Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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TEXTURED SURFACE EFFECT
FABRIC AND METHODS OF MANUFACTURE
TECHNICAL FIELD
The present invention relates to tufted pile fabrics and methods of
manufacturing such fabrics and particularly relates to a tufted pile fabric
affording novel and improved patterns and textures for surface effects
and methods of manufacture.
BACKGROUND
As well known, tufted fabrics are those fabrics in which a plurality of pile
yarns are pushed or stitched through a primary backing or substrate
forming loops which comprise the fabric surface or which loops may be
cut to form a cut pile fabric surface. Machinery for forming these tufted
fabrics is likewise well known. In machinery of this type, one or more
needle bars having a plurality of needles threaded with individual yarns
are reciprocated, typically vertically, to pass the needles through the
substrate to form loops which can remain as the fabric surface or be
subsequently cut to form cut pile. The yarns are fed to the needle bars
from yarn supply creels by one or more feed rolls. Where straight
stitches are formed in the warp direction and the needle bar or bars are
not shifted in the weft direction, the yarn feed rolls are typically controlled
to provide a constant yarn feed to the needles. With a weftwise shift in
the one or more of the needle bars, the yarn feed rolls are controlled to
provide more or less yarn to the needles so that a smooth face of
constant pile height relative to the substrate is maintained on the fabric
surface.
In certain tufting machines, the feed rolls which control the yarn
feed to the needles of the needle bar or bars are driven by servomotors
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which allow different lengths of yarn to be fed to the needles upon
shifting the needle bar or bars. That is, when a needle bar shifts so that
the needles are aligned with different hooks or loopers there is
insufficient yarn fed to the needles to preclude a chop or low line from
appearing across the face of the fabric. To preclude this and to provide
a smooth face across the fabric surface, a variation in yarn feed is
adjusted by adjusting the servomotors driving the feed rolls to
compensate for the extra yarn required to accommodate the weftwise
movement of the needle bar. Thus. to avoid robbing previous tufts or
stitches of yarn due to insufficient yarn feed to the next tuft or stitchl the
servomotor controlled feed rolls in the past have been designed,
programmed and utilized to provide the yarn feed compensation
necessary to create a smooth face in the resulting fabric. That is to say.
feed rolls for controlling yarn feed to the tufting needles have heretofore
been driven by servomotors to allow different or preselected lengths of
yarn to be fed to the needles when the needle bar or bars are shifted to
new hook or looper positions, to enable the resulting fabric surface to
remain smooth and level.
Further, tufted fabrics, i.e., fabrics having tufts of different heights
throughout the fabric, have been provided in the past, for example, in
carpets. Various techniques have been previously employed to provide
tufted piles of such different heights. For example, cam disks have been
used for varying the height of individual tufts in a stitch row in the weft
direction. As the cam disks rotate, the yarn feed tension changes and
differences in pile height are thus created. Roll pattern attachmentsl
pattern slats and control scrolls have similarly been used to vary pattern
height. However, in none of these prior tufting arrangements, has
precise and accurate control of the height of each tuft been achieved in
such manner that the difference in height between next-adjacent tufts in
one or more stitch rows in the warp direction can be greater than 3/32
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inch (2.38 mm). That is to say, with prior mechanisms, the variation in
tuft height from one tuft to a succeeding tuft in the same stitch row in the
warp direction has not exceeded 3/32 inch (2.38 mm). Where a jump in
height of next-adjacent tufts in a warpwise stitch row in excess of 3/32
inch (2.38 mm) was required, the resulting fabric necessarily, because of
the type of tufting apparatus used, had tufts of an intermediate height
intervening between the tufts of the desired heights. That is, the
incremental height adjustment of warpwise immediately next-adjacent
tufts was limited in prior machines to 3/32 inch (2.38 mm) or less in the
fabric. hence limiting the nature of the pattern in the fabric. These
intermediate tufts produced an undesirabie tapering effect in the tufts
albeit the fabric was patterned with warpwise non-next-adjacent tufts
ultimately having a height differential in excess of 3/32 inch (2.38 mm).
DISCLOSURE OF THE INVENTION
In accordance with the present invention, unique patterns and
textures providing novel and improved visual effects are achieved by
utilizing a yarn feed control in a tufting apparatus to intentionally
accurately and precisely create high and low areas in the tufted pile
surface. The surface effects are enhanced and accentuated when yarns
having different colors and/or textures are creeled and fed the various
needles of the needle bar or bars.
In a preferred embodiment of the present invention, a tufting
apparatus is provided having a pair of staggered needle bars. The
needles of the front needle bar are fed by front yarn feed rolls, while the
needles of the back needle bar are fed by back yarn feed rolls. Each of
the front and back feed rolls are controlled independently by an
associated servomotor. The servomotors of the front and back feed rolls
are preferably programmed differently to provide different yarn feeds to
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the needles of the associated needle bar, with or without likewise shift of
the needle bars, to provide high and low tufts in warpwise and/or
weftwise adjacent stitches. For example, without shifting the needle
bars, a high or low tuft striping effect may be created in the warp
direction. with one or more rows of low tuft piles exposed to a greater or
lesser extent between one or more rows of high tuft piles. By timing the
occurrences of the formation of the high and low tufts on the front and
back bars, high and low ribs across the fabric face can be formed. By
timing the occurrences of the high pile stitches on the front bar out-of-
phase with the high pile stitches on the back feed roll, an unusual
texture is provided.
When one or both of the needle bars are shifted or stepped in the
weft direction, a pattern of high and low or intermediate height tufts can
be provided in both the warp and weft directions. Unique color
combinations and variations in surface aesthetics can be achieved by a
thread up of different colored yarns and/or yarns of different textures. By
using servomotors to intentionally, precisely and accurately control yarn
feed to provide high and low pile heights within a graphic tufted pattern,
a completely different visual effect is achieved as compared with
employing servomotors to compensate by yarn feed control for the more
or less yarn required upon a needle bar shift to achieve a level surface
in the resulting fabric.
In a preferred embodiment according to the present invention,
there is provided a tufted pile fabric comprising a substrate. and a
plurality of yarns stitched into the substrate in warpwise stitch rows and
spaced weftwise from one another forming a tufted pile on one face of
the substrate, at least one pair of immediately-adjacent tufts having a
difference in height in one stitch row greater than 3/32 inch (2.38 mm).
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In a further preferred embodiment according to the present
invention, there is provided a method of manufacturing a tufted pile
fabric comprising the steps of stitching a plurality of yarns into a
substrate to form a tufted pile fabric and controlling yarn feed during
stitching to provide a pattern effect in the tufted pile fabric with
immediately-adjacent tufts in warpwise rows thereof having differences in
heights of the tufts relative to the substrate and to one another, including
(i) providing a servomotor for driving a yarn feed roll and (ii)
incrementally advancing the yarn feed roll under control of the
servomotor to provide the pattern effect in the tufted pile fabric including
the differential heights of the tufts
In a still further preferred embodiment according to the present
invention, there is provided a method of manufacturing a tufted pile
fabric comprising the steps of stitching a plurality of yarns from a yarn
feed roll into a substrate to form a tufted pile fabric and effecting a
pattern in the tufted fabric of different tuft heights in one-tuft increments
in the warp direction by (i) providing a servomotor for driving the yarn
feed roll and (ii) incrementally advancing the yarn feed roll under control
of the servomotor to provide the pattern in one-tuft increments.
Accordingly, it is a primary object of the present invention to
provide a novel and improved tufted fabric and methods of making the
tufted fabric using servomotor controlled yarn feed rollers to create
texture and patterns in the fabric.
BRIEF DESCRIPTION OF THE DRAWINGS
r
FIGURE 1 is a schematic representation of a tufting apparatus for
forming the tufted fabric according to the present invention;
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FIGURE 2 is a fragmentary perspective view illustrating the tufted
surface of a fabric constructed in accordance with the present invention;
FIGURE 3 is a cross-sectional view thereof taken generally about
on line 3-3- in Figure 2;
FIGURE 4 is a fragmentary perspective view similarly as in Figure
2 illustrating a combined cuVloop pile fabric; and
FIGURE 5 is a fragmentary side elevational view illustrating a
fabric having alternating high cut pile and low loop pile in one stitch.
BEST MODE FOR CARRYING OUT THE INVENTION
Reference will now be made in detail to a present preferred
embodiment of the invention, an example of which is illustrated in the
accompanying drawings.
Referring now to Figure 1, there is illustrated a tufting apparatus
for forming a tufted fabric F. To form fabric F, a substrate S is provided
on a roll R and is moved linearly in a longitudinal direction, indicated by
the arrow. In the illustrated form, two needle bars are provided for
forming the tufts in substrate S as the substrate moves longitudinally
past the needle bars. Thus, front and back needle bars 10 and 12,
respectively are provided, although it will be appreciated that a single
needle bar may be used in the present invention. As well known, each
needle bar 10 and 12 includes a plurality of needles N spaced one from
the other in the weft direction, with the needles of one bar being
staggered weftwise relative to the needles of the other bar. The needle
bars 10 and 12 are mounted for reciprocating movement toward and
away from substrates i.e.. in the vertical direction indicated by the
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double arrows. Yarn Y is fed from a pair of feed rolls 14 and 16 from
supply creels, not shown, to the eyes of the needles of the respective
needle bars 10 and 12. It will be appreciated that a plurality of yarns are
fed to each of the front and back feed rolls 14 and 16, as is
conventional. Servomotors 18 and 20 are drivingly coupled to the feed
rolls 14 and 16, respectively, for incrementally advancing the feed rolls
and hence the yarns for supplying the yarns to the needles of the front
and back needle bars, respectively. The operation of the servomotors
18 and 20 is under the control of a computer C, which, in accordance
with the present invention, instructs the servomotors to drive the feed
rolls to supply the same or a greater or lesser extent of yarns in each of
the front and back needle bars in accordance with a predetermined
program.
In an exemplary embodiment of a tufting apparatus for use in
producing a tufted fabric, e.g., a carpet, according to the present
invention, the front and back needle bars 10 and 12, respectively. may
be spaced one from the other in the warp direction of the tufting machine
a distance, for example, of .25 inches. The needles on each needle bar
may be spaced one from the other in the weft direction on 1/5 inch (5.08
mm) centers and. hence, the needles of the front and back needle bars
provide a 1/10 gauge. For manufacturing a typical twelve-foot wide
carpet, for example, there would be a total of 1,440 needles in a 1/10
GA tufting machine with each needle bar carrying 720 needles and
hence 720 discrete yarns.
While not shown in the drawings. each needle bar is associated
with a plurality of weftwise spaced loopers for forming tufted loop pile or
with hooks-and-knives for forming tufted cut pile. The loopers or hooks-
and-knives are. of course located below the substrate S as viewed in
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Figure 1. a separate set of loopers or hooks-and-knives being provided
each needle bar.
In accordance with the present invention, servomotors 18 and 20
are provided to independently adjust the yarn feed precisely and
accurateiy for each of the front and back feed rolls 14 and 16,
respectively, in a predetermined number of increments. For example,
eight different increments of movement may be provided within a
predetermined total range of movement. In this example. therefore,
eight different yarn feeds may be provided each of the front and back
feed rolls independently of one another. Thus, various combinations of
yarn feeds among the front and back feed rolls are provided. Also. a
selected yarn feed corresponding to a selected increment of the
servomotor is programmed for each weftwise row of stitches in the fabric
to provide a preselected height of tuft in that row. Accordingly, by
variously incrementally adjusting the servomotors under computer
control, the magnitude of the yarn feed for each needle bar for each
weftwise row of stitches is predetermined. The height of each tuft above
the substrate in each weftwise extending stitch row can therefore be
selectively accurately and precisely adjusted by preselecting the
incremental advance of the associated servomotor. Thus, the height of
immediately-adjacent stitches in each warpwise extending row can be
varied precisely and accurately according to each selected increment of
seNomotor advance. Further, by placing yarns of various colors or
textures. or both, in a planned thread-up for each needle bar. a wide
variety of patterning can be provided.
By employing seNomotor driven yarn feed rolls, the present
invention achieves patterning effects in the fabric surface not heretofore
obtainable. This is due to the ability of the seNomotor to accurately and
precisely control the yarn feed for each warpwise stitch such that the
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height of next-adjacent tufts in the warp direction can be accurately and
precisely controlled. That is, the servomotors provide the instantaneous
response necessary for the accurate and precise underfeed or overfeed
of the yarn to form the desired pile height in the pattern. Particularly,
this permits jumps in heights between next-adjacent warpwise tufts in
excess of 3/32 inch (2.38 mm) and which height jumps were not
obtainable without tufts of in-between height intervening between
immediately-adjacent warpwise tufts in fabrics produced by prior tufting
machinery. Also because of the use of two needle bars. timed in
operation relate to one another, the present invention also provides for
accurate and precise differences in height between next-adjacent
stitches in the weft direction including height differentials in excess of
3/32 inch (2.38 mm).
Referring now to a specific embodiment of the present invention
illustrated in Figure 2. there is provided a tufted loop pile fabric
comprising the substrate S and a plurality of rows of stitches forming
tufts extending in the machine or warp direction, as indicated by the
arrow. The needle bars 10 and 12 and individual needles on those bars
are also schematically illustrated. It will be appreciated that Figure 2
illustrates the fabric from the tufted side of the fabric, the needle bars 10
and 12 forming the tufts from the underside of the substrate S in this
view. In contrast, the illustration in Figure 1 shows the manufacture of
the fabric. with the backside of the substrate facing upwardly and the
tufts facing downwardly from the substrate. The step of the needle bars
10 and 12 in the weft direction is illustrated by the weftwise distance
between the dashed lines from the needles to the stitches formed by
those needles.
In this form of exemplary fabric, it will be appreciated from a
review of drawing Figure 2, that a plurality of rows of stitches are
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formed, with the stitches in each row in the warp direction having two
high piles followed by two low piles with that configuration being
repeated in the machine direction Additionally, the two high piles in
each warpwise stitch row lie in registration with two low piles in the
adjoining stitch row. Depending upon the relative difference in height
between high and low tufts, the low tufts will, for large height
differentials, be obscured or blocked from view by the high tufts. For
example, where the difference in height between the high and low tufts,
whether in the warp or weft directions. or both, is about 5/32 inch (3.97
mm) or more, the low piles will be substantially obscured from view in a
1/10 gauge fabric with a 1/4 inch stagger between needle bars.
Obviously, the nature of the pile yarn will also, to some extent, determine
whether or not the low loop tufts are obscured and the difference in
height between the high and low tufts necessary for those low tufts to be
obscured .
It will be appreciated that a variety of patterning effects may be
accomplished by varying the high and low tufts within the fabric. For
example, a striping or ribbing effect in the warp direction can be
accomplished by maintaining the tufts in one or more weftwise adjacent
rows in a low pile configuration, while an intervening row or rows of tufts
in the warp direction have a high pile configuration. High and low
checkerboard patterns can be obtained, for example. Also, meandering
high and low patterns can be provided throughout the fabric. It will be
appreciated that these various combinations of high and low tufts can be
provided because of the precise and accurate incremental yarn feed
control, and hence yarn height control for each tuft, afforded by the
servomotors. This precision and accuracy of control in the formation of
patterns in the fabric has heretofore been unknown and particularly
controlling heights in the warp direction of immediately-adjacent tufts in
excess of 3/32 inch (2 38 mm) height differentials.
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11
Additional aesthetic characteristics can be accomplished by color
variations in and/or textures of the plurality of yarns provided the fabric.
For example, and for color variation, if the yarns supplied the front
needle bar 10 have a three-color repeat for needles 1, 3 and 5 across
the machine width, then similarly the yarns supplied the back needle bar
12 have a three-color repeat for needles 2, 4 and 6 (the colors in each
needle bar being different). ~/ariations in color readily appear in the
fabric depending on weftwise movement of the needle bars and pile
height. For example, for most yarns and fabrics, the low loop will be
obscured, and hence their colors, by the adjacent high loops if the height
differential exceeds a predetermined value, e.g., 5/32 inch (3.97 mm).
Figure 2 illustrates a single-step sequence for each needle bar for
each stitch. That is, the front and back bars move one step in opposite
weftwise directions for each stitch for a predetermined number of steps
before returning in similar but opposite steps to the neutral position.
Thus, for the first transverse stitch row a, yarns 1, 3, 5 of different colors
appear in warpwise stitch rows A, C and E as high loops. In that same
transverse stitch row, different color yarns 2, 4 and 6 appear as low
loops in warpwise stitch rows B, D and F. In the next warpwise stitch
row the needle bars 10 and 12 have been shifted one step in opposite
weft directions as indicated by the arrows. Accordingly, yarn 1 appears
in weft stitch row b, warp row C as a high loop. Yarn 3 appears in weft
row b. warp row E as a high loop. Stitch yarn 5 appears in weft row b
warp row G as a high loop. With the shift of the back needle bar 12,
yarn 2 is shifted from warp row H, weft row a, to warp row F, weft row b
and appears as a low loop. Yarn 6 shifts from warp row F, weft row a.
to warp row D, weft row b and appears as a low loop. Yarn 4 shifts from
warp row D, weft row a to warp row B, weft row b and appears as a low
loop.
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Upon the second shift of needle bar 10 to the right stitch yarn 1
becomes a low loop in warp row E, weft row c and, in the next stitch and
after the next step, becomes a low loop in warp row G, weft row d as a
low loop. Stitch yarns 3 and 5 are similarly shifted in location and
height. Stitch yarn 2, upon the second shift of needle bar 12 to the left.
becomes a high loop in warp row D, weft row c and, in the next stitch.
becomes a high loop in warp row Bl weft row d. Stitch yarns 4 and 6
are similarly shifted in location and height.
The pattern repeats itself throughout the fabric. with a
predetermined number of steps of the needle bars and stepped return
before the sequence is repeated. The servomotors are incrementally
advanced to provide additional yarn to accommodate the further yarn
needed to step from one warp row to a different warp row for each stitch
in the illustrated form and also any more or less yarn to provide precise
and accurate height control.
Consequently! with a height differential between the high and low
loops sufficient to obscure the low loops from view, e.g., 5/32 inch (3.97
mm). the colors of yarns 1, 3 and 5 appears in the fabric when the tufts
formed by yarns 1, 3 and 5 form high loops and are obscured in the
fabric when the tufts formed by yarns 1, 3 and 5 form low loops.
Similarly, the colors of yarns 2! 4 and 6 appear in the fabric when the
tufts formed by yarns 2, 4 and 6 form high loops and are obscured in the
fabric when yarns 2, 4 and 6 form low loops. With the virtually unlimited
patterns of high and low tufts and variations in color available, coupled
with the capacity to precisely and accurately control the height of the
tufts from stitch to stitch including height differentials in excess of 3/32
inch (2.38 mm), a wide variety of different patterns and textures is
available.
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It will be appreciated that the foregoing description with respect to
Figure 2 applies equally to cuVloop piles and is not limited to the
illustrative example of looped pile fabric. Additionally. the present
invention is applicable to combined cuVloop pile fabrics. e.g.. illustrated
in Figure 4. Thus, a pattern of low loops and high cut loops 30 and 32,
respectively. may be provided as illustrated similar to the previously
described pattern but with the high loops cut.
With reference to Figure 5, there is illustrated a fabric having
alternating high cut tufts and low loop tufts for each stitch. The high cut
tufts 36 and the low loop pile 38 provide a difference in tuft height in
successive stitches in excess of 3/32 inch (2.38 mm) between
immediately adjacent stitches in the warp direction. In the illustrated
form, the rows of stitches alternate vis-a-vis the location of the high cut
tufts and the low loop tufts in the weft direction.
In a preferred embodiment and as a representative example
hereof, the tufting machine may be driven at 500 rpm to provide about
8.33 stitches per second. Accordingly, the present invention can provide
a difference in tuff height in excess of 3/32 inch (2.38 mm) between
immediately-adjacent stitches in the warp direction in about .24 seconds
and this can be accomplished with a needle bar shift of up to three
gauges. At a maximum speed of about 1100 rpm, about 18 stitches per
second can be provided affording a difference in tuft height in excess of
3/32 inch (2.38 mm) between immediately-adjacent stitches in the warp
direction in about .11 seconds.
While the invention has been described with respect to what is
presently regarded as the most practical embodiments thereof. it will be
understood by those of ordinary skill in the art that various alterations
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and modifications may be made which nevertheless remain within the
scope of the invention as defined by the claims which follow.
