Winding – tensioning – or guiding – Tension control or brake – Supply controlled
Reexamination Certificate
2000-06-08
2002-04-23
Mansen, Michael R. (Department: 3653)
Winding, tensioning, or guiding
Tension control or brake
Supply controlled
C028S187000, C028S212000, C073S862473
Reexamination Certificate
active
06375111
ABSTRACT:
BACKGROUND
1. Field of the Invention
The present invention relates to the field of beaming of elastomeric yarn by unwinding the yarn from cakes in a creel and winding, or beaming, the elastomeric yarn onto a beam in a beaming apparatus.
2. Description of the Related Art
Elastomeric yarn is made by spinning yarn and winding the spun yarn onto a tube to form a cake of elastomeric yarn. Manufacturers of fabrics that include elastomeric yarn require a large number of ends of yarn in order use the yarn in machines to make a fabric, and therefore it is necessary to wind, or warp, a large number of ends from cakes onto a beam to knit or weave the elastomeric yarn into warp-stretch fabrics.
Machines for warping elastomeric yarn are known in the art. Turning to
FIG. 1
, there is shown a conventional beaming apparatus
11
that include a creel
13
, a pre-stretch unit
15
, and a warper head
17
. Elastomeric yarn is unwound from a large number of cakes
19
in creel
13
where pre-stretch unit
15
produces the pulling force necessary to unwind the yarn from the cakes. The yarn is wound onto a beam in warper head
17
.
Creel
13
includes a plurality of cakes, usually from 1000 to 1600. As shown in
FIG. 2
, cakes
19
have a central core, or tube,
21
around which elastomeric yarn
23
is wound. Typically, creel
13
includes at least one frame with cakes
19
mounted on each frame in long horizontal or vertical rows and in a number of levels or stories above one another. Creel
13
often includes more than one frame in which case the frames are spaced apart either parallel to each other or in some other configuration. Each cake
19
is mounted on a rotatable spool or drive roll and the outer circumferential surface of cake
19
, that is, elastomeric yarn
23
, is placed in contact with a drive roll
25
that drives the surface of cake
19
in a speed ratio of 1:1 to unwind cake
19
. While being unwound, yarn
23
is also subject to a pulling force from pre-stretch unit
15
.
Pre-stretch unit
15
includes rolls
27
which pull yarn
23
from creel
13
at a pulling force necessary to assure optimal unwinding of yarn
23
. If the pulling force is too high or too low, yarn
23
will unwind incorrectly.
Yarn
23
, as it is unwound, typically passes through a thread guide
31
which orients yarn
23
approximately 90 degrees toward pre-stretch unit
15
. Thread guide
31
is generally in the shape of a loop called a pigtail, and is made from ceramic.
As yarn
23
exits creel
13
, unwound yarn
23
from one level or row of cakes
19
passes through a front guide
33
to orient yarns
23
into a thread sheet. As the threadsheet enters pre-stretch unit
15
, yarn
23
is aligned by a separation comb
35
before passing onto rollers
27
.
Yarn
23
passes from pre-stretch unit
15
through a reed
37
and then to beam
29
. Reed
37
is a comb-like structure that has a base and a plurality of needles connected to the base so as to define spaces therebetween through which the each of yarns
23
from creel
13
are threaded.
A conventional beaming apparatus as described above typically operates at unwinding speeds of about 170 meters per minute, depending on the yarn. As will be explained in greater detail below, there are inherent problems with such conventional beaming apparatuses which are solved by the present invention.
SUMMARY OF THE INVENTION
The inventive apparatus includes the following features: a rotating guide, an elastomeric yarn unwinder assembly that includes a guide support that supports rotating guides and a movable buggy for transporting wound cakes of elastomeric yarn to the guide support, a metal thread guide, a front guide and tension bar assembly and a pivoting reed.
The inventive rotating guide for unwinding elastomeric yarn from a stationary cake of wound elastomeric yarn includes a disk, a connector portion formed in the disk to allow the disk to be connected to means for rotating the disk, an aperture formed in the surface of the disk between the connector portion and the outer edge of the disk to allow elastomeric yarn to pass therethrough as the disk is rotated and elastomeric yarn is unwound from the cake, and means in the aperture for controlling the pulling force on an elastomeric yarn pulled through the aperture so that if the elastomeric yarn is unwinding freely from the cake the pulling force is decreased and if the elastomeric yarn is not unwinding freely from the cake the pulling force is increased. In one embodiment the pulling force control means includes a top ring, middle ring and bottom ring stacked together in the aperture, each of the rings having an opening formed therein, the middle ring having a projection formed therein that extends into the opening thereof so as to partially cover the openings in the top and bottom rings and that extends in a direction away from the direction of rotation of the rotating guide, wherein the width of the middle ring around the perimeter of the opening formed therein is less than or equal to the width of the corresponding portions of the top and bottom rings.
The invention also relates to an elastomeric yarn unwinder assembly which includes a rotating guide having a disk, a connector portion formed in the disk to allow the disk to be connected to means for rotating the disk, and an aperture formed in the surface of the disk between the connector portion and the outer edge of the disk to allow elastomeric yarn to pass therethrough as the disk is rotated and elastomeric yarn is unwound from the cake, means for rotating the rotating guide attached to the connector portion, and a stationary cake of elastomeric yarn positioned adjacent to the rotating guide. The rotating guide of the unwinder assembly may also include means in the aperture as described above for controlling the pulling force on an elastomeric yarn pulled through the aperture so that if the elastomeric yarn is unwinding freely from the cake the pulling force is decreased and if the elastomeric yarn is not unwinding freely from the cake the pulling force is increased.
The elastomeric yarn unwinder assembly may also include a guide support having at least one arm extending outwardly therefrom, the means for rotating a rotating guide being attached to the arm so as to support the rotating means and the rotating guide on the guide support, and a tray supported on the guide support and positioned below the rotating guide so as to support a stationary cake of elastomeric yarn below the rotating guide. The assembly may also include a movable buggy adapted to mate to the guide support having at least one arm formed therein which extends outwardly therefrom, the stationary cake of elastomeric yarn being supported on the buggy arm such that when the buggy is mated to the guide support the stationary cake of elastomeric yarn is supported below the rotating guide.
Another feature of the invention is a thread guide assembly for use in a beaming apparatus which includes a thread guide having a top portion and a bottom portion, the top portion having a loop formed therein to hold a thread of yarn, a base member attached to the bottom portion of the thread guide so that the top portion of the thread guide may be moved under tension, and means in the base member for detecting an increase in tension on the thread guide so that the tension detecting means provides an indication if the tension on the thread guide exceeds a predetermined amount.
Still another feature of the invention is a thread guide for use in a beaming apparatus, which guide has a loop formed therein to hold a thread of yarn, wherein the thread guide includes a surface-hardened metal.
Another feature of the invention is a front guide and tension bar assembly for use in a beaming apparatus which includes a bar having a plurality of guides formed therein for allowing yarn to be threaded therethrough, and means connected to the bar for measuring the pressure on the bar caused by the force of yarn on the bar as yarn is pulled through the guides in the bar. The assembly may also include output means for rec
Brouwers Johannes Leonardus Jozefus
Groot Frederick Jan
Mycielski Jacek Zygmunt
Van Den Hoven Gerardus
E. I. du Pont de Nemours and Company
Mansen Michael R.
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