DESCRIPTION

Technical Field

The present invention relates to a knitting method and to a circular knitting machine for the production of stockings, socks or the like.

In particular, the present invention relates to a method and a device for closing the toe of a knitted article formed on a knitting machine.

Background Art

In the production of knitted articles of manufacture, such as socks, stockings and the like, one of the major problems lies in the need of closing the toe of the article, i.e. the end portion thereof. This is normally accomplished in a separate stage and on a separate machine, after having completed the tubular article on a circular knitting machine.

Several attempts have been made in the art for simplifying and speeding up this particular step of the knitting process. Various methods and devices for closing the toe of a knitted article of manufacture are disclosed for example in IT-A-676,845, IT-A-685,974, IT-A-1,241,770, IT-A-1,205,775, EP-A-0 592 376, DE-A-16 35 992.

Objects of the Invention

Earlier patent application PCT/IT95/00072 (claiming priority from Italian patent application N. FI94A 88 of 17.05.94) and earlier patent application PCT/IT95/00099 (claiming priority from Italian patent application N. FI94A 125 of 16.06.94) belonging to the same applicant, relate to improved methods and devices for the automatic initial formation of a closed toe in a

tubular knitted article - such as a stocking or sock or a panty-hose leg - directly on the circular knitting machine with a needle cylinder on which said article is to be formed. The content of these earlier International patent applications is incorporated in the present specification. In said method, an initial edge of a pouch is formed by the needles of a first arc of approximately a semicircle, and after the pouch has been formed said initial edge is transferred to the needles of the opposite arc and is picked up by said needles. This is followed by circular knitting.

The present invention relates to an improvement aimed at obtaining greater regularity in the formation of the join of the initial edge to the needles of said opposite arc.

In particular, the invention relates to a mechanism of this type for closing the toe by means of an arrangement that can also be used in the presence - on the machine - of the conventional hook disk or plate.

The above mentioned object and other objects and advantages will become clear in the following text.

Summary of the Invention

The mechanism is of the type designed for transferring a knitted fabric formed by a portion of the needles to the opposite complementary portion of needles of the needle cylinder of a circular knitting machine, especially a hosiery knitting machine, for starting an article with the closure of its initial end, the machine comprising a throwing-over element of basically semicircular shape able to rotate about an axis extending approximately diametrically across the working area of the needles and equipped with a plurality of means for picking up the initial portion of the fabric. According to the invention, said throwing-over element is caused to rotate toward and into the cylinder, its pick-up elements being able to project radially and retract radially.

Said throwing-over element can be fitted underneath the plate that lies above the needle cylinder.

The mechanism may comprise, above the plate and rotating with it, a tubular structure with feet that engage with cams to bring about centrifugal and centripetal movements of said pick-up elements (hooks) for the transfer of the initial edge of the article. In one possible embodiment, said pick-up means are formed by expansions - especially spherical or suchlike expansions, provided they are solids of revolution - on the outermost ends of lines running inside flexible sheaths and terminating with springs that guide the lines; the outermost turn of each of the springs can interact with the corresponding outermost expansion in order to hold the fabric and continue to grip it during its transfer in a centripetally retracted position. Each line may also comprise, in addition to the outermost expansion that can interact with the outermost turn of the spring, a smaller expansion that doeε not interfere with the turns of the spring and that can hold the fabric gripped by the pick-up means in order to keep it close to the pick-up element, that is, in order to ensure that it does not move along the wire.

The mechanism may be equipped with hook elements by way of pick-up means, in which case the lines, which are made of metal and are elastically flexible, are so constructed that in the rest position they are bent; they therefore rotate about themselves as they move between the two positions adopted by the throwing-over element, in order to maintain a particular orientation so that said hooked pick-up elements do not let go of the fabric.

Said structure poεitioned above the plate of the hooks may comprise an axial tubular passage through which there pass the sheaths of the wires, and also mechanical drive means for operating the throwing-over element.

Brief Description of the Drawings

A fuller understanding of the invention will be derived from the following description and accompanying drawing, the latter showing a practical, non-limiting example of said invention. In the drawing:

Figs 1 - 7 show in axial section a number of phases in one cycle of transfer with a mechanism according to the invention;

Fig. 8 shows an enlarged detail identified by the arrow VIII in Fig. 3;

Fig. 9 shows schematically a throwing-over element in a view basically on IX-IX in Fig. 3, but with a number of different positions of the pick-up means;

Fig. 10 shows an enlarged detail indicated by the arrow X in Fig. 1;

Figs 11 - 14 show, in a number of phases, a modified form differing from the above example;

Fig. 15 shows an assembly for a pick-up element used with said modified form.

Detailed Description of the Invention

As illustrated in the accompanying drawing and with initial reference to Figs 1 - 10, the reference 1 denotes the needles εliding in the longitudinal trickε of a revolving needle cylinder (not illuεtrated but of a purely conventional type) . The reference 3 denoteε generally a hook diεk or plate, the hooks being labelled 5 and being of the radially mobile type, their arrangement and functionε being perfectly familiar. The plate 3 iε mounted on a tubular element 7 which revolveε with the plate around the εame axiε coinciding with the axiε of the needle cylinder, and which is turned by a conventional drive 9. Connected to the revolving unit comprising the plate 3 and tubular element 7 is another cylindrical element 12 that is axially hollow and comprises a serieε of longitudinal slide seatε 12A for feet 14, the purpose of which will be indicated later. The reference 16 denotes cams supported by the fixed frame of the machine and

acting on the butts of the feet 14 in order to move them up and down and place them in certain positions in their slide seatε for the purpoεeε indicated below. The axial paεεage through the tubular element 7 and that through the cylindrical element 12 - which are coaxial - can be uεed to accommodate elementε belonging to the mechanism in question.

As can also be seen in Fig. 9, there pivotε on the plate 3 of the hookε 5, about a diametrical axiε X—X perpendicular to the axiε of the needle cylinder, a throwing-over element 18 whose basic shape is that of a semicircular arc and that is able to rotate about the axis X—X in the directions of the double arrow fx to reach the position shown in Figε 1 - 3 on one side and the thrown-over position shown in Figs 4 - 7 and back again. In order to throw it over about the axis X— , a drive 20 is uεed which may conveniently take the form of a series of small drive pinions 20 driven by a rack 22 and by a rod 24 that controlε it and that iε driven via a collar 26 by an actuator 28. Control of the throwing over of the element 18 can also be provided by some other drive syεtem, provided it is compact and leaves sufficient room for other functionε in the paεεage running through the tubular element 7 and through the hollow cylindrical element 12.

Joined to the throwing-over element 18 are the endε of flexible εheathε 30; said ends joined to the throwing-over element 18 are arranged radially, while the other ends are joined at 32 to the tubular element 7. Metal wires 34, advantageously elastic metal εpring wires, can move inεide the flexible sheaths 30; each of the wires 34 projects radially from the end of the εheath attached to the element 18, and can move radially both centrifugally and centripetally. The individual metal wireε 34 are held (see also Fig. 10) by their respective feet 14, in such a way as to allow them to rotate about their axes, but not allowing them to undergo relative

axial movements; thiε iε done with a stop 36 - represented in practice by a screw - that traps the corresponding wire 34 between two small stops 34A integral with the end of the wire 34 inserted in the seat into which the stop 36 projects. In this way the wire 34 can be made to move axially inside the sheath 30 but is free to move about itεelf on itε own axiε. At the outermoεt end projecting radially from the throwing-over element 18, each wire 34 (see also and in particular Fig. 8) compriseε an outermost expansion 40 which may be approximately spherical, and, a short distance from the latter, a smaller expansion 42, also approximately spherical; both expansions 40 and 42 can also have other, nonspherical profileε, provided these are solidε of revolution about the axiε of the wire. In addition a spring 44 surrounds that part of each wire 34 that projects radially from the element 18. Said spring pushes against the member 18 and its outermost turn 40A can interact with the expansion 40, while the εmaller expansion 42 can move inεide the turnε of the spring 44.

When the asεembly of componentε deεcribed above is in the position shown in Fig. 1, that is, when commencing work, the wires 34 are moved down to project to their maximum extent out of the throwing-over element 18, which is turned toward the right-hand εide when viewing Figε 1 - 3. In this condition the expanεion 40 is on the outside of the ring of needles 1 and the smaller expansion 42 immediately inside the ring of needles, while the spring 44 is completely relaxed, its outermost turn 44A being behind the expanεion 42. When yarn beginε to be drawn and the first rows of loops begin to be formed, usually using alternating needles, one needle on and the other off, in order to commence work with the needle cylinder in reciprocating motion, the initial loops of fabric formed by the arc of working needles adjacent to the throwing-over element 18 (see Fig. 9), i.e. the needleε of arc A, are gripped between the two expanεionε 40 and 42 of the wires 34. On needle arc B, complementary

with and oppoεite arc A, a firεt row or first pair of rows of loops MB can be formed, being retained by the needles of arc B which remain inactive during the formation of the fabric that iε to form the initial cloεure of the toe of the article, aε indicated in the International applicationε mentioned hereinbefore.

After thiε firεt phase of gripping the initial rows of the fabric that is to form the closure of the toe, the wires 34 are gradually withdrawn in the centripetal direction, as can be seen by comparing Fig. l, Figs 2 and 3 and Fig. 8. The fabric TP that is to form the toe is produced by a reciprocating action of the needle cylinder and by increases and decreaseε in the length of εucceeding rows, in much the same way as when forming pouches for heels or the like or when forming conventional toes, and also as indicated in at least some of the International applications mentioned above. The needles of the active arc A thus produce a pouch of fabric TP which hangs between the needleε of arc A and the endε of the wireε 34 which are retracted in the centripetal direction; in thiε way the initial rowε of the fabric TP gripped by the expansion 40 are held fast by the preεεure of the outermost turn 44A of the spring 44 around each wire 34, which spring 44 is more or lesε gently compreεεed as the wire 34 iε retracted, that iε pulled back, centripetally, thereby shortening the amount of projection of the wire 34 beyond the point where the spring presseε againεt the throwing-over element 18. This leadε to the poεitionε shown in Figs 2, 3 and 8, and a sufficient amount of fabric is formed for the initial edge of the fabric TP to be able to be transferred, by gripping it between the expansions 40 and the outermost turn 44A of the spring 44 of each wire 34 and moving it acrosε to the needles of arc B opposite the arc of needles A where the fabric TP was formed. At this point the drive 20 and the components 22, 24, 26, 28 or equivalent components throw over the throwing-over element 18 from the position of Figs 1 - 3,

through a downward rotation, to the position of Fig. 4. The initial fabric remains gripped, i.e. trapped, between the expansion 40 and the outermost turn 44A.

The poεition of Fig. 4 iε next modified to that of Fig. 5 by moving the wires 34 so that the expansions 40 are moved out centrifugally until said expansions 40 and 42 are outεide of the needles of arc B; the needles of arc B can therefore pasε through the initial fabric gripped between the expanεionε 40 and 42 in an upward movement through said fabric with their latches open, when these needles are lifted. The outermost turn 44A of each spring 44 remains on the inside of the ring of needleε of arc B and doeε not therefore interfere with the operationε which theεe needleε are required _f to perform. The inner expansion 42 ensures that the fabric TP is positioned over the arc of needles B. The needles of arc B are then lowered after drawing the yarn which is fed to them for the start of the tubular formation of the article. Some means is provided for raising the latch, for example a spring wire as indicated at 50, which acts on the latcheε of the needleε of arc B to enεure that they cloεe when the needleε move down and emerge from the initial fabric of the toe portion TP; the initial rowε of thiε fabric TP are engaged by the yarn caught by the needles of arc B on their downward movement. The metal wires 34 are withdrawn centripetally and do not disturb the action of the needles of arc B. The loops previously gripped between the two expansionε 40 and 42 are easily released from the expansions 40 as the wires 34 retract centripetally to the position of Fig. 6 and then on to the position of Fig. 7. After an at least partial formation of the tubular fabric and hence the removal of the toe formed by the initial fabric TP from the plate, the throwing-over element 18 can be moved in the opposite direction to that previously described, returning it from the position of Figs 5, 6 and 7 back to the position of Figε 1 - 3, ready to εtart a new cycle of forming a toe at the commencement of work on a tubular

SUBSTITUTESHBETflHEa}

article. When commencing this new article the wire 34 of each sheath 30 will be advanced centrifugally so that its end fitted with the expansion 40 reaches a position outside the needles of arc A in order to grip the initial loops of the new cycle.

In the _, embodiment shown in Figε 11 - 15, only those parts of the components that are necessary to demonstrate the difference between thiε and the previouε embodiment are illustrated, with Fig. 10 also being reproduced at the top of Fig. 15. The same reference numerals as were used for the first example are used again for equivalent components in the modified embodiment depicted in Figs 11 - 15. The modification relates chiefly to the end of the metal wire 34, which comprises, instead of the two expansions 40 and 42, a hooked element 140. This is able to interact with the end turn 44A of the spring 44 in much the same way as envisaged with respect to the expansion 40. In the position of Fig. 11, which correspondε to the poεition of Fig. 1, the raising of the needles of arc A and the forming of the first rows with the yarn F with the needles selected one-to-one, enables the first rows to be held in the hook 140. With the withdrawal of the wire 34, which can be seen by comparing the position of Fig. 11 with the position of Fig. 12 (which is an intermediate position along the path about the axiε X-X of the throwing-over element 18) , the initial portion TP1 of the toe cloεure fabric TP remainε trapped between the hook 140 and the outermoεt turn 44A of the spring 44. In this embodiment the wire 34 is a spring metal wire which, in the rest position, has the shape shown in Fig. 15, that is to say bent with the concavity facing in the same direction as the open side of the hook 140. Hence the hook 140 is facing upward in the poεition of Fig. 11 with the εpring metal wire 34 curved in the same direction as its natural curvature spontaneously adopts. During the throwing over of the element 18 about the axis X-X, the wire 34 is forced elastically to

- 10 -

εtraighten and then curve in the oppoεite direction, cauεing the εpring wire 34 to rotate εpontaneously about itself, it being completely free to rotate both inside the sheath 30 and at the point where it iε anchored between the end expanεionε 34A at the oppoεite end from the hook 140, aε iε εhown in Fig. 10, previouεly diεcussed with respect to the firεt illuεtrative embodiment. The reεult iε that when the throwing-over element 18 moveε away from the poεition shown in Fig. 11 (corresponding to the position of Fig. 1) to the opposite position shown in Fig. 13 corresponding to the position shown in Fig. 4, the hook 140 of each wire 34 reorientates itself automatically upward, thereby gripping the fabric of the edge TPl of the fabric TP even when the wire 34 is pushed by the control feet 14 centrifugally out beyond the arc B of needles opposite the arc A on which the fabric TP was formed. When each wire 34 is withdrawn centripetally from the position of Fig. 13 to that of Fig. 14, the hook 140 releaseε itself easily from the fabric, abandoning it completely to the needleε of arc B that have now paεεed through it and then engage the outermoεt edge TPl of the fabric TP with the yarn Fl drawn by the raiεed needles (see Fig. 14) ; and said outermost edge TPl is thus engaged between the loop formed with said yarn Fl and the first loops formed by the needles of arc B, as indicated at MB in Fig. 14.

It will be understood that the drawing shows only an illustrative embodiment purely by way of a practical demonstration of the invention, it being possible for said invention to be altered as regards shapes and ^* arrangements without thereby departing from the εcope of the concept underlying εaid invention. The preεence of any reference numerals in the appended claims is purely for the purpose of facilitating the reading of the claims with reference to the description and drawing, and doeε not limit the scope of protection represented by the claims.