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(11) | EP 0 261 800 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Knitting process |
| (57) A double-faced knitted structure having on one or both faces a plurality of irregular
puckers is produced by knitting on a knitting machine having a pair of opposed needle
beds. At least two ends of non-contractible yarns are knitted on said needle beds
to produce at least two knitted courses and at least one end of a contractible yarn
is laid-in between the faces of said double-faced knitted structure and is intermittently
attached to the knitted structure along the length of said two courses. |
[0001] The present invention relates to a novel process of knitting employing a twin bed knitting machine, which enables a variety of new and interesting surface effects to be produced even from simple knitting patterns.
[0002] The present invention consists in a process for producing a double-faced knitted structure having on one or both faces, preferably on each face, a plurality of irregular puckers by knitting on a knitting machine having a pair of opposed needle beds, characterized in that at least two ends of non-contractible yarns are knitted on said needle beds to produce at least two knitted courses and at least one end of a contractible yarn is laid-in between the faces of said double-faced knitted structure and is intermittently attached to the knitted structure along the length of said two courses.
[0003] The terms "non-contractible" and "contractible" as applied herein to a yarn refer to the state of that yarn only in the course of the knitting process.
[0004] The contractible yarn can be an elastic yarn or a shrinkable yarn. Where the yarn is elastic, it must be held under tension during knitting in order that, after knitting, its natural elasticity will cause it to contract. Where the contractible yarn is a shrinkable yarn, it should be subjected to the necessary treatment to cause it to shrink, for example by subjecting it to high temperatures (e.g. by immersion in very hot water) or by chemical treatment. Since the contractible yarn is not attached to the fabric for a substantial part of its length, it contracts and bunches the fabric together; between the points of the fabric where the contractible yarn is attached, irregular puckers are formed. By appropriate arrangement of the points of attachment of the contractible yarn, a variety of patterns may, if desired, be formed from these puckers. It should be noted that, where the contractible yarn is attached to one or both faces of the fabric, it cannot contract and puckers are not formed. This provides an additional patterning possibility in addition to the well-known means of patterning by alternating colours from one needle bed, and hence from one face, to another.
[0005] In a preferred embodiment of the invention, knitting of non-contractible yarns takes place on all or substantially all (e.g. at least 80% and preferably at least 90%) of the operating needles of each needle bed. However, it is not necessary that the whole of each non-contractible yarn should be knitted in and, as is well-known, short floats (e.g. of 5 or less, preferably 3 or less and more preferably 2 or less, needles) of the non-contractible yarn(s) may be permissible.
[0006] On the contrary, the contractible yarn is merely laid in for the majority of its length, apart from intermittent points of attachment, either by a knitted stitch or by a tuck stitch or merely by being held at points of attachment between the two layers of fabric, as explained below. Preferably, only from 1% to 50% of the needles of one needle bed engage the contractible yarn, more preferably from 5% to 30% and most preferably from 20 to 25%. The precise arrangement of these points of attachment and whether they are formed by knitted stitches, tuck stitches or otherwise will be determined by the intended pattern.
[0007] At least one face of the fabric is knitted from a non-contractible yarn, and preferably both faces are so knitted. However, if one face of the fabric is knitted wholly from a contractible yarn, then this face will contract, without puckering, thereby producing a fabric having one face formed of irregular puckers (the face knitted from the non-contractible yarn) and one face free from such puckers.
[0008] The invention can be employed with any knitting machine, preferably weft knitting machine, having a pair of opposed needle beds. For example, it may be employed on the well-known flat bed machines, for example the purl or V-bed machines, or circular machines, e.g. of the dial and cylinder type or circular purl machines, especially the double Jersey machines. If desired, the machines can be equipped with a presser foot to achieve greater control of the knitting and to achieve special patterning effects by means well-known in the art (see, for example, "Knitting Technology" by D.J. Spencer, Pergamon Press, 1986, especially at pages 212-214). However, the precise nature of the knitting machine employed is not critical to the invention, provided that it has a pair of opposed needle beds capable of producing a double-faced fabric.
[0010] A very wide range of yarns can be employed in the present invention. Indeed, virtually any yarn may be employed as the non-contractible yarn, be it synthetic or natural. The nature of the non-contractible yarn, of course, will have a very significant effect on the appearance, feel and weight of the final fabric, since it is essentially only the non-contractible yarn that will appear on the face of the fabric, the contractible yarn being trapped between the two layers of fabric. Hence, the non-contractible yarn or yarns will be chosen having regard to the desired appearance and feel of the fabric. If an elastic yarn is fed to the knitting machine under zero tension, then it will function as a non-contractible yarn and may be used as such. This will produce a fabric of considerable elasticity, although the elasticity in the weft-wise direction will be limited by the elasticity of the contractible yarn. However, the non-contractible yarn is preferably a non-elastic yarn. Suitable non-elastic yarns include tricel, cotton, polyester, linen, viscose, viscose rayon, viscose acetate, diacetate (e.g. dicel duracol), triacetate (e.g. tricel duracol), polyamides (including nylon), wool, cashmere, alpaca, mohair, viscose/cotton, saran, glass fibres, acrylic yarn, triacetate, camel, merino or silk.
[0011] On the other hand, the choice of contractible yarn is of more significance to the structure of the fabric produced by the present invention, although its influence on the colour, feel, weight and wearing qualities of the fabric will be insignificant, in view of its position between the two layers of fabric. If the contractible yarn is a shrinkable yarn having a large shrinkage or a highly elastic yarn fed under sufficient tension to manifest fully its elasticity, then the puckers formed in the layers of fabric (composed primarily of the non-contractible yarn or yarns) will be bunched very tightly together, with a corresponding reduction in the area of fabric produced from a given length of yarn. On the other hand, if the contractible yarn is a shrinkable yarn having a relatively low shrinkage or is an elastic yarn having a relatively low elasticity or fed under relatively low tension, then the puckers in the fabric formed of the non-contractible yarn will be bunched together much more loosely. Examples of suitable elastic yarns include shirring elastic and various spandex fibres, particularly that sold under the trade name "Lycra". A particularly suitable yarn is a high shrink acrylic yarn. If desired, the elastic yarn may be a covered elastic yarn, in which an elastic yarn (such as those exemplified above) is covered with a wound coat of another (normally non-elastic) yarn, such as nylon yarn.
[0012] In one embodiment of the invention, each pattern row on each of the two layers of fabric is associated with a course of contractible yarn; however, this is not necessary and it is possible (and, indeed, desirable for certain fabric patterns in which the fabric is less puckered in the wale-wise direction) that courses of contractible yarn should be associated with less than every pattern row of the fabric. For example, in one layer of the fabric, the number of pattern rows with which elastic yarn is associated could range from 100% to 1%, e.g. from 100% to 6%, preferably from 20% to 100% and more preferably from 50% to 100%.
[0013] Where the contractible yarn is a shrinkable yarn, the amounts of shrinkable yarn and non-contractible yarn fed for those pattern rows which are associated with the contractible yarn are preferably approximately equal, based on the length of the two yarns prior to shrinkage. Where the contractible yarn is an elastic yarn, the length of the elastic yarn under tension is preferably about the same as the length of that non-contractible yarn, but its length in the relaxed state is necessarily less. A preferred ratio of the relaxed length of elastic yarn to length of non-contractible yarn associated with it (or, which is the same thing, the length of elastic yarn fed under tension) is from 1:5 to 29:30, more preferably from 1:3 to 6:7 and most preferably about 1:4.
[0014] The invention is further illustrated by the accompanying drawings, in which:
Figure 1 shows a needle array for part of three courses of knitting in one embodiment of the invention;
Figure 2 shows a needle array for knitting three courses in another embodiment of the invention;
Figure 3 shows a needle array for knitting four courses in a third embodiment of the invention;
Figure 4 shows the appearance of one face of a double-faced fabric knitted employing a needle array similar to that shown in Figure 1;
Figure 5 shows the surface appearance of one face of a double-faced fabric knitted using a needle array similar to that shown in Figure 2; and
Figure 6 shows the surface appearance of one face of a double-faced fabric knitted using a needle array similar to that shown in Figure 3.
[0015] In all of Figures 1-3, the two needle-beds are shown as 1 and 2, respectively, using standard notation. Each vertical line represents a single needle. Although the vertical lines representing the needles are shown in three different ways, all needles are normally identical, and the different representations are merely provided for ease of counting.
[0016] In a circular knitting machine, for example a cylinder-and-dial machine such as a double Jersey machine, one of the needle beds, for example bed 1, will be the dial, whilst the other, for example bed 2, will be the cylinder. In a flat bed knitting machine, one of the beds, for example bed 1, will be the back bed, whilst the other, for example bed 2, will be the front bed.
[0017] Referring first to Figure 1, the ground fabric is a double-faced jacquard which may be produced, if desired, in at least two colours. Courses A and B are of non-contractible yarn and together form the major part of the face fabric. Courses A and B may be formed of yarns of different colours, providing a two-colour jacquard effect or the two yarns may be of the same colour. If desired, subsequent pattern rows may have the same colour combination or a different combination to achieve varying effects.
[0018] Together, the three courses A, B and C form a single pattern row in each layer of fabric. It can be seen from the drawing that each needle of both needle beds knits either the yarn of course A or the yarn of course B; however, the two courses alternate between being knitted on needle bed 1 and on needle bed 2. As a result, where the two yarns are of different colours, a patterned effect is achieved, for example, as shown in Figure 4, where one of the yarns is white and the other black.
[0019] In course C, which constitutes the elastic yarn, the yarn is knitted on three needles of bed 1 but floats over (miss-knitting) 6 needles and is not knitted at all by needle bed 2. As a result, the elastic yarn of course C is seen on the face of the fabric only on that face produced by needle bed 1, and then only intermittently. No elastic yarn is seen on the face of the fabric produced by needle bed 2.
[0020] In one embodiment of the invention, twelve face courses (A+B) are knitted on all needles using non-contractible yarn. Two courses (as C) are knitted using an elastic yarn. This basic sequence is repeated a sufficient number of times to allow the complete jacquard motif to be developed. The elastic yarn floats are hidden inside the fabric structure and the elastic yarn only appears at those points where it is knitted in. This can be clearly seen in Figure 4, where the knitted in elastic yarn appears as short horizontal black lines.
[0021] Referring now to Figure 2, the ground fabric exhibits either a jacquard motif or an irregular type rib appearance on one face only. In this example, although all needles knit at least one yarn, not all needles knit the non-contractible yarn, as the needles at 3 only knit the elastic yarn of course C. In this case, the face of the fabric formed by needle bed 1 is composed almost entirely of the yarn forming course A, whilst the face of the fabric knitted on needle bed 2 is composed almost entirely of the yarn forming course B. The yarn forming course A appears in the face knitted on needle bed 2 only in one stitch in six. Similarly, the elastic yarn forming course C appears in the face of the fabric knitted on needle bed 1 only at one stitch in six, namely that knitted by needles 3.
[0022] Again, this pattern can repeat and, if desired, courses A+B or A or B may individually repeat any number of times before course C and similarly course C can repeat several times before resuming courses A and B. A fabric produced employing this type of pattern is shown in Figure 5.
[0023] Referring now to Figure 3, this produces a random blister type fabric. The basic repeat is 3 courses (A, B and D) plus one lay-in (course C). Courses A and B, which may be the same or different, knit and float on the needles of bed 2, for example the cylinder needles of a double Jersey machine. The pattern of knitting and floating is determined by the pattern selection and that shown is only by way of example, where each yarn knits on 4 needles and then floats over 2 needles. The float length may vary widely, for example from 1 to 10 needles in different fabrics or even in the same fabric, so as to achieve a more randomized effect. Course D knits on all needles of needle bed 1, for example the dial needles, as well as on those needles of bed 1 floated over (miss-knitted) by courses A and B. Lay-in C constitutes the elastic yarn (courses A, B and D are preferably of non-elastic yarn) and is simply laid-in and not knitted in at all. It is merely trapped in position between the two layers of fabric at those points where course D knits on both beds. The entrapment is, however, sufficiently firm that the elastic yarn remains in position and produces a series of irregular puckers, for example as shown in Figure 6. Similar fabrics may be produced by half-gauging the dial, and/or increasing or decreasing the number of courses A and B in each basic repeat and/or tucking on selected needles on courses A, B and D.
[0024] In all of the examples of fabric described above, especially in relation to the drawings, it should be noted that:
1. A knitted loop may be replaced by a tuck stitch, if desired;
2. Courses A, B, A+B and, where appropriate, D may be repeated several times before course C is knitted or laid in; this can produce interesting blister effects;
3. Course or lay-in C may be repeated several times before courses A, B, A+B and, where appropriate, D are allowed to knit;
4. The needles operating (knitting or tucking) on course C may miss-knit on courses A and B (as, for example, shown in Figure 2);
5. Any of the needles may be held out of action (miss-knit) during all or part of the knitting sequence. This permits the half-gauging of one or both needle beds;
6. The contractible yarn may engage with needles on one or both beds in each of its courses or, as shown in Figure 3, it may engage with none of the needles;
7. The contractible yarn may engage with a varying number of needles and may also float over a varying number of needles.
1. A process for producing a double-faced knitted structure having on one or both
faces a plurality of irregular puckers by knitting on a knitting machine having a
pair of opposed needle beds, characterized in that at least two ends of non-contractible
yarns are knitted on said needle beds to produce at least two knitted courses and
at least one end of a contractible yarn is laid-in between the faces of said double-faced
knitted structure and is intermittently attached to the knitted structure along the
length of said two courses.
2. A process as claimed in Claim 1, wherein said structure has said plurality of irregular
puckers on each said face.
3. A process as claimed in any one of the preceding Claims, wherein said knitting
of non-contractible yarns takes place on all or substantially all (e.g. at least 80%
and preferably at least 90%) of the operating needles of each needle bed.
4. A process as claimed in Claim 3, wherein said knitting of non-contractible yarns
takes place on at least 80% of the operating needles of each needle bed.
5. A process as claimed in Claim 3, wherein said knitting of non-contractible yarns
takes place on at least 90% of the operating needles of each needle bed.
6. A process as claimed in any one of the preceding Claims, wherein from 1% to 50%
of the needles of one needle bed engage the contractible yarn.
7. A process as claimed in Claim 6, wherein from 5% to 30% of the needles of one needle
bed engage the contractible yarn.
8. A process as claimed in Claim 6, wherein from 20 to 25% of the needles of one needle
bed engage the contractible yarn.
9. A process as claimed in any one of the preceding Claims, wherein each pattern row
on each of the two layers of fabric is associated with a course of contractible yarn.
10. A process as claimed in any one of the preceding Claims, wherein, in one layer
of the fabric, the number of pattern rows with which elastic yarn is associated is
from 100% to 1%.
11. A process as claimed in Claim 10, wherein said number is from 100% to 6%.
12. A process as claimed in Claim 10, wherein said number is from 20% to 100%.