Weft insertion method and weft insertion device in air jet loom

Abstract

To provide a weft insertion method and a weft insertion device, capable of suppressing the disorder of a yarn posture of a weft yarn at the time of weft insertion which has an adverse effect on the weft insertion while preventing the weft yarn from being damaged by residual pressure in an air jet loom comprising the weft insertion device for supplying compressed air to respective main nozzles by bringing respective valve devices into an open state over an injection period from injection start timing in the weft insertion device in the air jet loom in which a first main nozzle for weft insertion is connected to a first valve device via first piping and a second main nozzle as an auxiliary main nozzle is connected to a second main valve via second piping shorter than the first piping.SOLUTION: In the air jet loom, an operation state of a second valve device is brought into a small flow rate state which is a state of supplying a flow rate smaller than a steady flow rate which is a flow rate in an injection steady state in an initial injection period in which injection start timing is set in advance as a starting point.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention includes a first main nozzle for weft insertion and a second main nozzle disposed upstream of the first main nozzle and functioning as an auxiliary main nozzle. The first main nozzle is connected to a first valve device via a first pipe, and the second main nozzle is connected to a second valve device via a second pipe shorter than the first pipe. The present invention relates to a weft insertion device in an air jet loom, and an air jet loom provided with a weft insertion device that supplies compressed air to each main nozzle by opening each valve device over an injection period from a preset injection start timing.

Background Art

[0002] As a weft insertion device in an air jet loom, for example, there is one disclosed in Patent Document 1. The weft insertion device includes, in addition to a main nozzle that mainly contributes to weft insertion, a tandem nozzle that is disposed upstream in the weft insertion direction from the main nozzle and functions as an auxiliary main nozzle that assists weft insertion by the main nozzle. That is, in the weft insertion device, the main nozzle and the tandem nozzle cooperate to perform one weft insertion.

[0003] In a general loom, the main nozzle is provided on a reed holder to which a reed is attached and that swings in the longitudinal direction of the loom during weaving. On the other hand, the auxiliary main nozzle is supported by a shaft erected on the loom frame via a bracket or the like and is fixedly provided on the loom.

[0004] In addition, the weft insertion device is provided corresponding to each of the main nozzle and the auxiliary main nozzle, and includes an electromagnetic valve for controlling the supply of compressed air to the main nozzle and the auxiliary main nozzle in the above-described weft insertion. In the weft insertion device, each electromagnetic valve is connected to the corresponding main nozzle or auxiliary main nozzle via a pipe. Then, by keeping each electromagnetic valve in an open state over the injection period from a preset injection start timing, compressed air is supplied to the main nozzle and the auxiliary main nozzle, and the above-described weft insertion is executed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, as also disclosed in Patent Document 1, in a general loom, the weft insertion device is configured such that the pipe from the electromagnetic valve to the auxiliary main nozzle is longer than the pipe to the main nozzle. According to this configuration, there is an advantage that the rise of the pressure of the compressed air jetted from the auxiliary main nozzle becomes gentler than that of the main nozzle, and as a result, the disturbance of the yarn posture of the weft yarn to be inserted is suppressed.

[0007] However, in such a configuration, on the side of the auxiliary main nozzle, the time required for the residual pressure in the pipe to escape becomes longer, resulting in a problem that the weft yarn is damaged. More specifically, even if the electromagnetic valve that is in the open state during the injection period is closed at the injection end timing, at that time, the compressed air (residual pressure) remains in the pipes leading to the main nozzle and the auxiliary main nozzle. Therefore, until the residual pressure escapes, an air flow corresponding to the pressure acts on the weft yarn connected to the main nozzle and the auxiliary main nozzle. Further, the time during which the air flow due to the residual pressure acts is a time corresponding to the length of the pipe. Therefore, in a configuration where the pipe leading to the auxiliary main nozzle is long as described above, on the side of the auxiliary main nozzle, the air flow due to the residual pressure acts on the weft yarn for a long time, and thus there may occur a problem that the weft yarn is damaged thereby.

[0008] On the other hand, among the looms known in the prior art, there is also a loom in which the weft insertion device is configured such that the pipe from the electromagnetic valve to the auxiliary main nozzle is shorter than the pipe on the main nozzle side. And in that configuration, the problem that the weft yarn is damaged by the air flow due to the residual pressure as described above hardly occurs. However, in that configuration, contrary to the case where the pipe on the auxiliary main nozzle side is long as described above, the rise of the pressure of the compressed air injected from the auxiliary main nozzle becomes steeper than that of the main nozzle. As a result, there may occur a problem that the yarn posture of the weft yarn being inserted is disturbed, which has an adverse effect on the weft insertion.

[0009] Therefore, an object of the present invention is to provide a weft insertion method and a weft insertion device that can suppress the disturbance of the yarn posture of the weft yarn during weft insertion, which has an adverse effect on weft insertion, in an air jet loom including a weft insertion device configured such that the pipe on the auxiliary main nozzle side is shorter than the pipe on the main nozzle side in order to prevent the weft yarn from being damaged by the residual pressure.

Means for Solving the Problems

[0010] The present invention relates to a weft insertion device in an air jet loom including a first main nozzle for weft insertion and a second main nozzle disposed upstream of the first main nozzle and functioning as an auxiliary main nozzle. The first main nozzle is connected to a first valve device via a first pipe, and the second main nozzle is connected to a second valve device via a second pipe shorter than the first pipe. The weft insertion device is based on an air jet loom equipped with a weft insertion device that supplies compressed air to each main nozzle by keeping each valve device open over an injection period from a preset injection start timing.

[0011] Furthermore, the weft insertion method according to the present invention is characterized in that, in an air jet loom equipped with the weft insertion device based on the above premise, the operating state of the second valve device is set to a low flow state in which a flow rate less than a steady flow rate, which is the flow rate in a steady state of injection, is supplied during a preset initial injection period starting from the injection start timing.

[0012] Here, the "operating state" of the second valve device refers to a mechanically defined state (open state) for the valve device. That is, although its operating state is represented in relation to the flow rate as in the above-mentioned "state of supplying the flow rate", it is not a state based on the relationship with the actual flow rate of the compressed air actually supplied from the valve device (actual flow rate), but a mechanical open state as a result of the operation of the valve device and a state that can supply a preset flow rate (assumed flow rate).

[0013] More specifically, the valve device operates at the injection start timing and assumes a set mechanical open state. However, the actual flow rate does not immediately reach the assumed flow rate corresponding to the open state of the valve device, but rather reaches the assumed flow rate through a process of gradually increasing. Thus, even when the valve device is in the mechanical open state set according to the assumed flow rate, the actual flow rate includes a state in which a flow rate less than the assumed flow rate is supplied. However, the "operating state" of the valve device referred to in the present invention does not take into account such a changing actual flow rate, but rather refers to the state of the valve device determined as a mechanical open state defined in relation to the assumed flow rate.

[0014] Furthermore, the "steady flow rate" is, as described above, the flow rate in the steady state of injection, and more specifically, the flow rate supplied from the valve device corresponding to each main nozzle when the injection of each main nozzle is in the steady state. And the steady state of the injection refers to a state in which the actual flow rate supplied from the valve device to the main nozzle during the weft insertion period is the assumed flow rate.

[0015] Furthermore, regarding the "initial injection period (preset)" mentioned above, the initial injection period is a period starting from the injection start timing set for the second valve device as described above, and the end point of this period is determined in consideration of various conditions related to weft insertion. The various conditions include the relationship between the injection start timing of the second valve device and the injection start timing of the first valve device, the set pressure of the compressed air supplied to the second valve device, the set rotational speed of the loom (main shaft), and the length of the first pipe that significantly affects the rising characteristics of the pressure of the compressed air injected from the first main nozzle.

[0016] Further, in the weft insertion device according to the present invention, the second valve device is configured to be able to change its operating state between a state of supplying a steady flow rate, which is the flow rate in the steady state of injection, and a low flow rate state of supplying a flow rate less than the steady state. And the weft insertion device includes a memory that stores an initial injection period preset starting from the injection start timing, and a control device that switches the operating state of the second valve device and sets the operating state of the second valve device in the initial injection period to the low flow rate state. This is the feature.

[0017] Also, in the weft insertion method and the weft insertion device according to the present invention, the weft insertion device is provided with a third main nozzle arranged upstream of the second main nozzle and connected to a third valve device. The third valve device may be set to supply a steady flow rate over the injection period. Further, in the weft insertion method and the weft insertion device according to the present invention, the weft insertion device may be configured such that the second valve device is integrally provided with respect to the second main nozzle.

Advantages of the Invention

[0018] According to the present invention, in the weft insertion device, the second main nozzle as an auxiliary main nozzle arranged upstream of the first main nozzle (main nozzle) is connected to a corresponding second valve device by a shorter pipe (second pipe) than the pipe (first pipe) on the first main nozzle side. Therefore, according to this configuration, it is difficult to cause a problem that the weft yarn is damaged due to the residual pressure on the second main nozzle (second pipe) side as described above.

[0019] Furthermore, in the present invention, in the initial injection period starting from the injection start timing which is the start point of the injection period, the operating state of the second valve device is set to a low flow rate state in which a flow rate less than the steady flow rate is supplied. Thereby, in that initial injection period, compared with a configuration in which the operating state of the second valve device is configured to supply the steady flow rate throughout the injection period like a conventional weft insertion device, the supply flow rate of the compressed air supplied to the second main nozzle becomes less than the steady flow rate. Therefore, according to such a present invention, since the rise of the pressure of the compressed air injected from the second main nozzle becomes gentle in the initial injection period, the disturbance of the yarn posture of the weft yarn to be inserted is suppressed, and the problem of adversely affecting the weft insertion can be prevented as much as possible.

[0020] Also, in the weft insertion device according to the present invention, by making the third valve device to which the auxiliary main nozzle (third main nozzle) arranged upstream of the second main nozzle is connected supply the steady flow rate throughout the injection period, the configuration of the weft insertion device as a whole can be simplified.

[0021] More specifically, when the weft insertion device includes two or more auxiliary main nozzles upstream of the first main nozzle, instead of making all of them the second main nozzle (the auxiliary main nozzle connected to the second valve device) described above, after making the auxiliary main nozzle located on the downstream side (a number less than the total number) the second main nozzle described above, even if the remaining upstream auxiliary main nozzles are made the third main nozzle connected to the third valve device as described above, the effects intended by the present invention can be obtained.

[0022] And since the third valve device is configured only to supply the steady flow rate as described above and may be a simple electromagnetic valve that only switches between an open state and a closed state, it has a simpler configuration compared to the second valve device configured to be able to change the supply flow rate. Therefore, when two or more auxiliary main nozzles are provided, the configuration of the weft insertion device can be further simplified compared to the case where all the auxiliary main nozzles are the second main nozzles described above.

[0023] Furthermore, in the weft insertion device according to the present invention, by configuring the weft insertion device such that the second valve device is provided integrally with the second main nozzle, problems such as the weft yarn being damaged due to the residual pressure as described above are less likely to occur, and moreover, in terms of the effect of being able to suppress the disturbance of the yarn posture described above, the present invention will contribute more effectively.

[0024] More specifically, by configuring the weft insertion device such that the second valve device connected to the second main nozzle is provided integrally with the second main nozzle, on the second main nozzle side, the second pipe connecting the second main nozzle and the second valve device becomes extremely short compared to the case where the second valve device is provided at a position separated from the second main nozzle. And in that case, problems such as the weft yarn being damaged due to the residual pressure in the second pipe are even less likely to occur.

[0025] However, since the second pipe becomes shorter in this way, the rise in the pressure of the compressed air from the start of injection on the second main nozzle side becomes more rapid. Therefore, by applying the present invention that can moderate the rise in the pressure of the compressed air on the second main nozzle side for the weft insertion device configured in this way, the present invention functions (contributes) more effectively in terms of the effect of being able to suppress the disturbance of the yarn posture described above.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

BEST MODE FOR CARRYING OUT THE INVENTION

[0027] Hereinafter, based on Figs. 1 to 6, an embodiment (example) of the weft insertion device of an air jet loom to which the present invention is applied will be described.

[0028] Fig. 1 shows the weft insertion device 3 in the air jet loom 1 on which the present invention is premised, and shows the peripheral portion of the main nozzle in the weft insertion device 3. As shown in the figure, the weft insertion device 3 mainly includes, in addition to the first main nozzle N1 as the main nozzle that contributes to the weft insertion of the weft yarn, an auxiliary main nozzle N2 disposed upstream of the first main nozzle N1 in the weft insertion direction for the purpose of assisting the weft insertion by the first main nozzle N1.

[0029] Incidentally, in the illustrated example, the weft insertion device 3 is a multi-color weft insertion device 3 having a plurality of first main nozzles N1. Further, in the weft insertion device 3, for each first main nozzle N1, a pair of two auxiliary main nozzles N2, N2 is provided correspondingly. Regarding the two auxiliary main nozzles N2, N2 in each pair, hereinafter, the one arranged on the upstream side in the weft insertion direction is referred to as the upstream auxiliary main nozzle N2, and the one provided on the downstream side is referred to as the downstream auxiliary main nozzle N2.

[0030] Incidentally, in the weft insertion device 3, each first main nozzle N1 is provided on a reed holder RH to which a reed R is attached and which swings in the longitudinal direction of the loom during weaving. On the other hand, in the illustrated example, the two auxiliary main nozzles N2, N2 in each pair are connected by a stay 5 and supported by a support stand 2 erected on the frame F of the loom via the stay 5. That is, each auxiliary main nozzle N2 is fixedly provided on the loom. Incidentally, the upstream and downstream auxiliary main nozzles N2, N2 in each pair are arranged side by side in the axial direction and are arranged such that their axes coincide when viewed in the axial direction. Further, each auxiliary main nozzle N2 is provided in such a manner that its axis is directed to the rear end of the corresponding first main nozzle N1.

[0031] The weft insertion device 3 further includes a valve device including an electromagnetic valve (electromagnetic on-off valve) provided corresponding to each main nozzle in order to control the supply of compressed air to each of the first main nozzle N1 and the auxiliary main nozzle N2.

[0032] More specifically, the valve device V1 for the first main nozzle N1 is the first valve device according to the present invention, and a plurality of valve devices V1 are provided corresponding to each of the plurality of first main nozzles N1. Each of the first valve devices V1 is provided on a lead holder RH by which the first main nozzle N1 is swing-driven, and is fixedly provided in a manner attached to the frame F of the loom. And each of the first valve devices V1 is connected to the corresponding first main nozzle N1 via a pipe H1 as a first pipe.

[0033] Also, a plurality of valve devices V2 for the auxiliary main nozzles N2 are provided corresponding to each of the auxiliary main nozzles N2. Although details will be described later, in this embodiment, the valve device V2 is integrally provided for each corresponding auxiliary main nozzle N2. Therefore, the pipe connecting the valve device V2 integrally provided for the auxiliary main nozzle N2 and the auxiliary main nozzle N2 in this way is shorter than the pipe H1 connecting the first main nozzle N1 on the lead holder RH and the first valve device V1 on the frame F described above.

[0034] And in the weft inserting device 3 configured as described above, in each weaving cycle, each of the valve devices V1 and V2 provided for the selected first main nozzle N1 and the corresponding auxiliary main nozzle N2 is opened at a preset injection start timing, so that compressed air is supplied to the first main nozzle N1 and each auxiliary main nozzle N2, and compressed air is injected from the first main nozzle N1 and each auxiliary main nozzle N2 to insert the weft. Furthermore, in this embodiment, for the injection start timing for opening each of the valve devices V1 and V2, first, the injection of compressed air from the first main nozzle N1 is started, then the injection of compressed air is started in the order of the downstream auxiliary main nozzle N2 and finally the upstream auxiliary main nozzle N2, and their respective injection start timings are set.

[0035] In the air-jet loom 1 equipped with the weft insertion device 3 configured as described above, in the present invention, the weft insertion device 3 is such that a valve device V2 provided for an auxiliary main nozzle N2 corresponding to each first main nozzle N1 can be in a state of supplying a flow rate (steady flow rate) in the steady state of the injection of the auxiliary main nozzle N2, and also in a state of supplying a flow rate less than the steady flow rate (low flow rate state). Then, the present invention is characterized in that the operating state of the second valve device is in the low flow rate state during an initial injection period preset starting from the injection start timing.

[0036] Furthermore, in this embodiment, the valve device V2 provided for the auxiliary main nozzle N2 on the downstream side of each set is taken as an example of the second valve device 21 described above. Therefore, the auxiliary main nozzle N2 on the downstream side corresponds to the second main nozzle 20 in the present invention. On the other hand, for the valve device V2 provided for the auxiliary main nozzle N2 on the upstream side in each set, the valve device V2 is a valve device (third valve device) 31 configured such that the possible operating state is only the state of supplying the steady flow rate. And the auxiliary main nozzle N2 on the upstream side is, in terms of configuration, the same auxiliary main nozzle, but it is the third main nozzle 30 instead of the second main nozzle 20.

[0037] Regarding the common configuration of each of the two auxiliary main nozzles N2, N2 (the second main nozzle 20 and the third main nozzle 30) in each set, since the configuration itself is the same as the well-known one, a detailed description is omitted, but the second main nozzle 20 and the third main nozzle 30 are mainly composed of nozzle body parts 25, 35 to which compressed air is supplied in a form corresponding to each main nozzle.

[0038] Further, the second main nozzle 20 and the third main nozzle 30 include thread guides 27 and 37 respectively attached to the corresponding nozzle body parts 25 and 35, and pipe parts 26 and 36 integrally provided with the nozzle body parts 25 and 35 in such a manner as to be inserted into the nozzle body parts 25 and 35 at one end. And, in the nozzle body parts 25 and 35 corresponding to the respective main nozzles, a supply flow path for compressed air is formed in such a way as to communicate with through holes 25a and 35a in which a part of the thread guides 27 and 37 is installed. Note that, for the nozzle body parts 25 and 35, the surface facing upward on the loom is referred to as the upper surface, the surface facing downward is referred to as the lower surface, the surface facing the downstream side in the weft insertion direction is referred to as the front surface, and the surface facing the upstream side is referred to as the rear surface. Further, the two surfaces excluding the upper surface, the lower surface, the front surface, and the rear surface and parallel to the through direction of the through holes 25a and 35a are referred to as the side surfaces.

[0039] Regarding such a second main nozzle 20 and a third main nozzle 30, first, regarding a third valve device 31 provided for the third main nozzle 30, the third valve device 31 is integrally provided with the nozzle body part 35 of the corresponding third main nozzle 30. Regarding the nozzle body part 35 where the third valve device 31 is provided, a supply flow path for compressed air is formed in the nozzle body part 35 as described above.

[0040] The supply flow path is configured to have a main flow path 35b communicating with the through hole 35a, an annular (doughnut-shaped in cross-section) annular flow path 35c formed around the main flow path 35b, and an introduction flow path 35d into which compressed air supplied from a supply source (not shown) of compressed air flows (is introduced). Further, the supply flow path is configured to have a communication flow path 35f that opens to the side surface of the nozzle body part 35 and is formed so that the main flow path 35b and the annular flow path 35c communicate with each other.

[0041] Regarding the supply channel, more specifically, the communication channel 35f is a channel formed to open to one of the two side surfaces of the nozzle main body 35, and is a channel formed by drilling in a direction (width direction) orthogonal to the one side surface. Further, the inner diameter of the communication channel 35f is such that it substantially coincides with the outer diameter of the annular channel 35c that communicates with the communication channel 35f as described above. Note that the annular channel 35c is a channel formed around (surrounding) the main channel 35b as described above. Therefore, the inner diameter of the communication channel 35f is naturally larger than the inner diameter of the main channel 35b.

[0042] Also, the main channel 35b extends in the width direction, communicates with the communication channel 35f at one end side, communicates with the through hole 35a as described above at the other end, and is formed so as to communicate the through hole 35a and the communication channel 35f. Thereby, in the supply channel, the main channel 35b communicates the communication channel 35f and the through hole 35a. Note that the through hole 35a with which the main channel 35b communicates is a portion (channel) where the thread guide 37 in the third main nozzle 30 is installed and the pipe portion 36 is continuous. Therefore, the inner diameter (flow path diameter) of the main channel 35b is sized to enable the supply of compressed air at a predetermined assumed flow rate that realizes a desired weft insertion (the steady flow rate). Incidentally, in the illustrated example, the portion on one end side of the main channel 35b is formed to have a slightly larger diameter than the other portions.

[0043] In addition, the annular flow path 35c is formed as a flow path that forms an annulus around the main flow path 35b as described above. And the annular flow path 35c is formed so as to communicate with the communication flow path 35f at one end thereof as described above. Further, the annular flow path 35c is formed such that the other end thereof is located near the middle portion of the main flow path 35b with respect to the width direction. Incidentally, the annular flow path 35c is formed so as to surround the main flow path 35b as described above, and the inner diameter thereof is naturally larger than the inner diameter of the main flow path 35b. Therefore, in the nozzle body portion 35, there is an annular end face (annular end face) 35g that is exposed to the communication flow path 35f between the communication end of the annular flow path 35c with respect to the communication flow path 35f and the communication end of the main flow path 35b with respect to the communication flow path 35f.

[0044] In addition, the introduction flow path 35d is formed to open to the front surface of the nozzle body portion 35 and communicate with a portion on the other end side of the annular flow path 35c. And a pipe joint 35e to which a supply pipe for supplying compressed air is connected is attached to the introduction flow path 35d.

[0045] In addition, the third valve device 31 provided for the nozzle body portion 35 configured as described above is a valve device configured such that the operating state it can achieve is only the state of supplying the steady flow rate as described above, and is composed of a general electromagnetic valve that is structurally the same as the first valve device V1. However, in the third valve device 31 of the present embodiment, the portion excluding the disk-shaped valve body 31a and the valve body driving portion 31b that is the portion for driving the valve body 31a is configured by a part of the nozzle body portion 35. In other words, a part of the nozzle body portion 35 also serves as a part of the third valve device 31. Then, in the third valve device 31 configured as such, the valve body driving portion 31b is attached in a manner fixed to the one side surface of the nozzle body portion 35.

[0046] Note that the attachment of the valve body drive unit 31b to the nozzle body unit 35 is performed via an attachment member 38. Specifically, the attachment member 38 is attached to the one side surface of the nozzle body unit 35 in such a manner as to cover the portion where the communication flow path 35f opens. Further, in the plate-like portion of the attachment member 38 that covers the communication flow path 35f (opening portion), a through hole having an inner diameter smaller than the inner diameter of the communication flow path 35f is formed at a position where the center coincides with the communication flow path 35f (main flow path 35b) when viewed in the width direction.

[0047] Further, the valve body drive unit 31b is provided with a plunger 31b1 that is driven to be displaced in the axial direction by a solenoid (not shown) built in the main body 31b2 so as to protrude from the main body 31b2. The valve body 31a is attached to the tip of the plunger 31b1. Then, the valve body drive unit 31b is attached to the attachment member 38 attached to the nozzle body unit 35 as described above by inserting the plunger 31b1 into the through hole of the attachment member 38.

[0048] Therefore, in the state (attachment state) where the valve body drive unit 31b is attached to the attachment member 38 in this manner, the valve body 31a is located within the communication flow path 35f in the nozzle body unit 35. And in the attachment state, one end surface of the valve body 31a faces the annular end surface 35g in the nozzle body unit 35, and the other end surface faces the attachment member 38. Incidentally, the inner diameter of the through hole in the attachment member 38 is, of course, larger than the outer diameter of the (inserted) plunger 31b1, but smaller than the outer diameter of the valve body 31a.

[0049] Note that the outer diameter of the valve body 31a is substantially the same (slightly smaller) as the inner diameter of the communication flow path 35f. Further, the thickness dimension of the valve body 31a is smaller than the size of the communication flow path 35f in the width direction. Therefore, in the mounted state, the valve body 31a is slidable in the width direction with its outer peripheral surface guided by the inner peripheral surface of the communication flow path 35f. And the sliding of the valve body 31a is regulated by the annular end surface 35g in the nozzle main body portion 35 and the mounting member 38. Moreover, the thickness dimension of the valve body 31a is such that a gap allowing the compressed air of the steady flow rate to flow between the valve body 31a and the annular end surface 35g is formed in a state where the valve body 31a slides toward the mounting member 38 side and abuts against the mounting member 38.

[0050] And in the third valve device 31 configured such that the valve body driving portion 31b is attached to the nozzle main body portion 35 as described above, when the plunger 31b1 is driven and the valve body 31a is brought into contact with the annular end surface 35g, the annular flow path 35c communicating with the introduction flow path 35d and the main flow path 35b communicating with the through hole 35a in which the thread guide 37 is installed are isolated (non - communicating state) by the valve body 31a. Thereby, even when compressed air is being supplied to the annular flow path 35c via the introduction flow path 35d, the compressed air does not flow to the main flow path 35b side, and the injection of compressed air from the third main nozzle 30 is not performed. Therefore, in this configuration, the annular end surface 35g in the nozzle main body portion 35 functions as a valve seat in the third valve device 31.

[0051] Further, when the plunger 31b1 is driven and the valve body 31a is brought into contact with the mounting member 38, a gap as described above is formed between the valve body 31a and the annular end face 35g, and the annular flow path 35c and the main flow path 35b are in a communicating state. As a result, the compressed air supplied to the annular flow path 35c via the introduction flow path 35d flows toward the main flow path 35b side, and the compressed air is ejected from the third main nozzle 30. In the steady state of the ejection, the compressed air of the steady flow rate is ejected from the third main nozzle 30. Note that the state of the third valve device 31 in which the valve body 31a is in contact with the mounting member 38 and the main flow path 35b is in communication with the supply side with a gap of such a size that the compressed air of the steady flow rate can flow is the state in which the above-described “(attainable) operating state is the state of supplying the steady flow rate”.

[0052] Next, regarding the second valve device 21 provided for the second main nozzle 20, the second valve device 21 is also integrally provided for the nozzle body portion 25 of the corresponding second main nozzle 20. The supply flow path in the nozzle body portion 25 of the second main nozzle 20 also includes a communication flow path 25f, a main flow path 25b, an annular flow path 25c, and an introduction flow path 25d formed in the same form as the communication flow path 35f, the main flow path 35b, the annular flow path 35c, and the introduction flow path 35d of the nozzle body portion 35 of the third main nozzle 30. An annular end face 25g exposed to the communication flow path 25f exists in the supply flow path. Further, also in the second main nozzle 20, a pipe joint 25e is attached to the introduction flow path 25d in the nozzle body portion 25.

[0053] Furthermore, the second valve device 21 is configured to be able to change its operating state between the state of supplying the aforementioned steady flow rate and the low flow rate state as described above. In this embodiment, it is configured by combining two electromagnetic valves with different achievable operating states. And those two electromagnetic valves are an electromagnetic valve (steady flow rate valve) 22 configured such that the achievable operating state is only the state of supplying the steady flow rate, and an electromagnetic valve (low flow rate valve) 23 configured such that the achievable operating state is only the low flow rate state.

[0054] Note that the steady flow rate valve 22 is structurally the same as the third valve device 31, and includes a valve body driving part 22b including a plunger 22b1 that is displacement-driven by a solenoid built into the main body 22b2 and the main body 22b2, a valve body 22a attached to the tip of the plunger 22b1 in the valve body driving part 22b, and a part of the nozzle main body part 25 that is a part of the steady flow rate valve 22 excluding the valve body driving part 22b. And the steady flow rate valve 22 is also configured such that the valve body driving part 22b (main body 22b2) is attached to the nozzle main body part 25 via an attachment member 28, similar to the third valve device 31. And also in the steady flow rate valve 22, the valve body 22a is slidable in the width direction within the communication flow path 25f.

[0055] Also, the low flow rate valve 23 is configured to include a valve body driving part 23b including a plunger 23b1 that is axially displacement-driven by a solenoid built into the main body 23b2 and the main body 23b2, and a valve body 23a attached to the tip of the plunger 23b1 in the valve body driving part 23b, similar to the steady flow rate valve 22.

[0056] However, the constant flow valve 22 is configured such that the part where the valve body 22a is accommodated and the valve seat (annular end face) 25g is formed is a part of the nozzle main body 25. The low flow valve 23 includes a valve housing part 23c separate from the nozzle main body 25. A valve seat 23c1 is formed in the valve housing part 23c, and the valve body 23a is configured to be accommodated therein. That is, the low flow valve 23 is configured by combining the valve body drive part 23b and the valve housing part 23c.

[0057] Regarding the valve housing part 23c, more specifically, the valve housing part 23c is a block-shaped member having a thick shape. In the valve housing part 23c, an accommodation space 23c2 for accommodating the valve body 23a, an inflow passage 23c3 that communicates with the accommodation space 23c2 and to which compressed air from a supply source is supplied, and an outflow passage 23c4 that communicates with the accommodation space 23c2 and discharges the compressed air that has flowed into the accommodation space 23c2 from the inflow passage 23c3 are formed.

[0058] Among them, the accommodation space 23c2 is formed as a bottomed hole that opens only at one of the both end faces in the thickness direction of the valve housing part 23c, and is formed by drilling in the thickness direction. The accommodation space 23c2 is circular when viewed in the thickness direction, and its inner diameter is formed to be slightly larger (substantially the same) than the outer diameter of the valve body 23a. Further, the bottom surface of the accommodation space 23c2 is formed to be near the approximate middle part of the valve housing part 23c in the thickness direction. That is, regarding the thickness direction, the size (depth dimension) of the accommodation space 23c2 is about half of the valve housing part 23c. However, the depth dimension of the accommodation space 23c2 is naturally larger than the thickness dimension of the accommodated valve body 23a.

[0059] In addition, the outflow passage 23c4 is formed to open at the other end face of both end faces of the valve housing portion 23c and communicate with the accommodation space 23c2. Further, the outflow passage 23c4 is formed at a position where the center of the passage coincides with the center of the accommodation space 23c2 when viewed in the thickness direction. However, the inner diameter (flow path diameter) of the outflow passage 23c4 is naturally smaller than the inner diameter of the accommodation space 23c2 and is sized to enable the supply of compressed air with a flow rate (low flow rate) less than the steady flow rate. And in the valve housing portion 23c, the portion of the bottom surface of the accommodation space 23c2 excluding the portion where the outflow passage 23c4 opens serves as the valve seat 23c1.

[0060] In addition, the inflow passage 23c3 is formed to open at the other end face of the valve housing portion 23c at a position radially spaced from the outflow passage 23c4 in the accommodation space 23c2 and is formed to be parallel to the inflow passage 23c3. Note that the inflow passage 23c3 is formed such that the center of the passage is located near the periphery of the accommodation space 23c2 when viewed in the thickness direction. Therefore, on the accommodation space 23c2 side, about half of the inflow passage 23c3 opens to the bottom surface.

[0061] In the low-flow valve 23, the valve body driving part 23b is attached to the valve housing part 23c configured as described above in such a manner that the valve body 23a is positioned within the accommodation space 23c2 in the valve housing part 23c. As described above, the depth dimension of the accommodation space 23c2 in the valve housing part 23c is larger than the thickness dimension of the valve body 23a. Therefore, in the state where the valve body driving part 23b is attached to the valve housing part 23c, the valve body 23a is slidable within the accommodation space 23c2. And the slide is regulated by the valve seat 23c1 facing the valve body 23a and the main body 23b2 of the valve body driving part 23b. Moreover, the thickness dimension of the valve body 23a is such that a gap allowing the compressed air of the low flow rate to flow between the valve body 23a and the valve seat 23c1 is formed in the state where the valve body 23a slides to the main body 23b2 side and abuts against the main body 23b2.

[0062] The low-flow valve 23 configured in such a manner that the valve body driving part 23b is attached to the valve housing part 23c is attached to the nozzle main body part 25 in a state where the other end face in the valve housing part 23c abuts against the upper face in the nozzle main body part 25 in a fixed manner. Regarding the attachment, in the width direction, the position of the inflow passage 23c3 in the valve housing part 23c is aligned with the position of the other end side part of the annular passage 25c in the nozzle main body part 25 (the position where the introduction passage 25d communicates), and the outflow passage 23c4 is arranged to be located on the other end face side of the nozzle main body part 25 with respect to the inflow passage 23c3 (the side opposite to the side where the constant-flow valve 22 is attached), and the attachment is performed in such an arrangement.

[0063] On top of that, in the nozzle main body 25 to which the low-flow valve 23 is attached, a lead-out passage 25h that connects the annular passage 25c and the inflow passage 23c3 in the valve housing portion 23c, and a sub-passage 25k that connects the outflow passage 23c4 in the valve housing portion 23c and the main passage 25b are formed. The lead-out passage 25h is a passage having substantially the same inner diameter as the inflow passage 23c3, and is formed in such a manner that the direction of the passage coincides with the direction (vertical direction) orthogonal to the upper surface of the nozzle main body 25. Therefore, the communication position of the lead-out passage 25h with respect to the annular passage 25c is the position of the other end side portion of the annular passage 25c in the width direction, and is different from the position where the introduction passage 25d communicates in the circumferential direction of the annular passage 25c. The sub-passage 25k is a passage having substantially the same inner diameter as the outflow passage 23c4, and is formed in such a manner that the direction of the passage coincides with the vertical direction, similar to the lead-out passage 25h.

[0064] And in a state where the second valve device 21 is integrally provided with the nozzle main body 25 configured as described above, the low-flow valve 23 is in a state where the outflow passage 23c4 communicates with the main passage 25b through the sub-passage 25k in the nozzle main body 25 as described above, and communicates with the through-hole 25a through the main passage 25b. Also, the constant-flow valve 22 is configured such that the portion excluding the valve body driving portion 22b is formed of a part of the nozzle main body 25 as described above. Therefore, the portion of the main passage 25b in the nozzle main body 25 on the side of the communication passage 25f becomes a passage (valve-side passage) that forms a part of the second valve device 21. In other words, the main passage 25b is composed of the valve-side passage in the second valve device 21 and the nozzle-side passage (nozzle-side passage) H2 that connects the valve-side passage to the through-hole 25a.

[0065] And the sub-channel 25k communicates with the nozzle-side channel H2 thereof. From these facts, it can be said that the second valve device 21 is connected to the through-hole 25a in which the thread guide 27 in the second main nozzle 20 is installed, in the nozzle-side channel H2 in the main channel 25b. Therefore, the nozzle-side channel H2 corresponds to the second pipe in the present invention. And since the second pipe H2 is a channel formed inside the nozzle body part 25 where the second valve device 21 is integrally provided, it is clearly shorter than the pipe H1 connecting the first main nozzle N1 in the shape of the lead holder RH and the first valve device V1 on the frame F as described above.

[0066] And in the second valve device 21 configured as described above, when the valve body 23a in the low-flow valve 23 is in contact with the valve seat 23c1 in the valve housing part 23c and the valve body 22a in the constant-flow valve 22 is in contact with the attachment member 28, similar to the third valve device 31 described above, the compressed air supplied from the introduction channel 25d to the annular channel 25c flows into the main channel 25b through the gap between the valve body 22a and the valve seat (annular end face) 25g. And the operating state of the second valve device 21 is a state in which the compressed air of the constant flow rate is supplied.

[0067] On the one hand, when the valve element 22a in the constant flow valve 22 is in contact with the valve seat 25g and the valve element 23a in the low flow valve 23 is in contact with the main body 23b2, as described above, the compressed air supplied to the annular flow path 25c does not flow into the main flow path 25b on the constant flow valve 22 side, but flows from the annular flow path 25c through the lead-out flow path 25h into the inflow flow path 23c3 of the low flow valve 23. Then, on the low flow valve 23 side, the compressed air flowing into the inflow flow path 23c3 flows into the outflow flow path 23c4 through the gap between the valve element 23a and the valve seat 23c1. Then, the compressed air flowing through the outflow flow path 23c4 flows into the main flow path 25b via the sub-flow path 25k. Thus, in the operating state of the second valve device 21, the supplied compressed air flows into the main flow path 25b through the low flow valve 23 instead of the constant flow valve 22 side. And the operating state of the second valve device 21 is the state of supplying the low flow rate, that is, the low flow rate state.

[0068] And in any operating state, as the compressed air flows into the main flow path 25b as described above, the compressed air is injected from the second main nozzle 20 according to the flow rate. Incidentally, even when the valve element 22a in the constant flow valve 22 is in contact with the mounting member 28 and the valve element 23a in the low flow valve 23 is in contact with the main body 23b2, due to the relationship between the size of the gap between the valve element and the valve seat in each of the constant flow valve 22 and the low flow valve 23 and the diameter of the flow path following the gap, the compressed air is more likely to flow into the constant flow valve 22 side than the low flow valve 23 side. Therefore, the compressed air mainly flows into the main flow path 25b on the constant flow valve 22 side. Accordingly, the operating state is also the state of supplying the compressed air at the constant flow rate.

[0069] Further, as shown in FIG. 5, the weft insertion device 3 configured as described above includes a weft insertion control device 40 as a control device for controlling the operating states of the valve devices V1, 21, 31 in each main nozzle N1, 20, 30. The weft insertion control device 40 includes a memory 41 in which weft insertion conditions including the injection period of compressed air by each main nozzle N1, 20, 30 are stored. Note that the weft insertion device 3 of the present embodiment includes a plurality of first main nozzles N1 and two auxiliary main nozzles N2, N2 (second main nozzle 20, third main nozzle 30) provided for each first main nozzle N1. Further, the weft insertion conditions stored in the memory 41 also include a weft insertion order for selecting which set of main nozzles to perform injection (weft insertion) in each weaving cycle.

[0070] Regarding the injection period included in the weft insertion conditions, it is assumed that the injection start timing and the injection end timing corresponding to the injection period are stored in the memory 41. However, it is assumed that the injection start timing and the injection end timing are set by the rotation angle (crank angle) θ of the main shaft MS of the loom. Further, the weft insertion conditions include an initial injection period starting from the injection start timing set for the second valve device 21, and the initial injection period is set in consideration of various conditions related to weft insertion. That is, the initial injection period is stored in the memory 41 as one of the weft insertion conditions.

[0071] The air jet loom 1 is also provided with an input setter 42 for inputting and setting the above-described weft insertion conditions and the like. Further, the input setter 42 is also connected to the memory 41 in the weft insertion control device 40. The weft insertion conditions described above are input and set by the input setter 42, and the set weft insertion conditions are stored in the memory 41. Further, the air jet loom 1 is provided with an encoder EN that detects the rotation angle of the main shaft MS and outputs it as a crank angle signal θ. The encoder EN is also connected to the weft insertion control device 40 and outputs a crank angle signal θ corresponding to the detected rotation angle of the main shaft MS to the weft insertion control device 40.

[0072] And, for the set of main nozzles selected in each weaving cycle, the weft insertion control device 40 is configured to control the operating states of the first valve device V1, the second valve device 21, and the third valve device 31 based on the weft insertion conditions stored in its memory 41 and the crank angle signal θ from the encoder EN.

[0073] Also, regarding the injection start timing set for each of the first valve device V1, the second valve device 21, and the third valve device 31, in this embodiment, first, the injection start timing (the first injection start timing) set for the first valve device V1 is assumed to be set at a crank angle of 70°. Then, since the second main nozzle 20 (the downstream auxiliary main nozzle N2 mentioned above) starts injection after the injection start of the first main nozzle N1 as described above, the injection start timing (the second injection start timing) set for the second valve device 21 is assumed to be set at a crank angle of 80°, which is a crank angle later than the crank angle of 70° that is the first injection start timing. Further, since the third main nozzle 30 (the upstream auxiliary main nozzle N2 mentioned above) starts injection last, the injection start timing (the third injection start timing) set for the third valve device 31 is assumed to be set at a crank angle of 90°, which is a crank angle later than the crank angle of 80° that is the second injection start timing.

[0074] In this embodiment, it is assumed that the timing for ending the injection of each of the main nozzles N1, 20, and 30 is the same. Therefore, the injection end timings set for the first valve device V1, the second valve device 21, and the third valve device 31 are all at the same crank angle, and are assumed to be set at a crank angle of 180°.

[0075] Also, as described above, the operating state of the second valve device 21 is set to the low flow rate state during an initial injection period that is predetermined starting from the second injection start timing. That is, during the initial injection period from the second injection start timing, the second valve device 21 is in an operating state where only the low flow rate valve 23 that forms the low flow rate state is open, and at the end of the initial injection period, it is switched to an operating state where the normal flow rate valve 22 that supplies the compressed air at the normal flow rate is open. Furthermore, in this embodiment, the initial injection period is set so that, considering various conditions related to weft insertion, the timing at which the flow rate of the compressed air injected from the second main nozzle 20 reaches the normal flow rate is substantially the same as the timing at which the flow rate of the compressed air injected from the first main nozzle N1 reaches the normal flow rate.

[0076] Specifically, in the air jet loom 1 of this embodiment, in relation to the rotational speed of the loom set for weaving and the pressure of the compressed air supplied to each main nozzle, it is assumed that the timing at which the flow rate of the compressed air injected from the first main nozzle N1 reaches the normal flow rate is at a crank angle of 100°. Also, as described above, the timing at which the second main nozzle 20 starts injection is 10° of crank angle delay with respect to the timing at which the first main nozzle N1 starts injection.

[0077] Also, regarding the rise of the flow rate of the compressed air jetted from the second main nozzle 20, the degree of the rise of the flow rate of the compressed air (the increase amount per unit time of the flow rate) from the start of injection in the low flow rate state in the second valve device 21, and the degree of the rise of the flow rate of the compressed air after switching from the low flow rate state to the state of supplying the steady flow rate shall be determined in advance by tests or the like based on the rotational speed of the loom during weaving and the pressure of the compressed air supplied to each main nozzle. Note that the degree of the rise of the flow rate in both states is naturally gentler for the rise from the start of injection in the low flow rate state. Therefore, the longer the injection period in the low flow rate state, the later the timing at which the flow rate of the compressed air jetted from the second main nozzle 20 reaches the steady flow rate.

[0078] Then, based on these, at what timing after the second injection start timing (crank angle 80°) should the switching be made from the low flow rate state to the state of supplying the steady flow rate so that the flow rate of the compressed air jetted from the second main nozzle 20 reaches the steady flow rate at the desired timing (in this embodiment, crank angle 100°) is determined. And the period from the second injection start timing to the obtained switching timing is the initial injection period. Note that in this embodiment, the switching timing obtained in this way is the crank angle 90°, and therefore, it is assumed that the initial injection period is set to a period of 10° in terms of the crank angle.

[0079] In the weft insertion device 3 configured as described above, when the crank angle θ reaches 70° (the first injection start timing) in each weaving cycle, for the selected set of main nozzles, as shown in FIG. 6, first, the drive to turn on the first valve device V1 (open state) is performed by the weft insertion control device 40, and the operating state of the first valve device V1 is set to the state of supplying the steady flow rate. Thereby, the supply of compressed air to the first main nozzle N1 via the first valve device V1 (the injection of compressed air from the first main nozzle N1) is started. However, the supply of the compressed air does not start immediately when the first valve device V1 is turned on. As also shown in the figure, it starts with a slight time lag (about 2°) with respect to the set first injection start timing.

[0080] Also, the flow rate of the compressed air supplied to the first main nozzle N1 (injected from the first main nozzle N1) does not reach the steady flow rate immediately after the supply of the compressed air to the first main nozzle N1 (the injection of compressed air from the first main nozzle N1) is started, but gradually increases toward the steady flow rate. And the flow rate reaches the steady flow rate at the crank angle of 100° as described above. Regarding the compressed air injected from the first main nozzle N1, since the flow rate and the pressure are in a proportional relationship, the pressure rises proportionally as the flow rate increases as described above. And the pressure becomes the pressure corresponding to the steady flow rate at the same crank angle of 100° at the timing when the flow rate reaches the steady flow rate, as shown in FIG. 6.

[0081] Also, when the crank angle θ reaches 80° (the second injection start timing) between the start of the injection of the compressed air at the first main nozzle N1 and the time when the flow rate reaches the steady flow rate, the drive of the second valve device 21 by the weft insertion control device 40 is started.

[0082] Regarding the drive, more specifically, when the crank angle θ reaches 80°, the drive control device 40 turns on only the small-flow valve 23 among the constant-flow valve 22 and the small-flow valve 23 in the second valve device 21 (open state), and the operating state of the second valve device 21 is set to the small-flow state. Thereby, in the second valve device 21, the supply of compressed air to the second main nozzle 20 through the small-flow valve 23 as described above is started. And accordingly, the injection of compressed air from the second main nozzle 20 is started.

[0083] However, the supply of compressed air from the second valve device 21 (the injection of compressed air from the second main nozzle 20) also starts with a slight time lag with respect to the second injection start timing, similar to the first main nozzle N1 side. Also, the flow rate of the compressed air supplied to the second main nozzle 20 (injected from the second main nozzle 20) does not immediately reach the flow rate assumed in the small-flow valve 23 as the small flow rate, but gradually increases toward the small flow rate.

[0084] And when 10° of the initial injection period has elapsed after the operating state of the second valve device 21 is set to the small-flow state in this way, that is, when the crank angle θ reaches 90°, the drive control device 40 turns on the constant-flow valve 22 in the second valve device 21 (open state). Thereby, the second valve device 21 is in a state where its operating state is switched from the small-flow state to the state of supplying the above-described constant flow rate. As a result, the supply of compressed air to the second main nozzle 20 is switched from the supply through the small-flow valve 23 to the supply through the constant-flow valve 22. And regarding the flow rate of the compressed air supplied to the second main nozzle 20 through the constant-flow valve 22, it also reaches the constant flow rate at the same crank angle 100° as the timing at which the first main nozzle N1 side reaches the constant flow rate as described above.

[0085] Thus, regarding the supply of compressed air by the second valve device 21, the supply first starts with the operating state of the second valve device 21 being the low flow rate state where the degree of rise in the flow rate is gentler than the state of supplying the steady flow rate, and after the elapse of a preset initial injection period, it is switched to the state of supplying the steady flow rate. Thereby, the flow rate of the supplied compressed air first rises more gently than when the operating state of the second valve device 21 is the state of supplying the steady flow rate, and after passing through the gentle rising portion, it rises to reach the steady flow rate in a manner corresponding to the state of supplying the steady flow rate. As a result, the time from when the supply of compressed air starts at the second injection start timing until the flow rate of the compressed air reaches the steady flow rate becomes longer compared to the case where the operating state of the second valve device 21 is only the state of supplying the steady flow rate.

[0086] And the pressure of the compressed air injected from the second main nozzle 20 also rises in the same manner as the rise in the flow rate described above, as shown in FIG. 6. Moreover, since the initial injection period is set based on the crank angle difference between the first injection start timing and the second injection start timing, and the crank angle at which the flow rate of the compressed air supplied to the first main nozzle N1 (injected from the first main nozzle N1) reaches the steady flow rate as described above, the pressure of the compressed air injected from the second main nozzle 20 does not precede the rise in the pressure on the first main nozzle N1 side, and reaches the pressure corresponding to the steady flow rate (the same as the pressure of the compressed air injected from the first main nozzle N1) at the point when the flow rate reaches the steady flow rate. Therefore, since the pressure of the compressed air injected from the second main nozzle 20 does not exceed the pressure of the compressed air injected from the first main nozzle N1, it is possible to suppress the occurrence of disturbance in the yarn posture of the weft yarn being inserted.

[0087] Also, in the process of the flow rate of the compressed air jetted from the first main nozzle N1 and the second main nozzle 20 rising as described above, when the crank angle θ reaches 90° (the third injection start timing), the drive to turn on the third valve device 31 (open state) is also performed by the injection control device 40, and the operating state of the third valve device 31 is also set to the state of supplying the steady flow rate. Thereby, the supply of compressed air to the third main nozzle 30 via the third valve device 31 (the injection of compressed air from the third main nozzle 30) is also started. Incidentally, the flow rate of the compressed air supplied to the third main nozzle 30 reaches the steady flow rate at a timing slightly after the crank angle of 100°.

[0088] And thus, after the flow rate of the compressed air supplied to (jetted from) each of the first main nozzle N1, the second main nozzle 20, and the third main nozzle 30 reaches the steady flow rate as described above, until the injection end timing, the injection state at the steady flow rate, that is, the steady state of injection is continued.

[0089] Then, when the crank angle θ reaches 180°, which is the injection end timing, the drive to turn off the first valve device V1, the second valve device 21, and the third valve device 31 (closed state) is performed by the injection control device 40. Thereby, the supply of compressed air to the corresponding main nozzle via the first valve device V1, the second valve device 21, and the third valve device 31 is stopped.

[0090] Even if the supply of compressed air to each main nozzle is stopped as described above, compressed air remains in the piping connecting each valve device to the main nozzle corresponding to each valve device. And regarding the pressure (residual pressure) of the compressed air remaining in each piping, since the length of the second piping H2 (the piping on the second main nozzle 20 side) is shorter than the length of the first piping H1 (the piping on the first main nozzle N1 side), the residual pressure in the second piping H2 will escape (become zero) earlier than the residual pressure in the first piping H1. Therefore, the time until the residual pressure in each piping escapes (the time until the pressure of the compressed air jetted from each main nozzle becomes zero) is shorter on the second main nozzle 20 side (the second piping H2 side) than on the first main nozzle N1 side (the first piping H1 side) as shown in FIG. 6. Thus, damage to the weft yarn due to the residual pressure on the second main nozzle 20 side (inside the second piping H2) is prevented.

[0091] As described above, one embodiment of an air jet loom equipped with a weft insertion device to which the present invention is applied (hereinafter referred to as "the above embodiment") has been described. However, the present invention is not limited to the above embodiment, and it can also be implemented in other embodiments (modification examples) as follows.

[0092] (1) Regarding the weft insertion device, in the above embodiment, the weft insertion device 3 is configured such that two auxiliary main nozzles N2, N2 are provided corresponding to each of the plurality of first main nozzles N1. That is, the weft insertion device 3 is configured such that each set of main nozzles includes two auxiliary main nozzles N2, N2. Furthermore, the weft insertion device 3 is configured such that the downstream auxiliary main nozzle N2 among the two auxiliary main nozzles N2, N2 in each set is the second main nozzle 20 to which the second valve device 21 configured as described above is connected. However, in the present invention, the weft insertion device, even when it includes two auxiliary main nozzles, is not limited to being configured as in the above embodiment, and may be configured such that the upstream auxiliary main nozzle is the second main nozzle.

[0093] In that case, the valve device connected to the auxiliary main nozzle on the downstream side may be the same as the third valve device 31 in the above embodiment, and may be configured to have only an operating state that supplies the steady flow rate. Further, in the present invention, when each set of main nozzles includes two auxiliary main nozzles, since the second main nozzle (the auxiliary main nozzle to which the second valve device including the low-flow valve is connected) is not limited to one, in addition to the auxiliary main nozzle on the upstream side, the auxiliary main nozzle on the downstream side may also be the second main nozzle.

[0094] (2) Regarding the second valve device, in the above embodiment, the second valve device 21 is configured by combining the low-flow valve 23 and the steady-flow valve 22, and on top of that, the low-flow valve 23 and the steady-flow valve 22 are integrally provided with respect to the second main nozzle 20. Specifically, the low-flow valve 23 is directly attached to the nozzle body portion 25 of the second main nozzle 20, and the steady-flow valve 22 is configured in such a manner that the nozzle body portion 25 also serves as a part thereof. However, in the present invention, the second valve device is not limited to being configured in such a way.

[0095] For example, regarding the steady-flow valve, a portion that was constituted by the nozzle body portion in the above embodiment is formed by a member separate from the nozzle body portion, and after configuring the steady-flow valve separately from the second main nozzle (nozzle body portion), the steady-flow valve may be directly attached to the nozzle body. Further, regarding the low-flow valve, similar to the steady-flow valve in the above embodiment, a portion that was formed by a member separate from the nozzle body portion as the valve housing portion in the above embodiment is omitted, and after forming the nozzle body portion so that a similar portion is included in the nozzle body portion, the low-flow valve may be configured in such a manner that a part of the nozzle body portion of the second main nozzle also serves as a part thereof (valve housing portion).

[0096] Also, in the case where the low-flow valve is configured separately from the second main nozzle (nozzle body) as in the above embodiment and / or the constant-flow valve is configured separately from the second main nozzle (nozzle body) as described above, the valve configured separately from the second main nozzle (nozzle body) is not limited to being provided in a manner directly attached to the second main nozzle as described above, and may be provided at a position separated from the second main nozzle. And in that case, the valve provided separately and the nozzle body of the second main nozzle are connected by a pipe or the like, and the pipe or the like becomes the second pipe. However, even in the case where the valve is provided separately in such a manner, in the present invention, the arrangement of the valve is such that the length of the second pipe is shorter than the first pipe H1 connecting the first valve device V1 and the first main nozzle N1.

[0097] (3) Regarding the second valve device, in the above embodiment, the second valve device 21 is configured by combining two electromagnetic valves (constant-flow valve 22 and low-flow valve 23) with different operating states. However, in the present invention, the second valve device is not limited to being configured by combining two such electromagnetic valves, and is configured such that the opening amount (opening degree) between the valve body and the valve seat can be adjusted (changed), and the flow rate of the fluid supplied can be changed by the opening degree, and may be configured by only one so-called throttle valve (throttle valve).

[0098] In that case, the low-flow valve is omitted, and a throttle valve is provided instead of the constant-flow valve. Regarding the installation method of the throttle valve, it may be directly attached to the nozzle main body as in the above embodiment, or it may be provided at a position separated from the nozzle main body (second main nozzle) as described above. When the second valve device is configured in this way, during the initial injection period from the second injection start timing, the second valve device is set to an opening degree (opening degree for low flow) such that the supplied flow rate becomes the flow rate assumed as the low flow rate, and when the initial injection period has elapsed, it is driven so that the supplied flow rate becomes the flow rate assumed as the constant flow rate (opening degree for constant flow rate). And in that case, regarding the operating state of the second valve device, the state with the opening degree for low flow is the low flow state, and the state with the opening degree for constant flow is the state of supplying the constant flow rate.

[0099] Also, regarding the second valve device 21, even when it is configured by combining two valves as in the above embodiment, for the valve provided for the low flow rate, instead of the electromagnetic valve (low flow rate valve) as in the above embodiment, it may be a throttle valve as described above so that the supplied flow rate can be changed. When the second valve device is configured to include a throttle valve, considering the responsiveness of the throttle valve, it is preferably configured to provide an electromagnetic valve upstream of the throttle valve (between the throttle valve and the supply source of compressed air), and the on / off (opening / closing) switching is performed by the electromagnetic valve.

[0100] (4) Regarding the low flow rate state during the initial injection period, in the above embodiment, the low flow rate valve 23 is configured to be in an open state capable of supplying the flow rate assumed as the low flow rate, and by keeping the low flow rate valve 23 in the open state throughout the initial injection period, the low flow rate state is realized. However, in the present invention, the low flow rate state during the initial injection period is not necessarily realized by keeping a single valve configured to be capable of supplying the flow rate assumed as the low flow rate in the open state throughout the initial injection period.

[0101] For example, in addition to the electromagnetic valve (first low flow rate valve) corresponding to the low flow rate valve 23 of the above embodiment, the second valve device may include an electromagnetic valve having the same configuration and configured such that the assumed flow rate is larger than that of the first low flow rate valve and smaller than the steady flow rate (second low flow rate valve). During the initial injection period, both low flow rate valves may be switched to realize the low flow rate state.

[0102] Specifically, the initial injection period is divided into two periods: a period from the second injection start timing (previous period) and a period from the end point of the previous period to the end point of the initial injection period (latter period). In the previous period, the first low flow rate valve is kept in the open state (the second low flow rate valve is in the closed state), and in the latter period, the second low flow rate valve is kept in the open state to realize the low flow rate state. And in that case, the degree of rise of the flow rate (pressure) in the low flow rate state may be different between the previous period and the latter period even during the initial injection period (the degree of rise is larger in the latter period). Thus, in the present invention, the low flow rate state is not limited to the flow rate (pressure) rising at a certain level throughout the initial injection period, and the flow rate (pressure) may be realized in a form that changes and rises during the initial injection period.

[0103] In addition, when configuring the second valve device so as to include two small-flow valves as described above, for example, two outlet channels may be formed to communicate with the annular channel 25c with different phases around the annular channel 25c, and both small-flow valves may be connected to their respective outlet channels. Further, the second valve device may be configured to include three or more small-flow valves configured to have different expected flow rates, and the degree of rise of the flow rate in the small-flow state may be changed to three or more. Further, when realizing the small-flow state by changing the degree of rise of the flow rate during the initial injection period in such a manner, instead of using a plurality of small-flow valves as described above, one throttle valve provided in place of the electromagnetic valve described above may be used to change the opening degree of the throttle valve so as to realize the small-flow state.

[0104] (5) Regarding the initial injection period, in the above-described embodiment, on the premise that the timing (second steady-state arrival timing) at which the flow rate of the compressed air injected from the second main nozzle 20 reaches the steady-state flow rate is made substantially coincide with the timing (first steady-state arrival timing) at which the flow rate of the compressed air injected from the first main nozzle N1 reaches the steady-state flow rate, various conditions regarding weft insertion are considered, and the initial injection period is set.

[0105] However, in the present invention, the second steady-state arrival timing is not limited to being determined so as to be substantially coincident with the first steady-state arrival timing as in the above-described embodiment, and may be determined as a timing earlier than the first steady-state arrival timing as long as there is no disturbance in the weft thread posture that would adversely affect weft insertion. Further, the second steady-state arrival timing may be determined as a timing later than the first steady-state arrival timing as long as the weft thread is not damaged or the like to the extent that it is regarded as a problem in relation to the traction by the injection of the first main nozzle. Then, the initial injection period is set based on the second steady-state arrival timing determined in such a manner.

[0106] Also, regarding the second injection start timing which is the start point of the initial injection period, in the above embodiment, the second injection start timing is set at a crank angle of 80°, which is 10° of crank angle after the crank angle of 70° which is the first injection start timing. However, even when the second injection start timing is set after the first injection start timing in such a manner, it is not limited to being set such that the difference from the first injection start timing is 10° of crank angle, and it may be appropriately set in consideration of the above conditions and the like. Further, the second injection start timing is not limited to being set after the first injection start timing, and it may be the same as the first injection start timing, or may be set before the first injection start timing as long as the disturbance of the weft yarn posture that adversely affects the weft insertion does not occur.

[0107] In the above embodiment, as described above, the third main nozzle 30 is provided upstream of the second main nozzle, and the third injection start timing set for the third main nozzle 30 (the third valve device 31) is set at a crank angle of 90°, which is 10° of crank angle after the crank angle of 80° which is the second injection start timing. However, the third injection start timing is not limited to being set after the second injection start timing in such a manner, and it may be the same as the second injection start timing, or may be set before the second injection start timing.

[0108] (6) With regard to the weft insertion device, in the above embodiment, the weft insertion device 3 is configured such that two auxiliary main nozzles N2, N2 (the second main nozzle 20 and the third main nozzle 30) are provided for each first main nozzle N1. However, the weft insertion device of the present invention is not limited to being configured to have two such auxiliary main nozzles. It may be configured to omit the third main nozzle, which is the upstream auxiliary main nozzle, and have only the second main nozzle, which is the downstream auxiliary main nozzle. Further, the weft insertion device may be configured to have three (or more) auxiliary main nozzles. And in that case, one or more of the plurality of auxiliary main nozzles are configured to be the second main nozzle.

[0109] Also, the weft insertion device to which the present invention is applied is not limited to being configured to have a plurality of first main nozzles N1 as in the above embodiment, and may be configured to have only one first main nozzle.

[0110] Note that the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention.

Explanation of Reference Numerals

[0111] 1 Air injection loom 2 Support stand 3 Weft insertion device 5 Stay F Frame of loom R Reed RH Reed holder MS Main shaft EN Encoder N1 Main nozzle (first main nozzle) N2 Auxiliary main nozzle V1 Valve device for main nozzle (first valve device) V2 Valve device for auxiliary main nozzle H1 Pipe (first pipe) H2 nozzle-side flow path (second pipe) 20 Second main nozzle 21 Second valve device 22 Constant flow rate valve 22a Valve body 22b Valve body drive unit 22b1 Plunger 22b2 Main body 23 Low flow rate valve 23a Valve body 23b Valve body drive unit 23b1 Plunger 23b2 Main body 23c Valve housing part 23c1 Valve seat 23c2 Accommodation space 23c3 Inflow path 23c4 Outflow path 25 Nozzle main body part 25a Through hole 25b Main flow path 25c Annular flow path 25d Introduction flow path 25e Pipe joint 25f Communication flow path 25g Annular end face (valve seat) 25h Derivation flow path 25k Sub-flow path 26 Pipe part 27 Thread guide 28 Mounting member 30 Third main nozzle 31 Third valve device 31a Valve body 31b Valve body drive unit 31b1 Plunger 31b2 Main body 35 Nozzle main body part 35a Through hole 35b Main flow path 35c Annular flow path 35d Introduction flow path 35e Pipe joint 35f Communication flow path 35g Annular end face (valve seat) 36 Pipe part 37 Thread guide 38 Mounting member 40 Weft insertion control device (control device) 41 Memory 42 Input setter

Claims

1. An air jet loom weft insertion device including a first main nozzle for weft insertion and a second main nozzle disposed upstream of the first main nozzle and functioning as an auxiliary main nozzle, wherein the first main nozzle is connected to a first valve device via a first pipe and the second main nozzle is connected to a second valve device via a second pipe shorter than the first pipe. In the weft insertion method of an air jet loom provided with a weft insertion device that supplies compressed air to each main nozzle by keeping each valve device open over an injection period from a preset injection start timing, the operating state of the second valve device is set to a low flow state in which a flow rate less than a steady flow rate, which is the flow rate in the steady state of injection, is supplied during a preset initial injection period starting from the injection start timing. A weft insertion method in an air jet loom, characterized by the above.

2. The weft insertion device includes a third main nozzle disposed upstream of the second main nozzle and connected to a third valve device. The third valve device is set to supply the steady flow rate over the injection period. A weft insertion method in an air jet loom according to claim 1, characterized by the above.

3. The second valve device is integrally provided for the second main nozzle. A weft insertion method in an air jet loom according to claim 1 or claim 2, characterized by the above.

4. An air jet loom weft insertion device including a first main nozzle for weft insertion and a second main nozzle disposed upstream of the first main nozzle and functioning as an auxiliary main nozzle, wherein the first main nozzle is connected to a first valve device via a first pipe and the second main nozzle is connected to a second valve device via a second pipe shorter than the first pipe. In the weft insertion device that supplies compressed air to each main nozzle by keeping each valve device open over an injection period from a preset injection start timing, the second valve device is configured to be able to change its operating state between a state of supplying a steady flow rate, which is the flow rate in the steady state of injection, and a low flow state in which a flow rate less than the steady flow rate is supplied. A memory that stores an initial injection period preset starting from the injection start timing, and a control device that switches the operating state of the second valve device, the control device setting the operating state of the second valve device in the initial injection period to the low flow rate state. The weft insertion device in an air injection type loom, characterized by the above. **Claim 5** The weft insertion device includes a third main nozzle disposed upstream of the second main nozzle and connected to a third valve device. The third valve device is set to supply the steady flow rate over the injection period. The weft insertion device in an air injection type loom according to claim 4, characterized by the above. **Claim 6** The second valve device is provided integrally with the second main nozzle. The weft insertion device in an air injection type loom according to claim 4 or claim 5, characterized by the above.

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