Weft detection device for air jet looms

Abstract

To provide a weft detection device for an air jet loom that can improve the detection performance of the weft thread. [Solution] The air jet loom 10 comprises a reed 13 in which a plurality of reed dents 15 are arranged in a row in the weft insertion direction X, and a weft detection device 30. The weft detection device 30 comprises a weft sensor 31 and a reflective member 40. The weft sensor 31 has a light-emitting part 32a that projects light toward the reed internal passage 13b and a light-receiving part 32b that receives light, each at the sensor end 32. The weft sensor 31 is positioned with its sensor end 32 facing the reed internal passage 13b. The reflective member 40 is positioned between adjacent reed dents 15 in the weft insertion direction X. The reflective member 40 has an arc-shaped surface 45. The arc-shaped surface 45 reflects the light projected from the light-emitting part 32a toward the light-receiving part 32b. The arc-shaped surface 45 is concave in the direction away from the light-emitting part 32a when viewed from the weft insertion direction X.

Description

Technical Field

[0001] The present invention relates to a weft yarn detection device for an air jet loom.

Background Art

[0002] An air jet loom is provided with an optical weft yarn detection device to detect whether the weft yarn is properly inserted. The weft yarn detection device is installed on the reed. The light projecting part of the weft yarn detection device projects light toward the inserted weft yarn, and the light reflected by hitting the weft yarn is received by the light receiving part. In the weft yarn detection device, the light projecting part is the part constituted by a light projecting element, and the light receiving part is the part constituted by a light receiving element.

[0003] When the weft yarn reaches the projection area of the light projecting part, the light receiving part receives the reflected light from the weft yarn and converts it into an electrical signal, and the converted electrical signal is sent to the control part of the air jet loom. On the other hand, when the weft yarn does not reach the projection area of the light projecting part, the electrical signal related to the reflected light from the weft yarn is not sent from the light receiving part to the control part. In this case, the control part of the air jet loom determines that the weft insertion is defective and stops the operation of the air jet loom.

[0004] In order to improve the detection efficiency by the weft yarn detection device, the air jet loom is provided with a contrast adjusting member disclosed in, for example, Patent Document 1. The contrast adjusting member is arranged between the reed teeth adjacent to each other in the weft insertion direction. The contrast adjusting member extends longitudinally in the longitudinal direction of the reed teeth and has an inverted L shape when viewed from the weft insertion direction.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In a weft detection device, if there is a difference in the amount of reflected light from a part other than the weft, depending on the part from which the light was reflected, there is a risk that the detection performance of the weft will decrease due to this difference. [Means for solving the problem]

[0007] A weft detection device for an air jet loom to solve the above problems is a weft detection device for an air jet loom equipped with a reed having a plurality of rows of reed blades having guide recesses in the weft insertion direction, in which the weft is inserted through a passage inside the reed formed by the plurality of guide recesses by the injection of air, comprising: a weft sensor equipped with a light-emitting unit that projects light toward the passage inside the reed and a light-receiving unit that receives light, each of which is provided at the sensor end and the sensor end is positioned facing the passage inside the reed; and a reflective member positioned between adjacent reed blades in the weft insertion direction, provided at a position where light is projected from the light-emitting unit through the passage inside the reed, and having an arc-shaped surface that reflects the light projected from the light-emitting unit toward the light-receiving unit, wherein the arc-shaped surface is concave in the direction away from the light-emitting unit when viewed from the weft insertion direction.

[0008] According to this, light projected from the light-emitting part at the end of the sensor passes through the reed passage and is then reflected by the arc-shaped surface toward the light-receiving part. The light reflected by the arc-shaped surface passes through the reed passage again and is then received by the light-receiving part at the end of the sensor. For example, compared to the case where the surface of the reflective member facing the end of the sensor is made up of a flat surface, the amount of reflected light received by the light-receiving part of the weft detection device increases.

[0009] Furthermore, since the arc-shaped surface is concave in the direction away from the light-emitting part when viewed from the weft insertion direction, the diffusion of light reflected by the arc-shaped surface can be suppressed. In other words, by having an arc-shaped surface, the reflective member can reduce the difference in the amount of light received by the light-receiving part that depends on the location where the light is reflected. As a result, the weft detection device can suppress a decrease in the weft detection performance depending on the position where the weft is flying in the reed passage. Consequently, the weft detection device can improve the weft detection performance.

[0010] In the weft detection device for an air jet loom, the reed has a base end connected to the sleigh and a tip on the opposite side of the base end in the longitudinal direction, the weft sensor is fixed to the sleigh and has the light-emitting part facing the portion of the reed passage closer to the base end of the reed, the reflective member has the arc-shaped surface in the longitudinal direction of the reed closer to the tip of the reed than the guide recess, and the arc-shaped surface is preferably an arc with the light-emitting part as the center when viewed from the direction of weft insertion.

[0011] According to this, the reflective member reflects light that has passed through the portion of the reed passage closer to the tips of the reed dents. The portion of the reed passage closer to the tips of the reed dents is further from the light source compared to other parts of the reed passage. In other words, by having an arc-shaped surface near the tips of the reed dents, the reflective member can suppress the decrease in the amount of reflected light even in locations far from the light source. As a result, the weft detection device of the air jet loom can improve the detection performance of the weft in the portion of the reed passage where weft detection is relatively difficult.

[0012] Furthermore, the arc-shaped surface is an arc with its center at the light-emitting section when viewed from the weft insertion direction. This prevents the light projected from the light-emitting section from traveling along a path different from the path it took when incident on the arc-shaped surface when viewed from the weft insertion direction, after being reflected by the arc-shaped surface. Therefore, the reflective member can prevent the light projected from the light-emitting section from reaching a different location than the light-receiving section due to reflection on the arc-shaped surface. As a result, the weft detection device of the air jet loom can reduce the difference in the amount of light received by the light-receiving section, which depends on the location where the light is reflected. Consequently, the weft detection device can suppress a decrease in the detection performance of the weft even when the weft is flying through a part of the reed passage away from the light-emitting section. Therefore, the weft detection device of the air jet loom can improve the detection performance of the weft in the reed passage.

[0013] In the weft detection device of an air jet loom, the reflective member may have the arc-shaped surface on the entire surface onto which light is projected from the light-emitting unit through the reed passage. According to this, compared to the case where the reflective member has an arc-shaped surface only on a portion of the surface from which light is projected from the light-emitting unit through the reed passage, the difference in the amount of light received by the light-receiving unit, which depends on the location of light reflection, can be reduced. As a result, the weft detection device of the air jet loom can improve the weft detection performance throughout the entire reed passage.

[0014] In the weft detection device of an air jet loom, the reflective member preferably has a portion on the arc-shaped surface that is flush with the surface of the reed blade adjacent to the reflective member that forms the reed passage, and is positioned so as not to overlap with the reed passage when viewed from the direction of weft insertion.

[0015] According to this, the reflective member is positioned between the reed blades so as not to overlap with the reed passage in the weft insertion direction, while shortening the distance to the light-emitting part by having a portion that is flush with the surface forming the reed passage. In other words, the reflective member can shorten the path of light from the light-emitting part to the light-receiving part via the arc-shaped surface without interfering with the flight of the weft yarn in the reed passage. In short, the weft detection device of an air jet loom can improve the detection performance of the weft yarn in the reed passage without interfering with the insertion of the weft yarn.

[0016] In the weft detection device of an air jet loom, the reflective member is configured such that the portion of the reed blade closer to the base end than the arc-shaped surface in the longitudinal direction of the reed blade is composed of a straight surface extending in the longitudinal direction of the reed blade, and the reflective member is provided in a position adjacent to the reed blade where the surface that defines the internal passage of the reed and faces the opening direction of the guide recess and the straight surface are flush.

[0017] When the reflecting member is provided at a position away from the inside passage of the reed, the reflecting member and the adjacent reed blades form a groove communicating with the inside passage of the reed. In an air jet loom, for example, when weaving is performed using span yarn, fluff generated from the span yarn may be trapped in the groove. The weft yarn detecting device of the air jet loom can suppress fluff clogging caused by the groove by making the linear surface of the reflecting member and the surface of the reed blade adjacent to the reflecting member facing the opening direction of the guide recess flush. Thereby, the weft yarn detecting device of the air jet loom can improve the detecting performance of the weft yarn.

Effect of the Invention

[0018] According to the present invention, the detecting performance of the weft yarn can be improved.

Brief Description of the Drawings

[0019] [Figure 1] FIG. 1 is a schematic perspective view showing an air jet loom and a weft yarn detecting device. [Figure 2] FIG. 2 is an enlarged perspective view showing a reed, a vibration suppressing member, and a reflecting member. [Figure 3] FIG. 3 is a broken side view showing a reed and a weft yarn detecting device. [Figure 4] FIG. 4 is a perspective view showing a vibration suppressing member and a reflecting member. [Figure 5] FIG. 5 is a partial side view showing a weft yarn detecting device. [Figure 6] FIG. 6 is an enlarged perspective view showing a reed, a vibration suppressing member, and a reflecting member in a modified example. [Figure 7] FIG. 7 is a partial side view showing a weft yarn detecting device in a modified example.

Mode for Carrying Out the Invention

[0020] Hereinafter, an embodiment of a weft yarn detecting device of an air jet loom will be described. <Overall Image of the Air Jet Loom> As shown in Figure 1, the air jet loom 10 comprises a main nozzle 11, a plurality of sub-nozzles 12, a reed 13, a sleigh 14, and a vibration damping member 20. Each of the main nozzle 11, the plurality of sub-nozzles 12, and the reed 13 is fixed to the sleigh 14. The vibration damping member 20 is attached to the reed 13. The air jet loom 10 weaves a fabric C using weft yarn Y and warp yarn T.

[0021] The main nozzle 11 is fixed to one end of the slay 14 in the longitudinal direction. The main nozzle 11 injects the weft yarn Y along the longitudinal direction of the slay 14. In this embodiment, the weft yarn Y is a spun yarn. However, the weft yarn Y does not have to be a spun yarn.

[0022] Hereafter, the direction in which the weft thread Y flies via the main nozzle 11 will be referred to as the weft insertion direction X. In the weft insertion direction X, the direction in front of the flying weft thread Y will be referred to as "downstream," and the opposite side of the downstream direction in the weft insertion direction X will be referred to as "upstream." In other words, the weft insertion direction X is the direction from upstream to downstream. The weft insertion direction X coincides with the longitudinal direction of the slay 14. The weft thread Y flies from upstream to downstream via the main nozzle 11.

[0023] Multiple sub-nozzles 12 are arranged in a row on the slay 14 in the lath insertion direction X. The base ends of the sub-nozzles 12 are attached to the slay 14 so as to be adjustable in the lath insertion direction X. The sub-nozzles 12 are equipped with an air injection port (not shown) at their tip. The sub-nozzles 12 are configured to inject air from the air injection port. The air is supplied to the sub-nozzles 12 from a pipe 12a connected to the base end of the sub-nozzle 12.

[0024] The reed 13 comprises two holding members 13a and a plurality of reed fins 15. The two holding members 13a are columnar bodies extending in the weft insertion direction X. The plurality of reed fins 15 are held by the two holding members 13a. The reed fins 15 are long, plate-shaped. Both ends of each reed fin 15 in the longitudinal direction are connected to the holding members 13a. In other words, the reed fins 15 are connected to the holding members 13a at both ends in the longitudinal direction. That is, in the reed 13, the reed fins 15 are fixed to the holding members 13a such that their longitudinal direction is perpendicular to the weft insertion direction X. In the reed 13, the plurality of reed fins 15 are arranged in a row in the weft insertion direction X, with a constant spacing between them in the thickness direction of each reed fin 15. In other words, the air jet loom 10 is equipped with a reed 13 in which multiple rows of reeds 15 are arranged in the weft insertion direction X. The multiple reeds 15 are set on the slay 14 with their thickness direction aligned with the weft insertion direction X.

[0025] One of the two retaining members 13a is installed in a groove formed in the sleigh 14. The reed 15 is erected on the sleigh 14. Hereafter, the end of the reed 15 in the longitudinal direction that is closer to the sleigh 14 will be referred to as the base end, and the end opposite to the base end will be referred to as the tip. In other words, the reed 15 has a base end connected to the sleigh 14, and a tip on the opposite side of the base end in the longitudinal direction.

[0026] As shown in Figures 2 and 3, the reed feathers 15 have a guide recess 15a. The reed feathers 15 open in the opening direction A at the guide recess 15a. In other words, the guide recess 15a opens toward the opening direction A. The opening direction A is perpendicular to the weft insertion direction X in a plan view from the weft insertion direction X, and is the direction from the reed feathers 15 toward the sub-nozzle 12 shown in Figure 1.

[0027] In this embodiment, the opening direction A is perpendicular to the longitudinal direction and thickness direction of the reed blades 15. However, the opening direction A does not have to be perpendicular to the longitudinal direction of the reed blades 15. For example, the opening direction A may be a direction slightly inclined with respect to the longitudinal direction of the reed blades 15 and perpendicular to the thickness direction of the reed blades 15. The opening direction A is a direction that opens the guide recess 15a so that the sub-nozzle 12 shown in Figure 1 can inject air into the reed internal passage 13b, which will be described later, via the air injection port.

[0028] The reed 15 has a first passage forming surface 151, a second passage forming surface 152, and a third passage forming surface 153 as surfaces that form the guide recess 15a. The first passage forming surface 151 is the surface that forms the guide recess 15a and extends in the longitudinal direction of the reed 15. The first passage forming surface 151 faces the opening direction A of the guide recess 15a. The second passage forming surface 152 is the surface that is continuous with the first passage forming surface 151 and is closer to the tip of the reed 15. The third passage forming surface 153 is the surface that is continuous with the first passage forming surface 151 and is closer to the base of the reed 15. The second passage forming surface 152 faces the third passage forming surface 153 in the longitudinal direction of the reed 15.

[0029] The reed 15 has a first connecting surface 154 that connects the first passage forming surface 151 and the second passage forming surface 152. The first connecting surface 154 is curved and connects the first passage forming surface 151 and the second passage forming surface 152. The reed 15 also has a second connecting surface 155 that connects the first passage forming surface 151 and the third passage forming surface 153. The second connecting surface 155 is curved and connects the first passage forming surface 151 and the third passage forming surface 153. As described above, the guide recess 15a is the portion of the reed 15 formed by the first passage forming surface 151, the second passage forming surface 152, the third passage forming surface 153, the first connecting surface 154, and the second connecting surface 155.

[0030] The reed 13 has an internal passage 13b. The internal passage 13b is formed by a plurality of guide recesses 15a arranged in the weft insertion direction X. In other words, the internal passage 13b is formed by a plurality of guide recesses 15a. For this reason, it can also be said that the first passage forming surface 151, the second passage forming surface 152, the third passage forming surface 153, the first connecting surface 154, and the second connecting surface 155 of the reed feathers 15 form the internal passage 13b. Furthermore, in the reed 13, the plurality of guide recesses 15a are arranged such that, when viewed from the weft insertion direction X, the direction in which the internal passage 13b opens is the opening direction A. In other words, it can also be said that the internal passage 13b opens in the opening direction A of the guide recesses 15a.

[0031] The reed 13 and the multiple sub-nozzles 12 are aligned in the opening direction A. The multiple sub-nozzles 12 are positioned so that air can be injected from the tip of each sub-nozzle 12 toward the passage 13b inside the reed.

[0032] As shown in Figures 1 and 3, in the air jet loom 10, the warp threads T pass through the gap formed by two adjacent reed dents 15 of the reed 13. When passing through the reed 13, the multiple warp threads T are divided into warp threads T that pass closer to the tip of the reed dents 15 than the weft threads Y, and warp threads T that pass closer to the base of the reed dents 15 than the weft threads Y.

[0033] As shown in Figures 2 and 3, the vibration-dampening member 20 is positioned on the downstream portion of the reed 13. The vibration-dampening member 20 is a long, plate-like body extending in the longitudinal direction of the reed blades 15. The vibration-dampening member 20 has a hook portion 21 at one end, and this hook portion 21 is hooked onto the holding member 13a on the tip end side of the reed blades 15. The vibration-dampening member 20 is fixed to the reed 13 by the hook portion 21 being fixed to the holding member 13a by a bolt 22.

[0034] The vibration-suppressing member 20 has a vibration damping member 23 near the end opposite to the latching portion 21. The vibration damping member 23 is an elastic member. The vibration damping member 23 is a long plate-shaped body extending in the longitudinal direction of the vibration-suppressing member 20. The vibration-suppressing member 20 presses the vibration damping member 23 against a plurality of reed blades 15. The vibration-suppressing member 20 presses the vibration damping member 23 against the plurality of reed blades 15 from the side of the reed 13 that does not face the plurality of sub-nozzles 12. A reflective member 40, which will be described later, is attached to the vibration-suppressing member 20. The reflective member 40 is attached to the vibration damping member 23.

[0035] As shown in Figure 1, the air jet loom 10 injects the weft yarn Y towards the reed passage 13b using the main nozzle 11. The injected weft yarn Y flies through the reed passage 13b in the weft insertion direction X by relay air injection from multiple sub-nozzles 12. The air jet loom 10 inserts the weft yarn Y through the reed passage 13b by air injection. After the weft yarn Y has flown through the reed passage 13b, the air jet loom 10 beats the reed by oscillating the slay 14. In this way, the air jet loom 10 weaves a fabric C with the weft yarn Y and warp yarn T. The vibration of the reed blades 15 during reed beating is absorbed by the vibration damping member 23.

[0036] <Weft detection device> As shown in Figure 1, the air jet loom 10 is equipped with a weft detection device 30. Furthermore, as shown in Figures 3 and 5, the weft detection device 30 is equipped with a weft sensor 31 and a reflective member 40.

[0037] As shown in Figures 1 and 3, the weft sensor 31 is fixed to the slay 14. The weft sensor 31 is located in the downstream portion of the slay 14, and in the portion aligned with the multiple sub-nozzles 12 in the weft insertion direction X. The weft sensor 31 is positioned to face the vibration damping member 23 via the reed 13. In other words, the reed 13 is provided between the weft sensor 31 and the vibration damping member 23. The weft sensor 31 is an optical sensor. The weft sensor 31 is positioned in the weft insertion direction X where the warp thread T is outside the detection range.

[0038] As shown in Figure 3, the weft sensor 31 has a base end fixed to the slay 14 and a tip end facing the reed 13. Hereafter, the tip end of the weft sensor 31 will be referred to as the sensor end 32. The sensor end 32 is located in a position facing the vibration suppression member 20 via the reed 13.

[0039] The weft sensor 31 has a columnar sensor body 33 that extends from its base end to its sensor end 32. The base end and the tip of the sensor body 33 coincide with the base end and the sensor end 32 of the weft sensor 31, respectively. For this reason, the tip of the sensor body 33 is also referred to as the sensor end 32.

[0040] <Light-emitting unit and light-receiving unit> As shown in Figures 1 and 3, the sensor body 33 comprises a light-emitting unit 32a and a light-receiving unit 32b. The light-emitting unit 32a and the light-receiving unit 32b are provided at the sensor end 32. In other words, the weft sensor 31 is provided with the light-emitting unit 32a and the light-receiving unit 32b, each at the sensor end 32. The light-emitting unit 32a and the light-receiving unit 32b are arranged side by side in the weft insertion direction X at the sensor end 32. A cable 32c is connected to the base end of the sensor body 33. The cable 32c connects the weft sensor 31 to a control device (not shown).

[0041] As shown in Figures 3 and 5, the weft sensor 31 has its light-emitting section 32a facing the portion of the reed passage 13b closer to the base end of the reed blades 15. More specifically, when a virtual line is drawn from a point on the light-emitting section 32a in the direction in which the optical axis of the light-emitting section 32a extends, this virtual line passes through the portion of the reed passage 13b closer to the base end of the reed blades 15. For this reason, it can also be said that the weft sensor 31 is positioned with its light-emitting section 32a facing the reed passage 13b. It can also be said that the weft sensor 31 is positioned on the slay 14 such that when a virtual line is drawn from a point on the light-emitting section 32a along the direction in which the optical axis of the light-emitting section 32a extends, this virtual line passes through the reed passage 13b.

[0042] The light-emitting unit 32a is composed of light-emitting diodes. The light-emitting unit 32a is electrically connected to a control device (not shown). The light-emitting unit 32a is configured to emit light under the control of the control device.

[0043] As shown in Figure 5, the light-emitting unit 32a projects light toward the reed passage 13b. More specifically, the weft sensor 31 is equipped with a light-emitting unit 32a at the sensor end 32 such that the optical axis extending from the light-emitting unit 32a passes through the reed passage 13b. Hereafter, the point where the surface of the light-emitting unit 32a intersects with the optical axis will be referred to as the center of the light-emitting unit 32a.

[0044] Light projected from the light-emitting unit 32a and traveling to a location away from the light-emitting unit 32a illuminates a wider area compared to the area near the light-emitting unit 32a. In other words, the area illuminated by the light projected from the light-emitting unit 32a expands as you move away from the light-emitting unit 32a. Thus, the light projected from the light-emitting unit 32a toward the internal passage 13b diffuses as it moves away from the light-emitting unit 32a.

[0045] In Figure 5, the range indicated by the two dashed lines corresponds to twice the magnitude of the half-power angle of view related to the light-emitting diode of the light-emitting unit 32a. When measuring the amount of light projected from the light-emitting unit 32a from a certain distance away, the measured amount of light is greatest when measured at a position directly facing the light-emitting unit 32a. The angle at which each dashed line shown in Figure 5 is inclined with respect to the optical axis of the light-emitting unit 32a is the half-power angle of view related to the amount of light projected by the light-emitting unit 32a.

[0046] Hereafter, the area from which light is projected by the light-emitting unit 32a will be defined by the two dashed lines shown in Figure 5. In other words, from here on, the area from which light is projected by the light-emitting unit 32a is the area within the half-power angle of the light-emitting diode provided in the light-emitting unit 32a.

[0047] The light-receiving unit 32b is composed of a photodiode. The light-receiving unit 32b is electrically connected to the control device. The light-receiving unit 32b is configured to receive light. When the light-receiving unit 32b receives light, it outputs an electrical signal corresponding to the intensity of the light. This electrical signal is input to the control device via cable 32c. The magnitude of the electrical signal output by the light-receiving unit 32b increases as the intensity of the light received by the light-receiving unit 32b increases. In other words, the light-receiving unit 32b outputs a larger electrical signal by receiving stronger light.

[0048] The area shown by the two dashed lines in Figure 5 corresponds to twice the magnitude of the half-power angle of view related to the photodiode of the light-receiving unit 32b. The light-receiving unit 32b outputs the largest electrical signal to the control device when light is received by the light-receiving unit 32b along the central axis extending from the light-receiving unit 32b. The angle at which each dashed line shown in Figure 5 is inclined with respect to the central axis is the half-power angle of view related to the current output by the light-receiving unit 32b when it receives light.

[0049] The light receiving unit 32b receives the light that has been reflected within the reed passage 13b from the light projecting unit 32a onto the reed passage 13b. The light receiving unit 32b then outputs an electrical signal to the control device according to the amount of light. When the weft yarn Y enters the range detectable by the weft yarn sensor 31, the light receiving unit 32b receives the light that has been projected from the light projecting unit 32a and reflected by the weft yarn Y. As a result, the light receiving unit 32b outputs an electrical signal related to the reflected light from the weft yarn Y to the control device. This electrical signal allows the weft yarn sensor 31 to inform the control device that the weft yarn Y is flying within the detection range. In other words, the weft yarn sensor 31 can detect the weft yarn Y within the range indicated by the two dashed lines in Figure 5.

[0050] <Reflective material> As shown in Figure 4, the reflective member 40 is a plate-shaped body. The reflective member 40 is attached to the vibration suppression member 20. More specifically, as shown in Figures 2 and 3, the reflective member 40 is provided on the surface of the vibration damping member 23 that faces the reed 13, and on the portion of that surface that does not come into contact with the reed blades 15. The reflective member 40 is erected on the vibration damping member 23. The thickness direction of the reflective member 40 is perpendicular to the longitudinal direction of the vibration suppression member 20 and the thickness direction of the vibration damping member 23.

[0051] As shown in Figure 3, the reflective member 40 is installed on the air jet loom 10 by the vibration damping member 20. As shown in Figure 2, the vibration damping member 20 presses the vibration damping member 23 against the reed 13 from behind the reed 13, and inserts the reflective member 40 into the gap formed by two opposing reed blades 15. The reflective member 40 is in contact with two adjacent reed blades 15 on the reed 13 and is inserted into the gap defined by the two reed blades 15. In other words, the reflective member 40 is positioned between adjacent reed blades 15 in the weft insertion direction X. Therefore, the thickness direction of the reflective member 40 coincides with the weft insertion direction X.

[0052] As shown in Figure 3, the reflective member 40 is aligned with the reed passage 13b and the weft sensor 31 in the opening direction A. More specifically, the reflective member 40 is aligned with the sensor end 32 via the reed passage 13b in the direction from which the light projector 32a projects light. In other words, the reflective member 40 is located in the downstream portion of the slay 14. To put it another way, the weft detection device 30 is provided in the downstream portion of the slay 14 in the weft insertion direction X.

[0053] The reflective member 40 has a front surface 41. The front surface 41 is the surface of the reflective member 40 that faces the direction of the weft sensor 31. The front surface 41 extends in the longitudinal direction of the reed blades 15. The front surface 41 faces the opening direction A. In the longitudinal direction of the reed blades 15, the front surface 41 extends beyond the opening width of the guide recess 15a. The front surface 41 is aligned with the first passage forming surface 151 in a direction perpendicular to the longitudinal and thickness directions of the reed blades 15. In other words, the front surface 41 is aligned with the first passage forming surface 151 in the opening direction A of the guide recess 15a.

[0054] As shown in Figures 3 and 5, the reflective member 40 has an arc-shaped surface 45. The arc-shaped surface 45 constitutes a part of the front surface 41. The arc-shaped surface 45 is the curved portion of the front surface 41 when viewed from the latitude direction X. The arc-shaped surface 45 is concave in the direction away from the light-emitting section 32a when viewed from the latitude direction X.

[0055] The arc-shaped surface 45 is an arc centered on the light-emitting section 32a when viewed from the latitude insertion direction X. More specifically, the arc-shaped surface 45 is an arc centered on a point on the light-emitting section 32a when viewed from the latitude insertion direction X. In this embodiment, this point is the center of the light-emitting section 32a. It is preferable that this point is a point on the optical axis of the light-emitting section 32a.

[0056] As shown in Figure 5, the reflective member 40 has an arc-shaped surface 45 on the entire surface to which light is projected from the light-emitting unit 32a via the reed passage 13b. In other words, the reflective member 40 has an arc-shaped surface 45 at the position to which light is projected from the light-emitting unit 32a via the reed passage 13b. In this embodiment, the reflective member 40 also has an arc-shaped surface 45 on the front surface 41 to which light that has been projected from the light-emitting unit 32a but has not passed through the reed passage 13b reaches.

[0057] The arc-shaped surface 45 comprises, in the longitudinal direction of the reed blades 15, a portion closer to the tip of the reed blades 15 than the second passage forming surface 152, and a portion closer to the base of the reed blades 15 than the second passage forming surface 152. In other words, the reflective member 40 has the arc-shaped surface 45 in the longitudinal direction of the reed blades 15 in the portion closer to the tip of the reed blades 15 than the guide recess 15a.

[0058] Of the arc-shaped surface 45, the portion closer to the tip of the reed 15 than the second passage forming surface 152 and the portion closer to the base of the reed 15 than the second passage forming surface 152 connect to the first connecting surface 154 when viewed from the weft insertion direction X. In other words, this portion of the arc-shaped surface 45 is flush with the first connecting surface 154. That is, the reflective member 40 has a portion of the arc-shaped surface 45 that is flush with the surface of the reed 15 adjacent to the reflective member 40 that forms the internal passage 13b of the reed.

[0059] The reflective member 40 is positioned so as to not overlap with the internal reed passage 13b when viewed from the weft insertion direction X. In other words, the reflective member 40 is provided on the reed 13 so as not to intersect with the surface forming the internal reed passage 13b when viewed from the weft insertion direction X.

[0060] The arc-shaped surface 45 reflects light projected from the light-emitting section 32a through the reed passage 13b toward the light-receiving section 32b. More specifically, when the weft yarn Y is flying through the reed passage 13b, the light not reflected by the weft yarn Y passes through the reed passage 13b and then reaches the arc-shaped surface 45. The light that reaches the arc-shaped surface 45 is reflected by the arc-shaped surface 45, then passes through the reed passage 13b again and travels toward the outside of the reed 13. Of the light reflected by the arc-shaped surface 45, the light with the light-receiving section 32b in front of it in the direction of travel is received by the light-receiving section 32b.

[0061] [Operation of this embodiment] The operation of this embodiment will now be explained. The air jet loom 10 inserts the weft yarn Y through the reed passage 13b formed in the reed 13 by the injection of air. The weft sensor 31 of the weft detection device 30 projects light toward the reed passage 13b using a light-emitting unit 32a. The light projected by the light-emitting unit 32a is reflected by the reed passage 13b and then received by the light-receiving unit 32b. If the weft yarn Y is flying within the range where the light-emitting unit 32a projects light and within the range where the light-receiving unit 32b can detect light, the weft sensor 31 receives the light reflected by the weft yarn Y with the light-receiving unit 32b. In this way, the weft sensor 31 detects the weft yarn Y.

[0062] The reflective member 40 of the weft detection device 30 has an arc-shaped surface 45 at a position where light is projected from the light-emitting unit 32a through the reed internal passage 13b. The arc-shaped surface 45 reflects the light projected from the light-emitting unit 32a toward the light-receiving unit 32b.

[0063] [Effects of this embodiment] The effects of this embodiment will now be explained. (1) Light projected from the light-emitting unit 32a passes through the reed passage 13b and is then reflected by the arc-shaped surface 45 in the direction toward the light-receiving unit 32b. The light reflected by the arc-shaped surface 45 passes through the reed passage 13b again and is then detected by the light-receiving unit 32b. For example, compared to the case where the surface of the reflective member 40 that is positioned where light is projected from the light-emitting unit 32a through the reed passage 13b is made up of a flat surface, the amount of reflected light that the weft detection device 30 receives with the light-receiving unit 32b increases.

[0064] Furthermore, since the arc-shaped surface 45 is concave in the direction away from the light-emitting section 32a when viewed from the weft insertion direction X, the diffusion of light reflected by the arc-shaped surface 45 due to the reflection can be suppressed. In other words, by having an arc-shaped surface 45, the reflective member 40 can reduce the difference in the amount of light received by the light-receiving section 32b that depends on the location where the light is reflected. As a result, the weft detection device 30 can suppress a decrease in the detection performance of the weft Y depending on the position in which the weft Y is flying through the reed passage 13b. Therefore, the weft detection device 30 of the air jet loom 10 can improve the detection performance of the weft Y.

[0065] (2) The reflective member 40 reflects light that has passed through the portion of the reed passage 13b closer to the tip of the reed blades 15. The portion of the reed passage 13b closer to the tip of the reed blades 15 is further from the light-emitting unit 32a than the other portions of the reed passage 13b. In other words, by having an arc-shaped surface 45 closer to the tip of the reed blades 15, the reflective member 40 can suppress the decrease in the amount of reflected light even in a location far from the light-emitting unit 32a. As a result, the weft detection device 30 of the air jet loom 10 can improve the detection performance of the weft Y in the portion of the reed passage 13b where detection of the weft Y is relatively difficult.

[0066] (3) The arc-shaped surface 45 is an arc with its center at the light-emitting section 32a when viewed from the weft insertion direction X. This prevents the light projected from the light-emitting section 32a from traveling on a path that deviates from the path it took when incident on the arc-shaped surface 45 when viewed from the weft insertion direction X. As a result, the reflective member 40 can prevent the light projected from the light-emitting section 32a from reaching a different location than the light-receiving section 32b due to reflection at the arc-shaped surface 45. This prevents the weft detection device 30 of the air jet loom 10 from experiencing differences in the amount of light received by the light-receiving section 32b that depend on the location where the light is reflected. As a result, the weft detection device 30 can prevent a decrease in the detection performance of the weft Y even when the weft Y is traveling at a distance from the light-emitting section 32a within the reed passage 13b. Based on the above, the weft detection device 30 of the air jet loom 10 can improve the detection performance of the weft Y in the reed passage 13b.

[0067] (4) Compared to the case where the reflective member 40 has an arc-shaped surface 45 only on a portion of the surface from which light is projected from the light-emitting unit 32a through the reed passage 13b, the amount of light received by the light-receiving unit 32b can be made less dependent on the location where the light is reflected. As a result, the weft detection device 30 of the air jet loom 10 can improve the detection performance of the weft Y throughout the entire reed passage 13b.

[0068] (5) The reflective member 40 is positioned between the reed blades 15 such that the distance from the light-emitting unit 32a is shortened by the portion of the reflective member 40 that is flush with the surface forming the reed passage 13b, and that it does not overlap with the reed passage 13b in the weft insertion direction X. In other words, the reflective member 40 can shorten the path of light from the light-emitting unit 32a to the light-receiving unit 32b via the arc-shaped surface 45 without interfering with the flight of the weft yarn Y in the reed passage 13b. In other words, the weft detection device 30 of the air jet loom 10 can improve the detection performance of the weft yarn Y in the reed passage 13b without interfering with the insertion of the weft yarn Y.

[0069] [Example of changes] The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0070] ○ The reflective member 40 does not need to have an arc-shaped surface 45 over the entire surface on which light is projected from the light-emitting section 32a via the internal passage 13b of the reed. In other words, the reflective member 40 may have an arc-shaped surface 45 on only a portion of the surface on which light is projected from the light-emitting section 32a via the internal passage 13b of the reed.

[0071] As shown in Figures 6 and 7, for example, the reflective member 40 may be configured such that the portion of the reed blade 15 closer to the base end than the arcuate surface 45 in the longitudinal direction of the reed blade 15 is composed of a straight surface 46 extending in the longitudinal direction of the reed blade 15. In this case, the front surface 41 of the reflective member 40 has both an arcuate surface 45 and a straight surface 46. Furthermore, the surface of the reflective member 40 from which light is projected from the light-emitting section 32a via the reed internal passage 13b is composed of both an arcuate surface 45 and a straight surface 46.

[0072] The linear surface 46 extends in the longitudinal direction of the reed 15 and is parallel to the first passage forming surface 151. The reflective member 40 is provided on the reed 13 such that, when viewed from the weft insertion direction X, the arc-shaped surface 45 is closer to the tip of the reed 15 than the second passage forming surface 152, and the linear surface 46 overlaps with the first passage forming surface 151. In other words, when viewed from the weft insertion direction X, the linear surface 46 is flush with the first passage forming surface 151. Therefore, the reflective member 40 is provided at a position where the linear surface 46 is flush with the surface of the reed 15 adjacent to the reflective member 40 that defines the internal passage 13b of the reed and faces the opening direction of the guide recess 15a.

[0073] For example, if the reflective member 40 is provided at a position away from the reed passage 13b, the reflective member 40 and the adjacent reed blades 15 form a groove that communicates with the reed passage 13b. More specifically, if the reflective member 40 is provided on the reed 13 such that the straight surface 46 is at a position away from the first passage forming surface 151, the reflective member 40 and the two reed blades 15 form a groove. In the air jet loom 10, wind fumes generated from the weft yarn Y, which is a spun yarn, may be captured by this groove. When the weft detection device 30 provides the reflective member 40 on the reed 13, by making the straight surface 46 and the first passage forming surface 151 flush, wind fume clogging caused by the groove formed by the reflective member 40 and the two reed blades 15 can be suppressed. In other words, the weft detection device 30 can suppress the surface of the reflective member 40 from which light is projected from the light-emitting section 32a from being covered by wind fumes. This makes it possible to suppress the decrease in the detection performance of the weft yarn Y by the wind-blown cotton in the weft yarn detection device 30 of the air-jet loom 10.

[0074] ○ The reflective member 40 does not need to have a portion of the arc-shaped surface 45 that is flush with the surface of the reed blades 15 adjacent to the reflective member 40 that forms the reed internal passage 13b. ○ The reflective member 40 may be positioned so as to overlap with the reed passage 13b when viewed from the weft insertion direction X. The reflective member 40 should be positioned so as not to obstruct the flight of the weft Y in the reed passage 13b.

[0075] ○ The weft sensor 31 does not necessarily have to position its light-emitting section 32a opposite the portion of the reed passage 13b that is closer to the base end of the reed blades 15. For example, the weft sensor 31 may position its light-emitting section 32a opposite the central portion of the reed passage 13b in the longitudinal direction of the reed blades 15. In short, the weft sensor 31 only needs to have its light-emitting section 32a positioned so that it can project light onto the reed passage 13b.

[0076] ○ The arc-shaped surface 45 does not have to be an arc with its center at the light-emitting section 32a when viewed from the latitude direction X. For example, the arc-shaped surface 45 does not have to be an arc with its center at the light-receiving section 32b. Furthermore, the arc-shaped surface 45 may be an arc with its center at the portion of the sensor end 32 where the light-emitting section 32a and the light-receiving section 32b are not provided.

[0077] ○ The arc-shaped surface 45 does not have to be a circular arc. In this case, the arc-shaped surface 45 may be composed of multiple curves, each with a different curvature when viewed from the weft insertion direction X. ○ The weft detection device 30 does not have to be installed in the downstream portion of the slay 14 in the weft insertion direction X. Preferably, the weft detection device 30 is installed downstream of the end of the woven fabric C produced by the air jet loom 10 that is located downstream in the weft insertion direction X.

[0078] ○ The reflective member 40 does not necessarily have to be attached to the air jet loom 10 by the vibration suppression member 20. For example, the reflective member 40 may be inserted between two adjacent reeds 15 and also held between the two reeds 15. Alternatively, the reflective member 40 may be inserted between two adjacent reeds 15 and also bonded to the two reeds 15.

[0079] ○ The weft detection device 30 may have multiple reflective members 40. In this case, the multiple reflective members 40 may be attached to the vibration suppression member 20. Alternatively, the air jet loom 10 may have multiple vibration suppression members 20 attached to it, and each vibration suppression member 20 may be provided with a reflective member 40. [Explanation of Symbols]

[0080] 10...Air jet loom, 13...Reed, 13b...Reed passage, 14...Slay, 15...Reed blades, 15a...Guide recess, 30...Weft detection device, 31...Weft sensor, 32...Sensor end, 32a...Light emitting part, 32b...Light receiving part, 40...Reflective member, 45...Arch-shaped surface, A...Opening direction, X...Weft insertion direction, Y...Weft, 46...Straight surface.

Claims

1. A weft detection device for an air jet loom, comprising a reed having multiple rows of reed blades having guide recesses arranged in the weft insertion direction, wherein the weft yarn is inserted through a passage inside the reed formed by the multiple guide recesses by the injection of air, A weft sensor is provided with a light-emitting section that projects light toward the internal passage of the reed and a light-receiving section that receives light, each of which is located at the sensor end, and the sensor end is positioned facing the internal passage of the reed. The reflective member is positioned between adjacent reed blades in the weft insertion direction, and is provided at a location where light is projected from the light-emitting section through the reed internal passage, and has an arc-shaped surface that reflects the light projected from the light-emitting section toward the light-receiving section. The arc-shaped surface is concave in the direction away from the light-emitting section when viewed from the direction of weft insertion, in the weft detection device for an air jet loom.

2. The reed feathers have a base end connected to the sleigh, and a tip end on the opposite side of the base end in the longitudinal direction. The weft sensor is fixed to the sleigh, and the light-emitting part is positioned opposite the portion of the reed passage closer to the base end of the reed blades. The reflective member has the arc-shaped surface in the longitudinal direction of the reed blades, in a portion closer to the tip of the reed blades than the guide recess. The weft detection device for an air jet loom according to claim 1, wherein the arc-shaped surface is an arc shape centered on the light-emitting part when viewed from the direction of weft insertion.

3. The weft detection device for an air jet loom according to claim 2, wherein the reflective member has the arc-shaped surface on the entire surface from which light is projected from the light-emitting unit through the reed passage.

4. The weft detection device for an air jet loom according to claim 2 or 3, wherein the reflective member has a portion on the arc-shaped surface that is flush with the surface of the reed blade adjacent to the reflective member that forms the reed passage, and is provided at a position that does not overlap with the reed passage when viewed from the weft insertion direction.

5. The weft detection device for an air jet loom according to claim 2, wherein the reflective member is configured such that the portion of the reflective member closer to the base end than the arc-shaped surface in the longitudinal direction of the reed blade is composed of a straight surface extending in the longitudinal direction of the reed blade, and the reflective member is provided in a position adjacent to the reed blade where the surface that defines the internal passage of the reed and faces the opening direction of the guide recess and the straight surface are flush.

Images