Classifications

• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04B—KNITTING
  • D04B9/00—Circular knitting machines with independently-movable needles
  • D04B9/10—Circular knitting machines with independently-movable needles with two needle cylinders for purl work or for Links-Links loop formation
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04B—KNITTING
  • D04B1/00—Weft knitting processes for the production of fabrics or articles not dependent on the use of particular machines; Fabrics or articles defined by such processes
  • D04B1/22—Weft knitting processes for the production of fabrics or articles not dependent on the use of particular machines; Fabrics or articles defined by such processes specially adapted for knitting goods of particular configuration
  • D04B1/24—Weft knitting processes for the production of fabrics or articles not dependent on the use of particular machines; Fabrics or articles defined by such processes specially adapted for knitting goods of particular configuration wearing apparel
  • D04B1/243—Weft knitting processes for the production of fabrics or articles not dependent on the use of particular machines; Fabrics or articles defined by such processes specially adapted for knitting goods of particular configuration wearing apparel upper parts of panties; pants
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04B—KNITTING
  • D04B15/00—Details of, or auxiliary devices incorporated in, weft knitting machines, restricted to machines of this kind
  • D04B15/94—Driving-gear not otherwise provided for

Definitions

• 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.
• pantyhose 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• leg portions with a continuous rotating motion of the first cylinder and of the second cylinder, each cylinder knitting one of the leg portions;
• 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.
• 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).
• 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.
• 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.
• 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.
• 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.
• the two leg portions 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.
• 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.
• 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 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).
• the method used to produce the connection between the leg portions along the crotch line involves the following set of steps:
• 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.
• the binding step the intermediate knitting 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.
• 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:
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• the machine also advantageously involves a device for angularly offsetting the two cylinders by at least one needle pitch during the binding step.
• 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.
• the feeds of each cylinder being arranged mainly at 90° angles to one another and angularly aligned with those of the other cylinder.
• 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.
• 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.
• 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 ⁇ 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 ⁇ - ⁇ 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 ⁇ - ⁇ 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.
• 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.
• 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.
• 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.
• 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.
• the upper head comprises a supporting member 36 that, by means of bearings 36 A (Fig. 17), supports the upper needle cylinder 13.
• 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).
• 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.
• 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.
• 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.
• the second jack 54 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.
• the transmission of the movement between the cylinders 11 and 13 comprises a coupling shaft 62 (see also Figs.
• 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.
• 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.
• 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.
• the same numerals and symbols indicate the same parts of the machine in the various arrangements. More in particular, Figs. 22 to 33 show:
• 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.
• Figs. 22 to 33 show those the stitch cams which are excluded from the process with dotted lines.
• 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 ;
• the outlets 50A, 30A, which are radially extractable, are shown with a dotted line in the steps during in which they are extracted.
• 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.
• the trajectories of the needle latch-hooks along the rising and falling trajectory defined by the stitch forming cams are shown.
• 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.
• 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).
• the term “lowering” is used generically to indicate the movement for retracting the needles inside their respective cylinders.
• 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.
• 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.
• 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.
• the upper head works with two feeds of yarn coinciding with the yarn- guide outlets 50B (see also Fig.
• 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.
• 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.
• not all the needles of the cylinders 11 and 13 are activated during knitting of the body portion.
• 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.
• 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.
• 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).
• a current of air is generated from above by means of a traditional suction system not shown in the drawing.
• a traditional suction system not shown in the drawing.
• 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.
• the right leg portion 9B (as you look at Fig.
• 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:
• the needles activated in the second feed 3 OB are suitably selected.
• 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).
• 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.
• 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.
• 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.
• 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 ;
• 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.
• 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 .
• 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.
• 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.
• 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.
• 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.
• RI1 and RI2 indicate the first two courses of stitches formed along the arc or crotch line CC.
• 15D- I indicates the raised (i.e. extracted) needles in the odd-numbered positions of the lower cylinder 11 in the binding step
• 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
• 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.

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• Knitting Of Fabric (AREA)
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• 2010
  • 2010-07-30 IT ITFI2010A000165A patent/IT1401279B1/it active
• 2011
  • 2011-07-27 WO PCT/IT2011/000269 patent/WO2012014246A1/en active Application Filing
  • 2011-07-29 TW TW100126903A patent/TW201207180A/zh unknown

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