Patent Description:
A weft insertion device for an air jet loom is disclosed, for example, in PTL <NUM>. In the weft insertion device disclosed in PTL <NUM>, a plurality of sub-nozzles for carrying a weft that is ejected from a main nozzle toward a warp shed is arranged in the width direction of the loom. The weft insertion device includes a plurality of supply devices configured to supply air from a source to the sub-nozzles. In the weft insertion device, a predetermined number of the sub-nozzles that are adjacent to one another are grouped together, and each group of the sub-nozzles is connected to a corresponding one of the supply devices. PTL <NUM> discloses a flow distributor for a fluid circuit that is especially applicable for use in a shuttleless loom with pneumatic insertion of the weft and comprises a body of revolution, produced from two parts assembled coaxially and forming therebetween an annular inner chamber defined by a conical wall and by a frusto-conical wall. The annular chamber connects a tubular mouthpiece for the inlet of fluid disposed on the central axis body with a plurality of outlet holes provided concentrically and at regular angular intervals around the central axis and able to receive screw-threaded couplings. This flow distributor is especially used for supplying compressed air to groups of relay nozzles on a shuttleless loom.

Each of the supply devices includes: one solenoid valve; and a distributor configured to distribute, to the sub-nozzles, the air supplied from the source via the solenoid valve. Formed in the distributor are: a main channel having an inlet end that is joined to the solenoid valve and an outlet end that is closed by an end wall; and a plurality of branch channels each having an inlet end that communicates with the main channel in the vicinity of its outlet end and an outlet end that is connectable to a corresponding one of the sub-nozzles. The air that has been supplied from the source to the supply devices is sent to the main channels via the solenoid valves and is then supplied to the sub-nozzles through the branch channels.

In the supply devices of the weft insertion device disclosed in PTL <NUM>, the inlet end of each of the branch channels is joined to a surrounding wall of the main channel in the vicinity of its outlet end. Air supplied from the solenoid valve to the main channel flows along an axis of the main channel (that is, along the surrounding wall of the main channel) toward the branch channels. Therefore, in the configuration disclosed in PTL <NUM> (hereinafter, referred to as a "conventional configuration"), the air that has reached before the inlet ends of the branch channels heads for the outlet end of the main channel for the most part passing by the inlet ends of the branch channels. The air that has reached the outlet end of the main channel then bumps against the end wall toward the inlet ends of the branch channels and, colliding with the air supplied from the solenoid valve, flows into the branch channels.

In the conventional configuration, the air flows more to the outlet end of the main channel (and bumps against the end wall) than to the inlet ends of the branch channels. Consequently, collision between the air that is supplied from the solenoid valve and the air that has bumped against the end wall causes turbulence, which can inflict ill effects on weft insertion.

In addition, the turbulence can prolong time for jet pressure in the sub-nozzles to rise to a desired pressure. Although an earlier start of supplying air (earlier opening of the solenoid valve) may ensure that the jet pressure has risen to the desired pressure by arrival of a weft to the sub-nozzles, a longer-term jet of air consumes a larger amount of air.

An object of the present invention is to provide a configuration of a weft insertion device that can reduce turbulence in air flowing into the branch channels to reduce ill effects of the turbulence on weft insertion and the amount of air consumed.

In order to achieve the object, in a weft insertion device of the present invention, the inlet end of each of the branch channels communicates with the main channel such that at least part of the inlet end of each of the branch channels covers the end wall of the main channel.

The branch channels may be formed such that, as viewed from the weft insertion direction, an angle between an axis (which passes through the center of the channel and extends along the channel) of the main channel and an axis of one of the branch channels (first branch channel) that is connectable to the one of the sub-nozzles that is on an upstream side is greater than or equal to an angle between the axis of the main channel and an axis of one of the branch channels (second branch channel) that is connectable to one of the sub-nozzles that is on a downstream side.

The branch channels are formed such that their inlet ends overlap with each other. Moreover, each of the branch channels may be formed such that, as viewed from the length direction of the main channel, the center of its inlet end is within the main channel.

In the weft insertion device of the present invention, the inlet end of each of the branch channels communicates with the main channel such that at least part of the inlet end of each of the branch channels covers the end wall of the main channel. Compared to the conventional configuration, air that has been introduced into the main channel toward each of the branch channels flows more directly into each of the branch channels. Since the air bumps less against the end wall of the main channel compared to the conventional configuration, turbulence in the air flowing into the branch channels can be reduced in the main channel.

The configuration of the weft insertion device of the present invention reduces the turbulence in the air flowing into each of the branch channels, thereby reducing ill effects of the turbulence on weft insertion. In addition, reduction in turbulence shortens the time for the jet pressure to rise to a desired pressure. Since jet duration in the sub-nozzles can be shortened, the amount of air consumed can be reduced.

As for a configuration of the branch channels in the weft insertion device of the present invention, that is, angles between the axis of the main channel and the axis of each of the branch channels as viewed from the weft insertion direction, if the branch channels are formed such that the angle between the axis of the main channel and the axis of the first branch channel is greater than that between the axis of the main channel and the axis of the second branch channel, hydrodynamic resistance to the air flowing through each of the branch channels is lower in the first branch channel than in the second branch channel. In this case, the air flows more smoothly into the first branch channel than into the second branch channel, and the time for the jet pressure to rise to the desired pressure is shorter in one of the sub-nozzles that is on the upstream side than in one of the sub-nozzles that is on the downstream side. Since the jet pressure in the sub-nozzle on the upstream side, by which a weft passes earlier than the weft passes by the sub-nozzle on the downstream side, rises earlier than in the sub-nozzle on the downstream side automatically, the jet duration of the sub-nozzles can be further shortened and thus the amount of air consumed can be further reduced.

If the branch channels in the weft insertion device of the present invention are formed such that their inlet ends overlap with each other, air can be jetted from each of the sub-nozzles more appropriately for the configuration of the branch channels than if the branch channels are formed such that their inlet ends are separate from each other.

If the air flows into the branch channels inappropriately for the configuration, properties, such as a start-up pressure, of the air jetted from the sub-nozzles are expected to be inappropriate for the configuration. If the branch channels are formed such that they are separate from each other, flow of the air may be inappropriate for the configuration at least when the air starts to flow into the branch channels from the main channel. In this case, a rise of the jet pressure may be delayed, and thus the air may be jetted from the sub-nozzles inappropriately for the configuration.

In contrast, if the branch channels are formed such that their inlet ends overlap with each other, both of the branch channels communicate with the main channel through the overlap. Therefore, the air that has been supplied from the solenoid valve to the main channel first flows into the overlap, which is part of the branch channels, and then flows downstream. Since the flow when the air starts to flow into the branch channels is more appropriate for the configuration than if the branch channels are formed such that they are separate from each other, the air can be jetted from each of the sub-nozzles appropriately for the configuration.

Moreover, if each of the branch channels is formed such that, as viewed from the length direction of the main channel, the center of its inlet end is within the main channel, it communicates with the main channel at a position closer to the end wall than the surrounding wall. Since the air flows more smoothly into each of the branch channels than if each of the branch channels is formed such that the center of its inlet end is out of the main channel, the jet pressure in each of the sub-nozzles rises faster and thus the amount of air consumed can be further reduced.

In the following, an embodiment of a weft insertion device for an air jet loom (hereinafter, simply referred to as a "loom") of the present invention will be described with reference to <FIG>.

The loom <NUM> includes a beating device <NUM>, which is configured to drive a reed <NUM> in a swinging manner. In the beating device <NUM>, the reed <NUM> is supported on a rocking shaft <NUM> by the intermediacy of a sley <NUM> and a sley sword <NUM>. The rocking shaft <NUM> is swingably supported between loom frames. The loom frames includes: a pair of side frames <NUM> (only one of them is shown), which are provided apart from each other in the width direction (parallel to the weft insertion direction) of the loom <NUM>; and a plurality of (generally, four) beams configured to connect the side frames <NUM>, although shown is only one of them that is a front top stay <NUM>, which is provided in an upper end part of the side frames <NUM> and closer to the winding side of a woven fabric W than a cloth fell.

The loom further <NUM> includes a weft insertion device <NUM> for inserting a weft into a warp shed. The weft insertion device <NUM> includes: a main nozzle MN; and a plurality of sub-nozzles SN. The main nozzle MN and the sub-nozzles SN are attached to the sley <NUM>. The sub-nozzles SN are arranged at predetermined intervals in the width direction. During a weft insertion process of weaving, each of the sub-nozzles SN is supplied with air for a predetermined period of time, and the air is jetted from each of the sub-nozzles SN.

The loom <NUM> further includes an air tank configured to store the air. In the present embodiment, the front top stay <NUM> is configured as the air tank. In this regard, the front top stay <NUM> has a prismatic shape and is hollow inside. The front top stay <NUM> (hereinafter, also referred to as the air tank) has an inlet 13a, through which air with a pressure regulated by a regulator or the like is supplied from a source (not shown).

The weft insertion device <NUM> further includes a plurality of supply devices <NUM>. Every adj acent two of the sub-nozzles SN are grouped together and are provided with a corresponding one of the supply devices <NUM>. In the present embodiment, the supply devices <NUM> are fixed to a sidewall of the air tank (front top stay) <NUM> with screws <NUM>.

Each of the supply devices <NUM> includes: a solenoid valve <NUM>, which is configured to let the air supplied from the source through or shut off the air switchably; and a distributor <NUM>, which is configured to distribute, to the two sub-nozzles SN, the air supplied from the air tank <NUM> via the solenoid valve <NUM>. Each of the solenoid valves <NUM> is controlled, for example, by a controller of the loom <NUM>. The distributor <NUM> includes a supply channel <NUM>, which is configured to convey the air supplied from the air tank <NUM> to the solenoid valve <NUM>. The supply channel <NUM> is formed in the distributor <NUM> such that, when the supply device <NUM> is attached to the air tank <NUM>, an inlet end of the supply channel <NUM> is joined to an outlet 13b, which is formed in the air tank <NUM>. An outlet end of the supply channel <NUM> is joined to an inlet of the solenoid valve <NUM>.

The distributor <NUM> further includes: a main channel <NUM>, which has an inlet end that is joined to an outlet of the solenoid valve <NUM> and an outlet end that is partially closed; a pair of branch channels <NUM>, each of which is formed such that it is joined to the main channel <NUM>. Therefore, in the supply device <NUM>, the air that has been introduced from the air tank <NUM> to the supply channel <NUM> of the distributor <NUM> is introduced into the main channel <NUM> and the branch channels <NUM> via the solenoid valve <NUM>. The solenoid valve <NUM> and the distributor <NUM> are integrated. The outlet end of the main channel <NUM> of the distributor <NUM> is partially closed by an end wall 18a, which is perpendicular to the length direction of the main channel <NUM>.

The supply device <NUM> is connectable to the two sub-nozzles SN by tubes <NUM> with each of the tubes <NUM> connected to a corresponding one of the branch channels <NUM> by a joint <NUM>. Therefore, the air that has been introduced into the branch channels <NUM> is supplied to the sub-nozzles SN via the tubes <NUM>.

As described above, the supply device <NUM> of the weft insertion device <NUM> is configured to split the air that has been introduced into the distributor <NUM> from the air tank <NUM> into two in the branch channels <NUM> and to supply the air to the two sub-nozzles SN. In the present invention, the inlet end of each of the branch channels <NUM> communicates with the main channel <NUM> such that at least part of the inlet end of each of the branch channels covers the end wall 18a, which partially closes the outlet end of the main channel <NUM>. That is, at least part of the inlet end of each of the branch channels <NUM> is joined to an opening covering the end wall 18a. Specifically, in the supply device <NUM> of the present embodiment, the branch channels <NUM> are formed such that their inlet ends overlap with each other as below.

In the supply device <NUM>, the inlet end of each of the branch channels <NUM> communicates with the main channel <NUM> such that at least part of the inlet end of each of the branch channels covers the end wall 18a. As shown in <FIG>, which is drawn from the weft insertion direction, each of the branch channels <NUM> is formed such that it faces in the rear direction (direction of the locking shaft <NUM> from the air tank <NUM>) of the loom and diagonally upward. In addition, as shown in <FIG>, each of the branch
channels <NUM> is inclined to the left or the right at an angle β from an axis of the main channel <NUM> as viewed from the front-rear direction of the loom <NUM>.

Further, as shown in <FIG>, the branch channels 19a and 19b are formed such that their inlet ends overlap with each other. Therefore, each of the branch channels <NUM> communicates with the main channel <NUM> through the overlap between their inlet ends. The inlet end of each of the branch channels 19a and 19b, or the overlap communicates with the main channel <NUM> such that it covers the end wall 18a as described above. Additionally, it further covers part of a surrounding wall 18b of the main channel <NUM> (it straddles a border between the end wall 18a and the surrounding wall 18b) in the present embodiment, although it is, for the most part, within the end wall 18a. Therefore, the center of the inlet end of each of the branch channels <NUM> is not within the surrounding wall 18b but within the end wall 18a. That is, each of the branch channel <NUM> is formed such that, as viewed from the length direction of the main channel <NUM>, the center of its inlet end is within the main channel <NUM>.

In the present embodiment, on the axis of the main channel <NUM> is an intersection of: an axis of the first branch channel 19a (left branch channel in <FIG>) of the two branch channels <NUM>, which is connectable to one of the two sub-nozzles SN that is on the upstream side in the weft insertion direction; and an axis of the second branch channel 19b (right branch channel in <FIG>) of the two branch channels <NUM>, which is connectable to one of the two sub-nozzles SN that is on the downstream side in the weft insertion direction. Further, as shown in <FIG>, the branch channels 19a and 19b are formed such that, as viewed from the weft insertion direction, an angle α<NUM> between the axis of the main channel <NUM> and the axis of the first branch channel 19a is greater than an angle α<NUM> between the axis of the main channel <NUM> and the axis of the second branch channel 19b.

As described above, the inlet end of each of the branch channels <NUM> of the supply device <NUM> (distributor <NUM>) in the weft insertion device <NUM> of the present embodiment communicates with the main channel <NUM> such that it covers part of the end wall 18a for the most part. The weft insertion device <NUM>, which includes the supply device <NUM>, the air that has been introduced into the main channel <NUM> toward each of the branch channels <NUM> flows more directly into each of the branch channels <NUM> compared to the conventional configuration, in which the inlet end of each of the branch channels of the distributor communicates with the main channel such that it covers only part of the surrounding wall of the main channel. Since the air bumps less against the tip wall 18a of the main channel <NUM> compared to the conventional configuration, turbulence in the air flowing into the branch channels <NUM> can be reduced.

As a result, ill effects of the turbulence of on weft insertion can also be reduced. In addition, reduction in turbulence shortens the time for the jet pressure in each of the sub-nozzles SN to rise to a desired pressure. Since the jet duration in each of the sub-nozzles SN can be shortened, the amount of air consumed can be reduced.

In the present embodiment, as viewed from the weft insertion direction, the angle α<NUM> between the axis of the main channel <NUM> and the axis of the first branch channel 19a is greater than the angle α<NUM> between the axis of the main channel <NUM> and the axis of the second branch channel 19b. With such a configuration of the branch channels <NUM>, the hydrodynamic resistance to the air flowing through each of the branch channels <NUM> is lower in the first branch channel 19a than in the second branch channel 19b. For this reason, the air flows more smoothly into the first branch channel 19a than into the second branch channel 19b, and the time for the jet pressure to rise to the desired pressure is shorter in one of the sub-nozzles SN that is on the upstream side than in one of the sub-nozzles SN that is on the downstream side. Since the jet pressure in the sub-nozzle SN on the upstream side, by which a weft passes earlier than the weft passes by the sub-nozzle SN on the downstream side, rises earlier than in the sub-nozzle SN on the downstream side automatically, the jet duration of the sub-nozzles SN in each group can be further shortened and thus the amount of air consumed can be further reduced.

In the present embodiment, each of the branch channels 19a and 19b communicate with the main channel <NUM> through the overlap between the branch channels 19a and 19b on the main channel <NUM>. Therefore, the air that has been introduced into the main channel <NUM> first flows into the overlap, which is part of the branch channels <NUM>, and then flows downstream. Since the flow is more appropriate for the configuration than if the branch channels <NUM> are formed such that they are separate from each other at least when the air starts to flow into the branch channels <NUM>, properties, such as a start-up pressure, of the air jetted from the sub-nozzles SN are appropriate for the configuration.

In the present embodiment, the branch channels 19a and 19b are formed such that they overlap with each other as described above and, as viewed from the length direction of the main channel <NUM>, the center of the inlet end of each of them is within the main channel <NUM>. That is, each of the branch channels <NUM> communicates with the main channel <NUM> at a position closer to the end wall 18a than the surrounding wall 18b. Since the air flows more smoothly into each of the branch channels <NUM> than if the center of the inlet end of each of the branch channels <NUM> is out of the main channel <NUM>, the jet pressure in each of the sub-nozzles SN rises faster and thus the amount of air consumed can be further reduced.

Although a weft insertion device for an air jet loom of an embodiment (hereinafter, referred to as an "above embodiment") has been described above, the present invention is not limited to the above embodiment and some variants can be conceived as other embodiments.

First, although the inlet end of each of the branch channels 19a and 19b communicates with the main channel <NUM> such that it straddles the border between the end wall 18a and the surrounding wall 18b in the above embodiment, the present invention is not limited thereto: the inlet ends of the branch channels 19a and 19b may communicate with the main channel <NUM> such that one or both of them cover only part of the end wall 18a.

In addition, although each of the inlet ends of the branch channels 19a and 19b is, for the most part, within the end wall 18a in the above embodiment, the present invention is not limited thereto as long as at least part of the inlet end of each of the branch channels covers the end wall 18a. That is, the inlet end of the branch channel 19a or 19b may cover a larger part of the surrounding wall 18b and a smaller part of the end wall 18a. In this case, as viewed from the length direction of the main channel <NUM>, the center of the inlet end of the branch channel 19a or 19b is out of the main channel <NUM>. Therefore, the present invention is not limited to the above embodiment, in which each of the branch channels 19a and 19b are formed such that, as viewed from the length direction of the main channel <NUM>, the center of its inlet end is within the main channel <NUM>: the center of the inlet end of the branch channel 19a or 19b may be out of the main channel <NUM>.

Second, although the branch channels 19a and 19b are formed such that, as viewed from the weft insertion direction, the angle α<NUM> between the axis of the main channel <NUM> and the axis of the first branch channel 19a is greater than the angle α<NUM> between the axis of the main channel <NUM> and the axis of the second branch channel 19b in the above embodiment, the present invention is not limited thereto: the angle α<NUM> may be equal to the angle α<NUM>.

In addition, although the branch channels 19a and <NUM> are formed such that, as viewed from the front-rear direction of the loom <NUM>, each of them is inclined to the left or the right at the same angle β from the axis of the main channel <NUM> in the above embodiment, the present invention is not limited thereto: the angle for the first branch channel 18a and that for the second branch channel 18b may be different from each other.

Further, although the branch channels 19a and 19b are formed such that the axes of them cross, each of the axes cross the axis of the main channel <NUM>, and the intersection of the axes is on the axis in the above embodiment, the present invention is not limited thereto.

For example, even if the branch channels 19a and 19b are formed such that the axes of them cross, they may be formed such that the intersection is off the axis of the main channel <NUM>. In addition, even if they are formed such that the axes of them cross, only one of the axes and the axis of the main channel <NUM> may cross. Further, they may be formed such that the axes of them do not cross. In this case, they may be formed such that both, one, or none of the axes and the axis of the main channel <NUM> cross.

Third, although the supply devices <NUM> are directly attached to the sidewall of the front top stay <NUM> in the above embodiment, the present invention is not limited thereto.

For example, each of the supply devices <NUM> may be attached to the front top stay <NUM> by the intermediacy of a support member, such as a bracket. In this case, the outlet 13b of the front top stay <NUM> and the supply channel <NUM> of the distributor <NUM> of the supply device <NUM> are connected by a joint, a tube, or the like.

Using such a support member, positions or directions of the supply devices <NUM> in the front-rear direction can be adjusted more freely compared to the above embodiment. The supply devices <NUM> can be provided such that each of the branch channels <NUM> faces frontward, although it faces rearward in the above embodiment.

In addition, although the distributor <NUM> is configured (the branch channels <NUM> are formed in the distributor <NUM>) such that each of the branch channels <NUM> faces diagonally upward in consideration of a position or a manner of the supply device <NUM> installed, each of the branch channels <NUM> may face levelly (parallelly to the font-rear direction) or diagonally downward if the support member as described above is used. That is, when the supply device <NUM> is installed, each of the branch channels <NUM> may face in the horizontal direction or in the diagonally downward direction as long as it faces in a direction having a front-rear component, although it faces in the diagonally upward direction in the above embodiment. In addition, both of the branch channels <NUM> do not have to face in the same direction: each of them may face in a different direction as long as it faces in the diagonally upward or downward direction or in the horizontal direction.

Fourth, although the main channel <NUM> is formed such that the end wall 18a is orthogonal to the length direction of the main channel <NUM> in the above embodiment, the present invention is not limited thereto: the main channel <NUM> may be formed such that the end wall 18a has, for example, a conical shape. In this case, the end wall 18a is diagonal to the length direction of the main channel <NUM>.

Fifth, each channel (main or branch channel) of the distributor <NUM> may be formed such that its cross section has a circular, elliptical, or polygonal shape.

Claim 1:
A weft insertion device (<NUM>) for an air jet loom (<NUM>), the weft insertion device (<NUM>) comprising a plurality of supply devices (<NUM>) each including:
one solenoid valve (<NUM>); and
a distributor (<NUM>) configured to distribute, to two sub-nozzles (SN), air supplied from a source via the solenoid valve (<NUM>), wherein
the distributor (<NUM>) includes:
a main channel (<NUM>) having an inlet end that is joined to the solenoid valve (<NUM>) and an outlet end that is closed by an end wall (18a); and
a pair of branch channels (<NUM>, 19a, 19b) each having an inlet end that is joined to the outlet end of the main channel and an outlet end that is connectable to a corresponding one of the sub-nozzles (SN),
each of the branch channels (<NUM>, 19a, 19b) is formed such that, when the weft insertion device (<NUM>) is attached to the air jet loom (<NUM>), it faces in a direction having at least a component parallel to a front-rear direction of the air jet loom (<NUM>), and
the inlet end of each of the branch channels (<NUM>, 19a, 19b) communicates with the main channel (<NUM>) such that at least part of the inlet end of each of the branch channels (<NUM>, 19a, 19b) covers the end wall (18a), characterized in that
the branch channels (<NUM>, 19a, 19b) are formed such that their inlet ends overlap with each other.