U.S. patent number 3,781,952 [Application Number 04/846,457] was granted by the patent office on 1974-01-01 for textile treatment method and apparatus.
Invention is credited to Robert K. Stanley.
United States Patent |
3,781,952 |
Stanley |
January 1, 1974 |
TEXTILE TREATMENT METHOD AND APPARATUS
Abstract
Textile yarns or strands are heated, as by contact with hot
rolls, and if undrawn are also drawn by roll contact, and then are
compressively crimped.
Inventors: |
Stanley; Robert K. (Media,
PA) |
Family
ID: |
27578696 |
Appl.
No.: |
04/846,457 |
Filed: |
July 31, 1969 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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717882 |
Apr 1, 1968 |
3500519 |
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680851 |
Nov 6, 1967 |
3518733 |
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684230 |
Nov 20, 1967 |
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678428 |
Oct 26, 1967 |
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606420 |
Dec 30, 1966 |
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835883 |
Jun 9, 1969 |
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684230 |
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678420 |
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302758 |
Jul 31, 1963 |
3376622 |
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216524 |
Aug 13, 1962 |
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717882 |
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600986 |
Dec 12, 1966 |
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606420 |
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386489 |
Jul 31, 1964 |
3317977 |
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216447 |
Aug 13, 1962 |
3145947 |
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835883 |
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650762 |
Jul 3, 1967 |
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349338 |
Mar 4, 1964 |
3348283 |
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Current U.S.
Class: |
28/221; 28/249;
28/268; 28/246; 28/265 |
Current CPC
Class: |
B65H
57/12 (20130101); B65H 59/10 (20130101); D02J
1/22 (20130101); B65H 59/16 (20130101); D02G
1/12 (20130101); B65H 2701/31 (20130101) |
Current International
Class: |
D02G
1/12 (20060101); D02J 1/22 (20060101); B65H
57/00 (20060101); B65H 57/12 (20060101); B65H
59/16 (20060101); B65H 59/10 (20060101); D02g
001/12 () |
Field of
Search: |
;28/1.6,62,71.3,72.14 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Rimrodt; Louis K.
Attorney, Agent or Firm: McClure, Weiser & Millman
Parent Case Text
This application is a continuation-in-part of each of my following
(parenthetically enumerated) pending applications, each of which is
listed with reference to previously copending applications and
their predecessor applications with which there was continuity and
the benefits of all of which are claimed for this application:
O. Ser. No. 717,882 filed 1 Apr. 1968, now U.S. Pat. No. 3,500,519,
which was continuation-in-part of Ser. No. 600,986 filed 12 Dec.
1966 and subsequently abandoned; and Ser. No. 680,851 filed 6 Nov.
1967 and now U.S. Pat. No. 3,518,733.
I. Ser. No. 684,230 filed 20 Nov. 1967 and (ii) Ser. No. 678,428
filed 26 Oct. 1967, both as continuations-in-part of Ser. No.
302,758 filed 31 July 1963 and now U.S. Pat. No. 3,376,622, which
was in pertinent part a continuation of subsequently abandoned Ser.
No. 216,524 filed 13 Aug. 1962; and
III. Ser. No. 606,420 filed 30 Dec. 1966, as a continuation-in-part
of Ser. No. 386,489 filed 31 July 1964 and now U.S. Pat. No.
3,317,977, which was in pertinent part a continuation of Ser. No.
216,447 filed 13 Aug. 1962 and now U.S. Pat. No. 3,145,947; and
IV. Ser. No. 835,883 filed 9 June 1969 as a continuation-in-part of
subsequently abandoned Ser. No. 650,762 filed 3 July 1967, which
was in pertinent part a continuation of Ser. No. 349,338 filed 4
Mar. 1964 and now U.S. Pat. No. 3,348,283.
Claims
The claimed invention is:
1. A method for treating thermoplastic yarn comprising the steps of
taking the yarn from a supply, advancing the yarn around a roller
arrangement, heating the yarn as it travels around said roller
arrangement, advancing the heated yarn away from the roller
arrangement at a faster rate than the rate at which the yarn
travels around said roller arrangement and thereby drawing the
heated yarn, driving the drawn yarn into a stuffer box crimping
chamber while said drawn yarn is still in a heated condition and
thereby crimping the yarn and forming a plug of crimped yarn, and
removing the crimped yarn from the head of the plug.
2. Apparatus for treating thermoplastic yarn comprising means for
drawing the yarn, means for crimping the drawn yarn by longitudinal
compression and means for winding the crimped yarn, said drawing
means comprising a roller arrangement and means for heating the
yarn and means for advancing the heated yarn away from said roller
arrangement, said heating means being arranged to heat the yarn as
it travels around said roller arrangement and said means for
advancing the yarn being adapted to advance the heated yarn away
from said roller arrangement at a faster rate than the rate at
which the yarn travels around said roller arrangement, said
crimping means including a chamber defining a yarn bunching zone
for forming a plug of crimped yarn and means for driving the drawn
yarn into said chamber while the yarn is still in a heated
condition from said drawing means, said winding means being
arranged to wind the drawn and crimped yarn from the head of the
plug thereof formed by the said chamber.
3. Apparatus for treating thermoplastic yarn comprising means for
drawing the yarn, means for crimping the drawn yarn by longitudinal
compression and means for winding the crimped yarn, said drawing
means comprising a roller arrangement and means for heating the
yarn and means for advancing the heated yarn away from said roller
arrangement, said roller arrangement including a driven roller
having a peripheral surface in contact with which the yarn travels,
said heating means being arranged to heat the yarn as it travels
with said peripheral surface and said means for advancing the
heated yarn being adapted to advance the heated yarn away from said
roller arrangement at a faster rate than the rate at which the yarn
travels with said peripheral surface, said crimping means including
a chamber defining a yarn bunching zone for forming a plug of
crimped yarn and means for driving the drawn yarn into said chamber
while the yarn is still in a heated condition from said drawing
means, said winding means being arranged to wind the drawn and
crimped yarn from the head of the plug thereof formed by the said
chamber.
4. The apparatus of claim 3 wherein said driven roller includes
integral means for heating said peripheral surface.
5. The apparatus of claim 3 wherein said means for advancing the
heated yarn away from said roller arrangement comprises a second
roller arrangement, said second roller arrangement including a
second driven roller having a peripheral surface in contact with
which the yarn travels.
6. The apparatus of claim 5 wherein said second driven roller
includes integral means for heating the peripheral surface
thereof.
7. The apparatus of claim 3 wherein means are provided for varying
the relative rate of speed of said driven roller and said means for
advancing the heated yarn.
8. The apparatus of claim 7, wherein the said driven roller is
driven at a peripheral speed of two and one-half times to five
times slower than the peripheral speed of said second roller and
said second roller passes the yarn at a speed within a range
including 500 meters per minute.
Description
This invention relates to treatment of textile yarns or strands,
including heating pretreatment and optional drawing to increased
length followed by compressive crimping thereof.
A primary object of the present invention is enhanced uniformity in
compressive crimping of textile yarns or strands.
Another object is improvement in configuration or stability (or
both) of crimp therein.
A further object is provision of a combined drawing and crimping
process therefor.
Other objects of this invention, together with means and methods
for attaining the various objects, will be apparent from the
following description and the accompanying diagrams.
FIG. 1 is a schematic representation of the processing of a textile
yarn or strand according to this invention;
FIG. 2 is a schematic representation, largely in block form, of
such processing;
FIG. 3 is a side elevation of means for supplying a textile yarn or
strand for such processing from an illustrated alternative source
package thereof;
FIG. 4 is a front elevation of the components of FIG. 3 taken at an
inclination as indicated at IV--IV; and
FIG. 5 is a schematic representation of a stuffer-crimper useful
according to preceding views, with especial reference to FIG.
2;
FIGS. 6A, 6B, and 6C are schematic representations of stuffer
crimpers so useful and including movable impeding or back-pressure
components;
FIG. 7 is a front elevation, partly cut away, of such a stuffer
crimper in further detail and showing a yarn or strand passing
therethrough;
FIG. 8 is a side elevation of the stuffer crimper shown in FIG. 6;
and
FIG. 9 is a plan view of the stuffer crimper of the preceding
views, less the yarn or strand.
FIG. 10 is a perspective view somewhat stylized, of an arrangement
of drawing components useful according to this invention;
FIG. 11 is a perspective view of an alternative arrangement of
drawing components similarly useful;
FIG. 12 is a schematic representation of electrical circuitry and
related components useful according to this invention; and
FIG. 13 is a schematic representation of other electrical circuitry
and related components useful therein.
In general, the objects of the present invention are accomplished,
in the treatment of textile yarns or strands, by heating the same
without sliding contact with any solid heating surface, and then
compressively crimping the same, as in a stuffer crimper having a
temporarily confining chamber defining an accumulating or bunching
zone therefor. If drawable to increased length, whether undrawn or
only partially drawn, the yarns or strands are passed in
essentially non-slipping contact with successive sets of rolls
rotating at successively increasing surface speeds and are so
heated as to ensure drawing as well as crimping thereof, after
which they are cooled or allowed to cool.
FIG. 1 shows, largely schematically, strand 10 unwinding over the
end of conical package 11 and thereby acquiring a slight twist, to
be withdrawn linearly or lengthwise and be so advanced or forwarded
through guide 12 and successive pairs of rolls 13, 13' and 15, 15'.
Enclosure 14, which may be heated, as by hot-air convection or by
an electrical radiant-heating element (not shown) or which may
simply constitute a barrier to loss of heat to the atmosphere from
the yarn or strand, which is readily heated by the rolls, extends
thereabout between the respective sets of rolls and may extend to
or even about the rolls, if desired.
Although not illustrated, methods and means for heating the rolls,
preferably internally, will come readily to the mind of a person
skilled in the art: e.g., by circulation of heated fluid therein or
by electrical means as disclosed in my U.S. Pat. No. 3,111,740,
especially FIGS. 6 to 8 and the description thereof. Traversing
means 16, optionally used for assisting in distribution of the yarn
or strand along the nip of feed rolls 17, 17', follows the second
pair of rolls and precedes the feed rolls at the entrance to
stuffing chamber 18, to which the yarn or strand proceeds directly
from rolls 15, 15'. Compressively crimped yarn or strand 10' (so
designated to distinguish it from the uncrimped starting form) is
wound up from the exit of the chamber past aftertreating means 19,
in which it is adjusted in tension (such as in my U.S. Pat. No.
3,500,519) or temperature (or both) and onto traverse-wound package
21 by self-traversing drive roll 20 rotating in contact
therewith.
FIG. 2 shows schematically the location of heating, intermediate,
and cooling zones, represented in block form, between the supply
and windup components of FIG. 1. After leaving guide 12, yarn or
strand 10 passes successively through Heating Zone 24, which has
initial and final boundaries A and B; Intermediate Zone 25, which
has initial and final boundaries B and C; and Cooling Zone 26,
which has initial and final boundaries C and D; after which it is
wound by roll 20 onto package 21 as previously mentioned. Location
W in the heating zone, locations X and Y in the intermediate zone,
and location Z in the cooling zone are characterized further
below.
It will be understood that conical package 11 may be replaced by
any suitable source of yarn or strand 10, such as traverse-wound
package 31 shown in side and front (slightly inclined) elevation,
respectively, in FIGS. 3 and 4. This package is mounted for
rotation on axle 32 suitably supported. Mounted on axes parallel
thereto are roll 33 located above and behind the package; roll 34
located below and behind the package, and roller guide 35 located
ahead of and below the package and centered from end to end
thereof. As yarn or strand 10 unreels (without acquiring any twist)
from package 31 and about rolls 33 and 34 and roller guide 35, it
traverses the successive rolls to a successively decreasing extent
as compared with the full traverse thereof on the package, as
indicated by the broken lines. This arrangement smoothes out the
tension changes characteristic of a yarn or strand supplied from a
traverse-wound package, thereby facilitating uniformity of further
treatment and consequent elimination of objectionable
irregularities in the resulting product.
FIG. 5 schematically locates feed rolls 17, 17' and stuffing
chamber 18 with respect to the zones indicated in FIG. 2. Location
X in the intermediate zone is denoted as coincident with the roll
axes, and location Y (also in the intermediate zone) as at or near
the end of the chamber, wherever the yarn or strand is released
from the impeding force or back-pressure that applies crimping
stress thereto.
FIGS. 6A, 6B, and 6C show, also schematically, three conventional
types of stuffing (or stuffer box) chambers 18, with particular
reference to impeding or back-pressure elements for the yarn or
strand therein, in the order of their development: gravity-actuated
or spring-loaded gate 37 in FIG. 6A; reciprocating plunger 38,
without or with a central longitudinal bore, in FIG. 6B; and
unidirectionally movable or moving wheel (which also comprehends
belts, etc.) or gear-like element 39 in FIG. 6C. Each of these
types of impeding means applies back-pressure to crimped yarn or
strand 10' seeking to escape from the chamber, or from that part
thereof in which it is under crimping stress, as the feed rolls
(shown previously) or equivalent means forcibly stuff more
uncrimped yarn or strand 10 into the chamber. Examples of these
respective types may be found in U.S. Pat. Nos. 2,686,339,
2,734,229, and 3,027,619; hence, the omission of most details of
their construction. The rate of windup or other withdrawal of
crimped yarn or strand 10' may be synchronized in timed relation to
the rate of feed of uncrimped yarn of strand 10 into the stuffing
chamber as disclosed in my U.S. Pat. Nos. 3,280,444 and 3,388,440,
especially FIGS. 4 to 9 thereof and the related description, if
desired.
FIGS. 7, 8, and 9 show in front elevation, side elevation, and top
plan, respectively, stuffer crimper 40 embodying feed rolls 17, 17'
and stuffing chamber 18, as well as related components. No impeding
element, such as previously illustrated and described, is included
in this view, it being understood that one may be used therewith,
if desired; alternatively, lateral confinement by and friction with
the sidewalls of the stuffing chamber may suffice, as disclosed in
my aforementioned U.S. Pat. Nos. 3,279,025 and 3,386,142. As shown
in FIG. 7, part of the front wall of stuffing chamber 18 is cut
away to reveal crimped strand 10' inside chamber bore 28 being
withdrawn (as by roll 20 of FIG. 1) from the leading or head end of
accumulation 10a thereof in the form of a bunched or compressed wad
or plug in the lower part of the chamber and which otherwise would
extend at lesat to any impeding element used therewith.
Also shown in FIGS. 7, 8, and 9 is frame 42, which supports
stuffing chamber 18 and related components and which has an
inverted U-shape as viewed from the side (FIG. 8). Shafts 47, 47'
for respective feed rolls 17, 17' are journaled in the front and
rear walls of the frame and have intermeshing gears 57, 57' thereon
behind the rear wall of the frame. Shaft 47' also has driven pulley
49 affixed thereon. Motor 51 on the horizontal upper surface of the
frame has shaft 52 on which is drive pulley 53. Belt 54
interconnects pulleys 53 and 49 to transmit rotational force from
the motor to the gears, shafts, and the feed rolls themselves. Also
shown is roll 17" carried on stub shaft 47" parallel to and aligned
with the feed rolls and their shafts, with the peripheral surface
of roll 17" contiguous with the peripheral surface of feed roll 17
on one side thereof as is the peripheral surface of feed roll 17'
on the opposite side. The tapered entrance of the stuffing chamber,
shown schematically in earlier views, extends within the bight of
the feed rolls but is hidden from view by the lower end of the
chamber, the front and rear walls of which overlap portions of the
front and rear faces of the rolls as far as the roll nip so as to
ensure that the infed yarn or strand enters the chamber rather than
possibly escaping therefrom.
The stuffing chamber and other rigid apparatus elements may be made
of steel or other durable material. If desired, the inside wall of
the chamber may be coated (e.g., with tetrafluoroethylene) to
reduce the coefficient of friction, in which event the chamber
should be lengthened accordingly. In the absence of any impeding
element a chamber length of about a yard or meter, with a bore
width of about a quarter inch or a centimeter for use with yarns or
strands of about 10 to 100 denier, has proved suitable for nylon
and similar textile materials, such as will come readily to the
mind of a person skilled in the textile arts.
Prominent among suitable textile compositions are the nylons
(polycarbonamides), e.g., 66 nylon (i.e., polyhexamethylene
adipamide), also 6-nylon, 11 nylon, 610 nylon, and fiber-forming
copolymers thereof, including terpolymers. Other suitable polymeric
materials for yarns or strands to be treated according to this
invention include most of the thermoplastic fiber-forming
materials, such as polyhydrocarbons (e.g., polyethylene,
polypropylene), polyesters (e.g., polyethylene terephthalate),
polyacrylonitrile and copolymers of acrylonitrile with other vinyl
compounds, also copolymers of vinyl chloride and vinylidene
chloride, and polyurethanes. This list is simply exemplary and is
not intended to be exhaustive of suitable compositions, most or all
of which are thermoplastic.
According to this invention, thus far considered, yarn or strand 10
is withdrawn from a suitable source of supply, then is heated by or
between successive sets of rolls without sliding contact with a
heated solid surface and is stuffed while hot into a confining
chamber, within which it is subjected to longitudinal compression
to buckle it into crimped configuration and from which it is then
withdrawn and usually wound up. The entering yarn or strand usually
is fed or driven into the noll nip and the juxtaposed chamber
entrance from along the common internal tangent thereto extended
therefrom, as shown in solid in FIG. 7. Where it is desired to grip
the yarn or strand over a greater distance than is provided by the
nip of feed rolls 17, 17' it may proceed along the alternative
path, shown there in broken lines beginning at the left of the view
and extending about a quadrant or so of added roll 17", downward
through the nip of rolls 17" and 17, about the lower half of roll
17, and then upward to the nip of rolls 17, 17' and the chamber
entrance.
The heated yarn or strand enters the stuffing chamber at desired
crimping temperature, which is dependent upon the composition,
denier, processing rate, time in the chamber, etc., and often is
within the range of 150.degree. to 350.degree.F. So long as it is
under substantial crimping compression it preferably is kept under
adiabatic conditions, or with addition (or subtraction) of heat
such as may be required to compensate for heat loss (or frictional
heating) and thereby to maintain essentially constant-temperature
conditions until completion of crimping. Then heat is removed from
the crimped yarn or strand in the cooling zone to bring it to
approximately room temperature, as by ventilation with cool air or
otherwise, it being recognized that the crimped yarn or strand
probably will have cooled somewhat (e.g., to about 120.degree.F.)
before reaching the stuffing chamber exit. Such cooling prevents
undesired deformation that might occur in hot yarn or strand wound
into package form.
Although the diagrams illustrate only what appears to be a
monofilament, it will be understood that yarns or strands suited
for treatment according to this invention include also
multifilaments and composite structures comprising shorter lengths
(e.g., staple) than are usually considered to be continuous
filaments. Although many, if not all, of the suitable compositions
are drawable to increased length, usually resulting in orientation
of their component macromolecules longitudinally, detailed
consideration of drawability of the yarns or strands being treated
has been deferred to here in this application in the interest of
orderliness and simplicity of description and illustration.
It has been customary to accomplish such orientation of drawable
textile yarns or strands by a drawing process removed or unrelated
in location and time (being prior, usually long prior) with respect
to whatever crimping process is applied thereto to enhance their
bulk, cover, hand, texture, etc. Most crimping processes tend to
extend the subject yarn or strand axially while deforming it
transversely of the longitudinal axis, as in edge-crimping,
gear-crimping, jet-crimping, and twist-crimping. While there might
be reason to believe that it would be feasible to perform such an
extensional crimping process soon after drawing, as together with
performance of one or more additional steps, the same is not true
of a compressive or compressional crimping process, such as stuffer
crimping.
The general view is that the usual time lag between drawing and
stuffer crimping presumably permits the condition of increased
orientation and length to become desirably stabilized. There is a
greater contradiction involved in first extending a yarn or strand
longitudinally and then immediately compressing it longitudinally
than there is in extending it in both a drawing step and a
following crimping step. However, the present invention provides a
drawing step followed by a compressive crimping step without
appreciable time intervening, i.e., as a draw-crimping process.
FIGS. 10 and 11 show in perspective two suitable arrangements for
so drawing yarns or strands to increased length directly before
crimping, each such arrangement consisting of two sets of rolls
variously arranged but flanking a draw pin such as is optionally
useful in localizing the draw. It will be understood that at least
one of the rolls in each of these two sets is driven by suitable
motive means (not shown) and that all the rolls within each set
rotate at constant speed, whether driven directly by the motive
means or indirectly by contact (essentially non-slipping) with one
another. The surface speed of the rolls in the second or forwarding
set is sufficiently greater than the speed of the rolls in the
first or input set to draw the yarn or strand to desired increased
length therebetween. The draw pin does not rotate but is fixed so
as to snub the strand passing about it. The pin may, but need not,
be heated by any conventional means (e.g., electrically or by
steam, preferably supplied internally) in accordance with the art
of textile drawing.
In FIG. 10, a pair of input rolls 61, 62 spaced from one another in
godet fashion precede draw pin 65, and similar pair of output or
forwarding rolls 68, 69 follow the draw pin. Yarn or strand 10
passes successively about the input pair of rolls as a group, about
the draw pin, and about the output pair of rolls as a group.
Additional wraps about the respective pairs of rolls may be
employed if required for essentially non-slipping contact
therewith. See my U.S. Pat. No. 3,518,733 for a similar arrangement
in which the spacer or separator rolls are smaller than the godet
rolls.
In FIG. 11, input rolls 71, 72, 73 arranged in a horizontal
three-roll stack, and output rolls 77, 78, 79 are similarly
arranged. Thus, rolls 71 and 73 flank and are contiguous with roll
72, while rolls 77 and 79 are similarly arranged with respect to
roll 78. Yarn or strand passes about an upper quadrant of roll 71,
through the nip between rolls 71 and 72, about the lower half of
roll 72, through the nip between rolls 72 and 73, and over an upper
quadrant of roll 73 in its path to draw pin 75. From the draw pin
it proceeds in like manner about a quadrant of roll 77, through the
nip between rolls 77 and 78, halfway about roll 78, through the nip
between rolls 78 and 79 and onward to a stuffer crimper, previously
shown. Because the yarn or strand is gripped by successive roll
nips as well as by frictional contact with portions of the roll
surfaces, complete or multiple wraps are not required to ensure
essentially non-slipping roll contact.
It will be understood that either arrangement of draw rolls may be
substituted for pairs of rolls 13, 13' and 15, 15' shown in FIG. 1.
Heating enclosure 14 may be retained or not, as desired, but in
either event it is most convenient and effective to heat one or
both sets of rolls, possibly in addition to (or instead of) heating
the draw pin. Heating the first set of rolls preheats the strand
for drawing, rendering it generally easier to draw, and
incidentally preheating it for crimping, while heating the second
set of rolls in addition thereto, if desired, at least sufficiently
to prevent the drawn strand from cooling in the interim (however
brief) before crimping, is conducive to a steady and high degree of
crimping. Of course, as can be seen readily from the prior
discussion hereinabove, even heating only the second set of rolls
is often beneficial to the degree of crimp. Althougn not
illustrated or further described herein, suitable methods and means
for heating the draw rolls, preferably internally, will be
apparent, such as by use of heated fluid or electrical resistance
elements as mentioned above in the discussion of heating one or
more of rolls 13, 13' and 15, 15'.
The relative speeds of the output and input rolls determine the
draw ratio, which essentially determines the relationship of the
new length of the drawn strand to its former or undrawn length.
Customary draw ratios are in the range from about 2 to 6X, although
sometimes higher draw ratios may be employed and lower draw ratios
may be employed in individual stages of multiple-stage drawing
processes. A common draw ratio for 66 nylon is 4X, corresponding to
an output/input speed ratio of 4 to 1. Practicable processing
speeds are undergoing continual increase and often are in the
vicinity of a thousand yards or meters per minute into the crimping
apparatus, but somewhat slower or faster speeds may be employed.
The speed at which the strand is fed into the crimper often
coincides with the output speed from the drawing zone, and in that
event one or more of the crimper feed rolls may be combined with
(or replaced by) one or more of the output draw rolls. For example,
output draw rolls 77, 78, 79 of the draw system of FIG. 11 may
coincide with rolls 17", 17, 17' of the stuffer crimper of FIG. 7,
using the alternative path (broken lines) for the yarn or strand to
be crimped. Such an arrangement further maintains the desired
elevated temperature thereof and continuity of treatment without
appreciable intervening delay or time lag.
FIG. 12 shows schematically suitable electrical circuitry and
related components useful in assuring the desired heating and
control thereof. Heating region 81, shown in block form, may
constitute (or be part of) Heating Zone 24. Electrical potential E1
provides, via pair of leads 84, the input to electrical bridge 82,
which may be a simple Wheatstone bridge (or a more complex type)
provided with resistors (or other suitable impedance elements) R1,
R2, R3, and R4 in its various arms: resistor R3 being a thermistor
having pair of leads 83 and being located in region 81 to sense the
temperature thereof, and the other resistors being inappreciably
susceptible to resistance change with variation in temperature (or
being maintained at constant temperature). The bridge output is
transmitted via pair of leads 85 to Controller 86, which is
supplied with electrical potential E2 via pair of leads 87 and
which controls the temperature of region 81, in response to the
bridge output, by means of heating element RH located in that
region and connected to the controller via leads 88.
Instead of being a resistor the heating element may be suitable
radiant (or other) heating means and the leads thereto be suitable
piping, the controller controlling the flow of heating fluid
through the piping in conventional manner as it can control the
flow of heating electrical current. Further details of the
controller and its connection into the circuit are omitted for
simplicity, being obvious to persons having an understanding of the
pertinent art.
FIG. 13 shows, also schematically, cooling region 91, which may
constitute (or by part of) Cooling Zone 26. It is provided with
temperature-sensitive resistor or thermistor R5 located therein and
having pair of leads 93 to a bridge (not shown) by analogy to the
similar elements of the immediately preceding view. Cooling element
RC also located in region 91 has pair of leads 98 to a controller
(not shown), the further analogy with the apparatus of FIG. 12
being apparent. The cooling element may be either a thermoelectric
element or a refrigerating coil (in which instance leads 98 would
be piping), for example. As suggested above a cooling element might
be useful in Intermediate Zone 25 as well, such as near (inside)
the entrance to the stuffing chamber where the applied longitudinal
compression and resulting buckling or columnar collapse of the yarn
or strand generates undesired heat, as may friction with the feed
rolls or the chamber entrance itself.
With suitable insulation of the Heating, Intermediate, and Cooling
Zones, such apparatus permits accurate control of the temperature
thereof. The respective zones should be sufficiently large, as
compared with the rate of travel of the strand therethrough, to
hold the strand for a long enough time to have the desired effect
upon it. Temperature-sensing means may be provided at locations W,
X, Y, Z, as suggested above, or at other convenient locations to
ensure accurate determination of temperature, together with
temperature-controlling means as may be required for the desired
temperature control. Insulation of the Intermediate Zone, which
contains the crimping means, from the other two zones may suffice
to ensure adiabatic conditions therein. However, if that does not
suffice to maintain the strand at essentially constant temperature
therein, and especially while it is under crimping stress, one or
more controllers (with heating or cooling elements, or both) may be
employed as in the other two zones.
While various embodiments of this invention have been disclosed,
other modifications may be made, as by adding, combining, or
subdividing parts or steps, while retaining significant benefits
and advantages of the invention, some of which have been mentioned
and others of which will become apparent to those undertaking to
practice the invention in accordance with the foregoing teaching.
The invention itself is defined in the following claims.
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