EP1835057A2

EP1835057A2 - Air jet loom

Info

Publication number: EP1835057A2
Application number: EP07004284A
Authority: EP
Inventors: Kiyoshi Arie
Original assignee: Tsudakoma Industrial Co Ltd
Current assignee: Tsudakoma Corp
Priority date: 2006-03-13
Filing date: 2007-03-01
Publication date: 2007-09-19
Also published as: CN101037824B; CN101037824A; EP1835057A3; JP2007239164A

Abstract

An air jet loom (10,110) includes a weft insertion nozzle (18,118) for inserting a weft thread (14,114) through a shed by means of an airflow; a first supply channel (28,128) for supplying the weft insertion nozzle with first compressed air for weft insertion; and a second supply channel (30,130) for supplying the weft insertion nozzle with second compressed air having a pressure different from that of the first compressed air. The second supply channel has an on-off valve (42,142) which is opened substantially when the weft thread passed through the weft insertion nozzle is cut by a thread cutter (54). Apart from the above opening operation of the on-off valve, an opening operation is performed on the on-off valve such as to thread the weft thread through the weft insertion nozzle.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an air jet loom that discharges compressed air from a weft insertion nozzle to insert a weft thread through a shed formed by warp threads.

2. Description of the Related Art

In an air jet loom, as disclosed in, for example, Japanese Patent No. 2894465 , a weft insertion nozzle is used for inserting a weft thread through a shed formed by warp threads. Specifically, the weft insertion nozzle discharges compressed air that carries the weft thread into the shed for weft insertion.
Generally, when an inserted weft thread is cut by a thread cutter, the weft thread kinks. In order to prevent a kinked weft thread from falling out of the weft insertion nozzle, compressed air having a pressure lower than that of the compressed air used for weft insertion is supplied to the weft insertion nozzle substantially when the weft thread is cut by the thread cutter. In other words, a cutting blow is supplied to the weft insertion nozzle.
Furthermore, if a weft thread does fall out of the weft insertion nozzle, the loom needs to be stopped in order to re-thread the weft thread through the weft insertion nozzle. In order to facilitate this re-threading process, compressed air having an air pressure that is lower than that of the compressed air used for weft insertion is supplied to the weft insertion nozzle only at the time of a threading process.
Consequently, since the weft insertion nozzle receives the compressed air with a pressure lower than that of the compressed air used for weft insertion at the time of a threading process, the weft thread can be carried by this low-pressure air without untwining. Accordingly, the weft thread can be threaded readily and quickly through the weft insertion nozzle.
However, in the conventional air jet loom, the compressed air used for threading the weft thread through the weft insertion nozzle is guided the weft insertion nozzle through a designated duct. Since this led to a complicated duct installation, a simplified duct arrangement has been in demand.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide an air jet loom that allows for an easy threading process for threading a weft thread through a weft insertion nozzle without requiring a complicated duct arrangement.
The present invention focuses on the point that the compressed air used for a cutting blow, which is supplied to the weft insertion nozzle substantially when a weft thread is cut by the thread cutter, is not necessary at the time of a threading process, that is, when the loom is not performing a weaving operation. Therefore, the basic concept of the present invention is that the duct for transferring the compressed air used for a cutting blow serves also as a duct for transferring compressed air used for the threading process.
Specifically, an air jet loom according to the present invention includes a weft insertion nozzle for inserting a weft thread through a shed by means of an airflow; a first supply channel for supplying the weft insertion nozzle with first compressed air for weft insertion; a second supply channel for supplying the weft insertion nozzle with second compressed air having a pressure different from that of the first compressed air, the second supply channel having an on-off valve which is opened substantially when the weft thread passed through the weft insertion nozzle is cut by a thread cutter; and a controller that opens the on-off valve so as to thread the weft thread through the weft insertion nozzle. This opening operation of the on-off valve performed by the controller for threading the weft thread through the weft insertion nozzle is performed independent of the aforementioned opening operation of the on-off valve performed substantially when the weft thread is cut by the thread cutter.
In the air jet loom according to the present invention, the second supply channel receives the second compressed air having a pressure different from that of the first compressed air for weft insertion. Since the on-off valve in the second supply channel is opened substantially when the weft thread passed through the weft insertion nozzle is cut by the thread cutter, a cutting blow similar to that in the conventional art is supplied to the weft insertion nozzle. Accordingly, this ensures that a kinked weft thread is prevented from falling out of the weft insertion nozzle after the weft thread has been cut by the thread cutter.
Moreover, since the on-off valve is also opened by the controller at the time of a threading process, the compressed air traveling through the second supply channel to be discharged from the weft insertion nozzle at the time of the threading process can properly carry the weft thread to the weft insertion nozzle. Accordingly, the weft thread can be threaded readily and quickly through the weft insertion nozzle.
According to the air jet loom of the present invention, since a duct for transferring the compressed air used for a cutting blow can serve also as a duct for transferring compressed air used for the threading process, an additional duct designated for the threading process is not necessary. In addition, by simply changing the control mode of the on-off valve, the weft insertion nozzle can be supplied with compressed air that is appropriate for the threading process, whereby the weft thread can be threaded readily and quickly through the weft insertion nozzle.
Furthermore, the controller may include a manual operating device for opening the on-off valve. In this case, the opening operation of the on-off valve performed by the controller for threading the weft thread through the weft insertion nozzle is performed when the controller is receiving a control signal from the manual operating device.
Furthermore, the manual operating device may include an operating switch for outputting the control signal, a setting unit for setting an open time period of the on-off valve, and an output unit that outputs the control signal to the on-off valve when the operating switch is operated, the control signal being output for the open time period set by the setting unit. In this case, by setting the open time period of the on-off valve to a longer time period, the jet force of the compressed air for the threading process to be discharged from the weft insertion nozzle can be increased. In contrast, by setting the open time period of the on-off valve to a shorter time period, the jet force of the compressed air for the threading process to be discharged from the weft insertion nozzle can be decreased.
Accordingly, by operating the setting unit, the open time period of the on-off valve can be preliminarily set to an appropriate value, whereby the jet force of the compressed air for the threading process to be discharged from the weft insertion nozzle can be adjusted to an optimal value in accordance with the type of weft thread.
Alternatively, the setting unit may be omitted. In that case, the manual operating device may include an operating switch for outputting the control signal and an output unit that continuously outputs the control signal to the on-off valve during a period in which the operating switch is switched on for threading the weft thread through the weft insertion nozzle. Accordingly, the jet force of the compressed air to be discharged from the weft insertion nozzle for the threading process can be adjusted based on how much time the operating switch is operated. In addition, the configuration of the manual operating device is simplified.
As described above, according to the present invention, the second supply channel, that is, a duct for transferring compressed air used for a cutting blow, can serve also as a duct for transferring compressed air used for the threading process, whereby an additional duct designated for the threading process is not necessary. Accordingly, the present invention provides an air jet loom in which the threading process can be performed readily and quickly without requiring a complicated duct arrangement for the transferring of compressed air or without leading to an increase in cost of the loom as a result of such a complicated duct arrangement.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic diagram illustrating a weft insertion apparatus included in an air jet loom according to a first embodiment of the present invention;
Fig. 2 is a block diagram of an illustrative example of a manual operating device according to the present invention shown in Fig. 1;
Fig. 3 is a block diagram similar to Fig. 2, which shows another illustrative example of the manual operating device according to the present invention; and
Fig. 4 is a schematic diagram similar to Fig. 1, which shows a weft insertion apparatus included in an air jet loom according to a second embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be described with reference to the drawings.

First Embodiment

Referring to Fig. 1, an air jet loom 10 according to the present invention includes a shedding apparatus (not shown) that is actuated synchronously with a rotation of a main shaft 12 of the air jet loom 10, a reed 16 that rocks in conjunction with the main shaft 12 to beat a weft thread 14 inserted in a shed formed by warp threads in response to the actuation of the shedding apparatus against a cloth fell, and a weft insertion apparatus 20 having a weft insertion nozzle 18 which is integrally supported by the reed 16. The reed 16 has a conventionally known air guide groove (not shown) that extends from one end of the reed 16 to the other end in the longitudinal direction thereof. The weft insertion nozzle 18 has an outlet 18a that is oriented towards the air guide groove.
The weft insertion apparatus 20 includes a pneumatic source 22 constituted by, for example, an air pump for generating compressed air, a first supply channel 28 for guiding the compressed air from the pneumatic source 22 to the weft insertion nozzle 18 by allowing the compressed air to travel through a connector 26 connected to the weft insertion nozzle 18 by means of a connecting tube 24, and second and third supply channels 30, 32 that are arranged in parallel with the first supply channel 28.
The first supply channel 28, which serves as a duct for weft insertion, has a regulator 34 for setting the pressure of the compressed air from the pneumatic source 22 to an appropriate pressure for weft insertion, a tank 36 which withholds the compressed air, whose pressure has been adjusted by the regulator 34, so as to supply the compressed air stably to the weft insertion nozzle 18, and a first on-off valve 38 that blocks off the first supply channel 28 but opens the first supply channel 28 upon receiving a control signal. The regulator 34, the tank 36, and the first on-off valve 38 are arranged in that order from the pneumatic source 22 towards the connector 26.
The second and third supply channels 30, 32 diverge from an intermediate point of the first supply channel 28 extending from the pneumatic source 22, such as to bypass the regulator 34, the tank 36, and the first on-off valve 38 and then join the first supply channel 28 again to connect to the weft insertion nozzle 18. Thus, the second and third supply channels 30, 32 each supply the weft insertion nozzle 18 with compressed air having a pressure different from that of the compressed air supplied by the first supply channel 28.
The second supply channel 30, which serves as a duct for a cutting blow, has a regulator 40 for reducing the pressure of the compressed air from the pneumatic source 22 and a second on-off valve 42 that blocks off the second supply channel 30 but opens the second supply channel 30 upon receiving a control signal. The regulator 40 and the second on-off valve 42 are arranged in that order from the upstream side of the second supply channel 30 towards the downstream side thereof that is connected to the connector 26. Moreover, the second on-off valve 42 and the connector 26 have a check valve 44 interposed therebetween for preventing a backflow of the compressed air.
For example, each of the on-off valves 38, 42 may be a conventionally known solenoid valve which opens when a solenoid coil thereof is supplied with electricity upon receiving a control signal.
The regulator 40 in the second supply channel 30 sets the pressure of the compressed air from the pneumatic source 22 to a value lower than that of the pressure set by the regulator 34 in the first supply channel 28 so that the pressure set by the regulator 40 is suitable for the cutting blow and for threading the weft thread 14 through the weft insertion nozzle 18. Consequently, setting the air pressure in the second supply channel 30 lower than the pressure of the compressed air supplied to the weft insertion nozzle 18 through the first supply channel 28 for weft insertion avoids an untwining effect on the weft thread 14 and thus prevents the weft thread 14 from untwining, whereby the threading process can be implemented readily.
The third supply channel 32, which serves as a duct for constant air supply, has a regulator 46 for reducing the pressure of the compressed air from the pneumatic source 22 and a check valve 48 for preventing a backflow of the compressed air. The regulator 46 and the check valve 48 are arranged in that order from the upstream side of the third supply channel 32 towards the downstream side thereof that is connected to the connector 26. The regulator 46 sets the pressure of the compressed air from the pneumatic source 22 to a value even lower than that of the pressure set by the regulator 40 in the second supply channel 30.
Unlike the first and the second supply channels 28, 30, the third supply channel 32 is not provided with an on-off valve. Accordingly, as long as the air jet loom 10 is turned on and the pneumatic source 22 is in operation, compressed air of a pressure lower than the pressures set by the regulators 40, 46 is constantly supplied to the weft insertion nozzle 18 through the connecting tube 24, regardless of whether the air jet loom 10 is performing or not performing a weaving operation.
As is conventionally known, even while the air jet loom 10 is in a non-weaving state, this low-pressure compressed air constantly supplied to the weft insertion nozzle 18 avoids untwining of the weft thread 14 supplied to the weft insertion nozzle 18 from a weft measuring/retaining device (not shown) and threaded through the weft insertion nozzle 18. In addition, this low-pressure compressed air prevents the leading end of the weft thread 14 extending through the weft insertion nozzle 18 from deviating from the traveling path of the weft thread 14 so as to ensure that the weft thread 14 is properly maintained within its traveling path.
The weft insertion apparatus 20 includes a control circuit 52 which opens the on-off valves 38, 42 on the basis of rotation-angle information of the main shaft 12 received from an encoder 50 provided for the main shaft 12. Based on the rotation-angle information of the main shaft 12 received from the encoder 50, the control circuit 52 outputs a control signal S1 to the first on-off valve 38 for a predetermined time period so that the compressed air used for weft insertion is discharged from the weft insertion nozzle 18 at the time of insertion of the weft thread 14. While receiving the control signal S1, the first on-off valve 38 opens for the weft insertion. The compressed air used for weft insertion will be referred to as "weft-insertion compressed air" hereinafter.
When the weft insertion nozzle 18 receives the weft-insertion compressed air in response to the opening of the first on-off valve 38, the weft thread 14, which had been maintained in the proper orientation within the weft insertion nozzle 18 by the low-pressure compressed air constantly supplied to the weft insertion nozzle 18 through the third supply channel 32, is carried by the weft-insertion compressed air so as to be discharged outward from the outlet 18a of the weft insertion nozzle 18. In this case, the weft thread 14 is carried by the weft-insertion compressed air without losing its proper orientation. Accordingly, the weft thread 14 travels along the air guide groove of the reed 16 so as to be guided properly through the shed towards the side opposite to the thread-feeding side of the woven cloth.
Subsequently, the weft thread 14 inserted through the shed is beaten against the cloth fell by the reed 16. Then, a thread cutter 54 which operates in response to a control signal S2 from the control circuit 52 cuts off the weft thread 14 from the weft insertion nozzle 18 at a section thereof that protrudes from the weft insertion nozzle 18 near the thread-feeding side. When the weft thread 14 is cut by the thread cutter 54, the control circuit 52 outputs a control signal S3 to the second on-off valve 42 for a predetermined time period.
While receiving the control signal S3, the second on-off valve 42 opens the second supply channel 30. In response to this opening of the second on-off valve 42, the compressed air used for a cutting blow is supplied to the weft insertion nozzle 18 through the second supply channel 30. This compressed air used for a cutting blow will be referred to as "cutting-blow compressed air" hereinafter. As is conventionally known, the output timing and output time period of the control signal S3 are set such as to include the cutting timing of the weft thread 14 and a period immediately following the cutting timing. In other words, the output timing and output time period are set to an extent that the cut weft thread 14 does not fall out of the weft insertion nozzle 18 due to the kink in the weft thread 14 caused as a result of the cutting thereof. For example, this period is set such that the cutting-blow compressed air is supplied to the weft insertion nozzle 18 from a point just prior to the cutting timing of the weft thread 14 to a point immediately after the cutting timing. Supplying the cutting-blow compressed air to the weft insertion nozzle 18 ensures that the kinked weft thread 14 is prevented from falling out of the weft insertion nozzle 18 after the weft thread 14 has been cut by the thread cutter 54.
When the air jet loom 10 is in the course of a weaving operation, if the weft thread 14 from the measuring/retaining device is accidentally cut off and falls out of the weft insertion nozzle 18, the weaving operation of the air jet loom 10 needs to be stopped in order to re-thread the weft thread 14 from the measuring/retaining device through the weft insertion nozzle 18. In order to facilitate this process for threading the weft thread 14 through the weft insertion nozzle 18, the weft insertion apparatus 20 is provided with a controller 56 equipped with a manual operating device 56a for opening the second on-off valve 42 in the second supply channel 30.
When the manual operating device 56a is operated to implement the threading process on the weft insertion nozzle 18, the manual operating device 56a outputs a control signal S4, which is different from the control signal S3 from the control circuit 52 for opening the second on-off valve 42, to the second on-off valve 42. Upon receiving the control signal S4, the second on-off valve 42 opens so as to set the second supply channel 30 in an opened state.
Referring to Fig. 2, the manual operating device 56a includes an operating switch 58, an output unit 60 which has an output cutoff circuit 60a and is capable of receiving an operation signal S5 from the operating switch 58, and a setting unit 62 for setting an output time period T for outputting the control signal S4 from the output unit 60, namely, an open time period of the second on-off valve 42. The operating switch 58 may be, for example, an electric switch, such as a touch switch on an operation panel (not shown) included in the manual operating device 56a, a pushbutton switch (see Fig. 3) provided in a housing (not shown) of the manual operating device 56a, a slide switch, or a rotary switch.
When the output cutoff circuit 60a in the output unit 60 is receiving a control signal S6 from the control circuit 52, which indicates that the air jet loom 10 is performing a weaving operation, the output cutoff circuit 60a cuts off the output of the output unit 60 for the control signal S4. In contrast, when the output cutoff circuit 60a is not receiving the control signal S6, the output cutoff circuit 60a permits the output unit 60 to output the control signal S4.
When the output unit 60 receives the operation signal S5 from the operating switch 58, the setting unit 62 can digitally or analogically change the duration of the output of the control signal S4 from the output unit 60 to the second on-off valve 42 in units of, for example, 0.1 seconds between one second to several seconds. By operating the setting unit 62, the output time period (i.e. the open time period) T can be set in the output unit 60 so that the output time period T can be preliminarily adjusted in accordance with the type of weft thread 14 to be threaded through the weft insertion nozzle 18, or more specifically, the strength of the weft thread 14. Furthermore, the output time period T may be set preliminarily for each type of weft thread 14 so that the output time period T can be determined simply by selecting the type of weft thread 14.
In a case where the strength and the rigidity of the weft thread 14 are relatively high, the output time period T may be set to a maximum value of, for example, two seconds in the setting unit 62. Thus, when the operating switch 58 is operated, the second on-off valve 42 opens so that compressed air with a pressure slightly lower than that of the cutting-blow compressed air, for example, can be discharged from the weft insertion nozzle 18 as compressed air used for threading the weft thread 14 through the weft insertion nozzle 18. This compressed air used for threading will be referred to as "threading compressed air" hereinafter.
On the other hand, in a case where the strength of the weft thread 14 is relatively low, the output time period T may be set to a minimum value of, for example, one second in the setting unit 62. Thus, when the operating switch 58 is operated, the second on-off valve 42 opens so that compressed air with a pressure slightly higher than that of the constantly-supplied compressed air, for example, can be discharged from the weft insertion nozzle 18 as the threading compressed air.
Accordingly, since the output time period T of the control signal S4 to be output to the second on-off valve 42 can be set preliminarily in the setting unit 62, the pressure of the threading compressed air, which is to be discharged from the weft insertion nozzle 18, can be appropriately adjusted in accordance with the property of the weft thread 14 to be threaded through the weft insertion nozzle 18, or in other words, the type of weft thread 14.
Consequently, when the threading compressed air is supplied to the weft insertion nozzle 18 in a state where the leading end of the weft thread 14 is inserted in an insertion hole of the weft insertion nozzle 18, the airflow carries the weft thread 14 outward from the outlet 18a of the weft insertion nozzle 18 without causing the weft thread to untwine. Accordingly, the weft thread 14 can be threaded readily and quickly through the weft insertion nozzle 18.
The output cutoff circuit 60a in the output unit 60 cuts off the output from the output unit 60 when the air jet loom 10 is performing a weaving operation. Therefore, even if the operating switch 58 is accidentally operated in the course of weaving, the control signal S4 is prevented from being output to the second on-off valve 42. This ensures that undesired threading compressed air is prevented from being supplied to the weft insertion nozzle 18 when the air jet loom 10 is performing a weaving operation. Accordingly, this prevents the quality of the woven cloth from deteriorating due to damages in the weft thread 14 resulting from such undesired threading compressed air being supplied to the weft insertion nozzle 18.
Alternatively, the manual operating device 56a may be incorporated in the control circuit 52. In that case, the control signal S4 to be sent to the second on-off valve 42 in response to the operation of the manual operating device 56a is output from the control circuit 52.
As described above, in the air jet loom 10 according to the present invention, the threading compressed air for threading the weft thread 14 through the weft insertion nozzle 18 is supplied to the weft insertion nozzle 18 through the second supply channel 30, which is used also for the cutting-blow compressed air, by operating the operating switch 58 of the manual operating device 56a.
Accordingly, the threading compressed air can be supplied to the weft insertion nozzle 18 without having to set a designated supply channel for threading, whereby the weft thread 14 can be threaded readily and quickly through the weft insertion nozzle 18.
Furthermore, by implementing the setting process using the setting unit 62 in the manual operating device 56a, the threading compressed air having an appropriate pressure in accordance with the type of weft thread 14 can be discharged from the weft insertion nozzle 18, regardless of how long the operating switch 58 is operated. Accordingly, the weft thread 14 can be properly and readily threaded through the weft insertion nozzle 18 without being damaged or untwined.
Referring to Fig. 3, the setting unit 62 may alternatively be omitted from the manual operating device 56a. Specifically, the manual operating device 56a may be constituted by the operating switch 58 supported by a housing (not shown), and a power source 64 connected to the operating switch 58 within the housing. In this case, the control signal S4 can be supplied to the second on-off valve 42 during a time period in which the operating switch 58 is switched on. Accordingly, this eliminates the need for the setting unit 62 and thus simplifies the configuration of the manual operating device 56a.

Second Embodiment

An air jet loom 110 shown in Fig. 4 includes a weft insertion apparatus 120 that can correspond to a plurality of weft threads of multiple colors, specifically, two weft threads 14, 114 of two colors in this embodiment. The weft insertion apparatus 120 shown in Fig. 4 includes a weft insertion nozzle 18 which is the same as that included in the weft insertion apparatus 20 in Fig. 1, and first, second, and third supply channels 28, 30, 32 in connection with the weft insertion nozzle 18. These components included in the weft insertion apparatus 120 are given the same reference numerals as those shown in Fig. 1.
Moreover, the weft insertion apparatus 120 also includes a weft insertion nozzle 118 which guides a weft thread 114, which is different from the weft thread 14 threaded through the weft insertion nozzle 18, towards the air guide groove of the reed 16. In addition, the weft insertion apparatus 120 has first to third supply channels 128, 130, 132 in connection with the weft insertion nozzle 118, which respectively diverge from the corresponding first to third supply channels 28, 30, 32.
The first supply channel 128 has an on-off valve 138 and a connector 126 which respectively correspond to the on-off valve 38 and the connector 26 in the first supply channel 28. Furthermore, the second supply channel 130 has an on-off valve 142 and a check valve 144 which respectively correspond to the on-off valve 42 and the check valve 44 in the second supply channel 30. Moreover, the third supply channel 132 has a check valve 148 which corresponds to the check valve 48 in the third supply channel 32.
The control circuit 52 alternately outputs the control signal S1 to the on-off valves 38, 138 in the respective first supply channels 28, 128, and alternately outputs the control signal S3 to the on-off valves 42, 142 in the respective second supply channels 30, 130. Consequently, as is conventionally known, the weft threads 14 and 114 are alternately supplied from the respective weft insertion nozzles 18, 118 towards the shed in accordance with the rotation angle of the main shaft 12. The weft threads 14, 114 are then cut by the thread cutter 54 which operates in response to the control signal S2 from the control circuit 52.
In this case, when the thread cutter 54 cuts the weft threads 14, 114, the corresponding on-off valves 42, 142 open in response to the control signal S3, whereby appropriate cutting-blow compressed air is supplied to the weft insertion nozzles 18, 118. Furthermore, the weft insertion nozzles 18, 118 are constantly supplied with low-pressure compressed air through the third supply channels 32, 132. Due to this low-pressure compressed air, the weft threads 14, 114 are properly maintained within the corresponding weft insertion nozzles 18, 118.
In the weft insertion apparatus 120 having the plurality of weft insertion nozzles 18, 118 as described above, by operating the setting unit 62 in the manual operating device 56a in the same manner as in the first embodiment, the output time periods T for outputting the control signal S4 to the second on-off valves 42, 142 can be set individually through the manual operating device 56a. Thus, appropriate threading compressed air can be supplied to the weft insertion nozzles 18, 118 in accordance with the types of weft threads 14, 114.
Accordingly, the open time periods of the on-off valves 42, 142 change in accordance with the control signal S4 output to the on-off valves 42, 142 from the manual operating device 56a. Therefore, depending on the type or property of the weft threads 14, 114 to be threaded through the respective weft insertion nozzles 18, 118, the threading compressed air can be discharged with an optimal jet force from the weft insertion nozzles 18, 118.
If the weft threads 14, 114 used have the same strength, the single control signal S4 from the setting unit 62 of the manual operating device 56a may be output dividedly to the on-off valves 42, 142. In that case, it is not necessary to provide an operating switch 58 for each of the nozzles. Instead, only a single operating switch 58 is required, and by operating that operating switch 58, the threading compressed air can be discharged from both weft insertion nozzles 18, 118 with the same jet force.
Furthermore, in the weft insertion apparatus 120, the manual operating device 56a may be provided with the operating switch 58 shown in Fig. 3. In that case, the manual operating device 56a has a plurality of the operating switches 58 provided independently in accordance with the number of the weft insertion nozzles 18, 118. As an alternative to the above case, the plurality of operating switches 58 may be operated in conjunction with each other.
Furthermore, in the weft insertion apparatus 120 that can correspond to multiple colors as shown in Fig. 4, the first supply channels 28, 128 intended for weft insertion and connected to the weft insertion nozzles 18, 118 share a common regulator 34. Alternatively, in a case where the weft insertion apparatus 120 corresponds to four colors, a common regulator may be used for each pair of weft insertion nozzles 18, 118.
The second on-off valves 42, 142 in the respective second supply channels 30, 130 may be opened for the threading process in conjunction with the pressing of a weaving stop button of the loom 110 or the pressing of a release button for a stopper pin of the weft measuring/retaining device. In that case, the second on-off valves 42, 142 open with a predetermined time lag after the weaving stop button or the release button has been operated. Furthermore, the operating switch 58 may operate in conjunction with the release button or may serve also as the release button. In that case, the stopper pin can be released by operating the operating switch 58.
It is not specifically described in the above embodiment how the loom operates in response to the pressing of the operating switch 58 when the second on-off valves 42, 142 are in the process of being opened for the threading process of the weft thread 14, 114. When the operating switch 58 is operated, the control signal S4 is output to the second on-off valves 42, 142, and if the threading process is completed while the second on-off valves 42, 142 are in the process of being opened, the operating switch 58 may be operated again to stop the output of the control signal S4. Thus, the second on-off valves 42, 142 close, thereby stopping the discharge from the weft insertion nozzles 18, 118.
Furthermore, in the above embodiment, the second and third supply channels 30, 32 bypass the regulator 34, the tank 36, and the first on-off valve 38 included in the first supply channel 28 extending from the pneumatic source 22 so as to connect to the weft insertion nozzle 18. Alternatively, for example, by providing each of the weft insertion nozzles 18, 118 with two or more air inlets, the second and third supply channels 30, 32 may be made independent of the first supply channel 28. This applies similarly to a weft insertion apparatus that can correspond to multiple colors.
Although the first supply channel 28, the regulator 34, and the tank 36, which are intended for weft insertion, in the configuration shown in Fig. 4 are mutually shared by the plurality of weft insertion nozzles 18, 118, these components are generally provided for each of the weft insertion nozzles.
The technical scope of the present invention is not limited to the above embodiments, and modifications are permissible without departing from the scope of the claimed invention.

Claims

An air jet loom (10, 110) that discharges compressed air from a weft insertion nozzle (18, 118) to insert a weft thread (14, 114) through a shed formed by warp threads, the air jet loom (10, 110) comprising:
the weft insertion nozzle (18, 118) for inserting the weft thread (14, 114) through the shed by means of an airflow;

a first supply channel (28, 128) for supplying the weft insertion nozzle (18, 118) with first compressed air for weft insertion;

a second supply channel (30, 130) for supplying the weft insertion nozzle (18, 118) with second compressed air having a pressure different from that of the first compressed air, the second supply channel (30, 130) having an on-off valve (42, 142) which is opened substantially when the weft thread (14, 114) passed through the weft insertion nozzle (18, 118) is cut by a thread cutter (54); and

a controller (56) that opens the on-off valve (42, 142) so as to thread the weft thread (14, 114) through the weft insertion nozzle (18, 118), wherein the opening operation of the on-off valve (42, 142) performed by the controller (56) for threading the weft thread (14, 114) through the weft insertion nozzle (18, 118) is performed independent of the opening operation of the on-off valve (42, 142) performed substantially when the weft thread (14, 114) is cut by the thread cutter (54).
The air jet loom (10, 110) according to Claim 1, wherein the controller (56) includes a manual operating device (56a) for opening the on-off valve (42, 142), and wherein the opening operation of the on-off valve (42, 142) performed by the controller (56) for threading the weft thread (14, 114) through the weft insertion nozzle (18, 118) is performed when the controller (56) is receiving a control signal (S4) from the manual operating device (56a).
The air jet loom (10, 110) according to Claim 2, wherein the manual operating device (56a) includes an operating switch (58) for outputting the control signal (S4), a setting unit (62) for setting an open time period of the on-off valve (42, 142), and an output unit (60) that outputs the control signal (S4) to the on-off valve (42, 142) when the operating switch (58) is operated, the control signal (S4) being output for the open time period set by the setting unit (62).
The air jet loom (10, 110) according to Claim 3, wherein the manual operating device (56a) includes an operating switch (58) for outputting the control signal (S4) and an output unit (64) that continuously outputs the control signal (S4) to the on-off valve (42, 142) during a period in which the operating switch (58) is switched on for threading the weft thread (14, 114) through the weft insertion nozzle (18, 118).