METHOD FOR MANUFACTURING A WEFT KNIT FABRIC AND FABRIC OBTAINED WITH THE METHOD

The present invention relates to a method for manufacturing a weft knit fabric composed of adjacent or contiguous portions of rows of knitting knitted with a different number of yarns, without floated yarns, with a knitting machine for knitting with reciprocating motion, and to a fabric obtained with the method.

More particularly, the present invention relates to a method for providing a fabric similar to the knit fabric type called "floated vanise", but without floated yarns, in order to obtain sheer, color or raised effects.

As known, in knitting, the term "floated vanise" is understood to be a particular structure of weft knitting that is provided by knitting portions of the knit fabric by using two yarns that are dispensed at a same feed or drop and are mutually different in terms of type and/or color and/or dimensions, and other portions of knit fabric by using only one of these two yarns so as to create sheer, color, or raised knitting effects that vary from one region of the fabric to another.

In order to provide this particular knitting, in the case of circular knitting machines, at the feed or feeds of the machine to be used, the two yarns to be knitted are delivered by means of respective yarn fingers that are arranged at mutually different height levels and the needles of the needle cylinder, at this feed, in the movement for taking up the yarn or yarns, can be arranged at two mutually different height levels (dropped level and tuck level). This arrangement of the yarn fingers and this diversified actuation of the needles causes a yarn (called "vanise" or "bed") to be picked up and knitted in by all the needles, both those arranged at the tuck level and those arranged at the dropped level, while the other yarn (called "color bed") is picked up and knitted in only by the needles arranged at the dropped level. This yarn, at the needles arranged at the tuck level, is not knitted in and remains "floated" on the reverse side of the fabric until it is picked up by one or more subsequent needles.

In "floated vanise" knitting of the known type, the floated yarns form bridge loops on the reverse side of the fabric. These bridge loops reduce the sheer or color effect that one desires to obtain with this particular knitting and they can be uncomfortable for the user.

In many cases, particularly when they have a considerable extension, these bridge loops are removed by cutting, leaving trailing portions of yarn at the cut ends.

The presence of these trailing portions can also be unsightly or uncomfortable for the user. Moreover, the cutting of the floated yarns requires generally the execution of weaves in order to contrast the laddering of the cut yarns.

The aim of the present invention is to solve the problems cited above, by devising a method that allows to manufacture a weft knit fabric composed of adjacent or contiguous portions of rows of knitting knitted with a different number of yarns, without floated yarns or trailing portions.

Within this aim, an object of the invention is to devise a method that allows to manufacture a knit fabric of the type called "floated vanise", but without floated yarns or trailing portions on the reverse side, in order to obtain particular sheer, color or relief effects.

Another object of the invention is to devise a method that can be performed on weft knitting machines provided with a needle holder that can be actuated with a reciprocating motion with respect to one or more feeds or drops.

A further object of the invention is to devise a method that, thanks to the absence of floated yarns or trailing portions on the reverse side of the knit fabric, allows to manufacture knit fabric of higher quality than "floated vanise" knit fabrics of the known type.

This aim and these and other objects that will become better apparent hereinafter are achieved by a method for manufacturing a weft knit fabric composed of adjacent or contiguous portions of rows of knitting knitted with a different number of yarns, without floated yarns, with a knitting machine for knitting with reciprocating motion, consisting in:

- having a weft knitting machine with at least one feed or drop and with a needle holder that supports a plurality of needles that can be actuated to pick up the yarns dispensed by said at least one feed and to form knitting; said needle holder being movable with respect to said at least one feed along a path and said at least one feed being arranged proximate to said path; said needle holder being actuatable with respect to said at least one feed along said path with a reciprocating motion, i.e., along two mutually opposite directions of motion, respectively a forward motion and a return motion, in order to move the needles so that they face in succession said at least one feed both in the forward motion and in the return motion of said needle holder with respect to said at least one feed; at said at least one feed or drop there being at least two yarn fingers adapted to dispense at least two yarns that are mutually spaced parallel to the direction of motion of said needles with respect to said needle holder in forming the knitting;

- identifying, in said needle holder, at least two contiguous or adjacent sectors, respectively a first sector and a second sector, each of which accommodates corresponding needles that can be actuated at said at least one feed to pick up at least one yarn dispensed by said at least one feed and form knitting;

characterized in that it comprises a main knitting step that consists in:

- actuating the needle holder with respect to said at least one feed with reciprocating motion, making said first sector and said second sector pass in sequence in front of said at least one feed and vice versa;

- moving to knit, during the forward motion of the needle holder, the needles of said first sector at said at least one feed to pick up said at least two yarns, dispensed by said at least one feed, and form knitting;

- moving to knit, during the forward motion of the needle holder, the needles of said second sector at said at least one feed to pick up a number of yarns, dispensed by said at least one feed, that is smaller than the number of yarns picked up by the needles of said first sector and form knitting;

- moving to knit, during the return motion of the needle holder, the needles of said second sector and the needles of said first sector at said at least one feed to pick up the same yarns that they picked up during the forward motion of the needle holder and form knitting.

Further characteristics and advantages of the present 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 in the accompanying drawings, wherein:

Figure 1 is a view of the knitting pattern of a portion of fabric, manufactured with the method according to the invention, viewed from the reverse side;

Figure 2 is an enlarged-scale view, taken from the reverse side, of a detail of a portion of fabric, manufactured with the method according to the invention and deriving from the knitting steps indicated in the frame X of the pattern of Figure 1 .

With reference to the figures, the method according to the invention is performed by using a weft knitting machine with at least one feed or drop and with a needle holder that supports a plurality of needles that can be actuated to pick up yarns dispensed by said feed or other feeds, if provided, in order to form knitting.

The needle holder can be actuated with respect to the at least one feed along a path that is rectilinear in the case of a rectilinear machine or is circular in the case of a circular machine.

The needle holder can be actuated with respect to the at least one feed along this path with a reciprocating motion, i.e., according to two mutually opposite directions of motion, respectively a forward motion and a return motion, so as to move the needles so that they face in succession the at least one feed both in the forward motion and in the return motion of the needle holder with respect to the at least one feed.

At the at least one feed there are at least two yarn fingers adapted to dispense, in a per se known manner, at least two yarns that are mutually spaced parallel to the direction of motion of the needles with respect to the needle holder in forming the knitting.

At least two contiguous or adjacent sectors, respectively a first sector A and a second sector B, are identified in the needle holder, and each one of these sectors accommodates corresponding needles that can be actuated at the at least one feed to form knitting.

Preferably, the machine is constituted by a circular knitting machine and therefore the needle holder is constituted by the needle cylinder of the machine that is arranged so that its axis is vertical and can be actuated with a rotary motion about its own axis with respect to the at least one feed that is used to perform the method according to the invention.

In this case, the needle holder, which is constituted by the needle cylinder, traces a circular path about its own axis and the at least one feed faces laterally the needle cylinder and is arranged proximate to the path described by the needle cylinder during rotation so as to provide the yarn or yarns to the needles that are moved to knit at said feed and are actuated to form knitting.

The needle cylinder can be actuated, in a per se known manner, with a reciprocating rotary motion about its own axis so as to form knitting both in the forward motion and in the return motion.

Since this is a circular machine, the sectors in which the needles selected to knit at the at least one feed are arranged are constituted by contiguous portions of the curved surface of the needle cylinder.

The method according to the invention comprises a main knitting step L2 that consists in actuating the needle holder, i.e., the needle cylinder, with respect to the at least one feed with a reciprocating rotary motion about its own axis, making the first sector A and the second sector B pass in sequence in front of the at least one feed and vice versa. During the forward motion of the needle holder, the needles of the first sector A are moved to knit at the at least one feed to pick up at least two yarns F l , F2 dispensed by said feed and form knitting. Also during the forward motion of the needle holder, the needles of the second sector B are moved to knit at the same feed but so as to pick up a number of yarns that is smaller than the number of yarns picked up by the needles of the first sector A and form knitting. During the return motion of the needle holder, the needles of the second sector B, which are the first to pass at the at least one feed, and the needles of the first sector A, which pass subsequently at the same feed, are moved to knit at this feed so as to pick up the same yarns that they picked up during the forward motion of the needle holder and form knitting.

In the illustrated example, three contiguous sectors of the needle cylinder, respectively a first sector A, a second sector B and a third sector C are used, with the second sector B arranged between the first sector A and the third sector C, and two feeds that are mutually angularly spaced around the axis of the needle cylinder.

In the knitting pattern shown in Figure 1, each vertical column of squares refers to a needle and each square represents an actuation mode of a needle. For the sake of simplicity, only the vertical columns necessary to describe the method according to the invention have been designated by the numerals 1 to 28. In this figure, the sectors A, B, C of the needle holder are divided by means of vertical lines thicker than the others.

A square with a central dot indicates that the corresponding needle is moved to the dropped level so as to pick up at least two yarns F l , F2 dispensed at two different height levels at the first feed; a white square indicates that the corresponding needle, after moving the loop of knitting present on its stem below the latch, is moved to the tuck level in order to pick up, at the first feed, only the yarns F2 dispensed at the lower height level and not pick up the yarn F l , therefore so as to pick up a number of yarns that is smaller than the number of yarns that are picked up by the needles arranged at the dropped level; a square with a diagonal indicates that the corresponding needle is moved to knit at the second feed in order to pick up the yarn or the yarns F3, F4 dispensed by said second feed.

For the sake of simplicity, the description that follows assumes that only two yarns Fl , F2 are dispensed at mutually different height levels at the first feed.

Moreover, it is assumed that two yarns F3, F4 are dispensed at the second feed, similarly to what occurs at the first feed, and that the needles that are moved to knit at this second feed are moved to knit at the dropped level so as to pick up both the yarns F3, F4 dispensed by this feed.

In practice, the needles of the first sector A are moved to knit at the first feed at the dropped level so as to pick up both the yarns Fl , F2 dispensed by this first feed, while the needles of the second sector B are moved to knit at the first feed at the tuck level so as to pick up only the yarn F2 dispensed by this feed.

The needles of the third sector C are moved to knit at the second feed at the dropped level so as to pick up both of the yarns F3, F4 dispensed by this second feed.

In Figure 2, the rows of loops of knitting that due to space requirements have been reduced with respect to the corresponding rows of needles shown in Figure 1 , have been designated by the same numerals with which the vertical columns of squares that correspond to the needles that form these rows of loops of knitting have been designated.

In Figure 2, the portions of knit fabric knitted by the needles located in the sectors A, B, C, have been designated by the letters A', B', C

For the sake of simplicity, where necessary for the explanation of the invention, the needles of the various sectors will be designated by the same numeral as the row of loops of knitting that they form and thus by the same numeral that, in the pattern of Figure 1 , identifies the corresponding vertical column.

The method according to the invention, in the illustrated embodiment, comprises preferably a preliminary knitting step L I , in which the needle holder is actuated with a reciprocating motion with respect to the feeds and the needles of the first sector A and of the second sector B are actuated at the first feed at the dropped level so as to pick up both of the yarns F l , F2 dispensed by this feed. In this preliminary knitting step L I , the needles of the third sector C are actuated at the second feed so as to pick up the two yarns F3, F4 dispensed by this second feed.

The main knitting step L2 is then performed in which the needle holder is actuated, with respect to the feeds, with a reciprocating motion, making the first sector A and the second sector B pass in sequence in front of the first feed and vice versa. During the forward motion of the needle holder, the needles of the first sector A are moved to knit at the first feed at the dropped level so as to pick up both of the yarns F 1 , F2 dispensed by this feed and form knitting. Also during the forward motion of the needle holder, the needles 4-25 of the second sector B are moved to knit at the first feed at the tuck level so as to pick up only one yarn, constituted by the yarn F2, of the two yarns F l , F2 dispensed by this first feed.

It should be noted that, during this forward motion, while the needles 4-25 of the second sector B are knitting at the first feed, the yarn F l that is not picked up by the needles 4-25 of the second sector B remains hooked to the needles of the first sector A and extends freely from the last needle 26 of the first sector A that picked it up to the corresponding yarn finger arranged at the first feed. During the return motion of the needle holder, the needles 4-25 of the second sector B and the needles of the first sector A are moved to knit at the first feed in order to pick up the same yarns F2, F l that they picked up during the forward motion of the needle holder and form knitting. In practice, the needles 4-25 of the second sector B pick up only the yarn F2, while the needles of the first sector A pick up the two yarns F l , F2.

In this manner, the portion of yarn F 1 that has not been picked up by the needles 4-25 of the second sector B and extended freely from the last needle 26 of the first sector A that picked it up, is taken up progressively by a take-up device of the known type located upstream of the corresponding yarn finger and then picked up by the needles of the first sector A and used to form a subsequent row of knitting, formed during the return motion of the needle holder. By way of this fact, no bridge loop of floated yarn remains on the reverse side of the knit fabric.

During the forward motion and during the return motion of the needle holder, the needles of the third sector C are moved to knit at the second feed to pick up at least the two yarns F3, F4 dispensed by this second feed and form knitting.

The main knitting step L2 can be followed by a final knitting step, not shown, in which, similarly to the preliminary knitting step L I , the needle holder is actuated with a reciprocating motion with respect to the feeds, and the needles of the first sector A and of the second sector B are actuated at the first feed at the dropped level so as to pick up both of the yarns F 1 , F2 dispensed by said feed. In this final knitting step, the needles of the third sector C are actuated at the second feed so as to pick up the two yarns F3, F4 dispensed by this second feed.

It should be noted that, in order to join the portion of fabric manufactured by the needles of the first sector A and of the second sector B by means of the yarn or yarns F l , F2 dispensed by the first feed to the portion of fabric manufactured by the needles of the third sector C by means of the yarns F3, F4 dispensed by the second feed, a needle, constituted by the needle 4, of the second sector B that is adjacent to the third sector C, as shown, or the needle 3 of the third sector C that is adjacent to the second sector B, is made to knit alternatively at the first feed and at the second feed obtaining the seam shown in Figure 2 along the row of loops of knitting 4. The seam between the portions of knit fabric knitted at two different feeds can be obtained also with other methods of the known type or according to the method disclosed in Italian patent application MI2013A001983 by the same Applicant.

With the method according to the invention, by dispensing at the first feed two yarns F l , F2 that are mutually different in diameter and/or color, at two different height levels it is possible to obtain a knit fabric with decorative sheer and/or color and/or raised effects.

For example, if two yarns F l , F2 are dispensed at the first feed at two different height levels, respectively a first yarn F l of larger diameter at an upper level and a second yarn F2 of smaller diameter at a lower level, so that the yarn F2 of smaller diameter is picked up both by the needles of the first sector A and by the needles of the second sector B, while the yarn F l of larger diameter is picked up only by the needles of the first sector A, the portion of fabric knitted only with the second yarn F2 is more sheer. This sheer effect, with the method according to the invention, is highlighted by the fact that on the reverse side of the fabric there are no bridge loops of the first yarn F l or trailing portions, which in knit fabrics manufactured with traditional methods show inevitably through the fabric.

If a color effect using yarns of different color is sought, the effect obtained with the method according to the invention is increased, since the contrast between the portions of fabric of different color is sharper because there are no bridge loops or trailing portions of different color on the reverse side of the fabric.

It should be noted that the sectors of needles that are moved to knit may occupy all the lateral surface of the needle cylinder or only one portion thereof. Moreover, two contiguous portions of fabric knitted at different feeds may be mutually joined, by means of joining methods of the known type, obtaining a fabric that is closed on itself, i.e., a tubular fabric, or kept free, obtained an open sheet. In particular, the method according to the invention can be performed also by using only a single feed, for example by using, with reference to the example shown, only the first feed and the first sector A and the second sector B.

In the embodiment shown, it is assumed that the width of a sector and therefore the number of needles moved to knit at a feed is not changed during the reciprocating motion of the needle holder, unless the needle that forms the row of loops of knitting 4 is made to knit alternatively at two feeds in order to perform occasionally the joining of two portions of fabric. In this manner, the borders of the portions of fabric knitted by needles belonging to different sectors are parallel to the extension of the rows of loops of knitting, as shown.

However, the method according to the invention can be performed by varying the width of the sectors at each forward and return cycle of the needle holder so that the borders of the portions of fabric knitted by needles belonging to different sectors are inclined with respect to the extension of the rows of loops of knitting. In this manner it is possible to shape according to preset drawings the portions of the fabric that differ from each other due to the number of yarns used.

The number of yarns dispensed at the dropped level and the number of yarns dispensed at the tuck level at the various feeds of the machine can vary according to the requirements.

It should be noted, moreover, that the number of sectors and the number of the feeds can vary according to the requirements. Thus, for example, it is possible to provide a fourth sector, the needles of which are actuated to pick up at the second feed a number of yarns that is smaller than the number of yarns picked up by the needles of the third sector. In practice it is possible to move to knit at the second feed the needles of the third sector and of the fourth sector in a manner similar to the actuation of the needles of the first sector A and of the second sector B at the first feed. In this manner, a fabric is obtained with two portions that are more sheer or of a color alternated with two denser portions or of another color or shade of color.

Finally, the pickup, by the needles of the second sector and/or of the optional fourth sector or of further sectors, of a number of yarns smaller than the number of yarns picked up at the same feed by the needles of a contiguous or adjacent sector may be limited by the forming of some rows or knitting, depending on the effects that one wishes to obtain.

In practice, the knit fabric that is obtained with the method according to the invention is composed of adjacent or contiguous portions of rows of knitting that are knitted with a different number of yarns, without floated yarns. Such knit fabric comprises at least one first portion of fabric 50 composed of portions of rows of knitting knitted with a number of yarns F l , F2 and at least one second portion of fabric 51 , which is contiguous or adjacent to the first portion of fabric and is composed of portions of rows of knitting knitted with only one part F2 of the yarns F l , F2 of the portions of rows of knitting of the first portion of fabric. The yarn F l or the yarns of the portions of rows of knitting of the first portion of fabric 50 in excess with respect to the yarns F2 of the portions of rows of knitting of the second portion of fabric 51 , at the ends of each portion of row of knitting of the first portion of fabric 50, continue in the following portion of row of knitting of the first portion of fabric 50 and are part of the loops of knitting that compose the following portion of row of knitting of the first portion of fabric 50.

In practice it has been found that the method according to the invention fully achieves the intended aim, since it allows to produce a weft knit fabric composed of adjacent or contiguous portions of rows of knitting knitted with a different number of yarns, without floated yarns or trailing portions. In this manner it is possible to provide a knit fabric of the "floated vanise" type, but with contrast effects between the portions knitted with a different number of yarns that are substantially greater than the contrast effects that can be obtained with the traditional method indeed by way of the absence of floated yarns or trailing portions in the knit fabric manufactured with the method according to the invention.

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. MI2014A000967, from which this application claims priority, ' are incorporated herein by reference.

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