Conti, Paolo (Via Neri di Bicci, 14 Firenze, I-50143, IT)
| 1. | A method for forming a closed toe in a tubular knitted article, comprising the steps of: setting two end flaps of said article alongside one another, tensioning transversely an edge of said article; tensioning longitudinally said article, aligning the loops of at least one first row of stitches together and the loops of at least one second row of stitches together of said end flaps set alongside one another; sewing together the aligned loops of said second row of stitches; and opening the loops of the first row of stitches. |
| 2. | The method according to Claim 1, comprising the steps of: providing at least one third row of stitches, arranged on the opposite side of said first row of stitches with respect to said second row of stitches, said third row of stitches being formed by a yarn of greater thickness; and tensioning longitudinally said article, bringing said third row of stitches up against said contrast member. |
| 3. | The method according to Claim 2, in which said contrast member is formed by a pair of bars set alongside one another. |
| 4. | The method according to one or more of the foregoing claims, in which said first row of stitches is opened by cutting the respective loops. |
| 5. | The method according to Claims 3 and 4, comprising the steps of: setting a cutting member inside said bars set alongside one another; and cutting the loops of said row using said cutting member. |
| 6. | The method according to one or more of the foregoing claims, in which the loops of said second row are sewn together by joining each loop of a first of said two flaps to a corresponding loop of a second of said two flaps by means of a stitch formed by a sewing thread. |
| 7. | The method according to Claim 6, in which said sewing thread forms at least one chain of stitches, in which intercalated between the stitches that join the two flaps are stitches that do not join the two flaps of the tubular article. |
| 8. | The method according to one or more of Claims 1 to 3, in which said loops of the first row are made of destructible yarn. |
| 9. | The method according to Claim 8, in which said destructible yarn is a yarn that can be destroyed by heating. |
| 10. | The method according to one or more of the foregoing claims, in which the loops of said at least one second row are sewn with a seam having a pitch that is smaller than the pitch of said loops. |
| 11. | The method according to Claim 10, in which the loops of said at least one second row are sewn with a sewing'pitch equal to or smaller than one half of the pitch of said loops. |
| 12. | A device for sewing two end flaps of a tubular knitted article and for forming a closed toe of said article, said device comprising in combination: transversetensioning means for tensioning transversely said tubular article, setting said end flaps alongside one another; a contrast member and means for tensioning longitudinally said tubular article, bringing said end flaps set alongside one another up against said contrast member; and sewing means with at least one needle,. for sewing together the flaps set alongside one another and set between said contrast member and said longitudinaltensioning means, said sewing means forming sewing loops that join opposed loops of said two flaps together. |
| 13. | The device according to Claim 12, in which said contrast member comprises a pair of basically rectilinear bars set alongside one another. |
| 14. | The device according to Claim 13, in which said bars are associated to a cutting member. |
| 15. | The device according to Claim 14, in which said cutting member comprises a blade housed in a seat made in one of said rectilinear bars and a contrast channel made in the other of said rectilinear bars. |
| 16. | The device according to one or more of Claims 12 to 15, in which said longitudinaltensioning means comprise a cyclically mobile element synchronized to the movement of said needle, which tensions the article longitudinally when the needle penetrates inside it and releases the article to enable movement of relative advance between the needle and the article to make consecutive sewing stitches. |
| 17. | The device according to Claim 16, in which said mobile element is controlled by means of a cam. |
Basically, the aforesaid patent application describes a method for forming a closed toe in a tubular knitted article, comprising the steps of: setting two end flaps of said article alongside one another; inserting in the loops of at least one first row of stitches of said end flaps a comb-like structure comprising a plurality of teeth; sewing together the loops of at least one second row of stitches, arranged between said first row of stitches and the body of the tubular article ; and opening the loops of the first row of stitches.
It has now been noted, and it forms a subject of the present invention, that it is possible to obtain a seam of a comparable quality, without introducing the comb-like structure inside the row of stitches above the row to be sewn.
Consequently, the present invention relates to a method for forming a closed toe in a tubular knitted article, comprising the steps of: - setting two end flaps of said article alongside one another, tensioning transversely an edge of said article ; - tensioning longitudinally said article, aligning the loops of at least one first row of stitches together and the loops of at least one second row of stitches together of said end flaps set alongside one another; - sewing together the aligned loops of said second row of stitches; and -opening the'loops of the first row of stitches.
The longitudinal tensioning is advantageously obtained, for instance, by providing at least one third row of stitches, arranged on the opposite side of said first row of stitches with respect to the second row of stitches, said third row of stitches being formed by a yarn of greater thickness. In this way, it is possible to tension the article longitudinally, bringing the third row of stitches
up against a contrast member. The third row of stitches may be a portion of an edge of greater thickness of the article, which is then eliminated by opening the loops of the first row of stitches.
The loops of the first row of stitches may be opened by cutting, or else by using a destructible yarn to form them, for instance a material that melts with heat, which can be eliminated in a subsequent dyeing step.
Further advantageous characteristics of the method according to the present invention are specified in the annexed claims.
The invention also regards a device for sewing two end flaps of a tubular knitted article and for forming a closed toe of said article, said device comprising in combination: - transverse-tensioning means for tensioning transversely said tubular' article, setting said end flaps alongside one another; - a contrast member and means for tensioning longitudinally said tubular article, bringing said end flaps set alongside one another up against said contrast member; and - sewing means with at least one needle, for sewing together the flaps set alongside one another and set between said contrast member and said longitudinal-tensioning means, said sewing means forming sewing loops that join opposed loops of said two flaps together.
In practice, the contrast member can comprise a pair of basically rectilinear bars set alongside one another, which can be associated to a cutting member, for instance a blade housed inside the bars themselves.
The longitudinal-tensioning means may advantageously comprise a cyclically mobile element synchronized to the movement of said needle, which tensions the article longitudinally when the needle penetrates inside it and releases the article to enable movement of relative advance between the needle and the article to form consecutive sewing stitches.
Further advantageous characteristics of the device according to the invention are specified in the annexed claims.
A better understanding of the present invention will be provided by the ensuing description and by the attached drawings, which illustrate a practical,
non-limiting example of embodiment of the invention. In greater detail, in the drawings: Fig. 1 shows a perspective view of a device invention for extraction of the tubular article from a circular knitting machine equipped with a device according to the present for closing the toe of the article ; Fig. 2 is a longitudinal cross-sectional view of the tubular article in the step prior to start of sewing; Fig. 3 is a local longitudinal cross-sectional view in a sewing step; Fig. 4 is an enlargement of Fig. 3; Fig. 4A shows a detail of a portion of fabric of the tubular article ; Figs. 5 to 8 illustrate successive steps of cutting of the loops of the first row of stitches and elimination of the yarn residue; Fig. 9 shows a schematic detail of the textile structure of the end edge of the tubular article ; Fig. 10 shows a schematic detail of the second row of stitches, on which sewing is carried out; and Fig. 11 illustrates the structure of Fig. 12 after cutting of the loops of the first row of stitches.
Fig. 1 shows a perspective view of a device, designated as a whole by 501, for picking up and closing the toe of the tubular article produced by a circular knitting machine 503. The details of the device 501, except for the means for closing the toe of the article, are described in detail in the above- mentioned prior application of the present applicant, to which reference is made. In said prior application, the device is designated by 1. The reference number 513 designates a suction duct by means of which the article is extracted from the circular machine 503 and presented to the sewing members, with modalities similar to what is described in the prior application.
Fig. 2 shows a longitudinal cross section of the end region of the duct 513 of the device 501, where the tubular article M has been set for carrying out sewing of the toe. The modalities with which the article M is brought to the configuration illustrated in Fig. 2 are described in detail in the prior patent application. The reference number 539 designates a unit which is
longitudinally mobile along the duct 513 and which carries a plurality of pushers 547 associated to actuators 549. The mobile unit 539 has the function, as already described in the prior application, of carrying the article outside the suction duct 513 and of tensioning said article longitudinally.
Set above the duct 513 is a pick-up member 571 with brackets 573 that constitute means of transverse tensioning of the article. These brackets are inserted in the tubular article and divaricated in a direction orthogonal to the plane of Fig. 2 to bring the end flaps L1, L2 of the edge B2 of the article M to set themselves alongside one another. Set underneath the brackets 573 is a pair of approximately rectilinear and mutually parallel bars, designated by 577 and 579. These are set alongside one another until they assume a distance such as not to compress the fabric that forms the article, but such as to withhold the edge B2 of the article itself, said edge being made with a yarn of greater thickness. The drawing of the article M longitudinally, downwards, for instance by the unit 539, brings the edge B of the article itself to bear upon the top surface of the bars 577,579, as is illustrated in detail in Fig. 3 and even more clearly in the enlarged view of Fig. 4.
Set inside the bar 579 is a cutter blade 587, provided with a movement of extraction from a seat set in the bar 579 itself, whilst in the bar 577 there is made a contrast channel 588 within which the blade 587 can penetrate when it is made to project from the bar 579, for the purposes described hereinafter.
In addition, associated to the device 501 is a sewing machine, designated as a whole by 595, which is equipped with a needle 596 that co- operates with a resting plate 598 (Figs. 3,4) with an opening 600 for the passage of the needle.
As illustrated in Figs. 3 and 4, set underneath the pair of bars 577 and 579 and facing the plate 598 is a mobile element, designated as a whole by 602, equipped with three blocks 604,606,608 constituting means for picking up and drawing along the fabric forming the article M. The mobile element 602 is connected by means of a cam 610 to a rotating shaft 612 and is moreover guided, by means of a groove 614, by a fixed pin 616. With this arrangement, when the shaft 612 rotates about its own axis, the mobile element 602
oscillates about the axis of the pin 616 and translates with respect to the latter so that the blocks 604,606,608 are cyclically pressed on the fabric of the article M, which is thus gripped between said blocks and the plate 598. The movement of translation of the mobile element 602 tends to draw the fabric of the article M downwards, so causing a cyclic tensioning thereof in the longitudinal direction. The movement of the mobile element 602 is synchronized with the movement of the needle 596 in such a way that the drawing downwards of the fabric forming the article M by the blocks 604, 606, 608 and by the contrast exerted by the contrast bars 577,579 causes stretching of the stitches of the fabric that are comprised between the block 604 and the bars 577, 579 before penetration of the needle 596. This facilitates penetration of the needle 596 through a pair of loops or stitches which are mutually aligned and belong to the two flaps L1 and L2. Drawing may cease when the needle has penetrated into the knitted fabric of the tubular article. In order to improve gripping, the block 604 has (as may be seen, in particular, in the enlargement of Fig. 4) a concave active surface.
Operation of the device is as described in what follows.
When the article M with the flaps defining the end edge B2 is found in the configuration of Fig. 2, the two end flaps L1, L2 of the article have been set alongside one another by the divarication performed by the brackets 573.
The fabric of the article is then tensioned transversely. A longitudinal tension applied to the article has brought the thicker part of the end edge, and in particular the row of stitches formed by a thick row FG (Fig. 4), bearing upon the bars 577,579 without these squeezing the remaining part of the fabric. A first row of stitches, designated by X1, comes to occupy a position between the bars 577,579.
The sewing machine 595 is now made to advance parallel to the bars 577,579 so that the needle 596 can form the chain that sews together the loops of the row of knitting designated by X3. The sewing machine 595 advances integrally with the plate 598 and the mobile element 602, which grips and releases the fabric of the tubular article M cyclically against the plate 598 in a synchronous way with the movement of the needle, thus enabling
relative advance between the plate 598 and the fabric of the article M.
At the end of sewing of the flaps L1 and L2, the article M is gripped, below the seam C made by the needle 596, by a pair of retention bars 605 (Fig. 1 and Figs. 5-8) that have been made to advance integrally with the sewing machine 595. It is now possible to cut the loops or stitches of the first row X1, which is at the height of the contrast bars 577,579, by means of the blade 587 housed in the bar 579. The cutting operation is illustrated in Figs. 5 and 6, whilst Fig. 7 shows the edge of the article M after closing by means of the seam C and cutting of the loops of the row X1. The residue of yarn generated by cutting of the row of loops X1 is eliminated by a suction mouth and a brush (Fig. 8) or other equivalent means.
Longitudinal and transverse tensioning of the article in a position corresponding to the row of stitches X1 enables distension of the rows X1 and X3 and setting alongside one another of the loops belonging to the flaps L1 and L2 of the row X3. The subsequent sewing performed with the needle 596 thus assumes a configuration equivalent to the one obtained by linking, in so far as each pair of corresponding loops of the flaps L1, L2 of the row X3 are joined by a stitch or loop generated by the needle 596 with the corresponding sewing thread. In practice, to prevent accidental skipping of a pair of loops of the row X3, the needle 596 will form sewing loops with a smaller pitch, for example half the pitch of the loops of the row X3, which must be sewn together. In this way, for each loop or stitch formed by the needle 596 that joins two loops of the row X3 together, there will, for example, be a free loop or stitch of sewing, i. e., one that does not engage the yarn of the article M.
This can be seen in the schematic representations of the textile structure of the edge B2 of the article and of the row X3 of sewing shown in Figs. 9 and 10.
More in particular Fig. 9 shows a portion of the area of the edge B2 of the tubular article. The reference X1 designates the row of stitches or loops BX1, which in the sewing operation, are at the height of the contrast bars 577, 579. In the example illustrated in Fig. 9, these loops BX1 have a length greater than that of the remaining loops BX set underneath, which are the
ones forming the body of the tubular article.
Above the row X1 there is a plurality of rows X2 made with the same yarn or with a yarn of poorer quality than that of the one forming the rows of loops or stitches BX underneath. The loops or stitches of the rows X2 may be of the same size as the loops BX. The first of the rows X2 is made with a yarn FG of greater thickness, as mentioned previously, so as to cause the article to bear upon the bars 577,579.
Once again in Fig. 9 the seam C is shown, which is formed by the needle 596 of the sewing machine 595. As may be seen in this figure, the seam C is performed in an area corresponding to the row of stitches X3 underneath the row of stitches X1. As has already been mentioned, the pitch of the seam C is smaller than the pitch of the loops or stitches of the row X3 and hence than that of the row X1 and of any other row of the article.
Basically, the loops of the row X3 are sewn together by joining the loops of the flap L1 to a corresponding loop of the flap L2 by means of a stitch formed by a sewing thread forming the seam C. This sewing thread forms a chain of stitches, in which intercalated between the stitches joining the two flaps are stitches that do not join the two flaps of the tubular article.
Fig. 10 shows two portions of the row of stitches or loops X3 on which sewing is performed. The isolated representation of this individual row of stitches or loops illustrates clearly the sewing technique, obtained with a pitch smaller than the pitch of the loops. Designated by XC1 and XC2 are the loops formed by the sewing thread. More in particular, the loops XC1 are the ones that engage the thread forming the loops of both flaps set alongside one another of the edge B2 of the article M, whilst designated by XC2 are the loops formed by the sewing thread that do not join the two flaps. The seam is in this example a single chain stitch, but other embodiments are not ruled out.
Fig. 11 represents again the article in the area of sewing in a way similar to what is represented in Fig. 9, but after the cutting performed by the blade 587.
Figs. 9 and 11 are schematic illustrations of how the first of the rows X2, i. e., the one immediately subsequent to the row X1, is made with a yarn FG of
larger cross section, which may possibly be elastic. Instead of the first of the rows X2, the row immediately following may be made with the yarn of larger cross section. Alternatively, even more than one row can be made with yarn of greater thickness. The function of this yarn was illustrated previously with reference to the step of preparation of the article for sewing.
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