Note: Descriptions are shown in the official language in which they were submitted.
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1 METHOD AND APPARATUS FOR HEAT-TREATING TUBULAR KNIT FABRICS
TECHNICAL FIELD
The invention concerns a method and apparatus for subjecting
5 a knitted tubular fabric to a dry high temperature in
order to reorient the knitted stitch geometry of the fabric
while maintaining a predetermined width of the fabric
under a controlled longitudinal tension condition and
allowing the fabric to set while maintaining the controlled
10 longitudinaltension condition.
BACKGROUND ART
Heretofore knitted tubular fabrics made of natural fibers
such as cotton, wool or silk have been heat treated with
steam in order to reorient and set the knitted stitch
geometry of the fabric in an attempt to provide for a
balanced control of shrinkage in both the longitudinal
and lateral dimensions. This has been accomplished by
spreading the knitted tubular fabric over a spreader
20 frame while at the same time reducing or eliminating
tension in the length direction and subjecting the fabric
to a steam treatment. The natural fibers being hydro-
scopic absorb moisture from the steam where the moisture
then acts as a lubricant to allow the knitted stitches
25 to sllp relative to each other. This slippage in turn
alters the knit geometry so as to neutralize or balance
tension forces in the longitudinal and lateral directions
of the fabric so that the fabric may be subsequently
cut into garment segments of a desired size and material
30 yield.
Steam treatment is not applicable for altering the stitch
geometry of knitted fabrics made from synthetic fibers,
blends of synthetic and natural fibers or from fibers
treated with thermo setting resins and where any
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1 alteration is permanent enough for the fabric to be trans-
ported from the steam treatment station to a cutting table
where the fabric is cut into garment segments. This is
because fabrics made from synthetic fibers or resin
5 treated fibers have memories that may be altered only
by subjecting the fibers to temperatures near to that
at which the fibers were f3rmed or near to that which
the resins become reactive which temperatures are usually
on the order of 300-400F. and well above the temperature
10 of steam at atmospheric pressure.
Apparatus has been utilized in the past to transport
synthetic knitted tubular fabrics through a dry high
temperature heat treating station in an attempt to alter
stitch geometry but no means was provided in such apparatus
for holding the tubular fabric out to a desired or pre-
determined width in the heat treatment zone. Instead the
fabric was pre-spread and steamed before entry into the
high temperature zone with the purpose of providing a
temporary set in the fabric while the temperature of
its fibers wasincreased to the plastic state in the high
temperature zone. However in such instances the fabric
almost always contracted in width because there were no
means provided for holding the width and usually the fabric
grew in length because of the longitudinal tensions imparted
to the fabric by pulling it through the heat treatment
station. Other attempts have been made to treat syn-
thetic fabrics by holding the width by pulling a knitted
tube of fabric over a stationary wire frame but no means
have been provided to control length and width tension
30or fabric geometry while it is being subjected to the high
temperature treatment, and fabric treated by such machines
is usually distorted and leaned out.
Further the use of wet steam alone in order to impart a
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1 set to knitted fabrics having a brushed surface has been
unsuccessful. This is because the steam kills the nap
on such fabrics prior to setting in that it reduces
formation of static electricity which causes the nap to
rise.
It is therefore an object of my invention to provide
a method and apparatus for applying a dry high tempera-
ture heat to a knitted tubular fabric while at the same
time maintaining a predetermined width in such fabric
and maintaining a relaxed or reduced longitudinal tension
in the fabric. Such method and apparatus will allow the
stitch geometry of fabrics made from snythetic fibers,
blends of synthetic and natural fibers or fibers treated
with thermo setting resins to significantly alter and to
set so that a balanc~ shrinkage control of the fabric
is maintained in both lateral and longitudinal directions
and so that the fabric may maintain predetermined sizes
after being cut into garment segments.
It is a further object of my invention to provide ~4~r~
a method and apparatus for treating knitted brush-type
fabrics with heat wherein the nap of the fabrics will not
be reduced by the particular heat treatment utilized.
DISCLOSURE OF INVENTION
Broadly the method of my invention comprises the steps
of moving a knitted tubular fabric over a spreader means
to spread the fabric into a flattened tubular form of
a predetermined width while at the same time imparting
a lateral tension to the fabric. The inside edges of
the flattened tubular form are engaged by a first edge
drive means to move the flattened tubular form
over the spreader means towards an edge drive transfer
station while maintaining the predetermined width. At
the edge drive transfer station, the first drive means
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is removed from engagement with the tubular form and re-
placed by a second edge drive means while still maintaining
the predetermined width. The speed of the first drive means
is regulated with respect to the second drive means in order
5 to control longitudinal tension in the flattened tubular
form while it is engaged by the second drive means. The
tubular form is then moved by the second drive means through
a dry temperature heat treating station while maintaining
the predetermined width and control of longitudinal tension
10 to the form in the heat treating station to cause the
knitted stitch geometry to alter and remove lateral tension
therefrom. The fabric is then removed from the heat
treatment station and allowed to cool and set while engaaed
by the second drive means. The fabric if desired may be
treated with steam prior to passing through the heat
treatment station in order to provide a temporary set while
being subjected to the dry heat treatment.
The apparatus of my invention comprises broadly a spreader
20 means for spreading a knitted tubular form to a flattened
form of predetermined width. A first drive means is
provided for engaging the inside edges of the flattened
tubular form to move the form over the spreader means
to give the predetermined width and which results in a
lateral tension being imparted to the form. A drive
transfer station is provided for transferring engagement
of the first edge drive means to a second edge drive means
while maintaining the predetermined width of the tubular
form. Means for varying the speed of the second drive
means with respect to the first drive means is provided so
that the speed of the fabric moved by the first drive means
may be regulated with respect to the fabric engaged by the ~
second drive means to control longitudinal tension. The second
drive means e~tends through aheat treating station in which a
dry heat preferably in excess of 300F. may be applied to the
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fabric to alter the stitch geometry of the fabric and to
remove the lateral tension. A cooling station is provided
through which the second drive means extends wherein the
fabric may cool to impart a permanent set to the altered
5 stitch geometry.
Preferably the first and second edge drive means each
comprise a driven endless belt for engaging an inside
edge of the flattened tubular form and wherein the belt
10 of the second drive means extending through the heat
treatment station comprises a heat resisting material.
Further the apparatus may include an air cooler at the
cooling station for directing a blast of cooling air onto
the tubular form to expedite setting of the modified
stitch geometry.
BRIEF DESCRIPTION OF DR~WINGS
Figure l is a side view of the device constructed
20 according to the invention;
Figure 2 is a broken plan view of the device of Figure
l;
Figure 3 is an enlarged view of a portion of Figure 2
illustrating a spreader means and an edge drive means;
25 E~igure 4 is an enlarged side view of Figure 2 taken
along lines 4-4;
Figure 5 is an enlarged sectional view of a portion of
Figure 3 taken along lines 5-5;
Figure 6 is an enlarged sectional view of Figure 3 taken
30 alng lines 6-6;
Figure 7 is an enlarged partial sectional view of Figure
3 taken along lines 7-7; and
Figure 8 is an enlarged sectional view of Figure 2 taken
along lines 8-8.
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BEST MODE FOR CAP~RYING OUT THE I~IENTION
Referring to Figure 1 there is illustrated a machine 1
for heat treating knitted tubular fabrics where the
apparatus has an entry station 10, a spreader-control
5 station 20, an edge drive transfer station 60, a heat
treating station 70, a cooling station ~0 and a batcher
station 90.
The entry station 10 comprises a frame 11 supporting a
10 supply roll 12 of a knitted tubular fabric. A tubular
web W is drawn from the roll 12 and extends over upper
idler rolls 13 and 14 and passes over tension rods 15 and
thence over idler rolls 16. The web W then passes over
a spreader means 21 which extends into the interior of the
15 tubular fabric to spread the fabric to a predetermined
width and at the same time to impart a lateral tension
to the tubular web W.
The spreader-control station 20 including the
20 spreader means 21 is illustrated in greater detail in
Figure 3 as comprising in part a smooth bow portion 22
adapted to engage the inside edges of a tube of fabric
to spread the same into a flattened tubular form of a
desired width. The bow portion 22 is connected to spreader
25 side frames 23 which extend through a major portion of the
length of the machine 1 from ahead of the spreader-control
station 20 through and including the cooling station 80.
Frames 23 serve to support two first edge drive means
24 and two second edge drive means 25 to move the web
30 W of the tu~ular fabric through the machine and where
each of the edge drive mear.s is adapted to engage an
inside edge of the flattened tubular form.
As shown in Figure 3, each first edge drive means 24
35 comprises an endless belt 24' which passes over a front
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1 idler pulley 26, a rear driven pulley 27, a plurality
of supplemental idler pulleys 28 and a moveable tension
adjusting pulley 29 where all of the pulleys are rotatably
carried by frame 23. In addition the belt passes over
5 a frustoconical idler wheel 30 carried by frame 23 which,
through the medium of the web W as shown in Figure 7, is
supported by the rubber covered rolls 31 mounted on shafts
32. Rolls 31 thus serve to freely support the forward
end of the spreader means within the tubular form of
10 fabric.
The spreader-control station 20 may, but not necessarily,
also include an upper control roll 35 and a lower control
roll 36 adapted to be respectively driven in opposite
directions by a variable speed drive not shown. Rolls 35
and 36 are adjustable by means illustrated in my Patent
No. 3,973,305 whereby the clearance between the rolls
may be varied. Further shafts 32 upon which the rubber
covered feed rolls are mounted may be driven by a variable
20 speed drive not shown. By varying the relative speed of
the control rolls and the rubber feed rolls 31, the control
station may be used as a straightening calendar for
finishing transversely striped or patterned circular
knit fabrics in the manner disclosed and described in
25 my Patent No. 3,973,305.
An abutment roll assembly 45 as more fully illustrated
in Figure 4 is mounted onto the spreader frame 23 and
includes rolls 46 rotatably mounted with respect to the
30 spreader frame 23 and over which the web W passes such that
the web is interposed between the rolls 4~ ardthe control
rolls 35 and 36. The abutment rolls thus serve to
position the spreader means longitudinally in the machine
1 and prevent the spreader means from being pulled through
the machine when fabric is run through the machine.
1 Referring to Figures 3 and 5-8, the second edge drive
means 25 like the first edge drive means 24 is adapted
to engage each inside edge of a flattened tubular form
and comprises an endless belt 50 which passes over a
5 forward idler pulley 51, supplemental idler pulleys 52
and a rear driven pulley 53. The belt 50 comprises a
heat resistant material and preferably a stainless steel
belt which may withstand the high temperatures generated
at the heat treating station.
An edge drive transfer station 60 by which driving
engagement of the first drive means with respect to the
tubular form is transferred to the second drive means is
illustrated in detail in Figures 5 and 6. As shown the
rear driven pulley 27 of the first edge drive means
comprises a center portion 61 fixedly mounted on shaft
62 and over which belt 24' extends. Also fixedly mounted
to the shaft 62 are outer portions 63 each of which has a
convex end surface 64. The convex end surfaces 64 of por-
20 tions 63 are complementary to concave surface 65 ofa driven edge drive member 66 as shown in Figure 6.
As drive member 66 engages the outer edge of the ~eb W,
it will transfer driving force through the web *o the
outer portiors63 and in turn to the center portion 61
25 and onto the drive belt 24' to provide the driving force
necessary to pull the web over the spreader means 21
and cause the web to be stretched to a predetermined
width. Further, because of the engagement between the
concave surfaces 65 and convex surfaces 64, the driven
30member 66 will provide a vertical support for the rear
driven pulley 27 and the associated spreader frame 23.
As an alternative construction, the first drive means could
comprise the rear driven puLley 27 alone and where the bow
portion 22 would be extended to the transfer station. In
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1 such a construction, the pulley 27 driven by the drive roll
66 would engage the inside edges of the tubular fabric to
act as an edge drive means and to provide sufficient force
to move the tubular form over the spreader to the transfer
5 station and to control the feed of the tubular form with
respect to the second edge drive means.
The forward idler pulley 51 of the second edge drive
means 25 is mounted on a shaft 54. Also mounted on shaft
10 54 are sections 55 which are freely rotatable with respect
to pulley 51 and which have convex outer surfaces 56.
Surfaces 56 act with concave surface 65 through the web W
to provide a vertical support to the spreader frame in the
same manner as with the first edge drive means.
Driven member 66 is connected by means of a variable speed
control 67 and belt 68 to a drive motor 69 of the machine
such that the speed control provides means for regulating the
speed of the first edge drive means.
The rear pulley 53 of the second edge drive means has a
convex outer surface 57 which is complementary to a concave
surface 58 of a drive pulley 59 such that the drive pulley
will provide a vertical support for the idler pulley 53
and the associated spreader 23. Driving force for the second
edge drive means to move the tubular form from the edye
drive transfer station is thus provided by the drive pulley
59 through the web W onto the driven pulley 53 and thence
to the belt 50 which engages the inside edges of the tubular
form. Drive pulley 59 is connected to a variable speed
control unit 85 in turn connected to the main drive motor
69 of the machine by belt 86.
The heat treating station 70 comprises a housing 71 having
a plurality Gf dry high temperature heaters 72 therein
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1 positioned beneath and above the fabric which may heat
fabric passing through the heat treating station in excess
of 300~. Preferably the heaters are infra-red heaters but
could be of another type, for example gas heaters. The
5 number of heaters required is in part determined by the
speed of the fabric moving through the heat treating station
with more heaters needed as faster speeds than at lower
speeds since the fabric temperature must be raised to high
temperatures in less time than when moving at slower speeds.
The heating station may also include an air knife blower
unit 73 which circulates air lengthwise of the tubular form
in the heat treating station when the machine is stopped to
prevent overheating of the fabric. In addition an exhaust
15 housing 74 is provided to remove smoke generated in the
heat treating station.
Cooling station 80 includes air coolers 81 for blowing
cooling air on to both sides of the tubular form of fabric
20 in order to assist and expedite setting. If the cooling
station is sufficiently long and the speed of movement of
the fabric sufficiently slow, the coolers 81 may be dispensed
with as the fabric would cool enough to set prior to
batching.
The batching station 90 includes conventional driven
draw rolls 91 and 92 for moving fabric from the cooling
station and a driven wind-up roll 93 where the treated
fabric is wound.
In some instances it may be desirable to steam treat the
tubular fabric prior to entry in the heat treating station.
.s shown in Figure 1 a steam unit 75 may be provided for
this purpose.
!
As shown in Figure 2, the spreader frames extend from a
position prior to the control station 20 to a position
after the cooling station 80. This length of the spreader
allows the tubular form of fabric to be shaped to the pre-
determined width by the bow 22 and this width is maintainedthroughout passage of the fabric throùgh the machine, and
particularly through the heat treating station where the
stitch geometry is altered to relieve lateral tension
and in the cooling station where the reoriented fibers are
set. The vertical support required for a spreader of such
length is provided in at least two positions by the edge
drive transfer station construction utilizing the concave
driven member 66 and the edge drive construction of the second
edge drive means utilizing the concave driven pulley 58.
In addition support may be provided by the rubber covered
rolls 31 of the control station but it is to be understood
that the control station and its components are not neces-
sary parts of my invention.
The operation of the machine is as follows. As the tubular
web W is pulled over the bow 22 by the first edge drive
means 24, the tubular web is shaped to a flattened tubular
form with the belts 24' engaging both inside edges of the
form. The spreading of the tubular form imparts a lateral
tension to the form. The flattened form is moved to the
edge drive transfer means by the belts 24' where the
outer edge of the form is engaged by the drive pulley 66
and moved over to the parts 55 of the second edge drive
means. The speed of the first edge drive means is usually
set greater than that of the second edge drive means such that
the tubular form bunches up on the second edge drive means
to form traverse or laterally extending pleats P as shown
in Figure 2. This bunching up relaxes the fabric in the
longitudinal direction to reduce and control longitudinal
tension. The bunched up tubular form is then carried into the
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1 heat treating station by the second edge drive means where
the stitch orientation of the fabric is altered by the heat
and where lateral tension is relieved or balanced with
respect to the longitudinal tension. In some instances,
5 however, it may be desirable to impart longitudinal tension
into the fabric while it is treated. In such event the
speed of the first drive means would then be set lower than
that of the second drive means such that the fabric moving to
the transfer means is underfed with respect to the fabric moving
10 from the transfer means.
The second edge drive then moves the tubular form to the
cooling station where the fibers of the reoriented stitches
are allowed to set. The tubular form is then pulled from
the second edge drive means by the draw rolls 91 and 92
of the batcher station and by the winding up movement of the
wind-up roll 93.
It is seen that the machine 1 provides a support to the
20 tubular form through means of the second edge drive means
both in the heat treating station and in the cooling station
to insure that the lateral and longitudinal tensions of the
fabric will be balanced and that the fabric when cooled
will retain their balanced condition.
