US3041664A - Apparatus for forming fibers - Google Patents

Description

i 1952 F. H. GREEN I 3,041,664

APPARATUS FOR FORMING FIBERS INVENTOR. FRANKLIN 6! Off! A Trap/vi) United States Patent 3,041,664 APPARATUS FOR FOG FERS Franklin H. Green, Shelbyville, 1nd, assignor to Pittsburgh Plate Glass Company, Allegheny County, Pa., a corporation of Pennsylvania Filed Dec. 23, 1958, Ser. No. 782,429 3 Claims. (Cl. 18-8) The present invention relates to apparatus for winding fibers on a tube, and it has particular relation to an improvement in a process of forming glass fibers by drawing them from a molten supply of glass and winding the fibers at a high rate of speed on a forming tube.

A process for forming continuous filament textile glass fibers is shown and described in US. Patent No. 2,391,870. In this process a number of glass filaments are drawn from a molten supply of glass at a high rate of speed, i.e., 5,000 to 20,000 feet per minute. The glass passes through orifices in a bushing and forms cones of glass at the tips of the orifices. The individual filaments are drawn from the cones of glass and are grouped together into a strand as they pass over a guide. The strand is thereafter wound in an open wind on a rapidly rotating forming tube.

There is no twist in the'strand as it is thus formed and a binder is applied to the filaments prior to thewinding of the strand on the tube in order to bond them together and maintain the integrity of the strand. An open wind, rather than a parallel, level wind, is desired on the forming tube in order to aid removal of the strand from the tube. It a parallel, level wind is used, the untwisted strand is very difficult to remove when the filaments become broken. In this event, successive turns of the strand become entangled and it soon becomes impossible to unwind the strand and remove it from the tube. The open wind is such that the strand is traversed the length of the tube for a relatively few turns of strand on the tube, i.e., 2 to 5 or more turns for a 7 to 10 inch long packages for each traverse of the length of the tube. With this type of wind .the succeeding turns of strand cross each other at a minimum angle of at least 5.

The spiral wire traverse shown in US. Patent No. 2,391,870 has proved to be satisfactory for traversing a strand at the very high rate of speed which is employed to wind the strand on a forming tube. This traverse, in addition to rotating about its own axis, is reciprocated axially in order to distribute the strand over the length of the tube. This type of traverse requires that there be a certain minimum tension on the strand as it passes over the cams of the traverse to hold it on the cams as they tend to push the strand toward either end of the forming tube. There is a natural tendency for the strand to return to the center of the forming tube, and there is a minimum tension which is required to overcome this tendency and maintain the strand at its proper position on the cam to produce the desired open wind. If this tension becomes too great, there is the problem of the individual filaments of the strand breaking at the gathering guide due to too much friction as they pass over the guide. As soon as one filament breaks, the whole strand usually breaks.

This problem of tension on the strand has become aggravated by a desire to have the glass fiber process performed all on one floor; whereas, it has been previously conducted on two floors. In the prior process, the bush- 7 3,041,664 Patented July 3, 1962 ing and forming tube were so far apart that the bushing and guide were located on one floor and the forming tube and traverse on a floor below. The two-floor process was believed to be necessary in order to provide the proper angles to the fibers as they pass from the bushing over the guide and onto the forming tube. The prior process has required a man on each floor to operate it. It is now desired to conduct the fiber-forming process on one floor with the bushing and forming tube closer together so that one man can operate the process. This latter arrangement imposes more severe angles and tension conditions on the process.

It is an object of the invention to produce glass fiber strand according to the above-described process with a minimum distance between the bushing and forming tube. It is a further object of the invention to produce long packages of glass fiber strand on a forming tube. It is desired to achieve these objects while imposing a minimum amount of tension on the strand during the fiberfcrming process. The manner of accomplishment of these and other objects will be apparent from the description of the drawing in which: I FIG. 1 is a diagrammatic view of the apparatus of the invention illustrating the variables in the process, and

FIG. 2 is a side view of FIG. 1. v In FIG. 1 of the drawing, there is shown a glass melting furnace or forehearth thereof 10 containing a supply of molten glass 11 and having a bushing 13 attached to the bottom of the furnace. The bushing is provided witht a series'of orifices in the form or" tips 14 through which the molten glass flows and forms in small cones 15 suspended from the tips of the orifices 14. The tips are usuallyformed in a number of rows, for example, 4 to 6 or more rows having a great many tips in each row so that the total number of tips is about 204 or 408 in number. A smaller or greater number of tips may be present in the bushing.

Glass filaments 16 are pulled from the cones 15 of glass at a very high rate of speed, i.e., 5,000 to 20,000 feet per minute, and woundv on a rapidly rotating forming tube 17 which may be approximately 6 to 7 inches in outside diameter. The tube may be rotated at approximately 2,000 to 10,000 rpm. by a motor 18 which is As the strand 19 is wound on the tube 17, it is rapidly traversed in open wind along the length of the tube by means of the traverse 24-. The traverse is composed of a shaft or spindle 26 having a pair of complementary, conical, spirally disposed, wire cams 27 mounted on the shaft 26. The shaft is caused to rotate at 1,000 to 2,500 rpm. by a motor 29 which is mounted on a base 30.- The axis of the shaft26 is parallel to the axis of the tube 17. The

traverse 24 is located adjacent tube 17 at a point Where it intersects the strand as it travels from the guide to the periphery of the tube 17. The traverse 2.4 is made to reciprocate in the direction of its axis by moving the base.

30 in slideway 32 by suitable means such eating motor 34 which is attached to the base.

as a recipro- The guide is normally located directly beneath the center of the bushing 13. This is to maintain the angle which is the angle between the outside filament and a vertical line from the cone from which the outside filament is drawn, to a minimum. The forming tube must be offset from a vertical line drawn from the bushing through the guide by an angle 5, which is the angle between the vertical line and aline drawn from the guide to the periphery. of, the; tube upon which this strand is wound. The: angled must always be slightly larger than the angle; a. inorder to hold the outside filament; it? in the; groove. or onythe pad: on'. the guide 20. The angle ,8 is rapidly. andregularly increasedin slight amount by the height of'the cams 27-on the; traverse as the strand is moved'back and forth. over the cams.

Another angle which must be considered in the relative positioningot the guide, traverse and forming tubeis the ai1gle.:which is formedbya line drawn from the guide to the center of the strand-package on the tube and a line drawn from the guideto the'end of, the strand package ontlie tube. The angle is'in a plane which is at an 1 angle to the plane in which the angles a and fi are'located.

TheainounLof tension on the strand is determined by the angles a, B and 5. The angle a is determined by the width w of; the'bushingl andrthe distancea between I theibushing 13-and the guide 20.? As: wisfmade greater and/ or a is made smaller, or becomes greater. In the prior art process the distance a has'beenof the order of 40' inchesnand the distance w has been of the order of 4 to 12 As the angle at becomes greater, angle '6 must inches. become greater because as said above, 5 must'always be slightly greater. than afinorder to keep outside'filament 40 onthepadandguide.

1 Angle Bis also a ffectcd by the distance b and angle o.

The distance I) is the distance between the guide and the forming tube and in theprior art has been of the order of 80 inches or roughly twice as great as the distance a. As 5 becomessmaller, becomes greater for a given width of traverse't on the tube. The strand moves backand forth on the traverse as the traverse rotates. As shown in US; 2,391,870, the traverse itself moves back and forth in a'path: parallel to the axis of the tube. As 'angleebecomes greater, there is' a greater tendency-tor the strand during its traverse to want to. returnto-the center line running from the guide to the center" of the package on.

the tube, and it is more difiipultfto keepth strand at the proper point on the wire camof the traverse as it rotates.

Inordertokee'p the strand at the proper point on the traverse, especially at the extremes of traverse, it is necessary to increase the tension on the strand between the guide and the tube; angle ,8.

In order to convert this process from a two-floor to a one-floor process, it can be seen thatthe distances a and b must be reduced and it is proposed that they be reduced to the point where they are each about and inches respectively. It is also desired to increase the width w of the bushing in order to increase the number of orifices and filaments which are produced from one bushing. 'It is further desired to improvet-he process by.

mits the angled to be at a minimum and therebypermits This is done iucreasinlg the t the process described in the patent. This modification'per in coordination with the reciprocation of the traverse 24;

As the traverse moves to one end of the package; the

guide moves in that direction also and as the traverse returns to the center and moves to the other end of the package, the guide moves in that direction also. The guide moves approximately the same distance as the traverse during these regular and continuous reciprocations. This may be accomplished by mounting the guide 20 on frame elements 4-2 and 4 4 which are rigidly connected to the base 32 on which the traverse 24 and motor 29 therefor are mounted. As the base moves in and out to reciprocate the traverse, the guide 20 also reciprocates through the. samedistance.

The reciprocation of the guide 20iwith the traverse reduces the'angle to the minimum which is required by the distance of throw created by the traverse in order to produce the minimum angle of crossing of'the strand for the open wind on the package. The angle is thereby maintained at its minimum, and angle 5 may also be maintained at its minimum. By reason of the reciprocation of the guide, longer packages canbe made with less tension on the strand than previously required. The reduced amounnt of tension has also: permitted the distances a and b to be reduced and allow the fiber-forming operation to be performed on one floor and'handlcd by a single operator,

The'followingconditions of operation of the apparatus of the invention are ,given by way of example. The strand l9 travels at a. speed of 12,000 feet per minute and is wound on the periphery of a forming tube 17 having a diameter of about 6%. inches and rotating; at about 7,000 revolutions per minute. The traverse Zl rotates at a speed of about 2,000 revolutions per minute and traverses the strand on the tube through a distance of about 2 /2 to 5 inches for each half revolution. The traverse 24 and guide 20 reciprocate back and forth over the length of the tube once every 10 seconds.

Although the invention has been described with. respect to specific details of certain embodiments thereof, it is not intended that such details be considered as limitations upon the scope of the invention except insofar as set forth in the accompanying claims.

I claim:

1. An apparatus for forming glass fibers which comprises a stationary container for a supply of molten glass,

a bushingin the bottomof the container and means for the tube, a rotatable traverse mounted adjacent the tubefor distributing the'strand on the tube in an open wind,

means for rotating the traverse, means for reciprocating. the traverse-in a path which is parallel to the axis of the tube and means for reciprocating the guide in a line parallelto thezaxis of the tube and in coordination with.

tube'for winding the strand thereon, means for rotating the tube, a rotatable traverse for distributing the. strandv on the tube in an openwind composed of a shaft rotating on an axis parallel-to the axis of the tube, a pair of' independent complementary cams mounted on the.

. shaft for engaging the strand and moving it longitudi- -the angle BIto'be at its minimum which'isrequired to keepthe'outsidefilamentdd on the guide; This is'accomplished by causing the guide Zllto'reciprocate in av pathv which is parallel to'the axis of the traverse 24 and nally ofthe tubein a reciprocating manner as the traverse rotates, means for rotating the'traverse, means forrecip rocating the traverse in a path which is parallel to the axis of the tube andfmeans for reciprocating the guide in a linevparallel tothe axis ofthetube and in coordination with the reciprocation of the traverse.

spams;

3. An apparatus for forming glass fibers which comprises a container for a supply of molten glass, a bushing in the bottom of the container and means for drawing glass filaments from the bushing including a guide for grouping the filaments into a strand, a rotatable tube for Winding the strand thereon, means for rotating the tube, a traverse mounted adjacent the tube for distributing the strand on the tube in an open wind, means for reciprocating the traverse in a path Which is parallel to the axis of the tube and means for reciprocating the guide in a line parallel to the axis of the tube and in coordination with the reciprocation of the traverse.

References Cited in the file of this patent UNITED STATES PATENTS Van der Waals June 22, 1937 Moncriefi et a1. Mar. 21, 1939 Simison Feb. 10, 1942 Auwarter et a1. June 29, 1943 Beach Jan. 1, 1946 Pim et a1. Sept. 22, 1959 FOREIGN PATENTS 7 Great Britain Oct. 23, 19-13

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