US1586811A - Method of covering cores - Google Patents

Description

June 1 ,1926. 1,586,811

A. R. KEMP METHOD OF COVERING CORES Filed April 30, 1925 Patented June 1, 1926. i

UNITED STATES PATENT OFFICE.

ARCHIE R. KEMP, F TOWACO, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRIC COM- PANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

METHOD OF COVERING CORES.

Application filed April 30, 1923. Serial No. 635,542.

This invention .relates to methods of c0vering cores and more particularly to the covering of cores with vulcanizable plastic material.

When two lengths of a core, such as an electric conductor which is insulated with a vulcanized sheathing, are spliced together to provide a mechanically and electrically continuous core, it is necessary that the splice be provided with an insulating covering comparable with that over the remainder of the core. Also it is sometimes necessary to cover a portion of such a core which may become exposed, due to the removal of the associated vulcanized sheathing, with a similar covering. Since in such cases the covering must be vulcanized to agree with and to unite with the insulation of the remainder of the core, it is desirable that the covering be readily adhesive and be of such a character that it may be vulcanized within a short period without deleteriously afiecting the previously vulcanized sheathing ad acent" thereto.

An object of this invention is to cover a core with plastic material.

A further object is to expel air from the surface of the core while covering it with a plastic coating. Another object is to cover a core with a non-porous vulcanized coating. An additional object is to cover an exposed portion of a sheathed core, such as that occurring at a splice therein, with a coating homogeneously united with and having characteristics similar'to the vulcanized coating on the remainder of the core.

It is believed that the invention will be clearly understood from the following description and the accompan ing drawings relating to one embodiment o theapparatus by means of which the process may he practiced.

' In the drawings,

Fig. 1 shows an end elevation of a preferred form of vulcanizing apparatus particularly adapted to be used in connection with the vulcanizing of material covering a splice in a core, or an exposed portion of a core;

Fig. 2 is a fragmentary view, in section, of such apparatus containing a spliced core and the assoc ated portions of covering material prior to the operation of the apparatus. Fig. 3 is a similar view, showing the condition existing while the covering is being vulcanized;

Fig. 4 shows an end-wise sectional view.

along the linesA-i of Fig.2, and

Figs. 5 t0 8 inclusive show successive stages in the-application of a preliminary coating to one particular type of core to which the invention is especially adapted.

Referring to the drawings, a base 10 supports a fixed lower mold portion 11 adapted to co-operate with a movable upper mold portion 12, the latter portion being movable toward or away from the former portion by means of a suitable operating rod 13 suitably mounted in a projecting lug of a sleeve -or lowers the member 17 along the post 15 and the upper mold portion 12 mounted therein is moved toward or away from the lower portion 11, dependent upon the direction of rotation of the sleeve.

The mold portions 11 and 12 are provided with centrally located substantially semicircular depressions 18 and'19, extending throughout their length for receiving cylindrical portions 21 and 22 respectively of plastic material to be used in covering the exposed portion of the core. Near the ends of the depressions annular flanges 23 and 24, the edges of which when the two mold portions are in their closedposition, leave an opening having the same diameter as the sheathed core. These annular projections prevent the free extrusion of the plastic material out of the ends of the mold, over the surface of the sheathed core. Lengthwise channels 25 are provided on either side of the depressions 18 and 19 for receiving the surplus plastic material as the upper mold portion is advanced to its closed position. Each of the mold portions 11 and 12 is provided with some suitable heating means, such as an electrical resistance unit which may be connected with any suitable source of current by pairs of conductors 40 and 41 respectively so that the temperatures of the portions may be selectively controlled.

Referring particularly to Figs. 5 to 8 inclusive a metallic core 30 is shown which may be composed of a large electrical conductor surrounded b a plurality of smaller conductors and to wl i 3.1 of adhesive material may be applied to the cores prior to the application thereto of the plastic joining material.

Although it is to be understood that the invention is not to be limited in any manner thereby, the process will be described in detail as being employed in connection with.

the covering of, a splice in an insulated electrical conductor of the general type disclosed in the co-pending application of Robert R. Williams, Serial No. 674,161, filed November 12, 1923, to which the process and the apparatus disclosed is particularly adapted.

In the manufacture of such an insulated conductor, a thin layer of substantially pure gum rubber is formed around the composite conductor and plastic vulcanizable material, which may be of the type disclosed and claimed in the co-pending application of A. R. Kemp, Serial No. 521,032, filed December 8, 1921, is then formed over the rubber and the core sheathing is vulcanized in any suitable manner. When it is desired to cover a spline in, or an otherwise exposed portion of, such a conductor, it is necessary to employ a material which may be quickly applied, which closely adheres to the core and the adjacent covering prior to its vulcanization, which may be quickly vulcanized and thereby thorou hly united with the previously vulcanize covering of the core adjacent the exposed portion without producing any deleterious effects and furthermore which provides a covering possessing substantially the same characteristics as that over the remainder of the core length.

A material of this type which possesses all of these characteristics is disclosed and claimed in the co-pending application of A. R. Kemp Serial No. 673,822, filed November 9, 1923, and consists essentially of the following ingredients and in the proportions named:

Per cent. Rubber (3) 40 Zinc oxide 35 Iiitharge 20 Sulphur 4 Parafline 1 having a width in excess of the circuinten ence of the spliced core is placed in a horiich a plastic sheathing.

"extruded over the core.

zontal position underneath and in tangential contact with the core 30 as shown in Fig; 5. Care is taken to insure that the line of contact along the underside of the core is continuous, after which the portions of the sheet Tm on either side of such line-of contact are pressed upwardly against the circumference of the core, gradually working around the core in the successive positions shown in Figs. 6 and 7. In this manner all air is expelled from the surface of the metallic core preceding the contact of a portion of the sheet with the corresponding portion of the core. lVhen thesheet assumes the position shown in Fig. 7 the core is completely encased with a rubber film in very much the same manner as it would be if rubber were The excess sheet is then cut away and the ends folded down as shown in Fig. 8.

The cylindrical portion 21 of the jointing compound is then prepared by cutting away a portion of each end of the cylinder so that the ends conform to the tapered portions of the vulcanized material adjacent the spliced portion of the core. The lower mold portion 11 is then heated slightly and the cylinder of compound is placed in the depression 18, care being taken to insure that intimate contact is made between the surfaces of the depression and the jointing compound. The upper mold portion 12 is then lowered to its closed position over the lower portion 11 and both mold portions are heated for three or four minutes to a temperature between 200 and 220 F.', this rendering the cylinder 21 more adhesive and sufficiently plastic that it will flow readily upon the application of pressure thereto. In the meantime the portion 22 is similarly prepared and heated, externally of the mold, by a gas flame or by some other suitable means. Also the tapered ends of the vulcanized covering over the core adjacent the splices have been rubbed with some of the plastic jointing compound to remove any'loose particles of the vulcanized sheathing as well as to fill the cavities or depressions in the tapered surfaces with the compound. The upper portion of the mold 12 is then raised and the spliced core is placed longitudinally above and in tangential contact with the portion 21'. The heated portion 22 of jointing compound is similarly placed on top of the core. In each case contact is first established between the mid points of the cylinder of jointing compound and of the exposed surface of the core, and the line of contact is then extended in each direction until it'reaches the end of the two to three minutes. Due to the tangential line of contact between the cylinders of comtapered vulcanized coating in each direction 4 around the circumference of and expelling all air from the core surface. When the approaching"films" of 'jointing compound meet, the core is thoroughly surrounded by the jointing compound without any inter-' vening air. As the mold 'portion'lfl descends further the excess compound is forced outwardly into the channels 25 and from thence it may extrude. at the end of the mold. The temperature ofthe molds is then increased to approximately 300 and retained at such. a temperature for a period of approximately twenty minutes. Thereafter the upper portion 12 is raised and the core and theassociated splice is removed from the apparatus, after which'the sheathing is rapidly cooled by sponging with cold water.

By the. complete expulsion of air from the core before the application of-the jointing compound there is no tendency to intro duce bubbles into the compound during vulcanization and as a result a substantially non-porous sheathing is obtained.

It willbe evident that the process may be employed in continuously covering a moving core in which case the continuous'cyhnders of vulcanizableinaterial may be ex truded adjacent and parallel to the moving core or applied thereto in some other manner and the core with the associated cylinders passed through. suitable molds adapted. to spreadithe material over the surface of the core and to thereafter vulcanize such material.

What is claimed is:

'1. The method of extending a vulcanized sheathing over a core which consists in placing a batch of plastic material in tangential. contact with the core and the sheathing and completely spreading the material from -such' contact over and expelling air from the surface of the core. t

2. Thev method of extending a vulcanized sheathing overa oore which consistsein placing a plurality of separated batches of such material in tangential contact with the core and the sheathing, and applying pressure to the batches to cause the material thereof to spread completely over and exclude air from the surface of the core.

3. The method of extending a vulcanized sheathing over a core which comprises applying. plastic material laterally to the core and the sheathing, spreading the material sidewise over the core so as to expel air from the surface of the core, and subsequently vulcanizing the material.

4. The method of extending a vulcanized sheathing over a core, which consists in placing a plurality ofseparated rods of plastic I material in tangential contact with the core and the sheathing, and applying pressure to the -ortidns, causing the material thereof to completely cover the core.

I). The method of covering a core with plastic material, which consists in placing a plurality of separated cylindrical portions of such material in tangential contact with the core, and applying pressure to the cylindrical portions at points diametrically opposite to the line of contact between the cylinders and the core, causing the plastic material to flow equally from each contact line around the core and expelling all atmosphere from the core surface between the" approaching walls of plastic material.

6. The method of extending a vulcanized sheathing over a core which comprises ap-- plying plastic material to one sideof the core, heating the material to. increase its plasticity, applying pressure to the warmed material tocause it to flow toward the op posite side of the core, and subsequently vulcanizing the material.

7 The method of covering a core, which consists in placing a plurality of separated batches of vulcaniz'able material in tangential contact with the core, simultaneously applying pressure to the batches to cause the material thereof to spread equally from the tangential contacts over and to exclude air from the surface of the core, thereby completely covering the core with intimately contacting plastic material, and then vulcanizing the material.

8. The method of coating a core with vulcanizable material, which consists in placing a batch of plastic vulcanizable material in a mold portion, heating the mold por-- tion to increase the plasticity of the material, placing a core in tangential contact with the batch, placing another batch of the plastic material in another mold portion, causing the two portions to approach each other to spread the plastic material over and expel air from the surface of the core and heating both of the portions to vulcanize the material on the core.

9. The method of extending a vulcanized sheathing over an exposed portion of a core,

-which consists in placing a plurality ,of

spaced batches of vulcanizable plastic material 1n tangential contact with the core, ap-

plying pressure to the batches to spread the material thereof completely over and expel air from the-surface of the core and the;

end of the vulcanized sheathing, and then vulcanizing the material to thoroughly secureit to the core and to the previously vulcanized sheathing.

10. The method of coating :1 core with vulcanized material, which consists in placing a rod shaped portion of such material parallel to and in tangential contact with the core, applying pressure to the rod shaped portion to spread the material thereof over and expel air from the surface of the core and Vulcanizing the material.

11. The method of coating a core with vulcanized material, which consists in placing a plurality of separated cylindrical portions of vulcanizahle material parallel to and in tangential contact with the core, applying pressure to the portions to spread the material thereof over and expel air from the surface of the core, shaping the portions and vulcanizing the portions.

12. The method of coating a splice in a Vulcanized covered core, which consists in tapering the vulcanized covering on either side of the splice, forming the ends of a plurality of cylindrical portions of plastic material to conform to the tapered portions, placing the portions in tangential contact with the splice and in contact with the tapered portions, applying pressure to the cylindrical portions, causing the material to spread over and expel air from the surface of the core and the tapered portions, and vulcanizing the material.

13. The method of extending a vulcanized sheathing over an exposed portion of a core, Which consists in rubbing the vulcanized sheathing adjacent the exposed core with plastic vulcanizable material to remove loose particles of vulcanized sheathing and foreign matter from and to coat depressions in the sheathing with the material, placing a portion of the plastic material in contact with the prepared sheathing, and vulcanizing the material to thoroughly unite it with the yulcanized sheathing.

In witness whereof, I hereunto subscribe my name this 19th day of April A. 1)., 1923.

ARCHIE n. KEMP.

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