Patent ID: 6068028
Filing Date: 2000-05-30
Classification: D03D

Abstract:
A method of scanning a yarn of predetermined length which is intermittently withdrawn during insertion cycles of a weaving machine from a winding reservoir provided on a storage drum of a weft-yarn feeding device, said weft-yarn feeding device including a withdrawal sensor which produces yarn pulses wherein at least one said yarn pulse is produced during passage of the yarn within one insertion cycle, said withdrawal sensor further producing interference pulses due to passing particles including dirt, said weft-yarn feeding device including a circuit wherein a winding signal is derived respectively from said yarn pulse and is transmitted to a signal-processing device, the method comprising the steps of:providing a band-pass filter assembly in said circuit which said band-pass filter assembly has a yarn pulse acceptance which permits acceptance of said yarn pulses which are relatively slow and weak;accepting at least a first one of said yarn pulses with said band-pass filter assembly; andchanging said yarn pulse acceptance of said band-pass filter assembly with an increasing yarn speed and/or upon generation of at least a first said winding signal which corresponds to said first yarn pulse; andsaid yarn pulse acceptance after said changing permitting acceptance by said band-pass filter assembly of further said yarn pulses which are relatively fast and strong and preventing acceptance of said interference pulses which are relatively slower or weaker in comparison with said further yarn pulses to suppress false winding signals caused by said interference pulses.