Textiles: knitting – United needle machines – Straight
Reexamination Certificate
1999-07-07
2001-04-03
Worrell, Danny (Department: 3741)
Textiles: knitting
United needle machines
Straight
C066S203000, C066S191000, C066S195000, C066S194000
Reexamination Certificate
active
06209359
ABSTRACT:
TECHNOLOGICAL BACKGROUND OF THE INVENTION
Auto-gripping straps are an extremely widespread application in the manufacturing of clothing, or generally, in domestic applications.
Said straps consist of two parts. A first part comprising of the loops which are destined to cooperate, through a redundant hooking link, with a second part, for instance hooks, string-like elements with an over-sized head, analogue elements, etc.
For evident, cost-based reasons, particularly important when single-use articles are to be mass-produced, notably diapers, one has to research economical manufacturing processes.
An economical process known for garments, for instance in the form of bands, of the part comprising the loops of this type of strap, is the manufacturing of a laminate consisting of a chained or weft material with loops counter-glued on a support.
However, this process is relatively complex, in so far as it necessitates a separate preparation for each of the two external layers of the laminate, then a technically complex gluing operation.
The present invention therefore relates to the manufacturing process of a loop cloth, the steps of which are fewer and therefore simpler than those intervening in the manufacturing of a laminate.
A process of this type is put to use on a knitting machine, modified to produce a loop cloth, described in the American U.S. Pat. No. 4,003,222, published on Jan. 18, 1977.
The modification consists of the transformation of the fixed lancets system in a mobile system. The lateral movement of the lancets allows for high-speed hook manufacturing, with a very high degree of dimensional stability, over a knit framework.
The manufacturer of this machine, the German company LIBA MASCHINENFABRIK, had solved the problem of optimal control of the string in an original and efficient fashion.
It is also with a view to increase the speed and quality of production guides can be used on this machine type, as for instance on the knitting machine of the aforementioned company, described in the European patent application EP 511580, published on Nov. 4, 1992.
However, regardless of the quality of the product manufactured, the problems that arise from the mechanically fragile and dimensionally unstable structure of a knitted material remain.
Another known process consists of inserting loops in a sheet. The material this sheet is made of could feature all required characteristics, both in terms of resistance and flexibility.
Textile machinery that can operate this process is available on the market in different forms.
The main machine is manufactured by the company MALIMO. It produces stitched loops from a simple or double knit armor. The machine includes a gang of fixed lancets.
There also exist a few machines using hooks, which produce loops either as frames or stitched, by insertion on a sheet. In this case, the lancets are still fixed.
The fact that loops manufactured through these processes are flat on the surface of their support is a negative consequence of the fixedness of lancets. The ease of strapping complementary elements of the strap is therefore naturally decreased compared to the expected result of using perfectly straight loops.
The conclusion derived from the above review of the existing state of the process is that manufacturing processes that knit loops on a sheet are known, but there exist no simple and economical process that provides full satisfaction today. Particularly, loop cloth manufactured by those processes features neither the dimensional stability nor the structural characteristics required for heavy-duty applications, notably diapers.
GENERAL DESCRIPTION OF THE INVENTION
The present invention relates to a manufacturing process of knitting loops on a support, for instance a sheet, which will remedy inconveniences featured by prior manufacturing processes.
Its precise purpose is a loop manufacturing process making use of, as means themselves known, a transversal gang of needles, each comprising a closing string and a hook, and at least one transversal gang of small guides. These gangs are located on either side of said sheet, in a conventional fashion. A transversal gang of longitudinal lancets is also used.
In this process, the sheet is continually fed from the top to the bottom of a knitting machine, the above gangs of which are its main components, notably to obtain a loop material constituting one of the two cooperating parts of an auto-gripping strap.
In a known fashion, the longitudinal loop columns are produced on one side of the sheet with driving the knitting strings from the small strainers onto the corresponding lancets, on the one side. On the other side, the loops are restrained on the sheet with driving the knitting strings back on the other side of the sheet.
Following a known manufacturing process of loop-knitting onto a sheet, after the production of at least a first loop on a lancet, and before and also for the formation of a second loop on this lancet, the lancet holding the first loop moves transversally in one direction and by a predetermined distance. After the formation of the second loop on this lancet, again the lancet holding the first and second loop moves transversally by the same distance but in the opposite direction, before and for the formation of a third loop on this lancet. The cycle of transversal movement of the lancet in one direction and then the other is repeated every two loops.
According to this process, the lancets are located against the side of the sheet that guides. A variation can be broken down into four cyclically repeated steps:
A first step during which, successively, the needles having moved from the lower position to the back position, the seam having been completed by a mechanical process known as felling, the sheet advances by one stitch, the lancets move transversally and the small guides accomplish a first lateral movement in the opposite direction behind the needles,
A second step during which, successively, the needles move towards the small strainers, punch through the sheet, move through the comb of lancets, then the small guides accomplish a first longitudinal movement towards the top, followed by a second lateral movement of a step towards the initial direction,
A third step during which, successively, the needles begin their return to the back position, then the small guides move under the needles by a second longitudinal movement towards the bottom, the second longitudinal movement having for effect to snare each of the strings in the hook. The closing strings then begin to close the needles,
A fourth step during which, successively, the closing strings having closed the needles, those carry on their return to the back position until the moment when, the strings moving through the sheet and forming the loops on this first side, the felling is completed. The needles carry on towards the lower position and finally the closing strings open said needles.
According to this process, one obtains loops on one side of the material, alternately and transversally oriented to the left and to the right. On the other side of the material (to the bottom, on the side of the needles), one obtains stitches, which maintain the loops in a more-or-less vertical position. However, from the totality of the string used, a major part (up to 50%) is used to form the stitches and the remainder is used for the loops.
Following the invention, the role of the stitches and loops is inverted. Once the cloth is obtained from intermediary loops on the upper side and “knitted” stitches on the under side, the process according to the invention includes a further step during which stitches are pulled downwards, so that the string on the upper side that forms the intermediary loop is pressed against the material and the stitching strings are taken away from the material to form a double loop.
Many more loops are therefore obtained for an identical quantity of string and less string is used for the simple task of support. This is obtained by a process according to the invention, the steps of which include:
to realize long
Adams, Schwartz & Evans P.A.
APLIX, a limited company
Worrell Danny
LandOfFree
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