Title of Invention

A METHOD FOR IMPROVING THE INSERTION BEHAVIOUR OF A WEFT YARN

Abstract

, A method for improving the insertion behaviour of a weft yarn, especially a synthetic filament weft yarn, during the production of fabric on jet looms, according to which during a first predetermined angle of rotation range of the main shaft of the loom the weft yarn is inserted from a main nozzle into a shed formed by warp threads and is received on the withdrawal side of the shed during second predetermined angle of rotation range of the main shaft of the loom, thereupon the weft yarn remaining in the main nozzle is gripped in the weft insertion direction downstream of the injector of the main nozzle by a gripping device and the length of weft yam inserted into the shed is interlaced by closing the shed and subsequently the weft yam is subjected to an intermingling process along the length remaining between the gripping device and the insertion-side interlacing throughout a predetermined third angle of rotation range of the main shaft of the loom.

Full Text

A method for improving the insertion behaviour of a weft yarn, especially a synthetic filament weft yarn, during the production of fabric on jet looms, especially air jet looms, and a jet loom for carrying out the method. The invention relates to a method for improving the insertion behaviour of a weft yam, especially a synthetic filament weft yarn, during the production of fabric on jet looms, especially air jet looms, in accordance with the features of the preamble to claim 1. The invention relates furthermore to a jet loom, especially an air jet loom, for carrying out the method with pattern-controlled insertion of the weft yam. A method in public use by the applicant for intermingling unmingled or only partially mingled weft yams, especially synthetic filament weft yarns, and a loom for carrying out the method comprise the subject matter of the German patent specification registered under file reference 102 09 278.8. According to the subject matter of the above-mentioned patent application, a length section of a weft yarn extending from the inlet of the main nozzle to the outlet of the mixing tube of the main nozzle is subjected at its end region, that is, close to the outlet of the mixing tube of the main nozzle, to an intermingling operation. The effect of this measure is that right into the injector of the main nozzle and partly as far as the prewinder, the weft yam is more or less unintentionally intermingled. The intermingling is partially loosened again by what is known as holding air that is directed necessarily onto the weft yarn during a wafting time of the weft yam in the region of the main nozzle. The overlap of these processes (holding of the weft yam with holding air and intermingling by means of an air stream), leads on the one hand, in particular in yams susceptible of tearing, to undesirable detachment and tearing of filaments. On the other hand, the holding air and the intermingling process modify the structure of the weft yarn over a length that, after insertion of the weft yam, becomes part of the fabric. The quality of the fabric produced is consequently substantially impaired. Against this background, it is an object of the invention, while improving the insertion behaviour of a weft yam, to limit modification of the weft yam resulting from a known intermingling process in the mixing tube of a main nozzle, in particular in respect of a unfavourable aiteraticn of the weft yam structure, to a length of weft yam that will belong to subsequent weft yarn waste, and to dispense with the operation of holding the weft yam with holding air.. In accordance with the inventive method, the object is essentially achieved in that a length of the weft yam remaining in the main nozzle after the insertion of a weft yam into a shed is-gripped by a gripping device at a point in the weft insertion direction downstream of the injector of the main nozzle, the length of weft yam inserted into the shed is then interlaced by closing the shed, and the length of weft yam remaining between the gripping device and the insertion-side interlacing is subjected throughout a predetermined angle of rotation range of the main shaft of the loom to an intermingling process. The advantage is gained that in the case of a intermingled weft yarn the intermingling is not loosened again by the holding air, that holding air can be completely omitted and hence the consumption of compressed air is reduced and the energy balance is improved. Furthermore, the disadvantages associated with the known solution are avoided. In an embodiment of the method according to the invention, the intermingling process commences before the inserted weft yam is severed from the weft yam held in readiness, namely at about 320° of the angle of rotation of the main shaft of the loom. The fact must also be mentioned that the intermingling process is carried out in the mixing tube of the main nozzle, as is known from the application of the method. The method according to the invention is carried out on a jet loom., especially an air jet loom with pattern-controlled insertion of the weft yarn. As claimed in claim 6, the air jet loom comprises at least one main nozzle with an injector and a mixing tube, in the weft insertion direction downstream of the injector a gripping device arranged in the mixing tube to grip the weft yarn, in the weft insertion direction downstream of the gripping device an intermingling device arranged in the mixing tube or at the output side on the mixing tube, and means for forming a shed and for bringing about a closure of the shed. In accordance with the invention., a gripping device located in particular in the mixing tube of the main nozzle can be a central closing means in the form of a pneumatic or hydraulic muscle. A gripping device can moreover be formed by a pneumatic or hydraulic muscle and, as gripping means, two lamellar elements integrated in the muscle, which consist of elastic material and together with the muscle form the gripping device. Moreover, two lamellar elements consisting of preferably elastic material can be provided as gripping device, the position of at least one of the two lamellar elements being adjustable with respect to the other lamellar element by controllable means. At least one of the lamellar elements can in this case be in the form of a piezo element, or an electromagnetic means suppliable with power can be associated with at least one of the lamellar elements. The invention is explained in detail below with reference to an exemplary embodiment The drawing shows a main nozzle 1 with a gripping device 6 for the weft yam 7; the gripping device is inserted downstream of the injector 2 of the main nozzle 1, between a first mixing tube portion 4 and a second mixing tube portion 5 of a mixing tube 3. The gripping device 6 is here in the form of a pneumatic muscle 8. The pneumatic muscle 8 is enclosed by a pressurisabie chamber 9 of a housing 10, From a pneumatic pressure source 14, compressed air is conveyed to the chamber 9 via an electricaily-activatable magnetic directional control valve 11 and via the pressure lines 12,13. The muscle 8 constricts the weft yarn approximately along the longitudinal centre line of the mixing tube 3, The weft yam 7 is held gripped for - a predetermined period. By switching the magnetic directional control vaive 11 from position A to position B, the muscle 8 relaxes, the result being that the weft yam 7 is released for insertion, as indicated by the direction arrow 15, into a shed, not shown. Downstream of the gripping device 6, an intermingling device 16 known perse is arranged on the second mixing tube portion 5. Transversely to the longitudinal centre line of the mixing tube 3, the intermingling device 16 has a compressed air connection 17,. which opens into a transverse bore 18 of the mixing tube portion 5. An electrically-controlled magnetic directional control vaive 19 connects the intermingling device 16 via the pressure lines 20,21 to a pneumatic pressure source 22, By switching the magnetic directional control vaive 19 from position A into position B, the intermingling process is interrupted, Claims 1. A method for improving the insertion behaviour of a weft yam, especially a synthetic filament weft yam., during the production of fabric on jet looms, according to which during a first predetermined angle of rotation range of the main shaft of the loom the weft yam is inserted from a main nozzle into a shed formed by warp threads and is received on the withdrawal side of the shed during second predetermined angle of rotation range of the main shaft of the loom, thereupon the weft yarn remaining in the main nozzle is gripped in the weft insertion direction downstream of the injector of the main nozzle by a gripping device and the length of weft yam inserted into the shed is interlaced by closing the shed and subsequently the weft yarn is subjected to an intermingling process along the length remaining between the gripping device and the insertion-side interlacing throughout a predetermined third angle of rotation range of the main shaft of the loom. 2. A method according to claim 1, characterised In that the intermingling process commences before the inserted weft yarn is severed from the weft thread held in readiness. 3. A method according to claim 1, characterised in that the first predetermined angle of rotation range within a weaving cycle lies between about 50° and 30°. 4. A method according to claim 1, characterised in that the second predetermined angle of rotation range within a weaving cycle lies between about 220° and 280°. 5. A method according to claim 1, characterised in that the third predetermined angle of rotation range within a weaving cycle lies between about 320° and 350°, 6. A method according to claim 1, characterised in that the intermingling process is performed in the mixing tube of the main nozzle. 7. A jet loom, especially an air jet loom, having pattern-controlled insertion of the weft yam for implementing the method according to any one of claims 1 to 6, comprising at least one main nozzle (1), with injector (2) and mixing tube (3), in the weft insertion direction (15) downstream of the injector (2) a gripping device (6) arranged in the mixing tube (3) for gripping the weft yarn (7), in the weft insertion direction (15) downstream of the gripping device (6) an intermingling device (16) arranged in the mixing tube (3) or at the output side of the mixing tube (3), and means for forming a shed and for bringing about a closure of the shed. 8. A jet loom according to claim 7, characterised in that in which the gripping device (6) is a central closing means in the form of a pneumatic or hydraulic muscle (8). 9. A jet loom according to claim 7, characterised in that in which the gripping device (6) comprises a pneumatic or hydraulic muscle and two lamellar elements of elastic material integrated in the muscle as gripping means, which together with the muscle form the gripping device. 1Q. A jet loom according to claim 7, characterised in that in which the gripping device (6) comprises two lamellar elements, preferably of elastic material, the position of at least one of the two lamellar elements being adjustable with respect to the other lamellar element by controllable means. 11. A jet loom according to claim 10, characterised in that at least one of the lamellar elements is in the form of a piezo element, 12. A jet loom according to claim 10, characterised in that an electromagnetic means suppliable with power is associated with at least one of the lamellar elements. 13. A jet loom according to any one of claims 7 to 10, characterised in that the gripping device (6) is inserted between a first and a second mixing tube portion (4, 5) of the mixing tube (3). 14. A jet loom having a gripping device (6) and an intermingling device (16) according to claim 7, characterised in that in which intermingling device the mixing tube (3) has at least one intermingling orifice (18) extending transversely to the insertion direction (15) of the weft thread (7) and opening into the inner space of the mixing tube (3), which intermingling orifice is connected by way of at least one controllable magnetic valve (19) to a pneumatic pressure source (22),

Documents:

1115-chenp-2005 abstract duplicate.jpg

1115-chenp-2005 abstract duplicate.pdf

1115-chenp-2005 claims duplicate.pdf

1115-chenp-2005 description (complete) duplicate.pdf

1115-chenp-2005 drawing duplicate.pdf

1115-chenp-2005-abstract.pdf

1115-chenp-2005-claims.pdf

1115-chenp-2005-correspondnece-others.pdf

1115-chenp-2005-correspondnece-po.pdf

1115-chenp-2005-description(complete).pdf

1115-chenp-2005-drawings.pdf

1115-chenp-2005-form 1.pdf

1115-chenp-2005-form 3.pdf

1115-chenp-2005-form 5.pdf

1115-chenp-2005-form18.pdf

1115-chenp-2005-pct.pdf