Patent Publication Number: US-3877254-A

Title: Method and apparatus for knitting fabric from untwisted staple fibers

Description:
United States Patent [191 Walford [451 Apr. 15, 1975 METHOD AND APPARATUS FOR KNITTING FABRIC FROM UNTWISTED STAPLE FIBERS [75] Inventor: Richard L. Walford, Bloomfield,  
  [73] Assignee: J. P. Stevens &amp; C0., Inc., New York, N.Y.  
 [22] Filed: July 30, 1973 [21] Appl. No.: 383,856  
 [52] US. Cl 66/9 B [51] Int. Cl D04b 9/12 [58] Field of Search 66/9, 9 B, 125, 132; 19/150, 106  
 [56] References Cited UNITED STATES PATENTS 816,417- 3/1906 Ainley 19/150 3,254,482 6/1966 Stalego l9/l50 X 3,413,823 12/1968 Beucus et al.  
  FOREIGNPATENTS OR APPLICATIONS 1,387 8/1856 United Kingdom 19/106 Primary Examiner-Ronald Feldbaum Attorney, Agent, or FirmRobert Ames Norton, Esq.; Michael T. Frimer, Esq.; Saul Leitner, Esq.  
 [5 7 ABSTRACT A knitting machine, either circular or flat, is supplied with untwisted fibers which are moved by a carrier hook wheel across a shoe to form overlapping, hairpin-shaped loops which are then caught by the needle as knitting proceeds. The untwisted fibers may be supplied in the form of a sliver or roving or in the form of staple. In the latter case transfer mechanisms, including drive rolls and a brush, transfer and line up the staple at the point they are caught by the carrier hooks. Fabrics may be knit entirely of untwisted material or there may be associated with it a twisted staple or continuous filament yarn for additional strength and improved fabric recovery.  
 6 Claims, 6 Drawing Figures llllll PATENTED APR 1 EMS sum 2&#39; 955 FIG. 5  
 FIG. 2  
 lllll PATENTED APR 51975 saw u or 5 METHOD AND APPARATUS FOR KNITTING FABRIC FROM UNTWISTED STAPLE FIBERS BACKGROUND OF THE INVENTION There are two general broad types of knitting machine, warp knitting machines in which the stitches are formed of warps and machines which knit a single yarn one needle at a time. It is only with the latter general type of machine that the present invention deals.  
  Knitting machines which knit one needle at a time are also divided into two general types: circular knitting machines, in which the needles are around a circular periphery and which knit tubular fabrics, and flat knitting machines, which knit a flat fabric, Circular knitting machines may also be sub-divided into two general types: one where the needles remain stationary and the material feed and needle actuating mechanism, usually a type of cam. turn. and machines in which the needles move around and material feed and needle actuation remain stationary. These latter knitting machines have multiple. usually preorganized, material feed, whereas the type in which the needles remain stationary usually have a single supply of material or in the case of multiple materials. such as materials of different colors, the machine has to stop to doff the feeds from large packages on creels. On the other hand. movable supply of yarn requires large rotating creels, which would limit the number of feeds and moving feed actuating mechanisms present, together with progressive stopping of the machine. Of course, in the case of flat knitting, where in most machines a stationary creel is used, this can be programmed so that the machine would not need to be stopped for the doffing or changing of supply of packages. As different types of knitting machines, either circular or flat, are well known and, as far as needle actuation and actual stitch formation are not changed by the present invention, the invention may be considered as improvements in any of the well known types, the only changes required being material feed to permit knitting with untwisted material. Hitherto this has not been practical as no useful fabrics could be produced, and the improvements of the present invention make possible knitting fabrics of untwisted material.  
 SUMMARY OF THE INVENTION As has been pointed out above, the present invention permits knitting fabrics of untwisted material or of mixtures of untwisted material and twisted or continuous filament yarn. ln general this is effected by feeding the untwisted material in staple, sliver or roving form to a mechanism with carrier hooks which form the untwisted material into overlapping hairpin loops which are then transported to the needle being actuated, which hooks the hairpin loops and makes a stitch therewith. The hairpin loops are longer than the spacing between carrier hooks or other carrier mechanism, so that a number of hairpins overlap, very much as shingles on a roof. The knitting itself locks the loops together sufficiently so that a fabric of adequate strength is produced. Of course when knit fabrics are produced with both untwisted material and twisted or continuous filament yarn, as has been mentioned above, fabrics of even greater strength can be produced and have, for certain purposes, improved properties, such as elasticity of the fabric, recovery, so-called bounce, and the like.  
  The formation of the overlapping hairpin loops can be effected in various ways. The simplest and for most purposes the preferable way is a wheel or other moving element carrying hooks and a curved shoe adjacent to the moving carrier, and stationary, folds the individual loops into the form of hairpins and maintains them in this shape and with the extensive overlap which has been mentioned until the loops are caught by each needle as it makes its stitch. Any other mechanisms for achieving the result may be used, and therefore the present invention in its broadest process aspects is not limited to the preferred elements of a hook-carrying moving member&#39;and a shoe bearing against it.  
  It is also possible to make the hairpin-shaped loops, with or without one or more pretwisted or continuous filament laddering yarns, into a twisted or spun yarn. This is not literally the identical procedure as in ordinary spinning, but as it performs a similar result, the terms spinning&#34;and spinning mechanismwill be used in a broader sense to cover operations or equipment which cause the hairpin loops to wrap around either themselves or a laddering yarn. The terminology with respect to spinning will be adhered to throughout the remainder of this specification and is not intended to be limited to operations which are sometimes narrowly characterized as spinning. While .the hairpin loops can be spun in various spinning mechanisms, they must be suitable for the nature of the material. Thus, for example, certain types of break spinning would not be suitable. However, any mechanical spinning mechanisms which are suitable may be used, and the present invention is .not limited to any particular mechanical device. Preferably, in this aspect of the present invention a ringless twister or air spinner is used in which a yarn is spun by a tangential gas blast which forms loops similar to those formed in a skipping rope. These loops are very rapidly rotated and were first developed for already existing spun or continuous filament yarn and were designed for texturizing. This is described, for example, in the patents of Pike, US. Pat. Nos. 3,653,196, April 4, 1972; 3,700,391, October 24, 1972, and in two Pike application&#39;s, Ser. Nos. 213,274, filed Dec. 29, 1971, and 3 l4,070, filed Dec. I1, 1972. Both applications are assigned to the assignee of the present invention. In the Pike patents the rapidly rotating loops impart a false twist which then untwists. As described in the patents, the direction of the yarn during untwisting is abruptly changed. This results in texturizing. However, a further development of the Pike air texturizer in the two applications utilizes a movable rod which can be inserted various distances into the chamber in which the yarn loops are formed. In the two patents the change of direction is always outside of the chamber, but in the two applications it is inside provided that the rod is inserted part or all the way across the chamber, resulting in an abrupt change of direction as the false twist untwists. If the rod is completely withdrawn, or at least does not project into the chamber, then texturizing does not take place but there is a spinning or plying action. In the case of hairpin-shaped loops which can move over each other, this results in spinning, using the term, as has been stated above, in a broader sense. The only difference between spinning in a mechanical spinner or twister and in the Pike applications, which may be considered as ringless twisters, is that with the air spinners the wrapping around of the hairpin loop is from the inside out whereas in mechanical spinners, for  
 example those using the rings, it is from the outside in. In each case, however, a yarn is produced which has many of the properties of ordinary spun yarn, though under a microscope the structure is not completely identical. That is why the term spinningin the present specification is used in its broader sense and not in the sense of producing yarn which is identical with conventional spun yarn. Of course, whether a yarn is spun or texturized its bulk is increased, and this requires provision for overfeed, that is to say, the material going into the spinner must go in faster than it comes out as the bulked or spun yarn is thicker and hence shorter than the material entering into it. The air spinners of the Pike application have the great advantage that they are extraordinarily compact, much more so than any mechanical spinner. and so lend themselves readily to forming yarn from hairpin-shaped loops. Another practical advantage of the air spinners of the Pike application is that they can operate at very high speed with a minimum of vibration since there are no solid moving parts. The high operating speeds possible effect substantial operating savings. They also have the advantage that it is not necessary to start the feed as with many mechanical spinners or twisters. While a preferred yarn forming process of the present invention utilizes the Pike air twister, as far as the present invention is concerned, this air twister is not the invention of the inventor of the present application any more than are those known mechanical spinners which are suitable for handling the material,  
  Reference has been made to spinning a yarn in which there may be one or more pretwisted or continuous filament ladder yarns. When these are used, in general it is the hairpin-shaped loops which wrap themselves around the laddering yarn. However, where a laddering yarn is to be used, it is necessary to introduce the laddering yarn together with the hairpin-shaped loops through a single feed introducer into the air spinning mechanism. Therefore, when, as will be claimed in certain specific claims, spinning of the hairpin-shaped loops is recited, it should be understood that this part of the invention may be with or without laddering yarn. In every case, of course, the essential features of the present invention, that is the formation of hairpinshaped loops by a hooked wheel, which is the broadest feature of the present invention, must be present. It may be considered, therefore, that the formation of the hairpin-shaped loops must always take place. but then there are two ways in which this material may be used, either by direct knitting or by forming a spun yarn.  
  The present invention in its aspect of direct knitting of the hairpin loops, with or without a reinforcing yarn which itself is twisted or can be continuous filament, has a number of advantages. The first, and perhaps the most important single one, is that cost is greatly reduced because the operation of twisting staple fibers to form a yarn is eliminated but its function is not eliminated because the present invention with the overlapping hairpins of untwisted fibers produces knit fabrics of adequate structural strength. Another advantage of the present invention is that bulkier and softer fabrics can be produced by reason of the nature of the untwisted fibers, and for many purposes such fabrics are preferred. Where the bulkier and softer fabric is desired, the elimination of the operation of yarn formation by twisting not only does not eliminate its function but produces for the particular desired purpose an improved result, and this quality of fabric is produced regardless of whether or not there is knit with the untwisted fibers a twisted yarn or continuous filament for the additional strength, elasticity and other characteristics which are sometimes desired, as has been pointed out above. When this is done, the soft bulky nature of the fabric is not changed as a continuous filament or tightly twisted yarn when knit with the untwisted loops usually buries itself in the untwisted material so that the surface effect, feel, etc., is primarily or entirely determined by the untwisted material. If the auxiliary yarn, whether twisted or monofilament, had been knitted alone, it would knit continuously as in conventional knitting operations. In the present invention, however, the auxiliary yarn is only included when it is combined with the untwisted material of the hairpin loops of the present invention.  
  Since the present invention uses staple fiber, the nature of the fabric will depend extensively on the fiber, as is the case with spun yarns from such fibers. Many natural fibers, such as cotton, wool and the like, have rough surfaces, overlapping scales in the case of wool, whiskers in the case of cotton, and there is normally sufficient friction between individual fibers. Where, however, the staple is made of smooth fibers, for example thermoplastics such as polyethylene terephthalate, nylon, acrylics and the like, it is often necessary or desirable to crimp the fibers before they are cut into staple while the fibers are in the soft state, which crimping supplies the additional friction needed. Precisely the same considerations apply to untwisted fibers of the present invention. It is, however, an advantage that standard procedures for providing sufficient surface friction of the individual fibers of the staple may be used in the normal manner and it is unnecessary to pro vide for a special or different type of staple for use in the present invention. This eliminates special operations and retains the saving of the elimination of yarn formation without offsetting additional costs.  
  In the present invention the fibers of the staple are arranged substantially parallel, either by brush transport against a suitable surface or, in the case of slivers and rovings, by the conventional carding operation. The same substantially untwisted result is obtained. It should be noted that even the most perfect carding does not necessarily achieve absolute parallelism of every fiber and here and there a fiber may be curved around another. Accordingly, the term substantially untwisted&#34; will be used in the practical sense in the claims that there is no substantial or significant twisting to form a yarn. In the specification which follows, however, for brevity and simplicity the shorter term untwisted will be used, but it should be understood that this is used in the same sense. Stitch formation and knitting of the untwisted material of the present invention causes the material to be looped in stitch formation, and this sometimes causes a very slight twisting effect of certain individual fibers. The stitch formation and the interlocking of loops in the knitting locks the material in the fabric and increases the strength and stability thereof, just as is the case with certain very lightly twisted yarns or with yarns which have been texturized by partial untwisting. This is a phenomenon of knit fabrics which is not present or at least not present to quite the same degree in woven fabrics, and the present invention is therefore strictly limited to methods and apparatus for forming knit fabrics or to forming spun yarns.  
  it is a very real advantage of the present invention that it can be used with any knitting machine in which needles form stitches sequentially. As the present invention is applicable to any of these numerous well known and conventional knitting machines, it may. from a somewhat different viewpoint, be considered an attachment, and this makes it possible to incorpo rate the present invention into existing knitting machines without rebuilding. All that is required is suitable attachment of the supply elements of the present invention to the machine at the proper points. Where the present invention is used as an attachment, it can easily be made removable so that the same knitting machine may be used during one period for producing the fabrics of the present invention and at another period changed over to knit conventional yarns, such as twisted, continuous filament. and the like. When a new machine is being constructed, it is. of course, possible to build in the elements feeding or supplying the untwisted material as an integral part of the machine. and from an apparatus standpoint such machines are included in the present invention. However, even when a new machine is being built there is often considerable advantage in making the material supply mechanism removable, and such a modification may be considered preferred.  
  It is a further advantage of the present invention that the overlapping hairpin loops of the untwisted material are usually sufficiently strong even before knitting to permit operation of the machine at normal high speeds. However. this will vary with the nature of the untwisted material used and in some cases small reductions in knitting speed may be found desirable. Ordinarily if any reduction in speed is thought necessary, this is comparatively small and does not represent a serious additional cost offsetting the saving by elimination of the twisted yarn forming step for part or all ofthe yarn supplied.  
  Since the knitting machines themselves are not changed by the present invention. in further sections of this specification describing drawings and preferred embodiments the machines will be shown semidia grammatically, illustrating only sufficient of the machine to show where the invention is attached. Also, only one type of knitting machine will be described, namely a circular knitting machine in which the needles are stationary. The elements of the invention are not changed in the other types of machines, and this is an advantage as the feeding mechanism of the present invention is applicable to a number of different types of knitting machines.  
  ln the above description reference has generally been made in connection with machines which knit single knit fabrics. The invention, however, is not limited thereto as the feed mechanism may feed both to a knitting line or head and to the dial of a double knit machine, which makes the present invention applicable to the important field of double knit fabrics, which are finding increasing use. It should be noted that in a double knit fabric it is not at all necessary that the main knitting head and the dial be fed with the same staple fibers. On the contrary, different fibers may be used so that the two faces of the double knit fabric are not the same, and it is also possible to knit one of the faces with a different type of material. for example with a twisted yarn, texturized or untexturized, or with continuous filament yarns. This is another illustration of the general applicability of the fiber feed of the present invention to the production of a number of different designs of knitted fabric.  
  As has been stated, the present invention can feed either staple or carded material, such as slivers or rovings. When staple is fed, a feed box and feed rolls as well as a brush and plate are required to align the random fibers and to apply them to the hooks on the disc or drum or other shape of conveying element. From one point of view this might be considered as producing a result similar or analogous to carding but without the additional cost of this operation. When carded material, such as slivers or rovings, are used, of course the brush and plate are used to align the fibers and the sliver is fed direct to the hooked disc or wheel without the feed box and feed rolls. The question of whether to choose one material or another involves in one respect a question of economics. Other things being equal, feeding staple, which eliminates the cost of carding and formation of slivers or rovings, makes this alternative somewhat more economical. On the other hand. slivers or rovings can be wound into packages and are more easily transported over considerable distances than loose staple. so for certain uses where a sliver is produced a considerable distance from the plant actually knitting the fabric, the small additional cost of producing sliver or roving may be more than offset. It is an advantage of the present invention that, as far as material fed is concerned, the best economic compromise can be chosen. It should, of course, be noted that where fabrics of more than one face are produced, for example double knits, the supply material need not be the same to the elements knitting the two faces and can be staple for one face and sliver for another face. This adds an additional versatility to the invention.  
  In addition to the very marked cost saving when knitting the hairpin-shaped material alone, because of elimination of the expensive operation of yarn formation and/or texturization, the invention presents a further advantage. One of the problems associated with knitting ordinary spun yarn on a machine, and particularly a circular machine, is yarn rupture at castoff. The needles are often carried a little lower in the machine slot, such as cylinder slot, to guarantee complete knockover. However, this imparts a strain to the yarn, which has to bend over the adjacent slot and under the adjacent needle head. As a twisted yarn often has little elongation, breaking of the yarn or at least partial rupture may be a problem with some yarns. With the same fiber material the present invention reduces the likelihood of breakage or ruptures because the fibers in the loops are substantially untwisted and so are more free to move and compensate for the increased tension during knockover. This freedom of fiber movement may be taken advantage of in one or more ways. With the same bulk of material, the operation is rendered less subject to interruption or higher knitting speeds may be used or both. Another advantage is that with the freedom of fiber movement in the present invention a greater amount of material can be entered in the needle path, which often makes a better product. These advantages are obtained inherently in the process of the present invention and do not require any additional operations or costs.  
  The great advantage of lower cost permits an invasion of a market which is not at present open to many knitted fabrics. This is the market for woven sheeting. A knitted sheet has improved comfort and fitting properties as compared with a woven sheet. but with twisted spun yarn the cost is greatly increased due to the fine yarn size needed and often is prohibitive. so this market is at present largely dominated by woven products. It is true that when knitting with continuous filament the costs may not be as excessive, but the knitted sheeting is too slippery and if texturized, the high cost of texturizing may offset the savings due to higher productivity of a knitting machine. In spite of the potential, improved comfort and fitting properties of knitted sheeting, a large part of this field is still dominated by woven fabrics. The present invention permits knitting sheeting without the prohibitive cost of spun yarn of the very fine size needed.  
 BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation showing the present invention applied to a circular knitting machine of the stationary needle type;  
 FIG. 2 is a diagrammatic showing of the drive;  
  FIG. 3 is an enlarged diagrammatic illustration ofa wheel with carrier hooks and shoe for smoothing out and forming the hairpin-shaped loops;  
  FIG. 4 is an enlarged illustration of the transfer at right angles to FIG. 3;  
  FIG. 5 is an enlarged pictorial of a plain jersey knit fabric using the yarn reinforced modification of the present invention. and  
 FIG. 6 is a diagrammatic showing of forming spun varn.  
 DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows elevation ofa standard circular knitting machine with stationary needles. The machine. which is essentially unchanged by the present invention, has a framework 30, a stationary row of needles l6 and a rotating feed 17 driven from the conventional knitting machine drive. (not shown). The circular knit fabric is shown at 26 and removed by pull rolls 27 to a conventional takeup roll which. as it is not changed by the present invention. is not shown. The rotating feed 17 carries a needle actuating cam 31 which raises each needle sequentially. as can be seen in FIG. 3. A staple supply container 32 is provided with a conveyor belt 1 continuously driven. This carries staple fiber up and discharges into a staple hopper 2, the excess 4 of overflowing staple moving down an inclined apron 3 back into the staple supply at 32. The rate at which the conveyor 1 moves up staple is greater than the consumption of staple in the knitting operation. which will be described below. so that the vertical hopper 2 is maintained continuously full.  
  Staple moves out of the bottom of the hopper and is carried by two inclined conveyor belts through condensing or compacting rolls 6 to a drive feed roll 7 with a backup plate 8. A round brush 9, which can be seen through a portion of the casing which is broken away in FIG. 1, brushes fibers over the backup plate 8 and deposits them on hooks ll ofa hook wheel 12. The details are best seen in FIG. 3. The operation of the brush is in effect a miniature carding and the fibers are brushed onto the hooks 11 in substantially aligned and untwisted form. As the wheel 12 rotates. the fibers brushed onto the hooks are forced by a curved backup shoe 14 which moves the fibers somewhat sideways at a tangent to the books. This results in forming a series of overlapping hairpin-shaped loops 15.  
  FIG. 2 shows a diagrammatic drive of brushes and wheels shown in FIG. 1. The drive is by a shaft 35 provided with a sprocket 36 meshing with a chain 18, which performs the function of a gear at lower cost.  
  As the wheel continues to move. it reaches a portion adjacent the row of needles 16. There are provided needle spaces 13 through which the needles 16 move up and down by the action of the cam 31 as the rotary feed 17 moves. This can be clearly seen on FIG. 3, which. as far as needle actuation is concerned, is semidiagrammatic because this portion of the machine is not changed by the present invention. Since the loops have been moved slightly sideways, they encounter the hooks at an angle. and as the needles move down they draw the loops of fibers 15 off the hooks 11. Because of the overlapping of the loops this behaves essentially as a continuous untwisted yarn supported. of course. by the hooks 11 until the needles engage the loops.  
  The operation of the circular knitting machine is conventional and the needles form stitches at a fabric line 33 in the conventional manner. Since the stitches of the knit fabric lock the overlapping loops. they do not pull out once they have been knitted. The machine shown in FIGS. 1 to 4 is programmed to knit a standard simple jersey fabric. as can be seen in FIG. 5 which shows a fabric. with the stitches grossly exaggerated for clarity. It will be seen that in the fabric the overlapping loops l5 become a continuous locked yarn. The simple jersey stitch lends itself readily to pictorial illustration in FIG. 5, but of course any other pattern of stitch may be used by suitable programming of the circular knitting machine in the conventional manner. This programming is not changed by the present invention. which in one respect may be considered to have ended when the needles l6 hook onto the loops and draw them off from the hooks 11 on the wheel 12. Stitch formation is not changed by the present invention though of course the characteristic appearance and feel of the resulting fabric is influenced by the fact that it is formed at least in part by substantially untwisted fibers. Since the actual stitch formation is not changed by the present invention. the details of the needles are not shown in FIG. 3 and would not appear in any event because FIG. 3 is looking at the needles edge on. Of course the needles are provided with the conventional latches or beards as in any circular knitting machine. Such additional details. which would not appear in FIG. 3, are shown. in part. on FIG. 4, which because of its orientation shows the needles as latched needles. Of course they could be bearded needles with the suitable auxiliary apparatus. such as pressers. As has been stated. the particular design of needle. as such. forms no part of the present invention.  
  As has been stated above. it is sometimes desirable to provide a monofilament. or tightly spun ladder yarn, or reinforcing yarn. In FIG. 1 this is shown as two ply from two packages 25, which lead to the point at which the needles grasp the overlapping loops l5 and is knit with the overlapping loops. The two plies of ladder yarn 34 are shown in dashed lines in FIG. 1; but as they are buried in the untwisted loops 15, in FIG. 5 they are shown in phantom in one course. The showing is in one course only in order not to confuse the drawing in FIG. 5. If the overlapping loops of untwisted fibers of the present invention were not present, the ladder yarn of course would knit but would produce a fabric of entirely different characteristics. This will be clear from a moment&#39;s consideration of FIG. 5.  
  In FIG. I there has been shown in dashed lines an alternative feed from a supply of slivers 28. the slivers themselves being shown at 29 and being fed onto the hooks II, as has been described above. The operation of the machine, of course, is the same whether sliver or staple is used, staple bin, aprons. etc., of course being dispensed with when operating with sliver. However, the sliver supply must rotate to keep it in alignment with hooked wheel. The cost of drafting slivers or rovings is very much less than that of producing twisted yarn, but even this small cost is offset to a considerable extent by the elimination of brushes and other elements which are necessary with staple. As has been mentioned above. the use of carded material. such as sliver, or uncarded staple as raw material is a matter of choice dictated by the conditions of supply and the fabric desired.  
  The drawings show a circular knitting machine with stationary needles and moving or rotating feed. The other type of circular knitting machine with moving needles and stationary cam may, of course. also be used with the feed of the present invention, which of course in that case is also stationary. When flat knit fabrics are knit. only stationary needle machines are available and the cam actuation and feed are moved back and forth instead of around as for flat fabrics only this type of machine with stationary needles is practical.  
  FIG. 6 is a diagrammatic illustration of spinning yarn with the hairpin loops of the present invention. As has been stated above, the spinning may be with hairpinshaped loops only or with a ladder or reinforcing yarn of twisted or continuous filament character. In order to illustrate both modifications. FIG. 6 shows the ladder yarn 25 passing over a guide roller 37 and joining the hairpin-shaped loops. the two feeds then passing through a pair of drive rolls 38. From here the two materials are introduced into an air twister or spinner 39 of the modified form described in the Pike applications above referred to. Since the spinning loop air spinner 39 is not changed. except by the fact that it receives a different material including hairpin loops, it is shown purely diagrammatically. and the tangential air blast introducing means are. therefore. not shown as they are the same as in the Pike air spinner.  
  As FIG. 6 is purely diagrammatic, the mechanism for producing the hairpin-shaped loop is not repeated as it is the same illustrated in FIGS. 1. 2 and 3. Even though FIG. 6 is a diagrammatic showing. for clarity parts which show carry the reference numerals which have been used in the full description of this part of the apparatus in the preceding figures.  
  After passing through the air spinner 39, the now spun yarn passes through a second pair of rolls 40 and is wound up in a conventional package. as shown at 41. As has been mentioned above. the effect of spinning increases the cross-section of the yarn produced and requires, therefore. an overfeed to the air spinner. In other words. the rolls 38 must turn at a higher rate than the rolls 40 to provide for the necessary overfeed. The need for overfeed is just as great when hairpin-shaped loops are spun without a reinforcing or ladder yarn.  
 but. of course. the amount of overfeed must be adjusted for the particular material being spun.  
  The spinning loop air spinner or twister 39 is not by itself a new element and is not claimed in this applica tion except as part of a combination including the formation of the overlapping hairpin-shaped loops, which is the major feature of the present invention. The air spinner is not a new element and when used as a spinner with other material or as a texturizer the same requirements for overfeed are present. Accordingly, since the element is an old element, details of the drives to the rolls 38 and 40 are not shown as they do not form. as such, any part of the present invention.  
  In the reinforced yarn illustrated in FIG. 6, the ladder yarn 25 is buried in the soft hairpin loops as a result of the air spinning. These, however, are twisted because the fibers are separated as they enter the air spinner. As has been mentioned above, spinning is from the inside out instead of from the outside in, as is the case with many mechanical spinners. Because of the great compactness of the air spinner, this is preferred and hence is illustrated in FIG. 6.  
  It should be noted that the yarn from the package 41 can be used in fabric making, for example by knitting. If there is a ladder yarn 25 combined with the hairpinshaped loops and this is knit, the final fabric is smooth on both sides. If there is no ladder yarn and yarn spun only of the hairpin-shaped loops, when a single knit fabric is produced a softer surface results but not such a soft and fuzzy surface as results when the hairpinshaped loops are not spun into yarn as is described in connection with FIGS. 1 to 5. For many fabrics such a fuzzy surface is desired, but where it is not desired there may be knitting with a ladder yarn, which is an alternative shown in FIG. 3, the ladder yarn being numbered 25 as in FIG. 6. It is, of course, possible in double knit fabric to have different feeds for the different sides, which gives further possibilities in changing the fabric design and adds to the versatility of the invention.  
 I claim:  
  1. In a process of producing a knit fabric by knitting substantially untwisted, linear material the fibers of which are substantially parallel oriented, the improvement which comprises forming the substantially untwisted and substantially parallel fibers of the linear material into overlapping hairpin-shaped loops, conveying said loops and feeding them to the needles of a knitting machine, the feeding of the overlapping hairpins to the needles substantially transverse to the front of the needles.  
  2. A process according to claim 1 in which the feed moves and the needles are stationary.  
  3. A process according to claim 2 in which the fabric is circularly knit.  
  4. A process according to claim 1 in which the substantially untwisted material is drafted untwisted fibers of the sliver or roving type.  
  5. A process according to claim 1 comprising feeding at least one ladder yarn selected from the group consisting of pretwisted yarns and continuous filament yarns to the knitting needles associated with the untwisted linear material.  
  6. A process according to claim 1 in which the substantially untwisted linear material is formed by conveying fibers from a staple supply into a vertical hopper. moving said fibers through condensing means. transporting said fibers from said condensing means by a doffer to a given point, picking up the fibers as overlapping hairpin-shaped loops from the doffer with a hooked wheel at right angles to the direction of rotation of said doffer, and conveying the overlapping loops to the needles of the knitting machine.