| 摘要 |
A yarn sensor for textile spinning and bobbin-winding machines for optically scanning a longitudinally traveling yarn ( 3 ) within a measurement gap ( 19 ), particularly for detecting extraneous fibers, includes a light source ( 20 ), a first receiver ( 23 ) for directly transmitted light, two further receivers ( 21, 22 ) for light reflected from the yarn ( 3 ), and light transmitting elements ( 24, 25, 26, 27 ) between the light source ( 20 ), measurement gap ( 19 ) and receivers ( 21, 22, 23 ). In the absence of the yarn ( 3 ), the receivers ( 21, 22 ) detect projected images of the opposite wall ( 62 ) of the measurement gap ( 19 ), located essentially outside both sides of the area of the wall ( 62 ) of the measurement gap ( 19 ) illuminated by the direct radiation of the light-emitting diode ( 20 ). As a result, parasitic signals are suppressed, improving the detection of extraneous fibers.
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