Winding – tensioning – or guiding – Helical or random winding of material – Distributing material along the package
Reexamination Certificate
2000-03-21
2003-05-27
Mansen, Michael R. (Department: 3654)
Winding, tensioning, or guiding
Helical or random winding of material
Distributing material along the package
C242S477400
Reexamination Certificate
active
06568623
ABSTRACT:
TECHNICAL FIELD
This invention relates to the production of glass fibers, and in particular, to winding a glass fiber strand to form packages. More particularly, this invention relates to controlling the cam speed for optimum winding angles during package buildup.
BACKGROUND OF THE INVENTION
Mineral fibers are used in a variety of products. The fibers can be used as reinforcements in products such as plastic matrices, reinforced paper and tape, and woven products. During the fiber forming and collecting process numerous fibers are bundled together as a stand. Several strands can be gathered together to form a roving used to reinforce a plastic matrix to provide structural support to products such as molded plastic products. The strands can also be woven to form a fabric, or can be collected in a random pattern as a fabric. The individual strands are formed from a collection of glass fibers, or can be comprised of fibers of other materials such as other mineral materials or organic polymer materials. A protective coating, or size, is applied to the fibers which allows them to move past each other without breaking when the fibers are collected to form a single strand. The size also improves the bond between the strands and the plastic matrix. The size may also include bonding agents which allow the fibers to stick together, thereby forming an integral strand.
Typically, continuous fibers, such as glass fibers, are mechanically pulled from a feeder of molten glass. The feeder has a bottom plate, or bushing, which has anywhere from 200 to 10,000 orifices. In the forming process, the strand is wound around a rotating drum, or collet, to form, or build, a package. The completed package consists of a single long strand. It is preferable that the package be wound in a manner which enables the strand to be easily unwound, or paid out. It has been found that a winding pattern consisting of a series of helical courses laid on the collet builds a package which can easily be paid out. Such a helical pattern prevents adjacent loops or wraps of strand from fusing together should the strand be still wet from the application of the size material. The helical courses are wound around the collet as the package begins to build. Successive courses are laid on the outer surface of the package, continually increasing the package diameter, until the winding is completed and the package is removed from the collet. The waywind is the number of rotations of the collet during the traverse of the cam follower and guide eye from one end of the package to the other (usually a number between 2 and 4).
A strand reciprocator guides the strand longitudinally back and forth across the outer surface of the package to lay each successive course. A known strand reciprocator is the spiral wire type strand oscillator. It consists of a rotating shaft containing two outboard wires approximating a spiral configuration. The spiral wires strike the advancing strand and direct it back and forth along the outer surface of the package. The shaft is also moved longitudinally so that the rotating spiral wires are traversed across the package surface to lay the strand on the package surface. While building the package, the spiral wire strand oscillator does not contact the package surface. Although the spiral wire strand oscillator produces a package that can be easily paid out, the package does not have square edges.
A known strand reciprocator which produces square edged, cylindrical packages includes a cam having a helical groove, a cam follower which is disposed within the groove and a strand guide attached to the cam follower. As the cam is rotated, the cam follower and strand guide move the strand longitudinally back and forth across the outer surface of the rotating package to lay each successive course. A rotatable cylindrical member, or roller bail, contacts the outer surface of the package as it is being built to hold the strand laid in the latest course in place at the package edges as the strand guide changes direction. The roller bail is mounted for rotation, and bearings are used to reduce the friction between the roller bail and the mounting surface. The collet and package are rotating at high speeds during winding. The contact between the roller bail and the rotating package surface causes the roller bail to rotate, and the speed of the roller bail surface is generally equal to the high rotational speed of the package surface. The roller bail has a fixed diameter which is generally less than the diameter of the collet, and may be only 10% of the collet diameter. Therefore, the roller .bail must rotate at higher revolutions per minute (RPMs) to keep the roller bail surface traveling at the same speed as the speed of the package surface. To operate effectively throughout the preferred range of package sizes and preferred collet speeds during winding the roller bail may have to rotate at 70,000 RPMs or higher.
Prior to the advent of digital waywind, the rotation of the collet and the cam were tied together by a belt so that as the collet slowed down (because as the package was built it got larger) the cam would also slow down by a corresponding amount.
Several attempts have been made to control the cam speed during package buildup. For example, U.S. Pat. No. 4,667,889 to Gerhartz discloses a yarn winding process having a traversing yarn guide. The oscillation speed of the guide is proportional to the rotational speed of the package to accommodate the increasing size of the package for a relatively constant wind angle. The speed of the traversing yarn guide rapidly increases at the beginning of various sequential steps to produce a stepped precision wind. The speed can be varied to provide deviations to avoid formation of undesirable patterns.
U.S. Pat. No. 5,056,724 to Prodi et al. discloses a winder having a computer controlled winding program generating continuous winding signals that control the rotation speed of the cam. The windings are kept within a set distance of winding ratio values that are established to avoid undesirable ribboning.
U.S. Pat. No. 5,447,277 to Schliter et al. discloses a stepwise high precision winding method in which the yarn guide reciprocation frequency is reduced as the package is built to accommodate the higher circumference of the bigger package. Each of the steps of the Schliiter process involves reducing the yarn guide reciprocation frequency during the step, but at the beginning of the next step increasing the frequency of reciprocation to a new initial frequency.
In U.S. Pat. No. 4,296,889 to Martens, a random number sequence is used to constantly vary the cam speed to avoid undesirable pattern formations.
However, it is known that some waywinds are not suitable for stable packages. Thus, it would be desirable to avoid the undesirable waywinds to enable the first laid material on the collet to be wound at acceptable waywinds even when the strand is laid down at relatively large wind angles. It is also desirable to allow the cam speed to be slowed down during the beginning stages of the package buildup, thereby allowing the beginning material to be acceptable to the customer and avoiding the need for the manufacturer to remove and scrap the beginning material before shipping the package.
SUMMARY OF THE INVENTION
This invention relates to a method of winding a fibrous strand to build a package. The method includes providing a moving strand, rotating a collet at a rotational speed to wind the strand and build a package, and rotating a cam at a rotational speed to reciprocate the strand with a strand reciprocator to lay the strand at a wind angle on the package surface as the package rotates. The strand is laid on the package surface by varying the relative rotational speed of the collet and the cam as a function of package buildup time while the wind angle remains substantially constant as a function of package buildup time.
According to this invention, there is also provided a method for winding a fibrous strand to build a package including the steps of providing a moving strand,
Adcock Joseph Anthony
Galloway Eugene V.
Mann Douglas Brian
Scarsella Donald
Dottavio James J.
Eckert Inger H.
Mansen Michael R.
Owens--Corning Fiberglas Technology, Inc.
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