Air-jet loom

Abstract

To provide an air-jet loom capable of assisting a weft insertion operation without making the air injection time of a sub-nozzle longer or increasing the number of times of air injections of a sub-nozzle.SOLUTION: An air-jet loom 1 comprises a weft insertion device 10 which repeatedly performs a weft insertion operation of inserting the weft Y into the warp shed by air injection from a main nozzle 22 and a plurality of sub-nozzles 15a, an assist nozzle 15b which is located within a weaving width TL and performs the air injection so as to apply a tractive force in the weft insertion direction X to the weft Y, and a control device 16 which controls the air injections from the main nozzle 22, the plurality of sub-nozzles 15a, and the assist nozzle 15b. The control device 16 can execute an assist control for ejecting air from the assist nozzle 15b, in addition to a relay control for sequentially ejecting air in order from the sub-nozzle 15a located on the upstream side in the weft insertion direction X to the sub-nozzle 15a located on the downstream side in the weft insertion operation performed each time.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an air jet loom. [Background technology]

[0002] The air jet loom described in Patent Document 1 includes a weft insertion device and a control device. The weft insertion device repeatedly inserts a weft into a warp shed by jetting air from a main nozzle and multiple sub-nozzles to make the weft fly. If the direction in which the weft flies when it is inserted into the warp shed is defined as the weft insertion direction, the multiple sub-nozzles are aligned in the weft insertion direction. The control device controls the air jets from the main nozzle and the multiple sub-nozzles.

[0003] In the air jet loom described in Patent Document 2, the control device sequentially injects air from the sub-nozzle located upstream in the weft insertion direction to the sub-nozzle located downstream. The control device also injects air from one of the sub-nozzles simultaneously with the sub-nozzle located furthest downstream in the weft insertion direction. In other words, one of the sub-nozzles injects air twice in one weft insertion operation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2014-500914 [Patent Document 2] Japanese Patent Application Publication No. 6-108345 Summary of the Invention [Problem to be solved by the invention]

[0005] When a weft thread is inserted, if the weft thread's flight speed is slow, the tip of the weft thread will reach the final destination position later than it should. In this case, the warp shed will close before the weft thread reaches the final destination position, which may cause the machine to stop due to poor weft transport. In addition, after the tip of the weft thread reaches the final destination position, the weft thread may become loose on the upstream side in the weft insertion direction. If the warp shed closes with the weft thread loose, i.e., when the weft thread is not fully stretched, stripes may appear in the woven fabric, which may result in a defective woven fabric. For this reason, it is preferable to assist the weft insertion operation by speeding up the weft thread's flight or suppressing the weft thread's looseness.

[0006] One way to assist the weft insertion operation is to lengthen the air injection time of the sub-nozzle. However, if the air injection time of the sub-nozzle is set long to increase the weft transport force, it may be difficult to further extend the air injection time. Another way to assist the weft insertion operation is to increase the number of times that the sub-nozzle injects air. However, in this case, the number of times that the valve that switches between injecting and stopping air from the sub-nozzle is operated increases, shortening the life of the valve. [Means for solving the problem]

[0007] The air jet loom for solving the above problem includes a weft insertion device that repeatedly performs a weft insertion operation in which a weft wound on a storage drum is unwound by retracting a weft locking pin, and the unwound weft is made to fly through a passage in a reed by air jets from a main nozzle and a plurality of sub-nozzles, thereby inserting the weft into a warp shed; and a control device that controls the air jets from the main nozzle and the plurality of sub-nozzles, wherein the direction in which the weft yarn flies when the weft yarn is inserted into the warp shed is defined as a weft insertion direction, and the plurality of sub-nozzles are aligned in the weft insertion direction, and the control device The device is an air jet loom that performs relay control to sequentially spray air from the sub-nozzle located upstream in the weft insertion direction to the sub-nozzle located downstream in each weft insertion operation, and is characterized in that, in addition to the multiple sub-nozzles, it is provided with an assist nozzle within the weaving width that sprays air to impart a traction force to the weft yarn in the weft insertion direction and whose air spray is controlled by the control device, and the control device is capable of performing assist control to spray air from the assist nozzle in each weft insertion operation, in addition to the relay control.

[0008] According to the above configuration, in the assist control, air is injected by the assist nozzle, which is a nozzle different from the sub-nozzle that injects air in the relay control, and therefore, it is possible to assist the weft insertion operation without increasing the air injection time or the number of air injections by the sub-nozzle.

[0009] The air jet loom may include a weft detection unit that detects information regarding the flight of the weft thread before the weft thread reaches a final destination position, and the control device may perform a delay estimation to estimate a delay in the flight of the weft thread based on the detection result from the weft detection unit, and perform the assist control when a delay in the flight of the weft thread is estimated.

[0010] According to the above configuration, when the control device estimates a delay in the flight of the weft yarn, air is injected from the assist nozzle. Therefore, when the flight of the weft yarn is delayed or a delay is predicted, the flight of the weft yarn is accelerated by the air injected from the assist nozzle. Therefore, the flight of the weft yarn can be accelerated without increasing the air injection time from the sub-nozzle or the number of air injections from the sub-nozzle.

[0011] In the air jet loom, the weft detection unit may be a balloon sensor that detects the weft unwound from the storage drum. According to the above configuration, the control device can estimate the delay in the flight of the weft yarn by using the balloon sensor required for the flight of the weft yarn, without increasing the number of parts.

[0012] In the air jet loom, the weft detection section may be a state detection sensor that detects a state of the weft before weft insertion. According to the above configuration, the flight speed of the inserted weft yarn can change depending on the state of the weft yarn, but the flight delay of the weft yarn can be estimated according to the state of the weft yarn, thereby improving the accuracy of the estimation of the flight delay of the weft yarn by the control device.

[0013] In the air jet loom, the weft detection unit may be an intermediate arrival time detection sensor that detects an intermediate arrival time when a tip of the inserted weft reaches a predetermined position upstream of the final arrival position in the weft insertion direction.

[0014] According to the above configuration, the intermediate arrival time detection sensor can detect the tip of the inserted weft yarn, so that the position of the weft yarn in the weft insertion direction can be detected more accurately, thereby improving the accuracy of the estimation of the weft yarn flight delay performed by the control device.

[0015] In the air jet loom, the assist nozzle may be located upstream in the weft insertion direction within the weaving width. According to the above configuration, compared to when the assist nozzle injects air downstream in the weft insertion direction within the weaving width, when the assist nozzle injects air upstream in the weft insertion direction within the weaving width, the range over which the air acts on the weft is larger, and the effect of accelerating the flight of the weft yarn by the assist nozzle is greater. Note that in the present invention, "the upstream side in the weft insertion direction within the weaving width" refers to the region from the center of the weaving width to the weaving end on the upstream side in the weft insertion direction.

[0016] In the air jet loom, the assist nozzle may be located only on the upstream side in the weft insertion direction within the weaving width. In an air jet loom, the weaving width is changed on the downstream side of the weft insertion direction with respect to the upstream side of the weft insertion direction. When changing the weaving width, if the assist nozzle is located on the downstream side of the weft insertion direction within the weaving width, it is necessary to adjust the position of the assist nozzle according to the weaving width. However, as in the above configuration, if the assist nozzle is located only on the upstream side of the weft insertion direction within the weaving width, there is no need to adjust the position of the assist nozzle even when the weaving width is changed.

[0017] In the air jet loom, the assist nozzle may be located upstream in the weft insertion direction within the weaving width, and the control device may perform the assist control after the tip of the weft yarn reaches a final arrival position.

[0018] According to the above configuration, air is injected from the assist nozzle after the tip of the weft yarn reaches the final destination position. Therefore, after the tip of the weft yarn reaches the final destination position, the air injected from the assist nozzle stretches the weft yarn in the weft insertion direction, thereby suppressing loosening of the weft yarn. Therefore, loosening of the weft yarn can be suppressed without increasing the air injection time from the sub-nozzle or the number of air injections from the sub-nozzle.

[0019] In addition, since the assist nozzle is located upstream in the weft insertion direction within the weaving width, air can be sprayed to the portion of the weft yarn that is located upstream in the weft insertion direction within the weaving width and that is prone to loosening, thereby effectively suppressing loosening of the weft yarn.

[0020] The air jet loom may have a stretch nozzle that is positioned downstream of the final arrival position in the weft insertion direction and that injects air into the weft yarn, and the air injection from the stretch nozzle is provided with a tensioning device controlled by the control device, and the control device may start air injection from the assist nozzle at the same time as starting air injection from the stretch nozzle.

[0021] According to the above configuration, the weft yarn is stretched simultaneously by both the air jetted from the assist nozzle and the air jetted from the stretch nozzle, so that loosening of the weft yarn can be further suppressed. Also, by synchronizing the jet start timing from the assist nozzle with the jet start timing from the other nozzles, it becomes easier to control the jet start timing.

[0022] In the air jet loom, the control device may stop air jetting from the assist nozzle at the same time as stopping air jetting from the sub-nozzle located most downstream in the weft insertion direction within the weaving width.

[0023] According to the above configuration, damage to the weft yarn can be reduced compared to the case where air injection from the assist nozzle continues even after air injection from the sub-nozzle located at the most downstream side in the weft insertion direction within the weaving width is stopped. Also, by matching the injection stop timing from the assist nozzle with the injection stop timing from the other nozzles, it becomes easier to control the injection stop timing. Effect of the Invention

[0024] According to this invention, it is possible to assist the weft insertion operation without increasing the time for which air is sprayed by the sub-nozzles or the number of times that air is sprayed by the sub-nozzles. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a schematic diagram showing a weft insertion device in an air jet loom according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view showing a weft insertion device in the air jet loom according to the first embodiment. [Diagram 3] FIG. 3(a) is a timing chart showing the opening and closing timings of the main valve and the sub-valve in the first embodiment, and FIG. 3(b) is a timing chart showing the opening and closing timings of the assist valve in the first embodiment. [Figure 4] FIG. 4 is a schematic diagram showing an air jet loom according to the second embodiment. [Diagram 5] FIG. 5(a) is a timing chart showing the opening and closing timings of the main valve, the sub valve, and the stretch valve in the second embodiment, and FIG. 5(b) is a timing chart showing the opening and closing timings of the assist valve in the second embodiment. [Figure 6] FIG. 6(a) is a timing chart showing the opening and closing timings of the main valve and the sub-valve in the modified example, and FIG. 6(b) is a timing chart showing the opening and closing timings of the assist valve in the modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] [First embodiment] A first embodiment of an air jet loom will now be described with reference to the drawings. In the following description, the direction in which a weft yarn travels when being inserted into a warp shed is referred to as a weft insertion direction.

[0027] <Air jet loom> 1, the air jet loom 1 includes a weft insertion device 10, a plurality of assist nozzles 15b, a final arrival time detection sensor 40, a balloon sensor 19, a state detection sensor 45, an intermediate arrival time detection sensor 41, and a control device 16. The balloon sensor 19 in this embodiment corresponds to a weft detection unit.

[0028] <Weft Insertion Device> As shown in FIG. 1, the weft insertion device 10 includes a weft insertion nozzle 11, a yarn supplying section 12, a weft length measuring and storing device 13, a reed 14, a plurality of sub-nozzles 15a, a brake 23, and a control device 16.

[0029] The yarn supplying unit 12 is disposed upstream of the weft insertion nozzle 11 in the weft insertion direction X. The weft Y of the yarn supplying unit 12 is drawn out by rotation of a winding arm (not shown) of the weft length measuring and storing device 13, and is stored in a wound state on the storage drum 17. The weft insertion nozzle 11 includes a tandem nozzle 21 that draws out the weft Y from the storage drum 17, and a weft insertion main nozzle 22 that inserts the weft Y into the reed passage 14a of the reed 14. The tandem nozzle 21, the brake 23, the weft length measuring and storing device 13, and the yarn supplying unit 12 are fixed, for example, to a bracket or the like attached to a frame (not shown) or a floor surface of the air jet loom 1.

[0030] As shown in FIG. 2, the main nozzle 22, the sub-nozzles 15a, the assist nozzles 15b, and the reed 14 are disposed on a slay 24. Note that FIG. 2 illustrates only one of the sub-nozzles 15a and one of the assist nozzles 15b. The main nozzle 22, the sub-nozzles 15a, the assist nozzles 15b, and the reed 14 are swung back and forth together with the slay 24 in the front-rear direction of the air jet loom 1. Each of the sub-nozzles 15a and each of the assist nozzles 15b is fixed to the slay 24 via a support block 25. The sub-nozzles 15a and each of the assist nozzles 15b are positioned within the weaving width TL (see FIG. 1). Each of the sub-nozzles 15a and each of the assist nozzles 15b can enter and exit the warp shed between the rows of warp threads T within the weaving width TL as the slay 24 sways.

[0031] The reed 14 is configured by arranging a plurality of reed dents 14c, each having a guide recess 14b, in a row in the weft insertion direction X. The reed passage 14a is formed by the guide recesses 14b of the plurality of reed dents 14c.

[0032] 1, the weft length measuring and storing device 13 includes a weft locking pin 18. The weft locking pin 18 is disposed around the storage drum 17. The weft locking pin 18 is electrically connected to the control device 16.

[0033] The weft insertion device 10 unwinds the weft Y wound on the storage drum 17 by retracting the weft locking pin 18. In detail, the weft locking pin 18 unwinds the weft Y stored on the storage drum 17 by retracting the weft locking pin 18 at a preset loom rotation angle. The time when the weft locking pin 18 unwinds the weft Y is the weft insertion start time.

[0034] When the control device 16 returns the weft locking pin 18 to the position before it was unwound, the weft locking pin 18 locks the weft Y unwound from the storage drum 17, thereby completing the weft insertion. The point in time at which the weft locking pin 18 locks the weft Y is set according to the number of windings required to store the weft Y of a length equivalent to the weaving width TL in the storage drum 17.

[0035] The brake 23 is disposed downstream of the storage drum 17 in the weft insertion direction X. The brake 23 brakes the flying weft Y before the weft insertion of the weft Y is completed. The brake 23 brakes the weft Y flying at high speed to reduce the flying speed of the weft Y. This reduces the flying speed of the weft Y before the weft locking pin 18 locks onto the weft Y. As a result, the impact acting on the weft Y when the weft locking pin 18 locks onto the weft Y at the time when the tip of the weft Y reaches the final arrival position Pw, which is the weft insertion end, is reduced.

[0036] The main nozzle 22 is connected to a main valve 22v via a pipe 22a. The main valve 22v is connected to a main air tank 26 via a pipe 22b. The tandem nozzle 21 is connected to a tandem valve 21v via a pipe 21a. The tandem valve 21v is connected to a main air tank 26 shared with the main valve 22v via a pipe 21b. The tandem valve 21v may be connected to an air tank other than the main air tank 26. The main air tank 26 is connected to a common air compressor 31 installed in the weaving factory. The main air tank 26 stores compressed air supplied from the air compressor 31.

[0037] When the main valve 22v is open, the main nozzle 22 sprays compressed air. When the main valve 22v is closed, the main nozzle 22 does not spray compressed air. In this way, spraying or stopping of compressed air from the main nozzle 22 is switched by opening or closing the main valve 22v. When the tandem valve 21v is open, the tandem nozzle 21 sprays compressed air. When the tandem valve 21v is closed, the tandem nozzle 21 does not spray compressed air. In this way, spraying or stopping of compressed air from the tandem nozzle 21 is switched by opening or closing the tandem valve 21v.

[0038] The sub-nozzles 15a and the assist nozzles 15b are arranged in the weft insertion direction X within the weaving width TL. In FIG. 1, for convenience, the sub-nozzles 15a are shown as white rectangles, and the assist nozzles 15b are shown as black rectangles. The sub-nozzles 15a are divided into, for example, nine nozzle groups. Each nozzle group includes two sub-nozzles 15a. In the following description, the nine nozzle groups are referred to as the first nozzle group, the second nozzle group, the third nozzle group, the fourth nozzle group, the fifth nozzle group, the sixth nozzle group, the seventh nozzle group, the eighth nozzle group, and the ninth nozzle group from the upstream side to the downstream side in the weft insertion direction X. A total of three assist nozzles 15b are provided between the two sub-nozzles 15a of the first nozzle group, between the first nozzle group and the second nozzle group, and between the two sub-nozzles 15a of the second nozzle group.

[0039] The assist nozzle 15b is located on the upstream side of the weft insertion direction X within the weaving width TL. The "upstream side of the weft insertion direction X within the weaving width TL" refers to the region TLa from the center TLc of the weaving width TL to the weaving end TLe on the upstream side of the weft insertion direction X. In this embodiment, each assist nozzle 15b is provided between the four sub-nozzles 15a located on the most upstream side among all the sub-nozzles 15a arranged in the weft insertion direction X. Therefore, three sets are provided in which the sub-nozzles 15a and the assist nozzle 15b are arranged in this order from the upstream side of the weft insertion direction X. All the downstream sides of these sets in the weft insertion direction X are composed of the sub-nozzles 15a. In the air jet loom 1 in this embodiment, the assist nozzle 15b is located only on the upstream side of the weft insertion direction X within the weaving width TL.

[0040] One sub-valve 32a is connected to each nozzle group of the sub-nozzles 15a. Therefore, the weft insertion device 10 has nine sub-valves 32a. One assist valve 32b is connected to three assist nozzles 15b. Therefore, the weft insertion device 10 has one assist valve 32b. For convenience, in Fig. 1, the sub-valves 32a are shown as open rectangles, and the assist valves 32b are shown as filled rectangles.

[0041] In each group of sub-nozzles 15a, the sub-nozzles 15a and the sub-valves 32a are connected to each other via a sub-pipe 33a. In each of the three assist nozzles 15b, the assist nozzles 15b and the assist valves 32b are connected to each other via an assist pipe 33b. Each of the sub-valves 32a and each of the assist valves 32b are connected to a common sub-air tank 34. Each of the assist valves 32b may be connected to an air tank other than the sub-air tank 34.

[0042] When the sub-valve 32a is open, the sub-nozzle 15a sprays air. The sub-nozzle 15a sprays air so as to impart a traction force in the weft insertion direction X to the weft yarn Y. When the sub-valve 32a is closed, the sub-nozzle 15a does not spray air. In this way, spraying of air from the sub-nozzle 15a is switched on and off by opening and closing the sub-valve 32a.

[0043] When the assist valve 32b is open, the assist nozzle 15b injects air. The assist nozzle 15b injects air so as to impart a traction force in the weft insertion direction X to the weft Y. Therefore, the air jet loom 1 is provided with the assist nozzle 15b that injects air so as to impart a traction force in the weft insertion direction X to the weft Y, in addition to the multiple sub-nozzles 15a. When the assist valve 32b is closed, the assist nozzle 15b does not inject air. In this way, the injection of air from the assist nozzle 15b can be switched between opening and closing by opening and closing the assist valve 32b.

[0044] The main valve 22v, the tandem valve 21v, the sub-valve 32a, and the assist valve 32b are electrically connected to the control device 16. The control device 16 controls the operations of the main valve 22v, the sub-valve 32a, and the assist valve 32b, causing air to be sprayed from the main nozzle 22, the multiple sub-nozzles 15a, and the multiple assist nozzles 15b. Thus, the control device 16 controls the air spraying from the main nozzle 22, the multiple sub-nozzles 15a, and the multiple assist nozzles 15b.

[0045] The weft yarn Y is inserted into the warp shed through the reed passage 14a by air jets from the main nozzle 22 and the sub-nozzles 15a. The weft insertion device 10 performs a weft insertion operation in which the unwound weft yarn Y is made to fly through the reed passage 14a of the reed 14 by air jets from the main nozzle 22 and the sub-nozzles 15a, and is inserted into the warp shed. The weft insertion device 10 repeats this weft insertion operation.

[0046] Specifically, when inserting the weft yarn Y, the control device 16 outputs an operation command signal to the main valve 22v and the tandem valve 21v. Also, when inserting the weft yarn Y, the control device 16 outputs an operation command signal to each sub-valve 32a. Then, the weft yarn Y receives compressed air jetted from the main nozzle 22 and starts flying, and after starting to fly, receives compressed air jetted from the multiple sub-nozzles 15a and flies to the final arrival position Pw.

[0047] <Various sensors> The final arrival time detection sensor 40 is disposed at a position facing the downstream side of the reed passage 14a in the weft insertion direction X. The final arrival time detection sensor 40 is disposed outside the weaving width TL. The final arrival time detection sensor 40 is disposed so that the tip position of the weft Y corresponding to the weft storage length of n turns of the storage drum 17 becomes the detection position of the final arrival time detection sensor 40 when the weft Y is normally inserted. The final arrival time detection sensor 40 is electrically connected to the control device 16. When the final arrival time detection sensor 40 detects the tip of the weft Y, it outputs a weft detection signal. This weft detection signal is an arrival signal of the weft Y to the final arrival position Pw. Based on the weft detection signal outputted by the final arrival time detection sensor 40, the control device 16 recognizes the final arrival time Tw when the tip of the weft Y reaches the detection position of the final arrival time detection sensor 40. Therefore, the final arrival time detection sensor 40 detects the final arrival time Tw when the tip of the inserted weft Y reaches the final arrival position Pw. The final arrival time detection sensor 40 outputs a weft detection signal to the control device 16 for the control device 16 to recognize the final arrival time Tw.

[0048] The balloon sensor 19 detects the weft Y unwound from the storage drum 17. Therefore, the balloon sensor 19 as a weft detection unit detects information regarding the flight of the weft Y before it reaches the final arrival position Pw. The balloon sensor 19 is included in the weft length measuring and storing device 13. The balloon sensor 19 is disposed around the storage drum 17. The balloon sensor 19 is electrically connected to the control device 16.

[0049] When the balloon sensor 19 detects the weft Y unwound from the storage drum 17, it outputs a weft unwinding signal to the control device 16. When the control device 16 receives the weft unwinding signal a preset number of times, it returns the weft locking pin 18 to the position before unwinding. As a result, the weft locking pin 18 locks the weft Y unwound from the storage drum 17, and the weft insertion is completed.

[0050] The state detection sensor 45 detects the state of the weft Y supplied from the yarn supplying section 12. The state detection sensor 45 is located between the yarn supplying section 12 and the storage drum 17 in the weft insertion direction X. That is, the state detection sensor 45 is located upstream of the storage drum 17 in the weft insertion direction X. In contrast, the weft Y is inserted into the warp shed downstream of the storage drum 17 in the weft insertion direction X. Therefore, the state detection sensor 45 detects the state of the weft Y before it is inserted. In other words, the state detection sensor 45 detects information regarding the flight of the weft Y before it reaches the final arrival position Pw.

[0051] The state of the weft yarn Y detected by the state detection sensor 45 is at least one yarn parameter selected from the group consisting of yarn mass, yarn diameter, yarn density, yarn surface structure, yarn fluff, and yarn material. These states of the weft yarn Y can affect the flight of the weft yarn Y when the weft yarn Y is inserted by jetting air to make it fly.

[0052] The state detection sensor 45 is electrically connected to the control device 16. When the state detection sensor 45 detects the state of the weft yarn Y before weft insertion, it outputs a state detection signal to the control device 16. Based on this state detection signal, the control device 16 recognizes the state of the weft yarn Y.

[0053] The intermediate arrival time detection sensor 41 is disposed upstream of the final arrival time detection sensor 40 in the weft insertion direction X, facing the reed passage 14a within the weaving width TL. In this embodiment, the intermediate arrival time detection sensor 41 is disposed closer to the main nozzle 22 than the center TLc of the weaving width TL. The intermediate arrival time detection sensor 41 is disposed so that the tip position of the weft Y, which corresponds to a length shorter than the weft storage length of n turns of the storage drum 17, becomes the detection position of the intermediate arrival time detection sensor 41 when the weft Y is inserted. Therefore, the intermediate arrival time detection sensor 41 detects information regarding the flight of the weft Y before it reaches the final arrival position Pw.

[0054] The intermediate arrival time detection sensor 41 is electrically connected to the control device 16. When the intermediate arrival time detection sensor 41 detects the tip of the weft Y, it outputs a weft detection signal. Based on the weft detection signal output by the intermediate arrival time detection sensor 41, the control device 16 recognizes the intermediate arrival time Ti at which the tip of the weft Y reaches the detection position of the intermediate arrival time detection sensor 41. Therefore, the intermediate arrival time detection sensor 41 detects the intermediate arrival time Ti at which the tip of the weft Y reaches a predetermined position Pi upstream of the final arrival position Pw in the weft insertion direction X.

[0055] <Control device details> The control device 16 includes a processor and a storage unit (not shown). The processor is, for example, a central processing unit (CPU), a graphics processing unit (GPU), or a digital signal processor (DSP). The storage unit includes a random access memory (RAM) and a read only memory (ROM). The storage unit stores program codes or instructions configured to cause the processor to execute processes. The storage unit, i.e., the computer readable medium, includes any available medium accessible by a general-purpose or special-purpose computer. The control device 16 may be configured by a hardware circuit such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA). The control device 16, which is a processing circuit, may include one or more processors operating according to a computer program, one or more hardware circuits such as an ASIC or an FPGA, or a combination thereof.

[0056] <Relay control> The control device 16 performs relay control for the multiple sub-nozzles 15a in each weft insertion operation to sequentially inject air from the sub-nozzle 15a located upstream to the sub-nozzle 15a located downstream in the weft insertion direction X. Therefore, the sub-nozzle 15a is the nozzle that injects air in the relay control.

[0057] In the relay control of this embodiment, the control device 16 causes each nozzle group to inject air in the order of the first nozzle group, the second nozzle group, the third nozzle group, the fourth nozzle group, the fifth nozzle group, the sixth nozzle group, the seventh nozzle group, the eighth nozzle group, and the ninth nozzle group. For example, the control device 16 causes air injection from the sub-nozzles 15a of the first nozzle group to start at the same time as starting air injection from the main nozzles 22. The control device 16 may cause air injection from the sub-nozzles 15a of the first nozzle group to start after starting air injection from the main nozzles 22.

[0058] In this embodiment, the control device 16 causes air to be ejected from the main nozzle 22 and the sub-nozzles 15a based on the final arrival time Tw, which is the detection result from the final arrival time detection sensor 40. For example, the control device 16 adjusts the flight condition C so that the final arrival time Tw, which is the detection result from the final arrival time detection sensor 40, approaches a target value.

[0059] For example, when the final arrival time Tw detected by the final arrival time detection sensor 40 is later than the original time, the control device 16 sets the flying condition C to be adopted next time so that the flying speed is faster so that the final arrival time Tw at the time of the next weft insertion of the weft Y becomes the original time. For example, when the final arrival time Tw detected by the final arrival time detection sensor 40 is earlier than the original time, the control device 16 sets the flying condition C to be adopted next time so that the flying speed is slower so that the final arrival time Tw at the time of the next weft insertion of the weft Y becomes the original time.

[0060] The memory unit of the control device 16 stores a plurality of conditions with different timings for air injection from the main nozzle 22 and the sub-nozzle 15a as the flight condition C. These conditions are conditions with different flight speeds of the weft Y, and are set in advance through experiments or the like. Therefore, the control device 16 controls the air injection from the main nozzle 22 and the sub-nozzle 15a according to the flight condition C. The control device 16 optimizes the final arrival time Tw at the time of the next weft insertion of the weft Y by setting the flight condition C based on the final arrival time Tw.

[0061] In addition, in all flight conditions C stored in the memory unit of the control device 16, the opening time of the main nozzle 22 is a predetermined fixed time. In all flight conditions C stored in the memory unit of the control device 16, the opening time of the sub-nozzle 15a is a predetermined fixed time. Of all flight conditions C stored in the memory unit of the control device 16, in at least one flight condition C, the opening time of the main nozzle 22 may be different from the other flight conditions C. Of all flight conditions C stored in the memory unit of the control device 16, in at least one flight condition C, the opening time of the sub-nozzle 15a may be different from the other flight conditions C.

[0062] <Assist control> In addition to the relay control, the control device 16 can execute assist control for injecting air from the assist nozzle 15b during each weft insertion operation. Therefore, the assist nozzle 15b is a nozzle that injects air during the assist control. The assist control is performed to assist the weft insertion operation. The assist control in this embodiment is performed to speed up the flight of the weft Y when the flight of the weft Y is delayed during the weft insertion.

[0063] In this embodiment, the control device 16 performs delay estimation to estimate the delay in the flight of the weft yarn Y based on the detection result from the balloon sensor 19 as the weft detection unit. In detail, the control device 16 judges whether the time when the number of weft unwinding signals input from the balloon sensor 19 reaches a predetermined number is later than a predetermined time point. The above-mentioned predetermined number may be set to the number of times when the tip position of the weft yarn Y reaches a predetermined position upstream of the detection position of the final arrival time detection sensor 40 in the weft insertion direction X when the weft yarn Y is inserted. In this case, the above-mentioned predetermined time point is set to the time when the tip position of the weft-inserted weft yarn Y reaches the above-mentioned predetermined position. Therefore, the control device 16 estimates the presence or absence of a delay in the flight of the weft yarn Y by judging whether the time when the number of weft unwinding signals input from the balloon sensor 19 reaches a predetermined number is later than the predetermined time point. If the time when the number of weft unwinding signals input from the balloon sensor 19 reaches a predetermined number is later than the predetermined time point, the control device 16 estimates that a delay in the flight of the weft yarn Y has occurred.

[0064] The control device 16 judges whether to execute assist control based on the result of delay estimation. The control device 16 executes assist control when it estimates a delay in the flight of the weft yarn Y. That is, the control device 16 causes air injection from the assist nozzle 15b when it estimates a delay in the flight of the weft yarn Y. The control device 16 does not execute assist control when it estimates that the flight of the weft yarn Y is not delayed. That is, the control device 16 does not cause air injection from the assist nozzle 15b when it estimates that the flight of the weft yarn Y is not delayed. Therefore, in the weft insertion operation that is performed multiple times, when the flight of the weft yarn Y is delayed, relay control and assist control are performed, and when the flight of the weft yarn Y is not delayed, only relay control is performed without assist control.

[0065] As a result, when the flight of the weft yarn Y is delayed, the control device 16 injects air from the assist nozzle 15b in addition to the air injection from the main nozzle 22 and the sub-nozzles 15a. The timing at which air injection from the assist nozzle 15b starts under the assist control may be different from the timing at which air injection from the main nozzle 22 and the sub-nozzles 15a starts under the relay control, for example.

[0066] [Operation of the first embodiment] The operation of the above embodiment will be described. Fig. 3(a) is a timing chart showing an example of the opening and closing timing of the main valve 22v and the sub-valve 32a in relay control, i.e., the jetting timing of the main nozzle 22 and the sub-nozzle 15a. Fig. 3(b) is a timing chart showing an example of the opening and closing timing of the assist valve 32b in assist control, i.e., the jetting timing of the assist nozzle 15b. Fig. 3(a) and Fig. 3(b) show the jetting timing of the main nozzle 22, the sub-nozzle 15a, and the assist nozzle 15b in one weft insertion operation.

[0067] As shown in Fig. 3(a), line M represents the ejection timing of the main nozzles 22. Lines E1, E2, E3, and E4 represent the ejection timing of the first nozzle group, the second nozzle group, the third nozzle group, and the fourth nozzle group of the sub-nozzles 15a, respectively. Note that in Fig. 3(a), the ejection timing of the fifth to ninth nozzle groups of the sub-nozzles 15a are omitted from the illustration.

[0068] Timing T1 indicates the timing at which the weft Y stored in the storage drum 17 starts to be unwound as the weft locking pin 18 retreats. Timing M1 indicates the timing at which the main nozzle 22 starts to jet. Timings E2s, E3s, and E4s indicate the timing at which the sub-nozzles 15a in the second nozzle group, the third nozzle group, and the fourth nozzle group start to jet, respectively. Timing M2 indicates the timing at which the main nozzle 22 stops to jet. Timings E1e, E2e, and E3e indicate the timing at which the sub-nozzles 15a in the first nozzle group, the second nozzle group, and the third nozzle group stop to jet, respectively. Note that the timing at which the sub-nozzles 15a in the fourth nozzle group stops to jet is not shown. Line D1 indicates an example of the flying state of the weft Y.

[0069] As shown in FIG. 3(b), the timing T2 is the timing at which the control device 16 judges whether the time when the number of weft unwinding signals input from the balloon sensor 19 to the control device 16 reaches a predetermined number is later than a predetermined time. That is, the timing T2 is the timing at which the control device 16 performs delay estimation to estimate the delay in the flight of the weft Y based on the detection result from the balloon sensor 19 as a weft detection unit. At this timing T2, if the time when the number of weft unwinding signals input from the balloon sensor 19 reaches a predetermined number is later than the predetermined time, the control device 16 estimates that a delay in the flight of the weft Y has occurred. Then, the control device 16 performs assist control to cause air injection from the assist nozzle 15b. The timing T3 represents the opening timing of the assist valve 32b, that is, the injection start timing of the three assist nozzles 15b. The timing T4 represents the closing timing of the assist valve 32b, that is, the injection stop timing of the three assist nozzles 15b.

[0070] The control device 16 can execute assist control for injecting air from the assist nozzle 15b in each weft insertion operation in addition to relay control. The control device 16 of this embodiment executes assist control when it is estimated that the flight of the weft Y is delayed. That is, when the flight of the weft Y is delayed, the control device 16 executes air injection from the assist nozzle 15b by assist control in addition to air injection from the main nozzle 22 and the multiple sub-nozzles 15a by relay control. Therefore, when the relay control and the assist control are executed by the control device 16, the flight speed of the weft Y is increased by the amount of air injected from the assist nozzle 15b acting on the weft Y, compared to the case where the control device 16 executes only the relay control without executing the assist control.

[0071] [Effects of the first embodiment] According to the above embodiment, the following effects can be obtained. (1-1) In addition to the sub-nozzles 15a, the air jet loom 1 includes an assist nozzle 15b within the weaving width TL, which injects air to apply a traction force in the weft insertion direction X to the weft yarn Y and whose air injection is controlled by the control device 16. In each weft insertion operation, the control device 16 can execute, in addition to relay control, assist control to inject air from the assist nozzle 15b.

[0072] According to this configuration, in the assist control, air is injected by the assist nozzle 15b, which is a nozzle different from the sub-nozzle 15a that injects air in the relay control. Therefore, it is possible to assist the weft insertion operation without increasing the air injection time by the sub-nozzle 15a or the number of air injections by the sub-nozzle 15a.

[0073] (1-2) The control device 16 performs delay estimation to estimate a delay in the flight of the weft yarn Y based on the detection result from the balloon sensor 19 as a weft detection unit. When the control device 16 estimates a delay in the flight of the weft yarn Y, it performs assist control. According to this configuration, when a delay in the flight of the weft yarn Y is estimated by the control device 16, air is injected from the assist nozzle 15b. Therefore, when the flight of the weft yarn Y is delayed, the flight of the weft yarn Y is accelerated by the air injected from the assist nozzle 15b. Therefore, the flight of the weft yarn Y can be accelerated without increasing the air injection time by the sub-nozzle 15a or the number of air injections by the sub-nozzle 15a.

[0074] (1-3) The weft detection unit is a balloon sensor 19 that detects the weft Y unwound from the storage drum 17. Therefore, the control device 16 can estimate the delay in the flight of the weft Y by using the balloon sensor 19 required for flying the weft Y. Therefore, the control device 16 can estimate the delay in the flight of the weft Y without increasing the number of parts.

[0075] (1-4) The assist nozzle 15b is located on the upstream side of the weft insertion direction X within the weaving width TL. Therefore, compared to the case where the assist nozzle 15b injects air downstream of the weft insertion direction X within the weaving width TL, the range over which the air acts on the weft yarn Y is larger when the assist nozzle 15b injects air upstream of the weft insertion direction X within the weaving width TL, and the effect of the assist nozzle 15b in accelerating the flight of the weft yarn Y is greater.

[0076] (1-5) In the air jet loom 1, the assist nozzle 15b is located only on the upstream side of the weft insertion direction X within the weaving width TL. In the air jet loom 1, the weaving width TL is changed on the downstream side of the weft insertion direction X with respect to the upstream side of the weft insertion direction X. When changing the weaving width TL, if the assist nozzle 15b is located on the downstream side of the weft insertion direction X within the weaving width TL, it is necessary to adjust the position of the assist nozzle 15b according to the weaving width TL. However, if the assist nozzle 15b is located only on the upstream side of the weft insertion direction X within the weaving width TL as in the above embodiment, there is no need to adjust the position of the assist nozzle 15b even when the weaving width TL is changed.

[0077] [Second embodiment] Hereinafter, a second embodiment of the air jet loom will be described with reference to the drawings. Note that, regarding the configuration of the air jet loom, the description of the parts that have already been described in the first embodiment will be omitted.

[0078] As shown in Fig. 4, the air jet loom 1 is equipped with a tension applying device 50 that applies tension to the weft yarn Y. The tension applying device 50 has a stretch nozzle 51. The stretch nozzle 51 is located downstream of the final arrival position Pw in the weft insertion direction X. The stretch nozzle 51 is located downstream of the final arrival point detection sensor 40 in the weft insertion direction X. The stretch nozzle 51 is disposed on the slay 24. The stretch nozzle 51 and the slay 24 are integrally swung back and forth in the front-to-rear direction of the air jet loom 1.

[0079] The stretch nozzle 51 is connected to a stretch valve 52 via a stretch piping 53. The stretch valve 52 is connected to a stretch air tank 54. When the stretch valve 52 is open, the stretch nozzle 51 sprays air. When the stretch valve 52 is closed, the stretch nozzle 51 does not spray air. In this way, spraying of air from the stretch nozzle 51 can be switched between on and off by opening and closing the stretch valve 52.

[0080] The stretch valve 52 is electrically connected to the control device 16. The control device 16 controls the operation of the stretch valve 52, causing air to be sprayed from the stretch nozzle 51. Therefore, the control device 16 controls the air spray from the stretch nozzle 51. The control device 16 sprays air from the stretch nozzle 51 after the tip of the weft yarn Y reaches the final arrival position Pw. The control device 16 starts spraying air from the stretch nozzle 51, for example, at a time before the tip of the weft yarn Y reaches the position of the stretch nozzle 51 in the weft insertion direction X.

[0081] After the tip of the weft yarn Y reaches the final arrival position Pw, the stretch nozzle 51 injects air onto the portion of the weft yarn Y located downstream in the weft insertion direction X. This causes the portion of the weft yarn Y located downstream in the weft insertion direction X to be stretched by the air injected from the stretch nozzle 51, thereby suppressing slack in the weft yarn Y.

[0082] The control device 16 performs relay control in each weft insertion operation. The relay control is the same as that in the first embodiment, so a description thereof will be omitted. In addition to the relay control, the control device 16 performs assist control in each weft insertion operation, in which air is injected from the assist nozzle 15b. Therefore, the assist nozzle 15b is a nozzle that injects air in the assist control. The assist control is performed to assist the weft insertion operation. The assist control in this embodiment is performed to suppress the weft Y from loosening on the upstream side of the weft insertion direction X after the weft Y reaches the final arrival position Pw.

[0083] In this embodiment, the assist nozzle 15b is located upstream in the weft insertion direction X within the weaving width TL. In this embodiment, the control device 16 performs assist control after the weft Y reaches the final arrival position Pw. That is, the control device 16 injects air from the assist nozzle 15b after the weft Y reaches the final arrival position Pw. As a result, the assist nozzle 15b injects air onto a portion of the weft Y located upstream in the weft insertion direction X after the tip of the weft Y reaches the final arrival position Pw.

[0084] [Operation of the second embodiment] The operation of the above embodiment will be described. As shown in Fig. 5(a), lines E5, E6, E7, E8, and E9 respectively represent the injection timings of the fifth, sixth, seventh, eighth, and ninth sub-nozzle groups 15a under relay control. Timing E9e represents the injection stop timing of the sub-nozzles 15a in the ninth nozzle group. Line S represents the injection timing of the stretch nozzle 51. Timing Ss represents the opening timing of the stretch valve 52, i.e., the injection start timing of the stretch nozzle 51.

[0085] FIG. 5(b) shows the injection timing of the assist nozzle 15b in the assist control. As described above, the timing T3 represents the injection start timing of the assist nozzle 15b. In this embodiment, the timing T3 coincides with the timing Ss. That is, the assist nozzle 15b starts air injection at the same time as the stretch nozzle 51 starts air injection. The timing T4 represents the injection stop timing of the assist nozzle 15b. In this embodiment, the timing T4 coincides with the timing E9e. That is, the assist nozzle 15b stops air injection at the same time as the sub-nozzle 15a of the ninth nozzle group located at the most downstream side in the weft insertion direction X within the weaving width TL stops air injection.

[0086] In each weft insertion operation, the control device 16 performs an assist control to inject air from the assist nozzle 15b in addition to the relay control. In this embodiment, the control device 16 performs the assist control after the tip of the weft yarn Y reaches the final arrival position Pw. As a result, after the tip of the weft yarn Y reaches the final arrival position Pw, the weft yarn Y is stretched in the weft insertion direction X by the air injected from the assist nozzle 15b, so that the loosening of the weft yarn Y is suppressed.

[0087] [Effects of the second embodiment] According to the above embodiment, in addition to the effects (1-1) and (1-5) of the first embodiment, the following effects can be obtained.

[0088] (2-1) The assist nozzle 15b is located upstream in the weft insertion direction X within the weaving width TL. The control device 16 performs assist control after the tip of the weft yarn Y reaches the final arrival position Pw. According to this configuration, air is injected from the assist nozzle 15b after the tip of the weft yarn Y reaches the final arrival position Pw. Therefore, after the tip of the weft yarn Y reaches the final arrival position Pw, the weft yarn Y is stretched in the weft insertion direction X by the air injected from the assist nozzle 15b, thereby suppressing slackening of the weft yarn Y. Therefore, it is possible to suppress slackening of the weft yarn Y without increasing the air injection time by the sub-nozzle 15a or the number of air injections by the sub-nozzle 15a.

[0089] In addition, since the assist nozzle 15b is located upstream of the weft insertion direction X within the weaving width TL, it is possible to inject air to a portion of the weft Y that is prone to loosening and is located upstream of the weft insertion direction X within the weaving width TL. This makes it possible to effectively prevent the weft Y from loosening.

[0090] (2-2) The air jet loom 1 is equipped with a tensioning device 50. The tensioning device 50 is disposed downstream of the final arrival position Pw in the weft insertion direction X and has a stretch nozzle 51 that injects air into the weft yarn Y. The air injection from the stretch nozzle 51 is controlled by the control device 16. The control device 16 starts air injection from the stretch nozzle 51 and at the same time starts air injection from the assist nozzle 15b.

[0091] According to this configuration, the weft yarn Y is stretched simultaneously by both the air jetted from the assist nozzle 15b and the air jetted from the stretch nozzle 51, which further suppresses slack in the weft yarn Y. In addition, by matching the jet start timing from the assist nozzle 15b with the jet start timing from the other nozzles, it becomes easier to control the jet start timing.

[0092] (2-3) The control device 16 stops air injection from the sub-nozzle 15a located most downstream in the weft insertion direction X within the weaving width TL, and at the same time stops air injection from the assist nozzle 15b.

[0093] This configuration reduces damage to the weft yarn Y compared to a case where air injection from the assist nozzle 15b continues even after air injection from the sub-nozzle 15a located most downstream in the weft insertion direction X within the weaving width TL has been stopped. Also, by matching the injection stop timing from the assist nozzle 15b with the injection stop timing from the other nozzles, it becomes easier to control the injection stop timing.

[0094] (2-4) When the air injection time of the sub-nozzle 15a located upstream in the weft insertion direction X within the weaving width TL is increased in order to suppress slackening of the weft Y, the sub-nozzle 15a located upstream in the weft insertion direction X within the weaving width TL continues to inject air from immediately after the start of weft insertion until after the tip of the weft Y reaches the final arrival position Pw. This increases the amount of air injected by the sub-nozzle 15a located upstream in the weft insertion direction X within the weaving width TL. In contrast, in this embodiment, the sub-nozzle 15a located upstream in the weft insertion direction X within the weaving width TL only needs to inject air immediately after the start of weft insertion. This allows the amount of air injected by the sub-nozzle 15a located upstream in the weft insertion direction X within the weaving width TL to be reduced.

[0095] [Example of change] The embodiment can be modified as follows: The embodiment and the following modified examples can be combined with each other to the extent that there is no technical contradiction.

[0096] In the first embodiment, the control device 16 may perform delay estimation to estimate the delay in the flight of the weft yarn Y based on the detection result from the intermediate arrival time detection sensor 41. In this case, the intermediate arrival time detection sensor 41 corresponds to a weft detection unit that detects information about the flight of the weft yarn Y before it reaches the final arrival position Pw. In this modification, air is injected from each of the main nozzle 22, the sub-nozzle 15a, and the assist nozzle 15b, as in the example shown in Fig. 3(a) and Fig. 3(b). In this modification, the timing T2 shown in Fig. 3(b) is the timing at which the control device 16 performs delay estimation to estimate the delay in the flight of the weft yarn Y based on the detection result from the intermediate arrival time detection sensor 41 as the weft detection unit. If the control device 16 estimates that a delay in the flight of the weft yarn Y occurs at this timing T2, the control device 16 causes air to be injected from the assist nozzle 15b in the assist control.

[0097] According to the above modification, in addition to the advantages (1-1), (1-2), (1-4), and (1-5) in the first embodiment, the following advantages can be obtained. The weft detection unit is an intermediate arrival time detection sensor 41 that detects an intermediate arrival time Ti when the tip of the inserted weft Y reaches a predetermined position Pi upstream of the final arrival position Pw in the weft insertion direction X. Therefore, the intermediate arrival time detection sensor 41 can detect the tip of the inserted weft Y, and therefore can more accurately detect the position of the weft Y in the weft insertion direction X. This improves the accuracy of the estimation of the flight delay of the weft Y performed by the control device 16.

[0098] The state detection sensor 45 may be omitted from the air jet loom 1 in the above modified example. In the first embodiment, the control device 16 may perform delay estimation to estimate a delay in the flight of the weft yarn Y based on the detection result from the state detection sensor 45. In this case, the state detection sensor 45 corresponds to a weft detection unit that detects information about the flight of the weft yarn Y before it reaches the final arrival position Pw. In this modified example, as shown in FIG. 6, air is injected from each of the main nozzle 22, the sub-nozzle 15a, and the assist nozzle 15b. In the example shown in FIG. 6(a) and FIG. 6(b), the injection timing of the assist nozzle 15b is changed from the example shown in FIG. 3(a) and FIG. 3(b). In this modified example, the timing T2 shown in FIG. 6(b) is the timing at which the control device 16 performs delay estimation to estimate a delay in the flight of the weft yarn Y based on the detection result from the state detection sensor 45 as the weft detection unit. If the control device 16 estimates that a delay in the flight of the weft yarn Y occurs at this timing T2, the control device 16 causes air to be injected from the assist nozzle 15b in the assist control. That is, when the control device 16 predicts a delay in the flight of the weft yarn Y, air is injected from the assist nozzle 15b.

[0099] According to the above modification, in addition to the advantages (1-1), (1-2), (1-4), and (1-5) in the first embodiment, the following advantages can be obtained. The weft detection unit is a state detection sensor 45 that detects the state of the weft before it is inserted. Therefore, although the flight speed of the weft Y to be inserted may change depending on the state of the weft Y, it is possible to estimate the flight delay of the weft Y according to the state of the weft Y. Therefore, it is possible to improve the accuracy of the estimation of the flight delay of the weft Y performed by the control device 16.

[0100] The intermediate arrival time detection sensor 41 may be omitted from the air jet loom 1 in the above modified example. At least one of the state detection sensor 45 and the intermediate arrival time detection sensor 41 may be omitted from the air jet loom 1 in the above-described embodiment.

[0101] The intermediate arrival time detection sensor 41 may be disposed at the center TLc of the weaving width TL, or at a position away from the main nozzle 22 from the center TLc of the weaving width TL. In the first embodiment, the position of the assist nozzle 15b can be changed. For example, the assist nozzle 15b may be located downstream in the weft insertion direction X within the weaving width TL, or may be located at the center TLc of the weaving width TL in the weft insertion direction X. The "downstream side of the weft insertion direction X within the weaving width TL" refers to the region from the center TLc of the weaving width TL to the weaving end on the downstream side of the weft insertion direction X. The assist nozzle 15b may be located at two or more positions among the upstream side, the center TLc, and the downstream side of the weft insertion direction X within the weaving width TL.

[0102] In each embodiment, the number of sub-nozzles 15a included in the weft insertion device 10 can be changed as long as it is two or more. The number of assist nozzles 15b included in the weft insertion device 10 can be changed. The number of groups of sub-nozzles 15a included in the weft insertion device 10 can be changed. The number of sub-nozzles 15a included in one group can be changed. When the weft insertion device 10 has multiple assist nozzles 15b, the multiple assist nozzles 15b may be divided into multiple groups. In this case, the number of assist nozzles 15b included in one group can be changed. The number of sub-valves 32a may be changed depending on the number of sub-nozzles 15a. The number of assist valves 32b may be changed depending on the number of assist nozzles 15b.

[0103] In the second embodiment, the control device 16 does not have to start air spray from the assist nozzle 15b at the same time as starting air spray from the stretch nozzle 51. The timing at which spray starts from the assist nozzle 15b may be simultaneous with the timing at which spray starts or stops from the other nozzles, or may be different from the timing at which spray starts or stops from the other nozzles.

[0104] In the second embodiment, the control device 16 does not have to stop air injection from the assist nozzle 15b at the same time as stopping air injection from the sub-nozzle 15a located at the most downstream side in the weft insertion direction X within the weaving width TL. The timing at which injection from the assist nozzle 15b stops may be simultaneous with the injection start or injection stop timing from the other nozzles, or may be different from the injection start or injection stop timing from the other nozzles. For example, the control device 16 may stop air injection from the assist nozzle 15b at the same time as stopping air injection from the stretch nozzle 51.

[0105] The control device 16 may be capable of executing both the assist control for accelerating the flight of the weft yarn Y and the assist control for suppressing the slack of the weft yarn Y in addition to the relay control in each weft insertion operation. When the control device 16 estimates a delay in the flight of the weft yarn Y, it performs the relay control, the assist control for accelerating the flight of the weft yarn Y, and the assist control for suppressing the slack of the weft yarn Y. When the control device 16 estimates that the flight of the weft yarn Y is not delayed or predicts that no delay will occur, it performs the relay control and the assist control for suppressing the slack of the weft yarn Y, and does not perform the assist control for accelerating the flight of the weft yarn Y. In this case, the assist nozzle 15b that injects air in the assist control for accelerating the flight of the weft yarn Y and the assist nozzle 15b that injects air in the assist control for suppressing the slack of the weft yarn Y may be the same as or different from each other. [Explanation of symbols]

[0106] Pi...predetermined position, Pw...final arrival position, T...warp thread, Ti...intermediate arrival time, Tw...final arrival time, X...weft insertion direction, Y...weft thread, 1...air jet loom, 10...weft insertion device, 14...reed, 14a...reed passage, 15a...sub-nozzle, 15b...assist nozzle, 16...control device, 17...storage drum, 18...weft locking pin, 19...balloon sensor (as weft detection unit), 22...main nozzle, 41...intermediate arrival time detection sensor (as weft detection unit), 45...state detection sensor (as weft detection unit), 50...tensioning device, 51...stretch nozzle, TL...weaving width.

Claims

1. a weft insertion device which repeatedly performs a weft insertion operation in which a weft wound on a storage drum is unwound by retracting a weft locking pin, and the unwound weft is made to fly through a reed passage of a reed by air jets from a main nozzle and a plurality of sub-nozzles, thereby inserting the weft into a warp shed; a control device for controlling air ejection from the main nozzle and the plurality of sub-nozzles, a direction in which the weft yarn flies when the weft yarn is inserted into the warp shed is defined as a weft insertion direction, and the plurality of sub-nozzles are aligned in the weft insertion direction, the control device is an air jet loom that performs relay control to sequentially inject air from the sub-nozzle located upstream in the weft insertion direction to the sub-nozzle located downstream in each weft insertion operation, a plurality of sub-nozzles, and an assist nozzle is provided within the weaving width, the assist nozzle injecting air into the weft yarn so as to apply a traction force in the weft insertion direction to the weft yarn, and the air injection is controlled by the control device; The control device is capable of executing, in addition to the relay control, an assist control for injecting air from the assist nozzle during each weft insertion operation.

2. a weft detection unit for detecting information regarding the flight of the weft before the weft reaches a final arrival position, 2. The air jet loom according to claim 1, wherein the control device performs a delay estimation to estimate a delay in the flight of the weft yarn based on a detection result from the weft detection unit, and performs the assist control when the delay in the flight of the weft yarn is estimated.

3. 3. The air jet loom according to claim 2, wherein the weft detection unit is a balloon sensor that detects the weft being unwound from the storage drum.

4. 3. The air jet loom according to claim 2, wherein the weft detection section is a state detection sensor that detects a state of the weft before it is inserted.

5. 3. The air jet loom according to claim 2, wherein the weft detection unit is an intermediate arrival time detection sensor that detects an intermediate arrival time when a tip end of the inserted weft reaches a predetermined position upstream of the final arrival position in the weft insertion direction.

6. The air jet loom according to any one of claims 2 to 5, wherein the assist nozzle is located upstream in the weft insertion direction within the weaving width.

7. The air jet loom according to claim 6, wherein the assist nozzle is positioned only on the upstream side in the weft insertion direction within the weaving width.

8. The assist nozzle is located upstream of the weft insertion direction within the weaving width, The air jet loom according to claim 1 , wherein the control device performs the assist control after the tip of the weft yarn reaches a final arrival position.

9. a stretch nozzle that is disposed downstream of the final arrival position in the weft insertion direction and that injects air onto the weft yarn, the air injection of the stretch nozzle being controlled by the control device; 9. The air jet loom according to claim 8, wherein the control device starts air jetting from the assist nozzle at the same time as starting air jetting from the stretch nozzle.

10. 10. The air jet loom according to claim 8 or claim 9, wherein the control device stops air jetting from the assist nozzle at the same time as stopping air jetting from the sub-nozzle located most downstream in the weft insertion direction within the weaving width.

Images