EP0201357A2

EP0201357A2 - Vacuum spinning of fasciated yarn

Info

Publication number: EP0201357A2
Application number: EP86303567A
Authority: EP
Inventors: Danny R. Bradley; N. Page Hardy; Elbert Flemming Morrison; D.C. Reece
Original assignee: Burlington Industries Inc
Current assignee: Burlington Industries Inc
Priority date: 1985-05-09
Filing date: 1986-05-09
Publication date: 1986-11-12
Anticipated expiration: 2006-05-09
Also published as: EP0201357B1; EP0201357A3; DE3680706D1; CN1021065C; JPS61275435A; JPH07100886B2; CA1317169C; BR8602073A; KR860009164A; CN86103633A

Abstract

A fasciated yarn suitable for making apparel fabric and having properties approaching that of ring spun yarn is produced by vacuum spinning, including directly from sliver. An elongate hollow shaft (20) of the vacuum spinning apparatus has a vacuum reservoir (32), or interior chamber, that is generally in the shape of a right circular cone, and the interior passageway (31) of the shaft from the first end (21) thereof to the interior chamber can have the form of a right circular cone frustum. Perforations (40) operatively connected to the interior chamber have a generally wedge-shape. The perforations and the passageway sections between the first end of the shaft and the perforations are dimensioned so that they allow sufficient air flow to achieve optimum fiber wrapping action. Initial threading of the vacuum spinning apparatus is provided by a vacuum tube (745) mounted for rotation about an axis parallel to and spaced from the axis of rotation of the shaft, the vacuum tube being connected up to a vacuum reservoir (742) and source of vacuum (728) and rotatable from an inoperative to an operative position.

Description

This invention relates to the vacuum spinning of fasciated yarn. In US-A-4507913 there are disclosed methods and apparatus for efficiently and effectively producing yarn having properties approaching those of ring spun yarn, but at much greater speeds. The basic technique disclosed in the patent is known as "vacuum spinning", and has a number of advantages compared to conventional techniques.
Until relatively recently, ring spinning equipment has made up approximately 90 percent of all spinning equipment. However several new high speed procedures have recently been utilized including open end spinning, friction spinning, hollow core spinning, and air jet spinning. None of these new commercial systems has been succesful in the production of long staple yarn, however, especially for apparel fabrics. However vaccum spinning is capable of producing long staple yarn suitable for use in apparel fabrics, the yarn approaching the properties of ring spun yarn.
Vacuum spinning has a number, of advantages compared to conventional ring spinning. These include the following. Productivity can be expected to be at least 6-8 times that of commercial ring spinning. Despite this increased productivity, the properties of the yarn are more like ring spun yarn than open end air jet type yarns. The horsepower per pound of yarn produced is considerably less than that for air jet spinning using compressed air.
Vacuum spinning lends itself to automatic end piece-up, automatic slubbing, automatic adaptation, the production of large delivery packages, and the utilization of large supply packages (e.g. 25 lb. (11 kg) cans of sliver). A wide count range can be provided on long staple yarns, at least 1/8's to 1/60's on 55 percent polyester/45 percent wool, and at least 1/8's to 1/40's on 100 percent wool. There are lower labour costs per kilogramme of yarn produced compared to ring spun yarn.
According to this invention there is provided apparatus for forming yarn, comprising an elongate hollow shaft having a first end and a second end, a through-extending passageway from the first end to the second end, at least a portion of the entire circumference of the shaft being perforated by perforations; means for mounting said shaft for rotation about an axis; means for rotating said shaft about its axis; means for passing textile fibers through the through-extending passageway of said shaft linearly, generally along the axis of rotation thereof, the fibers being fed into the first end thereof; means for applying a vacuum to the exterior of said shaft so that at least some of the fibers or free ends of fibers passing through said shaft will draw toward the perforations and will be caused to rotate with said shaft as said fibers move linearly generally along the axis of rotation; means for withdrawing formed yarn from the second end of said shaft, opposite said first end thereof, characterised by means provided between the first end and second end of said shaft for allowing free fiber movement so that at least some of the fibers or free ends of fibers adjacent said perforations will rise up and wrap around a core of fibers as the fibers pass through the passageway.
Also according to this invention there is provided a method of spinning yarn comprising the steps of drafting a sliver of fibers so as to produce a drafted sliver; and feeding the drafted sliver in a linear direction A in a fiber mass, characterised by the steps of passing the fiber mass into the interior of a hollow shaft rotatable about an axis generally coincident with the direction A, the shaft having perforations along the circumference of a portion thereof, and having an enlarged interior chamber at the perforations; applying a vacuum to the circumferential exterior of the perforated portion of the shaft sufficent to attract some of the fiber mass inside the shaft toward the shaft interior surface; and rotating the shaft at high speed so that the ends of certain of the fibers interior of the shaft rotate with the shaft as they are moving in the direction A and so that those ends extend into the enlarged interior chamber so as to ultimately wrap around other portions of the fiber.mass, to produce a final yarn.
Advantages of the invention are that it lends itself to high draft ratios (e.g. 10-80); it can be modified to run both long and short staple yarns; and it can make yarn having either "S" or "Z" twist. A number of unique novelty yarns can be produced. The apparatus is simple and easy to maintain, and the noise level can be controlled by locating the vacuum pump in a separate location, to thereby ensure compliance with OSHA regulations. The apparatus runs cleanly since the vacuum automatically removes lint fly, and like contaminants, and oily waste is not introduced. Waste is reduced due to draft zone stoppage on end breaks, with a reduction in end breakage of about 400 percent compared to ring spinning since there is no tension in the yarn. Also thread-up of the broken ends can be accomplished with minimum operator intervention. The apparatus can be run using higher weight sliver (e.g. 55 grains per yarn compared to 35-40 grains per yarn which is conventional), and carpet yarn can be produced too by lengthening the draft zone and providing a larger nozzle. Yarn steaming may not be required for most counts-blends for handling, although it may be required for uniform dyeability, and steaming is easy to effect.
The yarn produced by the apparatus and method of the present invention includes core fibers and wrapper fibers. The wrapper fibers are predominantly individual fibers, although there are some groups of wrapper fibers. The groups of wrapper fibers appear as non-uniform, non-consistent fiber groupings, and provide a relatively smooth surface. The core fibers, on the other hand, are essentially parallel with the wrapper fibers uniformly distributed therearound. The fasciated yarn thus looks most like ring spun yarn of the commonly known yarns, although it is distinct in appearance from ring spun yarn too. For instance the yarn looks more like ring spun yarn than core spun, open-end, Murata jet spun, Toray, or DREF II prior art yarns.
The fasciated yarn as set forth above, includes essentially parallel core staple fibers. There is a uniform distribution of staple fiber wrapper fibers aroung the core fibers, the wrapper fibers being wrapped at a helix angle of about 30°, and with about 20-30 percent of the fiber mass comprising wrapper fibers.
The fasciated yarn can also be described as a yarn having a core of essentially parallel staple fibers with the wrapped staple fibers disposed around the core forming a helix angle in the range of about 30-50⁰, and the wrapped fibers are devoid of tucked or reverse wrapped fibers and are essentially devoid of auger or corkscrew appearing wrapped fibers. Rather the wrapped fibers have a smooth appearance.
The fasciated yarn can be produced with the predominant proportion of staple fibers of the core and covering as non-thermoplastic staple fibers. While the predominant proportion of the core and wrapped fibers can be selected from the group consisting of cotton, wool. rayon, mohair, flax. ramie, silk and blends thereof, the yarn also can be constructed using some, or all, thermoplstic fiber, such as acrylic, polyester, and other thermoplastic fibers or blends thereof.
The yarn produced by the apparatus and method of the present invention has surprising and desirable strength. For instance yarn produced from a 1/18's count of 45 pecent polyester and 55 percent wool will have a minimum gram break strength of about 500, while yarn with the same count made of 100 percent wool will have a minimum gram break strength of at least about 175. Thus, even when made from 100 percent wool the yarn is suitable for making apparel fabrics.
The apparatus and method acccording to the present application also have basically all the same advantages described about with respect to vacuum spinning in general. Additionally, in the production of yarn from roving it is possible to construct the "nozzle" of the vacuum spinning apparatus in a simpler and more advantageous manner. By providing an interioir generally conically shaped vacuum resevoir, instead of a spherical vacuum reservoir, ease of production is faciliated and a yarn having a slightly better break strength can be produced.
Further, the production of yarn directly from sliver is facilitated.
The particular "nozzle" for producing yarn having good strength properties directly from sliver, preferably includes a generally conically shaped interior chamber. The perforations in communication with the interior chamber are generally wedge-shaped, and the size of the interior passageway in the shaft adjacent the first end thereof is very large compared to the diamter of the shaft passageway betwenn the interior chamber and the second end of the shaft, and may have the shape of a right circular cone frustum. The interior chamber is dimensioned so that it is large enough to allow free fiber movement so that the fibers will be lifted up and wrap around a core of the fiber mass more securely; however the interior should not be so big the the fibers will be pulled through the perforations by the vacuum source. The perforations and the passageway between the first end of the shaft and the perforations, are dimensioned so that optimal wrapping action can be achieved. That is, the dimensions are large enough so that they allow sufficient air flow that they do not prevent the attainment of optimal fiber wrapping action. In this way optimal wrap for any given application may be achieved.
While vacuum spinning is a generally low maintenance procedure, during the initial start up there are difficulties in threading the fibers through the shaft passageway to the take-up mechanism. The procedure is not self-starting, and typically has been accomplished in the past by using a thread-up wire attached to the end cf the fibers and manually pushing and pulling the thread-up wire through the passageway until the fibers were completely through the passageway. Then the fibers were wrapped around a take-up cone, or like take-up mechanism.
The apparatus and method of the present invetion greatly facilitate the initial threading of a vacuum spinning system elongate hollow shaft. Initial threading can be provided in an efficient semi-automatic preocedure utilizing a vacuum tube mounted for rotation with respect to a vacuum reservoir so that the second end of the tube is movable from a first, inoperative, position wherein it is spaced from the opening, to a second, operative, position wherein it is in operative communication with the opening so that a vacuum is drawn through the tube first end into the reservoir and to the source of vacuum. The axis of rotation of the tube is generally parallel to the axis of rotation of the elongate shaft of the vacuum spinning apparatus, so that when the tube is rotated into its second, operative, position, the first end of the tube is immediately adjacent the second end of the elongate shaft so that it sucks the connected fibers within the shaft all the way through to the end thereof. Preferably means are provided responsive to rotation of the vacuum tube from its first to its second positions for cutting out the vacuum applied to the exterior of the elongate shaft when the vacuum tube is moved toward its second position.
The invention will now be described by way of example with reference to the drawings, in which:-

Figure 1 is a microphotograph at approximately 70x magnification of vacuum spun yarn produced according to the present invention;
Figure 2 is a microphotograph of the same yarn as Figure 1 only at a magnification of 35x;
Figures 3 through 8 are microphotographs of other, conventional, spun yarns made respectively by core spinning, open-end, ring spun, MJS, Toray, and DREF II techniques respectively;
Figure 9 is a side view of exemplary apparatus according to the present invention, shown in schematic cooperation with a vacuum source and feed roller;
Figure 10 is a side cross-sectional view of an exemplary "nozzle" for use with the apparatus of Figure 9;
Figures 11 through 18 are side schematic cross-sectional views of exemplary other forms of "nozzles" that may be utilized in vacuum spinning procedures;
Figure 19 is a side schematic view showing conventional vacuum spinning apparatus in elevation, and showing a portion of a vacuum tube of exemplary apparatus according to the invention in operative association with the vacuum spinning apparatus;
Figure 20 is a side cross-sectional view of an exemplary vacuum spinning elongate hollow shaft showing a first end of an exemplary vacuum tube in operative association'with the vacuum apparatus shaft;
Figure 21 is a front perspective view of exemplary threading apparatus of Figures 19 and 20;
Figure 22 is a rear perspective exploded view with portions cut away for clarity of the apparatus of Figure 21; and
Figure 23 is a top plan schematic view of the apparatus of Figures 21 and 22 mounted in position with respect to the vacuum spinning apparatus of Figure 19.

The basic vacuum spinning apparatus 14 illustrated in Figure 9 is similar to that shown in US-A-4507913. The apparatus 14 comprises an outer housing 16, of metal, ceramic, or the like, which is operatively connected up through integral nipple 17 to a vacuum source 18, such as a vacuum pump which provides 20 inches of mercury at 19 cfm (or more). The interior of the housing 16 is hollow. The interior "nozzle" of the apparatus 14 is indicated generally by reference numeral 20, and includes a first end 21 thereof and a second end 22. At the second end 22 a gear 24 is mounted, which is connected to appropriate other gears and drives (not shown) for effecting rotation of the "nozzle" 20. The drives can rotate the "nozzle" 20 either clockwise or counterclockwise to provide either a Z or S twist, as desired.
From a draft system (not shown) a sliver S passs through the nip of the front feed rolls 26, and the produced yarn Y exits from the second end 22 of the apparatus 14.
A "nozzle" 20 for the production of yarn from sliver is shown in detail in Figure 10. The "nozzle" 20 comprises an elongate hollow shaft 30 having a first end 21 and a second end 22. A through-extending passageway goes from the end 21 to the end 22. The passageway includes a first portion 31 adjacent the first end 21, an interior chamber portion 32 close to, but spaced from, the first end 21, and a third portion 33 that extends from the portion 32 all the way to the second end 22. In the specific embodiment illustrated in Figure 10, the diamteter of the portion 33 is 1/16th of an inch, and is substantially constant.
Mounting the shaft within the casing 16 for rotation preferably bearings 35, 36 are provided. An annular shaped flange 37 extends outwardly from,, and is integral with, the shaft 30 adjacent the end 22 and the bearing 36 abuts the flange 37. The exterior cylindrical surface 38 of the shaft 30 the gear 24 is press-fit so that rotation of the gear 24 effects rotation of the shaft 30.
The shaft 30 illustraded in Figure 10 is one that is particularly adapted for forming yarn Y from a sliver, rather than from a roving. The production of yarn directly from sliver, instead of from roving of course has a number of advantages since it essentially eliminates a step (and the associated equipment for performing the step) in the yarn formation process. It has been found that in the production of yarn from sliver, instead of from a roving, it is necessary to maximise the air flow from the first end 21 to the vacuum source 18, while still providing a restricted enough path for the movement of the fibers so that they are not pulled out of the shaft 30 by the vacuum. In the specific embodiment illustrated in Figure 10, this maximized air flow is provided by making the dimensions of the first passageway section 31 very large compared to the section 33, and providing perforations 40 that have a total effective area generally comparable to the effective operative area of flow in the passageway section 31, so that optimum wrap of fibers is achieved.
The passageway section 31 is substantially circular in cross- section, and for the embodiment illustrated in Figure 10 has a diameter of about 0.387 inches, with the outside diameter of the shaft 30 at that point being about 0.5 inches. The intermediate portion 32 of the passageway has a generally conical configuration, in essence having the configuration of a right circular cone. The passageway portion 32 is dimensioned so that it comprises a means for allowing free fiber movement therewithin, so that the fibers can be lifted up a substantial distance to wrap around the core during the production of the yarn Y from sliver S. For the particular structure illustrated in Figure 10, the passageway sections 31, 32 may be formed as follows:

-Using a number 4 center drill, then end 21 is concentrically penetraded to a depth of about 0.51 inches.
-Using a 15/64 inch drill, the end 21 is concentrically re-penetrated to the depth of about 0.497 inches.
-Using a 1/4 inch end mill, the end 21 is again concentrically penetrated to a depth of about 0.42 inches.
-Using a 3/8 inch 60⁰ countersink, the end 21 is again concentrically penetrated to a depth of 0.52 inches.

Passageway section 33 if formed merely by concentrically penetrating the end 22 with a 1/16 inch drill, and drilling all the way to the preformed passageway portion 32. Typical other dimensions of the shaft 30 are as follows: the distance 42 equals about 3/8 inch; the diameter of the end 22 is about 0.503 inches; the thickness of the flange 37 is about 0.125 inches; the diameter of the portion recieving the bearing 36 is about 0.501 inches; and the length of the shaft 30 from the begining of the flange 37 is about 1.5625 inches.
Note that there is a tapered wall portion between the passageway section 32 at the perforations 40 and the passageway section 33; this tapered wall portion being illustrated by reference numeral 44 in Figure 10. The provision of this tapered wall, compared to the same configuration of the shaft 30 without the tapered wall; leads to significantly better results.
For the embodiment illustrated in Figure 10 the perforations 40 are preferably four in number, and are evenly spaced around the periphery of the shaft 30. Each perofration 40 is generally wedge-shaped. The width of each of the perforations 40 at the exterior surface of the shaft 30, which width is indicated generally by reference numeral 46, is about 34 inches. Each of the perforations 40 is formed by drilling an opening from the circumference to the passageway section 32 with a 3/32 inch drill at about a 34° angle, and then reaming to the vertical to form the surface 48 which is essentially perpendicular to an extension of the passageway third portion 33. The results achieved by providing the face 48 generally perpendicular to the passageway section 33 are significantly improved compared to the situation where the 3/32 inch hole is drilled at a 34⁰ angle and there is no reaming.
Other illustrative configurations of nozzles which may be utilized according to the present invention are illustrated in Figures 11 through 15. While all of these nozzles are useful in forming yarn, it will be seen from the comparative test results for these nozzles that some produce yarn having significantly better properties than others.
The nozzle 120 illustrated in Figure 11 has a generally constant 1/8 inch diameter through-extending passageway 133, with four rows of 1/16 inch diameter perforations 140 each at a 90⁰ angle to the passageway 133.
The nozzle 220 in Figure 12 has a constant 1/8 inch diameter through-extending passageway 233 with four perforations 140 each 1/16 inch in diameter and angled in the direction of the second end 222.
The nozzle 320 illustrated in Figure 13 has a passageway portion 333 comunicating with the second end 322 thereof that is 1/16 inch in diameter. Adjacent the first end 321 thereof the passageway portion 331 is about 1/8 inch in diameter. Between the passageway portions 331, 333, is a 1/4 inch diameter spherical vacuum reservoir 332, with four 1/16 inch diameter angled perforations 340 extending outwardly from the reservoir 332.
The nozzle 420 of Figure 14 has a passageway portion 433 that is 1/16 inch in diameter, and a passageway portion 431 which is 1/8 inch in diameter. The passageway portion 432,may be considered a vacuum reservoir, and has a conical shape. Four 1/16 inch angled perforations 440 are provided in communication with the reservoir 432.
The Figure 15 nozzle 520 is essentially identical to the nozzle 20 illustrated in Figure 10 (note that the showing in Figure 15-is schematic), except that the entire passageway section 531 has the shape of a cone frustum, and the shape of the passageway section 532 --- and the exact points that the perforations-40 come off of it --- are slightly different.
The nozzles illustrated in Figures 11 through 14 are suitable for use in forming yarn from roving, but do not form particularly strong or useful yarns from a sliver. However the nozzles 520 of Figure 15, and 20 of Figure 10, are capable of forming strong yarns from sliver, having an increased total air flow from the first end thereof through the perforations to the vacuum source 18. Also the middle sections of the passageways (32,532) allow free fiber movement so that the fibers will be lifted up and wrap around the core more securely., However the passageways 32, 532 are not so big that the fibers will be pulled through the perforations 40, 540 by the vacuum from source 18. Also in these embodiments the perforations collectively have effective cross-sectional areas relative to the effective cross-sectional area of the passageway section between the first end of the shaft and the perforations so that the dimensions of the perforations and passageway section are not a limiting factor in attaining optimal wrapping action of the fibers. In this way optimal wrap for any given application may be achived.
The following Table I gives the results of tests that have been done on the nozzles of Figures 11 through 15 utilizing the same composition of feed materials. In each case 1/19's poly/wool feed fibers were utilized, 55% 3dx3 1/2"x4 1/2" T-655 Dacron Natural (polyester), and 45% WP644 Wool Natural. The vacuum source 18 in each case applied a vacuum of about 14-15 inches of mercury, but the volume of air flow was significantly greater for the Figure 15 embodiement than for the other embodiements.
Surprisingly, the breaking strength of the yarn produced by the nozzle of Figure 15 directly from sliver was greater than the breaking strength of the yarn produced from roving utilizing the nozzle of Figure 14 (which is similar in construction to that of Figure 15). Note that the nozzles of Figures 11 through 13 are suitable for use with a diffuser, while those of Figures 14 and 15 are not designed for use with a diffuser.
Note also that the generally conically shaped passageway section (vacuum reservoir) 432 of the Figure 14 nozzle achieves a yarn of higher break strength than for the spherical vacuum reservoir 332, 432 also have other functions, such as providing a chamber (volume) for raial deflection of the fibers so that the wrapping function is facilitated.
The apparatus according to the present invention thus includes an elongate hollow shaft 30 having first end 21 and a second end 22, with a through-extending passageway 31, 32, 33. A least a portion of the entire circumference is perforated, by perforations 40. Means for mounting the shaft for rotation comprise the bearings 35, 36 and the housing 16 and means for rotating the shaft.about its axis comprise the gear 24 and associated powered components (not shown). The feed rolls 26, and other components, comprise means for passing textile fibers S through the passageway 31-33 of the shaft 30, linearly, generally along the axis of rotation thereof, the fibers being fed into the first end 21. The source 18 applies a vacuum to the exterior of the shaft 30 so that at least some of the fibers are free ends of fibers passing through the shaft will draw toward the shaft perforations 40, and will be caused to rotate with the shaft as the fibers move linearly generally along the axis of rotation, the passageway portion 32 allowing sufficient volume for the fibers to lift and wrap around the core. Withdrawing rollers , or like conventional components are provided as means for withdrawing the formed yarn Y from the end 22. Utilizing the embodiment illustrated in Figures 10 and 15, it is possible to make yarn having properties approaching that of ring spun yarn directly from sliver.
In tests run utilizing the nozzles of Figures 16 through 18 respectively, with different blends and worsted counts of yarn, the following results were obtained (all results plus or minus E and "SS" means "short staple"):

As can be seen from the test results, the yarn produced according to the present invention has a break strength comparable to a break strength of at least 500 gram break strength denier for a yarn produced from 1/18's count fibers of 55 percent polyester and 45 percent wool. Tests were also conducted utilizing a nozzle like that of Figure 17 only having the actual chamber construction like that of chamber 646 of Figure 18. In such tests, when yarn with a blend of 45 percent polyester and 55 percent wool was spun from sliver with a count of 1/18's the gram break strength was 518 and the elongation 8.4 percent. When spun from 100 percent wool sliver with the same count the gram break strength was 248 and the elongation 14.1 percent. Thus by practicing the invention, too, it is possible to produce yarn having sufficient strength to be used as an apparel fabric from non-thermoplastic staple fibers.
Note that the nozzle 620 of Figure 16 has a passageway portion 624 communicatinf with a second end thereof, and a passageway portion 621 communicating with a first end thereof. Between the passageway portions 621, 624 a 1/4 inch diameter spherical vacuum reservoir 622 is provided with four 1/16 inch diameter angled perforations 623 extending outwardly from the reservoir 622.
In Figure 17, the nozzle 630 has a first passageway section 631 that has the shape of a cone frustum and a second passagway section 634 that is comparable to the passageway 624 of the
Figure 16 embodiment. It also has an intermediate passageway portion 632 that may be considered a vacuum reservoir, which has a conical shape, with four 1/16 inch angled perforations 633 in communication therewith.
The nozzle 640 of Figure 18 includes the first conical passageway portion 641, a second portion 644 comparable to the passageway portion 624 of the Figure 16 embodiment, and a pair of passageway portions 642, 646 each which are generally conical in shape and have four 1/16 inch angled perforations 643, 647, repectively extending outwardly therefrom.
Viewing the vacuum spun yarn illustrated in Figures 1 and 2, it will be seen that a fasciated yarn is provided consisting of staple fibers including core fibers and wrapper fibers. The wrapper fibers are predominantly individual fibers although there are some groups of wrapper fibers. The groups of wrapper fibers appear as non-uniform, non-consistent fiber groupings and provide a relatively smooth surface. The core fibers are essentially parallel with the wraper fibers uniformly distributed therearound. The core fibers have the same dyeability as the wrapper fibers.
Another way that the yarn of Figures 1 and 2 can be described is a fasciatd yarn having essentially parallel core staple fibers and having a uniform distribution of staple wrapper fibers around th core fibers. The wrapper fibers are wrapped at a helix angle of about 30° (e.g. within the range of about 30-50°), and about 20-30 percent of the fiber mass comprises wrapper fibers. The wrapped fibers are devoid of tucked or reverse wrapped fibers and are essentially devoid of auger or corkscrew appearing wrapped fibers, rather having a smooth appearance.
Comparing the vacuum spun yarn of Figures 1 and 2 to the conventional spun yarns of Figures 3 and 5 through 8, it will be seen that the vacuum spun yarn of Figures 1 and 2 has an appearance closest to that of the ring spun yarn of Figure 5.
Note that the core spun yarn of Figure 3 has core fibers which are parallel with a filament yarn twisted (a true twist) around the mass of yarn for strength. This is not a fasciated yarn.
The open end yarn of Figure 4 also has true twist, with a surface dotted with wrapper fibers loose around the mass. Again this is not a fasciated yarn.
The MJS air spun yarn of Figure 6 is the next closest to ring spun yarn (that is next closest with vacuum spun yarn being the closest) of the known spun yarns. The MJS yarn has fibers wrapped at approximately a 55° angle showing a small amount of twist in the core fibers. The percentage of wrapped fibers is approximately 10 percent. The wrapper fibers are more or'less in the form of individual fibers.
The Toray yarn of Figure 7 has wrapper fibers which are disposed at approximately a 45° angle and appear to be buried deeper into the core fibers than for the other yarns, causing a corkscrew appearance. The surface fibers tend to be tangled in the fiber mass similar to Taslan yarns. Approximately 20 percent of the fibers are wrapped surface fibers. The auger or corkscrew look of the Toray yarn is vastly different than the smooth appearance of vacuum spun yarn.
The DREF II yarn of Figure 8 is friction spun yarn with true twist and without any surface wrapped fibers. This yarn is also not a fasciated yarn.
It is noted that the fasciated yarn can be made from 100 percent non-thermoplastic staple fibers. That is at least the predominant portion of the staple fibers forming the fasciated yarn can be selected from the group consisting of cotton, mohair, flax, ramie, silk, wool, rayon, and blends thereof. However the fasciated yarn is not restrticted to non-thermoplastic fibers, but also can be produced from, or from blends of (with non-thermoplastic fibers) acrylic, polyester, and other fibers.
Note that vacuum spun yarn has many differences compared to-other known fasciated yarns. Some properties of vacuum spun yarns that are not true of all other fasciated yarns are as follows: Vacuum spun yarn does not require thermoplastic fibers, the wrapped fibers can be the same as the core (not fused by heat), the yarns will dye the same since the molecular structure thereof is not changed (the core and surface fibers have the ame dyeability),and the wrapped fibers are laid parallel and not looped over each other in a non-uniform pattern.
The apparatus and method described above provide a yarn suitable for making apparel fabric, comprising a fasciated yarn which has good strength and appearence properties, and most closely simulates ring spun yarn, yet which can be produced at much higher speed than ring spun yarn and with fewer steps. For instance in ring spinning long staple yarns, first the staple fibers are blended, gilled, combed, gilled four times, used to produce a roving, spun, wound, and then put to an end use. Vacuum spun yarn of the other hand, made form long staple fibers is produced as follows: the fibers are blended, gilled, combed, gilled three times, vcuum spun, and then put to the end use. Thus three less steps are used in vacuum spinning long staple fibers compared to ring spinning long staple fibers. In vacuum spinning short staple fibers, the same number of steps are used as for air jet spinning short staple fibers, namely blending, carding, drawing twice, spinning, and putting to an end use.
The invention also contemplates a vacuum mechanism for threading the vacuum spinning apparatus, which can be seen in Figures 19-23.
With reference to Figures 19, 20 and 23, conventional components of the vacuum spinning apparatus 714 include the housing 716 and an elongate hollow shaft 718 having a first end 719 thereof and a second end 720, with a through-extending passageway 721 (see Figure 20) from the first end 719 to the second end 720. At least a portion of the circumference of the shaft 718 is perforated, as by perforations 722 (see Figure 20), which typically would comprise four perforations equally spaced around the circumference of the shaft 718. The shaft 718 is mounted for rotation about an axis A-A, as by bearing means (shown schematically at 724 in Figure 20) extending between the shaft 718 and the housing 716. The housing 716 is connected up, through conduit 726 and valve 727 (see Figure 19) to a source of vacuum 728, such as a conventional vacuum pump. The shaft is rotated about the axis A-A by a motor 729, or like power source, which is operatively connected to that shaft 718 through gear 730 or a like standard drive structure such as a pulley or sprocket.
In typical use of the vacuum spinning apparatus 714, drafting apparatus (not shown) nips a sliver or roving S and feeds the textile fibers of the sliver or roving S (including through a set of feed rolls 732) to the first end 719 of the shaft 718. The vacuum that is applied to the circumferential exterior of the shaft 718 causes an air flow from the first end 719, and through the perforations 722, so that at least some of the fibers or free ends of fibers passing through the shaft will draw toward the shaft perforations 722, and will be caused to rotate with the shaft as the fibers move linearly generally along the axis of rotation A-A. Operatively associated with the second end 720 of the shaft 718 is a conventional take-up mechanism, such as the take-up cone 734 shown schematically in Figures 19 and 23.
The threading apparatus is shown generally by reference numeral 740 in Figures 21 through 23. A first major component of the apparatus 740 is the vacuum reservoir 742, which has walls including a front end wall 744. The reservoir 742 is operatively connected to the cource of vacuum 728, as through a conventional conduit means 743.
The second major component of the apparatus 740 comprises a vacuum tube 745. The vacuum tube has an open first end 746, and an open second end 747.
The apparatus 740 also comprises means for defining an opening 749 in the reservoir wall 744, and means for mounting the tube 745 for rotation. In the exemplary embodiment illustrated in the drawings, the means for mounting the tube 745 for rotation comprises the cylinder 750 having a shaft 751 extending outwardly therefrom generally parallel to the second end 747 of the vacuum tube 745, and concentric with the cylinder 750. The shaft 751 passes through bearing opening 753 in the reservoir wall 744, and the free end of the shaft 751 is held within the reservoir 742 by the E-clip 754, or a like attachment mechanism. The vacuum tube 745 has a substantially straight central portion 756, a first end portion 757 which contains the first end opening 746 and which is generally perpendicular to the portion 756, and a second end portion 758 containing the second end opening 747 which is also generally perpendicular to the central portion 756 and generally parallel to the first end portion 757. The second end portion 758 is mounted within the cylinder 750 so that it is off-center; i.e. so that the second end opening 747 is radially spaced from the shaft 751, as seen in Figure 22.
The cylinder 750, shaft 751, bearing opening 753, and like components comprising means for mounting the tube 745 for rotation, mount the tube 745 for rotation with respect to the vacuum reservoir 742, about the axis B-B, so that the tube 745 is moved from a first, inoperative, position (see Figures 21 through 23) wherein it is not in operative communication with the reservoir 742, to a second, operative position (dotted line position in Figure 22, and the position shown in Figures 19 and 20) wherein it is in operative communication with the reservoir 742 due to the fact that the second end opening 747 of the vacuum tube is aligned with the opening 749 in the vacuum reservoir wall 744. In the operative position, the vacuum pulled by vacuum source 728 causes air flow through the first open end 746 of the vacuum tube 745, all the way through the vacuum tube 745, and through the opening 749 into the reservoir 742, and then ultimately through conduit 743 to the vacuum source 728.
Suitable stop mechanisms (not shown) may be provided on the cylinder 750 and the vacuum reservoir 742 to stop the rotation of the vacuum tube 745 in the operative position wherein the openings 747, 749 are aligned. Additionally, spring means (not shown), such as a torsion spring connected betwee the shaft 751 and the reservoir wall 744 within the reservoir 742, may be provided to bias the tube 745 to its inoperative position.
It is also highly desirable to prevent a vacuum from being applied to the circumferential exterior of the shaft 710 when the vacuum tube 745 is in its operative position. In its opertive position the first open end 746 thereof is immediately adjacent the second end 720 of the shaft 718 and in alignment with the passageway 721, as illustrated in Figures 19 and 20. The cut-out of the application of the vacuum source 728 to the housing 716 may be effected by operatively connecting the tube 745 to an electrical switch -- shown schematically by reference numeral 761 in Figure 19 -- that is responsive to the pivotal movement of the vacuum tube 745 from its inoperative positon to its operative position. The switch 761 may be a mercury switch mounted on the tube 45, a reed switch mounted within cylinder 750 and cooperating with a magnet associated with reservoir wall 744, or any of a wide variety of other commercially available structures. The electrical switch 761 is operatively connected to a source of electrical power 762, and to a conventional solenoid operator 73 for the valve 727.
In the exemplary embodiment schematically illustrated in Figure 19, when the tube 745 is moved to its operative position the switch 761 is closed, causing actuation of the solenoid operator 763 to move valve 727 to its closed position so that no vacuum is applied to the interior of the housing 716. When the tube 745 is moved back to its first, inoperative position, the switch 761 opens, deactivating the solenoid actuator 763, so that the valve 727 moves to its normal open position.
As illustrated in Figure 23, the axis of rotation B-B of the vacuum tube 745 is preferably mounted so that it is parallel to, but horizontally spaced from, the axis of rotation A-A of the hollow shaft 718. Also the vacuum tube 745 is mounted so that it does not interfere with the take-up cone 734, or like take-up mechanism.
In a typical operation of the threading apparatus, connected fibers F (see Figure 20) are fed into the first end 719 of the hollow shaft 718. Typically the connected fibers F would be roving or sliver itself, which may not have been subjected to a drafting operation. Once the fibers F are initially fed into the opening 719, the vacuum tube 745 is manually engaged by the operator and moved from its inoperative position (Figures 21 and 23 and the solid line position in Figue 22) to an operative position (Figures 19 and 20 and dotted line in Figure 22), tube 745 rotating about the shaft 51 and axis B-B so that the first open end 746 thereof is adjacent the second end 720 of the shaft 718, and in alignment with the passageway 721. In this position the tube 745 is operatively connected through openings 747 and 749, and vacuum reservoir 742, to the vacuum source 728, and the tube 745 sucks the connected fibers F so that a segment thereof is pulled all the way through the passageway 721 (see Figure 20). During the manual pivotal movemement of the tube 745 to its operative position the switch 761 is closed and the valve 727 closed in response to the switch closure.
Once a segment of the connected fibers F has been sucked completely through the passageway 721, the vacuum tube 745 is moved back to its inoperative position. Then the segment of connected fibers, a portion of which extends outwardly from the second end 720 of the shaft 718, is operatively connected to the take-up cone 734, or a like take-up mechanism.
The the motor 729 is started and the vacuum spinning operation utilizing the apparatus 714 begins.
In the vent of the necessity for a rethreading for an "ends down" situation, motor 729 may continue to drive the shaft 718 as rethreading is effected.

Claims

1. Apparatus for forming yarn, comprising an elongate hollow shaft (20) having a first end (21) and a second end (22), a through-extending passageway (31, 33) from the first end to the second end, at least a portion of the entire circumference of the shaft being perforated by perforations (40); means (35,36) for mounting said shaft (20) for rotation about an axis; means (24) for rotating said shaft (20) about its axis; means for passing textile fibers (26) through the through-extending passageway of said shaft (20) linearly, generally along the axis of rotation thereof, the fibers being fed into the first end (21) thereof; means for applying a vacuum (18) to the exterior of said shaft (20) so that at least some of the fibers (26) or free ends of fibers passing through said shaft (20) will draw toward the perforations (40) and will be caused to rotate with said shaft (20) as said fibers (26) move linearly generally along the axis of rotation; and means for withdrawing formed yarn (734) from the second end (22) of said shaft (20), opposite said first end (21) thereof, characterised by means provided between the first end (21) and second end (22) of said shaft (20) for allowing free fiber movement so that at least some of the fibers or free ends of fibers adjacent said perforations (40) will rise up and wrap around a core of fibers as the fibers pass through the passageway (31, 33).

2. Apparatus as claimed in Claim 1, characterised in that said means for allowing free fiber movement comprises means defining a generally conically shaped portion (31) of said passageway having larger cross-sectional area portions thereof closer to said first end (21) and smaller cross-sectional area portions thereof closer to said second end (22).

3. Apparatus as claimed in Claim 2, characterised in that said conical portion (31) comprises a right circular cone having the center thereof in alignment with said first and second ends (21, 22) and said perforations are generally wedge-shaped and extend from said conical portion (31) to the exterior of said shaft (20).

4. Apparatus for forming yarn, comprising an elongate hollow shaft (20) having a first end (21) and a second end (22), a through-extending passageway (31,33) from the first end to the second end, at least a portion of the entire circumference of the shaft being perforated by perforations (40); means (35, 36) for mounting said shaft (20) for rotation about an axis; means (24) for rotating said shaft (20) about its axis; means for passing textile fibers (26) through the through-extending passageway of said shaft linearly, generally along the axis of rotation thereof, the fibers being fed into the first end thereof; means for applying a vacuum (18) to the exterior of said shaft (20) so that at least some of the fibers (26) or free ends of fibers" passing through said shaft (20) will draw toward the perforations (40) and will be caused to rotate with said shaft (20) as said fibers (26) move linearly generally along the axis of rotation; and means for withdrawing formed yarn (734) from the second end (22) of said shaft (20), opposite said first end (21) thereof, characterised in that said perforations (40) have effective cross-sectional areas relative to the effective cross-sectional area of said passageway (31, 33) between said first end (21) and said perforations (40) so that optimum fiber wrapping action is achieved.

5. A method of spinning yarn comprising the steps of drafting a sliver of fibers so as to produce a drafted sliver; and feeding the drafted sliver in a linear direction A in a fiber mass, characterised by the steps of passing the fiber mass into the interior of a hollow shaft (20) rotatable about an axis generally coincident with the direction A, the shaft (20) having perforations (40) along the circumference of a portion thereof, and having an enlarged interior chamber (32) at the perforations (40); applying a vacuum to the circumferential exterior of the perforated portion of the shaft (20) sufficent to attract some of the fiber mass inside the shaft toward the shaft interior surface; and rotating the shaft (20) at high speed so that the ends of certain of the fibers (26) interior of the shaft (20) rotate with the shaft (20) as they are moving in the direction A and so that those ends extend into the enlarged interior chamber (32) so as to ultimately wrap around other portions of the fiber mass, to produce a final yarn.

6. A yarn for use in making apparel fabric, characterised by; a central core of staple fibers substantially parallel to one another; and a covering of staple fibers which have one end imbedded in the core and the remainder wrapped around the core such that the wrapping portions of the covering fibers form a helix angle within the range of about 30-50⁰, the predominant proportion of staple fibers of the core and covering being non-thermoplastic staple fibers.

7. A fasciated yarn characterised in that it consist of staple fibers including core fibers and wrapper fibers, the wrapper fibers being predominantly individual fibers although having some groups of wrapper fibers, the groups of wrapper fibers appearing as non-unifrom, non-consistent fiber groupings, and providing a relatively smooth surface and the core fibers being essentially parallel with the wrapper fibers uniformly distributed therearound the wrapped fibers having the same dyeability.

8. A fasciated yarn characterised in that it has essentially parallel core staple fibers and uniform distribution of staple wrapper fibers around the core fibers, the wrapper fibers being wrapped at a helix angle of about 30° and with about 20-30 percent of the fiber mass comprising wrapper fibers, the fasciated yarn having an appearance closely approximating that of ring spun yarn.

9. A fasciated yarn characterised in that it has a core of essentially parallel staple fibers, and wrapped staple fibers disposed around the core, the wrapped staple fibers forming a helix angle in the range of about 30-50⁰; the wrapped fibers being devoid of tucked or reverse wrapped fibers, and being essentially devoid of auger or corkscrew appearing wrapped fibers, rather having a smooth appearance of wrapped fibers.

10. Vacuum spun yarn characterised in that it is composed of a plurality of predetermined fibers and fiber count, said yarn having a break strength close to the break strength of ring spun yarn made from the same predetermined fibers and fiber count, and having a break strength significantly greater than the break strength of open end spun yarn, having the same predetermined fibers and fiber count.

11. A threading apparatus comprising a vacuum reservoir (742) having walls (744); means (743) for connecting said vacuum reservoir to a source of vacuum (728); and means for defining an opening (748) in one of said reservoir walls (744), characterised by a vacuum tube (745) having a first (746) and a second (747) open end; and means (750, 749,.751, 747) for mounting said vacuum tube for rotation with respect to said reservoir so that said second open end of said tube is movable from a first, inoperative position wherein it is spaced from said opening to a second operative position wherein is is in operative communication with said opening so that a vacuum is drawn through said tube first end into said reservoir and to said source of vacuum.

12. Vacuum spinning apparatus comprising an elongate hollow shaft (718) having a first end (719) and a second end (720), a through-extending passageway (721) from the first end to the second end, and at least a portion of the entire circumference of the shaft being perforated (722); means (724) for mounting said shaft for rotation about a first axis; means (730) for rotating said shaft about its axis; means for applying a vacuum, from a vacuum source (728), to the exterior of said shaft to draw air through said first end of said shaft, and said passageway, through said perforations; means for feeding textile fibers (732) into said passageway from said first end of said shaft and means (734) for withdrawing form yarn from said second end of said shaft, characterised by a vacuum tube (745) having a first open end (746) thereof and mounted in operative association with said hollow shaft so that said vacuum tube is movable from a first inoperative position wherein the first open end thereof is spaced from said second end of said shaft, to a second, operative position wherein said first open end of said tube is adjacent said second end of said shaft, and in alignment with said passageway; and means (747, 740) for operatively connecting said vacuum tube to a vacuum source (728) when said vacuum tube is in its second, operative position.