Weft insertion method and weft insertion device for air jet looms

Abstract

This invention provides a weft insertion method and device for an air-jet loom. In the air-jet loom equipped with the weft insertion device, a first main nozzle for weft insertion is connected to a first valve device via a first pipe, and a second main nozzle, serving as an auxiliary main nozzle, is connected to a second valve device via a second pipe shorter than the first pipe. In the weft insertion device, each valve device is kept open throughout the entire injection period from the start of the injection, and compressed air is supplied to each main nozzle. In this air-jet loom, damage to the weft yarn due to residual pressure can be prevented, and the disorder of the weft yarn's posture during weft insertion, which adversely affects weft insertion, can be suppressed. A key feature of this invention is that, in the aforementioned air-jet loom, during the initial injection period preset from the start of the injection, the operation state of the second valve device is set to a low-flow state, that is, a flow rate lower than the stable flow rate in the stable injection state.

Description

Technical Field

[0001] This invention relates to an air-jet loom equipped with a weft insertion device. The weft insertion device in the air-jet loom 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. During the entire jetting period starting from a preset jetting start time, the weft insertion device keeps each valve device in the open state and supplies compressed air to each main nozzle. Prior Technology

[0002] As a weft insertion device in an air-jet loom, there is, for example, the weft insertion device disclosed in Patent Document 1. This weft insertion device, in addition to a main nozzle that primarily assists in weft insertion, also has a series nozzle positioned upstream of the main nozzle in the weft insertion direction, functioning as an auxiliary main nozzle for weft insertion. That is, in this weft insertion device, the main nozzle and the series nozzle cooperate to perform one weft insertion.

[0003] Furthermore, in a typical loom, the main nozzle is mounted on a reed frame, which oscillates in the back-and-forth direction of the loom during weaving. On the other hand, the auxiliary main nozzle is supported by a shaft that is erected relative to the frame of the loom via a bracket or similar support, and is fixedly mounted on the loom.

[0004] Furthermore, the weft insertion device is equipped with solenoid valves, which are respectively provided with the main nozzle and the auxiliary main nozzle, for controlling the supply of compressed air to the main nozzle and the auxiliary main nozzle during the aforementioned weft insertion. In this weft insertion device, each solenoid valve is connected to the corresponding main nozzle or auxiliary main nozzle via piping. Based on this, during the entire injection period from a preset injection start time, each solenoid valve is kept in the open state, thereby supplying compressed air to the main nozzle and the auxiliary main nozzle to perform the aforementioned weft insertion.

[0005] [Previous Technical Documents] [Patent Literature] [Patent Document 1]: Japanese Patent Application Publication No. 2013-096038. Summary of the Invention

[0006] [The problem that the invention aims to solve] However, as disclosed in Patent Document 1, in a typical loom, the weft insertion device is configured such that the piping from the solenoid valve to the auxiliary main nozzle is longer than the piping to the main nozzle. Moreover, according to this structure, the pressure rise of the compressed air injected from the auxiliary main nozzle is more gradual than the pressure rise of the main nozzle, which has the advantage of suppressing the disorder of the weft yarn's posture.

[0007] However, in this configuration, the time until the residual pressure in the piping is completely released on the auxiliary main nozzle side is longer, thus causing damage to the weft yarn. More specifically, even if the solenoid valve, which is open during the injection process, is closed at the end of the injection, compressed air (residual pressure) remains in the piping to the main nozzle and auxiliary main nozzle at that moment. Therefore, until this residual pressure is completely released, an airflow corresponding to this pressure acts on the weft yarn connected to the main nozzle and auxiliary main nozzle. Furthermore, the time for this airflow generated by the residual pressure to act corresponds to the length of the piping. Therefore, in the configuration with a longer piping to the auxiliary main nozzle as described above, the airflow generated by the residual pressure acts on the weft yarn for a longer period on the auxiliary main nozzle side, sometimes resulting in damage to the weft yarn.

[0008] On the other hand, in conventional looms, there is a structure where the weft insertion device is configured such that the piping from the solenoid valve to the auxiliary main nozzle is shorter than the piping on the main nozzle side. Furthermore, in this structure, it is difficult to cause damage to the weft yarn due to airflow generated by residual pressure, as described above. However, in this structure, unlike the case where the piping on the auxiliary main nozzle side is longer, the pressure rise of the compressed air ejected from the auxiliary main nozzle is more rapid than the pressure rise of the main nozzle. Therefore, as a result, sometimes the yarn posture of the inserted weft yarn becomes disordered, adversely affecting the weft insertion process.

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

[0010] [Methods used to solve problems] The present invention is based on an air-jet loom equipped with a weft insertion device. The weft insertion device of the aforementioned air-jet loom 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. During the entire injection period starting from a preset injection start time, the aforementioned weft insertion device keeps each valve device in the open state and supplies compressed air to each main nozzle.

[0011] Based on this, the weft insertion method of the present invention is characterized in that, in an air jet loom equipped with a weft insertion device based on the above structure, during the initial jetting period preset from the jetting start time, the operation state of the second valve device is set to a low flow state, that is, a state in which a flow rate less than that in the stable jetting state, i.e., a stable flow rate, is supplied.

[0012] Furthermore, the "operating state" of the second valve device mentioned here refers to the mechanically determined state (open state) of the valve device. That is, this operating state is expressed in relation to the flow rate, just like the "supply flow rate state" mentioned above, but it is not based on the relationship with the actual flow rate of compressed air supplied from the valve device (actual flow rate). Rather, it refers to the mechanically open state as a result of the operation of the valve device, that is, the open state that is able to supply the pre-planned flow rate (planned flow rate).

[0013] More specifically, the valve device actuates at the start of the injection, entering a predetermined mechanically open state. However, the actual flow rate does not instantaneously reach the intended flow rate corresponding to the valve device's open state, but rather reaches the intended flow rate through a gradual increase. Thus, even though the valve device is mechanically open based on the intended flow rate, this state also includes a state where the actual flow rate is less than the intended flow rate. However, the "operating state" of the valve device described in this invention is not based on such a changing actual flow rate, but simply refers to the state of the valve device being in a mechanically open state determined by its relationship with the intended flow rate.

[0014] Based on this, "stable flow rate" refers to the flow rate under a stable injection state as described above, and more specifically, to the flow rate supplied from the valve device corresponding to each main nozzle when the injection becomes stable. Moreover, the stable injection state refers to the state in which the actual flow rate supplied from the valve device to the main nozzle during weft insertion becomes the intended flow rate.

[0015] Furthermore, regarding the "(pre-set) initial injection period" described above, this initial injection period is the period starting from the injection start time set for the second valve device, as described above, and is determined by considering various conditions related to weft insertion. These various conditions include: the relationship between the injection start time of the second valve device and the injection start time of the first valve device; the set pressure of the compressed air supplied to the second valve device; the set speed of the loom (spindle); and the length of the first piping that has a significant impact on the pressure rise characteristics of the compressed air injected from the first main nozzle.

[0016] Furthermore, in the weft insertion device of the present invention, the second valve device is configured to switch its operating state between a state supplying a stable flow rate, i.e., a flow rate in a stable injection state, and a state supplying a low flow rate, i.e., a flow rate less than that in the stable state. Moreover, the weft insertion device is characterized by comprising: a storage device for storing an initial injection period preset from the injection start time; and a control device for switching the operating state of the second valve device and setting the operating state of the second valve device during the initial injection period to the low flow rate state.

[0017] Furthermore, in the weft insertion method and weft insertion device of the present invention, the weft insertion device may also include a third main nozzle disposed upstream of the second main nozzle and connected to a third valve device, wherein the third valve device is configured to supply a stable flow rate throughout the injection process. Moreover, in the weft insertion method and weft insertion device of the present invention, the weft insertion device may also be configured such that the second valve device is integrally disposed relative to the second main nozzle.

[0018] [Invention Benefits] According to the present invention, the weft insertion device is configured as a second main nozzle, which serves as an auxiliary main nozzle, located upstream of the first main nozzle (main nozzle). It is connected to a corresponding second valve device via a pipe (second pipe) shorter than the pipe (first pipe) on the first main nozzle side. Therefore, with this structure, the aforementioned problem of weft yarn damage due to residual pressure on the second main nozzle (second pipe) side is less likely to occur.

[0019] Based on this, in this invention, during the initial injection period, starting from the beginning of the injection period (i.e., the injection start time), the second valve device is set to a low-flow state, that is, a state that supplies a flow rate less than the stable flow rate. Therefore, during this initial injection period, compared to conventional weft insertion devices where the second valve device is configured to supply the stable flow rate throughout the injection period, the supply flow rate of compressed air to the second main nozzle is less than the stable flow rate. Thus, according to this invention, since the pressure rise of the compressed air injected from the second main nozzle becomes gradual during the initial injection period, it is possible to suppress the disorder of the weft yarn's posture and minimize problems that could adversely affect weft insertion.

[0020] Furthermore, in the weft insertion device of the present invention, since the third valve device connected to the auxiliary main nozzle (third main nozzle) arranged upstream of the second main nozzle is set to supply the stable flow rate throughout the entire injection period, the structure of the weft insertion device can be simplified as a whole.

[0021] More specifically, when the weft insertion device has two or more auxiliary main nozzles upstream of the first main nozzle, even if not all auxiliary main nozzles are set as the second main nozzle (the auxiliary main nozzle connected to the second valve device), but the auxiliary main nozzles located downstream (less than the total number) are set as the second main nozzle, and the remaining auxiliary main nozzles on the upstream side are set as the third main nozzle connected to the third valve device, the objective effect of the present invention can still be achieved.

[0022] Furthermore, as described above, the third valve device is simply configured to supply a stable flow rate and is merely a solenoid valve that switches between open and closed states. Therefore, compared to the second valve device, which is configured to change the supply flow rate, the third valve device has a simpler structure. Consequently, when there are two or more auxiliary main nozzles, the structure of the weft insertion device can be further simplified compared to the case where all auxiliary main nozzles are set as the second main nozzle.

[0023] Furthermore, in the weft insertion device of the present invention, the weft insertion device is configured such that the second valve device is integrally set with respect to the second main nozzle, thereby making it less likely to cause the aforementioned problem of weft yarn damage due to residual pressure. On this basis, the present invention makes a more effective contribution in suppressing the aforementioned disorder of yarn posture.

[0024] More specifically, by configuring the weft insertion device so that the second valve device connected to the second main nozzle is integrally provided with respect to the second main nozzle, the second piping system connecting the second main nozzle and the second valve device becomes extremely short compared to the case where the second valve device is located separately from the second main nozzle. Moreover, in this case, it is much less likely that the weft yarn will be damaged due to residual pressure in the second piping.

[0025] However, shortening the second piping in this way causes the pressure rise of the compressed air at the second main nozzle side from the start of injection to become more rapid. Therefore, by applying the present invention, which enables a smoother rise in the pressure of the compressed air at the second main nozzle side, to a weft insertion device configured in this way, the present invention functions more effectively in suppressing the aforementioned yarn posture disorder. Simple Explanation of the Diagram

[0026] [Figure 1] is a front view of the weft insertion device of an air jet loom according to one embodiment of the present invention. [Figure 2] is a top view showing the main parts of the weft insertion device in Figure 1. [Figure 3] is a partial sectional top view of the main part in Figure 2. [Figure 4] is a cross-sectional view along line AA in Figure 2. [Figure 5] is an explanatory diagram showing the weft insertion device in Figure 1. [Figure 6] is a timing diagram showing the operating states of the first valve device, the second valve device and the third valve device in one embodiment of the present invention, and a diagram showing the pressure waveforms of the compressed air injected from the first main nozzle, the second main nozzle and the third main nozzle. Implementation

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

[0028] Figure 1 shows the weft insertion device 3 in the air-jet loom 1 of the present invention, and shows the peripheral portion of the main nozzle in the weft insertion device 3. Moreover, as shown in the figure, in addition to having a first main nozzle N1 that mainly helps to insert the weft yarn, the weft insertion device 3 also has an auxiliary main nozzle N2 that is positioned upstream of the first main nozzle N1 in the weft insertion direction to assist the insertion of the first main nozzle N1.

[0029] Furthermore, in the illustrated example, the weft insertion device 3 is a multi-colored weft insertion device 3 with multiple first main nozzles N1. Moreover, in this weft insertion device 3, a group of two auxiliary main nozzles N2, N2 are provided corresponding to each first main nozzle N1. Regarding the two auxiliary main nozzles N2, N2 in each group, the auxiliary main nozzle disposed on the upstream side in the weft insertion direction will be referred to as the upstream auxiliary main nozzle N2, and the auxiliary main nozzle disposed on the downstream side will be referred to as the downstream auxiliary main nozzle N2.

[0030] Furthermore, in this weft insertion device 3, each first main nozzle N1 is mounted on a reed frame RH on which the reed R is mounted, and the reed frame RH oscillates in the front-to-back direction of the loom during weaving. On the other hand, in the illustrated example, the two auxiliary main nozzles N2, N2 of each group are connected by a stay 5 and supported by a support frame 2 erected on the frame F of the loom via the stay 5. That is, each auxiliary main nozzle N2 is fixedly mounted on the loom. In addition, in each group, the upstream and downstream auxiliary main nozzles N2, N2 are arranged in the axial direction of each auxiliary main nozzle N2, and their axes are aligned when viewed along the axial direction of each auxiliary main nozzle N2. Based on this, each auxiliary main nozzle N2 is arranged such that the axis of each auxiliary main nozzle N2 points to the rear end of the corresponding first main nozzle N1.

[0031] Furthermore, the weft insertion device 3 is equipped with a valve device, which includes a solenoid valve (solenoid opening and closing valve) corresponding to each main nozzle for controlling the supply of compressed air to the first main nozzle N1 and the auxiliary main nozzle N2 respectively.

[0032] More specifically, the valve device (first valve device V1) for the first main nozzle N1 is the first valve device described in this invention, and a plurality of such devices are provided in such a manner that each corresponds to a plurality of first main nozzles N1. Furthermore, each first main nozzle N1 is mounted on a reed frame RH that is driven by a swing motion, and correspondingly, each first valve device V1 is fixedly mounted relative to the frame F of the loom. Moreover, each first valve device V1 is connected to its corresponding first main nozzle N1 via a pipe serving as a first piping H1.

[0033] Furthermore, a plurality of valve devices V2 for auxiliary main nozzles N2 are provided in a manner corresponding to each auxiliary main nozzle N2. In this embodiment, the valve device V2 is integrally provided with each corresponding auxiliary main nozzle N2, as will be explained in detail below. Therefore, the piping connecting the valve device V2, which is integrally provided with respect to the auxiliary main nozzle N2, to the auxiliary main nozzle N2 is shorter than the piping (first piping H1) connecting the first main nozzle N1 on the reed RH to the first valve device V1 on the frame F.

[0034] Furthermore, in the weft insertion device 3 configured as described above, in each weaving cycle, the valve devices (first valve device V1, valve device V2) provided relative to the selected first main nozzle N1 and its corresponding auxiliary main nozzle N2 are set to the open state at a predetermined injection start time, thereby supplying compressed air to the first main nozzle N1 and each auxiliary main nozzle N2, and injecting compressed air from the first main nozzle N1 and each auxiliary main nozzle N2 to insert the weft yarn. Based on this, in this embodiment, the injection start time for setting each valve device (first valve device V1, valve device V2) to the open state is set as follows: first, compressed air is injected from the first main nozzle N1, then the injection of compressed air begins in the order of the downstream auxiliary main nozzle N2, and finally the upstream auxiliary main nozzle N2.

[0035] In the air-jet loom 1 equipped with the weft insertion device 3 as described above, in this invention, the weft insertion device 3 is configured such that the valve device V2 provided relative to the auxiliary main nozzle N2 corresponding to each first main nozzle N1 includes a second valve device. This second valve device can not only establish a flow rate (stable flow rate) supplied to the auxiliary main nozzle N2 under a stable jetting state, but also establish a flow rate (low flow rate state) that is less than the stable flow rate. Based on this, the invention is characterized in that the operating state of the second valve device is set to the low flow rate state during the initial jetting period, which is preset from the jetting start time.

[0036] Based on this, this embodiment uses the second valve device 21 as an example of a valve device V2 provided relative to the downstream auxiliary main nozzle N2 of each group. Therefore, the downstream auxiliary main nozzle N2 is equivalent to the second main nozzle 20 described in this invention. On the other hand, regarding the valve device V2 provided relative to the upstream auxiliary main nozzle N2 in each group, this valve device V2 is configured as a valve device (third valve device) 31 whose only operating state is to supply the stable flow rate. Moreover, the upstream auxiliary main nozzle N2 is structurally the same as the auxiliary main nozzle, but it is not the second main nozzle 20 but the third main nozzle 30.

[0037] Regarding the common structure of the two auxiliary main nozzles N2 and N2 (second main nozzle 20 and third main nozzle 30) in each group, since the structure of the auxiliary main nozzles is the same as the conventional structure, detailed description is omitted. However, the second main nozzle 20 and the third main nozzle 30 are constructed with the nozzle body 25 and 35 supplied with compressed air as the main body, corresponding to their respective main nozzles.

[0038] Furthermore, the second main nozzle 20 and the third main nozzle 30 are configured to include: thread guides 27 and 37 respectively mounted on the corresponding nozzle body portions 25 and 35; and tube portions 26 and 36 integrally provided with the nozzle body portions 25 and 35 in such a way that one end is respectively inserted into the nozzle body portions 25 and 35. Moreover, the nozzle body portions 25 and 35 corresponding to each main nozzle are provided with compressed air supply paths in a manner that communicate with through holes 25a and 35a containing a portion of the thread guides 27 and 37. In addition, regarding the nozzle body portions 25 and 35, the surface facing upward on the loom is called the upper surface, the surface facing downward is called the lower surface, the surface facing downstream in the weft insertion direction is called the front surface, and the surface facing upstream is called the rear surface. Furthermore, the two surfaces other than the upper surface, lower surface, front surface, and rear surface, that is, the surfaces parallel to the through holes 25a and 35a, are called side surfaces.

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

[0040] The supply flow path is configured to include: a main flow path 35b, which communicates with the through hole 35a; an annular flow path 35c (with a donut-shaped cross-section) formed around the main flow path 35b; and an inlet flow path 35d, which allows compressed air supplied from a compressed air supply source (not shown) to flow in (introduce). Furthermore, the supply flow path is configured to include a connecting flow path 35f, which opens on the side of the nozzle body 35 and connects the main flow path 35b and the annular flow path 35c.

[0041] More specifically, regarding this supply flow path, the connecting flow path 35f is formed by opening on one of the two aforementioned side surfaces of the nozzle body 35, and is formed by penetrating in a direction orthogonal to that side surface (width direction). Furthermore, the inner diameter of the connecting flow path 35f is approximately the same as the outer diameter of the annular flow path 35c that communicates with the connecting flow path 35f as described above. Moreover, the annular flow path 35c is formed around the main flow path 35b (enclosing the main flow path 35b) as described above. Therefore, the inner diameter of the connecting flow path 35f is naturally larger than the inner diameter of the main flow path 35b.

[0042] Furthermore, the main flow path 35b is formed to extend along the aforementioned width direction, communicating with the connecting flow path 35f at one end and communicating with the through hole 35a at the other end as described above, thus connecting the through hole 35a with the connecting flow path 35f. Therefore, in the supply flow path, the main flow path 35b connects the connecting flow path 35f with the through hole 35a. Additionally, the through hole 35a communicating with the main flow path 35b is the portion (flow path) internally equipped with the yarn guide 37 of the third main nozzle 30 and connected to the tube 36. Therefore, the inner diameter (flow path diameter) of the main flow path 35b determines the extent to which compressed air is supplied at a predetermined flow rate and a flow rate (the stable flow rate) determined in a manner that achieves the desired weft insertion. Furthermore, in the illustrated example, the diameter of the portion at one end of the main flow path 35b is formed to be slightly larger than the diameter of the portions other than that portion.

[0043] Furthermore, the annular flow path 35c is formed as an annular flow path around the main flow path 35b, as described above. Moreover, the annular flow path 35c is formed such that one end of the annular flow path 35c communicates with the connecting flow path 35f, as described above. Furthermore, the annular flow path 35c is formed such that, in the aforementioned width direction, the other end of the annular flow path 35c is located near the middle portion of the main flow path 35b. In addition, the annular flow path 35c is formed to surround the main flow path 35b, as described above, and the inner diameter of the annular flow path 35c is naturally larger than the inner diameter of the main flow path 35b. Therefore, in the nozzle body 35, between the connecting end of the annular flow path 35c communicating with the connecting flow path 35f and the connecting end of the main flow path 35b communicating with the connecting flow path 35f, there exists an annular end face (annular end face (valve seat) 35g) exposed in the connecting flow path 35f.

[0044] Furthermore, the inlet flow path 35d is formed to open on the aforementioned front surface of the nozzle body portion 35 and communicate with the aforementioned other end side of the annular flow path 35c. Moreover, a pipe fitting 35e for connecting to a supply pipe for supplying compressed air is installed on the inlet flow path 35d.

[0045] Furthermore, as described above, the third valve device 31 provided relative to the nozzle body 35 configured in this way is a valve device whose only operational state is supplying the stable flow rate. Structurally, it is the same as the first valve device V1, and is composed of a general solenoid valve. However, in the third valve device 31 of this embodiment, the portion other than the disc-shaped valve core 31a and the part that drives the valve core 31a, i.e., the valve core drive part 31b, is composed of a portion of the nozzle body 35. In other words, a portion of the nozzle body 35 also serves as a portion of the third valve device 31. Based on this, in the third valve device 31 configured in this way, the valve core drive part 31b is mounted in a manner fixed relative to the aforementioned side of the nozzle body 35.

[0046] Furthermore, the valve core drive unit 31b is mounted relative to the nozzle body 35 via a mounting member 38. Specifically, the mounting member 38 is mounted on one side of the nozzle body 35 in the form of covering the opening of the connecting flow path 35f. Moreover, in the plate-shaped portion of the mounting member 38 covering the connecting flow path 35f (opening portion), a through hole with an inner diameter smaller than the inner diameter of the connecting flow path 35f is formed at a position where the center of the through hole coincides with the center of the connecting flow path 35f (main flow path 35b) when viewed along the width direction.

[0047] Furthermore, the valve core drive unit 31b includes a plunger 31b1 that is displaced and driven in the axial direction by a solenoid (not shown) built into the main body 31b2, protruding from the main body 31b2. The valve core 31a is mounted on the front end of the plunger 31b1. The valve core drive unit 31b is mounted on the mounting member 38 such that the plunger 31b1 passes through the through hole in the mounting member 38, which is mounted on the nozzle main body 35 as described above.

[0048] Therefore, in the state where the valve core drive unit 31b is installed on the mounting member 38 (installation state), the valve core 31a is located within the communicating flow path 35f in the nozzle body 35. Furthermore, in this installation state, one end face of the valve core 31a faces the annular end face 35g in the nozzle body 35, and the other end face faces the mounting member 38. Additionally, the inner diameter of the through hole in the mounting member 38 is larger than the outer diameter of the (inserted) plunger 31b1, but smaller than the outer diameter of the valve core 31a.

[0049] Furthermore, the outer diameter of the valve core 31a is approximately the same as (slightly smaller than) the inner diameter of the connecting flow path 35f. Moreover, the thickness of the valve core 31a is smaller than the size of the connecting flow path 35f in the width direction. Therefore, in the above-described installation state, the valve core 31a can slide in the width direction by having its outer circumferential surface guided by the inner circumferential surface of the connecting flow path 35f. Moreover, the sliding of the valve core 31a is limited by the annular end face 35g in the nozzle body 35 and the mounting member 38. Based on this, the thickness of the valve core 31a is such that, when the valve core 31a slides towards and abuts against the mounting member 38, a gap is formed between the valve core 31a and the annular end face 35g to allow the flow of compressed air with a stable flow rate.

[0050] Furthermore, in the third valve device 31 configured as described above, with the valve core drive unit 31b mounted on the nozzle body 35, if the plunger 31b1 is driven to a state where the valve core 31a abuts against the annular end face 35g, the annular flow path 35c, which communicates with the inlet flow path 35d, and the main flow path 35b, which communicates with the through hole 35a where the yarn guide 37 is installed, become separated by the valve core 31a (non-connected state). Therefore, even when compressed air is supplied to the annular flow path 35c via the inlet flow path 35d, the compressed air will not flow towards the main flow path 35b, and compressed air from the third main nozzle 30 will not be ejected. Thus, in this structure, the annular end face 35g of the nozzle body 35 functions as the valve seat of the third valve device 31.

[0051] Furthermore, if the plunger 31b1 is driven to abut the valve core 31a against the mounting member 38, the aforementioned gap is created between the valve core 31a and the annular end face 35g, resulting in a connection between the annular flow path 35c and the main flow path 35b (connected state). Consequently, the compressed air supplied to the annular flow path 35c via the inlet flow path 35d flows towards the main flow path 35b, thereby injecting compressed air from the third main nozzle 30. Moreover, in this stable injection state, a stable flow rate of compressed air is injected from the third main nozzle 30. Furthermore, the state in which the valve core 31a is abutted against the mounting member 38 and the main flow path 35b is connected to the supply side with a gap equal to the size of the stable flow rate of compressed air is the aforementioned state of "(capable of forming) an operating state that supplies the stable flow rate."

[0052] Next, regarding the second valve device 21 provided relative to the second main nozzle 20, this second valve device 21 is also integrally provided with respect to the nozzle body portion 25 of the corresponding second main nozzle 20. Furthermore, the supply flow path in the nozzle body portion 25 of the second main nozzle 20 also includes the connecting flow path 25f, the main flow path 25b, the annular flow path 35c, and the guide flow path 25d, which are formed in the same manner as the connecting flow path 35f, the main flow path 35b, the annular flow path 35c, and the guide flow path 35d in the nozzle body portion 35 of the third main nozzle 30. Moreover, an annular end face 25g is exposed in the connecting flow path 25f within the supply flow path. Furthermore, in the second main nozzle 20, a pipe connector 25e is also installed relative to the guide flow path 25d in the nozzle body portion 25.

[0053] Based on this, the second valve device 21 is configured as described above to change its operating state between the state of supplying the stable flow and the state of supplying a small flow. In this embodiment, the operating states it can form are configured by combining two different solenoid valves. Moreover, the two solenoid valves are a solenoid valve (stable flow valve) 22 configured to form an operating state that is only the state of supplying the stable flow, and a solenoid valve (small flow valve) 23 configured to form an operating state that is only the state of supplying the small flow.

[0054] Furthermore, the flow stabilizing valve 22 is structurally identical to the third valve device 31, comprising a valve core drive portion 22b including a main body 22b2 and a plunger 22b1 driven by displacement via a solenoid built into the main body 22b2, a valve core 22a mounted at the front end of the plunger 22b1 in the valve core drive portion 22b, and a portion other than the valve core drive portion 22b that also serves as part of the flow stabilizing valve 22, i.e., part of the nozzle main body 25. Moreover, the flow stabilizing valve 22, like the third valve device 31, is in the form where the valve core drive portion 22b (main body 22b2) is mounted on the nozzle main body 25 via a mounting member 28. Furthermore, in the flow stabilizing valve 22, the valve core 22a can also slide within the aforementioned width direction within the communicating flow path 25f.

[0055] Furthermore, the low-flow valve 23 is configured in the same way as the stable-flow valve 22, comprising: a valve core drive unit 23b, which includes a main body 23b2 and a plunger 23b1 that is displaced in the axial direction by a solenoid built into the main body 23b2; and a valve core 23a, which is the front end of the plunger 23b1 installed in the valve core drive unit 23b.

[0056] The valve 22 for stable flow is configured to house the valve core 22a, and the portion with the valve seat (annular end face 25g) is part of the nozzle body 25. The valve 23 for low flow is configured to include a valve housing 23c separate from the nozzle body 25, and a valve seat 23c1 is formed in the valve housing 23c to house the valve core 23a. That is, the valve 23 for low flow is configured by combining the valve core drive portion 23b and the valve housing portion 23c.

[0057] More specifically, the valve housing 23c is a block-shaped component with a relatively thick thickness. Furthermore, the valve housing 23c includes: a receiving space 23c2 for receiving the valve core 23a; an inflow passage 23c3 connected to the receiving space 23c2 and supplied with compressed air from a supply source; and an outflow passage 23c4 connected to the receiving space 23c2 and used to allow the compressed air flowing into the receiving space 23c2 from the inflow passage 23c3 to flow out.

[0058] The receiving space 23c2 is formed as a bottomed hole that opens only on one of the two end faces of the valve housing portion 23c in the thickness direction, and extends through the valve housing portion 23c in the aforementioned thickness direction. Furthermore, the receiving space 23c2 is circular when viewed along the aforementioned thickness direction, and its inner diameter is slightly larger (approximately the same) than the outer diameter of the valve core 23a. Moreover, the bottom surface of the receiving space 23c2 is located near the approximate middle of the valve housing portion 23c in the aforementioned thickness direction. That is, in the aforementioned thickness direction, the size (depth dimension) of the receiving space 23c2 is approximately half the size of the valve housing portion 23c. However, the depth dimension of the receiving space 23c2 is naturally larger than the thickness dimension of the valve core 23a it houses.

[0059] Furthermore, the outflow path 23c4 is formed with an opening on one end face of one of the two end faces of the valve housing 23c and communicates with the receiving space 23c2. When viewed along the thickness direction, the outflow path 23c4 is formed at a position where the center of the path coincides with the center of the receiving space 23c2. The inner diameter (flow path diameter) of the outflow path 23c4 is naturally smaller than the inner diameter of the receiving space 23c2, and is large enough to supply compressed air at a flow rate less than the stable flow rate. Moreover, in the valve housing 23c, the portion of the bottom surface of the receiving space 23c2 excluding the opening of the outflow path 23c4 forms the valve seat 23c1.

[0060] Furthermore, at the location where the receiving space 23c2 separates from the outflow path 23c4 in the radial direction, the inflow path 23c3 opens at the other end face of the valve housing portion 23c and is formed parallel to the outflow path 23c4. Moreover, the inflow path 23c3 is formed such that, when viewed in the thickness direction, its center is located near the periphery of the receiving space 23c2. Therefore, the inflow path 23c3 on the receiving space 23c2 side opens approximately halfway down the bottom surface.

[0061] Furthermore, in the low-flow valve 23, the valve core drive portion 23b is installed in the valve housing portion 23c, which is configured in this way, such that the valve core 23a is located within the receiving space 23c2 in the valve housing portion 23c. Moreover, as described above, the depth dimension of the receiving space 23c2 in the valve housing portion 23c is larger than the thickness dimension of the valve core 23a. Therefore, with the valve core drive portion 23b installed in the valve housing portion 23c, the valve core 23a can slide within the receiving space 23c2. This sliding is restricted by the valve seat 23c1 opposite to the valve core 23a and the main body 23b2 of the valve core drive portion 23b. Based on this, the thickness dimension of the valve core 23a is such that, when the valve core 23a slides towards the main body 23b2 and abuts against the main body 23b2, a gap is formed between the valve core 23a and the valve seat 23c1 sufficient to allow the low-flow compressed air to flow.

[0062] Furthermore, the low-flow valve 23, which is configured such that the valve core drive part 23b is mounted on the valve housing part 23c, is fixed relative to the nozzle body part 25 with the other end face of the valve housing part 23c abutting against the upper surface of the nozzle body part 25. Moreover, regarding this mounting, in the aforementioned width direction, the mounting is performed as follows: the position of the inflow path 23c3 in the valve housing part 23c coincides with the position of the other end portion of the annular flow path 25c in the nozzle body part 25 (the position connected by the inlet flow path 25d), and the outflow path 23c4 is located on the other end face side of the nozzle body part 25 (opposite to the side where the stable flow valve 22 is mounted) of the inflow path 23c3.

[0063] Based on this, the nozzle body 25, where the low-flow valve 23 is installed, has an outlet flow path 25h that connects the annular flow path 25c of the nozzle body 25 to the inflow flow path 23c3 in the valve housing 23c, and a secondary flow path 25k that connects the outflow flow path 23c4 in the valve housing 23c to the main flow path 25b. Furthermore, the outlet flow path 25h has an inner diameter approximately the same as the inflow flow path 23c3, and its direction is aligned with the direction (vertical direction) orthogonal to the upper surface of the nozzle body 25. Therefore, the connection position of the outlet flow path 25h with the annular flow path 25c is the position of the other end of the annular flow path 25c in the width direction, and is a position different from the position connected to the inlet flow path 25d in the circumferential direction of the annular flow path 25c. Furthermore, the secondary flow path 25k has an inner diameter that is approximately the same as that of the outflow flow path 23c4, and is the same as that of the outlet flow path 25h, so that the direction of the flow path is consistent with the above-mentioned vertical direction.

[0064] Furthermore, when the second valve device 21 and the nozzle body 25 configured in this way are integrally provided, the low-flow valve 23 is configured such that, as described above, the outflow path 23c4 is connected to the main flow path 25b in the nozzle body 25 via the secondary flow path 25k and the through-hole 25a via the main flow path 25b. In the stable flow valve 22, as described above, the portion other than the valve core drive portion 22b is formed by a part of the nozzle body 25. Therefore, the portion of the main flow path 25b of the nozzle body 25 on the connecting flow path 25f side becomes a flow path (valve-side flow path) forming part of the second valve device 21. In other words, the main flow path 25b is composed of the valve-side flow path in the second valve device 21 and the nozzle-side flow path (nozzle-side flow path (second piping H2)) that connects the valve-side flow path to the through-hole 25a.

[0065] Furthermore, the secondary flow path 25k is connected to the nozzle-side flow path (second piping H2). Therefore, it can be said that the second valve device 21 is connected to the through hole 25a in the second main nozzle 20, where the yarn guide 27 is installed, via the nozzle-side flow path (second piping H2) in the main flow path 25b. Thus, this nozzle-side flow path (second piping H2) corresponds to the second piping described in this invention. Moreover, since the second piping H2 is formed inside the nozzle body 25 of the second valve device 21, which is integrally formed with the second valve device 21, it is significantly shorter than the piping (first piping H1) that connects the first main nozzle N1 on the reed frame RH to the first valve device V1 on the frame F, as described above.

[0066] Furthermore, in the second valve device 21 configured as described above, when the valve core 23a in the low-flow valve 23 abuts against the valve seat 23c1 in the valve housing 23c, and when the valve core 22a in the stable-flow valve 22 abuts against the mounting component 28, then, similar to the third valve device 31, the compressed air supplied from the inlet flow path 25d to the annular flow path 25c flows into the main flow path 25b through the gap between the valve core 22a and the valve seat (annular end face 25g). Moreover, the operating state of the second valve device 21 is to supply the stable-flow compressed air.

[0067] On the other hand, if the valve core 22a of the stable flow valve 22 is in contact with the valve seat (annular end face 25g), and the valve core 23a of the low flow valve 23 is in contact with the main body 23b2, then the compressed air supplied to the annular flow path 25c as described above will not flow into the main flow path 25b on the stable flow valve 22 side, but will instead flow from the annular flow path 25c through the outlet flow path 25h into the inflow flow path 23c3 of the low flow valve 23. Furthermore, on the low flow valve 23 side, the compressed air flowing into the inflow flow path 23c3 flows into the outlet flow path 23c4 through the gap between the valve core 23a and the valve seat 23c1. Based on this, the compressed air flowing in the outlet flow path 23c4 flows into the main flow path 25b through the secondary flow path 25k. Thus, when the second valve device 21 is in operation, the supplied compressed air flows into the main flow path 25b through the low flow valve 23 instead of the stable flow valve 22. Moreover, the operation state of the second valve device 21 is the supply of the low flow state, that is, the low flow state.

[0068] Furthermore, in any operating state, compressed air flows into the main flow path 25b as described above, thereby injecting compressed air into the second main nozzle 20 corresponding to the flow rate. Additionally, even when the valve core 22a of the stabilizing flow valve 22 is in contact with the mounting component 28, and even when the valve core 23a of the low-flow valve 23 is in contact with the body 23b2, the stabilizing flow valve 22 side is a state where compressed air flows more easily than the low-flow valve 23 side due to the relationship between the size of the gap between the valve core and valve seat of both the stabilizing flow valve 22 and the low-flow valve 23, and the diameter of the flow path connected to that gap. Therefore, compressed air mainly flows into the main flow path 25b from the stabilizing flow valve 22 side. Thus, this operating state is also a state that supplies compressed air for the stabilizing flow rate.

[0069] Furthermore, as shown in Figure 5, the weft insertion device 3 configured as described above includes a weft insertion control device 40, which serves as a control device for controlling the operational state of the valve devices (first valve device V1, second valve device 21, and third valve device 31) in each main nozzle (first main nozzle N1, second main nozzle 20, and third main nozzle 30). This weft insertion control device 40 includes a storage unit 41 for storing weft insertion conditions, which include the injection period of compressed air from each main nozzle (first main nozzle N1, second main nozzle 20, and third main nozzle 30). In addition, the weft insertion device 3 of this embodiment includes a plurality of first main nozzles N1 and two auxiliary main nozzles N2, N2 (second main nozzle 20 and third main nozzle 30) provided relative to each first main nozzle N1. Furthermore, the weft insertion conditions stored in the storage unit 41 also include the weft insertion sequence for selecting which group of main nozzles performs injection (weft insertion) in each weaving cycle.

[0070] Furthermore, regarding the jetting period included in the weft insertion conditions, the storage device 41 stores the jetting start time and jetting end time corresponding to the jetting period. However, the jetting start time and jetting end time are set by the rotation angle (crank angle) θ of the main shaft MS of the loom. Moreover, the weft insertion conditions also include an initial jetting period, which is set taking into account various conditions related to weft insertion, starting from the initial jetting start time set for the second valve device 21. That is, the initial jetting period is stored in the storage device 41 as one of the weft insertion conditions.

[0071] Furthermore, the air-jet loom 1 is equipped with an input setting device 42 for inputting and setting the aforementioned weft insertion conditions. This input setting device 42 is also connected to a storage unit 41 in the weft insertion control device 40. The aforementioned weft insertion conditions are input and set via the input setting device 42, and these set weft insertion conditions are stored in the storage unit 41. Moreover, the air-jet loom 1 is equipped with an encoder EN that detects the rotation angle of the main shaft MS and outputs a crank angle signal θ. This encoder EN is also connected to the weft insertion control device 40, outputting a crank angle signal θ corresponding to the detected rotation angle of the main shaft MS to the weft insertion control device 40.

[0072] Furthermore, the weft insertion control device 40 is configured such that, regarding the group of main nozzles selected in each weaving cycle, the operating states of the first valve device V1, the second valve device 21, and the third valve device 31 are controlled based on the weft insertion conditions stored in the storage 41 and the crank angle signal θ from the encoder EN.

[0073] Furthermore, regarding the injection start timings set for the first valve device V1, the second valve device 21, and the third valve device 31, in this embodiment, firstly, the injection start timing (first injection start timing) set for the first valve device V1 is set at a crankshaft angle of 70°. Based on this, as described above, the second main nozzle 20 (the aforementioned downstream auxiliary main nozzle N2) begins injection after the first main nozzle N1 begins injection; therefore, the injection start timing (second injection start timing) set for the second valve device 21 is set at a crankshaft angle of 80°, which is a crankshaft angle later than the 70° crankshaft angle used as the first injection start timing. Furthermore, the third main nozzle 30 (the aforementioned upstream auxiliary main nozzle N2) begins injection last; therefore, the injection start timing (third injection start timing) set for the third valve device 31 is set at a crankshaft angle of 90°, which is a crankshaft angle later than the 80° crankshaft angle used as the second injection start timing.

[0074] Furthermore, in this embodiment, the timing of the end of spraying for each main nozzle (first main nozzle N1, second main nozzle 20, and third main nozzle 30) is the same. Therefore, the timing of the end of spraying for the first valve device V1, the second valve device 21, and the third valve device 31 is all set to the same crankshaft angle, i.e., crankshaft angle 180°.

[0075] Furthermore, as described above, the operating state of the second valve device 21 is set to the low-flow state during the initial injection period, which is preset from the second injection start time. That is, during the initial injection period from the second injection start time, the second valve device 21 is set to operate in a state where only the low-flow valve 23, which forms the low-flow state, is open. At the end of the initial injection period, it switches to a state of supplying compressed air with a stable flow rate, that is, the stable flow valve 22 is open. Based on this, in this embodiment, considering various conditions related to weft insertion, the initial injection period is set such that the timing when the flow rate of compressed air injected from the second main nozzle 20 reaches the stable flow rate is approximately the same as the timing when the flow rate of compressed air injected from the first main nozzle N1 reaches the stable flow rate.

[0076] Specifically, in the air-jet loom 1 of this embodiment, based on the relationship between the loom's rotation speed set for weaving and the pressure of the compressed air supplied to each main nozzle, the timing when the flow rate of compressed air ejected from the first main nozzle N1 reaches the stable flow rate is at a crank angle of 100°. Furthermore, as described above, the timing when the second main nozzle 20 begins ejection is a time 10° after the timing when the first main nozzle N1 begins ejection.

[0077] Furthermore, regarding the increase in the flow rate of compressed air ejected from the second main nozzle 20, the degree of increase in the flow rate of compressed air from the start of ejection in the low-flow state of the second valve device 21 (the increase in flow rate per unit time) and the degree of increase in the flow rate of compressed air after switching from the low-flow state to the state of supplying the stable flow rate are determined in advance through experiments, etc.

[0078] Furthermore, based on this, if the supply of a low-flow state switches to a stable-flow state at some point after the second injection start time (crankshaft angle 80°), it is determined whether the flow rate of compressed air injected from the second main nozzle 20 at the desired time (crankshaft angle 100° in this embodiment) reaches the stable-flow state. Moreover, the period from the second injection start time up to this determined switching time is called the initial injection period. In this embodiment, the switching time determined in this way is crankshaft angle 90°, therefore the initial injection period is set to a period when the crankshaft angle is 10°.

[0079] In the weft insertion device 3 configured as described above, if the crank angle θ reaches 70° (the first injection start time) in each weaving cycle, then regarding the selected main nozzle group, as shown in Figure 6, the weft insertion control device 40 first drives the first valve device V1 to the on state (open state), and the operating state of the first valve device V1 is set to supply the stable flow rate. Thus, compressed air begins to be supplied to the first main nozzle N1 via the first valve device V1 (compressed air is injected from the first main nozzle N1). However, the supply of compressed air does not begin immediately after the first valve device V1 becomes on, but rather, as shown in the figure, begins with a slight time delay (approximately 2°) relative to the set first injection start time.

[0080] Furthermore, the flow rate of compressed air supplied to (or ejected from) the first main nozzle N1 does not immediately reach the stable flow rate after the supply of compressed air to (or the ejection of compressed air from) the first main nozzle N1 begins, but rather gradually increases towards the stable flow rate. Moreover, as described above, the stable flow rate is reached at a crank angle of 100°. Furthermore, regarding the compressed air ejected from the first main nozzle N1, since the flow rate and pressure are proportional, the pressure increases proportionally with the increase of the flow rate, as described above. Moreover, as shown in FIG6, the pressure at the crank angle of 100°, which coincides with the time when the flow rate reaches the stable flow rate, corresponds to the stable flow rate.

[0081] Furthermore, during the period from the start of compressed air injection in the first main nozzle N1 to the point where its flow rate reaches the stable flow rate, if the crank angle θ reaches 80° (the second injection start time), the weft insertion control device 40 starts driving the second valve device 21.

[0082] More specifically regarding this drive, if the crank angle θ reaches 80°, the weft insertion control device 40 drives the second valve device 21 to activate only the low-flow valve 23 of both the stable flow valve 22 and the low-flow valve 23, setting the operating state of the second valve device 21 to the low-flow state. Thereby, compressed air is supplied to the second main nozzle 20 via the low-flow valve 23 in the second valve device 21. Simultaneously, compressed air begins to be injected from the second main nozzle 20.

[0083] However, the supply of compressed air from the second valve device 21 (the injection of compressed air from the second main nozzle 20) is the same as that from the first main nozzle N1 side, starting with a slight time delay relative to the start time of the second injection. Furthermore, the flow rate of the compressed air supplied to the second main nozzle 20 (and injected from the second main nozzle 20) does not immediately reach the flow rate envisioned in the low-flow valve 23 as a low flow rate, but rather gradually increases towards that low flow rate.

[0084] Furthermore, if, after 10° of the initial injection period following the transition from the operating state of the second valve device 21 to the low-flow state, i.e., when the crank angle θ reaches 90°, the weft insertion control device 40 drives the stabilizing flow valve 22 in the second valve device 21 to be in the on (open) state. This causes the second valve device 21 to switch from the low-flow state to a state supplying the aforementioned stable flow. Consequently, the supply of compressed air to the second main nozzle 20 switches from supplying via the low-flow valve 23 to supplying via the aforementioned stabilizing flow valve 22. Moreover, the flow rate of compressed air supplied to the second main nozzle 20 via the stabilizing flow valve 22 also reaches the stable flow rate at the same crank angle of 100° as the timing when the stable flow rate is reached on the first main nozzle N1 side, as described above.

[0085] Thus, the supply of compressed air using the second valve device 21 is performed as follows: First, the operation of the second valve device 21 is set to a low-flow state where the rate of increase in flow is slower than the state of supplying a stable flow. After a predetermined initial injection period, the operation switches to the state of supplying a stable flow. In this way, the flow rate of the supplied compressed air initially increases more slowly than when the second valve device 21 is set to supply a stable flow, and after this slow increase, it rises in a manner corresponding to the state of supplying a stable flow until it reaches the stable flow. As a result, at the start of the second injection, the time from the start of the compressed air supply until the flow rate reaches the stable flow is longer than when the operation of the second valve device 21 is solely for supplying a stable flow.

[0086] Furthermore, as shown in Figure 6, the pressure of the compressed air ejected from the second main nozzle 20 also increases in the same manner as the aforementioned increase in flow rate. Based on this, as described above, the initial injection period is set according to the difference in crankshaft angle between the start times of the first and second injections and the crankshaft angle at which the flow rate of the compressed air supplied to the first main nozzle N1 (ejected from the first main nozzle N1) reaches the stable flow rate. Therefore, the pressure of the compressed air ejected from the second main nozzle 20 does not precede the increase in pressure on the first main nozzle N1 side, and reaches a pressure corresponding to the stable flow rate (the same pressure as the compressed air ejected from the first main nozzle N1) at the moment the flow rate reaches the stable flow rate. Therefore, the pressure of the compressed air ejected from the second main nozzle 20 does not exceed the pressure of the compressed air ejected from the first main nozzle N1, thus suppressing the disruption of the weft yarn posture.

[0087] Furthermore, during the process of increasing the flow rate of compressed air injected from the first main nozzle N1 and the second main nozzle 20 as described above, if the crank angle θ reaches 90° (the third injection start time), the weft insertion control device 40 also drives the third valve device 31 to the on state (open state), and sets the operating state of the third valve device 31 to supply the stable flow rate. In this way, compressed air is also supplied to the third main nozzle 30 via the third valve device 31 (compressed air is injected from the third main nozzle 30). Additionally, the flow rate of compressed air supplied to the third main nozzle 30 reaches the stable flow rate at a time slightly after the crank angle reaches 100°.

[0088] Moreover, after the flow rate of compressed air supplied to the first main nozzle N1, the second main nozzle 20 and the third main nozzle 30 respectively reaches the stable flow rate as described above, the injection continues at the stable flow rate until the injection ends, that is, the stable injection state.

[0089] Based on this, if the crank angle θ reaches 180°, which is the starting point for the end of injection, the weft insertion control device 40 will drive the first valve device V1, the second valve device 21, and the third valve device 31 to the off state (closed state). This stops 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.

[0090] Furthermore, even if the supply of compressed air to each main nozzle is stopped, compressed air remains in the piping connecting each valve device and the corresponding main nozzle. Moreover, regarding the pressure of the compressed air remaining in these piping sections (residual pressure), since the length of the second piping H2 (the piping on the side of the second main nozzle 20) is shorter than the length of the first piping H1 (the piping on the side of the first main nozzle N1), the residual pressure in the second piping H2 is released (becomes zero) earlier than the residual pressure in the first piping H1. Therefore, as shown in Figure 6, the time until the residual pressure in these piping sections is completely released (the time until the pressure of the compressed air ejected from each main nozzle becomes zero) is shorter on the second main nozzle 20 side (second piping H2 side) than on the first main nozzle N1 side (first piping H1 side), thus preventing damage to the weft yarn caused by the residual pressure on the second main nozzle 20 side (second piping H2).

[0091] The above describes one embodiment (hereinafter referred to as "the above embodiment") of an air-jet loom equipped with the weft insertion device of the present invention. However, the present invention is not limited to the above embodiment and can also be implemented in other embodiments (modifications).

[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 respectively provided corresponding to the plurality of first main nozzles N1. That is, the weft insertion device 3 is configured such that each group of main nozzles has two auxiliary main nozzles N2, N2. Based on this, the weft insertion device 3 is configured such that the downstream auxiliary main nozzle N2 of the two auxiliary main nozzles N2, N2 in each group is connected to the second main nozzle 20 of the second valve device 21 configured as described above. However, in the present invention, even when the weft insertion device has two auxiliary main nozzles, it is not limited to the configuration as in the above embodiment, and it can also be configured such that the upstream auxiliary main nozzle is the second main nozzle.

[0093] Furthermore, in this case, the valve device connected to the downstream auxiliary main nozzle can also be the same as the third valve device 31 in the above embodiment, and is a valve device whose operating state is only composed of the state of supplying the above-mentioned stable flow rate. Moreover, in the present invention, when each group of main nozzles has two auxiliary main nozzles, the second main nozzle (the auxiliary main nozzle connected to the second valve device including the valve for low flow rate) is not limited to one, so in addition to the upstream auxiliary main nozzle, the downstream auxiliary main nozzle can 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 a low-flow valve 23 and a stable-flow valve 22. Furthermore, the low-flow valve 23 and the stable-flow valve 22 are integrally provided relative to the second main nozzle 20. Specifically, the low-flow valve 23 is directly installed in the nozzle body 25 of the second main nozzle 20, and the stable-flow valve 22 is configured such that the nozzle body 25 also serves as part of the stable-flow valve 22. However, in this invention, the second valve device is not limited to this configuration.

[0095] For example, regarding the flow-stabilizing valve, the portion formed by the nozzle body in the above embodiment can be formed by a component separate from the nozzle body. After configuring the flow-stabilizing valve as separate from the second main nozzle (nozzle body), the flow-stabilizing valve can be directly installed on the nozzle body. Furthermore, regarding the low-flow valve, similar to the flow-stabilizing valve in the above embodiment, the portion formed by the component separate from the nozzle body as the valve housing can be omitted. After forming the nozzle body in a manner where the same portion is included in the nozzle body, the low-flow valve can be configured such that a part of the nozzle body in the second main nozzle also serves as a part of it (valve housing).

[0096] Furthermore, in cases where the low-flow valve and the second main nozzle (nozzle body) are separately configured as in the above embodiment, and / or the stable-flow valve and the second main nozzle (nozzle body) are separately configured as described above, the valve separately configured from the second main nozzle (nozzle body) is not limited to being installed directly relative to the second main nozzle as described above; it can also be installed at a position away from the second main nozzle. Moreover, in this case, the separately configured valve is connected to the nozzle body of the second main nozzle by a pipe or the like, which becomes a second piping. However, even in the case where the valve is separately configured, in the present invention, the valve is configured such that the length of the second piping is shorter than the first piping 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 composed of two solenoid valves (a valve 22 for stable flow and a valve 23 for low flow) with different operating states. However, in this invention, the second valve device is not limited to a valve device composed of two solenoid valves in this way, and may also be composed of a single valve, which is configured to adjust (change) the opening amount (degree of opening) between the valve core and the valve seat and to change the flow rate of the supplied fluid according to the degree of opening.

[0098] In this case, the valve for low flow rate is omitted, and a throttle valve is installed instead of a valve for stable flow rate. Furthermore, the throttle valve can be installed directly on the nozzle body as in the above embodiment, or it can be installed at a position separated from the nozzle body (second main nozzle) as described above. In this configuration of the second valve device, it is operated such that during the initial injection period from the start of the second injection, the supplied flow rate is set to an opening degree that represents a low flow rate (low flow rate opening), and after the initial injection period, the supplied flow rate is set to an opening degree that represents a stable flow rate (stable flow rate opening). Moreover, in this case, the operating state of the second valve device is such that the low flow rate opening state is the low flow rate state, and the stable flow rate opening state is the state of supplying the stable flow rate.

[0099] Furthermore, 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 low flow rate, in order to change its supplied flow rate, it can be provided as the above-described throttle valve instead of the solenoid valve (low flow rate valve) as in the above embodiment. Moreover, when the second valve device is configured to include a throttle valve, considering the responsiveness of the throttle valve, it is preferable to configure it such that a solenoid valve is provided upstream of the throttle valve (between the throttle valve and the compressed air supply source), and the solenoid valve is used for on / off switching.

[0100] (4) Regarding the low-flow state during the initial injection period, in the above embodiment, the low-flow valve 23 is configured to be in an open state capable of supplying the intended low-flow rate, and the low-flow valve 23 is kept in an open state throughout the entire initial injection period to achieve the low-flow state. However, in the present invention, the low-flow state during the initial injection period is not limited to being achieved by setting a single valve configured to supply such an intended low-flow rate in an open state throughout the entire initial injection period.

[0101] For example, the second valve device may also include a solenoid valve (a first low-flow valve) in addition to a solenoid valve (equivalent to the low-flow valve 23 in the above embodiment). This solenoid valve is a solenoid valve with the same structure, configured such that the intended flow rate is larger than that of the first low-flow valve and smaller than that of the stable flow rate. During the initial injection period, the two low-flow valves are switched to achieve the low-flow state.

[0102] Specifically, the initial injection period can be divided into two periods: the period from the start of the second injection (the pre-period) and the period from the end of the pre-period to the end of the initial injection period (the post-period). During the pre-period, the first low-flow valve is open (and the second low-flow valve is closed), and during the post-period, the second low-flow valve is open, thus achieving a low-flow state. Furthermore, in this case, the degree of increase in flow rate (pressure) during this low-flow state differs between the pre-period and post-period periods, even during the initial injection period (the degree of increase is greater in the post-period). Thus, the low-flow state in this invention is not limited to a constant increase in flow rate (pressure) throughout the entire initial injection period; it can also be achieved by increasing flow rate (pressure) during a variation within the initial injection period.

[0103] Furthermore, when the second valve device is configured with two low-flow valves as described above, for example, it can be configured such that two outlet flow paths are connected to the annular flow path 25c by different phases around the annular flow path 25c, and two low-flow valves are connected to each outlet flow path. Alternatively, the second valve device can be configured with three or more low-flow valves configured with different intended flow rates, so that the flow rate increase in the low-flow state varies by three or more levels. Furthermore, for cases where the low-flow state is achieved by varying the flow rate increase during the initial injection period, instead of using multiple low-flow valves as described above, a throttle valve can be used instead of the aforementioned solenoid valve, and the opening degree of this throttle valve can be varied to achieve the low-flow state.

[0104] (5) Regarding the initial injection period, in the above embodiment, the initial injection period is set after considering various conditions related to weft insertion, provided that the timing (second stable arrival time) at which the flow rate of compressed air injected from the second main nozzle 20 reaches the stable flow rate is approximately the same as the timing (first stable arrival time) at which the flow rate of compressed air injected from the first main nozzle N1 reaches the stable flow rate.

[0105] However, in this invention, the second stable arrival time is not limited to being determined in a manner approximately consistent with the first stable arrival time as in the above embodiment. It can be determined to be a time earlier than the first stable arrival time, as long as it does not cause disruption of the weft yarn posture to the extent that it adversely affects the weft insertion. Furthermore, the second stable arrival time can also be set to a time later than the first stable arrival time, as long as it is not a time when the weft yarn suffers damage to a degree considered problematic due to the traction relationship caused by the jetting from the first main nozzle. The initial jetting period is then set according to the second stable arrival time determined in this way.

[0106] Furthermore, regarding the second injection start time, which serves as the beginning of the initial injection period, in the above embodiment, this second injection start time is set to a crankshaft angle of 80°, which is 10° behind the crankshaft angle of 70° at the first injection start time. However, even if the second injection start time is set after the first injection start time, it is not limited to being set in a manner where the difference from the first injection start time is 10° in crankshaft angle; it can be set appropriately considering the aforementioned conditions. Moreover, the second injection start time is not limited to being set after the first injection start time; it can also be set before the first injection start time, as long as it does not cause disturbance to the weft yarn posture to the extent that it adversely affects weft insertion.

[0107] Furthermore, in the above embodiment, as described above, a third main nozzle 30 is provided upstream of the second main nozzle, and the third injection start time for this third main nozzle 30 (third valve device 31) is set at a crankshaft angle of 90°, which is 10° behind the crankshaft angle of 80° that serves as the second injection start time. However, the third injection start time is not limited to being set after the second injection start time; it can be the same as the second injection start time or it can be set before the second injection start time.

[0108] (6) Regarding the weft insertion device, in the above embodiment, the weft insertion device 3 is configured with two auxiliary main nozzles N2, N2 (second main nozzle 20 and third main nozzle 30) provided relative to each first main nozzle N1. However, the weft insertion device of the present invention is not limited to being configured with two auxiliary main nozzles; it may also be configured to omit the third main nozzle, which is an upstream auxiliary main nozzle, and only have a second main nozzle, which is a downstream auxiliary main nozzle. Furthermore, the weft insertion device may also be configured to have three (or more) auxiliary main nozzles. In this case, one or more of the plurality of auxiliary main nozzles may be configured as a second main nozzle.

[0109] Furthermore, the weft insertion device of the present invention is not limited to being configured to have multiple first main nozzles N1 as in the above embodiment, but may also be configured to have only one first main nozzle.

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

[0111] 1: Air-jet loom 2: Support frame 3: Weft insertion device 5: Support strip 20: Second main nozzle 21: Second valve device 22: Valves for stabilizing flow rate 22a: Valve core 22b: Valve core drive unit 22b1: Plunger 22b2: Main Body 23: Valves for low flow rates 23a: Valve core 23b: Valve core drive unit 23b1: Plunger 23b2: Main Body 23c: Valve housing 23c1: Valve seat 23c2: Storage Space 23c3: Inflow channel 23c4:Outflow path 25: Nozzle body 25a: Through hole 25b: Mainstream Road 25c: Circular flow path 25d: Import Flow Path 25e: Pipe fitting 25f: Connecting Flow Path 25g: Annular end face 25h: Export flow path 25k: Secondary flow path 26: Management Department 27: Yarn guide 28: Mounting components 30: Third main nozzle 31: Third valve device 31a: Valve core 31b: Valve core drive unit 31b1: Plunger 31b2: Main body 35: Nozzle main body part 35a: Through hole<​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

Claims

1. A weft insertion method for an air-jet loom, the air-jet loom comprising a weft insertion device, the 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, the first main nozzle being connected to a first valve device via a first pipe, and the second main nozzle being connected to a second valve device via a second pipe shorter than the first pipe, wherein in the weft insertion device, each valve device is set to an open state and compressed air is supplied to each main nozzle during the entire injection period starting from a preset injection start time; in the weft insertion method for the air-jet loom, during an initial injection period preset from the aforementioned injection start time, the operation state of the second valve device is set to a low flow state, that is, a flow rate less than that of the stable injection state, i.e., a stable flow rate.

2. The weft insertion method of the air-jet loom as described in claim 1, wherein the aforementioned weft insertion device includes a third main nozzle disposed on the upstream side of the aforementioned second main nozzle and connected to a third valve device, and the aforementioned third valve device is configured to supply the aforementioned stable flow rate throughout the aforementioned jetting period.

3. The weft insertion method of an air-jet loom as described in claim 1 or 2, wherein the aforementioned second valve device is integrally provided relative to the aforementioned second main nozzle.

4. A weft insertion device for an air-jet loom, the weft insertion device comprising 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 being connected to a first valve device via a first pipe, and the second main nozzle being connected to a second valve device via a second pipe shorter than the first pipe, wherein in the weft insertion device, each valve device is kept open and compressed air is supplied to each main nozzle during the entire jetting period starting from a preset jetting start time; wherein the second valve device is configured to switch between a state of supplying a stable flow rate (i.e., supplying a flow rate at a stable jetting state) and a state of supplying a low flow rate (i.e., supplying a flow rate less than the stable flow rate); the weft insertion device comprising: a storage device for storing an initial jetting period preset from the jetting start time; and a control device for switching the aforementioned operating state of the second valve device and setting the aforementioned operating state of the second valve device during the initial jetting period to the aforementioned low flow rate state.

5. The weft insertion device of the air-jet loom as described in claim 4, wherein 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 configured to supply the aforementioned stable flow rate throughout the entire jetting period.

6. The weft insertion device of an air-jet loom as described in claim 4 or 5, wherein the aforementioned second valve device is integrally disposed relative to the aforementioned second main nozzle.

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