WO2012014246A1

WO2012014246A1 - A method and a machine for knitting a garment and a garment obtained thereby

Info

Publication number: WO2012014246A1
Application number: PCT/IT2011/000269
Authority: WO
Inventors: Nerino Grassi; Carlo Casini
Original assignee: Golden Lady Co SpA
Current assignee: Golden Lady Co SpA
Priority date: 2010-07-30
Filing date: 2011-07-27
Publication date: 2012-02-02
Anticipated expiration: 2013-01-30
Also published as: ITFI20100165A1; TW201207180A; IT1401279B1

Abstract

The knitted garment comprises a body portion (1) and two leg portions (9 A, 9B) joined along a crotch line (CC). The body portion and the leg portions are formed of a seamless, continuous knitted fabric with a joining line (CC) in the crotch area between the two leg portions formed of at least a partial interknitted course common to the two leg portions. The common interknitted course includes a partial fabric starting course on one of said two leg portions, to which float stitches formed on a partial fabric starting course on the other of said two leg portions are interknitted.

Description

"A METHOD AND A MACHINE FOR KNITTING A GARMENT AND A GARMENT OBTAINED THEREBY"

DESCRIPTION

Technical field

The invention refers to a method and a machine for knitting garments such as pants, pantyhose or the like and, more in general, knitted garments comprising a body portion and two leg portions.

State of the art

The method currently most often used to manufacture pantyhose or the like involves knitting two knitted fabric tubes on a single-cylinder circular knitting machine, then cutting them lengthwise in line with the area of the pants, and joining them together by sewing their respective cut portions together. The resulting pantyhose afford a good wearability, but the presence of the seams is aesthetically unattractive and uncomfortable for the wearer, particularly in the area of the groin. In some cases, a patch of fabric is stitched to the groin area of the garment to obtain a more comfortable fit, but this increases the cost of manufacturing the pantyhose.

To overcome these drawbacks, various methods and corresponding knitting machines have been developed to produce pantyhose that, when they are detached from the machine, are ready to wear and do not require further sewing processes in the pants area or body portion of the garment.

One such method is described, for instance, in US 4011738, issued on 15/3/1977, and involves knitting such a garment by means of a double-cylinder circular knitting machine. The machine produces a first tubular fabric suitable for covering the pelvis region using both the cylinders, which are rotated with a reciprocating motion and work with the same yarns of one or more feeds, the needles of one cylinder producing a first half of the tubular fabric when the cylinders rotate in one direction, and the needles of the other cylinder producing the other half when the cylinders rotate in the opposite direction. The machine then begins to rotate with a continuous motion, simultaneously producing with both the cylinders another two tubular fabrics, one on each cylinder, destined to cover the legs (and hereinafter called "leg portions"), each of which is knitted as a continuation of a respective half of the first tubular fabric.

While, at first sight, the appearance of such a garment is entirely acceptable thanks to the lack of any seams in the pants, it nonetheless has several fundamental drawbacks that have prevented its commercial diffusion and that are summarized below.

In the production of the pants part with a reciprocating motion, the two facing cylinders of the machine were kept as closely juxtaposed to one another as possible in order to reduce to a minimum the link between stitches needed to connect the two halves of the first tubular fabric. As a consequence, to enable the movement of the needles on each cylinder to take up the yarn and form the stitch in one or more feeds without interfering with the corresponding needles on the other cylinder, only alternate needles were used in both the cylinders, e.g. the needles in the odd-numbered positions in the lower cylinder and the needles in the even-numbered positions in the upper cylinder. The pants part was therefore produced using half of the needles available in each cylinder, obtaining a density of the knitted fabric that was less than half that of an equivalent garment classically knitted on a machine of corresponding fineness, and this severely limited the wearability and covering capacity of the garment thus obtained, particularly for the larger sizes.

Said three tubular fabrics had one point in common, the point that came to be in the lowest part of the crotch (precisely point 21 in Fig. 3 of the US patent 4011738), which is the part coming under the greatest strain. This is inevitably the point where all the tensions induced by wearing the garment become concentrated, making the garment fragile and uncomfortable to wear.

Summary of the invention

The object of the present invention is a method for knitting a garment with a body portion and two leg portions, such as pants, pantyhose or the like, of the type described in US 4011738, but substantially improved so as to substantially overcome the above-mentioned drawbacks.

Basically, in the method according to the invention, the body portion is knitted by both the cylinders with a reciprocating motion using a less than 360° arc of adjacent needles, i.e. less than the total number of needles in the cylinder. The cylinders subsequently knit the two fabrics forming the leg portions of the pantyhose in a continuous motion, using all their needles.

According to the present invention, for the knitting with a reciprocating motion of the body portion, all the needles in the two cylinders that are included in said working arc are kept active and produce stitches, those of one cylinder working when the pair of cylinders turns in one direction and those of the other cylinder working when the pair of cylinders turns in the opposite direction. The cylinders are kept at a predetermined axial distance from one another (e.g. 10 mm) sufficient to ensure that the needles working in one cylinder do not interfere with those in the opposite cylinder when, as in this case, the active feeds in one cylinder are angularly offset in relation to those in the other cylinder. This means that, when the movement is reversed, the yarn passes from the needles in one cylinder to those in the other cylinder, a corresponding stretch of yarn (that is the same length as the distance separating the cylinders) connecting the respective ends of the courses of the right and left parts of the body portion. Thus, in the finished garment, these parts of the body portion are connected by said stretches of yarn, each of which forms a link between stitches that is longer than the adjacent knitted stitches, forming two connection lines between said parts in the finished garment. When the garment is worn, these lines come to coincide with the midlines of the abdomen and the rear of the pelvis, respectively, like the seams of classic pantyhose, but in this case they have no added thickness and they have a distinctly more attractive aesthetic effect, partly because, when the garment is worn, the length of these linking stitches is partially absorbed by the adjacent columns of stitches on either side and consequently becomes scarcely visible.

One advantageous embodiment involves a knitting method comprising the following steps:

- knitting at least a part of the body portion with a reciprocating motion of the first cylinder and of the second cylinder;

- knitting the leg portions with a continuous rotating motion of the first cylinder and of the second cylinder, each cylinder knitting one of the leg portions;

wherein the needles of a temporarily inactive arc of needles are kept inactive in said first cylinder and in said second cylinder during the knitting with a reciprocating motion of said at least a part of the body portion; at least some of the needles of said two arcs of temporarily inactive needles in the first cylinder and in the second cylinder are then activated at the end of the step for knitting at least a part of said body portion with a reciprocating motion, so as to form an interknitted line joining said two leg portions; wherein at least a partial starting course of one of said leg portions is knitted by one of said first and second cylinders with float stitches that are knitted together with at least a partial starting course of the other of said leg portions, knitted by the respective arc of temporarily inactive needles in the other of said first and second cylinders, so as to connect the first leg portion and the second leg portion together along a crotch line.

In an advantageous embodiment of the invention, the method involves extracting some of the needles from the arc of temporarily inactive needles in one of said first and second cylinders (e.g. the lower one) to retain float stitches formed by the other of said first and second cylinders (e.g. the upper one) along the crotch line during the knitting of a first part of the first leg portion.

Improved embodiments of the invention advantageously include axially offsetting the two cylinders one with respect to the other in a step during which the float stitches formed by one cylinder (e.g. the upper cylinder) are knitted together with a partial starting course formed by the other of the two cylinders (e.g. the lower one).

In some embodiments of the method according to the invention, some of the needles are extracted from the arc of temporarily inactive needles in one of said two cylinders, while a first part of the first leg portion is being knitted with a continuous motion with the other of the two cylinders, keeping the needles of the latter corresponding to (i.e. opposite) the needles extracted in the other cylinder inactive.

The needles may be extracted alternately, where the term 'alternately' is used to mean a selection criterion that is not necessarily 1:1, but also 1:2 for instance, or 2:1 or 3:1, 3:2, etc., i.e. generally following a criterion according to which needles separated by a regular pitch are extracted, while the other needles remain inactive inside their respective cylinder.

In some embodiments of the method according to the present invention, when the knitting of said at least one part of the body portion has been completed using a reciprocating motion of the first and second cylinders, keeping inactive the needles in two arcs of temporarily inactive needles in both cylinders, courses of stitches comprising fabric starting courses are knitted on said first and second cylinders along a line corresponding to said arc of temporarily inactive needles in the first and second cylinders. After knitting the fabric starting courses, the knitting of the first leg portion begins with a continuous motion on one of the cylinders, forming float stitches along the arc (C) of temporarily inactive needles in said cylinder, said float stitches being retained by needles extracted along the arc of temporarily inactive needles in the other cylinder. The knitting of the first leg portion continues until the length of leg portion formed suffices to distance the two cylinders from one another by a sufficient degree to enable the simultaneous knitting in a continuous motion of said first leg portion on one cylinder and of said second leg portion on the other cylinder.

Basically, according to the invention, the two leg portions are joined along the crotch line by knitting two partial fabric starting courses, one on each cylinder, in line with the arcs of needles (opposite one another) that remained inactive during the previous fabric knitting step. After completing this step, for a sufficient number of machine rotations only one of the two leg portions is knitted with a continuous motion on one of the two cylinders, preferably the upper one, to make the leg portion increase until a sufficient length of fabric has been obtained to enable the two cylinders to be axially separated and thus enable the simultaneous parallel knitting of the two leg portions, one on one cylinder and the other on the other cylinder. During the initial phase in which the first leg portion is knitted on a first cylinder, the second cylinder remains inactive, i.e. it forms no stitches, but some of the needles (preferably needles selected 1:1) in the arc of needles remaining inactive during the knitting of the body portion are used to retain the stitches, i.e. the float stitches, formed by the cylinder that is knitting the first part of the first leg portion in line with the arc of needles previously kept inactive during the step for knitting the body portion. Retaining the stitches, or float stitches, formed by one cylinder on the needles of the other cylinder in this way enables the two leg portions to be connected along the crotch line.

In the previous step for knitting the body portion with a reciprocating motion of the two cylinders, the distance between the stitch forming planes of the two cylinders can be kept very small, because the needles in the cylinders work alternately, i.e. the needles in one cylinder work during the rotation in one direction and the needles in the other cylinder work during the rotation in the opposite direction, so the distance between the stitch forming planes can be limited to the distance needed to enable only one of the circular needle beds to work, with the upper bed completing a rotation first, and the lower bed turning in the opposite direction afterwards.

The movement for axially offsetting the two cylinders, involved in some preferred embodiments of the invention, enables alternate needles extracted from the cylinder temporarily not working to be used for a sufficient number of machine rotations, while the other cylinder knits the initial part of the first leg portion in a continuous motion, keeping the float stitches engaged without having to pull the fabric being formed, i.e. keeping the needles in the cylinder, which is temporarily not knitting, extracted. The angular offsetting by at least one needle pitch between the two cylinders enables a double set of float stitches to be formed, thereby engaging all the columns of stitches being formed on the cylinder (e.g. the upper cylinder), which starts to knit the first leg portion, to corresponding needles extracted on the other cylinder (e.g. the lower one).

According to advantageous embodiments of the invention, the method used to produce the connection between the leg portions along the crotch line involves the following set of steps:

- activating the needles in the arc of temporarily inactive needles in the second cylinder to produce fabric starting courses with said needles in the arc of temporarily inactive needles;

- reversing the direction of rotation of the first and second cylinders and activating the needles of the arc of temporarily inactive needles in the first cylinder to knit fabric starting courses;

- extracting some of the needles of the arc of temporarily inactive needles in the second cylinder while all the needles in the first cylinder are activated except for those aligned . with the needles extracted in the second cylinder, the needles activated in the arc of temporarily inactive needles in the first cylinder coming in between the needles extracted from the second cylinder and said needles activated in the second cylinder taking up and retaining float stitches produced by the first cylinder;

- while keeping said needles of the arc of temporarily inactive needles in the second cylinder extracted, axially offsetting said first cylinder and said second cylinder one with respect to the other;

- continuing to knit said first leg portion with the first cylinder to form a first piece of fabric for the first leg portion, while keeping said needles of the arc of temporarily inactive needles in the second cylinder extracted;

- restoring said first and second cylinders to a position coaxial to one another and distancing the first and second cylinders from one another parallel to the respective axes;

- starting to knit a second leg portion with the second cylinder, while the first cylinder continues to knit the first leg portion.

In some embodiments, the method according to the invention comprises an intermediate knitting step, called the "binding step" in the description that follows, coming between manufacturing the body portion with a reciprocating motion and the leg portions with a continuous motion, wherein the needles in the two cylinders that had been excluded during the production of the body portion (hereinafter called the "needles of the arc C") return to work to knit the internal parts of the two leg portions, the initial courses of the two parts being connected together to make the fabric continuous in the groin part of the garment.

During said binding step, all the needles in the two cylinders should produce fabric while the cylinders are kept at said axial distance from one another, and an initial course common to the two leg portions produced by the needles of the arc C in both cylinders to join the leg portions together at the groin would consist of stitches at least as long as said distance, with an acceptable aesthetic and covering effect.

The object of the present invention is therefore to join without any discontinuity the initial edges of said internal parts of the leg portions, while leaving the cylinders at said axial distance from one another.

In some embodiments, the binding step according to the present invention is completed while the cylinders are axially distanced from one another by a predetermined distance between the loop transfer planes of their respective sinkers, said distance being sufficient to enable the movement of the needles in each cylinder without interfering with the other cylinder. The binding step may comprise the following sub- steps:

a) while at least the last course of stitches is being completed with a reciprocating motion for the body portion and the subsequent first course of stitches is being completed with a continuous motion for the leg portions, the needles of the arc C in both the cylinders are activated after the latches have been opened by means of needle- opening devices;

b) at least a first course of a first leg portion is knitted with at least one feed in a first cylinder, while the needles of the other cylinder, throughout this and the next sub- steps, are kept inactive with their latch hooks on a level with their respective sinkers, except for a few needles of the arc C, which are kept with their latch hooks on a level in the vicinity of the stitch forming plane of the sinkers in the opposite cylinder, so as to take up and retain float stitches of at least one of the initial courses of the first leg portion; c) then the two cylinders are offset one with respect to the other, separating their axes by a distance such that, in front of said at least one feed producing the first leg portion, said needles of the arc C in the other cylinder that have taken up float stitches come to be withdrawn with respect to said feed so that they no longer take up the yarn producing the first leg portion while they continue to retain said float stitches;

d) knitting continues only on said first leg portion until the fabric produced has reached a length at least sufficient to bring said needles of the arc C that have taken up said float stitches with their latch hooks on a level with the loop transfer plane of their sinkers, thereby juxtaposing said float stitches knitted by the first cylinder with the loop transfer plane of the sinkers in the other cylinder;

e) the two cylinders are returned to a mutually coaxial position and distanced from one another so that, while the knitting of the first leg portion continues on one cylinder, the knitting of the second leg portion begins on the other cylinder.

The two leg portions are thus joined together at the groin by means of said float stitches of one leg portion being knitted together with initial courses of the other leg portion in order to join them together with a continuous knitting density despite the cylinders always being kept axially separated from one another.

After completing the binding step, the two leg portions are knitted and the cylinder that began knitting its leg portion later is left to continue after the first leg portion has been completed in order to reach the same number of knitting courses.

Thus, all the needles in both cylinders that come within said first arc of adjacent needles can be used to knit the first tubular fabric with a reciprocating motion. To knit the body portion, each cylinder can use an arc of needles amounting to 270°, for instance, obtaining a knitting density that is very similar to that of a pantyhose produced in the conventional way, knitted on a machine of the same fineness, while - as described above - the leg portions of the pantyhose will be joined together along a joining line that extends over a 90° arc of needles along the crotch line. The garment, such as pantyhose, according to this embodiment of the invention, is therefore more comfortable to wear than the known pantyhose and has no discontinuity in the density of the stitches in the fabric at the groin.

In a preferred embodiment of the invention, after at least a first course of stitches for the first leg portion has been completed with a first cylinder during the binding sub- step (b), taking up the float stitches with needles of the arc C in the other cylinder, said first cylinder is angularly offset by one needle pitch in relation to the other cylinder and at least a further initial course of the first leg portion is knitted, continuing to take up the float stitches with said needles of the arc C in the other cylinder, thereby producing a double initial course joining the two leg portions at the groin, which makes said connection stronger.

In another aspect, the invention concerns a double-cylinder circular knitting machine for manufacturing garments such as pants, pantyhose or the like. Double- cylinder circular knitting machines are in themselves known to those skilled in the art and do not require any particular description herein. They generally comprise a lower cylinder and an upper cylinder, coaxial to one another and arranged with the sliding channels for the needles overlapping one another. Double-cylinder machines usually have needles with a double latch-hook that are transferred alternately in one or the other of the two cylinders. In some double-cylinder circular machines, there are two sets of needles, one in the upper cylinder and the other in the lower cylinder. Typically, the needles in the lower and upper cylinders are aligned with one another, with the needles facing each other, i.e. the needles in the lower cylinder with their respective latch hooks upwards and the needles in the other cylinder with their latch hooks downwards, in mutually aligned positions. A machine of this type is described in US- A-4,011,738.

The invention characteristically relates to a double-cylinder machine with an upper cylinder and a lower cylinder, one above the other, and with the needles in one cylinder facing towards the needles in the other cylinder, and comprising a control system for implementing a knitting method as described above.

According to one aspect, the machine according to the invention is characterized in that it has a device that enables the needles to be axially offset, i.e. to stagger the axes of the two cylinders, arranged one above the other, while keeping them substantially parallel to each other. In some embodiments, the machine also comprises a device that enables axial displacement of the two cylinders by one of at least two predetermined distances, one for working the body portion and the binding step, and one for working the leg portions.

In a preferred embodiment of the invention, the machine also advantageously involves a device for angularly offsetting the two cylinders by at least one needle pitch during the binding step.

In the machine according to the invention, moreover, in order to reduce the knitting time as much as possible, the needles of each cylinder can be operated with up to four feeds of yarn, the feeds of each cylinder being arranged mainly at 90° angles to one another and angularly aligned with those of the other cylinder. In the various pantyhose manufacturing steps, moreover, the following can be working:

for the body portion and the binding step, two adjacent feeds of one cylinder and the opposite feeds of the other cylinder, and the two cylinders are separated from one another in a plane that is a plane of symmetry in relation to the two feeds working on each cylinder;

for the leg portions, four feeds for each cylinder.

According to one embodiment, the invention involves a knitted garment comprising a body portion and two leg portions, joined along a crotch area, wherein said body portion and said leg portions are formed of a seamless, continuous knitted fabric, wherein there is a line for joining the two leg portions in the crotch area formed by at least one partial interknitted course common to the two leg portions. The joining line (C) is formed by means of a binding step as described above, and the body portion comprises at least an upper part formed by two portions joined along two interknitted lines generated by reversing the reciprocating movement of the needle cylinders and consequently passing the yarns from one to the other of the two needle beds in the double-cylinder machine on which the garment is knitted. The two interknitted lines extend respectively over a front portion and a rear portion of the garment, and the front interknitted line is joined to the rear interknitted line by the joining courses between the two leg portions formed during said binding step, which extend along the lower part of the body portion. In practice, the two interknitted lines and the joining line at the crotch extend along a curve extending from the front central area of the edge of the garment to the rear central area of the edge of the garment, passing through the groin area, i.e. between the two leg portions.

Further advantageous features and embodiments of the method, the machine and the garment according to the invention are described below in relation to an example of an embodiment and in the attached claims, which form an integral part of the present description.

Brief description of the drawings

The invention will be better understood from the following description and the attached drawing, which shows a non-limiting practical embodiment of the invention. More in particular, in the drawings:

Fig. 1 shows a schematic prospective view of pantyhose according to the invention;

Figs. 2 and 3 show a schematic prospective partial view of the two cylinders of a circular machine in two stages of the knitting of the pantyhose in Fig. 1, respectively during the knitting of the pants and during the knitting of the leg portions;

Fig. 4 shows a prospective side view of the pantyhose manufactured in Figs. 2 and 3, as they appear when they drop from the machine;

Fig. 5 is a cross-sectional view along V-V of the pantyhose in Fig. 4;

Figs. 6A-6D show respective views of a double-cylinder circular knitting machine according to the invention in a cross-section along an axial plane that dissects the arc of needles remaining inactive during respective steps in the knitting of the pantyhose;

Fig. 7 shows an enlarged view of the needles along the arc of temporarily inactive needles during the binding step;

Fig. 8 schematically shows an enlarged detail of the binding area along the crotch line in a simplified embodiment;

Fig. 8A shows a similar detail to the one in Fig. 8, in a non-simplified embodiment;

Fig. 9 shows an enlargement of detail ΓΧ in Fig. 6B;

Fig. 10 shows an enlargement of detail X in Fig. 6C;

Fig. 11 shows a front view of the knitting head of a double-cylinder circular knitting machine suitable for manufacturing pantyhose according to the method of the invention;

Fig. 12 shows a similar view to the one in Fig. 11, but with the upper cylinder and its supporting and control members further raised in relation to the lower cylinder and the remainder of the machine;

Fig. 13 is a plan view along ΧΠΙ-ΧΠΙ of Fig. 11 ;

Figs. 14 and 15 are views respectively from above along XTV-XTV of Fig. 11 and from below along XV-XV of Fig. 11 ;

Figs. 16 and 17 are side views of the knitting head along XVI-XVI of Fig. 11 in two different cylinder alignment conditions;

Figs. 18 and 19 are enlarged views respectively along XVIII-XVIII and ΧΓΧ-ΧΓΧ of Fig. 17;

Fig. 20 is a prospective view in the direction of the arrow Fl of Fig. 18;

Fig. 21 is a view along XXI-XXI of Fig. 20; and

Figs. 22 to 33 show views of the needles, sub-needles and sinkers in the two heads (shown tipped along the plane of the drawing), the yarn-guide outlets of the feeds active in the step illustrated in each figure, and the needle and sub-needle raising cams of the machine in Fig. 11, seen from outside the cylinders and developed on a plane.

Detailed description of embodiments of the invention

Fig. 11 shows a front view of the knitting head of a double-cylinder circular knitting machine designed to produce pantyhose according to the method of the invention and comprising two heads, positioned one above the other, with four feeds each. Each head comprises a cylinder and respective knitting and yarn feeding members. In the example illustrated, in particular, the machine comprises a lower cylinder 11 and an upper cylinder 13. The cylinders 11, 13 of the two heads are generally coaxial (except during certain so-called "binding" steps, during which they are slightly and temporarily axially offset, as explained later on) and they have ends fitted with needles facing each other in a mirror arrangement in relation to a horizontal plane through Y-Y, and needle channels aligned with one another. Each cylinder is fitted with channels in which respective needles slide, identified by the numeral 15 for both the upper cylinder (13), and the lower cylinder (11).

The lower cylinder 11 is supported by bearings 12A (Fig. 17) inside a supporting member 12 attached to a base plate 14, which is in turn supported by a machine base (not shown in the drawing). The needle and sub-needle raising cams in the lower cylinder 11 are fixed to the supporting member 12 by means of an intermediate ring- shaped plate 16 supported by columns 18, while yarn guides 24 (Fig. 14) are hinged in line with respective vertical axes 24A to an upper ring-shaped plate 20 - supported on the intermediate plate 16 by means of columns 22, the yarn guides being individually operated by means of respective pneumatic actuators 24B and solenoid valves (not shown in the drawing). Fig. 14 also shows the so-called "sinker housing" 26, i.e. - as is common knowledge to a person skilled in the art - a ring-shaped plate that carries the ring of cams for controlling the sinkers on its underside and that is held centered on a sinker cam ring integral with the cylinder 11 (not shown in the drawing) by means of three pins 28 fitted with ball bearings. Attached to the sinker housing 26 there are the yarn-guide outlets 30A, 30B of the four feeds for the lower head, two yarn-guide outlets 3 OB being fixed to the housing itself by means of screws, and two yarn-guide outlets 30A being mounted radially slidingly on the housing by means of respective slides 30C driven by respective actuators (not shown) designed to keep them either in the radial position juxtaposed with the cylinder 11, as shown in Fig. 14, or in a position radially further away from the latter, depending on the pantyhose manufacturing method according to the invention, as explained later on.

Attached to the base plate 14 there are three vertical columns 30, 32, 34 (see also Fig. 16) which, by means of respective sliding sleeves 30A, 32A, 34A integral with a plate 23, support said plate 23, to which the upper head of the machine is attached. Similarly to the description of the lower cylinder 11, the upper head comprises a supporting member 36 that, by means of bearings 36 A (Fig. 17), supports the upper needle cylinder 13. Attached to the supporting member 36, by means of an intermediate ring-shaped plate 38 underneath said supporting member, and supported by columns 40, there are the needle and sub-needle raising cams of the upper cylinder 13, while yarn- guides 46 (Fig. 15) are hinged about respective vertical axes 46A to a further ring- shaped plate 42, underneath said intermediate plate 38 and supported thereby on columns 44, said yarn guides being operated individually by means of respective pneumatic actuators 46B and solenoid valves (not shown in the drawing). As in the above description of the lower cylinder, Fig. 15 also shows the "sinker housing" 48 of the upper cylinder 13, which is kept centered on the sinker cam ring of the upper cylinder 13 (not shown in the drawing) by means of three pins fitted with ball bearings. The yarn-guide outlets 50A, 50B for the four feeds of the upper head are applied to the sinker housing 48, two yarn-guide outlets 50B being fixed to the housing itself by means of screws, and two yarn-guide outlets 50 A being arranged radially slidingly on the housing by means of respective slides 50C operated by means of respective actuators (not shown) designed to keep them either in the radial position juxtaposed with the cylinder 13, as shown in Fig. 15, or in a position radially further away from the cylinder, depending on the pantyhose manufacturing procedure according to the invention, as explained later on.

The plate 23 that supports the upper head can be moved vertically along the three vertical columns 30, 32, 34 (see also Fig. 12) by means of said sliding sleeves 30A, 32A, 34A under the action of a pair of jacks 52, 54 coaxial to one another and attached to the plates 14, 23, respectively. Said jacks are arranged so that the stems 52A, 54A of their corresponding pistons are coaxial, the ends of said stems being opposite one another with a spacer 55 inserted between them. The spacer 55 is screwed onto the free end of the stem 52A by means of a threaded hole it contains and fixed thereon by means of a nut 57.

Thus, when neither of the two jacks 52, 54 is enabled, the vertical distance between the two heads of the machine, and particularly the vertical distance of the loop transfer planes from the sinkers, in the arrangement shown in Fig. 11 can be adjusted by means of the stems of the two jacks and the threaded spacer 55. Said distance is set at a value Zl (see Fig. 6B) that it is slightly greater than the distance "d" (Fig. 9) between the distal end of the needle - on the latch-hook side - and the tip of its completely open latch (e.g. Zl=10 mm if this distance in the needle is 9 mm), so as to enable the two heads lying one above the other to knit simultaneously with angularly mutually staggered feeds.

In addition, the stroke of the first jack 52 is preset to raise the upper head to the arrangement shown in Fig. 12, distancing the two cylinders 11, 13 from one another so as to bring the distance between the loop transfer planes of the sinkers to a second value Z2, corresponding to at least twice the value Zl. Finally, when the second jack 54 is operated, it enables the further distancing of the two heads of the machine to facilitate the routine servicing of the machine, e.g. for inserting the yarns in the yarn guides, changing needles, and so on.

The machine according to the invention also has a device for axially offsetting the two cylinders by a distance Yl (Fig. 17) (e.g. around 4.5 mm) during certain binding steps, as described later on. The device comprises a pair of parallel guides 58 (Figs. 11, 16 and 17) attached to the upper surface of the plate 23, on which slides 58A fixed to a plate 56 supporting the upper cylinder-holder 36 can slide. These guides are oriented perpendicular to the plane of the drawing in Fig. 11 and a pair of pneumatic jacks 60 with their axes parallel to the guides - connected to the pins 56A, 23A attached to the plates 56, 23, respectively - is inserted between said plates 23, 56 in order to displace them at will along the guides 58 by said predetermined distance Yl, thereby offsetting the relative axes of the two machine heads, and of the cylinders 11, 13 in particular. Adjustable end-of-stroke stops (not shown in the drawing) enable said distance Yl to be adjusted to the required value. To enable said axial offsetting when the cylinders are in operation, the transmission of the movement between the cylinders 11 and 13 comprises a coupling shaft 62 (see also Figs. 16 and 17) the ends of which are each connected by means of respective bellows-type flexible couplings 64 to respective toothed pulleys 66, 68, the upper flexible coupling 64 being connected to the shaft 62 by means of a splined joint 65. A respective toothed belt 70, 72 connects each toothed pulley 68, 66 to a corresponding toothed pulley 74, 76 torsionally integral with the respective cylinder 13, 11. The bellows-type flexible couplings 64 and the splined joint 65 enable a limited axial offsetting of the cylinders 11, 13 over the distance Yl without introducing any slack in the transmission.

The machine according to the invention also has a device for angularly offsetting the cylinders, designed to offset them one with respect to the other by a predetermined angular value, corresponding to one needle pitch for instance, during certain steps in the knitting process, as explained later on. This device comprises a pair of belt-tensioning rollers 78 (Figs. 18 to 21 A) designed to keep the upper belt 70 of the transmission between the cylinders 11 and 13 taut. Each roller 78 turns idly on a respective pin 80 integral with a respective link rod 82 attached to a plate 84 by means of a threaded pin 82A. The plate 84 is kept juxtaposed - by means of hexagon-head pins 85 - with the underside of a supporting plate 86 integral with the plate 56, and can slide in relation thereto orthogonally to the plane of the axes of the two cylinders 11, 13 along two slots 84A thereof, through which the pins 85 pass with a minimum lack. The pins 80 are connected together by means of a tie rod 88 (Figs. 18, 20, 21 A), the ends of which are threaded and fixed with the aid of nuts 88 A to small blocks 80 A integral with the pins 80, so as to enable an adjustment at will of the tension on the toothed belt 70 after temporarily loosening the screws 82A for locking the link rods 82 carrying the belt- tensioning rollers, to enable the rotation of said link rods in relation to the plate 84. An additional plate 90 is kept closely juxtaposed with the upper side of the plate 86 by means of hexagon-head pins 90 A, and a pneumatic jack 92 is fixed to said plate 90, with its stem 92A fixed to a bracket 94 integral with the plate 56. The plate 90 can slide in relation to the supporting plate 86 parallel to a plane P-P (Figs. 13, 18, 19) on which the axes of the cylinders 11, 13 lie when they are axially offset. This sliding movement is defined by slots 90B in which the pins 90A pass with a minimal slack. The plate 90 also has two parallel opposite edges 90C inclined with respect to the plane P-P, against which two idle rollers 96 rest without any slack (Figs. 18, 21), their axles being integral with the plate 86. By operating the jack 92, it is therefore possible displace the plate 90 with the two belt-tensioning rollers 78 by a predetermined amount orthogonally to the plane P-P. By means of said movement, the belt-tensioning rollers 78 induce/enable the elongation/release (depending on the direction of said displacement) of the respective stretches of belt with which they are each in contact, thereby inducing a relative rotation of the two pulleys 68, 74 and a consequent angular offsetting of the cylinders 11, 13 one with respect to the other.

Figs. 22 to 33 show various moments in the knitting cycle represented with the two cylinders 11 and 13 developed along a plane, and limited to the members fundamental to understanding the knitting process. In the various figures, the same numerals and symbols indicate the same parts of the machine in the various arrangements. More in particular, Figs. 22 to 33 show:

four yarn-guide outlets 30A, 30B, 30B, 30A corresponding to the four feeds of the lower cylinder 11, and four yarn-guide outlets 50A, 50B, 50B, 50A corresponding to the four feeds of the upper cylinder 13. It should be noted that in these figures, the outlets for the lower cylinder and the outlets for the upper cylinder, like the stitch-forming cams (and therefore ultimately the feeds of the two cylinders) are in approximately corresponding angular positions. This situation is not strictly binding, however, since the feeds of one cylinder can be angularly offset with respect to the feeds of the other cylinder;

the needle raising cams 15 (or stitch cams) 100 A, 100B, lOOC, 100D, of the upper cylinder 13 and the corresponding needle raising cams 200 A, 200B, 200C, 200D of the lower cylinder 11. These cams can generally be moved radially to enable them to be excluded from the working process in certain steps of the pantyhose knitting process. For a better understanding of how the machine operates, and particularly of the binding step along the crotch line, between the two leg portions, Figs. 22 to 33 show those the stitch cams which are excluded from the process with dotted lines. These cams do not interfere with the butts of the needles and consequently do not have any effect on the needles when the latter pass with their butts in front of the cams;

cams 102 A, 102B for guiding the sub-needles S in the upper cylinder 13 and the similar cams 202A, 202B in the lower cylinder 11 ;

sets of levers 104A, 104B, 104C, 104D for controlling the sub-needles S in the upper cylinder 13 and similar sets 202 A, 204B, 204C, 204D in the lower cylinder 11;

yarn-guide outlets 5 OA, 50B of the upper head and corresponding outlets 3 OA, 30B of the lower head. The outlets 50A, 30A, which are radially extractable, are shown with a dotted line in the steps during in which they are extracted.

Moreover, a needle 15, with the corresponding sub-needle S, and sinker P, are shown for each cylinder (tipped onto the plane of the drawing) on the left-hand side of the figures in question. The various components are arranged in line with the respective levels in the position in which the needles form stitches.

Figs. 22 to 33 also show in dotted lines the paths of the ends of the needles during various steps during knitting of the pantyhose. In line with the cylinder feeds, the trajectories of the needle latch-hooks along the rising and falling trajectory defined by the stitch forming cams are shown. Below, the term "raising" of the needles normally refers to the movement for extracting the needle from the cylinder, irrespective of the orientation in space of said movement. Thus, the downward movement for extracting needles in the upper cylinder in the direction of the lower cylinder may be indicated as a "raising" movement (as is normally the case in the technical jargon used in the knitting industry). Likewise, the term "lowering" is used generically to indicate the movement for retracting the needles inside their respective cylinders.

As explained later on, in some steps in the knitting process not all the needles of a given arc of needles are activated; rather only some suitably selected needles are activated, , e.g. according to a 1:1 selection, or also according to other selection patterns, e.g. 1:2 or 1:3. In the schematic representation of Figs. 22 to 33, this selection is indicated by means of a set of vertical lines coinciding with the upward or downward curve of the needles. In Fig. 24, for instance, all the needles are raised in line with the feed 3 OB on the left (when looking at the drawing), while in the feed 3 OB on the right only the even-numbered needles, or only the odd-numbered needles or, more in general, only some of the needles are raised, depending on the selection pattern adopted. This circumstance is represented by the vertical lines superimposed on the profile of the curve of the needles in line with the outlet of the feed 3 OB on the right-hand side.

Fig. 1 shows a schematic partial perspective view of pantyhose obtainable with the machine and the method according to the invention. Fig. 1 shows several elements that are important for understanding the pantyhose knitting method.

In particular, the pantyhose in Fig. 1 can be divided into a body portion 1 that comprises an elastic edge 3A, 3B surrounding the opening for putting on the garment (pantyhose), and an area 5A, 5B suitable for covering the pelvis, and leg portions 9A 9B for covering the legs. The body portion 3A, 5A; 3B, 5B is knitted with a reciprocating motion in the above-described double-cylinder circular knitting machine according to the invention, the left half 5 A of the body portion (looking at Fig. 1) being knitted on the upper cylinder 13 while it rotates in one direction, and the right half 5B on the lower cylinder 11 while it rotates in the opposite direction, said halves being joined along two ideal midlines (m, n) respectively on the front and on the back of the pantyhose.

During the knitting of the body portion, the two cylinders 11, 13 of the machine are separated from one another by a distance Zl between the loop transfer planes of the respective sinkers P (Fig. 6 A) and the needle raising cams 100 A, 100D of the upper cylinder 13 and 200 A, 200B of the lower cylinder 11 are excluded from the working process. During this knitting step, when the cylinders rotate in the direction of the arrow F2 (Fig. 22), the upper head works with two feeds of yarn coinciding with the yarn- guide outlets 50B (see also Fig. 15, the various feeds of the two heads being indicated here and later on with reference to their respective yarn-guide outlets) while the needles in the lower head are inactive and they all pass with their free ends on a level with the loop transfer plane of the respective sinkers. This is clearly shown in Fig. 22 by the upward and downward curve (i.e. of extraction and retraction) of the needles 15 in the upper cylinder 13 in line with the feeds 50B, 50B, and by the straight dotted line representing the absence of movement for the needles 15 of the lower cylinder 11.

When the cylinders rotate in the opposite direction F3 (Fig. 23), it is the lower head that works with two feeds of yarn coinciding with the yarn-guide outlets 30B (see also Fig. 15), while the needles of the upper head are inactive and they all pass with their free ends on a level with the loop transfer plane of their respective sinkers. Thus, with each change in the direction of the rotational movement, the yarn on each feed passes from the needles of one cylinder to those of the other, producing the two lines of interknitted stitches m, n that join the two parts 3 A, 5 A and 3B, 5B of the body portion.

Conversely, the leg portions 9A, 9B are knitted using a continuous motion with all four feeds of the two heads corresponding to the outlets 30A, 30B; 50A, 50B in Figs. 14, 15, and 33. The left leg portion 9 A is knitted on the upper cylinder 13 of the machine and the right leg portion 9B is knitted on the lower cylinder 11. Two dotted lines Al, A2 in Fig. 1 indicate the courses of stitches passing between the part 5 A, 5B of the body portion 1 knitted with a reciprocating motion and the leg portions 9A, 9B knitted with a continuous motion.

The leg portions 9A, 9B are joined together along a partial arc CC of stitches that defines the crotch line of the pantyhose, the ends CI, C2 of said line coinciding with the points joining the lines Al and A2 and m, n. The crotch line CC is formed of one or more initial partial courses of stitches knitted by each cylinder, the courses being interlinked or knitted together as described below with reference to the so-called "binding step" in the pantyhose knitting procedure.

In Fig. 1 continuous lines show the development of the columns of stitches formed by single needles. As shown in this figure, the columns extend from the elastic edge 3 A, 3B along the part 5 A, 5B of the body portion 1, forming a single tubular fabric and are subsequently divided to form the two leg portions 9A, 9B, except for the columns of stitches that form the internal area of the leg portions 9A, 9B and that start from said line CC.

According to the invention, not all the needles of the cylinders 11 and 13 are activated during knitting of the body portion. In fact, an arc of adjacent needles in each cylinder is used that corresponds to a majority of the total number of needles, e.g. 350 needles in a cylinder containing 400 needles are used to form an arc of adjacent active needles. The remaining needles form an arc C of inactive needles. This arc C of needles will hereinafter also be called the "arc of temporarily inactive needles". This applies to both the cylinder 11 and the cylinder 13. The needles in the arc C of each of the two cylinders are substantially in the same angular position, i.e. they face one another. They are inactive in the sense that during the knitting of the body portion they always remain excluded from the working process, i.e. retracted inside the channels of their respective cylinder, both when the cylinders rotate clockwise and when they rotate anticlockwise. Vice versa, as explained previously, the other needles forming the arc complementary to the arc C of inactive needles work alternately, first those on one cylinder when it rotates clockwise, then those on the other cylinder when it rotates anticlockwise.

There is consequently a substantial difference vis-a-vis the knitting procedures described in previous patents mentioned in the introductory part of the present description, wherein, all the needles in both the upper cylinder and the lower cylinder are activated alternately during the knitting step, first on one cylinder when the machine turns clockwise, then on the other when it turns anticlockwise. In practice, the knitting of the edge 3 A, 3B and of the part 5 A, 5B of the body portion 1 can be done, according to the invention, using a majority of the needles in each cylinder, e.g. 350 needles in a cylinder containing 400 needles. The total number of columns of stitches for the elastic edge 3A, 3B and the part 5A, 5B of the body portion thus amounts to 700. From now on, N5 indicates the number of stitches in the part 5A, 5B of the body portion, while Nc/2 indicates the number of needles remaining inactive during this step in which the knitting is done with a reciprocating motion.

After completing the knitting, with a reciprocating motion, of the two halves 5A, 5B of part of the body portion 1 with respective partial terminal courses Al, A2, after a step designed to begin knitting on the arc C of needles that had previously remained inactive (the so-called binding step, described in more detail later on), knitting the leg portions 9A, 9B begins (see Fig. 3). The leg portion knitting step is completed with the two cylinders 11, 13 turning with a continuous motion in the same direction, each knitting yarns from their respective feeds and each producing a respective leg portion 9A, 9B with all the needles in the cylinder (e.g. 400), i.e. also activating the needles of the two cylinders 11, 13 that had previously remained inactive along the arc C in a number corresponding to Nc/2 (= 50 in this example). Each leg portion will therefore have a number of columns of stitches N9, amounting to the number of needles in the cylinder (400 needles in the present example).

Advantageously, during the knitting process, inside the upper cylinder 13 a current of air is generated from above by means of a traditional suction system not shown in the drawing. Thus, as the pantyhose is knitted (Figs. 2 and 3), it is sucked upwards and moves through the inside of the upper cylinder 13 with the parts 3B of the edge and 5B of the body portion and the leg portion 9B inserted inside the corresponding parts 3A, 5A, 9A of the pantyhose, so that, when the pantyhose is removed from the machine, it appears as shown in Figs. 4 and 5. To make the pantyhose suitable for wearing, as shown in Fig. 1, the right leg portion 9B (as you look at Fig. 1) has to be withdrawn from inside the left leg portion 9A by taking action in the direction of the arrow F in Fig. 5, and thereby also extracting the right portion 5B of the body portion and 3B of the elastic edge when this reversal of the leg portion 9B is complete.

The binding step in the pantyhose knitting procedure will now described.

When the body portion has been completed, it appears as shown in Fig. 6A, with the terminal courses Al, A2 of the body portion held by the needles of the two cylinders 11, 13 on their respective arcs complementary to the arc C, and the needles on the arc C of both the cylinders have no stitches because they have so far remained inactive.

At this point, before starting to knit the leg portions 9A, 9B with a continuous motion, the binding step isperformed, wherein the needles of the arc C of temporarily inactive needles on each cylinder 11, 13 are reactivated to knit the part of the two leg portions inside the crotch line CC, the initial courses of the two parts being connected together along the line CC in the manner described below to ensure continuity to the fabric of the garment at the groin.

The binding step is performed while the cylinders are axially distanced from one another by a distance Zl in the same way as during the knitting of the body portion and as described below with particular reference to the sequence of Figs. 24 to 33. The binding step comprises the following sub-steps:

a) while, at the end of the body portion, the last oscillation of the reciprocating motion is completed in the direction of the arrow F3 (Fig. 24) to form the last course A2 of stitches on the body portion in the lower cylinder 11 with the feeds 30B, the needle-openers 25 in the lower head (see also Fig. 14) are activated and then the needles of the arc C of the lower cylinder that had remained inactive during knitting of the body portion are also raised (i.e. they are extracted from the cylinder) so as to produce two fabric-starting courses with said needles of the arc C in said feeds 30B in the classical manner, i.e. by working with all the needles of said arc in the first feed 30B (the one on the left looking at Fig. 24) and at least some of the needles in the second feed 30B (on the right). The needles activated in the second feed 3 OB are suitably selected. According to a currently preferred embodiment, the selection involves a 1:1 pattern, i.e. alternate needles are selected, e.g. all the odd-numbered needles are raised and all the even-numbered needles are kept inactive, or vice versa. This situation is represented schematically in Fig. 24 with a series of vertical lines overlapping the stitch formation curve of the needles along the second feed 30B (i.e. the one on the right in Fig. 24). Basically, in the final rotation all the needles of the cylinder 11 are active in line with the feed 3 OB on the left and so are all the needles except for alternate needles (that are not selected) in the arc of temporarily inactive needles (C) in the second feed 30B on the right in Fig. 24; b) after completing the final turn with a reciprocating motion, the cylinder movement is reversed to produce the first rotation in a continuous motion in the direction F2 (Fig. 25) and, while all the needles of the lower cylinder 11 are kept inactive (as shown by the fact that the cams 200A-200B, 200C, 200D are drawn with a dotted line) with their latch-hooks on a level with the corresponding sinkers, the needle-opener 47 on the upper head (see also Fig. 15) and the needles of the arc C of temporarily inactive needles on the upper cylinder 13, i.e. the needles that had remained inactive during the knitting of the body portion, are activated to produce two fabric-starting courses on said arc C in the classical manner, i.e. by activating all the needles in a first feed 50B (the one on the right looking at Fig. 25) and alternate needles (or in any case those suitably selected, as explained in reference to the selection of the needles on the arc C of the lower cylinder 11 in the step illustrated in Fig. 24) in the second feed 50B (the one on the left);

for the next row (Fig. 26), while all the needles of the upper cylinder 13 continue to knit in the two feeds 50B to produce an initial part of the leg portion 9A, certain selected needles of the arc C of temporarily inactive needles in the lower cylinder 11 are raised by means of the selection pack 204D and the cams 202B in the lower head (see Figs. 6B, 7 and 9). It should be noted that, for this step, the preferred selection is 1:1, the even-numbered needles preferably being selected and extracted from the lower cylinder 11, while the odd-numbered needles of the arc C are left inactive inside the cylinder. This hypothesis will be assumed from now on, which coincides (as clarified below) with a similar, complementary needle selection in the upper cylinder: if the even-numbered needles are activated in the lower cylinder, the odd-numbered needles will be activated in the corresponding arc C of the upper cylinder 13, and vice versa. This is on the understanding, however, that in other, less advantageous embodiments the selection may be different, e.g. the needles may be selected and extracted according to a selection pattern of 1:2 or 1:3, or 2:3, or 2:3, etc. What is important is that not all the needles in the arc C of temporarily inactive needles must be raised; some of them must remain retracted, i.e. inactive. In any case, the selected needles extracted from the cylinder 11 are brought with their latch hooks on a level with, and in the vicinity of the stitch forming plane of the sinkers P of the upper cylinder 13, where they are also kept for sub-steps d), e) described below. In Fig. 26 a curve is superimposed on the feed 3 OA, said curve representing the trajectory of the needles with a set of vertical lines: the curve shows that the needles are raised, i.e. extracted from the cylinder and kept on the level they reach by means of the needle-raising cam, since the corresponding stitch forming cam is not active. This coincides with the fact that the selected needles must remain in the extracted position in the subsequent stages (d) and (e) too for the reasons clarified below. The vertical lines superimposed on the curve illustrating the path of the needles indicates that the needles have been selected, i.e. not all the needles, but only those in the odd-numbered positions, for instance, have been extracted from the cylinder. At the same time, by means of respective selection lever packs 104C, 104D and the cams 102B in the upper head, all the needles in the upper cylinder 13 are activated (i.e. extracted) except for the needles of the arc C (Fig. 7) corresponding to the needles selected on said arc C in the lower cylinder 11. In the present example, since it has been chosen to extract the odd-numbered needles in the arc C of temporarily inactive needles in the lower cylinder 11, in the corresponding arc C of the upper cylinder the even-numbered needles will be extracted, while the odd-numbered needles remain inactive (and consequently withdrawn inside their respective channels), which are left on a level with their respective sinkers, so that when the needles in the even-numbered positions on the arc C of the upper cylinder 13 pass in front of the feeds 50B, (Figs. 27, 28), they come in between the raised odd- numbered needles of the lower cylinder 11 (Fig. 7), and the latter therefore take up and retain the float stitches of the courses produced by the upper cylinder 13, as shown in Figs. 7, 6B and 9;

then, while knitting continues with two feeds of the leg portion 9A in the upper cylinder 13, by means of the previously described device for offsetting the axes of the two cylinders in relation to one another, their axes are distanced by a distance Yl (Fig. 6C) such that, as they pass in front of said feeds 50B that are knitting courses of leg portion with the upper cylinder 13, the alternate needles (in the odd-numbered positions in the example described here) of the arc C of the lower cylinder 11, which have taken up said float stitches, are withdrawn in relation to the feeds 5 OB so that they cannot take up any more yarn, while they continue to retain said float stitches. Before implementing the above-described axial offsetting of the cylinders 11, 13, the outlets 30A and 50A (Fig. 31) belonging to feeds that are not activated during this step have to be extracted radially to avoid them interfering with the needles as a result of said axial offsetting of the cylinders;

e) after axial offsetting of the cylinders, the machine continues to knit the leg portion 9A with the upper cylinder 13 alone (Fig. 31) with the two feeds 50B until the fabric thus produced (i.e. the portion of fabric W in Fig. 6C) has reached a length Z2 - when stretched in the direction of the columns of stitches - and then, by means of the set of selection levers 204A and the cam 202A, the needles in the odd-numbered positions of the arc C of the lower cylinder 11 (i.e. the needles that have taken up the float stitches of the initial courses of the leg portion produced by the upper cylinder 13) are lowered, bringing them with their latch-hooks on a level with the loop transfer plane of their sinkers, and thereby juxtaposing the float stitches produced by the upper cylinder 13, and also the initial courses of the piece W of the leg portion 9A, with the loop transfer plane of the sinkers of the lower cylinder 11 ;

f) the two cylinders 11, 13 are restored to a coaxial position and are distanced from one another with a movement parallel to their axes until the distance Z2 is reached between the loop transfer planes of the respective sinkers, as shown in Fig. 32. This movement for mutually distancing the cylinders 11, 13 and the respective stitch forming planes is enabled by the fact that the piece W of fabric has been formed in the previous sub-steps. In addition, the outlets 30A and 50A, which had been extracted for the sub-step d), are radially repositioned near the center in their working position and while the knitting of the corresponding leg portion 9 A continues with the two feeds 50B in the upper cylinder 13, the knitting of the corresponding leg portion 9B begins in the lower cylinder 11 with the two feeds 30B (Fig. 32). Then the remaining two feeds 50A, 50A and 30A, 30A of the upper cylinder 13 and of the lower cylinder 11, respectively, are activated to complete the formation with a continuous motion of the two leg portions 9A, 9B using all eight feeds on the machine.

Following the above-described procedure, the leg portions 9 A, 9B are joined together at the groin, i.e. along the crotch line CC, with a continuity of knitting density by means of the float stitches of at least two courses of stitches, despite the fact that the cylinders have always been kept distanced from one another with an axial distance between them of at least Zl .

During the knitting of the leg portions, the lower cylinder (which began knitting its leg portion 9B later) is allowed to continue knitting after the other leg portion 9A has been finished in order to reach the same number of courses of stitches. Then the finished pantyhose is discharged from the machine.

In a preferred embodiment of the pantyhose knitting procedure, between sub-steps c) and d) in the binding step, there is an additional sub-step cl) wherein, after collecting float stitches of two courses produced by the upper cylinder 13 in step c) in the arc C - using odd-numbered needles kept raised in the lower cylinder 11 - the 1:1 selection pattern of the needles of the arc C in the upper cylinder is reversed and at the same time, with the aid of the jack 92 (Fig. 18), the device for the angular axial offsetting of the cylinders is used to offset the cylinders by one needle pitch. As a result, the odd- numbered needles of the arc C in the lower cylinder 11 take up float stitches of at least another two courses produced on the arc C by odd-numbered needles in the upper cylinder 13, passing in front of the respective feeds 50B (Figs. 29 and 30), and thereby connecting the first course of the leg portion 9B at the crotch CC not only with the float stitches on even-numbered needles corresponding to at least two initial courses of the leg portion 9A, but also with the float stitches on odd-numbered needles of another at least two subsequent courses of the leg portion 9A, thereby obtaining a reinforced, denser connection between the two leg portions at the crotch CC.

Fig. 8 is a simplified illustration of the area where the float stitches are formed. For a more straightforward representation and a better understanding of the drawing in this figure, the interknitting is shown restricted to one feed, i.e. the interknitting obtainable using only one feed 30B for the lower cylinder 11 and only one feed 50B for the upper cylinder 13. RSI and RS2 indicate the two fabric starting courses formed by the upper cylinder 13 along the crotch line CC, i.e. in line with the arc C of temporarily inactive needles. If the process is completed using two feeds, the two courses are generated with only one rotation of the machine. If only one feed is used, it will take two rotations of the machine to generate the two courses RSI, RS2, but the result is always the formation of two fabric starting courses. The same applies to the lower cylinder 11; RI1 and RI2 indicate the first two courses of stitches formed along the arc or crotch line CC.

Again with reference to Fig. 8, along the arc C of temporarily inactive needles, 15D- I indicates the raised (i.e. extracted) needles in the odd-numbered positions of the lower cylinder 11 in the binding step, while 15P-I indicates the needles in even-numbered positions in the lower cylinder that are not extracted. 15P-S indicates the activated needles in the even-numbered positions in the upper cylinder 13 and 15D-S the needles in odd-numbered positions in the upper cylinder 13 that are not activated. RF1 and RF2 indicate the float stitches formed by only one of the two feeds 5 OB in the two sub-steps (c) and (cl).

Fig. 8A shows the same interknitted area illustrated in Fig. 8, but with a double feed.

In the above description, it has been assumed that the knitting of the leg portion 9A begins on the upper cylinder 13 with a continuous rotational motion, while the lower cylinder 11 is disabled, using only alternate needles of the arc C of temporarily inactive needles in the lower cylinder 11 to retain the float stitches along the crotch line. This solution is preferred because it enables normal needles with latch-hooks to be used. In fact, the latches of the needles extracted from the lower cylinder 11 that retain the float stitches remain open due to the effect of gravity, with no need to use complicated compound needles or other complex solutions. This does not rule out the feasibility, however, of starting to knit the leg portion 9B on the cylinder 11 while the cylinder 13 is used to retain the float stitches.

Claims

1. A method for knitting a garment comprising a body portion (1) and two leg portions (9A, 9B) by means of a double-cylinder circular knitting machine comprising a first cylinder (13) fitted with needles (15) and a second cylinder (11) fitted with needles (15), said cylinders being arranged one on top of the other, comprising the following steps:

- knitting at least one part (3 A, 5 A, 3B, 5B) of the body portion (1) with a reciprocating motion of the first cylinder (13) and of the second cylinder (11);

- knitting the leg portions (9 A, 9B) with a continuous rotary motion of the first cylinder (13) and of the second cylinder (11), each cylinder knitting one of the leg portions;

characterized in that: the needles of a temporarily inactive arc (C) of needles on said first cylinder (13) and on said second cylinder (11) are kept inactive during the knitting with a reciprocating motion of said at least one part (3A, 5A, 3B, 5B) of the body portion (1); at least some of the needles of said two temporarily inactive arcs of needles on the first and second cylinders (13, 11) are brought into operation on completion of the knitting with reciprocating motion of said at least one part (3A, 5A, 3B, 5B) of the body portion (1), forming a connection line (CC) joining said two leg portions (9 A, 9B); wherein at least one partial starting course of one (9 A) of said leg portions (9 A, 9B) is knitted by one (13) of said first and second cylinders (13, 11) with float stitches that are knitted together with at least one partial starting course of the other (9B) of said leg portions, knitted by the respective temporarily inactive arc (C) of needles of the other (11) of said first and second cylinders (13, 11), to attach the first leg portion and the second leg portion (9 A, 9B) together along a crotch line (CC).

2. Method according to claim 1, characterized in that some of the needles of the temporarily inactive arc (C) of needles of one (11) of said first and second cylinders (13, 11) are extracted to retain float stitches formed by the other (13) of said first and second cylinders (13, 11) along said crotch line (CC), during the knitting of a first part of the first leg portion (9 A).

3. Method according to claim 1 or 2, characterized in that one of said first and second cylinders (13, 11) is axially offset in relation to the other during a step for knitting the float stitches together with said at least one partial starting course.

4. Method according to claim 3, characterized in that some of the needles of the temporarily inactive arc (C) of needles on one (11) of said first and second cylinders (13, 11) are extracted, knitting said first part of the first leg portion (9 A) with a continuous motion using the other (13) of said first and second cylinders (13, 11), while keeping inactive the needles of said other (13) of said first and second cylinders (13, 11) corresponding to the needles extracted from the one (11) of said first and second cylinders (13, 11).

5. Method according to claim 4, characterized in that alternate needles are extracted from the temporarily inactive arc (C) of needles.

6. Method according to claim 4 or 5, characterized in that the extracted needles are selected 1:1 along the temporarily inactive arc (C) of needles on the other (11) of said first and second cylinders (13, 11).

7. Method according to one or more of the claims from 3 to 6, characterized in that, after a first part of said first leg portion (9 A) has been knitted, the first and second cylinders (13, 11) are restored to a position substantially coaxial to one another and distanced from one another in the axial direction, and the knitting of the second leg portion (9B) begins with the other (11) of said first and second cylinders (13, 11), while the knitting of the first leg portion (9 A) continues with the one (13) of said first and second cylinders (13, 11).

8. Method according to one or more of the previous claims, characterized in that, on completion of the knitting of said at least one part (3A, 5A, 3B, 5B) of the body portion (1) by means of the reciprocating motion of the first and second cylinders (13, 11), courses of stitches are knitted on said first cylinder (13) and on said second cylinder (11) comprising starting fabric courses along a line corresponding to said temporarily inactive arc (C) of needles in the first and second cylinders (13, 11); and wherein, on one (13) of said first and second cylinders (13, 11), knitting with a continuous motion of the first leg portion (9 A) subsequently begins with the formation of float stitches along the temporarily inactive arc (C) of needles of said one cylinder (13), said float stitches being retained by needles extracted along the temporarily inactive arc (C) of needles of the other (11) of said cylinders, the knitting of said first leg portion continuing until the length of the leg portion thus formed suffices to distance said first cylinder and said second cylinder (13, 11) from one another enough to enable the simultaneous knitting in a continuous motion of said first leg portion (9 A) on said one cylinder (13) and of said second leg portion (9B) on said other cylinder (11).

9. Method according to one or more of the previous claims, characterized in that said at least one part (3A, 5A, 3B, 5B) of the body portion is knitted with a double feed on the first cylinder (13) and a double feed on the second cylinder (11), and the leg portions are completed by knitting with four feeds on each of said first and second cylinders (13, 11).

10. Method according to claim 1 , characterized by the following steps:

a) controlling the needles of the temporarily inactive arc (C) of needles in the second cylinder (11) to produce fabric starting courses with said needles of the temporarily inactive arc (C) of needles;

b) reversing the direction of rotation of the first and second cylinders (13, 11) and controlling the needles of the temporarily inactive arc (C) of needles in the first cylinder (13) to knit fabric starting courses;

c) extracting some of the needles of the temporarily inactive arc (C) of needles in the second cylinder (11), while all the needles in the first cylinder (13) are activated except those aligned with the needles extracted in the second cylinder (11), the activated needles of the temporarily inactive arc (C) of needles in the first cylinder (13) coming in between the needles extracted in the second cylinder (11) and said activated needles in the second cylinder taking up and retaining float stitches produced by the first cylinder (13);

d) keeping said needles of the temporarily inactive arc (C) of needles in the second cylinder (11) in an extracted position, and mutually axially offsetting said first and second cylinders (13, 11);

e) continuing the knitting of said first leg portion (9 A) with the first cylinder (13), forming a first piece of fabric (W) for the first leg portion (9 A), while keeping said needles of the temporarily inactive arc (C) of needles in the second cylinder (11) extracted;

f) bringing said first cylinder (13) and said second cylinder (11) again to a position coaxial to one another and distancing the first cylinder (13) and second cylinder (11) from one another, parallel to their respective axes; g) starting the knitting of a second leg portion (9B) with the second cylinder (11), while the first cylinder (13) continues to knit the first leg portion (9A).

11. Method according to claim 1, characterized in that the first leg portion (9 A) and the second leg portion (9B) are attached together along the crotch line (CC) by means of the following operating steps:

a) while, on completion of the knitting of said at least one part (3A, 5A, 3B, 5B) of the body portion, a further reciprocating movement is completed in one direction (F3) to form the last course (A2) of said at least one part (5A, 5B) of the body portion (1) with the respective feeds (3 OB) with the second (11) of said first and second cylinders (13, 11), at least some of the needles of the temporarily inactive arc (C) of needles in said second cylinder (11) are activated to produce two fabric starting courses in line with said temporarily inactive arc (C) of needles in the second cylinder (11);

b) the direction of rotation of the first and second cylinders (13, 11) is reversed to complete a first rotation with a continuous motion (F2) and, while all the needles of said second cylinder (11) are kept inactive, at least some of the needles of the temporarily inactive arc (C) of needles in the first cylinder (13) are activated to obtain two fabric starting courses along said temporarily inactive arc (C) of needles in the first cylinder (13);

c) while all the needles in the first cylinder (13) continue knitting to produce a first part of a first (9A) of said leg portions, alternate needles of the temporarily inactive arc (C) of needles in the second cylinder (11) are extracted, whereas all the needles in the first cylinder (13) are activated except for those aligned with the needles extracted in the second cylinder (11), the needles left inactive in the first cylinder (13) being left on a level with the respective sinkers, so that when the needles activated in the temporarily inactive arc (C) of needles in the first cylinder (13) pass in front of the respective feeds (5 OB), they come to be in between the needles extracted in the second cylinder (11), and the latter take up and retain the float stitches produced by the first cylinder (13) along said temporarily inactive arc (C) of needles;

d) the needles of the temporarily inactive arc (C) of needles in the second cylinder (11) are kept extracted while the knitting of the first leg portion (9 A) continues with the first cylinder (13), the first and second cylinders (13, 11) being offset in relation to one another by separating their axes by a distance (Yl) such that, passing in front of said feeds (5 OB) in the first cylinder (13) that are producing courses of the first leg portion (9 A), the needles extracted on the temporarily inactive arc (C) of needles of the second cylinder (11) that have taken up said float stitches are kept clear of the feeds (50B) in the first cylinder (13) so that they can no longer take up the yarns, although they continue to retain said float stitches; e) the needles of the temporarily inactive arc (C) of needles of the second cylinder (11) are kept extracted while the knitting of the first leg portion (9 A) continues with the first cylinder (13) by means of the respective feeds (50B) up until a portion of fabric (W) thus produced has reached a sufficient length (Z2) to enable the simultaneous knitting of the first and second leg portions (9 A, 9B) on the first and second cylinders (13, 11), also enabling the previously-extracted needles of the temporarily inactive arc (C) of needles in the second cylinder (11) to be retracted, bringing them with their latch-hooks on a level with the loop transfer plane of the sinkers of the second cylinder (11), and thereby juxtaposing the float stitches produced by the first cylinder (13), and also the first courses of said portion of fabric (W) of the first leg portion (9 A), with the loop transfer plane of the sinkers of the second cylinder (11);

f) the first and second cylinders (13, 11) are returned to a mutually coaxial position, the distance between them corresponding to said distance (Z2) between the loop transfer planes of the respective sinkers, and the preparation of the second leg portion (9B) begins with the second cylinder (11).

12. Method according to one or more of the previous claims, characterized in that, after the first cylinder (13) has been used to knit a first course of stitches with first float stitches of alternate needles of the first leg portion (9 A) in a binding sub-step, taking up said first float stitches with needles of the temporarily inactive arc (C) of needles of the second cylinder (11), said first and second cylinders (13, 11) are offset at an angle to one another corresponding to at least one needle pitch, and said first cylinder (13) is used to knit at least a second starting course of the first leg portion (9 A) with second float stitches offset in relation to the first float stitches, continuing to take up said second float stitches with said needles of the temporarily inactive arc (C) of needles of the second cylinder (11), and thus beginning to knit the second leg portion (9B), knitting said first and second stitches together.

13. Method according to one or more of the previous claims, characterized in that said needles of the temporarily inactive arc (C) of needles that take up float stitches of starting courses of the first leg portion (9A) are evenly distributed along said temporarily inactive arc (C) of needles.

14. Method according to claim 13, characterized in that said needles of the temporarily inactive arc (C) of needles that take up float stitches of starting courses of the first leg portion (9A) are distributed along said temporarily inactive arc (C) of needles in a 1:1 distribution.

15. Method according to one or more of the previous claims, characterized in that, during the knitting of the body portion and the knitting together step, the first and second cylinders (13, 11) are axially distanced from one another so that the distance (Zl) between the loop transfer planes of the respective sinkers amounts to at least the distance between the free end of the needles and the tip of the opened latches on the needles, to enable knitting on at least one feed of one cylinder at a time.

16. A double-cylinder circular knitting machine for manufacturing a knitted garment with a body portion (1) and two leg portions (9 A, 9B), comprising a first cylinder (12) and a second cylinder (13) one o top of the other, characterized in that it is programmed to implement a method according to one or more of the previous claims.

17. A double-cylinder circular knitting machine for manufacturing a knitted garment with a body portion (1) and two leg portions (9 A, 9B), comprising a first cylinder (13) with a first axis and a second cylinder (11) with a second axis arranged one on top of the other, characterized in that it comprises a device (58, 58A, 60) for offsetting the first cylinder in relation to the second cylinder (13, 11), separating said first axis and said second axis in relation to one another.

18. Machine according to claim 17, characterized in that it comprises a device for moving said first cylinder (13) and said second cylinder (11) mutually closer together or further apart, parallel to said first axis and second axis, so that the first cylinder and the second cylinder alternately take two positions at two established distances from one another, a first distance (Zl) being for knitting at least one part (3 A, 5 A, 3B, 5B) of the body portion (1) with a reciprocating motion of the first and second cylinders (13, 11) to perform a binding step between the first leg portion (9 A) and the second leg portion (9B); and a second distance (Z2), greater than the first distance (Zl), for simultaneously knitting the first leg portion (9 A) and the second leg portion (9B) with a continuous motion.

19. Machine according to one or more of claims 16 to 18, characterized in that it comprises a device (78, 70, 92) for the angular displacement of said first and second cylinders (13, 11) in relation to one another corresponding to at least one needle pitch.

20. Machine according to one or more of claims 16 to 19, characterized in that it comprises four feeds for each of said first and second cylinders (13, 11).

21. Machine according to one or more of claims 16 to 20, characterized in that each of said first and second cylinders (13, 11) has four feeds (50A-50D; 30A-30D) for the simultaneous knitting of the first leg portion (9 A) and second leg portion (9B) with a continuous motion, two adjacent feeds (50B, 30B) of each cylinder also being used for knitting with a reciprocating motion at least a part (3A, 5A, 3B, 5B) of the body portion and at least a part of the step for binding the first leg portion and the second leg portion.

22. A knitted garment comprising a body portion (1) and two leg portions (9 A, 9B) joined along a crotch line (CC), wherein said body portion and said leg portions are formed of a continuously knitted fabric with no seams; and wherein, in the crotch area, there is a line for joining the two leg portions formed by at least a partial interknitted course common to the two leg portions, said interknitted common course having a partial fabric starting course on one of said two leg portions to which float stitches formed along a partial fabric starting course on the other of said two leg portions are knitted.

23. Knitted garment according to claim 22, wherein the body portion comprises at least one upper part formed of two parts joined along two interknitted lines (m, n) extending respectively on a front portion and a rear portion of the garment; and wherein the front interknitted line is joined to the rear interknitted line by the common courses between the two leg portions along said crotch seam (CC).

24. Knitted garment according to claim 22 or 23, comprising an elastic edge (3A, 3B) from which columns of stitches extend along the body portion, forming a single tubular fabric and subsequently being divided to form the two leg portions (9 A, 9B), except for the columns of stitches that form the internal area of the leg portions 9A, 9B and that start in line with said partial interknitted course common to the two leg portions.