Weft Yarn Detection Method In Air Jet Loom

Abstract

The invention relates to a weft yarn detection method in an air-jet loom. Reduce false detections by photoelectric weft sensors. A first weft detection period P1 and a second weft detection period P2 are set in the photoelectric weft sensor. A first threshold (sensitivity) is set for the first weft detection period, and a second threshold (sensitivity) is set for the second weft detection period. The determination condition for the presence or absence of the weft yarn is set such that the number of pulse signals detected during the first weft yarn detection period is equal to or greater than a first threshold value (sensitivity), and that the number of pulse signals detected during the second weft yarn detection period is a second threshold value (sensitivity) In the above cases, it is determined that there is a weft yarn. The detection of the weft yarn Y can be reliably performed by a structure in which the detection of the weft yarn Y is performed in two stages, the first weft yarn detection period in which the first threshold value (sensitivity) is set and the second weft yarn detection period in which the second threshold value (sensitivity) is set. Distinguish weft yarn from warp yarn or waste selvedge yarn, reduce false detection by photoelectric weft yarn sensor.

Description

technical field [0001] The invention of the present application relates to a detection method of a weft yarn inserted into an air-jet loom. Background technique [0002] In the air-jet loom, a weft detection device for detecting whether the weft inserted has reached the weft end opposite to the weft insertion side at normal timing is provided at the weft end opposite to the weft insertion side. For example, Patent Document 1 discloses an air-jet loom in which a reflective weft yarn detection device equipped with a light-emitting element and a light-receiving element is installed between the warp yarn at the weaving end on the opposite side to the weft insertion side and the discarded selvedge yarn. invention. [0003] In the invention disclosed in Patent Document 1, in order to reduce the loss of the weft yarn due to the size of the weft yarn detection device in relation to the weaving direction, the ratio of the width of the protruding portion of the weft yarn detection de...

AI Technical Summary

Problems solved by technology

However, due to the difference in the thickness of the weft yarn supplied from the yarn feeding part, even when the weft yarn is inserted under the same weft insertion condition, the timing at which the weft yarn reaches the fabric end on the opposite side differs.

[0008] If there is a difference in the arrival timing of the weft yarn, the weft yarn that is normally inserted may not be detected when the end of the weft yarn detection period is advanced.

If the weft yarn that is normally inserted cannot be detected, it will be judged as poor weft insertion regardless of whether the weft insertion is normal, and the air jet loom will be stopped.

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