US2720728A - Glass fiber drawing apparatus - Google Patents

Description

Oct. 18, 1955 J. F. COURTNEY ETAL 2,720,728

GLASS FIBER DRAWING APPARATUS Filed July 12 195] Cladt/ i e P 72 /en fans. vfi f? ('ourfize Maze [barf United States Patent GLASS FIBER DRAWING APPARATUS Joseph F. Courtney, Evanston, and Adelbert C. Radtke, Oak Park, 111., assignors to International Harvester Company, a corporation of New Jersey Application July 12, 1951, Serial No. 236,414

3 Claims. (Cl. 49-17) This invention relates to apparatus for attenuating thermoplastic material and has particular reference to the manufacture of glass filaments.

A general object of the invention is to provide a simple mechanism for grasping the material with mild pressure along a sinuous relatively extensive surface while imposing an attenuating tensile force thereon.

A more specific object is to provide a drawing assembly incorporating a pair of opposed rolls each of which comprises a peripheral section of readily distortable rubber with perforations therethrough designed to obtain a plurality of expansible segments formed and arranged to displace radially outwardly different distances under the influence of centrifugal force pursuant to rotation of the rolls to provide a scalloped peripheral surface profile on each roll and which is adapted to engage the fibers entered between the rolls and to cause conformance of the fibers to said surface in intimate contact therewith as the fiber is being passed between the opposed contacting portions of the rolls.

A further object is to form and arrange the perforations in such manner as to obtain a substantially symmetrical undulation of the peripheral surfaces of the rolls throughout the entire circumferential extent thereof.

Certain embodiments of the invention contemplate the provision of peripheral blower passages through the outer edges of the drawing wheels to accentuate stripping of the material from the rolls.

These and other objects of the invention will become more apparent from the specification and the drawings, wherein:

Figure 1 is a side elevational view of one embodiment of the drawing mechanism with environmental components shown diagramatically.

Figure 2 is a radial sectional view taken substantially along the line 22 of Figure 1.

Figure 3 is a fragmentary side elevational view of another form of the invention.

Figure 4 is a fragmentary enlarged side elevation of the embodiment of Figure 3.

Figure 5 is a transverse sectional view taken substantially on the line 55 of Figure 4.

Figure 6 is a fragmentary side elevational view of another form of the invention.

Figure 7 is a fragmentary edge view of one of the drawing elements shown in Figure 6, and

Figure 8 is a sectional view on line 88 of Figure 7.

Describing the invention in detail and referring first to the embodiment shown in Figures 1 and 2, the furnace 2 contains molten glass which is arranged to descend through a plurality of apertured bosses 4, 4 of a bottom plate 6. The glass oozes through the bosses and forms inverted cones of glass from the vortices of which gravitationally flow filaments 8, 8 which are adapted to be collected by an operator and trained over an applicator y lfl. which is designed to coat each filament with 3 Suitable l; preferably of thermoplastic or thermosetting material. The filaments are then drawn by the operator into a peripheral groove 12 in a gathering sheave 14 which is adapted to associate the filaments 8, 8 into a strand 16 such strand being entered between a pair of opposed drawing rolls or elements generally designated 18, 18. It will be noted that in static condition the drawing rolls are spaced from each other as shown in solid lines and provide an entry gap therebetween whereby the strand may be readily positioned between the rolls.

Each roll 18 comprises preferably a metallic wheel or disc 20 having a hub 22 suitably keyed to a driving shaft 24. The outer edge of the plate 29 is formed with a rim 26 about which is disposed a circumscribing annulus 23 which is formed of yieldable resilient rubberlike material such as soft rubber. The inner periphery of the annulus 28 has a cylindrical contour in complementary fit against the outer face of the associated rim 26 and suitably bonded or vulcanized thereto. Under static conditions, the outer periphery of the annulus 28 is of cylindrical form as shown in solid lines in Figures 1 and 2. The annulus 28 is formed intermediate its inner and outer edges with transverse slots 39, 30 which are regularly spaced and elongated circumferentially of the annulus. Each slot or aperture 30 is defined by a curved outer surface 32 whose center of inscription is eccentric with respect to the axis of rotation of the related drawing member 18 whereby the surface is nonconcentric with respect to the inner and outer peripheries of the annulus. The surface 32 is bowed from its circumferentially spaced ends arcuately outwardly towards the outer periphery 34 of the annulus whereby the radial thickness of the material between the surface 32 and the segment of the surface 34 in radial alignment therewith progressively decreases toward the center of the segment. Each circumferentially spaced end of each surface 30 is formed with a radius which turns inwardly and joins with the adjacent end of the inner surface 36 of the slot, said inner surface 36 being preferably concentric with the inner surface 38 of the annulus. The arrangement of the slot and its elongation circumferentially of the annulus as well as the contour of the slot determines the expansibility of the associated segment 40 of the annulus outwardly thereof. It will be seen as represented by phantom lines that each segment 40 will expand or bulge radially outwardly due to the imposition of a centrifugal force pursuant to rotation of the related member 18 in a manner which develops or distorts the normally cylindrical surface 34 into an undulant or wavy contour. The thinnest portion of each section 40 bulges outwardly the greatest distance, the bulging progressively decreasing as the section becomes thicker toward each of its circumferentially spaced ends and the outward displacement is the least in areas in radial alignment with segments 42 intermediate the slots 30, 30. It will be noted that the opposed members 18, 18 are so arranged and their rotation controlled so that the bulged out segments will mesh with each other at the grasping areas of the rolls and that the centrifugal force and the nature of the material forming the annuli is suflicient to close the gap between the rolls and thereby effect a grasp on the strand while deflecting the strand to conform to the sinuous contour developed between the engaging surfaces. The construction of the slots 30, 30 by the provision of a radius at each end of the surface 32 thereof avoids concentration of stresses which would tend to tear the material and at the same time, the construction is such that the lightest part of each section 40 is caused to efiect maximum deflection of strand whereby a light gentle deflecting action is obtained.

This feature begets a modifying effect in the initial engagement of the lightest mass at crest 43 of each bulge in that it may be moved or flattened inwardly momentarily opposed roll at the grasping region of the rolls.

' corresponding reference numerals.

Referring now to Figures 35, the annulus generally indicated 100 comprises normally cylindrical inner and outer surfaces 102 and 104 as in the previous embodiment'and on its surface'102 is bonded to the rim 26 of the wheel. The annulus 100 is formed of flowable, deformable' flexible rubberlike material such as soft rubber and is provided intermediate its inner and outer peripheries with a plurality of apertures or transverse slots 7 106, 106 which are spaced uniformly and elongated circumferentially of the annulus. .The drawing elements are rotatable as shown by the arrows and each openi'ng is' provided at its leading edge with a baffle 110 which is formed at its opposite sides with circumferentially converging air guide surfaces 112, 112 directed from the respective side edges of the annulus inwardly thereof in the direction opposite to the direction of rotation of the annulus. The trailing edge of each opening 106 is formed with a pocket 114 which is concaved in a direction facing in the direction of rotation of the annulus toward the trailing edge 116 of the baflle 110, the pocket 114 being defined by side walls or webs 128, 120 at opposite sides thereof and diverging o'n'their inner sides in a direction toward the baffle 110. It will be seen that the contour of the radially outer periphery 122 of theslot 106 is curved, the curvature being defined from an axis eccentric with respect to the curvature of the surfaces 102 and 104 of the annulus 100 and so arranged that the midsection 124 of the segment 126 of the annulus outwardly of each slot 106 is substantially thinner radially thanthe adjoining sections which as they approach the opposite ends of the slot. It will be seen that the trailing edge 116 of the baffle 110 is formed with a radius or filet which merges at its outer extremity with the related surface 122 and at its inner extent with the surface 128 of the inner periphery of the slot 106, the surface 128 being'preferably concentric with the surfaces 104 and 102. Similarly the leading edges formed witha radius which merges at its outer end into the surface 122 and at its inner end into the surface 128.

Each end of the surface 122 at opposite sides'of the baflle is also formed with a gentle radius as at 123 (Figure 4) which merges into the opposite ends of surface 128. This construction eliminates concentration of stresses at opposite ends of the slot such as would tend to tear the material and at the same time provides effective air flow characteristics. A radial passage or blower opening 132 has its inner or inlet end open to the pocket 114 and at its outer or outlet end is open through the periphery 104 of the annulus. To extend the area of influence of each blower 132, the outer periphery 104 is formed with a depression 134 elongated transversely of the annulus.

In operation, rotation of the drawing members 13, 18 develops centrifugal force which efiects the expansion of eachannulus 100." It will be noted that the construction of the slots controls the outward bulging of the sections 126 of the annulus so that the mid-section 124 bulges out farther than the adjoining sections which progressively are .displaced closer inwardly to the axis of rotation thereof. This feature develops an undulant or sinusoidal contour of the periphery 104 and the radially outward displacement closes the gap between the opposed ' members 18, 18 whereby at the grasping zone of the rolls,

and with controlled rotation of each roll, the crests of each roll are adapted to'rnate. into the concavities of the progressively thicken radially disposed therebetween and 130 of each side wall 120 of the pocket 114 are m opposed roll which obtains a deflection of the strand efiects intimate contact with the rolls along sinuous surfaces which are arranged to interlock with the strand under relatively light pressure over an extensive length thereof thereby providing the desired grasp on the strand while imposing an attenuating pulling force thereon.

It will be notedthatfthe construction effects maximum deflection of the strand by the sections 124 of the material having the smallest or least mass whereby the deflecting action is gentle and eliminates any possibility of deforming the strand. The construction of the blowers is such as to strip the strand effectively from the gripping surfaces by blowing the strand away therefrom. The disposition of the baffle surfaces 112, 112 directs the air during rotation of the annulus into the trailing pocket 114 which discharges the air through the outlet 132. Referring now to the embodiment shown in Figures 6 to 8, each member 18 is provided'with'an annulus 200 formed of flowable flexible rubberlike material such as soft rubber and statically having concentric inner and outer substantially cylindrical surfaces 202, 204, the surface 202 being secured as by vulcanizing to the rim 26 of the associated member 18. The annulus 200 is formed intermediate'the surfaces 202 and 204 with a series of uniformly circumferentially spaced transverse slits 206, 206 elongated cir'cumferentially of the annulus. Each slit is' terminated at its circumferentially spaced ends tan gentially to a transverse cylindrical aperture 208 which is disposed inwardly of the slot' and designed to eliminate concentration of stresses at the ends. of the slot.

engagement with the strand passing between the opposed members 18, 18 will be relatively delicate. To accentuate stripping of the strand as it leaves the grasping area 'between the members 18, 18 whereat the strand is sinuated between the mating bulged-out areas as in the previous designs, a radial aperture 212 is provided through each segment 210 with an inletopen to the associated slit 206 and the outlet communicating with a transverse elongated depression 214 in the peripheral surface 204.

In operation, the members 18, 18 which are normally spaced apart under static conditions, are rotated which expand, through centrifugal force, their annuli 200, 200. and deform the surfaces 204 thereof to undulant substantially symmetrical generally sinusoidal'contour. The members 18, 18 are controlled in their rotation to mate the bulged-out segments 210 within the concavities between the similarly bulged-out segments of the other roll as may well be seen in the drawings; I The openings 212 serve as peripheral blowers which blow the strand away from the grasping surfaces, the cavities 214 merely serving to widen the outlet area of the openings 212.

It will be observed that in each of these embodiments, the openings or cuts are designed to provide a circumferentially elongated floating section outwardly thereof and that each cut is designed to control the bulging contour in such manner as to achieve. a gentle nondeformative and yielding engagement of the crest of each bulge with the strand. The term rubberlike is used to denote r any substance having characteristics similar to rubber. as to elongation, deformity, yieldability etc.

What. is claimed is: j a 1. A rotatable glass fiber drawing'elementcomprising The curvature of each slot is determined from an axis eccentric a flexible annulus formed of fiowable resilient material having axially spaced sides, said annulus formed with an annular series of perforations therethrough open through the sides and disposed intermediate the inner and outer peripheries of the annulus and elongated circumferentially thereof, a pair of laterally spaced webs at opposite sides of the annulus integral therewith and disposed at one end of each perforation and defining a pocket forming an air scoop facing into the direction of rotation of the element and said annulus formed with passageways from each pocket through the outer periphery of the annulus to efiect a blowing action from the pocket outwardly through the periphery to strip fiber engaged with the periphery.

2. An element according to claim 1 wherein the webs flanking each pocket diverge in the direction of rotation of the element.

3. An element according to claim 1, and said annulus References Cited in the file of this patent UNITED STATES PATENTS 437,208 Kinney Sept. 30, 1890 627,483 Cornly June 27, 1899 906,569 Seiberling Dec. 15, 1908

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