EP1908865A2

EP1908865A2 - Device for weft insertion, especially on a device for laid scrim fabrics production

Info

Publication number: EP1908865A2
Application number: EP07466020A
Authority: EP
Inventors: Milan Stejskal; Jaroslav Fábera; Robert Klepl; Jaroslav Havlík
Original assignee: Vyzkumny Ustav Textilnich Stroju Liberec AS
Current assignee: Vyzkumny Ustav Textilnich Stroju Liberec AS
Priority date: 2006-10-05
Filing date: 2007-10-04
Publication date: 2008-04-09
Also published as: CZ2006626A3; EP1908865A3; CZ304646B6

Abstract

The invention relates to the device for weft insertion, especially on device for laid scrim fabrics production comprising means for laying of warp threads and means for guiding of warp threads through the working path to the delivery device and further to the device for bonding of the fabric, while the means for guiding of warp threads through the working path comprise at least one pair of rollers and the device for weft insertion comprises the air insertion means and it is assigned to each inlet of warp threads in between each pair of rollers (2). In the area before inlet of warp threads in between each pair of rollers (2) there is along the rollers (2) positioned a hollow body (3), in cavity of which there is performed an insertion channel (30), while the wall of the body (3) is interrupted by a longitudinal slot (31) along a whole length of the body (3) in the place against an inlet of warp threads in between the rollers (2).

Description

Technical field

The invention relates to the device for weft insertion, especially on device for laid scrim fabrics production comprising means for laying of warp threads and means for guiding of warp threads through the working path to the delivery device and further to the device for bonding of the fabric, while the means for guiding of warp threads through the working path comprise at least one pair of rollers and the device for weft insertion comprises the air insertion means and it is assigned to each inlet of warp threads in between each pair of rollers.

Background art

The laid fabrics, e.g. the "laid scrim" type are the fabrics, which in their principle are of a grid arrangement, at which individual warp threads have mutual spacing and also individual weft threads have mutual spacing. These fabrics are used to various purposes, according to character of threads or fibres used for their production, e.g. at usage of finer threads or fibres these textiles may be used as a reinforcement into the letter envelopes, if stronger (rougher) threads or fibres are used, these textiles may be applied e.g. for industrial purposes, etc. Textiles are bonded, e.g. by a glue, which after getting dry ensure fabric coherency in a given geometric arrangement similarly as for example at gauze fabrics.
There is known a production method of laid fabrics of the "laid scrim" type, at which the warp threads are separated by means of suitable means, e.g. warp combs, into a corresponding mutual spacing and they are guided to a suitable device creating space between the warp threads for positioning of the weft. Weft or a group of wefts is introduced by means of mechanical means in between the separated warp threads. In principle, immediately after the warp threads settle from both sides on the weft or wefts the fabric is being bonded by applying the glue and the weft is fixed in a given position. After then drying of the glue follows.
The disadvantage of these devices is mechanical complexity of the device for production of laid fabrics, especially the parts providing insertion of weft in between the warp threads. Another disadvantage of the present state of the art is a limited production productivity of the laid fabrics.
These disadvantages were remedied or at least reduced by solution according to CZ PV 2004 - 159 , that relates to the production method of laid fabrics, at which in between the branches of warp threads the wefts are inserted, that among each other have the required distance, after then the fabric is being bonded, e.g. by applying the glue and its drying. Upon this method the branches of warp threads are fed in between a pair of rollers, between which they are joined again, while in the place before joining the branches of warp threads between the rollers, the wefts are inserted in between the warp threads, through which a semi-product of a laid scrim fabric with wefts between the warp threads is created, which by embracement around a part of the roller circumference is delivered to delivery device for further production operations, like bonding of the fabric, etc. To improve positioning of wefts in between the warp threads, the weft is subject to a stream of auxiliary air during and/or after insertion of weft in between the branches of warp threads. To increase a productivity the warp threads before insertion of wefts are separated into branches, which are after then gradually joined together between pairs of rollers and in each place before joining together the branches of warp threads between the rollers the wefts are inserted in between the warp threads. In each place, before joining the branches together, one from series of wefts inserted on all insertion devices is inserted in between the warp threads, immediately one after another. At the same time the formed fabric by means of alternating embracement around a part of roller's surface is kept under tension and is guided to the delivery device for further processing.
CZ PV 2004 - 159 also discloses a device for production of laid fabrics comprising means for placing of warp threads and means for guiding of warp threads through the working path to the delivery device and further to the device for fabric bonding. The means for guiding the warp threads through the working path contain at least one pair of rollers, in between which are separately guided always two branches of warp threads, while in the direction of motion of warp threads to the area before inlet of warp threads between each pair of rollers there is assigned an insertion weft device, and behind each pair of rollers there is situated a tensioning device of laid fabric semi-product to a section of circumference of one from the pair of rollers, while after the last pair of rollers there is situated the delivery device of the laid fabric semi-product for further processing. The insertion weft device is at the same time formed by an air insertion device with an air insertion nozzle. Next to this, the insertion device further comprises an auxiliary weft insertion device for delivery of the weft to the space between the two branches of warp threads between the pair of rollers.
During enhancing the power of such device the defects of weft air insertion occur, which result in occurrence of defects in the produced fabric, in necessity to stop the machine and remedy the defect, etc., which reduces productivity and increases price of the produced fabric.
The goal of the invention is to remedy or at least minimise shortcomings of the present background art, especially through improvement of weft insertion by air.

The principle of invention

The goal of the invention has been reached by the device for weft insertion, especially on device for production of laid scrim fabrics whose principle consists in that in area before inlet of warp threads in between each pair of rollers there is along the rollers positioned a hollow body, in cavity of which there is performed an insertion channel, while the wall of the body is interrupted by a longitudinal slot along a whole body length in the place against an inlet of warp threads in between the rollers.
To improve the weft insertion it is advantageous, if to the body there is assigned a row of blowing nozzles, whose outlet openings of air are situated in the insertion channel.
For improvement of weft transfer in between the rollers it is advantageous if a row of air transfer nozzles is assigned to the body, while the outlet openings of air transfer nozzles are situated in the insertion channel in the direction to longitudinal slot.
According to another advantageous embodiment, to the body there is assigned a mechanical transfer device of weft from the insertion channel into an inlet of warp threads between the roller, which according to an advantageous embodiment comprises a pair of hinged levers coupled with the drive and allocated to opened ends of insertion channel, while the axis around which the hinged levers are swinging, is parallel with longitudinal axis of the insertion channel.
For improvement of weft transfer in between the rollers it is advantageous, if to the body from both opened face sides there are assigned the auxiliary transfer nozzles of weft, whose outlet opening is directed against an inlet of warp threads in between the roller.
For successful insertion it is advantageous, if an outlet of at least one air insertion nozzle of weft thread and cutting device of the weft thread is assigned to the body from one opened face side, while the weft stop with weft tensioner and weft thread cutting device are assigned to the second opened face side of the body.
According to an advantageous embodiment the body is formed by a tube, whose wall is interrupted by a longitudinal slot.
To improve insertion it is advantageous if the tube on its rear side is equipped with continuous grooves, that connect the insertion channel with external space behind the body.
According to another advantageous embodiment the body contains a flat lower body on whose rear part by its rear section there is positioned a prismatic upper body, while on upper and lower body along the whole length of body there are positioned additional slats, between whose free ends that are situated in the space of warp thread inlet in between the rollers, there is a longitudinal slot along the whole body length, while in the upper body there are positioned the blowing nozzles and air transfer nozzles.
For improvement of insertion it is advantageous, if the upper body along the whole length of the insertion channel is provided by a system of lateral continuous grooves, which connect the insertion channel with external space behind the body.

Description of the drawing

The invention is schematically represented on the drawing, where the Fig. 1 shows arrangement of the place of weft insertion, the Fig. 2 one exemplary embodiment of the body with insertion channel, the Fig. 3 arrangement of picking mechanism on one end of the body with insertion channel, the Fig. 4 arrangement of picking mechanism on the second end of the body with the insertion channel and the Fig. 5 a perspective view on embodiment of the body with the insertion channel from the Fig. 2.

Examples of embodiment

Production method of laid fabrics and the device for production of laid fabrics are sufficiently explained in CZ PV 2004 - 159 , therefore here only those parts of the method and device, which relate to this invention, will be described or repeated.
The method and device according to CZ PV 2004 - 159 consists in that, the warp threads are separated into branches, which are independently brought in between a pair of rollers, between which they join together again and further as joined they are delivered by embracement around a section of circumference of one of the rollers to further processing. In the place before joining of both branches between the rollers the wefts are inserted between the warp threads so that in between the rollers the fabric with the wefts inserted between the warp threads is being fed, and by embracement around a section of circumference of one of the rollers the wefts are held in the required position between the warp threads until bonding of the fabric, e.g. by fixing by means of the glue or heat between a pair of warmed rollers, etc. Weft insertion in between the branches of warp threads before their entry in between the rollers may be supported by usage of auxiliary media acting in principle crosswise to the motion direction of wefts or askew in the motion direction of wefts and improving the positioning of wefts between the warp threads, e.g. similarly as the known blowing nozzles at the weaving machines.
The Fig. 1 represents a schematic arrangement of a device for weft insertion between the warp threads upon production of laid fabric, which contains a pair distanced one from another separation rollers 1, through which always one branch a, b of the warp threads is guided. Both branches a, b of the warp threads are guided between the rollers 2, which rotate in direction of the arrows x y. In the space before entry of warp threads in between the rollers 2 there is situated the insertion device of weft by acting of the insertion air.
The weft insertion device comprises the insertion channel 30, which is performed in cavity of the body 3, which is arranged along the rollers 2 in the space before entry of warp threads in between the rollers 2. The wall of the body 3 in the place against entry of warp threads in between the rollers 2 along a whole length of the body 3 is interrupted by a longitudinal slot 31, through which a weft outlet from the insertion channel 30 is performed into a space between the branches a, b of warp threads on the rollers 2.
The body 3 is from both face sides opened into the insertion channel 30, while to one opened face side there is assigned an outlet of not represented at least one air insertion nozzle 300 of the weft thread and here is also situated the cutting device 301 of the weft thread and an auxiliary transfer nozzle 302 for transfer of weft end being outside the insertion channel 30 into the space between the branches a, b of the warp threads between the rollers 2. To the second opened face side of the body 3 there are assigned the weft stop 303 with weft tensioner, the cutting device 304 of the weft thread and a second auxiliary transfer nozzle 305 for transfer of weft end being outside the insertion channel 30 into the space between the branches a, b of the warp threads between the rollers 2.
To the body 3 there are assigned the blowing nozzles 32 to support weft insertion through the whole length of the insertion channel 30, while the outlet openings of an air streaming from the blowing nozzles 32 are situated in the insertion channel 30 and they are for example by means of some of the known manners directed in the direction of weft insertion and/or askew to the direction of weft insertion.
To the body 3 in the represented example of embodiment there are assigned the air transfer nozzles 33 of the weft for weft transfer from the insertion channel 30 through a longitudinal slot 31 into the space between the branches a, b of the warp threads between the rollers 2, while the outlet openings of air transfer nozzles 33 are situated in the insertion channel 30 towards the longitudinal slot 31.
In the not represented example of embodiment to the body 3 there is assigned a mechanical transfer device of weft from the insertion channel 30 through the longitudinal slot 31 into the space between the branches a, b of the warp threads between the rollers 2. Mechanical transfer device as an example comprises a pair of hinged levers coupled with the drive and assigned to opened ends of the insertion channel 30, while the axis, around which the hinged levers are swinging, is parallel with a longitudinal axis of the insertion channel 30.
In the represented example of embodiment the body 3 is formed by a flat lower body 34, on whose rear section 341 with its rear section 351 there is mounted a prismatic upper body 35. On the upper and lower body 35, 34 along a whole length of the body 3 there are positioned additional slats 36, between whose free ends, which are situated in the space of entry of the warp threads in between the rollers 2, along the whole length of the body 3 there is a space creating a longitudinal slot 31. In this way, the insertion channel 30 is delimited by additional slats 36, by the upper body 35 and the lower body 34. In the upper body 35 there are mounted the blowing nozzles 32 and the air transfer nozzles 33. To improve parameters of weft insertion by air the upper body 35 , along its whole length, is provided by a system of lateral continuous grooves 350, which connect the insertion channel 30 with an external space behind the body 3.
In the not represented example of embodiment the body 3 is performed in another suitable manner, e.g. it is formed of a tube of a suitable size and shape of cross-section of an inner space, which forms the insertion channel 30. The wall of the tube in an appropriate place is interrupted to create a longitudinal slot 31. To the tube there are assigned the air nozzles and further equipment for insertion of the weft into the insertion channel 30. Also the tube may be provided with continuous grooves to improve weft insertion by air.
The invention is not limited only to the expressly described and represented embodiments, but within the scope of common professional skills it is possible to modify the described and represented embodiments according to actual requirements.

Claims

The device for weft insertion, especially on device for production of laid fabrics comprising means for laying of warp threads and means for guiding of warp threads through the working path to the delivery device and further to the device for bonding of the fabric, while the means for guiding of warp threads through the working path comprise at least one pair of rollers and the device for weft insertion comprises the air insertion means and it is assigned to each inlet of warp threads in between each pair of rollers, characterised by that in the area before inlet of warp threads in between each pair of rollers (2) there is along the rollers (2) positioned a hollow body (3), in cavity of which there is performed an insertion channel (30), while the wall of the body (3) is interrupted by a longitudinal slot (31) along a whole length of the body (3) in the place against an inlet of warp threads in between the rollers (2).
The device according to the claim 1, characterised by that, to the body (3) there is assigned a row of blowing nozzles (32), whose outlet openings of air are situated in the insertion channel (30).
The device according to any of the claims 1 or 2, characterised by that to the body (3) there is assigned a row of air transfer nozzles (33), while the outlet openings of air transfer nozzles (33) are situated in the insertion channel (30) in the direction to longitudinal slot (31).
The device according to any of the claims 1 to 3, characterised by that to the body (3) from both opened face sides there are assigned auxiliary transfer nozzles (302, 305) of weft, whose outlet opening is directed against an inlet of warp threads in between the rollers (2).
The device according to any of the claims 1 or 2, characterised by that to the body (3) there is assigned a mechanical transfer device of weft from the insertion channel into an inlet of warp threads in between the rollers (2).
The device according to the claim 5, characterised by that the mechanical transfer device of weft comprises a pair of hinged levers coupled with the drive and assigned to opened ends of the insertion channel (30), while the axis, around which the hinged levers are swinging is parallel with longitudinal axis of the insertion channel (30).
The device according to any of the claims 1 to 6, characterised by that to the body (3) from one opened face side there is assigned an outlet of at least one air insertion nozzle (300) of weft thread and the cutting device (301) of weft thread, while to the second opened face side of the body (3) there are assigned the weft stop (303) with the weft tensioner and the cutting device (304) of weft thread.
The device according to any of the claims 1 to 7, characterised by that the body (3) is formed by a tube, whose wall on the side at inlet of the warp threads in between the rollers (2) is interrupted by a longitudinal slot (31).
The device according to the claim 8, characterised by that the tube on its rear side is equipped with continuous grooves, that connect the insertion channel (30) with external space behind the body (3).
The device according to any of the claims 1 to 7, characterised by that the body (3) contains a flat lower body (34), on whose rear part (341) by its rear section (351) there is positioned a prismatic upper body (35), while on upper and lower body (35, 34) along the whole length of body (3) there are positioned additional slats (36), between whose free ends that are situated in the space of warp thread inlet in between the rollers (2), along the whole body length (3) there is a longitudinal slot (31), while in the upper body (35) there are positioned the blowing nozzles (32) and air transfer nozzles (33).
The device according to the claim 10, characterised by that the upper body (35) along the whole length of the insertion channel (30) is provided with a system of lateral continuous grooves (350), which connect the insertion channel (30) with external space behind the body (3).