Improved process for manufacturing socks with hosiery machines and semiworked item obtained thereby

Abstract: The present invention relates to an improved process for manufacturing socks with hosiery machines and to a semiworked item obtained with the process. The process comprises successive steps for manufacturing a sock (10) starting from the leg (11) up to the tip (12). The tip (12) forming step is completed by knitting: a row of knitting (13) with increased loop length with respect to the already knitted tip rows, a first portion of knitting (14) constituted by a few rows of knitting knitted with a thinner thread with respect to the thread used to knit the first row (13) and, subsequently, a second portion of knitting (15) constituted by a few rows of knitting with a thicker thread with respect to the thread used to knit the first portion of knitting (14).

Description: The present invention relates to an improved process for manufacturing socks with hosiery machines and to a semiworked item obtained with said process. As is known, cotton or wool socks, in particular for men, are currently generally manufactured on circular knitting machines which provide a semiworked product, open at the tip, which requires a subsequent finishing operation, by means of which the toe or tip is closed, in order to produce sock. This finishing operation is notoriously considered to be very important by sock manufacturers, since it largely determines the quality of the finished product. The tips of socks can be closed by linking or by means of mechanical sewing termed "blind" sewing. The linking operation is performed on appropriate machines and requires the manual placement of each individual loop, at the opening of the tip, on appropriate pins of the machine which are then affected by an extremely precise sewing so as to mutually join the various loops. Blind mechanical sewing is much easier and rapid to performs, since it does not require the placement of each individual loop of the open tip of the sock but a less precise positioning of the sock, which is then subjected to one or more sewing operations. The best-finished and most desirable socks are obtained by linking, especially due to the better finishing in the sewing region, which is scarcely detectable to the touch and, when the sock is worn, produces no unpleasant feelings, but is also advantageous from an aesthetic point of view since it has its own perfection of opposite threads sewn together in a harmonious and symmetrical manner, so much that linking can be visually recognized even apart from the tactile effect. Linking naturally entails a considerable use of specialized labor which unavoidably raises the retail cost of a pair of socks finished in this manner to high levels. Therefore, machines for blind mechanical sewing, which do not require loop-by-loop positioning and have been recently improved in their operating speed and in the durability of the sewing they perform, i.e. in the "hold" of the stitches, are used extensively. With machines of this type, an operator, even an unspecialized one, can finish up to 2500 pairs of socks per day, whereas with linking a very expert operator might achieve at the most the result of 300 pairs per day. The difference in terms of costs is therefore significant. On the other hand, the improvements in currently used machines which perform blind sewing have only marginally affected the quality of the sewing in terms of aesthetic quality and actual comfort for the user, since said sewing is in any case not only immediately recognizable as blindsewn and not linked but also necessarily causes a certain unpleasant feeling of discomfort to the person who wears socks finished in this way. It should be noted that the most modern circular knitting machines for manufacturing socks can be preset for preparing the tip of socks in a different manner depending on whether linking or mechanical blind sewing is intended to be used. In the case of linking, the open tip is ended with a row of knitting with longer loops with respect to the preceding row. Such row may be reinforced and is followed by a knitted trim which has a density substantially equal to that of the previously formed tip and is used exclusively for guiding during linking and is cut once linking is completed. If blind mechanical sewing is intended, the open tip is ended with a portion of knitting generally constituted by 4-5 rows, for a total length of 5 mm, of a polyamide thread which has a certain elasticity (such as for example Helanca™ or Lycra™) with tight knitting, followed by a knitted trim as in the preceding case. The presettings recommended by the companies which manufacture circular knitting machines for hosiery and machines which perform blind sewing have always been of the above described type, and it has never been possible to achieve a significant improvement in the type of sewing obtained with a blind sewing machine; the sewing produced thereby is very thick, hardly ever perfectly straight and aesthetically unpleasant. According to what has been explained above, it would therefore be desirable to obtain, by means of blind sewing, finished socks which have characteristics similar to those of linked socks. The aim of the present invention is to solve the above described problem by providing a process which allows to manufacture an open-tip sock which can be finished by mechanical blind sewing, whereby to obtain a finished sock which has, both aesthetically and to the touch, characteristics which are similar to those of socks finished by linking. Within the scope of this aim, an object of the invention is to provide a process which is simple to carry out on both rectilinear and circular knitting machines. Another object of the invention is to provide a process which allows extremely precise blind sewing during finishing. Further characteristics and advantages of the invention will become apparent from the description of a preferred but not exclusive embodiment of the process according to the invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein: figure 1 is a view of the tip or toe region of a sock prepared for linking with a known process; figure 2 is a view of the tip region of a sock prepared for blind sewing with a known process; and figure 3 is a view of the tip region of a sock prepared with the process according to the present invention. With reference to figure 1, in order to conventionally knit a sock 1 which is to be finished by blind sewing, after the steps of forming the leg, the heel, the foot 2 and the tip 3, a first portion of knitting 4, constituted by a few rows for an overall length of approximately 5 mm, is knitted with a thin and elastic thread, generally made of polyamide fiber, and a second portion of knitting 5 is knittec thereafter with a thicker thread. The first portion of knitting 4, which is to be affected by the sewing for closing the tip, therefore has a reduced thickness with respect to the thickness of the knitting in the actual tip region and with respect to the thickness of the knitting in the second portion of knitting 5. Said second portion of knitting 5 acts as guiding trim during the positioning of the sock on the sewing machine and during the sewing operation, but does not safely avoid the possibility of movements of the sewing point within the first portion of knitting 4, with consequent deformations of the sewing line which is very often non-rectilinear, with thickenings of said sewing. With reference to figure 2, in order to conventionally knit a sock 1a to be finished by linking, after the conventional steps of forming the leg, the heel, the foot 2a and the tip 3a, a row of knitting 4a, formed by loops with increased length with respect to the previously formed tip loops, is knitted, and a portion of knitting 5a with a stitch density similar to that of the tip 3a is then knitted. In order to perform the linking operation, each loop of the row of knitting 4a is fitted manually on a pin of the pin-holder ring of a linking machine. The portion of knitting 5a simplifies this operation. With reference to figure 3, in order to knit a sock 10 with the process according to the present invention, after forming the leg, the heel, the foot 11 and the tip 12 in a known manner, a row of knitting 13 with loops of increased length with respect to the previously knitted rows of the tip 12 is knitted; then a first portion of knitting 14, constituted by a few rows of knitting formed with a thinner thread with respect to the thread used for the row 13, is knitted, and a second portion of knitting 15 is finally knitted using a thicker thread with respect to the thread used to knit the first portion of knitting 14. Conveniently, the row 13 is knitted with the addition of a reinforcement thread by feeding the needles of the machine with two threads simultaneously in a per se known manner. The first portion of knitting 14 is preferably knitted with a helanca or Lycra polyamide thread so as to obtain a portion of knitting which has a reduced thickness and a certain elasticity. Said portion of knitting 14 is expediently constituted by approximately six rows of knitting. Finally, the second portion of knitting 15 has an overall length of approximately 1 cm and is preferably knitted using a low-cost thread, since it is to be eliminated after finishing. The process according to the invention can be easily performed on a known circular machine simply by setting said machine so that, after knitting the actual tip, it knits a row of knitting 13 with reduced stitch density, i.e. with longer loops. While this row of knitting is being knitted, an additional thread guide is activated simultaneously and feeds the reinforcement thread to the needles. These operations are easy to perform by modifying the actuation program of modern circular knitting machines. In order to knit the first portion of knitting 14 and the second portion of knitting 15, the machine is actuated as during the known preparation of the sock for mechanical blind sewing, described with reference to figure 1. It should be noted that in the tip of the sock prepared with the process according to the invention, the first portion of knitting 14, besides having a certain elasticity, has a reduced thickness with respect to the row of knitting 13 and to the second portion of knitting 15. Due to this fact, the first portion of knitting 14 can be rapidly and precisely positioned on the grip elements, generally clamps, with which blind sewing machines are provided. In practice, the jaws of a clamp engage the first portion of knitting 14 and the sock remains arranged correctly during sewing with no possibility of accidental movements, since the row 13 and the second portion of knitting 15 act as opposite shoulders by resting against the closed jaws of the clamp. In an example of an embodiment which has actually been carried out, the process according to the invention has been performed on a Lonati Goal model 362 single-cylinder circular knitting machine preset for blind mechanical sewing preparation. By acting on the actuation controls of the machine, in the manner known to any person skilled in the art, the stitch density is changed at the end of the forming of the actual tip so as to knit a row of knitting with reduced density with respect to the stitch density used in forming the actual tip, and an additional thread guide is simultaneously moved to knit so as to obtain a row of knitting with longer loops reinforced by the addition of a thread. The thread guides which fed the thread for forming the sock are then excluded from knitting, and thread guides which feed a helanca or Lycra thread are moved to knit so as to form consecutive rows of knitting, e.g., six rows. A further exchange of the thread guides is subsequently performed so as to exclude from the knitting the thread guides which bear the helanca or Lycra thread and move back into knitting the thread of guides bearing the same thread used to form the sock or a less valuable thread so as to form the second portion of knitting 15 for an overall length of approximately 1 cm of said portion. The sock thus prepared is inserted on a conventional sewing machine which performs blind sewing, and sewing with two passes in line is performed; the first sewing is performed with two 20/2 helanca threads at 28 stitches per 2.54 cm (28 stitches per inch), whereas the second sewing occurs with an 80/2 cotton thread and a 20/2 helanca thread at 20 stitches per 2.54 cm (20 stitches per inch). The result obtained was a perfectly rectilinear sewing with a thickness not perceivable to the touch, and with a considerable aesthetic effect due to the tidiness and uniformity of the stitches. Some experts to whom the sock thus finished was shown detected no differences with respect to finishing performed by linking. It should be noted that though the second sewing step with a cotton thread is not necessary, it provides a particular aesthetic effect which is suitable for giving the item the appearance of a true linking. In practice it has been observed that the process according to the invention fully achieves the intended aim, since it allows to obtain open-tip socks which can be subjected to finishing by means of blind mechanical sewing, and therefore with reduced manufacturing costs, while obtaining a product which is qualitatively comparable with socks finished by linking. The process thus conceived, as well as the semiworked item obtain thereby, are susceptible to numerous modifications and variations within the scope of the inventive concept defined by the independent claims; all the details may furthermore be replaced with technically equivalent elements. In practice, the materials employed, so long as compatible with the specific use, as well as the dimensions, may be any according to the requirements and the state of the art. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the scope of each element identified by way of example by such reference signs.

Claims: Improved process for manufacturing socks (10) on hosiery machines, comprising a leg forming step, a heel forming step, a foot forming step and a tip forming step, wherein said tip forming step is completed by knitting: a row of knitting (13) with increased loop length with respect to the already knitted tip rows, a first portion of knitting (14) constituted by a plurality of rows of knitting knitted with a thinner thread with respect to the thread used for knitting said first row, and subsequently a second portion of knitting (15) constituted by a plurality of rows of knitting, knitted with a thicker thread with respect to the thread used for knitting said first portion of knitting. Process according to claim 1, characterized in that a reinforcement thread is added while knitting said row of knitting with increased loop length. Process according to claim 1, characterized in that said first portion of knitting is knitted with a polyamide thread. Process according to claim 3, characterized in that said polyamide thread is made of Helanca™. Process according to claim 3, characterized in that said polyamide thread is made of Lycra™. Process according to one or more of the preceding claims, characterized in that said second portion of knitting is at least 1 cm long. Process according to claim 1, characterized in that said second portion of knitting is knitted with a less valuable thread with respect to the thread used to knit the sock. Process according to claim 1, characterized in that said first portion of knitting is constituted by approximately six rows of knitting. Process according to claim 1, characterized in that it is performed with a circular machine. Semiworked knitted item for manufacturing socks, comprising at the tip (12) of the sock (10) which is manufactured so that it is open and is intended to be closed by sewing, a final knitting which is composed, starting from the body of the sock, of a row of knitting (13) with increased loop length with respect to the preceding rows, characterized in that it comprises a first subsequent portion of knitting (14) constituted by a plurality of rows of knitting knitted with a thinner thread with respect to the thread used for said first row, and of a second portion of knitting (15) constituted by a plurality of rows of knitting knitted with a thicker thread with respect to the thread used for said first portion of knitting. Item according to claim 10, characterized in that said row of knitting with increased loop length comprises an additional reinforcement thread. Item according to claim 10, characterized in that said first portion of knitting is made of polyamide thread. Item according to claim 12, characterized in that said polyamide thread is constituted by a Helanca™ thread. Item according to claim 12, characterized in that said polyamide thread is constituted by a Lycra™ thread. Item according to claim 10, characterized in that said second portion of knitting has a length of approximately 1 cm. Item according to claim 10, characterized in that said second portion of knitting is knitted with a less valuable thread with respect to the thread used to knit the sock body. Item according to claim 10, characterized in that said first portion of knitting is constituted by approximately six rows of knitting.

Inventors: BETELLA PIETRO, METELLI CLAUDIO, POZZI GIANCARLO, SALVETTI SERGIO, BETELLA, PIETRO, METELLI, CLAUDIO, POZZI, GIANCARLO, SALVETTI, SERGIO
Applicants: CALBREV SRL, CONTI COMPLETT SPA, CALBREV S.R.L., CONTI COMPLETT S.P.A.
Application year: 1991
Main classification: D04B1
IPC codes: D04B1