CN109957872B - Weft yarn detection method for air jet loom - Google Patents
Weft yarn detection method for air jet loom Download PDFInfo
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- CN109957872B CN109957872B CN201811516229.5A CN201811516229A CN109957872B CN 109957872 B CN109957872 B CN 109957872B CN 201811516229 A CN201811516229 A CN 201811516229A CN 109957872 B CN109957872 B CN 109957872B
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- D—TEXTILES; PAPER
- D03—WEAVING
- D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
- D03D47/00—Looms in which bulk supply of weft does not pass through shed, e.g. shuttleless looms, gripper shuttle looms, dummy shuttle looms
- D03D47/28—Looms in which bulk supply of weft does not pass through shed, e.g. shuttleless looms, gripper shuttle looms, dummy shuttle looms wherein the weft itself is projected into the shed
- D03D47/30—Looms in which bulk supply of weft does not pass through shed, e.g. shuttleless looms, gripper shuttle looms, dummy shuttle looms wherein the weft itself is projected into the shed by gas jet
- D03D47/3066—Control or handling of the weft at or after arrival
- D03D47/3073—Detection means therefor
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- D—TEXTILES; PAPER
- D03—WEAVING
- D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
- D03D51/00—Driving, starting, or stopping arrangements; Automatic stop motions
- D03D51/18—Automatic stop motions
- D03D51/34—Weft stop motions
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Abstract
The invention aims to provide a weft yarn detection method of an air jet loom, which can simply detect the occurrence of reverse folding. A first weft detection range (P1) set after the weft insertion start time and before the weft insertion end time, a second weft detection range (P2) set within the first weft detection range (P1) and after the time when a weft is gripped by a selvedge yarn, a first pulse threshold (S1) which is a threshold of a detection signal in the first weft detection range (P1), and a second pulse threshold (S2) which is a threshold of a detection signal in the second weft detection range (P2) are set. When the detection signal of the RH weft feeler is equal to or greater than the first pulse threshold (S1) in the first weft detection range (P1) and is not equal to or greater than the second pulse threshold (S2) in the second weft detection range (P2), it is determined that the weft yarn is reversed.
Description
Technical Field
The present invention relates to a weft detecting method for an air jet loom.
Background
In the air jet loom, there is a case where the weft inserted reaches the weaving end opposite to the weft insertion side, and then the weft is folded back in the fabric for some reason. A weft detecting method capable of detecting this reverse turn is known.
In the weft detecting method described in patent document 1, in an air jet loom having an integrator that integrates a detection signal output from a weft detecting device, a discharge time constant of the integrator is set in accordance with the flexibility of a weft. When the detection signal of the integrator disappears due to the setting, the level of the integration signal is rapidly lowered, whereby the control signal is lowered to detect the occurrence of the reverse turn.
In the weft detecting method described in patent document 2, three weft detecting devices are provided in parallel along a weft path. Then, the weft insertion state is determined by a combination of detection signals output from the weft detecting devices, and occurrence of a reverse turn is detected.
Patent document 1: japanese laid-open patent publication No. 11-189953
Patent document 2: japanese laid-open patent publication No. 59-187647
However, in the weft detecting method described in patent document 1, it is necessary to appropriately set the discharge time constant of the integrator in accordance with the flexibility of the weft, but the specifically set discharge time constant needs to be adjusted in accordance with the properties such as the flexibility of the weft to be used, and this adjustment is difficult.
In addition, the weft detecting method described in patent document 2 requires a plurality of weft detecting devices, and has a problem of increasing the component cost and the number of production steps of the air jet loom.
Disclosure of Invention
The present invention has been made to solve the above problems, and an object thereof is to provide a weft detecting method capable of easily detecting the occurrence of a reverse turn.
In order to solve the above-mentioned problems, a weft detecting method for an air jet loom according to the present invention is a weft detecting method for an air jet loom in which an optical weft detecting device for detecting a weft inserted into a weaving end portion on the opposite side to the weft insertion side and outputting a detection signal is provided, setting a first weft detection range set after a weft insertion start time and before a weft insertion end time, a second weft detection range set within the first weft detection range and after a time when a warp holds a weft, a first threshold value which is a threshold value of a detection signal in the first weft detection range, and a second threshold value which is a threshold value of a detection signal in the second weft detection range, when the detection signal is equal to or greater than a first threshold value in the first weft detection range and is less than a second threshold value in the second weft detection range, it is determined that a reverse turn of the weft yarn has occurred.
The detection signal may be a pulse signal, and the first threshold value and the second threshold value may be set by the number of pulse signals.
The detection signals may be pulse signals and level signals, and the first threshold value and the second threshold value may be set by the number of pulse signals and the value of the level signal, respectively, and may be set by the number of pulse signals or the value of the level signal in the first weft detection range, respectively.
In addition, it may be determined that a weft insertion error of a weft yarn has occurred when the detection signal is less than the first threshold value in the first weft yarn detection range and less than the second threshold value in the second weft yarn detection range.
In the weft detecting method of the air jet loom according to the present invention, the first weft detecting range set after the weft insertion start time and before the weft insertion end time, the second weft detecting range set after the time when the warp holds the weft in the first weft detecting range, the first threshold value which is the threshold value of the detection signal in the first weft detecting range, and the second threshold value which is the threshold value of the detection signal in the second weft detecting range are set, and when the detection signal is equal to or more than the first threshold value in the first weft detecting range and is less than the second threshold value in the second weft detecting range, it is determined that the reverse of the weft is generated, so that the occurrence of the reverse can be easily detected.
Drawings
Fig. 1 is a schematic view of the vicinity of a woven end of a fabric according to embodiment 1 of the present invention.
Fig. 2A is a schematic view showing a weft insertion state of the weft yarn Y shown in fig. 1.
Fig. 2B is a schematic view showing a weft insertion state of the weft yarn Y shown in fig. 1.
Fig. 2C is a schematic view showing a weft insertion state of the weft yarn Y shown in fig. 1.
Fig. 3 is a timing chart showing the detection operation of the weft yarn Y shown in fig. 2.
Fig. 4A is a diagram showing a method of detecting a level signal of the RH weft feeler 93 shown in fig. 1.
Fig. 4B is a diagram showing a method of detecting a level signal of the RH weft feeler 93 shown in fig. 1.
Fig. 4C is a diagram showing a method of detecting a level signal of the RH weft feeler 93 shown in fig. 1.
Description of the reference numerals
Weaving the end portion; 53.. warp yarns; weaving selvage yarns (warp yarns); 91. 93.. RH feeler; p1.. first weft detection range; p2.. second weft detection range; s1.. a first pulse threshold (first threshold); s2.. a second pulse threshold (second threshold); s3.. first level threshold (first threshold); s4.. second level threshold (second threshold); y, Y1, Y2..
Detailed Description
Hereinafter, a weft detecting method in an air jet loom according to embodiment 1 of the present invention will be described with reference to the drawings.
Fig. 1 shows a weaving end portion on the opposite side to the weft insertion side of the air jet loom. The sley 10 is fixed to a rocker shaft (not shown) via a sley leg (not shown). The sley 10 swings in the front-back direction of the loom. The reed 20 attached to the slay 10 has a weft yarn guide passage 40 opening toward the fell 30 side. A temple device 60 is provided so as to straddle the knitted end 51 and the selvage 52 of the fabric 50.
The weft yarn Y passing through the temple device 60 and between the fabric 50 and the selvage 52 is cut by the cutter 70 provided between the fabric 50 and the selvage 52. The weft yarn Y is fed by a main nozzle and a duplex nozzle, not shown. A plurality of auxiliary nozzles 80 for conveying the weft yarn Y introduced with weft yarns are provided at intervals on the slay 10.
An RH weft feeler 91 is disposed between the warp yarn 53 at the position of the weaving end 51 of the fabric 50 on the sley 10 and the selvage yarn 54 as the warp yarn at the position of the selvage 52. A W weft detector 92 is disposed on the RH weft detector 91 with the selvedge yarn 54 interposed therebetween. In addition, the warp yarn 53 and the selvage yarn 54 constitute a warp yarn.
The RH weft feeler 91 and the W weft feeler 92 include: a projection unit having a light emitting element and the like, not shown, and a light receiving unit having a light receiving element and the like, not shown. The RH and W feelers 91 and 92 are disposed such that the projecting portion and the light receiving portion face the weft guide passage 40 of the reed 20. The RH and W weft detectors 91 and 92 are reflective optical sensors that detect the weft yarn Y by reflecting light emitted from the projection unit by the weft yarn Y and receiving the light by the light receiving unit, and output a detection signal as a pulse signal. The RH weft feeler 91 constitutes an optical weft detecting device.
The RH weft feeler 91 and the W weft feeler 92 are electrically connected to a main control device 100 of the air jet loom. The RH weft feeler 91 detects that the weft yarn Y is conveyed to the position of the selvedge 52. The W weft detector 92 detects a state in which the weft yarn Y is conveyed to an abnormal position beyond the position of the selvedge 52, such as a case where a weft breakage occurs when the weft yarn Y is cut or a case where an extra weft yarn Y is conveyed.
Next, weft insertion operation of the air jet loom according to embodiment 1 will be described.
As shown in fig. 1, the RH weft feeler 91 detects the weft yarn Y during weft insertion and outputs a detection signal of a pulse signal to the main control device 100. The main control device 100 counts the number of pulses of the detection signal.
The weft insertion state of the weft yarn Y will be described with reference to fig. 2A to 2C. In fig. 2A to 2C, for convenience of explanation, the RH weft feeler 91 and the W weft feeler 92 shown in fig. 1 are shown above the weft guide passage 40, and some of the components shown in fig. 1 are omitted.
As shown in fig. 2A, the weft yarn Y is transported in the direction a in the weft guide passage 40. By this conveyance, the weft yarn Y moves at the position of the selvage yarn 54. During this movement, the selvage yarn 54 crosses the weft yarn Y, and the selvage yarn 54 holds the weft yarn Y. Thereafter, the weft insertion is normally ended. At this time, the weft yarn Y is detected by the RH weft feeler 91 before the selvage yarn 54 grips the weft yarn Y, and is also detected after gripping the weft yarn Y. Further, the weft yarn Y is at a position where the W-feeler 92 cannot detect.
On the other hand, as shown in fig. 2B, the weft yarn Y is conveyed to the position of the selvage yarn 54 and arrives at the same time, but there is a case where the weft yarn Y is folded back without being gripped by the selvage yarn 54 like the weft yarn Y1 due to some reason such as the influence of the stretchability of the weft yarn Y. In the compromise shown in fig. 2B, after the time when the weft yarn Y is originally gripped by the selvage yarn 54, the weft yarn Y is detected by the RH weft feeler 91 and is at a position where the W weft feeler 92 cannot detect. In addition, in this reverse turn, the weft yarn Y does not return to the fabric 50, and therefore does not become a cloth defect.
As shown in fig. 2C, there is a case where the weft Y reaches the position of the selvedge yarn 54 at a time, but the weft Y is not held by the selvedge yarn 54 and returns to the inside of the fabric 50 like the weft Y2, although a cloth defect reverse turn is generated. In the compromise shown in fig. 2C, after the time when the weft yarn Y is originally held by the selvage yarn 54, the weft yarn Y is in a position not detected by the RH feeler 91 and the W feeler 92.
Next, a method of detecting and determining the weft yarn Y by the RH weft feeler 91 will be described.
As described above, when the weft insertion is normally performed as shown in fig. 2A, the weft yarn Y is detected by the RH weft feeler 91 before the selvedge yarn 54 grips the weft yarn Y, and is also detected after gripping the weft yarn Y. Therefore, by determining the detection signals of the RH weft feeler 91 after the weft insertion start time and before the selvage yarn 54 grips the weft yarn Y and after the gripping yarn Y, it is possible to determine that the weft insertion is normally performed.
Specifically, as shown in fig. 3, the main control device 100 counts the number of pulses of the detection signal output from the RH weft feeler 91 (see fig. 1) between the first detection start time T1 and the second detection start time T2, and between the second detection start time T2 and the detection end time T3. The first detection start time T1, the second detection start time T2, and the detection end time T3 are preset in accordance with the rotation angle of the crank of the air jet loom. The first detection start time T1 is set after the weft insertion start time. The second detection start time T2 is a time when the selvage yarn 54 grips the weft yarn Y at the time of normal weft insertion. The detection end time T3 is set before the weft insertion end time. The "gripping" at the second detection start time T2 includes not only a case where the selvage yarn 54 completely contacts the weft yarn Y, but also a case where a braking force acts between the selvage yarn 54 and the weft yarn Y due to pile of the selvage yarn 54 or the weft yarn Y.
First, as shown in example 1 of fig. 3, a case where weft insertion is normally performed will be described. Further, the period from the first detection start time T1 to the detection end time T3 is set as the first weft detection range P1, and the period from the second detection start time T2 to the detection end time T3 is set as the second weft detection range P2. That is, the second weft detecting range P2 is set within the first weft detecting range P1. In addition, the threshold value of the number of pulse signals that determines that the weft yarn Y is at the position of the RH weft feeler 91 in the first weft detection range P1 is set as the first pulse threshold value S1. In embodiment 1, the value of the first pulse threshold value S1 is set to 13 pulses. Then, the threshold value of the number of pulse signals that determines that the weft yarn Y is at the position of the RH weft feeler 91 in the second weft detection range P2 is set as the second pulse threshold value S2. In embodiment 1, the value of the second pulse threshold value S2 is set to 5 pulses. The first pulse threshold value S1 constitutes a first threshold value, and the second pulse threshold value S2 constitutes a second threshold value.
When weft insertion is performed normally, the weft yarn Y is conveyed to the position of the selvedge yarn 54 until the second detection start time T2. Therefore, in the first weft detecting range P1, since the weft yarn Y is detected by the RH weft feeler 91, the pulses of the detection signals are detected by the number equal to or more than 13 pulses (15 pulses in this example 1) which is the preset first pulse threshold S1.
Since the weft insertion is performed normally, the weft yarn Y is held continuously after the second detection start time T2, and the reverse turn to the fabric 50 is not generated. Therefore, in the second weft detection range P2, the weft yarn Y is detected by the weft feeler 91 for a sufficient time RH, and thus the preset second pulse threshold S2, that is, pulses of the detection signals of the number equal to or more than 5 pulses (5 pulses in this example 1) are detected.
That is, when the detection signal is equal to or greater than the first pulse threshold value S1 in the first weft detection range P1 and equal to or greater than the second pulse threshold value S2 in the second weft detection range P2, the main control device 100 determines that the weft insertion is performed normally. The number of pulses of the first pulse threshold value S1 and the second pulse threshold value S2 may be arbitrarily changed depending on the weft yarn Y to be detected, the configuration of the air jet loom, and the like.
Next, as shown in example 2 of fig. 3, a case where a weft insertion error occurs will be described. At this time, the weft yarn Y does not reach the position of the selvage yarn 54 due to the weft insertion error. Therefore, in both the first weft detecting range P1 and the second weft detecting range P2, the weft yarn Y is not detected by the RH weft feeler 91. Therefore, the detection signal is less than the first pulse threshold value S1, i.e., 13 pulses in the first weft detection range P1, and less than the second pulse threshold value S2, i.e., 5 pulses in the second weft detection range P2.
That is, when the detection signal is less than the first pulse threshold value S1 in the first weft detection range P1 and the detection signal is less than the second pulse threshold value S2 in the second weft detection range P2, the main control device 100 determines that a weft insertion error has occurred.
Next, as shown in example 3 of fig. 3, a case where a reverse turn occurs will be described. In example 3, the timing of weft yarn Y conveyance is earlier, and weft yarn Y reaches the position of selvage yarn 54 before second detection start timing T2. Thus, the weft yarn Y is detected by the RH weft feeler 91. At this time, the pulses of the detection signal equal to or larger than 13 pulses (15 pulses in example 3) which is the first pulse threshold S1 are detected from the first detection start time T1 to the second detection start time T2.
After the second detection start time T2, the weft yarn Y returns to the fabric 50 side and is therefore not detected by the RH weft feeler 91. Therefore, in the second weft detection range P2, the weft yarn Y is not detected by the RH weft feeler 91, and thus the detection signal is less than the second pulse threshold S2, i.e., 5 pulses.
That is, when the detection signal is equal to or greater than the first pulse threshold value S1 in the first weft detection range P1 and the detection signal is less than the second pulse threshold value S2 in the second weft detection range P2, the main control device 100 determines that a reverse turn has occurred.
In this way, in the weft detecting method of the air jet loom in which the optical weft detecting device for detecting the weft Y inserted and outputting the detection signal is provided at the weaving end 51 on the opposite side to the weft insertion side, when the first weft detecting range P1 set after the weft insertion start time and before the weft insertion end time, the second weft detecting range P2 set after the time when the selvedge yarn 54 holds the weft Y in the first weft detecting range P1, the first pulse threshold S1 which is the threshold of the detection signal in the first weft detecting range P1, and the second pulse threshold S2 which is the threshold of the detection signal in the second weft detecting range P2 are set, the detection signal is equal to or greater than the first pulse threshold S1 in the first weft detecting range P1, and the second pulse threshold S2 or greater in the second weft detecting range P2, since it is determined that the reverse turn of the weft yarn Y has occurred, the occurrence of the reverse turn can be easily detected.
Further, since the detection signal is a pulse signal and the first pulse threshold value S1 and the second pulse threshold value S2 are set in accordance with the number of pulse signals, the weft yarn Y can be detected with high accuracy.
In addition, when the detection signal is less than the first pulse threshold value S1 in the first weft detection range P1 and less than the second pulse threshold value S2 in the second weft detection range P2, it is determined that the weft insertion error of the weft yarn Y has occurred, and therefore, not only the reverse of the weft yarn Y but also the weft insertion error can be detected.
Embodiment 2.
Next, a weft detecting method in an air jet loom according to embodiment 2 of the present invention will be described. In the following embodiments, the same reference numerals as those in fig. 1 to 3 denote the same or similar components, and therefore, detailed description thereof will be omitted.
A weft detecting method of an air jet loom according to embodiment 2 is a method in which a pulse signal and a level signal are used in combination as a detection signal of a weft Y, and a threshold value of the detection signal is set as the number of pulse signals and the level signal value, as compared to embodiment 1.
As shown in fig. 1, in the air jet loom, an RH weft feeler 93 is disposed instead of the RH weft feeler 91 disposed in embodiment 1. Further, reference numerals of the RH weft feeler 93 are shown in parentheses in fig. 1. The RH weft feeler 93 is a reflective optical sensor having a projecting portion and a light receiving portion arranged at the same position as the RH weft feeler 91, and outputs a detection signal as a level signal. The RH weft feeler 93 is electrically connected to the main control device 200. In addition, reference numerals of the main control device 200 are shown in parentheses in fig. 1. The RH weft feeler 93 constitutes an optical weft detecting device. The other structure is the same as embodiment 1.
Next, a method of detecting and determining the weft yarn Y will be described with reference to fig. 2A to 2C.
As in embodiment 1, the weft yarn Y is conveyed in the direction of arrow a as shown in fig. 2A to 2C. Fig. 2A shows a case where the weft yarn Y is normally transported in the direction of arrow a. At this time, the weft yarn Y is at a position detected by the RH weft detector 93. In addition, reference numerals of the RH weft feeler 93 and reference numerals of the main control device 200 are shown in parentheses in fig. 2A to 2C.
Fig. 2B shows a case where, after weft yarn Y is conveyed in the direction of arrow a, a reverse turn is generated like weft yarn Y1, but weft yarn Y is not returned to fabric 50. At this time, the weft yarn Y is at a position detected by the RH weft detector 93.
Fig. 2C shows a case where a reverse fold occurs in the weft yarn Y after being conveyed in the direction of arrow a, and the weft yarn Y returns to the fabric 50 as in the weft yarn Y2, and a reverse fold that becomes a cloth defect occurs. At this time, the weft yarn Y is at a position not detected by the RH weft detector 93.
Next, a method of detecting the weft yarn Y by the RH weft feeler 93 will be described.
In the case where the air jet loom uses a stretch nozzle, it is sometimes difficult to emit a detection signal for detection based on a pulse signal in general. In such a case, the presence or absence of the weft yarn Y can be determined by detecting the weft yarn Y based on the level signal. On the other hand, when the weft yarn Y is a black yarn or a spun yarn, detection based on the pulse signal is generally more excellent. Therefore, as described below, the method of detecting the weft yarn Y by the RH weft feeler 93 uses both the detection based on the level signal and the detection based on the pulse signal.
As shown in fig. 4A, the RH weft detector 93 outputs a detection signal of the weft Y as a level signal. Here, the vertical axis of fig. 4A to 4C corresponds to the intensity of the level signal, and the horizontal axis corresponds to the detection start time (see fig. 3) set in advance according to the rotation angle of the crank of the air jet loom. The intensity of the level signal becomes high when the weft yarn Y is detected by the RH weft feeler 93, and becomes low when the weft yarn Y is not detected by the RH weft feeler 93.
As shown in fig. 4B, the main control device 200 full-wave rectifies the level signal output from the RH weft feeler 93. Thereby, a pulse signal of the detection signal can be obtained.
In the first weft detection range P1 (see fig. 3), the threshold value of the level signal value that determines that the weft yarn Y is at the position of the RH weft feeler 93 is set as the first level threshold value S3. In the second weft detection range P2, the threshold of the level signal value that determines that the weft yarn Y is at the position of the RH weft feeler 93 is set as the second level threshold S4. The first pulse threshold S1 and the first level threshold S3 constitute a first threshold, and the second pulse threshold S2 and the second level threshold S4 constitute a second threshold.
The main controller 200 determines whether or not the number of pulse signals is equal to or greater than a first pulse threshold value S1 in the first weft detection range P1, and determines whether or not the level signal value is equal to or greater than a first level threshold value S3. If the number of pulse signals is equal to or greater than the first pulse threshold value S1 or the level signal value is equal to or greater than the first level threshold value S3, it is determined that the weft yarn Y is at the position of the RH weft detector 93 in the first weft detection range P1.
In addition, the main controller 200 determines whether or not the number of pulse signals is equal to or greater than the second pulse threshold value S2 and whether or not the level signal value is equal to or greater than the second level threshold value S4 in the second weft detection range P2. If either the pulse signal number or the level signal value is equal to or greater than the threshold value, it is determined that the weft yarn Y is at the position of the RH weft detector 93 in the second weft detection range P2.
The method of determining whether or not a weft Y is folded back in the first weft detection range P1 and the second weft detection range P2 is the same as that of embodiment 1. That is, when weft insertion is performed normally, the weft yarn Y is conveyed to the position of the selvage yarn 54 until the second detection start time T2. Therefore, in the first weft detecting range P1, the weft yarn Y is detected by the RH weft feeler 93. Then, the main control device 200 detects at least either one of the number of pulses of the detection signal equal to or greater than the preset first pulse threshold value S1 or the level signal value of the detection signal equal to or greater than the preset first level threshold value S3.
Since the weft insertion is normal, the weft yarn Y continues to be gripped after the second detection start time T2, and the fabric 50 is not folded back. Therefore, in the second weft detection range P2, the weft yarn Y is detected by the RH weft feeler 93 for a sufficient time, and therefore the main control device 200 detects at least either the number of pulses of the detection signal equal to or greater than the preset second pulse threshold value S2 or the level signal value of the detection signal equal to or greater than the preset second level threshold value S4.
That is, the main control device 200 determines that the weft insertion is normal when the number of pulses of the detection signal is equal to or greater than the first pulse threshold S1 or the level signal value of the detection signal is equal to or greater than the first level threshold S3 in the first weft detection range P1, and the number of pulses of the detection signal is equal to or greater than the second pulse threshold S2 or the level signal value of the detection signal is equal to or greater than the second level threshold S4 in the second weft detection range P2.
Next, a case where a weft insertion error occurs will be described. In the case where the weft yarn Y does not reach the position of the selvedge yarn 54 due to the weft insertion error, the weft yarn Y is not detected by the RH weft feeler 93 in both the first weft detection range P1 and the second weft detection range P2. Therefore, in the first weft detecting range P1, the pulse of the detection signal detected by the main control device 200 is less than the first pulse threshold value S1, and the level signal value of the detection signal is less than the first level threshold value S3. In addition, the pulse of the detection signal detected by the main control device 200 in the second weft detecting range P2 is less than the first level threshold S3, and the level signal value of the detection signal is less than the second level threshold S4.
That is, in the case where the number of pulses of the detection signal is less than the first pulse threshold S1 and the level signal value of the detection signal is less than the first level threshold S3 in the first weft detection range P1, and the number of pulses of the detection signal is less than the second pulse threshold S2 and the level signal value of the detection signal is less than the second level threshold S4 in the second weft detection range P2, the main control device 200 determines that a weft insertion error has occurred.
Next, a case where a reverse turn occurs as shown in fig. 2C will be described. In the case of the reverse turn, the weft yarn Y reaches the position of the selvage yarn 54 before the second detection start time T2. Therefore, since the weft yarn Y is detected by the RH weft feeler 93 in the first weft detection range P1, the main control device 200 detects at least either the number of pulses of the detection signal equal to or greater than the preset first pulse threshold value S1 or the level signal value of the detection signal equal to or greater than the preset first level threshold value S3.
After the second detection start time T2, the weft yarn Y returns to the fabric 50 side and is therefore not detected by the RH weft detector 93. Therefore, in the second weft detection range P2, the weft yarn Y is not detected by the RH weft feeler 93, and therefore the main control device 200 detects the level signal value of the detection signal that is less than the preset second level threshold S4 together with the number of pulses of the detection signal that is less than the preset first pulse threshold S1.
That is, the main control device 200 determines that a reverse turn has occurred when the number of pulses of the detection signal is equal to or greater than the first pulse threshold S1 or the level signal value of the detection signal is equal to or greater than the first level threshold S3 in the first weft detection range P1, the number of pulses of the detection signal is less than the second pulse threshold S2 in the second weft detection range P2, and the level signal value of the detection signal is less than the second level threshold S4.
In this way, since the detection signals are pulse signals and level signals, and the first pulse threshold S1 and the second pulse threshold S2 are set according to the number of pulse signals and the value of the level signal, respectively, even when the weft yarn Y to be detected is a black yarn or a spun yarn, the weft yarn Y can be detected by using both the pulse signals and the level signals.
In embodiments 1 and 2 of the present invention, the RH weft detectors 91 and 93 and the W weft detector 92 are reflective optical sensors, but may be transmissive optical sensors in which the projection unit and the light receiving unit are arranged to face each other with the passing position of the weft yarn Y therebetween, and the light receiving unit receives light when the weft yarn Y is not present to detect the weft yarn Y.
In embodiments 1 and 2 of the present invention, the weft insertion condition is confirmed in the detection condition of the weft yarn Y in the first weft detection range P1 and the second weft detection range P2, but the state may be determined as the arrival delay of the weft yarn Y when the detection signal is less than the first pulse threshold value S1 in the first weft detection range P1 and the detection signal is equal to or greater than the second pulse threshold value S2 in the second weft detection range P2.
Claims (4)
1. A weft detecting method of an air jet loom, in which an optical weft detecting device for detecting a weft inserted and outputting a detection signal is provided between a warp at a position of a weaving end portion on the opposite side to a weft insertion side and a warp at a position of a selvedge,
a first weft detection range set after the weft insertion start time and before the weft insertion end time,
A second weft detection range set after a time when the weft is gripped by the warp at the position of the selvage in the first weft detection range,
A first threshold value which is a threshold value of the detection signal in the first weft detection range, and
a second threshold value that is a threshold value of the detection signal in the second weft detection range is set,
and determining that a reverse turn of the weft yarn has occurred when the detection signal is equal to or greater than the first threshold value in the first weft yarn detection range and is less than the second threshold value in the second weft yarn detection range.
2. The weft detecting method of an air jet loom according to claim 1,
the detection signal is a pulse signal, and the first threshold and the second threshold are set by the number of the pulse signals.
3. The weft detecting method of an air jet loom according to claim 1,
the detection signal is a pulse signal and a level signal, and the first threshold value and the second threshold value are set by the number of the pulse signals and the value of the level signal, respectively.
4. The weft detecting method for an air jet loom according to any one of claims 1 to 3,
and determining that a weft insertion error of the weft yarn has occurred when the detection signal is less than the first threshold value in the first weft detection range and less than the second threshold value in the second weft detection range.
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| JP2017-239729 | 2017-12-14 | ||
| JP2017239729A JP6922714B2 (en) | 2017-12-14 | 2017-12-14 | Weft detection method for air jet looms |
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| JPS59187647A (en) * | 1983-04-01 | 1984-10-24 | 津田駒工業株式会社 | Weft yarn defect detecting and stopping apparatus of loom |
| JP4151097B2 (en) | 1997-12-25 | 2008-09-17 | 津田駒工業株式会社 | Weaving feeler of loom |
| JP2003113555A (en) * | 2001-10-05 | 2003-04-18 | Tsudakoma Corp | Method and apparatus for detecting abnormality in shuttleless loom |
| JP6372229B2 (en) * | 2014-08-04 | 2018-08-15 | 株式会社豊田自動織機 | Weft detection device in jet loom |
| JP6566756B2 (en) * | 2015-07-15 | 2019-08-28 | 株式会社豊田自動織機 | Weft detection device for loom |
| JP6384453B2 (en) * | 2015-11-03 | 2018-09-05 | 株式会社豊田自動織機 | Weft detection method in air jet loom |
| CN107043986B (en) * | 2017-05-17 | 2018-09-07 | 杭州汇坤控制技术有限公司 | A kind of digital weft detecting method and system |
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| JP6922714B2 (en) | 2021-08-18 |
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| JP2019105013A (en) | 2019-06-27 |
| EP3498901A1 (en) | 2019-06-19 |
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