Net tape for the production of sacks

Abstract: The invention refers to a net tape for the production of sacks, of the type built through the union of two net strips in plastic material, joined together along at least one edge and in correspondence of a plurality of cross strips (6) that delimit the separation area between a sack and the next one, where, in correspondence of these cross strips (6), the net tapes show only the pillar stitches (1) and the weft thread (2), while the interlacing of the weft is eliminated, so that, in correspondence of this cut area, only the threads are kept, which are arranged in a direction substantially orthogonal to the cutting direction.

Description: This invention proposes a net tape to be used for the production of sacks, especially sacks intended to contain agricultural products, vegetables and fruits, of the type which is realized through the union of two continous net tapes, and which is provided, in the tape strips that divide a sack from the next one, with an area where the interlacing of the weft is lacking, as only the pillar stitches and the weft thread are present. In this way a tape is produced that presents, in the strip between a sack and the next one, areas for a facilitated cut, that allow to improve the working of the machines for the cutting of the tape, with increased life of the blade, lesser processing times and reduced needs of maintenance. This all is due to the particular net configuration. In the field of packing, especially in the packing of agricultural products, vegetables and fruits, is is more and more frequent the use of net sacks, obtained through the interlacing of threads in plastic material, in particular threads in polyethylene. According to the known technique, as shown for example in document BE-A-533 002, these sacks are produced from two net tapes which are put one on another and paired through union along a continous line in correspondence of one edge, (ii) along a discontinous line in correspondence of the opposite edge and along cross lines with reference to the previous ones, for the whole width of the net tape, so that a plurality of sacks, placed side by side, is obtained, and these sacks are then separated by cutting the tape in correspondence of the areas where the union is made. In particular, the net that builds these tapes shows a series of small chains, arranged in the direction of the tape length, connected by a weft interlaced to the threads of the small chains. At the moment of use, the bobbin formed by a series of sacks placed side by side is automatically unwound by appropriate devices, which also provide for the cut of the paired tapes, in order to divide the sacks. The known product causes sometimes some inconveniences because of the fact that the weft threads, which are parallelly located or with a minimum inclination as regards the cut direction, must be cut by a blade or another cutting system, and this provokes complications and slackening in the processing. The inconvenient is solved with the net tape according to this invention, which is characterised by the fact that it provides, in correspondence of the union between a sack and the next one, a strip where only the pillar stitches and the weft threads are present, additionally there is a continuous area dividing said strip, in said additional continuous area the interlacing of the real weft is eliminated, that is that part of the threads that build the net and that are substantially arranged in the cut direction. In this way the cut of the tape is facilitated, the useful life of the blade of the cutting system increases, the need of maintenance intervention on the machine is reduced, especially because of jams and so on, and the rhythm of processing increases. This invention is now described in details, with reference to the enclosed figures, where: figure 1 represents a tape for the production of sacks according to the known technique; figure 2 is the view of a tape for the production of sacks according to the invention; figure 3 is the view of a sack produced from paired tapes according to the invention. With reference to figure 2, the production of sacks begins from a pairing realized by putting one on another two net tapes, which are joined during the meshing operation and then cut in order to obtain single sacks. Each of these tapes shows a plurality of threads or pillar stitches, lengthwise arranged at a certain distance one from the other, joined together through threads of weft 2, arranged in a substantially orthogonal way to the previous one and knotted to the pillar stitches. According to the known technique (see figure 1) the threads of weft 2 cover the whole length of the tape. The two tapes placed one on another are joined in correspondence of areas or stripes which are arranged cross as regards the tape and in correspondence of at least one stripe 4, arranged, on the contrary, in a lengthwise direction. The opposite edge, shown with number 5, is instead left open in order to allow the filling of the sacks with the products. The paired tapes are generally wound in bobbins and, at the moment of use, they are cut in correspondence of the areas 3, in order to divide the sasks which can, in this way, be filled and then sealed also in correspondence of edge 5. The characteristic of the invention is to provide, in correspondence of the areas 3, a strip, shown with 6, where the weft is lacking and only the pillar stitches 1 are present. This execution form allows many practical advantages. First of all, the machine cutting of the tapes in order to divide the sacks is facilitated, as the blade that performs the cut meets only the pillar stitches, which are orthogonally arranged with reference to it and which can therefore be cut more easily, speeding up the cutting operation. Besides, between a sack and the next one an area is formed where the net density is lower, so that the exact placing of the tape for the cut is easier, for instance through optical detectors or similar. At the end, this greater simplicity provides also a reduced maintenance of the machine and a lesser wear and tear of the blade. The dimensions, as well as the used materials, can change according to the use requirements, without being outside the boundaries of the protection scope of this invention.

Claims: Net tape for the production of sacks of the type which is realized through the union of two continous net strips in plastic material, joined together along at least one edge and in correspondence of a plurality of cross strips that delimit the separation area between a sack and the next one, characterized by the fact that in correspondence of these cross strips the net tapes show an area formed only by the pillar stitches and the weft thread, additionally there is a continuous area dividing said separation area, in said additional continuous area the interlacing of the weft is eliminated so that, in correspondencee of this cut area, only the threads are kept, which are arranged in a direction substantially orthogonal to the cutting direction. Net sacks produced from a tape according to claim 1.

Inventors: BERETTA PAOLO, BERETTA, PAOLO
Applicants: NOVATEX ITALIA SPA, NOVATEX ITALIA S.P.A.
Application year: 1995
Main classification: B65D30
IPC codes: B65D30, D03D1