METHOD AND DEVICE FOR MANUFACTURING STITCH BONDED TEXTILES

Abstract: Method for sewing knitting threads into a web submitted to a warp knitting machine, in which a sharp-nosed row of knitting needles (65, 66) penetrates the web for sewing the knitting threads into the web along a row of stitches with each knitting cycle. With each knitting cycle two rows of knitting needles simultaneously penetrate and withdraw from the web such that a zig-zag-shaped penetration pattern with two penetration rows extending parallel to the needle array is produced with each knitting cycle.

Description: METHOD AND DEVICE FOR MANUFACTURING STITCH BONDED TEXTILES Conventional stitch bonded textile fabrics are well known in the art. They are produced by bonding together the fibers of a fleece by means of a plurality of columns of stitches. If envisioned in terms of conventional woven textiles with warp threads and weft threads, the plurality of stitch columns constitute the warp yarns and the bundle of fibers encompassed within an individual stitch and adjacent stitches in the weft direction constitute the weft yarns. The advantage of such a fabric is that it is composed almost entirely of weft-wise oriented staple fibers laid down in a fleece, which are much less expensive than spun or filament yarns or thread. The only yarns present are those in the columns of stitches. Stitch bonded fabric can also be produced more rapidly than by weaving or knitting. There are several disadvantages of stitch bonded fabrics that limit its use and which virtually exclude it from use in apparel except, on occasion,, as a liner material for suit coats and the like. One such disadvantage is a low weft-wise strength or stability, which is attributable to a relatively poor binding power between the stitch loops and the weft-wise bundles of fibers that run through such loops. When the fabric is subjected to a weft-wise tension, the fiber bundles tend to slip through the loops, with a resultant distortion of the fabric. Another disadvantage is a low restistance to pilling, again at¬ tributable to the poor binding power between stitch loops and fibers in the weft-wise bundles. Individual fibers pull out of the bundle and pill on the surface of the fabric. A further disadvantage is that the fabric has poor draping characteristics. This is the result of the relatively large length of the stitches which, in turn, create relatively large diameter weft- wise bundles of fibers. These coarse bundles are relatively stiff, thereby resisting drape folds parallel to the warp-wise stitches. A machine, also called a sewing-knitting machine, is e.g. described in the DE-OS 25 25 031. This machine is used to reinforce a web consisting of a non-woven fabric by sewing knitting threads into it It is also known from the DE-PS 31 40 480 to lay parallel filler threads over a textile support layer and to reinforce this combined web by sewing knitting threads into it Using the previously known methods and corresponding machines a row of stitches has been sewn into the web parallel to the needle array with each knitting cycle, whereby the distance between individual stitches narrows as the gauge of the needle array becomes finer. As it becomes finer, the penetrations move so closely together that they resemble a tear-off perforation, thus nullifying the reinforcement effect Furthermore there is the problem that, when the gauge becomes very fine, the filler threads are displaced by the knitting needles penetrating the web thus grouping themselbes irregularly in relation to the penetrations. Apart from an exessively irregular appearance of the fabric, this may lead to a bunching of filler threads with the filler threads themselves being penetrated and thus damaged in the process. The bunching of filler threads or fibers of a support layer (non-woven fabric) also leads to the knitting needles becoming bent. The present invention provides a novel stitch bonded fabric and a machine and process for producing the same. A conventional machine for producing stitch bonded fabric consists of a supply package of input fleece, feed belts that convey this fleece to an assembly including fleece pins or web holders, sinkers, a reciprocating needle bar with a plurality of needles aligned along said bar in a single plane, corresponding yarn guides on the other side of the web to lay the stitching yarn in the needle hooks, and a take-up means for the finished fabric. The just described elements are the main components of the stitch-bonding machine - numerous other ancillary components also exist in the machine. In operation, the input fleece is selectively advanced past the needles as they repeatedly pierce the fleece. Each needle - and its corresponding yarn guide - creates a stitch column in the fleece in a warp-wise direction. Since all of the needles are in a single plane, each column of stitches has loops that are in weft-wise alignment with corresponding loops in adjacent columns. The aligned loops in a given weft- wise row capture a bundle of fibers such that the bundle is straight across the fabric in a weft-wise direction. In the present invention the plurality of needles in the needle bar are not all in one plane, but instead are offset or staggered. Needles in the first, third, fifth, seventh, etc. position are in a first plane and needles in the second, fourth, sixth, eighth, etc. position are in a second ' plane. When the offset needles pierce the fleece and knit the warp-wise columns of stitches, the loops in adjacent columns are similarly offset from each other such that the weft- wise fiber bundles captured within the loops are distorted in an oscillated fashion - forming a pattern somewhat similar ^o two sinusoidal curves 180° out of phase with each othe * r - rather than a straight bundle as is present in a conventional stitch-bonded fabric. These twisted or distorted fiber bundles have a much improved binding power with the loops in the column of stitches, which greatly improves the weft- wise strength or stability of the fabric. The improved binding power is attributable to the wrap angles of the weft-wise fiber bundles relative to the individual stitch-loops in the warp-wise columns. This improved binding power results in a fabric with a greater pilling resistance as well as a high weft stability. Additionally, the fabric drape is improved across the filling by the oscillating effect of the fiber bundles. The appearance of the fabric is also notable. The fiber bundles, due to the wrap angles, have a degree of alignment both toward the warp-like chains and the filling fiber creating a diagonal pattern having the appearance of a woven twill. A further advantage of an offset needle 'configuration is that a finer guage fabric can be produced. With conventional single plane needle configurations the dimensional relationships between needles, fleece pins, sinkers and yarn guides limit the machines to 28 guage. When sufficient needle offset is achieved so that the guide bar blades can fit between the needles, two guide bars may be used to create a single bar construction with a fineness as high as 56 guage. A si.ngle sinker and a single fleece pin can serve two needles offset- from each other by configuring the sinker and the fleece pin .as a crank, in a manner to be more fully described below. This finer guage fabric is characterized by superior strength, drape and appearance. It also enables the use of shorter fibers in the fleece. The invention is further based on the requirement to reduce the separating effect which the penetrations have upon the web in terms of the above-mentioned tear-off perforation and the bunching effect, whilst maintaining a dense penetration pattern. According to the invention this is achieved by the characterising features of claim 1. Due to the zig-zag-shaped needle penetration pattern produced with each knitting cycle and repeated with each subsequent knitting cycle, it becomes possible to select a greater needle distance for each row of penetrations and to compensate for this by arranging for a subsequent row of penetrations to be laterally offset from the former resulting in the zig-zag-shaped needle penetration pattern such that in projection vertically to the needle array a high density of needle penetrations is obtained with correspondingly high reinforcement without the above-mentioned disadvantages. Perferably the web take-off is set in such a way that its length per knitting cycle is essentially equal to twice the distance of the penetration rows produced by both knitting needle rows. In this case consecutive zig-zag-shaped needle penetration patterns of equal distance are obtained, which imparts a uniform appearance and a correspondingly uniform reinforcement to the web. The web may e.g. be a non-woven fabric. It is also possible to supply a web formed of diagonal filler threads. Moreover such filler threads may be combined with any given support layer, in particular to form a non-woven fabric. A warp knitting machine for performing the above-described method is conveniently constructed in such a way that its two knitting needle rows are arranged on a common guide bar, in which case only one drive mechanism is required for operating both knitting needle rows. In other respects a normal warp knitting machine may be used equipped with sharp-nosed knitting needles as normally used for sewing knitting threads into a web. The invention is more completely described below in relation to preferred embodiments and understanding is facilitated by reference to the drawings herein below. Figure 1 is a schematic view of the major components of a stitch bonding machine. Figure 2 is an enlarged schematic view of the stitching zone of a conventional stitch bonding machine. Figure 3 is an oblique view of the needle bar of the present invention. Figure 4 is an enlarged schematic similar to Fig. 2 but with the needle bar of the present invention employed in the stitching zone. Figure 5 is an enlarged view of the structure of a conventional stitch bonded fabric. Figure 6 is an enlarged view of the structure of a stitch bonded fabric according to the present invention. Figure 6a is a still further enlarged view of portions of three stitch columns and three fiber bundles from the fabric of Fig. 6. Figure 7 is another enlarged view of a stitch bonded fabric according to the present invention, illustrating the twill-like surface appearance of the fabric. Figure 8 is a view similar to Fig. 4 showing modifications to achieve a finer guage fabric. Figure 9 is a cross sectional view of the cooperation between offset needles and crank-shaped sinkers. Figure 10 is a cross sectional view of the cooperation between onset needles and crank-shaped fleece pins. Figure 11 shows a section of the web with a zig-zag- shaped penetration pattern. Figure 12 shows a principal illustration of a side view of the knitting tools of a warp knitting machine, where the web submitted is a non-woven fabric. Figure ^ 13 is an illustration corresponding to figure 12 with a web formed of diagonal filler threads. SUBSTITUTE SHEE' Figure 1 is a schematic of the major components of a stitch bonding textile machine. A roll 10 of fleece - such as produced by a cross folder - serves as an input supply of the fiber fleece which are to be bonded together to produce the fabric. Alternatively, the input fleece can be fed directly from a cross-folder. Feed belts 20A and 20B convey the fleece to the stitching zone 30, where it passes between fleece pins or web holder pins 50 and sinkers 40 in a conventional manner. Needles 60 stitch through the fleece, creating a plurality of warp-like columns of stitches from yarn supplied from packages 80 through yarn guides 70. Closing wire 90 functions in a conventional manner to close the hook on needle 60. Additional guide rolls 20C convey the stitch bonded fabric to take-up package 100. The apparatus in the stitching zone is shown in greater detail in Figure 2. Needle bar 64A holds a plurality of needles 60 (only the closest of which is visible in the figure), each of which has a point 61, a hook 62 and a groove 63 to accommodate closing wire 90. A web path W exists between knocking-over sinkers 40 and web holder pins 50, both of which are attached to the machine by means of sinker leads 41 and web holder pin leads 51, respectively. The point 61 of needle 60 passes through the web, picks up a stitching yarn in hook 62 from yarn guide 70, and pulls the yarn through the web to form, in cooperation with sinker 40, a stitch. ' In a conventional stitch bonding textile machine, there are a plurality of needles 60, all located in the same plane. In like manner, there are a corresponding plurality of sinkers and fleece pins. One embodiment of needle bar 64B of the present invention is shown in an oblique view in Figure 3. Needles 60 are staggered or offset from each other both vertically and horizontally such that they fall into two planes A-A and B-B and such that a needle in plane A lies over the space between two needles in plane B. The horizontal spacing between needles may be varied, as may be the vertical spacing. For example, the offset needles illustrated in Fig. 4 show less of a vertical spacing than the needles in Fig. 3. Thus, when viewed from the side, the embodiment of Fig. 4 has the front needle obscuring a portion of the needle behind it, and so on for all the needles in the bar. While this preferred embodiment is described with respect to offset needles in only two planes, it should be understood that offset needles in more than two planes are also contemplated for some applications. Figure 4 illustrates the stitching zone in a view similar to Figure 2, but in which needle bar 64B of the present invention and its offset needles replace the conventional single plane needle bar 64A of Figure 2. When viewed in conjunction with Figure 3, needle 66 is in plane A-A and needle 65 is in plane B-B, although these planes are vertically closer to each other than those shown in Fig 3. Again, a plurality of needles exists in each plane - only one in each plane is shown . in Figure 4. A conventional stitch bonded fabric is illustrated in Figure 5. A plurality of stitch columns C χ C 2 , C 3 , C 4 , C^ . . . C-_2 are formed in the warp-wise direction, and a plurality of fiber bundles B^ r B 2 , B 3 , B 4 , B 5 —B 12 are formed in the weft-wise direction. As mentioned above, when envisioned in terms of conventional woven fabrics, the columns of stitches C constitute the warp yarns and the fiber bundles B constitute the weft yarns. The vast majority of the fibers in the fleece are captured by the individual stitches and form part of a given bundle but, as is apparent in Figure 5, a small number of fibers f_ lie outside the bundles. When the fabric of Figure 5 is subjected to a weft-wise tension, the fiber bundles have a poor binding power with their corresponding stitches, and slip through same with relative ease. This results in a fabric with a poor, or low, weft stability. A fabric produced according to the present , • invention is shown in Figure 6. The columns of stitches are indicated by reference letters C'^, C' 2 , C' 3 , C' 4 ... -• ' i2 ' w ^ th columns C' lf C' 3 , C' 5 ... knit by needles in one plane and columns C' 2 , C' 4 , C' 6 ... knit by needles in a second plane. Fiber bundles B 1 ^, B' 2 , B' 3 ...B' 12 form a oscillating pattern quite different from the pattern formed by the bundles in Figure 5. Figure 6A is a greatly magnified view of the upper left corner of the fabric structure shown in Figure 6. Three stitch columns '^, C' 2 , C' 3 and three fiber bundles B 1 -,, B' 2 r B' 3 are shown in Figure 6A. The oscillating path assumed by each bundle is readily apparent from Figure 6A. Bundle B' j _ is completely encompassed in stitch S^ a of column C'^ but then, moving to the right of the figure (in a weft-wise direction)-, splits so that roughly half of bundle B'ι is encompassed in stitch S 2a of column C' 2 and the other half is encompassed in stitch S 2 ^ of column C'2» Continuing to the right of the figure, bundle B' comes together and is completely encompassed within stitch S 3a i column C' 3 - The bundle configuration just described occurs with the majority of the fibers in a given bundle. In actual application, there exists some minor but unpredictable fiber cross-over from bundle to bundle, such as shown by filament f_ passing from bundle B' 2 to B 1 ^ and beyond. This oscillating pattern repeats itself throughout the fabric and creates a more efficient binding power attributable to greater frictional engagement between bundle and stitch created by the wrap angle of the bundle around the stitch yarn. This creates a greatly _ improved weft-wise tensile strength and resistance to distortion, or a high weft stability. This fabric structure also results in good pilling resistance and improved drape characteristics across the filling. With particular reference to Fig. 7, it can be seen that the just described oscillating pattern formed by the yarn bundles creates a diagonal, twill-like surface pattern on the fabric. The actual bundles are visible in the upper left corner of Fig. 7 - the twill¬ like diagonal pattern is schematically illustrated in the remainder of Fig. 7. Comparative tensile strength tests were run on a sample of conventional stitch bonded fabric and a sample of fabric produced according to the present invention. In the conventional fabric, the distance between stitches in a given column was 1.4 mm. In the sample according to the invention, the needle planes A-A and B-B were offset 0.7 mm and the distance between stitches in a given columns was held to 1.4 mm. Thus, the stitches in adjacent columns were offset from' each other by half their length. The guage of the two samples was fehe same, i.e., 28 gauge. The fleece consisted of 4 denier - four inch length polyester. The weight of one sample of the conventional fabric was 4.67 ounces per square yard while the fabric of the invention weighed 4.40 ounces per square yard. Five - test samples measuring four inches by six inches were taken from both the conventional fabric and the fabric made according to this invention. In the tables below, the test results are set forth. The test employed a conventional- Scott Tensile Tester, with tension applied until the sample failed. Conventional Fabric Tensile- Tensile Initial Modulus Warp Weft Modulus Filling Direction Direction Filling g lbs. (Filling) g lbs. Sample 1 81 83 252 1083 Sample 2 80 91 252 1083 Sample 3 80 92 252 1083 Sample 4 77 94 270 1305 Sample 5 79 87 260 1083 Average 79 89 257 1127 Fabric According; to Present Invention Tensile- Tensile Initial Modulus Warp Weft Modulus Filling 'Direction Direction Filling gm lbs. (Filling) gm lbs. Sample 1 83 105 710 1630 Sample 2 83 92 1054 1640 Sample 3 73 127 1054 1833 Sample 4 73 90 695 1830 Sample 5 78 94 1054 1640 Average 78 102 913 1715 % Difference -1% 15% 255 52 The table headings are defined as follows: Tensile-Warp Direction - lbs: A tensile force measured in pounds was applied in the warp direction until failure. Tensile - Weft Direction (Filling) - lbs: A tensile force measured in pounds was applied in the weft direction until failure. Initial Modulus Filling - gms.: An indication of force per unit stress, i.e., stress in grams divided by strain - i.e. % stretch. . Thus, for example. Sample 1 of the conventional fabric indicates that for 252 grams of force applied, the sample stretched 1%. This is an indication of the resistance to distortion. Modulus Filling - grams: i.e., the additional grams of force required to take the sample from its initial modulus to failure. This is an indication of the resistance to failure after the fabric has been distorted. The samples were also subjected to a standard ASTM Random Tumble Pilling Test, and compared with samples - in a visual grading scale of 1-5, with 5 being excellent. The conventional fabric was 3.0 - i.e. moderate pilling. The fabric of the invention was 4.5 - very slight pilling. As is apparent from the above reported tests, there was an average 15% improvement in the weft-wise strength of the fabric, and the initial modulus indicates a dramatic 255% improvement in the fabric's ability to resist weft-wise distortion. Also, the ability of ' the inventive fabric to resist pilling was markedly improved over the conventional fabric. I have also determined that offsetting the needles in a stitch-bonded textile machine permits the production of a finer guage stitch-bonded fabric. It is necessary carefully to control dimensions of the various components in the stitching zone. Figure 8 is a schematic view of the components in the stitching zone when modified to produce a fine guage fabric * . Like elements are numbered as in Fig. 4, but with prime (') designations. r In this embodiment, the plane of needles which includes needle 66' is vertically offset from the plane of needles which includes needle 65' by an amount greater than that shown in either Fig. 4 or Fig. 3. The vertical offset may be, for example, four and one- half stitch lengths -i.e., 6.35-mm which is sufficient to accommodate yarn guide blades that are 2 mm wide. Several of the knitting components, or elements, require modification: (1) the sinker blades 40' must be made longer so that the offset needles can fit between sinker leads 41' and sinker nose 42'; (2) the fleece pins 50' must also be made correspondingly longer; (3) closing wires 90^ and 90' 2 must be offset in two planes corresponding to the needle offset such that they can ride in the corresponding grooves in the needles; and (4) the needles in the upper plane (as seen in Fig. 8) are cranked at location D so that needles in both planes can be cast into a conventional sized needle bar 64B'. Alternatively, if needle bar 64B is made larger in the vertical dimension, the upper needles need not be cranked. The clearance between the yarn guide blade and needle - both in front and behind the hook - should preferably be a minimum of 1 mm. With longer sinker blades, the opening of the sinker window X (see Fig. 9) will be large enough to f β accommodate both needles - in this example, the window would be 8.85 mm. Both the sinker blades and the fleece pins are bent into a crank-like configuration, as is visible in Figs. 9 & 10. This cranked configuration permits a single sinker blade, and a single fleece pin, to serve two needles, one in each plane. Sinker pins 40' should preferably have a hole 43' punched in each with a supporting wire 44' running therethrough to support the back side of the needles 66'. (The lower needles 65' are supported by sinker nose 42' . ) The crank offset of both sinker blades and fleece pins is determined by dividing the guage - i.e., the number of needles per inch into 25.4 mm - the number of millimeters in one inch. Thus for a 56 guage needle assembly, the crank offset is 0.454 mm, indicated by Y in Figs. 9 and 10. A comparison of the relative cost of manufacturing a conventional 4 oz., 28 guage, 70 den. yarn fabric with an equivalent 4 oz., 56 guage, 50 den. yarn fabric indicates that the 56 guage fabric is only about 3 cents/sq. yd. more expensive than the 28 guage fabric, with no loss of efficiency in knitting. The finer guage fabric would have vastly superior strength, drape and appearance, and would enable the use of a shorter staple length fiber in the fleece. Figure 11 shows a section of a web 101 formed of diagonal filler theads 104, which has been treated by the method according to the invention and which was subjected to two knitting cycles during which two needle penetration rows respectively were produced simultaneously, i.e. rows 102a and 102b and 103a and 103b. Within the two rows 102a and 102b a zig-zag-shaped penetration pattern exists of which the penetrations of row 102b are symmetrically offset in relation to the penetrations of row 102a. Rows 102a and 102b are simultaneously worked in one knitting cycle. The same applies to the tow needle penetration rows 103a and 103b. The take-off length of the web per knitting cycle is such that the distance with which penetration row 103a follows penetration row 102b is twice the distance between penetration rows 102a and 102b. In this way the same penetration pattern repeats, at a distance such that the individual penetration patterns repeat symmetrically following each other resulting in an altogether uniform appearance of all penetration patterns. As a consequence a correspondingly evenly distributed reinforced web 101 is obtained on the basis of the needle penetrations and the worked-in knitting threads. But it is also possible, of course, to operate the respective machine at a shorter or longer web take-off per knitting cycle. As illustrated the needle penetrations of row 102b as projected, lie resp. centrally between two penetrations of row 102a in feed direction of web 101 (indicated by the arrow) so that when projected this way, a uniform relatively narrow pitch is obtained. But since this narrow pitch does not belong to a row of adjacent needle penetrations, the penetrations of one knitting cycle resp. being spaced and offset at a distance from each other, sufficient distance remains between individual penetrations of rows 102a and 102b to ensure that undesirable bunching of the fibres of web 101 or diagonal filler threads 104 is avoided, although in total a SUBSTITUTE SHEE1 considerable density of individual needle penetrations is obtained across web 101. In the left half of figure 11 some knitting threads 119 are drawn laid in a fringe. It should be noted, however, that the knitting threads may also be worked into the web in the form of tricot laying. The respective type of laying depends on the requirements which the textile fabric to be produced has to meet. The adjacent penetration rows shown in figure 11, i.e. 102a and 102b and 103a and 103b are, as already mentioned, produced simultaneously in a single knitting cycle, with 2 rows of sharp- nosed knitting needles penetrating the web 101 submitted at any one time. » The knitting ■ tools of the warp knitting machine used in this case are illustrated in figure 12, the base fabric being a web in the form of a non-woven fabric 107. These knitting tools consist of sharp-nosed slide needles 108 and 109, whereby these two needles belong to one row of slide needles resp. extending longitudinally to the needle astray. As the two slide needle rows containing slide needles 108 and 109 therefore penetrate (the web) they produce the penetration rows 102a and 102b seen e.g. in figure 11. The two neefdle rows containing slide needles 108 and 109 are both attached to sliding guide bar 120, i.e. they are operated jointly as the guidfe bar 120 is moved up and down in the customary way. Assigned to -slide needles 108 and 109 are the slides 111 and 112, which are also operated by a common sliding guide bar 113. Cooperation between needles 108 and 109 and slides 111 and 112 is as commonly known for slide needles. Laying of the warp threads serving as knitting threads is effected by two laying guides 124, 125 for each two slide needles 108, 109, the laying guides being suspended in the known manner from ? T < *-' ■ -- laying guide bars 116, 117 and operated by the same. One laying guide would already suffice for each two knitting needles 108 and 109. In order to produce special warp thread layings, however, more than one laying guide may be conveniently provided. With the warp knitting machine illustrated the web submitted in the form of non-woven fabric 107 is supplied via the knock-over sinker 118 and held from above in a downward direction by the trace comb 106. When the guide bar 110 is operated, two penetration rows (e.g. 102a and 102b in figure 11 are produced by the two needle rows containing knitting needle 108 and 109, which two penetration rows are repeated with each subsequent knitting cycle. With the web take-off speed set appropriately, consecutive zig-zag-shaped needle penetration patterns of equal distance are obtained resulting in the altogether uniform appearance seen in figure 11. This figure also reveals that the warp knitting machine of figure 12 is able to operate at twice the take-off speed compared to other machines with only one row of knitting needles and thus with twice the output since one knitting cycle on this machine corresponds to two knitting cycles of a machine with only one row of knitting needles. To produce fringe-laying as revealed in figure 11, the two laying guides 114 and 115 are required, which are assigned respectively to the two knitting needles 108 and 109 for laying the warp threads around the respective knitting needles. The same machine is illustrated in figure 13 but instead of a non- woven fabric 107 a web of diagonal filler threads 104 similar to those illustrated in figure 11 is submitted. It is pointed out that it is , of course, also possible to supply a web which may be a combination of non-woven fabric and diagonal filler thread. Textile webs other than those described may also be submitted provided they can be penetrated by the sharp-nosed needles. In other respects the function of the machine illustrated in figure 13 entirely corresponds to that of figure 12. SUBSTITUTE SHEE "

Claims: Claims 1. Method for sewing knitting threads (119) into a web (101) submitted to a warp knitting machine, whereby a row (108) of sharp-nosed knitting needles penetrate the web (101) thereby sewing the knitting threads (119) into it along a row of stitches with each knitting cycle, characterised in that with each knitting cycle two rows of knitting needles (108, 109) simultaneously penetrate and then withdraw from the web such that a zig-zag-type pattern of two penetration rows (102a, 102b; 103a, 103b) extending parallel to the needle array is created with each knitting cycle. 2. Method according to claim 1, characterised in that the length of web take¬ off per knitting cycle essentially corresponds to twice the distance of the needle penetration rows (102a, 102b; 103a, 103b) created by the two rows of knitting needles. 3. A method of stitch bonding a fleece comprising advancing a fleece to a stitching zone and forming columns of stitches in said fleece that have adjacent weft-wise stitches offset from each other. 4. Method according to claim 1 or 2, characterised in that the web submitted is formed of diagonal filler threads (104). ΓJT . 5« A stitch bonded fabric comprising a fiber/'fleece of columns of warp-wise stitches, said stitches adjacent to each other in a weft-wise direction being offset such that the bundles of fibers captured within said stitches are distorted in an oscillated fashion forming a pattern 10 similar to two sinu-soidal curves 180 degrees out of phase with each other. 15 6. A machine for making stitch bonded fabric including a stitching zone comprising a web path, fleece pins and yarn supply guides on one side of said path, and sinkers and a • plurality of needles on the other side of 0 said path, said plurality of needles being carried by a needle bar and mounted such that alternate needles are aligned in more than one plane. 7. A needle assembly for use in making stitch 5 bonded fabric comprising a plurality of needles being carried by a needle bar and mounted such that alternate needles are aligned in more than one plane. 0 8. The apparatus of Claim 6 or 7 wherein the displacement between said planes is less than the width of a needle. S 9- The apparatus of Claim 6 or 7 wherein the displacement between said planes is more than the width of a needle. 0 1°« The apparatus of Claim 6 wherein said fleece pins and said sinkers are formed in a crank-like pattern such that each given fleece pin and sinker blade can serve two off-βet needles.

Inventors: WILDEMAN MARTIN, WUNNER ROLAND, WILDEMAN, MARTIN, WUNNER, ROLAND
Applicants: LIBA MASCHF, WILDEMAN MARTIN, LIBA MASCHINENFABRIK GMBH, WILDEMAN, MARTIN
Application year: 1990
Main classification: D04B21
IPC codes: D04B21, D04B23