METHOD FOR DETECTING FRAME WIRE AND FRAME WIRE DETECTION UNIT IN AN AIR JET TYPE WEAVING

摘要

A weft yarn detection unit is used in an air jet type loom including a main nozzle, secondary nozzles, and a weft brake. The air jet loom inserts a weft yarn using air jets emanating from the main nozzle and the secondary nozzles. The weft detection unit also includes a sensor which is placed in a position which precedes the position reached by the leading end of the weft yarn at the moment corresponding to the braking of the weft brake, a means of calculation which calculates the mean square deviation of the moments corresponding to the fact that the front end of the weft reaches a median position detected by the sensor, and a warning output means that sends a warning when the mean square deviation exceeds a threshold.