Process and device for detecting structural faults of moving flat textile materials

A process for on-line detection of structural faults in moving flat textile materials by means of a fixed spade-shaped leaf spring contact sensor, said process comprising the steps of:

• a) providing a spade-shaped leaf spring contact sensor (2) having a length of from 5 to 20 cm and a free end and providing a vibration pickup (4) for measuring motions of the spade-shaped leaf spring contact sensor (2);
• b) urging said free end of the spade-shaped leaf spring contact sensor (2) into engagement with a portion of a flat textile material (1) including threads arranged next to each other and extending in a thread direction;
• c) orienting said spade-shaped leaf spring contact sensor at a positioning angle .alpha. of from 10 to 60.degree. to said portion of the flat textile material (1);
• d) moving said portion of said flat textile material (1) including said threads relative to said spade-shaped leaf spring contact sensor during the urging and the orienting of steps b) and c) to cause motions of said space-shaped leaf spring contact sensor including regular deflections of said spade-shaped leaf spring contact sensor due to said threads and irregular deflections of the spade-shaped leaf spring contact sensor due to the structural faults of the textile material;
• e) continuously measuring said motions of the spade-shaped leaf spring contact sensor (2) including the regular deflections and the irregular deflections by means of the vibration pickup (4);
• e) permanently recording said motions of the spade-shaped leaf spring contact sensor (2) measured by means of the vibration pickup (4);
• and
• f) automatically analyzing the motions of the spade-shaped leaf spring contact sensor (2) measured by means of the vibration pickup (4) in order to detect the structural faults.