The present invention relates to a Raschel machine, a net and the use of the Raschel machine for producing a net.
Nets are commonly used as a material or non-airtight packing of loose goods as e.g. hay, straw, vegetables, raw cotton or other plant parts. Nets can be produced by, e.g., Raschel machines. Such Raschel machines are for example manufactured by Textilmaschinenfabrik Karl Mayer GmbH, Frankfurt, Germany.
The present invention has the object to provide an enhanced Raschel machine and a net as well as an improved method for producing a net.
According to the present invention the object is achieved by the subject matter and the method of the independent claims. Preferred further developments are described in the dependent claims.
Those skilled in the art will recognize additional features and advantages upon reading the following detailed description and viewing the accompanying drawings.
The accompanying drawings are included to provide a deeper understanding of embodiments, are incorporated in and constitute a part of this application. The drawings illustrate the main embodiments and serve, together with the description, to explain the principles of the invention. Other embodiments and numerous intended advantages will readily be appreciated upon reasonable reading of the following detailed description. The elements of the drawings are not necessarily scaled to each other. Same reference signs refer to correspondingly similar parts.
In the following detailed description, reference is made to the accompanying drawings, which constitute a part of the detailed description and in which, by way of illustrations, specific embodiments are shown in which the invention may be practiced. In this regard, a directional terminology such as “top”, “bottom”, “front”, “back”, “leading”, “trailing” etc. is used as for the orientation of the figures being described in this context. As the components of embodiments of the invention may be positioned in a variety of different orientations, the directional terminology is used for illustrative purposes and is in no way limiting. It is to be understood that other embodiments can be utilized and structural or logical changes can be made without departing from the scope defined by the claims.
The description of the embodiments is not limiting. Particularly, elements of the individual embodiments described hereinafter may be combined with elements of different embodiments.
For further explanation of components of the Raschel machine and the produced net, respectively, the terms mentioned below are used in the following:
Hereinafter, for further explanation the terms below are used:
Net or rather Fabric: thin bands, for example made from or consisting of synthetics, e.g. polyolefins as for example LLPDE (linear polyethylene with low density), LDPE (polyethylene with low density), HDPE (polyethylene with high density), PVC (polyvinyl chloride), EVA (ethylene vinyl acetate), or a similar synthetic, are processed to a net or rather a fabric.
Threads: the thin bands the net is made of.
Warp Threads: The loops interlocked to a loop compound in flow direction of the net.
Wefts: The threads with a zigzag interweaving connecting the warp threads to a net.
MD (Machine Direction): the flow direction of the net during the production or unrolling.
TD (Transversal Direction): The direction perpendicular to the flow direction or machine direction.
The Raschel machine 100 comprises a plurality of first guide needles 110 for guiding warp threads 210. The first guide needles 110 are arranged along a first direction. For example, the first direction corresponds to the transversal direction TD and is orthogonal to the flow direction of the net. The number of guide needles corresponds to the number of warp threads 210 to be created. The Raschel machine further comprises a plurality of second guide needles 150 arranged along the first direction for guiding the weft threads 220. Furthermore, the Raschel machine comprises a plurality of needles 180 arranged along the first direction for creating interlocked loops formed by threads, whereby the warp threads 210 are created.
As shown in
The first needle bar 120 with the first guide needles 110 attached therein may be configured as a metal base performing a circular motion. The position of the first guide needles 110 is fixed along the transversal direction. The second needle bar 160 the second guide needles 150 for guiding the weft threads are attached to moves back and forth along the transversal direction between two respective neighbouring first guide needles such that upon a movement of the warp threads in the machine direction a zigzag pattern is formed. For example, a weft thread is guided between two neighbouring warp threads 210 such that it connects those with each other. Thus a connection technique without any knots is enabled. The weft thread is respectively guided through the warp thread 210 at the connection points.
The second needle bar 160 the second guide needles 150 for guiding the weft threads are attached to periodically moves back and forth along the transversal direction by the space d between neighbouring first guide needles, respectively. According to an embodiment, now a space d, shown for example in
By using the Raschel machine according to the invention, now a net with a greater space of neighbouring warp threads can be produced. Accordingly, the number of warp threads is reduced with constant width. For example, as for a conventional net 52 warp threads are required to produce a net with a standard width of 123 cm, now nets with the standard width of 123 cm can be produced with considerably less warp threads. As an advantage a lower final weight of the produced net with equal strength of the used threads can be achieved. Conversely, thicker threads than usual can be used thereby facilitating the production. The strength of the used threads can be set such that the same final weight as with the conventional machine can be achieved with a reduced number of warp threads. Due to the fact that thicker threads are used, the breakage risk of the threads during the production is reduced. Accordingly, it is no longer necessary to interrupt the production due to thread breakage. As a result the throughput can be increased and the production costs can be lowered.
In dimensioning a suitable space between neighbouring guide needles 110 it has to be considered that according to the increased space the second needle bar 160 has to move laterally over an also increased distance. With constant frequency an increased distance of lateral movement may result in an excessive load on the driving motor for the second needle bar. Accordingly, the frequency can be reduced in order to avoid an overload on the motor with an increased distance of lateral movement. However, a reduction of the frequency causes a slower production of the net and thus results in a decrease of the efficiency of the Raschel machine. It was noted that an optimal throughput can be achieved with a space d of neighbouring guide needles 110 of 50.8 mm (2 inch). For example, the frequency can be halved compared to a Raschel machine with a 25.4 mm (1 inch) space of the guide needles 110. The benefits related to the increased space of the warp threads of the finished net counterbalance the disadvantages caused by halving the frequency. On the contrary, with a greater space the efficiency of the Raschel machine is impaired due to the still reduced frequency. Due to the space increased in comparison to 25.4 mm, with a smaller space the weight reduction may be too small in order to counterbalance the disadvantages caused by adapting the frequency.
The space s between neighbouring second guide needles 150 at the second needle bar may correspond to the space d between neighbouring first guide needles 110. Furthermore, the space between neighbouring needles 180 may correspond to the space d.
Thus, as also shown in
By using the Raschel machine according to the invention, now a net 200 with a greater space u of neighbouring warp threads 210 can be produced. Correspondingly, the number of warp threads 210 is reduced with constant width. If for a conventional net, for example, 52 warp threads are required to produce a net with a standard width of 123 cm, now nets with the standard width of 123 cm can be produced with less warp threads 210. For example, with a space u of neighbouring warp threads 210 of 30.48 mm (1.2 inch) nets with 42 warp threads can be produced. With a space u of neighbouring warp threads of 50.8 mm (2 inch), for the standard width of 123 cm the number of warp threads is even smaller, for example 26. As an advantage a lower final weight of the produced net can be achieved with equal strength of the threads used. Conversely, thicker threads than usual can be used, thereby facilitating the production. The strength of the used threads can be set so as to achieve the same final weight as with the conventional machine with a reduced number of warp threads. Due to the fact that thicker threads are used the breakage risk of the threads during the production is lowered. Accordingly, it is no longer required to interrupt the production due to thread breakage. As a result the throughput can be increased and the production costs can be lowered. The threads may have a thickness or rather strength greater than 90 μm or 100 μm.
For instance, the lower limit of the thickness of the thread can be determined such that it is ensured that the thread will not break during the production of the net. The lower limit of the thickness of the thread can, for example, be set to 90 μm or more. The thread may thus have a thickness of at least 90 μm or 100 μm. The predetermined weight of the net may correspond to the standard weight, e.g. 11 g/lm (linear meter). For example, the predetermined width may conform to the standard width of nets (e.g. 123 cm). For instance, the number of warp threads may be smaller than 50, in particular smaller than 45, e.g. 42 or below. According to a further embodiment the number of warp threads may be smaller than 34 or smaller than 30, e.g. from 26 to 29.
Number | Date | Country | Kind |
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10 2015 119 867.3 | Nov 2015 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2016/074610 | 10/13/2016 | WO | 00 |