Process for manufacturing a semifinished product with circular knitting machines, in particular for producing undershirts, one-piece body garments or the like

Abstract: The process consists in producing a body (2,3) of knitting having a substantially tubular extension, and knitting portions (3) of said body (2,3), which are to be removed, with stitches using a number of threads which is smaller than the number of threads used for producing the remaining part (2,4) of the product (1).

Description: The present invention relates to a process for manufacturing a semi-finished product with circular knitting machines, in particular for producing undershirts, one-piece body garments or the like. As known from EP-A 0 037 629, tubular knitted products manufactured with circular knitting machines are used to produce undershirts with no lateral seams. Said products have a substantially uniform knitting along their entire extension, except for any possible ornamental patterns, and in order to produce undershirts they are first cut according to the required length, and four portions are subsequently removed at a longitudinal end of the product so as to respectively define the front and back neck-openings and the openings for the arms. When these four portions are removed, four flaps are defined and are subsequently sewn together in pairs so as to obtain the shoulders of the undershirt. A finishing border is applied along the cutting lines for the removal of the four portions, and the lower end of the undershirt is subjected to a hemming operation with the possible application of an elastic strip. With this process, the waste consequent to the removal of the portions corresponding to the neck- and arm openings considerably affect production costs, since the thread used for this kind of product is generally of high quality. The cutting operations furthermore generally require the use of templates in order to obtain sufficiently precise results, and imply relatively long times and in turn affect production costs. Semi-finished products for producing briefs are also known which are also manufactured with particular circular machines which are similar to circular knitting machines for manufacturing socks and stockings, but with an enlarged needle cylinder. A first kind of product is manufactured by means of a process according to US-A 4 043 156 which substantially consists in initially providing an elastic hem and, after said hem, a section of tubular knitting, using practically all the needles of the needle cylinder. In a subsequent step, an increasing number of needles belonging to two sets of needles are excluded from knitting; said sets of needles are angularly mutually spaced with respect to the axis of the needle cylinder so as to define, on the lateral surface of the product, two missing portions which correspond to the leg opening of the briefs to be produced. The number of needles excluded from knitting gradually increases up to a maximum value to obtain a widening of the leg openings and to obtain such a length of the portions between the two missing portions as to allow their overlapping and sewing to obtain the crotch of the briefs. The thread or threads are cut, at the beginning of the sets of needles which are not knitting, i.e. at the edges of the leg openings, by means of appropriate devices fitted to the circular knitting machine being used. The product is finished by applying an elastic tape or lace to the edge which delimits the leg openings and by sewing the overlapping ends of the portions of knitting arranged between the two missing portions so as to provide, as mentioned, the crotch of the briefs. This kind of product has the disadvantage that very often, since the thread is cut at the edges of the leg openings, broken meshes, flaws or ladders can occur starting from the edge of the leg openings during the completion of the product, since it is generally pneumatically tensioned, or during its expulsion from the machine or again during the application of the elastic tape, with the consequence of having to reject the product. A second kind of product is manufactured with a process according to US-A 4 624 115 which instead of cutting the threads at the edge of the leg openings obtains a complete tubular product, and two portions knitted with different stitches with respect to those used for the remaining part of the product are provided at the leg openings, or stitches are knitted along lines corresponding to the border of the leg openings, so as to allow the easy identification of the portions to be successively cut in order to provide the leg openings. Knitting with different stitches of the entire portions to be removed or the delimiting thereof by means of a line knitted with different stitches with respect to the remaining part of the product allows greater precision and speed in the product finishing operations. This process safely excludes the possibility of broken meshes, flaws or ladders before the finishing operations, but has the disadvantage of requiring considerable waste for each product. Also known from EP-A-0,382,968, which constitutes prior art within the meaning of Article 54(3) EPC, is a process for manufacturing a semi-finished product with circular knitting machines, in particular for producing undershirts and one-piece body garments, comprising the steps of; manufacturing a knitted body including a first section of knitting having a substantially tubular extension and defining a product axis, said knitted body having portions to be removed, and a remaining body part knitting said remaining part of said knitted body with a first number of singular threads throughout said remaining part of said knitted body; knitting said portions to be removed with a second number of singular threads, and; cutting the threads used to knit said remaining part at the edge of each of the portions to be removed; wherein said second number of singular threads is smaller than said first number of singular threads, whereby to achieve a saving in the quantity of discarded thread used for manufacturing the portions to be removed. Also known from EP-A-0,382,968 is a semi-finished product comprising a knitted body including a first section of knitting having a substantially tubular extension and defining a product axis, said knitted body having a remaining body part knitted with a first number of singular threads and portions to be removed knitted with a second number of singular threads, the second number of singular threads being smaller than said first number of singular threads, whereby to achieve a saving in the quantity of discarded thread used for manufacturing the portions to be removed. The aim of the present invention is to obviate the above-described disadvantages encountered of the known semi- finished products for manufacturing undershirts, one-piece body garments, or the like, which avoids the occurrence of broken meshes, flaws or ladders in the product during its manufacture and reduces manufacturing costs by reducing losses due to waste. Within the scope of this aim, an object of the invention is to provide a process by means of which the finishing operations are rendered extremely simple and rapid. Another object of the invention is to provide a process which allows to obtain high-quality products. According to one aspect of the invention, this aim, these objects and others which will become apparent hereinafter are achieved by a process for manufacturing a semi-finished product with circular knitting machines as defined in the appended claims 1-6. According to another aspect of the invention, the above-mentioned aim and objects are achieved by a semi-finished product as defined in the appended claims 7-10. Further characteristics and advantages of the invention will become apparent from the description of some preferred but not exclusive embodiments of the process according to the invention, illustrated only by way of non-limitative example in the accompanying drawings, wherein: figure 1 is a lateral elevation view of a product for manufacturing undershirts, manufactured with a first embodiment of the process according to the invention; figure 2 is a view of an undershirt obtained with a product of the kind illustrated in figure 1; figure 3 is a lateral elevation view of a product for manufacturing undershirts, produced with the process according to the invention in a second embodiment; figure 4 is a lateral elevation view of a product for manufacturing one-piece body garments, obtained with a third embodiment of the process according to the invention; figure 5 is a view of a one-piece body garment obtained with a product of the kind illustrated in figure 4; figure 6 is a view of an enlarged portion of the various products illustrated in the preceding figures in the region of a portion to be removed which confines with the remaining part of the product. With reference to the above described figures, the process according to the invention substantially consists in producing, with a circular knitting machine, a body of knitting having a tubular extension of the required length and in knitting the portions of the product which are to be removed by knitting stitches obtained with a number of threads smaller than the number of threads used to knit the stitches which constitute the remaining part of the product. Said remaining part of the product is conveniently knitted by using at least two threads for each stitch, whereas the portions to be removed are knitted by using a single thread, preferably the lowest-cost thread among those used for the remaining part of the product, for each stitch. The threads which are not used to knit the portions of the product to be removed are cut by the machine at the beginning of the portions to be removed. Stitches which are optically distinguishable from the contiguous stitches are advantageously knitted in regions of the product which are proximate to the portions to be removed, so as to define a guiding line for the subsequent product finishing operations, as will become apparent hereinafter. More particularly, with particular reference to figure 1, the process according to the invention comprises, for manufacturing a product 1 according to a first embodiment, a first step A during which a first substantially tubular section of knitting is produced, composed of four first portions 2 angularly spaced with respect to one another relative to the axis of the product and alternated with four second portions 3 intended to be removed. In order to manufacture said first section of knitting, the needles of the needle cylinder are divided by selection into four first sets intended to knit the first portions 2, alternated with four second sets of needles intended to knit the second portions 3. If it is required for example to knit the first portions with two threads and the second portions with a single thread, it is possible to proceed as follows. Each machine feed is equipped with two thread guides, one for each thread to be delivered, with delivery points located at mutually different elevations. The first sets of needles are raised upstream of the feed by means of known cams to such an elevation as to engage, with their tip, both of the delivered threads, whereas the needles of the second sets are raised, again in a known manner with other cams, to a lower elevation so as to engage only the thread which is delivered at the lower level. In this manner, the thread delivered by the thread guide which is arranged above remains engaged on the last needle of the first sets and remains floating behind the tip of the needles of the second sets. Said floating thread is cut by known devices which are fitted to the machine proximate to the beginning of the second portions 3, as illustrated in figure 9. In this case a 50% thread saving in terms of quantity is achieved with respect to the hypothesis of manufacturing the second portions 3 like the first portions 2, for the second portions 3. In terms of cost, the saving is even greater, since if one takes into account the fact that two threads, one of which is considerably more expensive than the other, are generally used to knit the first portions, the second portions 3 are knitted with the lower-cost thread of the two. During said first step A it is possible to select the needles, by means of selection devices commonly used in circular knitting machines for manufacturing socks and stockings, so as to increase the needles of the first sets by subtracting them from the needles of the second sets, or vice versa, so as to obtain the desired configuration for the second and first portions. After a preset number of rows it is furthermore possible, again by means of known selection devices, to divide the needles only into two first sets and two second sets to end the second portions which correspond to the neck-openings, while the knitting of the second portions, corresponding to the arm openings, continues. A second step B is performed after the first step A; during said second step, a section of knitting 4 is knitted in a known manner substantially like the first portions 3. When the product reaches the required length, knitting is ended and the product is removed from the machine. Stitches 5, arranged proximate to the second portions 3 and easily distinguishable from the others in that they define guiding lines for the finishing operation, are knitted during the first step A and shortly after the beginning of the second step B. Said stitches can be constituted by held stitches, by stitches provided with an additional thread of a different color or by floating-thread pattern stitches which can be provided, by virtue of the fact that the product is manufactured, except for the second portions 3, by using at least two threads. Ornamental patterns can be provided in a known manner during the knitting of the first portions and of the second section of knitting 5. The semi-finished product can subsequently be subjected, in a simple and rapid manner, to finishing operations by means of a known machine of the cut-and-sew type, by means of which finishing borders 6 are applied, following the guiding lines defined by the stitches 5, along the neck- and arm openings. The machine simultaneously removes the second portions 3. The shoulders of the undershirt are then obtained by sewing together the free ends of the first portions 2 in pairs, as illustrated in figure 2, and a folded hem 7 is possibly provided at the lower end of the undershirt. This last operation of hemming the lower end of the undershirt can be avoided if a second embodiment of the process according to the invention is followed; said second embodiment allows to obtain a product 1a which is already provided with a folded hem along its lower end, as illustrated in figure 3. More particularly, in this second embodiment, the knitting of the product begins from its lower end with a first step E during which the folded hem 8 with tubular extension is produced. Said hem 8 can be produced in a known manner as for the formation of the upper elastic hem of panty-hoses. If required, the hem 8 can be produced by adding an elastic thread so as to obtain an elastic folded hem. After this first step E, a second step F is performed during which a section of knitting 9 is produced, with tubular extension starting from the elastic hem 8, and a third step G is performed during which four first portions 10 are produced as continuation of the section 9 and are alternated with four second portions 11, substantially as already described with reference to the first embodiment, taking into account the fact that in this second embodiment the product is manufactured starting from the bottom. In this second embodiment, too, during the forming of the first portions 10 and of the section of knitting 9, proximate to the second portions 11, it is possible to produce stitches 12 formed substantially like the stitches 5 so as to define a guiding line for the successive finishing operations. With a third embodiment of the process according to the invention it is also possible to manufacture a product 13 for producing one-piece body garments 14, as illustrated in figures 4 and 5. With reference in particular to figure 4, in this third embodiment the process comprises a first step L and a second step M which are performed substantially like the steps A and B which have already been described with reference to the first embodiment, so as to obtain four first portions 15 alternated with four second portions 16 to be removed in a first section of knitting, as well as a second section of knitting 17 with tubular extension as continuation of the first portions 15. During the formation of the section of knitting 17, it is possible to insert, preferably in preset regions, one or more elastic threads so as to obtain for example an elastic band 18 in the region of the abdomen. This fact can be obtained by feeding the needles of the machine with an elastic thread by means of an appropriate thread guide which is activated when required. A third step N is subsequently performed during which two third portions 19 are manufactured as continuation of the second section of knitting 17 and are alternated with two fourth portions 20 intended to be removed to define the leg openings of the one-piece body garment. Said fourth portions 20 are manufactured substantially as already described for the manufacture of the second portions 3 in the first embodiment of the process, and said fourth portions 20 are advantageously knitted with a number of stitches which increases starting from the second section of knitting 17, subtracting from the stitches of the third portions 19, so as to obtain an adequate shaping of the leg openings. In this manner, the fourth portions 20 and the second portions 16 are manufactured using a smaller number of threads than the first portions 15 and the third portions 19, as already described for the first embodiment of the process. Stitches 21, optically distinguishable with respect to the contiguous stitches, as already described for the stitches 5, can be furthermore provided proximate to the fourth portions 20 and to the second portions 16. When the product reaches the required length, knitting is ended in a known manner and the product is unloaded from the machine. In this case, too, the finishing operations can be performed in a simple and rapid manner by means of a cut-and-sew machine which removes the second portions 16 and the fourth portions 20 and simultaneously applies finishing borders 22. The upper ends of the first portions 15 are sewn together in pairs to obtain the shoulder straps of the one-piece body garment, whereas buttons or the like are applied to the free ends of the fourth portions 20 for the mutual engagement thereof. During the knitting of the first portions 2, 10, 15 and in the sections of tubular knitting 4, 9, 17 in the various embodiments so far described it is possible to provide, in a known manner, a particular knitting termed "vanisé stitch", in which the stitches are knitted with two threads, one of which remains on the outer side of the knitting while the other remains on the inner side to obtain, if required, particular effects, such as for example if it is required to have wool thread on the outer side and cotton thread on the inner side of the product. In practice it has been observed that the process according to the invention fully achieves the intended aim, since it allows to manufacture products which are simple and rapid to finish with considerably reduced waste costs. The process thus conceived is susceptible to numerous modifications and variations, all of which are within the scope of the inventive concept; all the details may furthermore be replaced with technically equivalent elements. In practice, the materials employed, as well as the dimensions, may be any according to the requirements and to 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: A process for manufacturing a semi-finished product (1, 1a, 13) with circular knitting machines, in particular for producing undershirts and one-piece body garments, comprising the steps of; manufacturing a knitted body (1, 1a, 13) including a first section of knitting (A, L) having a substantially tubular extension and defining a product axis, said knitted body having portions (3, 11, 16, 20) to be removed, and a remaining body part (2, 10, 15, 19); characterized in that it comprises the steps of; knitting said remaining part (2, 10, 15, 19) of said knitted body with a first number of singular threads throughout said remaining part (2, 10, 15, 19) of said knitted body; knitting said portions (3, 11, 16, 20) to be removed with a second number of singular threads, said second number of singular threads being smaller than said first number of singular threads, cutting the excess number of threads used to knit said remaining part (2, 10, 15, 19) at the edge (5, 12, 21) of each of the portions (3, 11, 16, 20) to be removed; whereby to achieve a saving in the quantity of discarded thread used for manufacturing the portions (3, 11, 16, 20) to be removed, forming said first section of knitting (A, L) with at least four first portions (2, 10, 15) defining said remaining body part, and at least four second portions (3, 11, 16) defining said portions (3, 16) to be removed; mutually angularly spacing said four first portions (2, 10, 15) with respect to said product axis, and; alternating said four first portions (2, 10, 15) with said four second portions (3, 11, 16) to be removed. A process according to claim 1, characterized in that said four first portions (2, 10, 15) of said knitted body are knitted using at least two threads and said four second portions (3, 11, 16) to be removed are knitted using a single thread, said four second portions (3, 11, 16) each having an edge (5, 12, 21), the threads used to knit said four first portions (2, 10, 15) being cut at the edge (5, 12, 21) of each of the four second portions (3, 11, 16), whereby to achieve a 50% saving in the quantity of thread used for manufacturing the four second portions (3, 16) to be removed. A process according to claim 1 and 2, characterized in that it further comprises at least one step (B, M) of knitting a second section of knitting (4, 17) having a tubular extension, said second section (4, 17) being knitted substantially like said four first portions (2, 10, 15). Process according to claim 3, characterized in that it further comprises a step (N) of knitting two third portions (19) as continuation of said second section (17) of knitting after said step (M) of knitting a second section of knitting (4, 17), said third portions (19) being angularly mutually spaced with respect to the product axis and alternated with two fourth portions (20) to be removed, whereby to produce a one-piece body garment (13). Process according to claim 1, characterized in that it comprises the steps of; knitting a folded hem (8) having a tubular extension; manufacturing a section of knitting (9) having tubular extension starting from said folded hem (8), manufacturing said four first portions (10) as a continuation of said tubular section of knitting (9). Process according to claim 5, characterized in that said folded hem (8) is produced by adding an elastic thread. Semi-finished product for manufacturing undershirts and one-piece body garments, obtained with the process according to claims 1-6, comprising a knitted body (1, 1a, 13) including a first section of knitting (A, L) having a substantially tubular extension and defining a product axis, said knitted body having a remaining body part (2, 10, 15, 19) and portions (3, 11, 16, 20) to be removed characterized in that said remaining body part is knitted with a first number of singular threads while said portions to be removed are knitted with a second number of singular threads, the second number of singular threads being smaller than said first number of singular threads, whereby to achieve a saving in the quantity of discarded thread used for manufacturing the portions (3, 11, 16, 20) to be removed, said first section of knitting (A, L) comprising at least four first portions (2, 10, 15) defining a remaining body part, and at least four second portions (3, 11, 16) defining portions (3, 16) to be removed, said four first portions (2, 10, 15) being mutually angularly spaced with respect to said product axis and alternated with said four second portions (3, 11, 16) to be removed. Semi-finished product according to claim 7, characterized in that it further comprises at least one second section of knitting (4, 17) having a tubular extension and being knitted substantially like said four first portions (2, 10, 15). Semi-finished product according to claim 8, characterized in that it further comprises two third portions (19) defining a continuation of said second section (17) of knitting, said third portions (19) being angularly mutually spaced with respect to the product axis and alternated with two fourth portions (20) to be removed. Semi-finished product according to claim 7, characterized in that it comprises a folded hem (8) having a tubular extension and a section of knitting (9) having tubular extension starting from said folded hem (8), said four first portions (10) defining a continuation of said tubular section of knitting (9).

Inventors: LONATI FRANCESCO, LONATI, FRANCESCO
Applicants: LONATI SPA, LONATI S.P.A.
Application year: 1990
Main classification: D04B1
IPC codes: A41B9, A41C3, D04B9, D04B1