US1883155A - Method of coating electrical conductors - Google Patents

Description

Uct. 18,1932. K. M. WATSON METHOD OF COATING ELECTRICAL CONDUCTORS Filed Aug. 30, 1930 //1venf0r K M Watson w/ q y Patented a. 1a, 1932 UNITED STATES PATENT OFFICE KENNETH M. WATSON, OI CHICAGO, ILLINOIS, ASSIGNOR TO WESTERN ELECTRIC COE- PANY, INCORPORATED, OF NEW YORK, N. Y., A. CORPORATION OF NEW YORK METHOD OI COATING ELECTRICAL CONDUCTORS Driginal application filed December 16, 1926, Serial No. 155,808. Divided and this application filed August 30, 1930. Serial No. 479,066.

This invention relates to methods of coating electrical conductors, and more particularly to methods of baking a coating of insulating enamel upon a wire, and is a division of m copendin application Serial No.

led December 16, 1926.

The primary object of this invention is to provide a simple and efiicient method of economically and expeditiously baking a coat- ;ing on electrical conductors.

In order to obtain these and other objects and in accordance with the general features of the invention, one embodiment thereof in an apparatus by means of which the method may be etficiently practiced includes apparatus for continuously passing a wire through a bath of insulating material. The wire prior to its entrance into the insulating material is passed over a pulley which forms one ter- 20 minal of a source of electrical current supply, and subsequent to this coating operation the wire is passed over a rotary member which forms the other terminal of a source of the electrical current supply. blades carried by the rotary member penetrate the insulating coating and contact with the wire, thereby including an ever-changing wire portion of constant extent within an electrical circuit, the current passing therethrough serving to heat the wire and thereby bake the insulating coating. Restricted openings formed in the coating during the penetration of the blades completely close due to the normal flow of the insulating coating, thus presenting a wire coating which is of a uniform and homogeneous character.

These and other objects will be apparent from the following detailed description, reference being had to the accompanying drawing in which Fig. 1 is a fragmentary side elevational view, partially in section of a wire insulating apparatus, a circuit diagram including a source of low frequency current supply being shown in association therewith, and

Fig. 2 is an enlarged fragmentary sectional view of the rotary member taken on the line 2-2 of Fig. 1.

Referring now to the drawing, wherein 60 like numerals have been employed to desig- Sharp edged nate similar parts throughout the various figures, it will be observed that a wire supply spool is carried by abracket secured on the side of a suitable machine frame 11. Wire 13 from the supply spool 10 passes downwardly over a metallic pulley 14 which is mounted upon a bracket 16 secured to the machine frame 11 and electrically insulated from the bracket by means of an insulating bushing 17. From the pulley 14 the wire 13 is directed downwardly into a bath of insulating material 19 within a suitable container 20 and is guided therethrough by means of a pulley or sheave 21 rotatably'mounted with-.

in the container. After passing through the bath 19 the wire is directed upwardly through a heating chamber 22 and passes over a pulley or sheave 23 which is supported by the upper endof a vertical bracket 24 suitably mounted upon the upper portion of the machine frame 11. The wire is then fed downwardly from this sheave 23 to a sheave (not shown) companion to and in alignment with the sheave 21 and then upwardly over an idler guide pulley 25. From the pulley 25 the wire is passed over a rotary metallic member 26 which is provided with a plurality of sharp edged blades 27 of electricalvconducting material and then to a receiving spool 29 WlllCll may be driven from any suitable source of power (not shown), the speed of the spool being regulated to the speed at which it is desired to feed the wire upwardly through a heating chamber 22.

The rotary member 26, which is slotted to receive the blades 27 and provided with peripheral flanges 30 (Fig. 2), is mounted upon a suitable support 32 and is electrically insulated therefrom by an insulating bushing 33. It will be observed that this rotary member 26 and the pulley 14 form opposite terminals of an electrical circuit which includes a suitable source of low frequency electrical current supply 35, a switch 36, a transformer 37, a swltch 38 and an adjustable resistance 39. The circuit including the secondary winding of the transformer 37 may be traced in part from a spring brush 42 engaging with a hub on the pulley 14 through the adjustable resistance 39, through the secondary winding of the transformer 37, the switch 38, and thence to a spring, brush 43 engaging a hub on the rotary member 26. a ,Theblades 27, suitably secured within companion slots of the rotary member 26, extend slightly beyond the periphery thereof and when a coated wire from the sheave 23 passes over the rotary member, the sharp edges of these blades successively penetrate the coatingand contact with the wire (Fig. 2), thus completing the secondary circuit, above described, by establishing an electrical connection between the rotary member 26 and the pulley 14 through the portion of the wire 13 extending therebetween. From the foregoing it will be clear that when the switches 36 and 38 are closed and the electrical circuit is completed through the wire 13 as described, current will flow therethrough and by proper adjustment of the resistance 39, the heat generated thereby within that portion of the wire may serve to effectively bake the coating of insulating enamel previously applied to that portion. In this connection nit is to be understood that a plurality of tively preclu 40 sheaves similar to the, sheaves 21 and 23 might be employed, the-number of sheaves being dependent upon the number of times it is desired to pass the wire through the coating compound and through the chamber 22 before passing it over the blades 27. The member 26 is freely rotatable in the support 32 so that as the coated wire is drawn over the blades 27, the speed of travel of the wire and the blades will.be the sameand hence any tendenc .to causea relative movement between t e sharp edges of the blades and the coating through which they penetrate is posied. By this construction the size of openings or incisionsmade in the coatings are kept within desirable restricted I 'hmits.

In some instances it is desirable to control the temperature of the, coated wire 13 as it passes over and is carried into contact with the blades 27. The reason for this will be obvious wthenit is understoodthat as the wire 13 contac s with a blade 27, it is desirable to have the blade and the member 26 in whichv 'it is mounted at substantiallythe same temblade, there might.

transfer of heatfrom the wire to the rotary perature as the wire. Should the wire be at a much higher tem erature than that of the a tendency for a quick I member 26 which would result in a sudden contraction of the wire and hence the possible scraping of the blade thereon. This scra ing might have a tendency to enlarge t e incision made by the blade, and obviously it is desirable to make the smallest possible incision in effecting the contact. between 'the blade and the wire. In order to render possi ble this temperature control a pipe 45 having a communication with a suitable source of water supply (not shown) through a valve 46 is adapted to project a stream of water or other suitable quenching medium upon the coated wire as it approaches the blades 27 and in this manner the temperature of the rotary member 26-and the wire 13 may be properly regulated.

By the practice ofthis improved method an electrical heating current may be passed through successive, ever-changingportions 'of a coated wire of'uniform len h, this length being determined by the extent of wire reaching between the blades 27 and the metallic pulley 14. In the disclosure a source of low frequency current supply 35 has been practiced which renders possible the direct i contact of a terminal (the blades 27) of a source of electrical current supply with a moving coated wire, one of the blades alwaysbeing in contact with the conductor, thereby eatly facilitatin the baking of the coating 1 y the passage 0 a low frequency current through an ever-changing constantjportion of the wire.

It is to be understood that the invention is not limited'to the exact construction and functional characteristics herein described and that the appended claims have been drawn to define other modifications which.

come'within the true spirit and scope of the invention.

What is claimed is: 1. The method of insulating an electrical conductor, which consists in coating'the eonductor, and then making a direct contact with the conductor through the coating thereof to connect the conductor with a source of electrical current supply, thereby heating the conductor to bake the coating.

The penetrations or incisions 2. The method ofinsulating an electrical conductor, which consists in coatin the conductor, and then passing a low requency electrical current I through ever-changing portions of the conductor of constant extent,

thereby heating the conductor to bake the coating. v 3. The method of insulating an electrical conductor, which consists in-coating the conducto'r, directly contacting one terminal of a source of electrical current supply with an uncoated portionof the conductor, and then penetrating the coating 'to directly contact the other terminal of the source of current supply with the; conductor, thereby heating the conductor to bake the coating.

4. The method of insulating an electrical conductor, which consists in coating the conductor, and then connecting the conductor with a source of electrical current supply by penetrating the coating and contacting with the conductor to cause an electrical heating current to pass therethrough and bake the coating. v

5. The method of insulating an electrical conductor,'which consists in coating the con ductor, making a direct contact with the conductor through a restricted opening in the coating thereof to connect the conductor with a source of electrical current supply, thereby heating the conductor to bake the coating and then closing the restricted opening in the coating.

6. The method of insulating an electrical conductor, which consists in coating the conductor, connecting the conductor with a source. of electrical current supply by penetrating the coating and contacting with the conductor to cause an electrical heating current to pass through the conductor for baking the coating, and controlling the temperature of the conductor during the contacting of the terminal therewith.

7. The method of insulating an electrical conductor which consists of moving a conductor through an insulating icompound, making an electrical contact therewith prior to the conductor entering the compound, making electrical contact with the moving conductor through the insulating coating thereon at predetermined spaced successive points from said first contact, and passing an electrical current through said contacts to the .conductor to bake the insulating coating thereon. I

In witness whereof, I hereunto subscribe my name this 22nd day of August A. D. 1930.

KENNETH M. WATSON.

Images