Patent Application
20130333794
The invention relates to a device for manufacturing a fabric and to a fabric.
Such devices for fabric manufacture are known as conventional looms. Such a loom comprises a plurality of heddle shafts driven in opposite directions, wherein a plurality of heddles are arranged beside one another at the heddle shafts, with the warp threads running off the warp beam being guided through the heddles. The shafts run in opposite directions to one another so that a shed is raised by the heddles with the warp threads guided therein on such an oppositely directed movement of the shafts. A weft thread is guided through this raised shed, for example by means of rapiers or also by means of air. Such machines are then called either rapier machines or airjet machines. After the introduction of each pick, the weft thread is beaten up to the fabric by the reed arranged at the loom.
Such a known loom requires a substantial drive force which is substantially due to the up and down movement of the heddle shafts with the heddles arranged thereon. Drive powers of 70 kW and more are sometimes required. It is furthermore disadvantageous that only a customary fabric (linen weave) can be manufactured using such conventional weaving looms.
A loom is known from DE 100 03 919 A1 in which the weft thread is bound in the fabric by a half-cross leno weave. For this purpose, the loom has a plurality of leno weave apparatus which are arranged next to one another, but which are driven centrally by one drive.
GB 2124664 A shows a similar loom. A plurality of disks are provided there which are arranged next to one another, mesh with one another and are driven centrally by a drive disk. The disks each have two openings for the leno threads which are disposed diagonally opposite one another.
DE 100 34 355 A1 describes leno selvage formation apparatus arranged in pairs within the fabric on a loom so that each fabric has a leno selvage after cutting the fabric between the selvage formation apparatus.
The underlying object of the invention is to provide a device for manufacturing a fabric which has a comparatively small drive power and which furthermore creates the opportunity to manufacture a fabric in which a pattern can be woven. The continuous length of fabric should furthermore have a strength or tension which is as uniform as possible over a substantial portion of its width. It is the case in the manufacture of fabrics on customary looms that the strength or tension of the fabric reduces toward the edge of the fabric. The distribution of the tension over the width of a continuous length of fabric is also called inhomogeneous warp tension, i.e. the distribution of the tension drops continuously in arc form from a crown line at the center of the continuous length of fabric toward the edge of the fabric without the tension at the edge becoming zero. A continuous length of fabric with a very pronounced arcuate distribution can in particular not be used in certain technical applications. This applies e.g. to technical fabrics made from glass filaments which are also used as reinforcement fabrics, e.g. in concrete buildings. Such a fabric in accordance with the prior art also does not lie taut on the beam of the fabric take-off in the edge region, which can result in creasing in the edge region. Creased fabrics can only be further processed with limitations.
In accordance with the invention, a device in accordance with the wording of claim 1 is proposed to achieve the object. Such a device for manufacturing a fabric comprises a plurality of apparatus for manufacturing a leno weave (leno weave apparatus) which are arranged next to one another on at least one carrier and which work automatically. Two leno threads are supplied to each leno weave apparatus, with the device for manufacturing the fabric having at least one weft thread picking device, with the weft thread being introduced into the shed of leno threads raised by a plurality of leno weave apparatus. The weft thread is bound using two respective leno threads over the width of the fabric at a plurality of points behind the weft thread by a plurality of leno weave apparatus. To achieve a homogenized warp tension distribution over the width of the fabric, at least one of the leno weave apparatus arranged in the edge region of the fabric carries out a higher number of interlacings than at least one leno weave apparatus arranged in the central region of the fabric. In the following, the two threads for the binding of the weft thread will be called leno threads. They are often also called ground or standard threads.
Alternatively, to achieve a homogenized warp tension distribution, the lowering of the shed can be carried out by the leno weave apparatus at different times over the width of the fabric. A homogenized warp tension distribution can also be achieved by a combination of a plurality of interlacings having a lowering of the shed differing in time.
Provision is in particular made with respect to the binding of the weft thread, i.e. the lowering of the shed, at different times that the lowering of the shed by the leno weave apparatus takes place earlier in the edge region than in the central region to restrict the possibility of movement of the weft thread. The weft thread in this respect has more time to yield toward the center of the fabric, which thus results in a homogenized distribution of tension over the width of the fabric.
The device for supplying the lend threads can be a warp beam or also a plurality of reels loaded with threads. In this respect, working automatically means that every leno weave apparatus has its own drive. This is in contrast to e.g. heddles which are externally driven by the shafts.
The drive power of such individual leno weave apparatus is at around 10 watts. Even on the arrangement of 30 or 40 such leno weave apparatus next to one another on a carrier, only a fraction of the drive power is required which a conventional loom having heddle shafts moving up and down in opposite directions requires. The reason for this is essentially that the moved mass of the individual leno weave apparatus is substantially lower with respect to the moved mass in a customary loom having heddle shafts and the heddles suspended thereon. There is also the option due to the lower moved masses and the possibility of higher speeds accompanying this of allowing such leno weave apparatus to bind multiple times between the picking of two weft threads. It is possible with such leno fabrics or also multiple leno fabrics, i.e. fabrics in which the two leno threads are interlaced with one another a multiple of times between the individual weft threads, to produce a considerably higher resistance to displacement and in this respect also a considerably open textile structure. Areas of use for such open fabrics result e.g. in textile-reinforced concrete, as reinforced plaster or e.g. as agricultural fabrics. Lens fabrics have been manufactured using conventional leno harnesses up to now, which, however, only allows very low production speeds of only around 200 picks a minute. Even if the low production speed is ignored for a moment, only half-cross leno weaves can also be manufactured using these conventional leno harnesses. In a half-cross leno weave, the leno threads are only twisted once between the weft threads. Such a weave is admittedly also characterized by a certain strength which also allows so-called open fabrics to be manufactured, i.e. fabrics which present as porous textile fabrics. The displacement strength is, however, as already explained, nevertheless not sufficient for some application purposes. Open fabrics which have extreme displaceability strength and which satisfy the highest mechanical demands can be manufactured by the use of such leno weave apparatus, as previously described, and here in particular in the form of so-called propeller lenos.
Such a propeller leno is characterized by an electric motor which comprises a rotor, with the rotor comprising two vanes disposed diagonally opposite one another for forming a propeller, with the vanes each having an eyelet for guiding the two leno threads at their end sides. It has been found that in particular glass yarns can also be processed using such leno weave apparatus without there being the risk of the breaking of such yarns in processing.
A further advantage of the use of the lens weave apparatus in accordance with the invention is that the strength of the textile can be set over the width of the continuous lengths of fabric. This applies in that the number of interlacings of the leno threads can be selected freely to a certain extent after each weft thread yield and as a consequence thereof the strength of the fabric can also be set. It has been stated with respect to the prior art that the tension values and strength values of a conventional fabric reduce continuously from the center toward the edge. The distribution of the tensions values and strength values over the width is accordingly arcuate, as already stated. The tension distribution can be configured as constant thanks to the use of the leno weave apparatus in accordance with the invention; i.e. the continuous length of fabric has an equal strength and tension over a larger width. It follows from this that a higher strength can e.g. be achieved in the edge region either in that the number of interlacings of the leno threads is increased toward the edge or in that the number of interlacings of the leno threads is reduced in the center of the fabric in order admittedly thus to reduce the strength level and tension level, but to achieve almost equal values over a larger width. Alternatively or additionally, the binding over the width of the fabric can also be carried out by individual leno weave apparatus at different times, as has already been described.
A particularly advantageous embodiment of the device in accordance with the invention for manufacturing a fabric is characterized in that the apparatus has a second carrier extending in parallel to the first carrier, with the two carriers standing approximately in a horizontal plane with respect to one another, with a plurality of the leno weave apparatus being arranged staggered on the first front carrier, with the second carrier likewise having a plurality of leno weave apparatus arranged next to one another, with the leno weave apparatus on the second carrier being arranged in the gaps between the leno weave apparatus on the first carrier. The leno weave apparatus have a specific diameter. The diameter is substantially determined by the size of the motor, and in particular also by the radial extent of the propeller.
Since the individual leno weave apparatus are arranged staggered next to one another on the carrier, there is the possibility of arranging a second carrier behind it in the horizontal plane of the first carrier to arrange the leno weave apparatus on this carrier exactly in the gap between the leno weave apparatus of the first carrier on the second carrier. This means that the spacing of the weave rows can thus be reduced between one another with the consequence that the porosity of the fabric can be set very amply.
It has already been pointed out that the leno weave apparatus has a device for the rotatable acceptance of leno threads. Provision is made in accordance with a particularly advantageous feature that the devices for receiving the leno threads are configured in the leno weave apparatus on the second carrier such that the shed raised by them is larger than the shed of the leno weave apparatus on the first carrier. This means that the propeller is larger with respect to a propeller leno. This in light of the following:
The leno weave apparatus on the second carrier are located spaced toward the rear with respect to the leno weave apparatus on the first carrier. This has the consequence that the shed raised by the leno weave apparatus on the second carrier has a lower height in direct proximity to the fabric edge than the shed which is formed by the leno weave apparatus on the first carrier. If provision is now made that the shed formed by the leno weave apparatus on the second carrier is larger than the shed raised by the leno weave apparatus on the first carrier, the different shed size due to the rows of leno weave apparatus arranged offset behind one another can hereby be compensated. It is again pointed out in this connection that in particular propeller lenos should be used, with it being advantageous that with such a propeller leno only the propeller has to be increased in size to be able to provide a large shed.
In accordance with a further feature of the invention, the apparatus for manufacturing a fabric includes a reed which serves to beat up the weft thread to the fabric.
A fabric manufactured using an apparatus such as has been described above is likewise a subject of the invention. The fabric is characterized in this respect in that a weft thread is bound using two respective leno threads over the width of the fabric at a plurality of points behind the weft thread (40) by a plurality of leno weave apparatus, that is before the reed, by a plurality of leno weave apparatus using a respective two leno threads, with the two leno threads each received by a leno weave apparatus being connected to one another by a different number of interlacings by the leno weave apparatus. This has the consequence that every leno weave apparatus which receives a leno thread pair can bind the weft thread with a different number of interlacings over the width of the fabric. Provision can thus e.g. be made, as was also already explained at another point, to increase the number of the interlacings toward the edge region to achieve a constant tension distribution over the width of the fabric. This means that a homogenization of the tension distribution dropping in arcuate manner takes place toward the sides of a fabric in this respect. This is done in that a tension distribution substantially constant over the width can be achieved in the edge region by an increased number of interlacings of the leno threads with one another with respect to the central region of a fabric. The number of interlacings can in this respect be freely combined between half an interlacing, i.e. an interlacing of the two leno threads by 180°, with interlacings which also amount to a multiple of 360°.
A fabric is also a subject matter in which the binding of the weft thread over the width of the fabric is carried out at different times for homogenizing the arcuate tension distribution. The binding of the weft thread, thus the lowering of the shed, can in particular take place earlier in the edge region than in the central region of the fabric. The edge region of the fabric comprises around 20%-30% of the fabric width.
The invention will be described in more detail below by way of example with reference to the drawings.
The two leno threads 2 and 3 are located on the warp beam. It is, however, also conceivable to provide reels for the reception of the leno threads. The leno threads 2 and 3 are supplied to the leno eave apparatus marked by 10. A plurality of such leno weave apparatus 10 are located arranged next to one another over the width of the fabric on a carrier 12. A second carrier 15 having leno weave apparatus 10 likewise arranged thereon is located at the same height in parallel to this carrier 12. The leno weave apparatus 10 on the two carriers have the same design in principle. There is a spacing between the leno weave apparatus 10 arranged on the carrier 12, with the spacing being such that the leno web apparatus 10 arranged on the carrier 15 are likewise able to form a shed in the gap between two respective leno weave apparatus 10 on the carrier 12. This means that space must also remain for the rotation of the propeller. It has already been pointed out that the leno weave apparatus arranged on the carrier 15 can have a propeller which has a greater radial extent than the propeller of the leno weave apparatus 10 on the carrier 12. This is against the background that the carrier 15 has a greater spacing from the fabric edge which is marked by the arrow 20. This means that the shed would be correspondingly smaller directly at the fabric edge than the shed which is raised by the leno weave apparatus 10 on the carrier 12. This can be compensated by a larger propeller. The apparatus furthermore has a reed 30 which, as is known, serves to beat up the weft thread 40 picked into the shed. The finished fabric is received by the fabric take-off beam 60.
The configuration of the leno weave apparatus 10 as a propeller leno results in detail from
| Number | Date | Country | Kind |
|---|---|---|---|
| DE 10 2012 009 42 | May 2012 | DE | national |
