EP2098625A1 - Method and loom with a device for preventing weaving in - Google Patents

Abstract

The method involves carrying no separation of a last filling thread (11) after detecting a knot. The filling thread is inserted and hooked before the disconnection of the web process. A shed formed for the filling thread is kept open and an adjacent pneumatic transported section of the filling thread is removed by the shed to the last registered filling thread of the goods-edge. An independent claim is included for a weaving machine with main blast nozzle.

Description

The invention relates to a method for avoiding interweaving of weft threads with knots or the like during a weaving operation according to the preamble of claim 1 and a loom with a device for avoiding weave of knots or the like according to the preamble of claim 7.

It is known ( EP 0 562 230 A1 ), the weft yarns, which are kept ready during a weaving from a supply and pneumatically registered in formed of warp threads sheds to check for the presence of a knot or the like. Upon detection of such an irregularity, the weaving process is interrupted after the last inserted weft yarn has been struck at the edge of the fabric and separated from the supply. It Then, by means of several shots, the section of the weft thread containing the irregularity is transported through the shed formed after the last inserted weft thread and is not woven into the fabric. Subsequently, the transported through the shed section is separated from the supply, after which the weaving process is resumed. This known method works successfully in most cases, so that weft threads with knots are prevented from being woven into the fabric. In some cases, however, problems may arise, especially when weft threads are woven with a particularly smooth outside. It may then be the case that the last inserted weft thread is not firmly enough involved so that it loosens when the shed is open for transporting the portion with the knot or the like. The last inserted weft thread can then loosen and contract, so that in the subsequent resumption of the weaving process in the tissue a flaw arises that can not be uniformly colored, for example. This problem also occurs when a relatively large "pre-cloth" is present, ie a relatively large distance between a stop line and a fabric support is present. Also in this case, possibly a single striking is not sufficient to secure the last registered weft sufficiently.

The invention has for its object to provide a method of the type mentioned above, which certainly prevents the weaving of weft threads with knots or the like, but avoids a defect in the fabric even with difficult weft threads.

This object is achieved in a method according to the preamble of claim 1, characterized in that no separation of the last before Interrupting the weaving process registered and posted weft yarn is performed or made, the shed previously formed for this weft shed is kept open and that then pneumatically transported through the shed through section of the weft yarn removed the last weft inserted from the edge of the fabric and transported through the shed.

In this way, the last entered before the interruption of the weaving process and posted weft thread is taken and removed from the tissue. Only the previously inserted weft yarn remains in the fabric that has been hit twice, i. after this weft was entered and after the last recorded weft was struck. Due to the two-time striking this weft yarn improved integration has been achieved, so that the risk is significantly reduced that this weft loosens and contracts, for example, when opening a subsequent shed. The risk of a defect in the tissue is significantly reduced in this way.

It is known to transport several shots through a shed in order to remove a previously inserted weft thread from the edge of the fabric, after the weaving process has been interrupted and the shed present for the insertion of the last weft thread has been restored ( EP 310,804 B1 ). This procedure is used to automatically remove a faulty (too short) weft thread from the fabric. In this method, the arrival of the weft thread on the side opposite the entry side is checked. If no arrival of a weft thread is detected, then the weaving process is interrupted, the separation of the last inserted (faulty) weft thread from the supply prevents weft yarns, brought back the shed in the occupied during the entry of the last weft position and then the weft thread by means of several shots through the shed passes therethrough. The weft inserted during this process pulls or removes the incorrectly inserted weft thread from the edge of the fabric. Subsequently, the entered in the troubleshooting section of the weft thread is separated from the stock and transported away with the incorrectly entered weft thread, after which the weaving process is resumed.

In a weaving machine according to the preamble of claim 7, the object is achieved in that a program affects a weft scissors, so that the last registered weft is not separated from the stored stock, and by means of the shedding device, the shed is kept open, the last registered Weft, and the Hauptblasdüsen and the relay nozzles are actuated to transport the portion with the node or the like through the shed.

• Fig. 1 zeigt eine perspektivische Teilansicht einer Webmaschine, genauer einer Luftdüsenwebmaschine und
• Fig. 2 bis 7 Draufsichten auf eine schematische Darstellung dieser Webmaschine während der einzelnen Phasen der Durchführung des erfindungsgemäßen Verfahrens.

Further features and advantages of the invention will become apparent from the subclaims and the embodiment illustrated below in the description.

• Fig. 1 shows a partial perspective view of a weaving machine, more specifically an air jet loom and
• Fig. 2 to 7 Top views of a schematic representation of this loom during the individual phases of carrying out the method according to the invention.

On the illustrated air-jet weaving machine, a fabric 12 is formed from warp threads 10 and weft threads 11. The warp threads 10 are raised and lowered by means not shown shedding means, so that the warp threads form a shed into which individual weft threads 11 are registered. The weft threads 11 are withdrawn from a supply, for example a supply reel 13 and stored by means of a Wickelarms 14 on a drum of a Vorspulgeräts 15 in several turns 16. The wrapping arm 14 and the feeder 15 are part of a storage unit. The turns 16 are released, for example, by means of a magnetically actuated stopper 17, when in each case a certain length of weft thread is entered into a shed. The stopper 17 is for example a magnetic pin or pin. The windings 16 are part of the released stock.

The individual weft threads are introduced pneumatically by means of two main jet nozzles 18, 19 arranged one behind the other and relay nozzles 20 which can be arranged within the shed. The main blowing nozzle 19 and the relay nozzles 20 are arranged on a sley 21 which is driven in a reciprocating motion. In addition to the main blowing nozzle 19 and the relay nozzles 20, the sley 21 also carries a reed 22 which has a multiplicity of lamellae which form a weft insertion channel 23.

On the side opposite the entry side of the shed a stretching nozzle 24 is arranged, which sucks an incoming weft thread and keeps stretched. The arrival of a weft thread on the side opposite the entry side is checked by means of a weft detector 25.

The yarn end of the feed reel 13 in use is connected to the beginning of another supply reel 26, so that when the supply reel 13 is in use, the weft yarn 11 is withdrawn from the next supply reel 26 without this giving rise to an interruption gives. The thread end of the supply reel 13 in use is usually connected to the beginning of the weft thread of the further supply reel 26 by means of a knot 31. The connection point, usually a node, is held in a bobbin change detector 27.

When the first supply spool 13 is used up, the junction of the weft threads of the first supply spool 13 and the second supply spool 26 is pulled out of the bobbin change detector 27. The signal of the bobbin change detector 27 is evaluated to indicate that a knot or the like, for example, another defect, is present in the weft yarn 11. This signal then triggers a program, in particular a control system by which is automatically prevented without intervention of an operator that this node or other defect of the weft thread 11 is woven into the fabric 12. In a modified embodiment, instead of a bobbin change detector 27, a thread monitor is disposed between the supply bobbins 13 or 26 and the wrapping arm 14 which monitors the weft yarn for knots or similar defects and then calls the program and / or the control system accordingly. The program or control system is part of a control and regulating device of the loom.

On the entry side next to the shed nor a thread clamp 28 and a weft cutter 29 are arranged stationary, ie they do not move together with the sley 21. The thread clamp 28 and the weft scissors 29 are in the area a stop line 30 at which the registered weft threads are struck by means of the reed 22 to the edge of the goods. During the weaving operation, the weft scissors 29 is actuated immediately after striking a weft thread, so that the main blowing nozzle 19 can then move back into the insertion position with the weft end coming from the supply. The weft cutter 29 is actuated when the weft guard 25 has detected a registered weft.

By means of the signal indicating a knot or the like in the weft 11, in particular by means of the signal of the bobbin change detector 27, a program is started, which prevents the knot of the weft thread is woven into the fabric 12. Since a larger number of turns 16 are wound on weft 11 usually on the drum of the feeder 15, which is sufficient for several shots, the program can be started after a predetermined number of shots has been performed. Since often the thread end of a supply reel 13 or 26 has a reduced quality due to deformations or the like, however, it can be provided that the program is started immediately with the aforementioned signal, so that also the portion of the weft thread which lies before the actual knot, is not woven into the fabric 12.

If a node is detected, for example by means of the bobbin change detector 27, and the weft thread 11 is withdrawn from the next supply spool 26, then the program described below is triggered immediately or after a predetermined number of shots. A shot is first of all carried out, ie a length of weft thread entered into the shed and struck against the stop line 30 of the fabric edge of the fabric 12. However, the weft scissors 29 is not operated, so that the registered and posted weft thread is not separated, but remains connected to the supply. For this purpose, it can be provided that the signal for actuating or moving the weft cutter 29 is suppressed, or that by means of a mechanical clamping the operation or the movement of the weft cutter 29 is prevented. This can also be done in a way that, for example, out EP 284.766 A1 is known. The thread clamp 28, if a thread clamp is even present, is not actuated ( Fig. 2 ), so that the struck weft thread is not clamped. This can also be done in a way such as off EP 284.766 A1 known. The weaving process is interrupted and the sley 21 with the reed 22, the Hauptblasdüse 19 and the relay nozzles 20 is moved back to a position remote from the stop line 30 position ( Fig. 3 ), in which the relay nozzles 20 protrude into the shed. For this purpose, the reed 22 does not need to be in the furthest from the stop line 30 position. This can also be done in one EP 310,804 A1 be carried out known manner. The non-separated weft thread thus extends from the edge of the fabric at the stop line 30 to the exit from the main blowing nozzle 19. To avoid thereby overloading the weft yarn, a turn 16 is optionally released at the Vorspulgerät 15 by releasing the stopper 17. The shedding devices, such as propulsion devices with heddles or Jacquardeinrichtungen or the like, are brought into the position in which they were when entering the last weft thread, so that the shed for the last registered weft thread is kept open. In this context, this may mean that the shed is open, remains open or reopens. The shed should be kept sufficiently open to allow the inventive method. However, it is not necessary for the shed to be kept fully open or as much as during the weaving process. If the signal, which is triggered by a knot or the like in a weft, is evaluated or used so that several shots are then entered, the weaving process can be interrupted so that the last registered weft is posted but not the shed is changed. The last weft inserted was not included. In this case, the warp threads need not be moved back through the shedding means to reopen the shed and keep it open. An interruption without closing the shed for the last weft inserted, is especially possible if the shedding device, such as a dobby or a Jacquardeinrichtung, a separate drive or programmable for this purpose control device is provided.

Subsequently, the program causes a plurality of shots to be transported or entered by the main blowing nozzles 18, 19 and the relay nozzles, correspondingly releasing thread length 17 on the feeder 15 by opening the stopper 17 (FIG. Fig. 4 ). The case newly entered weft is connected to the last registered weft thread, which abuts against the stop line 30. This newly registered weft yarn therefore takes during its transport through the shed through the last registered weft thread with and also transports this to the entry side opposite side ( Fig. 4 ). This thread section is picked up by the stretching nozzle 24 to be removed as waste ( Fig. 5 ).

After a sufficient number of shots, by means of which the thread section has been transported with the knot safely through the shed, this section is separated from the supply. For this purpose, the sley is moved with the reed 22 in the vicinity of the stop position, ie in the position in which the weft thread of the weft cutter 29 has been delivered ( Fig. 6 ). The weft thread is then cut off and removed by means of the stretching nozzle 24 as waste. Subsequently, or during removal, the sley 21 is again brought into a position remote from the stop line 30, so that the normal weaving process can be resumed ( Fig. 7 ).

When using a main drive motor that allows slow speed, for example, only ten percent of the speed during the weaving operation, removal of the section with the knot or the like may be performed without stopping the sley drive. Although the weaving process is interrupted, but without the weaving machine being stopped.

In the method according to the invention, the weft thread which was last entered and struck before interrupting the weaving operation is removed, since this weft thread could possibly not be securely fastened in order to maintain its position during the time in which the subsequent shed is opened. This risk is significantly lower in the weft thread incorporated as the penultimate weft because it has been struck twice, i. once for yourself and then again with the last recorded weft.

In order to prevent weft threads with a knot or the like from being woven into a fabric, in one embodiment the prepared weft thread checked for the presence of a knot or the like, wherein upon detection of a knot or the like, the weaving process is interrupted, the separation of the last entered and damaged weft thread is prevented or avoided, the previously formed for this weft shed is opened and then pneumatically a section weft yarn with the knot or the like is transported through the shed, which entrains the last registered weft thread and also transported away from the shed.

In the illustrated embodiments, a weft insertion set is shown with Hauptblasdüsen 18, 19 and corresponding supply. Nevertheless, it may be provided in other embodiments that weft threads of several weft insertion sets are woven, for example in so-called multi-color weaving, in which case preferably several corresponding sets of main blowing nozzles 18, 19 are provided with corresponding stocks. Here, the inventive method for each weft insertion set can be carried out for themselves.

A method and a weaving machine according to the invention represented by the claims are not limited to the illustrated and described embodiments but may also include modifications and combinations thereof which fall within the claims.

Claims (11)

A method of avoiding interweaving weft yarns (11) with a knot or the like during a weaving operation in which the weft yarns are held by a supply and pneumatically deposited in sheds formed of warp yarns (10), struck at the fabric edge, and separated from the supply, wherein the stocked weft ready from the supply is checked for the presence of a knot or the like, and when a knot or the like is detected, weaving is stopped and a portion of weft yarn containing the knot is pneumatically transported through an open shed from the supply, followed by the weaving process is continued with the striking and severing of the weft threads, characterized in that after the detection of a knot or the like no separation of the last weft thread entered and broken before the interruption of the weaving process is carried out, which for this weft Aden formed shed is kept open and that the then pneumatically transported through the shed through section of the weft yarn removed the last inserted weft thread from the edge of the fabric and transported through the shed. A method according to claim 1, characterized in that the newly removed during removal of the last inserted weft thread from the edge of goods weft from the prepared stock (13, 26) is separated and transported through the shed before it is continued the weaving process. A method according to claim 1 or 2, characterized in that the checking of the weft thread (11) on nodes or the like is carried out before the weft thread with a memory (14, 15) is stored, from which the weft thread is withdrawn for a weft insertion. Method according to one of claims 1 to 3, characterized in that the memory (14, 15, 17) weft thread releases when the sley (21) is brought into a position remote from the edge of the fabric. Method according to one of claims 1 to 4, characterized in that after detecting a node or the like, a predetermined number of weft insertion is carried out before the weaving process is interrupted. Method according to one of claims 1 to 5, characterized in that a movement of the thread connection between an in-use supply spool (13) on weft and a further supply spool (26) is evaluated as information about the presence of a knot or the like in the weft. Weaving machine with at least one main blowing nozzle (18, 19) and relay nozzles (20) for pneumatically feeding weft yarn (11) held by a supply into sheds formed by warp yarn (10) with a reed (22) for striking the inserted weft yarns on a cloth edge and with an on the entry side arranged weft scissors (29) for separating the inserted weft thread between the Hauptblasdüse (19) and the fabric edge, and with means (27) for checking the held weft thread (11) on knots or the like, the connected to a control and regulating device of the weaving machine, which is a program which is activatable on the basis of a signal indicating means (27) for checking knotting or the like and whose operation is interrupting the weaving operation, keeping the shed open by means of the shedding means and pneumatically transporting a portion of the weft yarn containing the knot or the like through the shed Web shed caused, characterized in that the program prevents separation by the weft scissors (29), so that the last inserted weft is not separated from the stored stock, which is kept open by means of the shedding device, the shed, which received the last registered weft and causing the main blowing nozzle (18, 19) and the relay nozzles (20) to move to transport the node-like portion or the like through this shed. Weaving machine according to claim 7, characterized in that the program after removal of the node or the like containing portion and the last weft inserted thread causes a separation of the portion of the held weft yarn. Weaving machine according to claim 7 or 8, characterized in that a Vorspulgerät (14, 15, 17) is arranged in front of the Hauptblasdüsen (18, 19), and that the means for checking the weft yarn on nodes or the like upstream of this Vorspulgerät is arranged. Weaving machine according to one of claims 7 to 9, characterized in that the program during the holding open of the shed for the last registered weft yarn to a signal the prewinder (14, 15, 17) emits, which causes a defined length of weft yarn is released. Weaving machine according to one of claims 7 to 10, characterized in that a bobbin change detector (27) is provided, whose signal is evaluated as detecting a node or the like.

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