The present invention relates to a method for providing intarsia designs with a weft knitting machine and to a weft knitted fabric with intarsia design that can be obtained with the method.

As known, in the weft knitting field, the expression "intarsia design" is understood to reference a design, composed of regions provided with yarns that are mutually different in terms of color or type, that does not have floating yarns on the reverse side, i.e., yarns for connecting the portions of a same row of knitting that are mutually spaced one another and are each provided by means of its own yarn, and does not have cuts of yarns at the ends of each row portion that composes a region of the design.

Intarsia designs are performed with rectilinear machines or circular machines for knitting or hosiery that allow to move the feeds or drops, at which the yarns are dispensed, with respect to the needle holder, whether constituted by a rectilinear needle bed or by a cylinder, or vice versa, i.e., that allow to move the needle holder with respect to the feeds or drops, according to two mutually opposite directions of motion, i.e., with a forward motion and a return motion.

Usually, the intarsia design is performed, during the production of each row of knitting that composes the design, by correlating one group of needles and making it knit at one feed and by correlating another group of needles, which is adjacent or contiguous, and making it knit at another feed. The number of the feeds and of the groups of needles correlated with them can vary according to the number of mutually different regions of the design to be provided and the number of needles for each group of needles can be varied from row to row in order to vary the shape of the different regions of the design to be provided.

The alternating motion of the needle holder with respect to the feeds of the machine is the solution that allows to knit portions of rows of knitting with yarns that are mutually different in terms of color or type without having to cut the yarns at the end of the corresponding portion of row of knitting and without leaving long floating pieces, on the reverse side, with the yarns that are not used in the knitting of a contiguous portion of a row of knitting, which are waiting to be used again for the formation of a further portion of row of knitting.

Two adjacent regions of knitting knitted with mutually different yarns dispensed at two different feeds are joined by making a needle, arranged at the border of the two regions, knit both at the feed correlated with its own group of needles and at the feed correlated with the adjacent or contiguous group of needles. The needle being considered can form stitches of the dropped type or stitches of the tuck type, according to the requirements.

The intarsia designs provided in this manner, however, have the problem of poor visual definition of the separation line between two adjacent regions of the design because along the row of border knitting loops, provided with the needle that knits at both feeds used for the production of the two adjacent regions, loops or stitches provided with the yarn or yarns of one feed and stitches provided with the yarn or yarns of the other feed are mutually alternated.

The aim of the present invention is to solve this problem, devising a method for providing intarsia designs with a weft knitting machine that allows to obtain qualitatively better results than those obtainable with the methods currently used.

Within this aim, an object of the invention is to propose a method that allows to obtain a greater visual definition at the border lines of the various regions that compose the intarsia design.

Another object of the invention is to propose a method that can be performed, in particular, on circular weft knitting machines, which typically have clearly superior productivities than rectilinear machines. This aim and these and other objects that will become better apparent hereinafter are achieved by a method for providing intarsia designs with a weft knitting machine, consisting in:

- having a weft knitting machine with at least two feeds or drops and with a needle holder that supports a plurality of needles that can be actuated to pick up the yarns dispensed by said feeds and to form knitting; said needle holder being movable with respect to said feeds along a trajectory and said feeds being arranged in sequence along said trajectory; said needle holder being actuatable with respect to said feeds along said trajectory in two mutually opposite directions of motion, respectively a forward motion and a return motion, in order to make the needles face in succession said two feeds and form knitting both in the forward motion and in the return motion of said needle holder with respect to said feeds;

- providing, for the formation of each row of knitting of the intarsia design to be produced, for the use of at least two adjacent groups of needles, which must produce corresponding adjacent portions of the same row of knitting of two regions of the intarsia design with yarns that are mutually different in terms of color or type, and correlating each one of said two groups of needles with a corresponding feed between said two feeds;

characterized in that the needles of one group of needles pick up the yarn or yarns dispensed exclusively by the feed with which said group of needles is correlated, and in that the two portions of a same row of knitting produced by said two groups of needles during the forward motion or during the return motion of said needle holder are produced in sequence by making the needles of one group of needles of said two groups of needles knit, in a first step, at the feed with which it is correlated, and then, in a second step that is subsequent to said first step, the needles of the other group of needles knit at the feed with which it is correlated, the extent of the motion in the two directions of said needle holder being such as to allow the completion of said two steps. Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of the method according to the invention, illustrated by way of non-limiting example with the aid of the accompanying drawings, wherein:

Figures 1 to 3 are views of a method for providing an intarsia design of the known type, more particularly:

Figure 1 is a schematic view of a portion of fabric with an intarsia design seen on the reverse side;

Figure 2 is a schematic view of the knitting, seen on the reverse side of the fabric, at the detail of Figure 1 designated by X', suitably enlarged;

Figure 3 is a schematic view of the arrangement of the groups of needles and of the feeds or drops used to provide the intarsia design on a circular knitting machine;

Figures 4 to 6 are views of a method for providing an intarsia design according to the invention, more particularly:

Figure 4 is a schematic view of a portion of fabric with an intarsia design, seen from the reverse side;

Figure 5 is a schematic view of the knitting, seen from the reverse side of the fabric, at the detail of Figure 4 designated by X, suitably enlarged;

Figure 6 is a schematic view of the arrangement of the groups of needles and of the feeds or drops used for providing the intarsia design on a circular knitting machine.

In order to better explain the method according to the invention and to allow understanding of its innovative particularities with respect to methods of the known type, a method for providing an intarsia design of the known type with a circular knitting machine will be explained first with reference to Figures 1 to 3.

Figure 1 shows a portion of knitted fabric Γ, seen from the reverse side, with an intarsia design 2' that is composed of two regions 3', 4' provided with yarns that are mutually different in terms of color and/or type. The remaining part of the knitted fabric is designated generally by the numeral 5'.

In order to provide the intarsia design 2' composed of the regions 3', 4', by means of a circular knitting machine provided with a needle cylinder 6' that can be actuated with an alternating rotary motion about its axis 7' with respect to the feeds or drops 1 , 12', 13', 14' that are arranged, angularly spaced with respect to each other, about the axis V of the needle cylinder 6', and facing laterally the needle cylinder 6', two groups of needles are chosen, respectively a first group of needles 23' and a second group of needles 24', which are adjacent or contiguous and are correlated with two different feeds of the machine, constituted, in the case shown, by the feeds 13' and 14'. The term "correlated" is understood to mean that the needles that belong to a group of needles correlated to one feed are moved to knit and form knitting at said feed.

The machine is provided with at least two feeds. In the case shown, the machine is provided with four feeds, designated by the reference numerals 11', 12', 13', 14'.

The two adjacent or contiguous groups of needles used for the production of the regions 3', 4' of the design 2' are designated by the reference numerals 23' and 24' and are correlated respectively with the feeds 13', 14'.

For the sake of simplicity, in Figure 3 the reference numerals 23', 24', 25' designate the sectors of the needle cylinder 6' in which the two groups of adjacent needles are arranged which are used respectively to produce the regions 3', 4' of the design 2' and the remaining part 5' of the knitted fabric 1'.

In the methods of the known type, the needle cylinder 6' is actuated with an alternating rotary motion about its own axis V with respect to the feeds 1 Γ, 12', 13', 14' with a forward motion and a return motion. During the forward motion, hypothetically in a counterclockwise direction, the needles of the first group 23' are moved to knit at the feed 13' and the needles of the second group 24' are moved to knit at the feed 14'. In the return motion, hypothetically in a clockwise direction, the needles of the second group 24' are moved to knit again at the feed 14' and the needles of the first group 23' are moved to knit again at the feed 13'.

It should be noted that the arrangement of the feeds 13', 14' around the axis V of the needle cylinder 6' and the arrangement of the two groups of needles 23' and 24' is such that both in the forward motion and in the return motion of the needle cylinder 6' about its own axis V with respect to the feeds 13', 14', when the first group of needles 23' faces the feed 13' with which it is correlated, the second group of needles 24' faces the feed 14' with which it is correlated. For this reason, in the methods of the known type, one can consider that the needles of the first group 23' and the needles of the second group 24' knit simultaneously at the feeds 13', 14' with which they are correlated. Moreover, at least one needle arranged proximate to the border between the two groups of needles 23', 24' knits both at the feed 13' and at the feed 14', ensuring the joining between the two regions 3', 4' of the design 2'.

Figure 2 shows an enlarged detail of Figure 1 related to the portion of fabric that straddles the regions 3', 4'. For the sake of simplicity, eleven rows of knitting loops, produced by as many needles and designated by the letters a'-m', are shown.

In the example shown, the needle that knits at both of the feeds is the one that forms the row of knitting loops designated by the letter f ' and conceptually can belong equally to the first group of needles 23' or to the second group of needles 24'.

As can be seen in Figure 2, the joining between the two regions 3', 4' of the design 2' derives indeed from the fact that a needle knits at both of the two feeds 13', 14' used to provide the intarsia design 2'. The row of knitting loops f ' provided by this needle is therefore composed alternately of a loop of knitting formed with the yarn or yarns supplied by the feed 13' and a loop of knitting formed with the yarn or yarns supplied by the feed 14'.

For this reason, the line of separation between the two regions 3', 4' is not well defined visually.

Figure 4 shows a portion of knitted fabric 1 , seen from the reverse side, with an intarsia design 2 that is provided by means of the method according to the invention and, similarly to the intarsia fabric 2', is composed of two regions 3, 4 provided with mutually different yarns in terms of color and/or type. The remaining part of the knitted fabric 1 is designated generally by the reference numeral 5.

For the execution of the method according to the invention, a weft knitting machine is used, in a manner similar to what happens in the methods of the known type, which has at least two feeds and a needle holder that is provided with a plurality of needles that can be actuated to pick up the yarn or yarns at said feeds and form knitting. In the example shown in Figures 4 to 6, the machine is constituted by a circular knitting machine with four feeds 1 1, 12, 13, 14 that are mutually angularly and regularly spaced around the axis 7 of the needle cylinder 6 that constitutes the needle holder.

The needle cylinder 6 can be actuated with a rotary motion about its own axis 7 with respect to the feeds 11, 12, 13, 14 so as to make the needles transit progressively in front of the feeds 11, 12, 13, 14 that are arranged in sequence along the circular trajectory followed by the needle cylinder 6 in its rotation.

The needle cylinder 6 can be actuated with respect to the feeds 11, 12, 13, 14 with an alternating rotary motion about its own axis 7, respectively according to a forward motion and according to a return motion, in order to make the needles face in succession the feeds 11, 12, 13, 14 of the machine, particularly the two feeds 13, 14, and the needles can be actuated, in a per se known manner, to form knitting both in the forward motion and in the return motion of the needle cylinder with respect to the feeds.

In order to form each row of knitting of the design 2 to be produced, two adjacent or contiguous groups of needles 23, 24 are used, respectively a first group of needles 23 and a second group of needles 24, which must produce corresponding adjacent portions of adjacent regions 3, 4 of the design 2 with yarns that are mutually different in terms of color or type. Each one of the two groups of needles 23, 24 is correlated with a corresponding feed, respectively with the feed 13 and with the feed 14 of the two feeds 13, 14.

For the sake of simplicity, in Figure 6 the numerals 23, 24 and 25 designate the sectors of the needle cylinder 6 in which the groups of needles are arranged which are used respectively to produce the regions 3, 4 of the design 2 and the remaining part 5 of the knitting fabric 1.

According to the invention, the needles of one group of needles 23,

24 pick up the yarn or yarns dispensed exclusively by the feed 13, 14 with which the group of needles 23, 24 is correlated and the two portions of a same row of knitting produced by the two groups of needles 23, 24 during the forward motion or during the return motion of the needle cylinder 6 are produced in sequence by making the needles of one of the two groups of needles 23, 24 knit, in a first step, at the feed 13, 14 with which they are correlated and then, in a second step that is subsequent to the first step, by making the needles of the other group of needles 24, 23 knit at the feed 14, 13 with which they are correlated.

The extent of rotation in the two directions of the needle cylinder 6 is such as to allow the completion of the two steps cited above.

With particular reference to Figures 4 to 6, the group of needles 23 knits exclusively at the feed 13, while the group of needles 24 knits exclusively at the feed 14.

The remaining needles 25 and the remaining feeds 11, 12 are not used or are used to produce regions of the knitted fabric 1 that are external to the intarsia design 2 being described. The methods of production of the regions 5 of the knitted fabric 1 that are external to the intarsia design 2 may be performed by means of methods and techniques of a known type and are not described for the sake of simplicity.

Conveniently, the arrangement of the two groups of needles 23, 24 in the needle cylinder 6 and the arrangement of the feeds 13, 14 is such that at the beginning of the forward motion (hypothetically in a counterclockwise direction) of the needle cylinder 6 with respect to the feeds 13, 14, the group of needles 23 transits first in front of the feed 13 with which it is correlated and then in front of the feed 14, while at the beginning of the return motion (hypothetically in a clockwise direction) the other group of needles 24 transits first in front of the feed 14 with which it is correlated and then in front of the feed 13, as will become better apparent hereinafter.

In greater detail, during the motion or rather during the forward rotation (in a counterclockwise direction) of the needle cylinder 6 about its own axis 7 with respect to the feeds 11, 12, 13, 14, the needles of the first group 23 transit first in front of the feed 13 with which said group of needles is correlated. In this first step, the needles of the first group of needles 23 pick up the yarn or yarns dispensed by the feed 13 and form knitting. The needles of the second group of needles 24 transit in front of the feed 14 with which said group of needles is correlated only after that the last needle of the first group of needles 23 has picked up and knitted the yarn or yarns at the feed 13. The needles of the second group of needles 24 are then actuated in order to pick up the yarn or yarns dispensed by the feed 14 and form knitting only in a second step that is subsequent to the first step.

During the motion or rather during the return rotation (in a clockwise direction) of the needle cylinder 6 about its own axis 7 with respect to the feeds 11, 12, 13, 14, the needles of the second group 24 are the ones that transit first in front of the feed 14 correlated with said group of needles that are actuated, in a first step, in order to pick up the yarn or yarns dispensed by the feed 14 and to form knitting.

The needles of the first group of needles 23 transit in front of the feed 13 with which said group of needles is correlated only after the last needle of the second group of needles 24 has picked up and knitted the yarn at the feed 14. The needles of the first group of needles 23 are then actuated in order to pick up the yarn or yarns dispensed by the feed 13 and form knitting only in a second step that is subsequent to the first step in which the needles of the second group of needles 24 have knitted.

The result that is achieved with the method according to the invention proximate to the joining line between the two regions 3, 4 that compose the intarsia design 2 is shown in Figure 5, in which the rows of knitting knitted by eleven contiguous needles are shown and are designated by the letters a- m.

As can be seen, the joining between the two regions 3, 4, unlike what occurs with the methods of the known type, is obtained by crossing the yarns provided by the two feeds 13, 14 following the reversal of the motion of the needle holder 6 and because the portions of each one of the rows of knitting that compose the two regions 3, 4 of the intarsia design 2 are knitted not simultaneously, but in sequence, i.e., one after the other.

By means of the method according to the invention, the crossing of the yarns that compose the two regions 3, 4 is located in the region comprised between the two rows of knitting loops f, g formed respectively by one needle of the first group of needles 23 and by one needle of the second group of needles 24. For this reason, with the method according to the invention, a greater definition and sharpness in the demarcation of the two regions 3, 4 that compose the intarsia design 2 is obtained.

In practice, if the two regions 3,4 are provided with mutually different yarns in terms of color, the regions 3, 4 have a sharpness of the color with a clear dividing line, i.e., the two colors do not mix or interfere with each other.

It is important to note that the crossing of the yarns that joins the regions 3, 4 affects the sides of the knitting loops or interloops arranged at the border between the two regions 3, 4.

Thanks to the fact that the crossing of the yarns that joins the two regions 3, 4 affects the sides of the knitting loops or interloops arranged at the border between the two regions 3, 4, it is possible to provide the two contiguous regions 3, 4 as if they were "isolated" from each other by producing them with yarns having completely different characteristics and therefore it is possible to ensure the full efficiency and quality of the regions 3, 4 taken individually.

For greater clarity, the description of a method of a known type and the description of the method according to the invention have been limited to an intarsia design composed of two regions provided with mutually different yarns in terms of color or type, but the number of regions may vary according to the requirements and if a suitable number of feeds is available on the production machine or by performing appropriate changes of yarn carriers on the drops provided on the machine.

Again for greater clarity, the border line between the two regions 3, 4 has been considered parallel to the rows of knitting loops produced by the needles, i.e., perpendicular to the rows of knitting, but this line may also be inclined or have another shape, more generally a spline-like shape, varying, in a per se known manner, the number of needles that belong to a group of needles and varying correspondingly the needles of the adjacent group of needles.

Although the basic concept of the invention has been illustrated for a circular knitting machine, it can be applied also to rectilinear machines provided with a rectilinear needle holder that can be actuated with alternating motion along a rectilinear trajectory with respect to feeds arranged along said trajectory or vice versa.

In practice it has been found that the method according to the invention fully achieves the intended aim, since it allows to produce intarsia designs that have a greater visual definition in the demarcation between the regions that compose them and therefore are qualitatively better than those that can be obtained with methods of the known type.

The method thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other technically equivalent elements.

In practice, the materials used, as well as the dimensions, may be any according to requirements and to the state of the art.

The disclosures in Italian Patent Application No. MT2013A001983 from which this application claims priority are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.