US2989258A

US2989258A - Traversing mechanism

Info

Publication number: US2989258A
Application number: US782700A
Authority: US
Inventors: Lester L Margason
Original assignee: Pittsburgh Plate Glass Co
Current assignee: PPG Industries Inc
Priority date: 1958-12-24
Filing date: 1958-12-24
Publication date: 1961-06-20
Anticipated expiration: 1978-06-20
Also published as: BE585992A

Description

June 20, 1961 1.. MARGASON 2,989,258

TRAVERSING MECHANISM Filed Dec. 24, 1958 2 Sheets-Sheet 1 I no. 4

INVENTOR. zzsrezq A. flAROASO/V HTTOk/VE'Y June 20, 1961 L. 1.. MARGASON 2,989,258

TRAVERSING MECHANISM Filed Dec. 24, 1958 2 Sheets-Sheet 2 INVENTOR. 4: -54 4 mnecnso/v l I t I III nrroklvf) United States Patent 2,989,258 v TRAVERSING MECHANISM Lester L. Margason, Oakmont, Pa., assignor to Pittsburgh Plate Glass Company, Allegheny County, Pa., a corporation of Pennsylvania Filed Dec. 24, 1958, Ser. No. 782,700 4 Claims. (Cl. 242-43) 7 The present invention relates to apparatus for winding a strand of fibers on a tube and it has particular relation to a mechanism for rapidly traversing the strand on a tube While it is being wound at a high rate of speed.

' In the production of continuous filament, textile, glass fibers, 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 wtund in an open wind on a rapidly rotating forming tu e.

There is no twist in the strand as it is thus formed and a binder is applied to the filaments prior to the winding 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. If 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 through a substantial length of the tube for a relatively few turns of the strand on the tube, i.e., 2 to or more turns for a six inch long package for each traverse of the length of the tube. With this type of wind the succeeding turns of the strand cross each other at a minimum angle of at least about 5.

The spiral wire traverse shown in US. Patent No. 2,391,870 has been used for traversing a strand at a very high rate of speed on a forming tube. In operation, the pair of conical spiral, wire cams mounted on the rotating shaft of the traverse cause the strand to be positively moved along the forming tube and returned by the sucrcessive engagement of the strand with the cams. As the strand reaches the end of one cam, its motion is interrupted by it being contacted with the other cam and it is immediately started on its return movement to the other end of the other cam. This change or transfer of the strand from one cam to another has been observed to be quite abrupt, and the strand undergoes a physical beating upon this transfer from one cam to the other. Sometimes the cams become sprung during operation and "the strand is held momentarily at the end of the traverse and then springs back abruptly. The beating and abrupt 'change in direction have caused breakage of some of the filaments. As soon as a few of the filaments become broken, the drawing operation usually is interrupted.

It is an object of the present invention to provide a traverse mechanism for rapidly traversing a strand as it is ,wound at a high rate of speed on a tube which mechanism does not require the transfer of the strand from one cam to another. It is a further object of the invention to provide a traverse mechanism which produces a smooth change in direction of the strand at the end of its traverse without unduly subjecting the strand to a physical beating. It is a further object of the present invention to produce a traverse mechanism which is easy and inexpensive to make, maintain and operate.

Patented June 20, 1961 These and other objects of the invention are accomplished by means of a single wire which is in the shape of an S or .a Z and which is cap-able of being rotated at a high rate of speed. The invention and its method of operation may be more fully understood by reference to the description of the drawing in which:

FIG. 1 is a diagrammatic view of glass fiber forming apparatus including the. traverse mechanism of the present invention;

FIG. 2 is an elevation of the traverse mechanism;

FIG. 3 is an end view of the traverse as shown in FIG. 2;

FIG. 4 is an end view of the traverse mechanism rotated upon its axis from the position of the traverse shown in FIGS. 2 and 3, and

FIGS. 5 to 15 illustrate diagrammatically the movement of the strand 0n the traverse during rotation of the traverse.

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 with a series of orifices in the form of tips 14 through which the molten glass fiows and forms in small cones 15 suspended from the tips of the orifices 14. The tips are usually formed 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 in number. A smaller or greater number of tips may be present in the bushing,

Glass filaments 16. are pulled from the cones 15 at a very high rate of speed, i.e., 5,000 to 20,000 feet per minute, and wound on a rapidly rotating forming tube 18 which may be approximately 6 inches in outside diameter and may rotate at approximately 6850 to 7600 revolutions per minute. The glass filaments are grouped into a strand 19 as they pass over guide 20 prior to their being wound on the tube 18. Usually a liquid binder and lubricant 'such as -a combination of starch and vegetable oil are applied to the filaments in the strand as they pass over a felt pad on the guide, which pad is saturated with the binder and lubricant. The binder and lubricant may be dripped onto the pad by means of an applicator 22.

inch diameter brass rod which has been bent in substantially a single plane in'the form of an S or a Z inter.- mediate itsends. The rod extends generally in an axial direction. with successive portions of the rod being laterally displaced from the axis first on one side of the axis and then on'the other side of the axis. The center of the rod with respect to the mid-point of travel of the strand along the traverse is in the axis of rotation of the rod. The laterally displaced portions should be symmetrical so as to avoid undue vibration of the traverse during rotation. The portions of the traverse which are farthest from the axis may be bent slightly in a smooth curve from the general plane of the traverse, i.e., at 2 to 45, in the direction of rotation of the traverse. This permits the traverse to intercept the strand a little sooner in its travel toward the end of the throw and permits the change in direction to be a little smoother than if the bends were not present.

The rod or shaft is connected to a motor 29 which is mounted on a movable base 30. The axis of the rod 26 is parallel to the axis of the tube 18. The traverse 24 is located adjacent tube 18 so as to cause the strand 19 to curve around the traverse 24 at all times in its travel from the guide to the tube. In other words, the axis of the traverse is olfset laterally several inches A from a line drawn from the guide to the periphery of the tube 24 where the strand first contacts the tube so that it is more in line with the guide and the axis of the tube 18. The traverse 24 may be made to reciprocate in the direction of its axis by moving it, the motor 29 and the movable base 30 on which the motor is attached by means of a reversible motor 32 which is attached to the base to cause the base to move in slideway 34. The traverse 24 may be maintained in a stationary position while it rotates and the tube 18 may instead be reciprocated axially.

The position of the traverse 24 with respect to the tube 18 and also the position of the strand 19 on the traverse during its travel between the guide and the tube are illustrated in FIGS. 3 and 4. FIGS. 2 and 3 show the strand at the mid-point of its travel on the traverse and when the traverse is not rotating. This is at a time when the general plane of the traverse is substantially parallel to a straight line between the guide and the tube. When the general plane of the traverse is substantially parallel to the travel of the strand during rotation of the traverse, the strand will be at one end or the other of the traverse. It can be seen from FIGS. 3 and 4 that the traverse 24 is always placed with respect to the guide 20 and tube 18 so that the strand is slightly displaced and there is tension on the strand which causes it to move against the traverse.

The movement of the strand with respect to the traverse while it is rotating is illustrated by the series of positions of the traverse shown in FIGS. 5 to 15. These figures are diagrammatic views looking in a direction along the line of travel of the strand from the guide to the traverse. Since the strand is always under tension, it will tend to move along the length of the rod 26 to the point where there is the least amount of tension. Thus, assuming that FIG. 5 represents the traverse at rest, the strand 19 will be at the center point 35 of the traverse or the point where the rod 26 passes through the axis of the traverse. As the rod rotates, as shown in FIG. 6, the strand will move to the left towards the depression 36 in the rod which is removed from the axis because the strand is seeking the path of least resistance. This travel is continued in FIG. 7 where the rod has rotated through approximately 90. As the rod continues to rotate past 90 to 135, as shown in FIG. 8, the tension on the strand begins to increase and this slows down the sidewise travel of the strand. The bend of the outermost portion of the depression 36 into the direction of rotation causes this slowdown to begin before the strand gets to the end of the depression and makes the change in direction smoother. The travel of the strand to the left ceases as the rod has rotated approximately 180 as shown in FIG. 9.

As the rod rotates past 180 to 225, the strand begins to move to the right to a point of lesser tension, as shown in FIG. 10, and will move across the center point 35 of the rod as shown in FIG. 11 to seek the depression 38 in the rod which is on the other side of the center point 35 of the traverse. In FIG. 12 the rod has rotated through 315, and the strand is beginning to slow down in its travel to the right. In FIG. 13 the rod has rotated 360 and the strand 19 has been stopped in its movement to the right and is ready to begin or has begun its return travel to the left as shown in FIG. 14. In FIG. 15, the strand 19 is approaching the center point 35 in movement along the length of the traverse toward the left again. This cycle is repeated over and over again during the rotation of the traverse. The tension on the strand is the driving force which causes the strand to move laterally along the rod. This is in contrast to the traverses of the prior art which have positively displaced the strand.

The length of throw or traverse of the strand can be controlled by the amount of tension which is put on the strand by the placement of the traverse with respect to the tube 18 and guide 20. The more tension that is 4 applied, the greater is the length of throw and conversely the less tension that is applied, the smaller is the length of throw. The angle a at which the central portion of the rod crosses the center point 35 or axis of the traverse also determines the length of throw of the traverse, the greater the angle, the faster the strand 19 tends to move away from the center point 35 of the traverse to the right or left depending upon which is the path of least resistance. The rate of rotation of the traverse also affects the length of throw, the higher the rate of rotation, the shorter the length of throw. The combina tion of the tension caused by displacement of the traverse against the path of the strand and the angle of crossing of the rod 26 with respect to the axis of the traverse should not be so great that the strand 19 is thrown past the outermost points of the

depressions

36 and 38 of the traverse. In this event, the strand will dwell outside the end of the traverse. If it dwells outside the end of the traverse closest to the motor, it will probably break. If it dwells outside the end away from the motor, it will probably come back onto the traverse, but the package build-up will be non-uniform. The axial distance 1" between these outermost points should be greater than the length of throw desired.

The following conditions are exemplary of the operation of the traverse in the formation of glass fibers. The strand 19 may be traveling at a speed of 11,000 to 13,000 feet per minute and the distance between the guide 20 and the tube 18 may be approximately 25 to inches. The traverse 24 will be located as close to the tube 18 as possible without contacting the package of strand on the tube. This gives best control of the lay of the strand on the package. The traverse 24 may be offset perpendicularly from a line drawn from the guide to the surface of the forming tube by about 1 to 3 inches. The traverse may rotate at about 1800 to 1900 revolutions per minute and reciprocate axially 6 times a minute. The outermost points of the depressions in the rod 26 may be 1 to 2 or more inches in a perpendicular distance d from the axis and they may be 3 /2 to 5 or more inches apart in an axial distance t. The angle which the central portion of the rod 26 forms with the axis of the traverse may be about 45, but may vary widely, for example by about 20 to 70. These conditions are suitable for traversing the strand approximately 1 /2 to 2 /2 inches on the tube during rotation of the tube. The traverse of the present invention can be employed in the apparatuses shown in the copending applications of Franklin H. Green, Serial No. 782,417 filed December 23, 1958 entitled Fiber Forming Apparatus and Serial No. 782,429 filed December 23, 1958 entitled Apparatus for Forming Fibers.

It can be seen that if the rod is rotating in the neighborhood of 1800 to 1900 revolutions per minute, the strand will move back and forth over the rod quite rapidly. The use of the curved rod or wire as a traverse mechanism permits the change in direction of traverse of the strand to be accomplished very smoothly and greatly minimizes the physical beating which the strand under" goes in the prior art devices. The traverse mechanism of the present invention is simple and inexpensive to make, maintain and repair. Slight variations in the symmetry of the curvature of the offset portions in the rod can be tolerated and a uniform package can be produced.

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

I claim:

1. An apparatus for traversing a strand of fibers while it is being wound on a tube which comprises a rod having a portion of its length intermediate the ends curved in substantially the form of a Z and means for axially rotating the rod.

2. An apparatus for traversing a strand of fibers as it is being wound on a tube which comprises a rod having symmetrical portions intermediate its ends which are alternately and oppositely, laterally displaced from the general axis of the rod and means 'for axially rotating the rod.

3. An apparatus for traversing a strand of fibers while it is being wound on a tube which comprises a rod extending generally in an axial direction with successive portions of the rod being laterally offset from the axis on first one side of the axis and then on the other side of the axis and means for axially rotating the rod.

4. An apparatus for traversing a strand of fibers while it is being Wound on a tube which comprises a rod extending generally in an axial direction with successive portions of the rod being laterally and oppositely otfset 6 I from the axis on first one side of the axis and then on the other side of the axis and with the outermost section of each of the oifset portions being curved in the direction of rotation of the rod, and means for axially rotating the rod.

References Cited in the file of this patent UNITED STATES PATENTS 1,990,620 Schweiter Feb. 12, 1935 2,433,304 Stream Dec. 23, 1947 FOREIGN PATENTS 454,062 Great Britain Sept. 23, 1936 691,328 Great Britain May 13, 1953 209,963 Switzerland Aug. 16, 1940