USRE22078E - Sliver formation - Google Patents

Description

Aprilv21, 1942. R. c.' NEWMAN TAL R- 22,078

" sLIvER' FORMATION Original Filed Aug. 25, 1937 5 Sheets-Sheet 1 v as A 5, INVENTORS 52 YAM v ATTORNEYS.

3 Sheets-Sheet 2 l lil sel SLIVER FORMATION Ill R; c. NEWMAN Erm.

.Il ll Original Filed Aug. 25, 1937 April 2l, 1942.

April 21, 1942. R. c. NEWMAN Erm. Re 22,073

' sLIvER FORMATION -v Original Filed Aug. 25,' 1937 3 Sheets-Sheet 3 A TTORNEYS.

Ressued Apr. 21, 1942 I Re. '22,0789

Ralph C. Newman, Corning, N. Y., and John W.

Bomig, Rumford, B. I., assignors. by mesne assignments, to Owens-.Corning Fiberglas Corv 1 poration. a corporation of Delaware 'Original No. 2,202,118, dated May 28, A1.940, Serial No. 160,908, August 25, 1937. Application' lor I, reissue May 27, 1941, S I 4o Claims: `(Ci. 57-5) This invention relates to the formation and fabrication of fibres and fibrous materials. v

Heretofore, the preparation of yarns, rovings, and similar articles has involved a large number of manipulations of the basic fibres. This included various processes by whichl the fibres were separated, 'arranged in parallel relationship, formed into sliver, drafted, and twisted into yarn or thread. In the case of insulated coverings for wire it was often necessary to perform all of these operations and then braid or otherwise apply the finished yarn about the conductor.

The object of this invention .is to fabricate bulk fibrous materials into various desired ,articles such as yarns, rovings, and insulation coverings and the like of superior quality and physical characteristics and with a minimum amount of manipulation of the material, eliminating many of the conventional processing operations. Y

The principal feature of this invention is a process wherein raw materials are subdivided into separate fibres which are immediately gathered together into a body of annular configuration and then spun into any one of a number of desired forms.

In the accompanying drawings are disclosed a number of structures capable of carrying out this process in its basic forni and with numerous variations.

p In the accompanying drawings:

erin No. 395.412

device cooperating with the'spinning device to produce products of uniform diameter; and

Fig. 11 is an elevation showing the structural details of the mounting of the\ compacting rollers.

While this process has many advantages when performed in conjunction with the processing of natural iibres such as cotton, silk, and Wool,

and with the cellulose compounds commonly known/as artificial silk, it is in conjunction 'with the formation and use of ne filaments of thermoplastic substances such as glass, resins, and the like that it nnds its broadest applications.

The structure disclosed in detail is particularly designed to produce filaments of glass, commonly known as glass wool, although this structure may be operated' with equal efficiency in the A production of fibres of any other vthermoplastic mounted in a somewhat diiierent manner and I including an adjustable control baille;

Fig. 4 is an elevation showing details of the balie mounting and adjusting mechanism of Fig. 3;

Fig. 5 is an elevation. lpartially in section, of a spinning mandrel of somewhat different design especially adapted for cable manufacture;

Figs. 6, 7', and 8 are sectional'views of the mandrel of Fig. 5 modified to provide for application of various treating fluids to the fibrous materials being fabricated;

Fig. 9 is an elevation showing a pair of spinning mandrels arranged in series.

'device is lspinning a pair of oppositely twisted Alayers of insulation upon a conductor;

Fig. 10 is an elevation showing a compacting As illustrated, the

.substance normally solid at moderate tempera- In this device the thermoplastic sub-- tures. stance is melted electrically and divided mechanically into fine streams, which are in turn drawn into filaments of exceedingly ne diameter. for instance, by a jet of gas issuing at high speed from a blower 'surrounding the streams. It has been found possible to collect the ne fibres immediately after their production on a rotating body. In the accompanying drawings, the rotating body is disclosed as a generally cylindrical mandrel placed in the path of the fibres with its axis of rotation at 'right angles to the path of the newly formed fibres vwhich are directed adjacent toits surface by a draft of air being drawn into an adjacent vacuum chest. As the lfibres are deposited on this body in a heterogeneous, interlaced manner, layer on layer, a mass of fibres is built up about the surface of the mandrel.

Ifthe fibres constituting the edge of the felted mass are gathered together and drawn on! over the end of the mandrel, it will be found that they will in turn pullv adjacent fibres with them and thus apply a tractive effort which promotes gradual movement of the entire mass toward the end of the mandrel. If the rate of lineal movement of the withdrawn fibres is properly regulated with respect to the rate atwhich additional fibres are being deposited on the mandrel, the mass will remain substantially constant as to area and volume, fibres being withdrawn and the mass being replenished continuously over an indefinite period.

In withdrawing. fibres from the mass, it has been found advisable to move the fibres in a straight line along the axis of rotation of the mandrel for an appreciable distance after which they may be diverted `as desired. No rotation is imparted to the withdrawn fibres so the continuous rotation of the mandrel will produce relative rotation betwen the withdrawn fibres' and the mass from which they are withdrawn. Thus what would otherwise be a cylinder 'of interlaced bres of the same diameter as the mandrel is spun downinto a twisted yarn whose weight and degree of twist are determined by the rate of production of the fibres, the speed of draw and the speed of rotation of the mandrel. However,I on examination of the resulting yarn it will be found to retain an essentiallyv tubular construction.

The fibre forming device and winding mecha- `nism which are shown in the drawings areof standard manufacture and no claim is laid to the mechanical details of these structures save in combination with the novel collecting and spina.

ning mechanism, This mechanism consists essentially of a hollow mandrel, suitable means for driving this mandrel at various speeds, and suction means to aid in the collection of fibres about the surface of the mandrel. In general it'has been" found that a single suction chest placed beneath the mandrel and having a perforate upper surface closely adjacent thereto is ample to effect collection of the iibres as desired. Such a suction chest draws a considerable volume of 'air about the mandrel and the fibres, borne in this body of air, are brought into .close proximity to the mandrel. It has been found that the fibres will collect in a uniform` felted mass about the mandrel without any mechanical means which is to be covered, but may advantageously constitute a conduit for the application of vari- Gil ous treating substances such as lubricants, sizes, and impregnants to the fibres as Vthey are spun from the end of the mandrel. Inspinning down vthe felted cylinder of fibres to a yarn or conductor covering, a cone of interlaced bres is formed adjacent the nose of the mandrel. VBy attaching a spray nozzle or similar means to the end of the .hollow shaft, treating substances may be sprayed on the interior of this cone of bres resulting in a very thorough application o f the substances to the fibres with a minimum of waste, such loss as occurs taking place only by passage of the substance through the cone of interlaced fibres. By the provision of a special head which has both nozzle and guide openings, it is possible to spray impregnants and adhesives beattracting them thereto, but it is advantageous Vin certain instances to perforate the surface of the mandrel and evacuate its interior, thereby drawing the fibres down into contact therewith.

libres to pull away therefrom under the influence .of centrifugal force. It has been found possible toy control the cohesion between the mandrel and fibres by placing a baille plate within-the mandrel which limits the applicationof suction to a portion onlyof the surface of the mandrel. By adjustment of this baille longitudinally of the mandrel the area to which suction is applied may be increased or decreased while angular adjustment about the axis of the mandrel, permits ad-V justment of .the suction area with respect to the descending stream of fibres and may be used to secure uniform deposition of the fibres on the mandrel. l

Since a yarn of generally tubular construction `is produced by this method` of spinning, the

process'naturally suggests itself as a means for producing insulating coverings on electrical conductors.

j these arrangements an opening is provided in To accomplish thisA a passageway", through the rotating mandrel is provided prefthe nose of the mandrel, which nose may be removable and varied as to contour according to the type of product which is desired.

The hollow shaft passing through the mandrel is not only userulas a guide furthe conductor thermoplastic material from which the fibres aretween the cone of interlaced bres and a conductor producing an impregnated covering on a -conductor in a single operation.

A still further use may be made of the hollow shaft. By providing perforations along its length and along the surface of the mandrel, it has been found possible to apply mixtures of oil and. similar treating substances to the bres `as they are deposited on the surface of the mandrel thuseliminating the necessity of an open spray adjacent the blower. Y

When certain treating substances, notably sizes and impregnants, are applied to the fibres, it is often advisable to compact the yarn or conductor covering so as 'to render it solid and of uniform diameter.A This may be accomplished by various mechanical devices such as dyes, burnishing plates, and the like, but the drawings illustrate a structure in which the yarn or conductor passes through a pair of grooved rollers shortly after` it h'as been sprayed with the treating substances. 'I'he configuration of these rollers and their setting determine the extent to which the nbres are Y compacted. If the rollers are moved circumfer entially about the conductor as lt is drawn therethrough, a wiping action takes place which produces a 'superior finish on the product. The movement given to the rollers should be so chosen as to correspond generally to the direction in which the fibres lie in the surface of the yarn or conductor covering.- l

It will, of course, be obvious to thoseacquainted with the manufacture of insulated wire and cable that a battery of these spinning mandrels may be set up to operate one after another on a single conductor, spinning a series ofV concentric coverings thereonf. In such an arrangement adjacent mandrels are rotated in opposite directions to produce opposite Vtwists in adjacent layers. This same arrangement of equipment may be used to produce a novel yarn. `Ii. the con-A ductor be omitted and the yarn from one mandrel run through a second, rotating in the opposite direction, a yarn will be produced having a core twisted in one direction and a seamless outer layer twisted in the other direction. Since these two twists oppose each other, the yarn has no tendency to twist on itself and kink.

' Referring in more detail to the specific structure disclosed in this application, it will be seen that there is disclosed diagrammatically in Fig. 1

a fibre forming mechanism such as is shown in detail in the British patent to Triggs No. 428,720, dated May 17, 1935. In such a structure the to be formed is melted in a refractory container Il and issues from the bottom'thereof through openings in an electricallyheated bushing plate I5. The issuing streams of thermoplastic material are cooled and attenuated to filaments of minute diameter by the action of a jet of gas is- Directly beneath the bushing is positioned aI spinning unit which consists of a rotatable hollow mandrel I9 and associated vacuum chests 20 and 2l which are connected with a suitable suction device by ducts 22 and 23. As shown in more detail in Fig. 2, the mandrel lil consists of a perfor'ate cylindrical' metal shell 24 andtapered head 25 mounted upon the shaft 26. This shaft is journaled in bearings 21 and 28 and may be rotated at any desired speed by the variable speed electric motor 2! operating through belt 30 and pulley Il. A series of registering holes 32 in the end plate Il of the mandrel and the adjacent wall 3,4 of the vacuum chest 2| permit partial evacuation of the mandrel.

As the newly formed fibres pass downwardly from the blower they are caught in the current of' air being drawn into the vacuum chest 20 through its upper surface I which may be made of Wire mesh or other perforate material. This vacuum chest is so positioned and shaped with respect to its-surface 35 that it directs the fibres about the rapidly rotating mandrel where they are deposited and formed into a sheath-like layer. This layer is continuously withdrawn from the end of the mandrell by the adjacent winding mechanism designated generally at 36. This Mechanism may be of any desired type but as shown consistsof a friction drum 31 driven by belt- 3B at the desired speed by a variable speed motor 39. The withdrawn fibres are spun down into a yarn or conductor covering adjacent the nose of the mandrel which rpasses through a fixed guide 40, located in axial alignment therewith, and the eye 4| of a conventional traverse mechanism 42. The finished material is wound about the cylinder 43 due to frictional contact with drum 31.

While it has been found that the descending fibres will wrap themselves about the mandrel in a satisfactory manner solely under the action of the vacuum chest 20, it has been found desirable, in certain instances, to at least partially offset the centrifugal force` acting on the fibres due to the high speed of rotation of the mandrel.

This may be accomplished by'developlng a partial vacuum in the mandrel through-communication with the vacuum chest ZI in the manner described above or by a somewhat different mounting for the mandrel as shown in Fig. 3. In this structure the central shaft is eliminated and an extension 44 of the shell of the mandrel 45, slightly reduced in diameter, forms a shaft which is journaled in bearings 4Q and t1 and to which power is applied for rotation through pulley 48. The end of this shaft projects into a vacuum chest 49 so that a partial vacuum mayv be established within the mandrel. With this arrangement of parts, we place a control baffle 5I) within the mandrel to confine the application of vacuum to a portion of the surface thereof. This baille is adjustably mounted by means of rod 5i for movement both longitudinally and rotatively within the mandrel. The support for rod 5B shown in detail in Fig. 4 includes a fixed bracket 52 and a rotatable plate 53 concentrically mounted with respect to the mandrel 45 and sleeve 44. Movement of the rodll with respect to plate 5I is controlled by set screw 54 while rotation of -plate 53 within the bracket 52 is controlled by set screw 55. The extent to which suction is applied about the circumfer- 'ence of the mandrel may be modified by variation in the configuration of the baille.

As has been stated above. thoroughly satisfactory results have been obtained without evacuation of the mandrel and it is this mode of operation which permits the use of a variety of mandrel designs each particularly adapted for a different function. The hollow rotating shaft of Fig. 1 is satisfactory when a bare copper conductor is being covered but when it is desired to apply consecutive layers of insulation as in the case of cable manufacture, it has been found desirable to provide a central conduit through the mandrel which will not rotate with respect to the cable. Such a structure is shown with A various modifications in Figs. -.fi to 8. In Fig. 5

1 rigidly clamped in a supporting bracket 51.

the hollow central shaft 56 of this structure is In this design the mandrel is made up in two sections 58 and 59 threaded together at 60. Ball bearing assemblies BI and 52 carried in these sections of the mandrel permit it`to rotate as desired about shaft 56. The heavy hub 63 within which bearing 82 is positioned is grooved to accommodate a V-type belt connected to any suitable prime mover.

Fig. 6 discloses slight variations in the above structure. By providing a connection 65 with ra source of supply and a sprayhead 66, shaft 56` becomes a spraying device. The spray head such as is shown in Fig. 7 combines the functions of guide and spray. A central aperture 61 properly supports and centers the conductor 6B while lateral openings 69 direct a spray of the desired materiall against the interior of the cone of fibres 10. y

The structure disclosedin Fig. 8 constitutes a still further modification of the basic structure of Fig. 5. In this instance no treating materials' issue from end of shaft 56 but lateral openings 1I and 12 in the shaft and mandral respectively permit treating fluids in mist or vapor form to reach the fibres deposited on the exterior of the shell. We have found this structure an improvement over` the simple spray I8 of Fig. 1 in coating the fibres with tempering and lubricating oils.y A .relatively slight pressure is sufficient to supply the vapor or mist to the mandrel and force it therefrom. In this case, as in the structures of Figs. 6 and 7, material savings ofy treating fluids are effected over previous methods since they are applied within a body of fibres and ,this nature arranged in series for the application of successive layers of fibres, one outside the other, as a straight line operation.` The typev of mandrel which has been used in this instance `is the same as that disclosed in Figs.' 5 to 8. The

illustrated structure consists of fibre forming units designated generally as 13 and 14, mandrels 15 and 16, and suction chests 'I1 and 18. The mandrels are mounted in substantial axial alignment and are rotated from reversible electric motors 19 and 80 sothat they may be rol(ated yin the same or opposite directions. A

suitable device for withdrawing the spun fibres is, of course, included in the working assembly Fig. 9. As shown in Fig. 9, a conductor is lpassing through the mandrels and is receiving two coatings of fibres which are being twisted in opposite directions.f y n In Fig. 1041s shown a compacting device which may advantageously be used in conjunction with the spinning apparatus. This mechanism consists of a rotatable disk Bi mounted in axial alignment with a spinning mandrel 82 and bearing a pair of compacting rollers Il and 8l. These rollers are provided with complementary grooves in their respective faces designed to receive a yarn or cable therein and impart thereto a uniform circular cross section. The brackets 85 and B8 by which those rollers are mounted are adjustably fastened to the face of the disk 8| by means of studs 81 so as to -provide for radial movement of the rollers with respect to the axis of rotation of the disk. l Rotation of the disk is effected through gearing 88 on lthe periphery thereof and a pinion I9 driven by a variable speed motor 9D. As `the yarn or'cable advances through the compactlng device the radial pressure of the rollers and the circumferential wiping action resulting from rotation of the disk imparts a smooth finish and uniform diameter to the same. In the case of sized yarns and impregnated cables this device aids in incorporating the uid material throughout the mass of bnes whether such materials be sprayed on externally as from pipes 8| in Fig. 10 or internally asinFigs.6and7.

While this invention has been disclosed primarily with respect to a structure in which fibres are artificially formed and are immediately collected on the spinning mandrel, it has been found that satisfactory results will be obtained when natural fibres are employed and are delivered to lthe spinning mandrel from the usual carding, picking, and stapling machines commonly employed'in libre preparation in the tex'- tile art and various rotating bodies of diii'erent coniiguration may be substituted for the specic mandrel disclosed.

This specific disclosure is by way of illustration and the invention is to be limited only by the scope 'of the appended claims.

We claim t l. The method of manufacturing fibrous materials comprising the steps of preparing a quantion between said conductor and said body whereby .said annulus is spun down as a vseamless twisted coating on said conductor.

4. The method of fabricating an insulated conductor which comprises preparing a felted tubular body of iibrous material, passing a conductor axially through said v'tubular body 4and twisting and elongating said body *about said conductor thereby forming a tightly spun coating ofliibrous insulation thereon.

5. The method of forming an insulated conductor which comprises forming a seamless felted mass of iibrous insulating material about a conductor but spaced therefrom, spinning said mass l5.

down yinto contact with said conductor, and slmultaneously spraying an impregnating material between said conductor and said insulating material.

'I'he method of forming a'yarn which comprises preparing a cylindrical felted mass vof iibres, rotating said mass, continuously withdrawing a cone of bres from one end of said mass in.

the direction of its axis of rotation, and spraying the interior of said cone with a treating material while it is being withdrawn.

'1. The method of forming a yarnwliich com prises preparing a twisted yarn, passing said yarn through a rotatingvmass of intermingled bres and spinning said mass ofbres down onto said A yarn to form a seamless layer of interlaced fibres thereon. said spinning being in such a direction as to form a layer of opposite twist to-the twist of the. core. y

8. In combination, means for producing a con- Y tinuous supply of fibrous material, means adja-v l cent thereto for collecting said fibres in the form of a felted cylindrical mass, said collecting means vcomprising a rotating cylindrical mandrel and means `for creating a region of sub-atmospheric pressure adjacent the surface thereof, and means adjacent said' collecting means for withdrawing said libres axially of said means;

9. In' a fibre collecting `and spinning mechanism, a rotatable fibre collecting mandrel and a.Y

. hollow shaft extending substantially through said mandrel and forming a passageway theretity of separate flbres,'intermingling said libres and forming them into an interlaced, internally supported mass o'f annular configuration, rotating said annular mass and continuously applying tractive force to an extremity of said mass to .Y withdraw a body of ilbres therefrom.

`3; The method of fabricating insulated oo nductorswhlch comprises building up a felted annular mass -of'iibrous insulating material about a rotating body, continuously withdrawing an anv nulus of fibres from one end of said`mass, passing a conductor through the center of said rotating body and into the center of said annulus, simultaneously withdrawing said annulus and said.'

conductor at the same linear speed in a direction parallel to the axis of rotation of said aforementioned body and establishing relative rotathrough. i

l0. In a libre collecting and spinning mechanism, arotatable mandrel, said mandrel having a cylindrical body section and a tapered nose section, an openingdn the tip of said nose section, and a hollow shaft extending substantially through said mandrel.` said opening in the nose section being in register with the end of said shaft, and a spray nozzle on the end of said shaft for spraying iiuid substances'through said opening.

1l. In a'wire covering device. means for forming fibres into a cylindrical felted mass, means for drawing oil' a cone of libres from one end of said mass, and means positioned within said mass for introducing a conductor into the center ofsaid cone oi' fibres in a direction axially thereof.

12; In a wire covering device, means vior forming fibres of insulating material into a cylindrical felted mass, means for drawing off a cone of fibres from one end of said mass, means positioned within said mass to guide a conductor into the center of said cone of fibres and means adjacent said guide means for spraying fluid sub stances against thev interior of said cone.

13. In a yarn forming device, means for forming textile libres into a cylindrical, felted mass, means for 'drawing ofi' a cone of fibres-from one end of said mass and twisting Vthem into a yarn 4 mass of fibres from the interior thereof.

and means positioned within said forming means for applying iiuid substances to said cylindrical 14. In combination, spinning means for depositing a seamless felted coating of insulating fibres about a conductor, spray device adjacent said spinning means to treat said covering after it has been spun about the conductor, and compacting means adjacent said spray and bearing against said conductor to press said libres together to form a dense body of uniform diameter.

15. In a yarn forming device, means for forming textile fibres into a cylindrical, felted mass, means for drawing ofi a cone of fibres from one end of said mass and twisting theminto a yarn, and spraying means positioned within said forming means to spray fluid substancesagainst the interior of said cone of lbres. l

16. The method of fabricating fibrous material which comprises building up a felted annular mass of fibres about the surface of a rotating body, and continuously withdrawing an annulus of fibres from one end of said mass while continuously building `up said mass by the`applica tion of additional fibres thereto.

1'1. The method of fabricating fibrous material which comprises building up a felted annular mass of fibres about the surface of a rotating body, continuously withdrawing an annulus of fibres from one end of said mass while continuously building up said mass by the application of additional fibres thereto and maintaining relative rotation between said annular mass and said withdrawn fibres whereby said fibres are spun into a yarn.

18. The method of forming a yarn which comprises vpreparing a cylindrical felted mass Aof fibres, rotating said mass, continuously withdrawing a cone of fibres from one end ofsaid mass in the direction of its axis of rotation,

'spraying the interior of said cone with a treating material while it is being withdrawn and twisting said cone with respect to its apex to spin it down into a yarn. l

19. The method of forming a yam which comprises preparing a twisted yarn, passing said yarn last named means being adjustableto vary the linear speed of withdrawal of said fibres.

23. In a yarn forming device, a rotatable mandrel comprising a cylindrical body portion and a. tapered nose portion, a hollow shaftpositioned within said mandrel, and registering openings in the end of said shaft and the tip of said nose providing a passage from the interior of said shaft through said mandrel;

24. The method of manufacturing fibrous materials comprising the steps of preparing a quantity of fine air borne glass fibres, collecting said fibres about the outer surface of a rotating member to form a body of interlaced fibres, and withdrawing a portion of said bres in the direction of the axis of rotation of said rotating member.

25. The method of preparing fibrous material which comprises the steps of preparing a quan- `tity of separate, long, fine glass fibres, interthrough a rotating mass of intermingled fibres and spinning said mass of fibres down onto said yarn to form a seamless layer of interlaced fibres thereon, said body of fibres being rotated to produce a different twist in said layer from that in said yarn. Y

21. The method of treating yarn which comprises forming a cone shaped web of interlaced fibres, spinning a tubular yarn from the apex of said cone, spraying a treating solution against,y

the interior of said cone during the spinning operation and compressing said yarn to render it compact and of uniform diameter.

22. In combination, means for producing a continuous supply of fibrous material, means adjacent thereto for collecting said fibres in the` form of a felted cylindrical mass, said collecting means comprising a rotating cylindrical mandrel and means for creating a region of subatmospheric pressure adjacent the surface thereof, and means adjacent said collecting means for withdrawing said fibres axially of said' means, said 75 mingling said fibres and forming them into an interlaced, `internally supported mass of annular configuration, rotating said annular mass and continuously applying tractive force to an ex.

ytremity of said mass to withdraw a body of fibres therefrom.

26. The method of fabricating insulated conductors which comprises building up a felted annular mass of fibrous glass insulating material about a rotating body, continuously withdrawing an annulus of fibres from on'e end of said mass, passing a conductorthrough the center of said rotating body and into the center of "said annulus, simultaneously withdrawing said annulus and said .conductor at the same linear speed in a direction parallel to the axis of rotation of said aforementioned body and lestablishing relative irotation -between saidconductor and said body y whereby said annulus is spun down as a seamless twisted coating on said conductor.

2'1. The method of fabricating an insulated conductor which comprises preparing a felted tubular body of fine glass filaments, passing a conductor axially through said tubular body and twisting and elongating said body about said conductor thereby forming a tightly spun coating of fibrous insulation thereon.

`28. The method of fabricating fibrous material which comprises building up a felted annular mass of long, flne glass fibres about the surface of -a rotating body, and continuously ,withdrawing an annulus of fibres from one end of said mass while continuously building up said mass 4by the application of additional fibres thereto.

29. The method of fabricating fibrous material which comprises building upa felted annular mass of long, fine glass fibres about the surface of a rotating body, 'continuously withdrawing an annulus of fibres from one end of said mass while continuously building up said mass by the application of additional fibres thereto and maintaining relative rotation between said annular mass and said withdrawn fibres whereby drawing said fibres axially of said means, saidl last n amed means being adjustable to vary the linear speed of withdrawal of said fibres. l

31. combination, means for producing a wcontinuous supply of long, ne glass fibres, means adjacent thereto for collecting saidiibres in the form of a felted cylindrical mass, said collecting meansf comprising a' rotating cylindrical mandrel and means for creating a region of subatmospheric pressure adjacent the surface thereof, and means adjacent said collecting means forwith-l drawing said fibres axially of said means.

32.. The method of fabricating strand material of fibrous glass which comprises attenuating a multiplicity of molten glass streams to form flbres. collecting said fibres immediately after they are formed, layer on layer into an internally supported hollow mass of libres, gradually moving said mass toward an axial extremity thereof without substantial decrease in diameter, 'and' drawing the fibres of the mass1 at said axial extremity down into a strand.

33. The method of fabricating strand mate-A rial of fibrous glass which comprises attenuating a multiplicity of molten glass streams to form fibres, collecting said fibres immediately after they are formed, layer on layer into a rotating mass of substantially annular configuration,

port while simultaneously moving said annulus away from said .extremity to continuously forni the annular mass into a strand, .and continuously building up said mass on said support with additional newly formed fibres.

36. In combination, means for producing a continuous supply of fibrous glass material and means for collecting said fibres in the form of a,

, substantiallyV cylindrical mass, said collecting gradually moving said rotating annular mass toward an axial extremity thereof. and spinning the fibres of said annular mass as theyleave said extremity into a strand of intermingled fibres.

34. The method of fabricating strand material of fibrous glass which comprises attenuating a multiplicity of molten glass streams to form ilbres, collecting said fibres directly from the place of formation layer von layer into an internally supported tubular mass of! substantially uniform diameter, rotating said mass and gradually moving said mass toward an axial extremityV thereof without substantial decrease in'diameter. drawing down the mass as it leaves said extremity into a fibrous body of reduced diameter, and

maintaining relative rotation between said mass and said body of reduced diameter, whereby said body is spun down into a yarn of intermingled fibres.

I 35. The method of fabricating glass brous strand materiaLwhich comprises drawing out a plurality of streams of molten glass into the form of fine fibres, irnmediatelycollecting said :libres layer on layer on a rotating support to form an internally supported hollow mass of bres. moving said mass axially of said support toward an extremity thereof. reducing the diameter of an annulus of fibres at the extremity of said sup.-

means comprising a rotatable substantially cylindrical support, and means for moving said cylindrical mass axially of said support and oil? said support at one end thereof.

37. The method of fabricating insulated conductors which comprises building up an internally vsupported substantially annular mass of fibrous glass insulating material, continuously moving an annulus of fibres away from one end of said mass, passing a 'conductor through the A center of said annulus in the direction of movement of said annulus, simultaneously moving saidI annulus 'andsaidl conductor at the same linear speed in a direction parallel to'the axis of rotation of said mass and establishingrelative rotation between said mass and saidannulus whereby said annulus is spun down as a seamless coating on said conductor. v

38. The method of fabricating an insulated "conductor which comprises preparing a tubular body vof glass fibrous material, passing a conductor axially through said tubular body and elongating said body about said conductor, thereby forming a tightly fitting coating of fibrous insulation thereon.

39. The method of fabricating fibrous material which comprises building'upan annular mass of glass fibres about the outer surface of a cylindrical body. andv withdrawing an annulus of fibres from one end of said mass and causing the annular mass to follow said annulus and be drawn (from said body and lengthened outl to form a narrow continuous tubular strand.

40. The method of fabricating fibrous material which comprises superimposing layers of glass fibres about the surface of a rotating body to Vform an annular mass, and continuously withdrawing an annulus ofl fibres from one end of' said lmass while continuouslyl building up said mass by the application of additional fibres there- RALPH c. v JOHN w. RoMIG.

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