JP2004360159A - Transport belt for transporting collected fiber strand - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new-type transport belt for transporting fiber strands collected by pneumatic pressure, having an air-permeable intermediate region and air-impermeable boundary regions of which the whole areas are strengthened by heating, while conventional transport belts have such air-impermeable boundary regions that only peripheral areas thereof are strengthened by heating. <P>SOLUTION: This transport belt is so structured that the air-permeable intermediate region 25 and two of the air-impermeable boundary regions 26, 27 are formed out of a fabric comprising thermoplastic filaments, wherein the boundary regions are made to be air-impermeable through a heating process. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION The present invention relates to a transport belt for transporting pneumatically bundled fiber strands, the transport belt comprising an air-permeable intermediate region designed as a woven fabric of thermoplastic filaments, and having an edge. Includes an air impermeable boundary region treated by the heating step.

  When the drawn fiber strand is provided with a spinning twist immediately downstream of the front roller pair of the drawing apparatus, a so-called spinning triangle occurs at the nip line of the front roller pair. This occurs because the drawn fiber strands leave a width-drawing device and are twisted into a yarn having a relatively small diameter. Spun triangles include minor fibers that are not properly bonded in the twisted yarn and therefore contribute little or no tensile strength to the spun yarn. In recent years, a focusing zone has been arranged downstream of the stretching zone of the stretching apparatus, which focusing zone is also bounded by a nip line. Only downstream of it the yarn is given its spinning twist. The fibers are bundled or bundled in the focusing zone, so that the spinning triangles feared because the fiber strands are narrow when leaving the furthest downstream nip line are no longer noticeably inconvenient. The spun yarn is then more uniform, more tear-resistant and less brittle.

  Many different devices are known for the purpose of focusing fiber strands. Many of these devices are operated by air permeable transport belts, which transport the fiber strands to be bundled in a sliding fashion over the suction slits. A device of this type is disclosed, for example, in German Offenlegungsschrift 198 37 182. In this publication, a transport belt is described which comprises an air-permeable intermediate region, in particular made from a woven fabric of thermoplastic filaments, as well as air-impermeable boundary regions on both sides. The edge of this border region can be strengthened by a heating step.

  Here, in the term of this patent application, the expression “pneumatically focused” means, apart from the suction air flow, other means, such as a transport element aligned with a transversely arranged suction slit. It should be noted that

  The object of the invention is to create a new type of transport belt as described above for the pneumatic focusing of the fiber strands, in which the air-impermeable boundary zone is designed in a special way. This object is achieved according to the invention in that the air-permeable intermediate region as well as the air-impermeable boundary region are made of woven fabric, the boundary region of which is made air-impermeable by a heating process. Achieved.

  The prior art discloses a method for making the boundary area of a transport belt air-impermeable, and in the case of known transport belts only the edges of the boundary area are strengthened by a heating process, Are based entirely on woven fabrics made of thermoplastic filaments, whereby the entire boundary area is made air-impermeable by a heating process. The air-permeable woven fabric in the middle region has its border region reshaped into a kind of smooth foil. The new type of transport belts thereby provide increased dimensional stability, especially when cleaning has to be performed, sometimes for cleaning purposes. This narrow air permeable intermediate region results in reduced debris accumulation on the transport belt. This is because only the areas that are actually effective are sucked, so that no fly or debris can adhere as a result of the suction. The new type of transport belt leads to a particularly long service life.

  The transport belt is advantageously seamless in the transport direction, which is achieved by the transport belt being woven seamlessly on a circular loom in the form of a tube. A monofilament is advantageously supplied for the woven fabric, which has sufficient stability and allows a uniform suction air flow.

  The boundary area of the transport belt can be made air impermeable in various ways by a heating process. In a variant, it is provided that the boundary area is made air-impermeable by welding, for example by a correspondingly wide electrode. In a further embodiment, the boundary area can be coated with a hot melt adhesive, so that it is sufficient to coat the transport belt on only one surface, thus keeping the woven structure on the other surface .

  Indeed, transport belts having an air-permeable area 0.3 to 0.5 times the width of the transport belt itself have been demonstrated. For example, the air-permeable intermediate region can have a width of 10 mm, while the transport belt has a total size of 25 mm. The air-impermeable boundary regions are then each 7.5 mm in size.

BRIEF DESCRIPTION OF THE DRAWINGS These and further objects, features and advantages of the present invention will become more readily apparent from the following detailed description thereof, taken in conjunction with the accompanying drawings. In the drawing:
FIG. 1 is a partial cross-sectional side view of an apparatus for bundling fiber strands, including a transport belt according to the present invention;
FIG. 2 is a view of the actual focusing zone in the direction of arrow II in FIG. 1, in which the rollers shown in FIG. 1 have been omitted;
FIG. 3 is a cross-sectional view of the transport belt according to the present invention, greatly enlarged;
FIG. 4 is a section similar to FIG. 3 of a further embodiment of the transport belt according to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS An apparatus 1 for consolidating drawn but untwisted fiber strands 2 of a spinning machine, in particular of a ring spinning machine, is shown in FIGS. The device 1 is located immediately downstream of the stretching device 3 and comprises only its forward roller pair 4 and an apron roller pair 5 having a lower apron 6 and an upper apron 7 arranged in the transport direction A upstream of this forward roller pair 4. It is shown. The front roller pair 4 includes a driving front bottom cylinder 8 as well as a front pressure roller 9 flexibly pressed against it. The front roller pair 4 constitutes a front nip line 10, which forms the end of the drawing zone of the drawing device 3.

  In the stretching device 3, the sliver or roving 11 is stretched in a known manner in the transport direction A to the desired fineness. The drawing process ends at a front nip line 10 from which there is a fiber strand 2 that has been drawn but has not yet been twisted. In order to avoid the known and disadvantageous spinning triangles, the fiber strands 2 are focused immediately downstream of the forward nip line 10 of the focusing zone 12. The device 1 provided for focusing comprises an air-permeable transport belt 13, which transports the fiber strands 2 to which it is focused through a focusing zone 12. The device 1 also includes a suction channel 14, which is designed as a low pressure dominated hollow profile and extends across a plurality of spinning stations. For the purpose of guiding the transport belt 13, the suction channel 14 is designed as a sliding surface 15 on its outer contour facing the focusing zone 12.

  A suction slit 16 is provided in the slide surface 15, which is arranged slightly transverse to the direction of travel B of the transport belt 13, so that, for the fiber strands 2 to be bundled, the suction slit 16 has a fiber guiding edge. 17 inclusive. The fiber strands 2 move along this fiber guiding edge 17 at the time of consolidation, whereby the fibers located in the fiber strands 2 are bundled or bundled transversely to the direction of travel B of the transport belt 13, whereby the fibers The strand 2 is somewhat involved.

  The suction channel 14 is connected to a pressure reduction source (not shown) via a pressure reduction connection 18 located at a certain distance from the suction slit 16. If the suction channel 14 extends over a plurality of spin points, only one vacuum connection 18 needs to be provided for one suction channel 14.

  The convergence zone 12 is bounded on its downstream side by a nip roller 19, which presses the fiber strands 2 and the transport belt 13 against the sliding surface 15 while defining a delivery nip line 20, which is provided with a spinning twist to be applied. Act as a twist stop. The nip roller 19 drives the transport belt 13 and is also driven by the front pressure roller 9 via the transmission wheel 21.

  The produced yarn 22 undergoes a spinning twist downstream of the delivery nip line 20 and is supplied as a yarn 22 in the delivery direction B to a twisting element (not shown), for example a ring spindle. The delivery nip line 20 serves as a twist stop for the spinning twist, so that the spinning twist cannot return to the focusing zone 12 back.

  The transport belt 13 is pulled on the side facing away from the suction slit 16 by a pull element 23, which can be designed, for example, as a stationary bar or as a guide roller. The tension element 23 is provided here in such a way that the transport belt 13 is arranged on the front bottom cylinder 8 with little pressure. As the transport belt 13 and the front bottom cylinder 8 rotate in opposite directions at the contact line, the transport belt 13 is now cleaned of any fly sticking to it.

  As can be seen from FIG. 2, the initial region 24 of the suction slit 16 has an extension, which serves to enable the suction slit 16 to grip the fiber strand 2 traversing slightly transversely. This traversing movement serves in particular to ensure that the front pressure roller 9 has a long service life.

  With the help of FIG. 3 in a greatly enlarged view, the core of the device 1, the air permeable transport belt 13, will be described in more detail below.

  In FIG. 3, the air-permeable intermediate region 25 of the transport belt 13 is seen in a greatly enlarged dimension, this intermediate region 25 being formed of a thermoplastic filament woven material. On either side of this intermediate region 25 are air-impermeable boundary regions 26 and 27, the edges of which are indicated by the numerals 28 and 29.

  The entire transport belt 13 is initially made from a woven material, as seen in the intermediate region 25. However, the border regions 26 and 27 of the woven material are subsequently rendered air impermeable by a heating step, so that the mesh of the woven material is closed in this way. In this way, smoother border regions 26 and 27 are formed, which ensure the above-mentioned advantageous features for the transport belt 13.

  When the transport belt 13 is woven into a tube on a circular loom, its finished state can be completely seamless.

  The heating step can be performed in various ways. According to FIG. 3, the boundary areas 26 and 27 are made air-impermeable by welding with correspondingly wider electrodes. A transport belt 13 having a width B of, for example, 25 mm then has an intermediate air-permeable region 25 having a width M of, for example, 10 mm, and two air-impermeable boundary regions 26 each having a width R1 or R2 of 7.5 mm. 27.

  In the embodiment according to FIG. 4, there is the same air-permeable intermediate region 25 having a width M, which intermediate region 25 consists of woven thermoplastic monofilament. Further, it can be seen from FIG. 4 that the lower woven fabric structure extends along the entire width B of the transport belt 13. Apart from the embodiment of FIG. 3, FIG. 4 shows that the border regions 30 and 31 have been provided with a hot-melt adhesive 32 or 33 on their upper side. Thus, in this case, the pores of the woven material are not closed on the lower side, but the coating from above makes the boundary regions 32 and 33 air impermeable.

1 is a partial cross-sectional side view of an apparatus for consolidating fiber strands, including a transport belt according to the present invention. 2 is a view of the actual focusing zone in the direction of arrow II in FIG. 1 is a cross-section of a transport belt according to the invention in a greatly enlarged manner. Fig. 4 is a cross section similar to Fig. 3 of a further embodiment of the transport belt according to the invention.

Claims (6)

  A transport belt for transporting pneumatically bundled fiber strands, which comprises an air-permeable intermediate region designed as a woven fabric of thermoplastic filaments, and whose edges have an air impregnation treated by a heating step. In those containing a permeable boundary region, the air permeable intermediate region (25) as well as the air impermeable boundary regions (26, 27; 30, 31) are made from one and the same woven material, and furthermore the boundary region (26, 27; 30, 31), wherein the heating belt is made air-impermeable by a heating step.   2. The transport belt according to claim 1, wherein the transport belt is seamless in the transport direction (A).   3. A transport belt according to claim 1, wherein a monofilament is provided for the woven fabric.   4. The transport belt according to claim 1, wherein the boundary areas are air-impermeable by welding.   The transport belt according to claim 1, wherein the boundary area is covered with a hot-melt adhesive.   6. The width (M) of the air permeable area (25) is 0.3 to 0.5 times the width (B) of the transport belt (13). Transport belt according to one.

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