Method for operating an air jet loom and air jet loom

Abstract

In a method for operating an air-jet loom, a shuttle opening (4) is formed by alternating raising and lowering of warp threads (3) according to the weave pattern using a shuttle opening forming means. The weft threads (6) are inserted by air nozzles distributed across the weaving width and beaten by the reed. The air-jet loom has a first drive unit for driving the reed, which defines the loom angle (WMW), and at least one second drive unit for driving the shuttle opening forming means. The weft threads (6) are beaten at a loom angle (WMW) of 0°. The shuttle opening closing angle (FSW), at which the shuttle opening (4) is closed, is adjusted by a control unit with respect to the loom angle (WMW). The shuttle opening closing angle (FSW) is adjusted to the loom angle (WMW) located after the weft threads (6) are beaten for normal weaving operation.

Description

Technical Field

[0001] The present invention relates to a method for operating an air jet loom, in which a shed is formed by alternately raising and lowering warp threads according to a weave pattern by shed forming means, a weft thread is inserted by air nozzles distributed over the weaving width, and beating-up is performed by a reed. In this case, the air jet loom has a first drive for driving the reed, which defines the loom angle, and at least one second drive for driving the shed forming means. The beating-up of the weft thread is performed at a loom angle of 0°, and the shed closing angle at which the shed is closed is adjusted by a control unit with respect to the loom angle. The corresponding air jet loom further has a control unit for controlling the drive and for adjusting the shed closing angle with respect to the loom angle.

[0002] Loom is basically known in the prior art. The loom has a shed forming device provided with shed forming means for alternately raising and lowering warp threads, whereby the shed is alternately opened and closed. The loom further has weft insertion means for inserting a weft thread into the opened shed. After the weft thread is inserted, the inserted weft thread is beaten up by a reed, and then the shed is opened again for the next weft thread insertion. Furthermore, a predetermined weave pattern can be produced by raising and lowering the warp threads as intended by the shed forming means.

[0003] German Patent No. 102011006368 describes a loom equipped with a first motor for driving the loom and a second motor for driving a shuttle-forming means. In this case, the synchronization of the two motors is controlled by a signal from a control unit. The first motor, in this case, defines the loom angle. In this case, the weft is always beaten at a loom angle of 0°. In such a type of loom equipped with a separate drive for driving the shuttle-forming device, the shuttle-closing angle at which the shuttle is closed can be adjusted to various points in time with respect to the loom angle. When the shuttle is closed and subsequently opened, individual warp threads of adjacent warp groups may become entangled with each other. A shuttle is not formed between these warp threads. Therefore, during subsequent weft insertion, these entangled warp threads can cause problems such as weft breakage and warp breakage. To avoid this, this paper proposes changing the fusel opening closure angle so that a sequence of increasing and decreasing fusel opening closure angles is formed during weaving. However, as is typical in the prior art, all fusel opening closure angles are positioned well before the reed. This reduces the tendency for the warp threads to tangle.

[0004] In an air-jet loom, a row of air nozzles distributed across the weaving width is provided as a weft insertion means, and these air nozzles transport the weft through the shuttle. In this case, the nozzle's spray position can affect the transport of the weft through the shuttle. Therefore, the working position of the air nozzles can be adjusted. In an air-jet loom known from European Patent No. 2535446, the spray position of the air nozzles is defined in relation to various weaving conditions in a database and then adjusted accordingly to these weaving conditions. This is done by an actuator, which allows for adaptation to weaving conditions that change during the process.

[0005] However, with air jet looms, there is a risk of damage to the warp threads due to the air nozzles. In particular, when the warp density is relatively high, there is a risk of capillary damage to the warp threads due to the air nozzles.

[0006] The object of the present invention is to propose a method for operating an air jet loom and an air jet loom that at least reduces damage to the warp threads.

[0007] This problem is solved by a method for operating an air jet loom having the features of an independent claim, and by an air jet loom.

[0008] In a method for operating an air-jet loom, a shuttle opening is formed by alternating raising and lowering of the warp threads according to the weave pattern using a shuttle opening forming means. The weft threads are inserted by air nozzles distributed across the weaving width and beaten by the reed. In this case, the air-jet loom has a first drive unit for driving the reed, which defines the loom angle, and at least one second drive unit for driving the shuttle opening forming means. The weft beating is performed at a loom angle of 0°, and the shuttle opening closing angle, at which the shuttle opening is closed, is adjusted by a control unit with respect to the loom angle.

[0009] It is proposed to adjust the shuttle closure angle to the loom angle located after the weft is beaten, for normal weaving operation. In other words, the shuttle closure angle is adjusted so that, at least for normal operation, the shuttle is still open when the reed is beaten and only closes afterward. The applicant has found that when the shuttle closure angle is located after the reed is beaten, the insertion angle of the air nozzles relative to the warp threads acts on the warp threads much more gently. This helps to avoid capillary damage to the warp threads. This is particularly advantageous in untwisted filament yarns, which are particularly susceptible to such damage. In particular, in densely woven warp threads, this can significantly improve the quality of the woven fabric.

[0010] Similar advantages can also be achieved by a corresponding air-jet loom and a corresponding computer program, and patent protection can be claimed for these as well. The air-jet loom has a control unit for controlling the drive mechanism and for adjusting the shuttle closure angle with respect to the loom angle. The control unit is formed to carry out this method. The computer program, when implemented by the control unit of the air-jet loom, causes the control unit to carry out the method described above.

[0011] The drive unit may, in this case, be connected directly to the reed or shuttle forming means, or possibly via a transmission means equipped with reduction or variable speed stages. The loom angle corresponds to the angle of the main shaft of the air-jet loom at each step. The main shaft may be a real or virtual shaft operating for a 360° weaving cycle, with each count starting at 0° during a beat and ending at the next beat. However, in this case, the loom angle is determined by the first drive unit, since the first drive unit sets the angular position of the main shaft of the air-jet loom.

[0012] It is particularly advantageous to adjust the shuttle closure angle to a loom angle of up to 20° after the weft has been beaten. In particular, adjusting the loom angle to 10° to 20° has been found to be extremely advantageous in avoiding damage to the warp threads.

[0013] In this case, according to the first embodiment, the shuttle closure angle can be adjusted to a loom angle of 0° or less for each operating state of the loom in general.

[0014] However, according to the second embodiment, it is particularly advantageous if the adjustment of the shuttle closure angle to the loom angle after the weft is beaten is limited to normal weaving operations. In this way, damage to the warp threads can be avoided during normal weaving operations, but under certain conditions, if it is advantageous, the shuttle closure angle can be adjusted before the weft is beaten, as is common in the prior art. In this case, the FSW can still be adjusted to just before 0° at the start of a normal weaving operation, and the adjustment can only be made within the normal weaving operation.

[0015] However, it is particularly advantageous to use the adjustment of the shuttle closure angle to the loom angle after the weft has been beaten for the entire normal weaving operation.

[0016] It is particularly advantageous to adjust the shuttle closure angle to a loom angle positioned before the weft is beaten, for the automated and / or manual auxiliary movements of the first drive unit and / or at least one second drive unit. For example, during weft break removal, the position of the reed at the shuttle closure angle after the weft is beaten may be inconvenient for weft removal. Therefore, it may be advantageous to adjust to an earlier shuttle closure angle for such automated auxiliary movements of the first drive unit and / or at least one second drive unit. Automated auxiliary movements are understood to be, for example, automatic termination in the process of manual stopping, automatic termination in the process of warp breaking, and automatic termination in the process of weft breaking such as weft searching. In each case, one stop followed by shuttle equalization may be selected. Manual auxiliary movements are understood to be, for example, creep rotation (tapping) and manual weft searching.

[0017] Similarly, for example, adjusting to an earlier shuttle closure angle may be advantageous for shuttle equalization and creep rotation operation.

[0018] Furthermore, it is advantageous to adjust the shuttle closure angle during the startup phase of the air-jet loom to a loom angle that is positioned after the weft is beaten. In this case, the shuttle closure angle adjusted in this way can already correspond to the shuttle closure angle during normal weaving operation. Alternatively, the shuttle closure angle during the startup phase can be adjusted to a loom angle different from the shuttle closure angle during normal weaving operation. It is particularly advantageous to gradually shift the shuttle closure angle during the startup phase from an earlier point, sometimes even before the weft is beaten, to a later point, after the weft is beaten.

[0019] Similarly, if the shuttle closure angle is adjusted during the stopping phase of the air-jet loom to the loom angle positioned before the weft is beaten, it also brings advantages. This is advantageous because, in this case, favorable positions for the first and second drive units relative to each other already exist for the automated termination or the introduction of automated or manual auxiliary movements following the loom stop.

[0020] Furthermore, it is advantageous if the shuttle closure angle can be adjusted while the air-jet loom is in operation. This allows different shuttle closure angles to be set for various weaving cycles during weaving, and these angles can be targeted over one or more weaving cycles. In this case, the shuttle closure angle can also be adjusted to a predetermined value for each individual weft thread, i.e., from weaving cycle to weaving cycle.

[0021] It is even more advantageous to shift the shuttle closure angle to the desired value via an intermediate value during the starting and / or stopping phases. This is advantageous in the starting phase because, on the one hand, the first weft is already inserted during the starting phase, and thus a favorable delayed shuttle closure angle is already achieved at the time of the first weft insertion, while on the other hand, the last inserted weft is also joined and positioned in the fabric by this. If the shuttle closure angle is already positioned beyond 0° at the start of the starting phase, the last inserted weft may be exposed again, which could become a starting point defect in the fabric.

[0022] According to the first embodiment of the method, in this case, the Shuttle Closure Angle is shifted stepwise through intermediate values ​​to the value to be adjusted.

[0023] According to another advantageous embodiment, the Shuttle closure angle is continuously shifted to the value to be adjusted. Thus, intermediate values ​​are dynamically passed through without being fixed.

[0024] This still provides a 0° pre-shuttle closure angle immediately before the stop phase or immediately before the start phase that is advantageous for automated termination, which allows the operator to easily retrieve the broken weft, for example, after weft retrieval. This eliminates the need for a separate method for the first and / or second drive mechanism.

[0025] Furthermore, it is advantageous to use a suitable device, such as an edge twisting device or a jacquard machine, equipped with individual drive devices for harness cords, to adjust the shuttle closure angle earlier for the warp threads in the edge region of the fabric to be produced compared to the warp threads in the central region of the fabric to be produced. This allows the inserted weft threads to be joined earlier in the edge region, thereby stretching and fixing the weft threads and preventing them from slipping out.

[0026] It is even more advantageous to adjust the individual shuttle closure angle for each weft insertion according to the weave pattern. This prevents warp entanglement. Furthermore, it allows the shuttle closure angle to be adapted to various weft threads within the fabric.

[0027] In a particular embodiment of the air-jet loom, the shuttle-forming means includes a plurality of heddles. In this case, the method may be carried out in relation to an eccentric machine if it has its own drive device, or in relation to a heddle machine such as a rotary heddle machine, and can be easily implemented by adjusting the degree of synchronization between the drive device of the shuttle-forming means and the drive device of the reed.

[0028] It is even more advantageous if the air jet loom includes an individual drive for each heddle. Thereby, for example, for the edge region, a shed closing angle different from that for the central region can also be adjusted. Of course, similarly, for a predetermined region across the weaving width, a shed closing angle different from that in other regions can also be adjusted.

[0029] According to another embodiment, it is even more advantageous if the shed forming means includes a plurality of harness cords. Therefore, the present invention can also be advantageously used with a Jacquard machine.

[0030] In this case, the air jet loom may have a conventional Jacquard machine.

[0031] However, according to another embodiment, it is also advantageous if the air jet loom includes an individual drive for the harness cords. In this case, a predetermined shed closing angle can also be set for each individual warp thread.

[0032] Further advantages of the present invention will be explained in the following examples.

Brief Description of the Drawings

[0033] [Figure 1] It is a schematic side view showing an air jet loom provided with a first drive for driving a reed and a second drive for driving shed forming means. [Figure 2] It is a schematic front view showing an air jet loom. [Figure 3] It is a diagram schematically showing a method for operating an air jet loom according to the prior art based on a schematic view of a shed. [Figure 4] It is a diagram schematically showing a method for operating an air jet loom according to the present invention based on a schematic view of a shed. [Figure 5] It is a diagram schematically showing the starting stage, operating stage, and stopping stage of an air jet loom according to the prior art in a rotational speed - time graph. [Figure 6a]This figure schematically shows the starting, operating, and stopping phases of an air jet loom according to an embodiment of the present invention in a rotation speed-time graph. [Figure 6b] This figure schematically shows the starting stage of an air jet loom according to another embodiment of the present invention, in a rotation speed-time graph. [Figure 6c] This figure schematically shows the stopping stage of an air jet loom according to another embodiment of the present invention in a rotation speed-time graph. [Figure 7] This is a schematic front view showing another embodiment of the present invention for an air jet loom.

[0034] In the following description of the embodiments, identical features, or features that are at least equivalent in configuration and / or mode of operation, are given the same reference numerals. Furthermore, these embodiments are described in detail only when they are first mentioned, while subsequent embodiments only mention the differences from the embodiments already described. In addition, for the sake of clarity in the drawings, multiple identical components or features are often given reference numerals to only one or some of them.

[0035] Figure 1 shows a schematic side view of the air jet loom 1 as an overview. The air jet loom 1 has a shuttle forming means 2 in a known form, which here is formed in the form of lead wires 18 with lead holes 19 that can alternately raise and lower the warp threads 3 to form shuttles 4. The shuttle forming means 2 may also include heddles and harness cords that operate the lead wires 18, respectively. The warp threads 3 are supplied from the warp beam 8 through the back beam 9 to the shuttle forming means 2 in the warp direction KR. By alternately raising and lowering the warp threads, shuttles 4 are formed sequentially according to the weave pattern. At least one weft thread 6 (see Figure 3) is inserted into each of the thus formed shuttles 4 and beaten by the reed 7. The reed 7 is rotatable between a front end position (shown here by a dashed line) and a rear end position (shown here by a solid line) for repeated beating of the weft yarn 6. The front end position corresponds in this case to beating, that is, the position the reed 7 takes when beating the weft yarn 6. After the weft is inserted, the shuttle opening 4 is closed again, thereby binding the inserted weft yarn 6. The resulting fabric 17 is then drawn out in the warp direction KR by the draw roller 10 and wound onto the crossbeam 11.

[0036] The air jet loom 1 includes a first drive unit 12 for driving the reed 7 of the air jet loom 1 and a second drive unit 13 for driving the shuttle opening forming means 2. In this case, the drive units 12 and 13 may be directly connected to the reed 7 or the shuttle opening forming means 2, or via a reduction gear or speed change gear.

[0037] The reed 7 is connected to the first drive unit 12 via a transmission means that converts the continuous rotational motion of the first drive unit 12 into the reciprocating rotational motion of the reed 7. The first drive unit 12 defines the loom angle WMW (see Figures 3 to 6c), which corresponds to the angle of the main shaft of the air jet loom 1. The main shaft may be a real or virtual shaft that operates in a 360° weaving cycle, with each count starting at 0° during a beat and ending at the next beat. Thus, one complete rotation of the main shaft represents one complete cycle of motion of the reed 7. Therefore, all descriptions of position and rotational speed relate to the main shaft. The first drive unit 12 and the main shaft take the same position or rotate at the same rotational speed only when the gear ratio between the first drive unit 12 and the real or virtual main shaft is 1:1.

[0038] The second drive unit 13 can also be connected to the hull-forming means 2 via a transmission means that may include a reduction gear or a gear shift. The real or virtual axis driving the hull-forming means 2 operates 360° per weaving cycle. This axis defines the angle FMW of the hull-forming means. The count for this begins at 0° at the hull-closed position and ends upon reaching the next hull-closed position. (The hull-closed positions will be discussed further later.)

[0039] In other words, all descriptions of position and rotational speed relate to the shaft that drives the ditch forming means 2, and only when the gear ratio is 1:1 do the second drive unit 13 and the shaft that drives the ditch forming means 2 take the same position or rotate at the same rotational speed.

[0040] To control the drive units 12 and 13, the air jet loom 1 further has a control unit 14.

[0041] Figure 2 shows a schematic front view of the air jet loom 1. For clarity, only the reed 7, which has a weft insertion passage 23 and air nozzles 5 distributed across the weaving width WB, is shown. Furthermore, the first drive unit 12 and control unit 14 for driving the reed 7 are shown.

[0042] As can be seen further in Figure 2, the weft yarn 6 to be inserted is supplied from the weft storage unit 20 to the air jet loom 1 via the pre-winding device 21. The weft yarn 6 is finally inserted into the weft insertion passage 23 of the reed 7 from one or more main nozzles 22 and conveyed through the shuttle 4 (see Figure 1) by air nozzles 5 (also called relay nozzles) inside the weft insertion passage 23.

[0043] Next, Figures 3 and 4 provide a schematic comparison of methods for operating the air jet loom 1 according to the prior art (Figure 3) or according to the present invention (Figure 4). In this case, a schematic diagram of one shuttle 4 is shown for each.

[0044] Figure 3 schematically shows a shed 4 formed by warp threads 3. In this case, the warp threads 3 are located in the upper or lower position (or upper or lower opening) and are alternately moved from the upper position or upper opening to the lower position or lower opening and then returned. In this case, a schematic side view is shown, i.e., a view of the shed 4 in the weft direction or perpendicular to the warp direction KR. Within each such shed 4 formed by warp threads 3, there is, for example, one woven weft thread 6.

[0045] Below the roughly shown shuttle 4, time t is indicated on the horizontal axis. Below the time axis, the loom angle WMW, which indicates the rotation angles of the first drive unit 12 or the main shaft, is also indicated on the horizontal axis. As can be seen from the drawing, the so-called shuttle closure angle is indicated by FSW. In this case, the shuttle closure angle corresponds to the point in time when the path of the warp thread 3 is changed from the upper opening to the lower opening or vice versa during shuttle change (shuttle closure point). In other words, the warp thread 3 occupies the shuttle equalization position at this point. Similarly, the reed beating angle, i.e., the angular position taken by the drive unit 12 or the actual or virtual main shaft at the point when the reed 7 contacts the inserted weft thread 6, is indicated by BAW. At this point, the first drive unit 12 or the main shaft simultaneously occupies the 0° position or the 360° position. As can be seen from Figure 3, in this case, the shuttle closure angle FSW is at a value less than 360° of the loom angle WMW, that is, before the reed 7 makes contact at 0° or 360°, either temporally or angularly. In the prior art, the value for the shuttle closure angle FSW is usually in the range of 300° to 355°.

[0046] In contrast, Figure 4 shows a method for operating the air jet loom 1 according to the present invention. As can be seen from this figure, the shuttle closure angle FSW is greater than 0° or 360° of the loom angle WMW, that is, it occurs after the reed 7 makes contact at 0° or 360°, either temporally or angularly. Therefore, the contact of the reed 7 at the reed beating angle BAW or the loom angle WMW at 0° or 360° occurs while the shuttle 4 is still open. This influences the insertion angle of the air nozzle 5, which rotates with the reed 7 (see Figure 2), into the warp thread 3 that is being replaced by the lower opening, so that the warp thread 3 suffers little to no surface damage or capillary damage from the air nozzle. A shuttle closure angle of 10° to 20° was found to be particularly advantageous.

[0047] Next, Figures 5, 6a, and 6b show a schematic comparison of the starting, operating, and stopping stages of the air jet loom 1 according to the prior art (Figure 5) or according to the present invention (Figures 6a and 6b) in a rotation speed-time graph.

[0048] Figure 5 shows a rotation-time graph of the synchronous starting, operation, and stopping of a first drive unit 12 for the reed and a second drive unit 13 for the shed-to-head forming means, as known from the prior art. In this case, time t is plotted to the right and rotation speed ω is plotted upwards. Furthermore, ω1 represents the rotation speed of the first drive unit 12, and ω2 represents the rotation speed of the second drive unit 13 for the shed-to-head forming means 2. It should be understood that the rotation speeds ω1 and ω2 are shown ideally without fluctuations due to various causes. Both rotation speeds ω1 and ω2 relate to one axis that rotates 360° for each weaving cycle, i.e., from one beating to the next. The angle and position descriptions correspond to this. As already mentioned, in this case the second drive unit 13 can drive a heddle machine or a jacquard machine. Multiple second drive units 13 may be provided as individual or group drive units for the shed forming means 2, which may include heddles or harness cords. Below the time axis, the loom angle WMW, which also corresponds to the angle of the first drive unit 12, and the angle FMW of the shed forming means, which corresponds to the angle of the second drive unit 13 or the angle of the axis driving the shed forming means 2, are further plotted.

[0049] Time t1 here represents the starting of the first and second drive units 12, 13, or the shafts connected to these drive units. As already mentioned with respect to Figures 3 and 4, the reed 7 contact occurs at a loom angle WMW of 0° or 360°. However, as can be seen from Figure 5, the first drive unit 12 of the air jet loom 1 is at an angle of 20° in this example, rather than a loom angle WMW of 0° or 360°, at the time of starting. Such a starting position for the first drive unit 12 or the main shaft is normal in order to reach the operating speed within the first rotation. In contrast, with respect to the second drive unit 13 or the shed forming means 2, the position for shed closing (= shed closing position) is considered to be the 0° position. This corresponds to the position where the warp threads are replaced in a series of shed changes. The angle of the second drive unit 13 is shown as the angle FMW of the shed forming means.

[0050] In the prior art, as already mentioned, the shuttle closure angle FSW is at 0° or 360° of the loom angle WMW before the reed 7 makes contact. In this example, the shuttle closure angle FSW is at 330° of the loom angle WMW. This means that the first drive unit 12 is lagging behind the second drive unit 13 by 30° in this case. Therefore, the second drive unit 13 or the shuttle forming means 2 is not located at the 0° angle FMW of the shuttle forming means at the start, but rather at 50° FMW.

[0051] From time t1 onward, the first drive unit 12 and the second drive unit 13 are now accelerated in sync during the starting phase 15, but they are 30° apart in terms of the incline until they reach the operating speed at time t2. Therefore, if the first drive unit 12 is at WMW0° or 360° at this point, the second drive unit 13 is simultaneously at FMW30°.

[0052] From time t2 onward, the weaving process continues at this operating speed until time t3; the first and second drive units 12 and 13 maintain a 30° staggered synchronization in this case. Then, from time t3 onward, the stopping phase 16 of the air jet loom 1 begins. At this point, the first drive unit 12 again takes the position WMW0° or 360°, and the second drive unit 13 takes the position FMW30°. The stopping of the drive units 12 and 13 is also carried out in the same manner as the starting, with respect to the inclination, until time t4, when both drive units 12 and 13 are finally at rest. At this point, the first drive unit 12 takes the position WMW300°, and the second drive unit 13 takes the position FMW330°. As a result, automated auxiliary movements can be performed depending on the cause of the stop, and these auxiliary movements end at a predetermined position or state, for example, the shuttle equalization position. Then, for the restart of the air jet loom 1, it returns—similarly automated—to the starting position described for time t1.

[0053] In contrast, Figure 6a shows the progression of rotational speeds ω1 and ω2 of the first and second drive units 12 and 13 according to an embodiment of the method according to the present invention. In this case, the shuttle closure angle FSW in the starting stage 15 and stopping stage 16 is shifted to the value to be adjusted in multiple steps (not shown here) or continuously through intermediate values. The time points t1 to t4 correspond to the meaning already explained with respect to Figure 5. Furthermore, ω1 also represents the rotational speed of the first drive unit 12 or the spindle, and ω2 represents the rotational speed of the second drive unit 13 or the shuttle forming means 2. In this case as well, the illustration of rotational speeds ω1 and ω2 is idealized.

[0054] At the start of the startup phase 15 at time t1, the position of the first drive unit 12 is still at WMW20°, and the position of the second drive unit 13 is at FMW50°. However, now, for the normal weaving process from time t2 onward, a 15° spur closing angle should be used with respect to the loom angle WMW. In this case, the first drive unit 12 should again be at WMW0° or 360° at the end of the startup phase 15, i.e., at time t2. However, since the spur 4 of the second drive unit 13 should only be closed after it has come into contact with the reed 7, if the spur closing angle should be 15°, then at this point it must simply be at the 345° position. In other words, this means that the first drive unit 12 is ahead of the second drive unit 13.

[0055] Therefore, the first drive unit 12 operates over an angular range of 340° during the starting phase 15, while the second drive unit 13 operates over an angular range of only 295° during the same time. Consequently, the first drive unit 12 must operate over an angular range 45° larger than that of the second drive unit 13. The starting of the second drive unit 13 is then again performed along the incline. In contrast, the first drive unit 12 is given a special rotational speed profile, shown here in an arc-shaped "convex" manner, to enable it to move over a larger angular range. The area shown by the diagonal lines below the arc corresponds to the speed-time area of ​​the first drive unit 12, which is 45° larger.

[0056] In this case, from time t2 to time t3, the first and second drive units 12 and 13 operate synchronously again, but with a positional shift of 15° set by the shuttle closure angle FSW.

[0057] At time t3, the stopping phase 16 begins again. At this point, the first drive unit 12 takes the position of WMW0° or 360° again. The second drive unit takes the position of FMW345°, corresponding to a 15° shuttle closure angle. At the end of the stopping phase at time t4, i.e., when the first and second drive units 12 and 13 reach a resting state, the position of the first drive unit 12 should be at WMW300° and the second drive unit 13 should be at FMW330°, thereby allowing the subsequent automated process to be introduced by the air jet loom 1. As a result, the first drive unit 12 must operate over an angular range of 300° during the stopping phase 16, while the second drive unit 13 must operate over an angular range of 345°, which is 45° larger than that of the first drive unit 12, during the same amount of time. The stopping of the second drive unit 13 is also performed along the incline. In contrast, the first drive unit 12 is again given a special rotational speed profile so that it can move over a smaller angular range in the same amount of time. This is illustrated by a "concave" arc. The area indicated by the diagonal lines above the arc corresponds to a speed-time area that is 45° smaller than that of the first drive unit 12.

[0058] In addition to the shift of the swivel closing angle FSW during the starting stage 15 and stopping stage 16 as described with reference to Figure 6a, the shift of the swivel closing angle FSW can also be performed by synchronous movement (also called coupled operation) according to alternative embodiments not shown herein. In this case, the relative positions of the drive units 12 and 13 are usually changed by the rotational speed at the creep rotation level, so that usually only the first drive unit 12 or only the second drive unit 13 is moved, while the other drive units 12 and 13 remain stationary. This synchronous movement can be used during the starting stage 15 and stopping stage 16 as an alternative to—or supplement to—the shift of the swivel closing angle FSW described in Figure 6a. To adjust the swivel closing angle FSW for auxiliary movement, the synchronous movement is performed after the stopping stage 16 of the air jet loom 1 and before the start of the auxiliary movement. For the starting stage 15, conversely, the synchronous movement is performed after the stopping of the auxiliary movement and before the starting stage 15.

[0059] Figure 6b refers to a shuttle forming machine that starts and stops gently, as disclosed in German Patent No. 10053079. Here, the coupled operation described above can be used to shift the shuttle closing angle. On the other hand, to change the shuttle closing angle FSW during the stopping phase, the rotational speed profile of the first drive unit 12 can certainly be adapted, as shown in Figure 6a. However, instead, it is also possible and meaningful to influence the starting phase of the second drive unit 13, which is long in any case.

[0060] In Figure 6b, an example is shown in the upper diagram. In this diagram, t1.2 represents the starting point of the second drive unit 13. The starting angle is 50° FMW, as in Figure 6a. This can be read from the angle FMW of the shuttle forming means, which is plotted on the lower central horizontal axis of the loom angle WMW. In contrast, t1.1 represents the starting point of the first drive unit 12. This starting angle is also 20° WMW, as in Figure 6a. Time t2 represents the end of the starting stage for both the second drive unit 13 and the first drive unit 12, and thus the normal weaving process begins.

[0061] As in Figure 6a, the normal weaving process should now utilize a 15° spur closing angle FSW relative to the loom angle WMW. In this case, the first drive unit 12 should again be in the WMW 0° or 360° position at the end of the starting phase, i.e., at time t2. However, the second drive unit 13 should simply be in the 345° position at this point if the spur closing angle FSW should be 15°. However, unlike in Figure 6a, the second drive unit 13 now starts much more slowly; for example, the second drive unit in this case goes through five virtual weaving cycles, each 360°, without the spur forming means 2 switching from the upper spur to the lower spur or from the lower spur to the upper spur. Therefore, the overall angular range in which it operates at startup is (345°-50°+(5×360°)=2095°. In this case, the second drive unit 13 may be started along the incline as shown in the figure. Similar to Figure 5, the first drive unit 12 can also be started along the incline because the single common starting point (see t1 in Figure 6a) has been eliminated and divided into starting points t1.1 and t1.2. ω1 represents the rotational speed of the first drive unit 12, and ω2 represents the rotational speed of the second drive unit 13.

[0062] If, as in the case of the prior art, there was a requirement to maintain a 330° shed closing angle FSW, i.e., even at the start of a normal weaving operation t2, then the second drive unit 13 would have had to start from a starting angle of FMW 50° and, in that starting phase, operate over an angular range of 2140°, which is 45° more than 2095°. This would have required the starting point to be advanced to t1.2x in order to start via the inclination; the dashed line indicates the corresponding rotational speed inclination. The corresponding angle FMWx of the shed forming means is shown on the lowest horizontal axis.

[0063] A stopping phase can be formed in the same way as the starting phase. An example of this is shown in Figure 6c. At time t3, the stopping phase of the first drive unit 12 and the second drive unit 13 begins. At this point, the first drive unit 12 is again at the WMW 0° or 360° position. The second drive unit 13 or the shaft driven by the second drive unit is at the FMW 345° position, corresponding to a 15° shuttle closure angle FSW. At the end of the stopping phase of the first drive unit 12 at time t4.1, i.e., when it reaches a resting state, the position of the first drive unit 12 is at WMW 300°, as in Figure 6a. At the end of the stopping phase of the second drive unit 13 at time t4.2, i.e., when it reaches a resting state, the position of the second drive unit 13 is at FMW 330°, as in Figure 6a.

[0064] However, unlike in Figure 6a, the stopping process of the second drive unit 13 is now performed much more slowly; for example, in this case, the second drive unit goes through five virtual weaving cycles, each 360°, without the burr forming means 2 switching from the upper burr to the lower burr or from the lower burr to the upper burr. Thus, the angular range that operates in the stopping process as a whole is 345° + (5 × 360°) = 2145°. The stopping process of the second drive unit 13 may, in this case, be performed along the incline as shown. The fact that the first drive unit 12 can also be stopped along the incline, as in Figure 5, is due to the elimination of one common point in time for the end of the stopping process (see t4 in Figure 6a) and its division into points t4.1 and t4.2. ω1 again represents the rotational speed of the first drive unit 12, and ω2 represents the rotational speed of the second drive unit 13.

[0065] If there was a requirement to use the 15° shuttle closure angle FSW, which corresponds to the normal weaving process, for auxiliary movement following the resting state, then the second drive unit 13 would only need to operate within an angular range of 2100° instead of 2145° during its stopping phase. This would bring the end of the stopping phase to t4.2x earlier in order to stop via inclination. The dashed line ω2x indicates a corresponding rotational speed inclination. However, this assumes that a shuttle closure angle FSW is permitted, which is adjusted so that the shuttle closure occurs only after beating the reed at FSW 15°, for example, for subsequent auxiliary movement.

[0066] Finally, Figure 7 further shows an air-jet loom 1 in a schematic front view to illustrate another embodiment of the present invention. In this case, a reed 7 is again shown, comprising a weft insertion passage 23 and an arranged air nozzle 5. The warp threads 3 are schematically and symbolically shown above it. Below the reed 7, the shuttle closure angle FSW across the weaving width WB of the air-jet loom 1 is further shown. According to Figure 7, in this case, the shuttle closure angle FSW in the edge region KB of the fabric 17 to be produced (see Figure 1) is smaller than in the central region MB of the fabric 17. This is advantageous because the inserted weft threads 6 (see Figure 2) can be already bound and thus fixed in the edge region KB. This prevents the inserted weft threads 6 from slipping out.

[0067] The present invention is not limited to the illustrated and described embodiments. Variations within the scope of the claims are possible, such as combinations of features, even if illustrated and described in embodiments with different features. For example, the shuttle closure angle FSW can be adjusted according to the pattern. In this case, within the scope of the present invention, an individual shuttle closure angle FSW can be set for each weft insertion. The adjustment of the shuttle closure angle FSW can also be automated in each case by the control unit 14. Therefore, the method according to the present invention can be implemented in existing machines by replacing the control unit 14 or by intervening in the control unit 14. [Explanation of symbols]

[0068] 1. Air jet loom 2 Shall forming means 3 Warp threads 4 Shed 5 Air nozzle 6 weft threads 7 Reed 8 Warp Beam 9 Back beam 10 Drawer rollers 11 Crossbeam 12 First drive unit 13. Second drive unit 14 Control Unit 15. Startup phase 16. Stopping phase 17 Woven fabric 18 Lead wires 19 lead holes 20. Weft yarn storage section 21. Spare winding device 22 Main Nozzle 23 Weft insertion passage KR warp direction WB weaving width WMW Loom Angle FSW Shed closure angle BAW Reed beating angle Angle of the FMW junction forming means FMWx Shuttle opening forming means angle KB Edge area MB central area ω rotation speed ω1 Rotational speed of the first drive unit ω2 Rotational speed of the second drive unit t time t1 Startup t2 Reach of normal weaving operation t3 stop point T4 Reaching the hibernation state t1.1 Starting point of the first drive unit 12 t1.2 Starting point of the second drive unit 13 t1.2x Startup time of the second drive unit 13 t4.1 Reaching the idle state of the first drive unit t4.2 Reaching the idle state of the second drive unit t4.2x Reaching the dormant state of the second drive unit

Claims

1. A method for operating an air jet loom (1), particularly a method carried out by a computer, wherein a shuttle opening (4) is formed by alternately raising and lowering warp threads (3) according to a weave pattern using a shuttle opening forming means (2), weft threads (6) are inserted by air nozzles (5) distributed across the weaving width (WB), and the weft threads are beaten by a reed (7), the air jet loom (1) has a first drive device (12) for driving the reed (7) which defines the loom angle (WMW), and has at least one second drive device (13) for driving the shuttle opening forming means (2), the weft threads (6) are beaten at a loom angle (WMW) of 0°, and the shuttle opening closing angle (FSW) at which the shuttle opening (4) is closed is adjusted by a control unit (14) with respect to the loom angle (WMW), in the method, A method characterized by adjusting the shuttle opening closing angle (FSW) to the loom angle (WMW) located after the weft yarn (6) has been beaten with the reed, for normal weaving operation.

2. The method according to claim 1, characterized in that the shuttle opening closing angle (FSW) is adjusted to a loom angle (WMW) of up to 20° after the weft (6) has been beaten on the reed, and in particular to a loom angle (WMW) of 10° to 20°.

3. The method according to claim 1 or 2, characterized in that the adjustment of the shuttle opening closing angle (FSW) to the loom angle (WMW) of the weft yarn (6) after beating the reed is limited to the normal weaving operation.

4. The method according to claim 3, characterized in that the adjustment of the shuttle closure angle (FSW) to the loom angle (WMW) of the weft yarn (6) after beating the reed is used for the entire normal weaving operation.

5. The method according to any one of claims 1 to 4, characterized in that the shuttle closing angle (FSW) is adjusted to the loom angle (WMW) positioned before the reed beating of the weft (6) for the automated and / or manually assisted movement of the first drive unit (12) and / or the at least one second drive unit (13).

6. The method according to any one of claims 1 to 5, characterized in that, during the starting stage (15) of the air jet loom (1), the shuttle opening closing angle (FSW) is adjusted to the loom angle (WMW) located after the weft yarn (6) has been beaten with the reed.

7. The method according to any one of claims 1 to 6, characterized in that, during the stop phase (16) of the air jet loom (1), the shuttle opening closing angle (FSW) is adjusted to the loom angle (WMW) located before the weft yarn (6) is beaten by the reed.

8. The method according to any one of claims 1 to 7, characterized in that the adjustment of the shuttle opening closing angle (FSW) is performed while the air jet loom (1) is in operation.

9. The method according to any one of claims 6 to 8, characterized in that the shuttle closing angle (FSW) is shifted to a value to be adjusted via an intermediate value during the starting stage (15) and / or stopping stage (16).

10. The method according to any one of claims 1 to 9, characterized in that the shuttle closure angle (FSW) is adjusted earlier for the warp threads (3) in the edge region (KB) of the woven fabric (17) to be manufactured than for the warp threads (3) in the central region (MB) of the woven fabric (17) to be manufactured.

11. The method according to any one of claims 1 to 10, characterized in that an individual shuttle closure angle (FSW) is adjusted for each weft insertion according to the tissue pattern.

12. An air jet loom (1) is provided with a shuttle opening forming means (2) for opening and closing the shuttle opening according to the weave pattern, an air nozzle (5) distributed across the weaving width (WB) for inserting the weft yarn (6), a reed (7) for beating the inserted weft yarn (6), the air jet loom (1) has a first drive device (12) for driving the reed (7) which defines the loom angle (WMW), and at least one second drive device (13) for driving the shuttle opening forming means (2), and a control unit (14) for controlling the drive devices (12, 13) and for adjusting the shuttle opening closing angle (FSW) with respect to the loom angle (WMW), in the air jet loom (1), The control unit (14) is formed to carry out the method according to any one of claims 1 to 11, characterized in that it is an air jet loom (1).

13. The air jet loom (1) according to claim 12, characterized in that the shuttle-forming means (2) includes a plurality of heddles.

14. The air jet loom (1) according to claim 13, characterized in that the air jet loom (1) includes a separate drive device for each heddle.

15. The air jet loom (1) according to claim 12, characterized in that the shuttle opening forming means (2) includes a plurality of harness cords.

16. The air jet loom (1) according to claim 15, characterized in that it includes a separate drive device for each harness cord.

17. A computer program that, when implemented by the control unit (14) of an air jet loom (1), causes the control unit (14) to implement the method described in any one or more of claims 1 to 11.

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