US1837733A

US1837733A - Protective covering and method of producing such covering

Info

Publication number: US1837733A
Application number: US445815A
Authority: US
Inventors: Harry C Stearns
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1930-04-19
Filing date: 1930-04-19
Publication date: 1931-12-22
Anticipated expiration: 1948-12-22

Description

Dec. 22, 1931. H. c. sTEARNs 1,837,733

PROTECTIVE COVERING AND METHOD OF PRODUCING SUCH COVERING F11-ed Apr-11 19, 1930 rPaxierlted Dec. 22, 1931 UNITED STATE-s PATENT oFFlcE.

HARRY C. STEARNS, OFOAK PARK, LLINOIS, ASSIGNOR TO WESTERN ELECTRIC COM- PANY, INCORPORATED, OF NEW YORK,

PROTECTIVE COVERING AND METHOD OF yPJEtODU'CINGr SUCH COVERING application mea April 19,

This invention relates to a protective covering and a method of producing such a covering.

The primary objects of this invention are to provide an improved protective covering anda method of producing the same in an eiiicient, economical and expeditious manner.

In accordance with the objects of this invention as practiced in one embodiment thereof in connection with the manufacture of protective coverings or envelopes, a cellulose derivative material is arranged in convolution form. Thereafter a portion of the ma-m terial is subjected to a solvent for coalescing the material to effect securement of the subjected portion.

Specifically this invention contemplates the provision of an insulating covering for an electrical coil and as practicedin this connection cellulose material in strand form is arranged in a plurality of layers of adjacent helices about the periphery of the coil, the inner end of the strand being intermediate the ends of the coil. Upon completion of the serving operation, which terminates at a point intermediate the ends of the coil, the unwound portion of .the strand material is severed and the free end of the helically applied portion thereof is secured from unwinding by dispensing/a small quantity of solvent to dissolve and coalesce the-material,- at the point where it is desired to sever the material and secure the free end of the helically applied portion thereof. Thereafter the en- 35 tire cellulose material forming the cover is treated with a solvent to dissolve portions thereof and effect complete coalescence ofthe naterial and produce an imperforate enveo e. j

I(,)ther 'objects and advantages of this in vention will more full v appear from the following description, ta en in connection with the accompanying drawings, wherein Fig. 1 is an elevational view of an electrical coil having a covering embodying-the invention and produced according to the improved method, part of the coil being broken away to more clearly illustrate the details of the structure;

50 Fig. 2 is an enlarged view of a coil show- N. Y., A. CORPORATION OF NEW YOE'K 1930. seran No. 445,815

ing the method of applying the coveriri thereto, only so much of the apparatus use being shown as is necessary to a complete understanding of this invention; f Fig. 3 is a fragmentary vertical sectional 55 View on the line 3 3 of Fig. 2; Fig. 4 is an enlarged fragmentary detail View taken on the line 4 4 of Fig. 3, and Fig. 5 is an enlarged fragmentary view of the coil shown in `Fig. 1, showing the -improved cover of this invention in various stages of completion. l rlhe type of fiber or strand employed may be of any ber or strand of a cellulose nature, such as the cellulose derivatives, which in a manner to be described later may be treated With a solvent to produce the effect desired. Examples of such materials are the strands of artificial silk which are made up of a pluralityA of synthetic filaments or ends. These strands may be employed for practicing the invention without any additional treatment. Strands of natural vegetable or animal'iibers, such as cotton or silk threads, may be employed but theymust be impregnated with a cellulose derivative, such as 4nitro-cellulose or celluloseacetate, before they are in condition for use. When the type of strand tobe used has been selected, lengths thereof may be arranged in an unwoven manner, such as solely in an unwoven warp formation, in the'formfof a web or in whateverother formis desired, which will permit the successful treatment as will bedescribed hereinafter.

When employed to form a 4waterproof and insulating cover foran electrical conductive winding 10 of an electrical coil (Figs. 1, 2 and 3), designated generally by the numeral 11 having a core 12 and endpieces or spool 90 .heads 13, the strand indicated at 14 is preferably arranged in a series of adjacent helices 15 comprising one or more layers. Re-

ferring particularly to Fig. 2 wherein the improved cover is shown in process of being produced, 17 and 18 indicate a rotatable spindle and a chucking element, respectively, adapted to receive the core 12 carrying the electrically conductive winding 10 thereon-l therebetween and rotate the same during the 10o" application of the cellulose strand 14C around the coil. A. supply (not shown) of the strand 14 is mounted in any convenient manner so as to permit the strand to be freely withdrawn therefrom upon the application of tension exerted thereon by the rotation of the coil 1l in the manner previously described. Suitable distributing means of a known type (notshown) maybe employed between the strand supply and the periphery of the coil l0 for distributing the strand ll longitudinally of the coil in adjacent helices l5. The serving of the cellulose strandjld is preferably begun at an appreciable distance from either of the heads 13, for instance at the point indicated at 20, and is continued to the left head 13, whereupon the serving of the strand is continued across the entire width of the coil to the right head 13, and then back to the point 20, thus serving two layers of helices l5 of the cellulose strand la around the winding 10.

Positioned immediately above the periphery of the coil 11 and in line with the point 20 where the beginning and ending of the servingoperation occurs isa liquid dispens ing apparatus (not shown) provided with a nozzle 23. After serving the strand ld in the manner previously described to the coil ll the rotatable spindle and chuclr l? and 18, respectively, are stopped and the operator actuates the dispensing apparatus and a small quantity of solvent for the cellulose derivative material is applied through the nozzle 23 to a portion of the strand at the point 20 (Figs. 2, 3 and d), which contemporaneously severs by dissolving the cellulose strand material from the supply and coalesces the free end of the strand served upon the coil to an adjacent portion of the strand to edect the securement thereof. lhis method of -securing the free end of the served cellulose strand providesa smooth peripheral surface to the coil ll and avoids any appreciable shrinkage of the strand at the point of securement sumcient to cause the end of the strand to brealr loose. At the time of dispensing the solvent onto the strand at the point 20 it is to be understood that the strand from the supply thereof (not shown) is under a minimum amount of tension sufiicient to separate the strand at the point 2G upon being dissolved by 'the solvent applied theret lhe solvent employed may be of any of the well known solvents for the cellulose derivatives. Acetone, however, is preferred be cause this material is a good solvent for both cellulose acetate and cellulose nitrate and is easily handled.. Other solvents, however, which may be employed are a mixture of ether and alcohol., tetrachloralethane, ethylacetate, diacetone alcohol, methylethyleketon or benzol acetate.

The next step in the method of producing` the improved cover consists in subjecting the Leary/aa assembled lengths of strands of cellulose material to a solvent of the nature hereinbefore referred to to produce an imperforate cover. The solvent may be applied in a number of ways, such ,as dipping the cover alone or in the specific cover described herein the cover and the coil enclosed therein in a bath of the solvent. As another exampleythe covers may be sprayed with a solvent or subjected to the vapor of a solvent during the boiling thereof. In any case the closely associated cellulose strands become partially dissolved or fused in a manner which might be termed autogenous agglutination. 'lhe closely associated cellulose strands thus coalesce or adhere to each other and after being dried to evaporate all of the solvent the finished imperforate covering presents the appearance as shown at 24 in Figs. l and 5. rlhe covering when completed is homogeneous and shiny on one surface where the solvent action has been applied to the cellulose strands,but on the opposite portion of the covering the strands will still be found to retain their original individual character.

The term cellulose material is used in the appended claims to refer either to fibers or strands composed entirely or partially of synthetic filaments or to natural fibers or strands impregnated with a cellulose derivative, and the term solvent as employed in the appended claims is intended to include plasticizers as well as true solvents.

What is claimed is:

l. A method of producing' a protective covering for a body, which consists in applying cellulose material in strand form from a supply thereof around the body, and subjecting a portion of the material to a solvent for severing it from the supplyl 2.v A method .of producing a protective covering for a body, which consists in applying cellulosematerial in strand form. from a supply thereof around the body, and sub jecting a portion of the material to a solvent for contemporaneously severing it from the supply and coalescing the material at its free applied end to an adjacent portion of the material to effect the secureinent thereof.

method of producing a protective covering for a body, which consists in applying cellulose material in strand form from a supply thereof in a plurality of adjacent helices around the body, subjecting a portion of the material to a solvent for contemporaneously severing it from the supply and coalesc/ing the material at its free applied end to an adjacent portion of the material to edect the securement thereof, and subjecting the helically applied material to a solvent to coalesce the adjacent helices.

el. A method of producing a protective covering for an electrical coil, which consists in applying cellulose material in strand form from a supply thereof in a plurality of adjacent helices around the coiled conductor, subjecting a portion of the material to a solvent for severing it from the supply, and

subjecting the helically applied material to a solvent to coalesce the adjacent helices.

5. A method of producing a protective covering for an electrical coil, which consists in applying cellulose material in strand form from a supply thereof in a plurality of layers of adjacent helices around the coil, the ends of the strand being intermediate the' ends of the coil, and subjecting a portion of the material to a asolvent for contemporaneously severing it from the supply and coalescing the material at its `free applied end to an adjacent portion of the material to eiect the securement thereof.

6. A protective covering for a body, consisting of a plurality of layers of helices of 'cellulose strand surrounding the body, the

ends vof the strand being intermediate the ends of the body and the outer end of the strand coalesced to an adjacent portion.

"7. A protective covering for an electrical coil, consisting of a plurality of layers of helices of cellulose strand surrounding the coil, the ends of the strand being intermediate the ends of the coil, adjacenthelices of the outer layer and the outer end of the strand being coalesced.

In Witness whereof, I hereunto subscribe my name this 9th da of April, A. D. 1930.

HA RY C. STEARNS.