EP0567428B1 - Process for starting a loom and loom for effecting the same - Google Patents

Description

The invention relates to a method for starting a weaving machine after a standstill phase, in particular after an interruption of the weaving process in order to remedy an error in the formation of the fabric, which weaving machine has a warp let-off device, a goods take-off device, a shedding device and a weaving drawer for attaching a weft thread which is respectively inserted into a shed contains the fabric edge of the fabric, in a first start phase the fabric edge being held in an alternative position distant from a stop position of the sley, a weft feed is blocked in the shed and the weaving machine is driven idle and the edge of the fabric is then returned against the stop position of the sley, and wherein in a second starting phase, the weft thread is entered into the shed.

The invention further relates to a weaving machine for carrying out the method.

In accordance with a known method of the type mentioned at the outset, the edge of the goods is held in a forward avoidance position at a distance from the stop position of the sley until a certain stop force is reached (JP Patent Publication 2-169749). The operational The intended full lifting force is generally achieved in the second weaving cycle, so that in the known embodiment the weft insertion can take place after the first weaving cycle carried out in idle mode. In the production of sensitive fabrics, for example light fabrics for women's outer clothing, visible contact points can appear in the fabric when the weaving machine is restarted to continue the interrupted weaving process. It has been shown that the measures known hitherto, in particular in the case of weaving machines with high speed and correspondingly high weft insertion rate, cannot reliably prevent the formation of such contact points.

The invention has for its object to provide a method, particularly improved in this respect, for starting a weaving machine, in particular for restarting after a malfunction has been remedied, by which the formation of contact points in the fabric is reliably avoided even in weaving machines with a high weft insertion rate.

This object is achieved according to the invention by the features specified in the characterizing part of claim 1.

The inventive control of the shedding device and at least one of the warp let-off and fabric take-off devices, which is independent of the weaving program, permits a targeted influencing of the parameters which are decisive for a uniform fabric image, in particular a restoration of the tension of the warp threads existing before the weaving process is interrupted, until the weaving machine returns to its original, the normal weaving operation has reached the corresponding speed and its corresponding dynamic operating state resulting from the interaction of the individual units. Due to a control signal triggered when this operating state is reached Monitoring device of the weaving machine, the shedding device and the aggregates interacting therewith can be switched over at any time, ie after each of the idling weaving cycles, to the operational weaving program to initiate the second starting phase of the method according to the invention.

Embodiments of the invention are specified in the dependent claims.

The weaving machine according to the invention for performing the method is the subject of claim 5.

Fig. 1

Teile einer zur Durchführung des erfindungsgemässen Verfahrens geeigneten Webmaschine in einer stark vereinfachten Seitenansicht;

Fig. 1a

eine Teilansicht der für eine Ausführungsform des erfindungsgemässen Verfahrens eingerichteten Webmaschine;

Fig. 2

ein Webfachdiagramm der Webmaschine während der Startphasen des erfindungsgemässen Verfahrens, und

Fig. 3 und 4

entsprechende Webfachdiagramme der Webmaschine, je nach einer weiteren Ausführungsform.

Further details emerge from the following description of an exemplary embodiment of the invention shown schematically in the drawing, in conjunction with the claims. Show it:

Fig. 1

Parts of a weaving machine suitable for carrying out the method according to the invention in a greatly simplified side view;

Fig. 1a

a partial view of the loom set up for an embodiment of the method according to the invention;

Fig. 2

a shed diagram of the weaving machine during the starting phases of the inventive method, and

3 and 4

Corresponding shed diagrams of the weaving machine, depending on a further embodiment.

1 contains a warp beam 1, a tensioning beam 2, a shedding device 3 and a sley 4, and a breast beam 5, a goods take-off roller 6, a pressure roller 7 and a goods tree 8. The warp beam 1 is coupled to a warp let-off device 10 according to the arrows 11 and 11a. In a corresponding manner, the goods take-off roller 6 is coupled to a goods take-off device 12 according to the arrows 13 and 13a. Warp threads 14 are guided from the warp beam 1 through the shedding device 3 against a fabric edge 15 and from there as part of a fabric 16 formed there against the fabric tree 8, onto which the fabric 16 is wound. The shedding device 3 contains a number of heald frames 17, only two of which are shown in the drawing, and a drive device 18, by means of which the heald frames 17 can each be adjusted to form a shed 20.

In the shed 20 is in each case via a weft insertion device, not shown, coupled to the main drive of the loom by a weft insertion means, e.g. Compressed air or, as indicated in the drawing, e.g. band-shaped gripper element 21, a weft thread 22 is inserted, which in a stop position 4 'of the sley 4, which can be pivoted via a drive device 23, is attached to the fabric edge 15 and is integrated by a subsequent change of subject.

The drives of the warp let-off device 10 and the take-off device 12 as well as the drive device 18 of the shedding device 3 can each be controlled by a common control device 24 in accordance with a weaving program. The drive device 23 of the sley 4 can be coupled to the main drive of the weaving machine or, as shown, can also be controlled by itself via the control device 24. The control device 24 is in a known manner via signal lines 27, 28, 30; 31, 32 can be influenced by control signals from numerous monitoring devices, by means of which For example, the tension of the warp threads 14 and the weft threads 22 and the state of the fabric 16 formed are detected. In the drawing, a sensor 25 for monitoring the position of the fabric edge 15 and a device 26 for detecting an error, for example an incorrectly inserted weft thread 22, are indicated in the fabric 16 formed. The sensor 25 and the device 26 are connected to the control device 24 via the signal lines 27 and 28, respectively. The drives of the individual units of the weaving machine are coordinated with one another via the control device 24 and controlled in accordance with the predetermined weaving program during normal weaving operation.

If a malfunction occurs, e.g. a warp or weft break or an error in fabric formation, the weaving machine is stopped by a corresponding control signal of the monitoring element in question and, if necessary, for example to remove an incorrectly entered weft thread, by resetting the corresponding units - the warp let-off device 10, the goods take-off device 12 and the shedding device 3 - returned to an operating position intended for the continuation of the interrupted weaving according to the program.

To start the loom after the malfunction has been remedied, the goods edge 15 is moved from the position shown in full lines to one of the stop position 4 'of the sley 4 by stepwise driving the warp beam 1 and the goods take-off roller 6 according to the arrows 11 and 13 respectively removed, dash-dotted alternative position 15 'adjusted and held in this during part of a first starting phase. In this first starting phase, the gear unit connected to at least one unit of the weaving machine, for example the weft insertion device, cannot The main drive of the weaving machine shown is started and then at least one of the other units - the shedding device 3, the warp let-off device 10 and the goods take-off device 12 and optionally the weaving sley 4 - are optionally switched on in succession. Accordingly, the weaving machine - with blocked weft feed to the weft insertion means 21 - is driven for a number, for example two to twenty or more, idle weaving cycles until it has reached its original speed corresponding to normal weaving operation and the original tension of the warp threads 14 is restored and all of their aggregates work together in the appropriate, original rhythm.

During this first starting phase, the shedding device 3 is controlled via the control device 24 independently of the operationally provided weaving program in such a way that the heald frames 17 assume a position in each of the idling weaving cycles that corresponds to an open position of the shed 20 in which the last correctly entered weft thread 22 is securely bound by the warp threads 14 on the fabric edge 15 in the avoidance position 15 '. Depending on the type of fabric to be produced, the heald frames 17, as shown in FIG. 2, can be kept in the same open shed position over all weaving cycles of the first starting phase or, as shown in FIGS. 3 and 4, according to their own, from the operational weaving program different start program can be controlled. If the operating conditions required for the continuation of the operational weaving process are fulfilled, at least one of the monitoring devices of the weaving machine, for example the device 26 assigned to the fabric 16 or a guard element (not shown) which detects the tension of the warp threads 14, is triggered via the control device 24 in response to a corresponding control signal a reverse rotation of the warp beam 1 and / or the take-off roller 6 in the direction of the arrows 11a and 13a is initiated and the edge of the goods 15 is returned against the stop position 4 'of the sley 4.

In the second starting phase, the shedding device 3, the warp let-off device 10 and the take-off device 12 are again activated according to the operationally predetermined weaving program in the sense of a continuation of the interrupted weaving process, the weft thread 22 being transferred to the weft insertion means 21 into the shed 20 formed according to the weaving program , is struck on the edge of the goods 15 and is integrated by a program change following the program. Since this weft insertion occurs due to the starting method according to the invention with the same warp thread tension and under the same dynamic operating conditions as the weft insertion carried out before the interruption of the weaving process, the formation of a visible contact point in the fabric can be avoided in most cases.

In certain cases, e.g. in the production of extremely thin, almost transparent fabrics, it has been shown that, depending on the thread material to be processed, fabric strips may appear on the weft entries following the first weft insertion after the second start phase II, although all of the above-mentioned Aggregates of the weaving machine have reached the operating condition required for normal weaving operation and the tension of the warp threads as well as the speed of the weaving machine and all other parameters match the corresponding values before the weaving process is interrupted. In order to also prevent such, relatively rarely occurring, deviations in the tissue image, according to one embodiment of the method according to the invention, the method shown in FIG Dodge position 15 'moved back edge of goods 15 at the end of the first start phase I into a compensation position 15a or 15b indicated in FIG. 1a and held in this position, which is an adjustable amount relative to a desired position corresponding to the stop position 4' of the sley 4 Undersized in position 15a or a corresponding excess in position 15b - is offset.

This degree of displacement corresponds to a defined fraction, e.g. 20 to 60% of the warp and fabric feed determined by the weaving program after each weft insertion and is in each case, e.g. can be influenced in accordance with the properties of the warp and / or weft material to be processed, via the warp let-off device 10 and / or the goods take-off device 12 or by appropriate activation of the tensioning tree 2 and / or the breast tree 5. After the first weft insertion carried out in the second starting phase II, the goods edge 15 is removed from the compensating position 15a or 15b in a predetermined number, e.g. one to ten or more, the same sub-steps each before one of the following weft entries into a corresponding intermediate position and finally into the target position.

In this way, the operationally constant weft density of the fabric 16, determined by the set warp and fabric feed, can vary within the predetermined limits and thus prevent the occurrence of a fabric defect that occurs in particular within a selectable fabric section limited by the number of partial steps , if, at constant weft density, the wrap angle of the warp threads wrapping around the weft threads deviate from a target value which is established in normal weaving operation. By This embodiment of the method according to the invention can thus compensate for different wrap angles of the warp threads wrapping around the weft threads and can be gradually adjusted to the operational target value of this wrap angle. Accordingly, the formation of a visible contact point in the tissue 16 can be prevented and an essentially uniform tissue image can be achieved.

The direction and the degree of the required displacement of the compensation position 15a or 15b relative to the stop position 4 'of the sley 4 can e.g. when weaving the weaving machine covered with the corresponding warp and weft material, determined by starting operations of the weaving machine carried out on a trial basis and adjusted in accordance with the result that can be achieved in the process. By appropriate programming of the control device 24, e.g. The described correction of the position of the goods at the edge of the goods can be carried out automatically in each case by actuating the tensioning tree 2 and / or the breast tree 5.

To control the shedding device 3 during the first starting phase, a separate control unit 24a can be provided in the control device 24, which can be activated during the first starting phase and can be switched off before the start of the second starting phase. A corresponding control unit 24a can also be designed as an installation part, which can optionally be installed in an existing control device, for example for retrofitting an existing weaving machine. Instead of the described shedding device 3 with heald frames 17, another shedding device, e.g. a jacquard device may be provided.

2 shows a shed 20a with one before the interruption of the weaving process in a weaving cycle Wa entered weft 22a, a shed 20b formed in accordance with the predetermined weaving program for the next weft insertion with a weft 22b entered in a weaving cycle Wb and a subsequent shed 20c with a weft 22c entered in a weaving cycle Wc. The shed 20b is held in the open position over a plurality of, as shown, five weaving cycles W1 to W5 of the first start phase I as well as in the weave cycle Wb of the second start phase II, in which the weft thread 22b is entered according to the program.

As can be seen from FIG. 3, the first start phase I can extend over a number, as shown four idle weaving cycles W1 to W4, the weaving shed 20b described above being formed in the weaving cycles W1, W3 and Wb, while in the weaving cycles W2 and W4 each form a different shed 20x, which does not appear in the operational weaving program, so that the weft thread 22a is securely bound.

According to the representation according to FIG. 4, the shed 20b can be held in the corresponding open position over several, as shown three, idle weaving cycles W1, W2 and W3 and combined with the shed 20x formed in the idle weaving cycle W4.

Claims (6)

1. A method of starting a loom after a phase at standstill, especially after an interruption of the weaving process for the purpose of removal of a fault in the formation of the fabric, the said loom comprising a warp let-off motion (10), a cloth take-up motion (12), a shed-forming motion (3) and a sley (4) for beating up a weft yarn (22; 22a, 22b, 22c) inserted into a shed (20; 20a, 20b, 20c) respectively, where in a first phase (I) of the start the fell (15) of the cloth is held in an alternative position (15') removed from a position (4') of the sley (4) in beat-up, a feed of weft yarn into the shed (20; 20b) is blocked and the loom is driven running idly, and also the fell (15) of the cloth is subsequently carried back towards the position (4') of the sley (4) in beat-up, and where in a second phase (II) of the start the weft yarn (22; 22b) is inserted into the shed (20; 20b)
   characterized in that in the first phase (I) of the start, via a control equipment (24) which is provided for operative control of the loom to correspond with a predetermined weaving programme, the shed-forming motion (3) as well as the warp let-off motion (10) and/or the cloth take-up motion (12) during a number of weaving cycles (W1, W2, W3, W4, W5) are driven independently of this weaving programme,

   that the shed-forming motion (3) is held in each of the weaving cycles (W1 - W5) executed running idly in a operative position corresponding with an open position of the shed (20; 20b, 20x) in which the weft yarn (22; 22a) lying at the fell (15) of the cloth is held bound in,

   that the fell (15) of the cloth during said weaving cycles (W1 - W5), controlled via the warp let-off motion (10) and/or the cloth take-up motion (12), is advanced to the position (4') of the sley (4) in beat-up, and

   that in the second phase (II) of the start, after reaching the original values of the r.p.m. corresponding with the normal weaving operation and of the corresponding dynamic operative state of the cooperating units of the loom, the shed-forming motion (3) as well as the warp let-off motion (10) and the cloth take-up motion (12) are driven in the sense of a continuation of the weaving process according to the weaving programme.
2. A method as in Claim 1, characterized in that during at least part of the first phase (I) of the start the shed-forming motion (3) is held in an operative position corresponding with an open position of the shed (20; 20b) extending over a number of weaving cycles (W1, W2, W3; W4, W5).
3. A method as in Claim 1 or 2, characterized in that
      during at least part of the first phase (I) of the start the shed-forming motion (3) is driven according to a starting programme of its own which deviates from the weaving programme and in at least one of the weaving cycles (W2, W4) is held in an operative position which corresponds with an open position of a shed (20x) not contained in the weaving programme.
4. A method as in one of the Claims 1 to 3, characterized
      in that at the end of the first phase (I) of the start the fell (15) of the cloth is carried into a compensating position (15a resp. 15b) which is associated with the position (4') of beat-up of the sley (4) and with respect to a desired position corresponding with the position (4') of beat-up is offset by a dimension which corresponds with a definite fraction which may be influenced, e.g., via the control equipment (24), of a feed of the fabric (16) determined by the weaving programme and provided after each weft insertion, and after the first weft insertion effected in the second phase (II) of the start is carried from this compensating position (15a resp. 15b) towards the desired position in a predetermined number of partial steps, in each case before one of the following weft insertions.
5. A method as in one of the Claims 1 to 4, characterized
      in that first of all a main drive of the loom is started which is connected through gearing to at least one unit of the loom, e.g., a weft insertion motion, that during the succeeding weaving cycles (W1 - W5) of the first phase (I) of the start at least one further unit - the shed-forming motion (3), sley (4), warp let-off motion (10) and cloth take-up motion (12) - chosen one after another, is switched on at a time and that in the second phase (II) of the start the weft yarn (22) is fed to a weft insertion means (21) and/or released for the weft insertion.
6. A loom for the performance of the method
      as in one of the Claims 1 to 5, characterized in that the control equipment (24) exhibits a control unit (24a) which may be activated during at least the first phase (I) of the start and may during the second phase (II) of the start be switched off in dependence upon a control signal from a monitoring device on the loom, e.g., a detector element (25) for picking up a predetermined position of the fell (15) of the cloth, and allows a drive of the shed-forming motion (3) as well as the warp let-off motion (10) and/or the cloth draw-off motion (12), which is independent of the weaving programme operatively foreseen.

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