother when the conductor is bent so that the flexibility of the conductor is not impaired at all. t

l It is to be understood that the weave employed in the fabric may be varied over a wide range.

This has reference to the size of the thread employed as well as to the number of picks to the inch. It is quite evident that with one class of work it might be desirable to employ a coarse weave while a much nner weave would-be'satisfactory under other conditions.,

,z It is to be understood also that my invention comprehends the use of the prewoven fabric wherever braid is now used, and that flameretarding and moisture-resisting saturants can be employed aswell as with therbraided stock.

lIt will be appreciated that it is impracticable and unnecessary to illustrate the application of my invention to insulated conductors of every conceivable design, and I have -therefore only illustrated embodiments of the invention with respect to two constructions.

Fig. 1 illustrates an insulated .conductor in which the fabric is applied directly about the -conductor insulation;

of its length about the tion to a multi-conductor cable.

Referring first of all to Figs. 1, 2 and 3: A

flexible conductor 2 is shown insulated with insulation 4'. This insulation may be rubber composition or other rubber-like material, or, for

that matter, any flexible insulation desired, it 5 being understood that the advantages of my invention will be realized irrespective of the type of insulation 4 employed.

In the practice of my invention, with respect to Figs. 1, 2 and 3, a prewoven fabric tape 8 is 10 bent or `wrapped in the direction of its length about the conductor insulation 4. Its adjacent edges! and Il may be overlapped as illustrated in Fig. l or may be simply butted as in Fig. 1^.

As above pointed out, the tape need not be cut f5 on the bias but may simply be folded or wrapped in the direction of its length about the insulation without detrimentally impairing the exibility of the conductor assembly. However, where maximum flexibility is desired then the warp and which theyhave shifted due to bending or flexing the conductor. i

The diagonal disposition of the threads I2 with respect to the conductoraxis is most easily obtained by ycutting the prewoven fabric on the bias. On the other hand, a comparable effect is obtained by cutting the prewoven fabric straight and giving a slight twist to the conductor assembly after the application of the fabric to the conductor insulation.

The application of the prewoven fabric to the conductor insulation is a simple matter and may be effected in any desired manner. For example, the insulated conductor and the tape may be run through a tubing shoe which folds or 'wraps the tape in the direction of its length about the con-vx ductor insulation. The prewoven fabric tape mayy be' applied either before or after the insulation has been vulcanized, assuming for the sake of discussion that the insulation 4 is vulcanizable.

In fact, the application of the prewoven fabric tape may immediately follow the operation of applying the insulation to the conductor so that the whole operation may be a continuous one. Any suitable cement or other adhesive may be employed at the edges 8 and I0 of the tape. 'Ihe 55 fabric may be cemented or otherwiseadhesively secured to the insulation 4 throughout the entire area of the fabric should this be desirable or required. I have already pointed out that the adjacent edges B and I0 of the fabric tape are not 60 necessarily overlapped but may simply be butted if desired.

In Fig. 4 I have illustrated another embodiment y of `,the invention. In this illustration I show two conductors 2 each covered with insulation 4 with 65 prewoven fabric 6 folded or wrapped` in the direction of its length about this insulation. In other words, in this illustration each insulated conductor construction is a duplicate of that shown in Fig. l. conductors are wrapped spirally with paper I4, this assembly being enclosed in prewoven fabric tape I8. 'Ihis tape may be the same as the tape l, but, in any event, it is folded or wrapped in the direction of its 1engtn about the paper 75 The insulated and fabric-covered wrapped conductor assembly, and the warp and woof threads thereof are shown extending diagonally with respect to the longitudinal axis of the assembly, the same as explained in connection with Fig. 1. About the prewoven fabric I6 is another paper Wrap I8, preferably wound oppositely to the paper wrap I4. This assembly is steel armored by armoring 20. Finally a prewoven fabric tape 22 is folded or Wrapped in the direction of its length about the armor 20 with the threads' of the fabric extending diagonally of the longitudinal axis of the assembly.

It will be appreciated that in some instances the armor 20 may not be necessary, in which event the fabric 22 is applied directly to the paper I8.

It will be understood that in all embodiments of my invention the prewoven fabric may be treated with any saturant desired, such as flameproofing or flame-retarding saturant, moistureresistant saturant, etc., common in this industry.

It will be clear from the foregoing that my construction is a very decided advance in this art in the elimination of the necessity for braiding without sacriceof the protection afforded bya braided covering. As pointed out at the first part of this description, my invention eiIects enormous economies in that it eliminates the braiding machines with their attendant expense, and enormously increases production, a possible 500 feet per minute as compared with about 3 feet per minute maximum speed of braiding machines.

I wish it to be understood that changes may be made in the details of construction and arrangement of parts herein described and illustrated without departing from the spirit and scope of my invention.

What I claim is:

1. A n article of manufacture comprising an insulated electric conductor the insulation of which is covered with a prewoven fabric tape extending continuously lengthwise of the conductor, the fabric tape being folded longitudinally about the conductor insulation, to bring its opposed longitudinal edges together along the longitudinal axis of vthe conductor, thereby completely surrounding the insulated conductor, the threads of the prewoven fabric tape extending diagonally of the longitudinal axis of the conductor. A

-2. An article of manufacture comprising in combination, an insulated electric conductor, the insulation of which is covered,` with a prewoven fabric tape folded longitudinally about the conductor insulation, to bring its opposed longitudinal edges into engaged relation along the longitudinal axis of the conductor, the tape being cut on the bias whereby when it is placed about the conductor insulation its `warp and Woof threads will extend diagonally to the longitudinal axisof the conductor.

3. An article of manufacture comprising in combination, an insulated electric conductor the insulation of which is covered with a prewoven fabric tape, adhesively secured to the conductor insulation, the tape being folded longitudinally about the conductor insulation to bring its opposed longitudinal edges into engaged relation along the longitudinal axis of the conductor, the warp and Woof threads of the tape extending diagonally of the longitudinal axis of the conductor.

4. An electric cable comprising one or more insulated electric conductors the insulation of which is enveloped in a prewoven fabric tape folded longitudinally about-the conductorl insulation to bring its opposed longitudinal edges into engaged relation along the longitudinal axis of the cable, the threads of the tape extending diagonally of the longitudinal laxis of the cable. 5. An armored electric cable with a strip of prewoven fabric tape folded longitudinally about thecable armor to bring the opposed longitudinal edges of the tape into engaged relation along the longitudinal axis of the conductor, the threads has a prewoven fabric -tape folded longitudinally I longitudinal axis of the cable.'

,of the tape extendingl diagonally toA the longitudinal axis of the cable. 6. An electric cable, each conductor of which about its insulation with the ythreadsI of the fabric extending diagonally of the conductor axis, and a prewoven fabric tape covering common to the cable conductors, the last-mentioned cover--l ing being folded longitudinally about the covered insulation of the vconductors to bringits opposed edges into engaged relation along the longitudinal axis of the cable, the threads of the last mentioned tapeextending diagonally of the lon-y '7. An electric cable comprising in combination, a plurality of insulated conductors, a prewoven fabric tape folded longitudinally about the insulation of each conductor to bring the. opposedlongitudinal edges of .each tape together along the longitudinal axis of each conductor, a spiral wrappingl of fibrous material about the covered conductora-and a prewoven fabric tape covering about said spiral wrapping, said lastmentioned 8. Anelectric cable comprising one or more insulated metallicelectric conductors, a spiral wrapping of fibrous material about the conductor insulation, a prewoven fabric tape folded longitudinally about the fibrous wrap to bring the opposed longitudinal edges of the tape into engaged relation along the longitudinal axis of the cable, a spiral wrapping of fibrous material about saidprewoven fabric and aprewoven fabric-tape covering folded longitudinally about the last mentioned 'fibrous wrap to bring'the opposed longitudinal -edges of the lastmentioned tape into iengaged relation along the longitudinal axis of thel cable, the threads of each of said fabric tapes extending diagonally of the longitudinal axis of the cable. .f

, 9. An article of manufacture comprising an insulated electric conductor, the insulation of which isl covered with a prewoven fabric tape extending continuously lengthwise of the conductor, the fabric tape being folded longitudinally about the conductor insulation until its opposed longitudinal marginal portions are brought into engaged relation, thereby completely to surround the/conductorcinsulation. the threads of the prewoven fabric. tape"extending diagonally of the longitudinal axis of the conductor.

GUSTAVE A. JOHNSON.

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