| 摘要 |
PCT No. PCT/SE92/00677 Sec. 371 Date Apr. 5, 1994 Sec. 102(e) Date Apr. 5, 1994 PCT Filed Sep. 25, 1992 PCT Pub. No. WO93/06464 PCT Pub. Date Apr. 1, 1993.The present invention relates to an apparatus for optical monitoring of whether a thread is in motion or not in a determined direction in a region illuminated by one or more light sources, the region being a part, illuminated by the light source (5), of a channel (2) with light-reflecting walls (4, 6, 7, 10, 11, 12), through which the thread extends, and at least one light-sensitive element (8, 9) is placed in said part of the channel (2) in such a manner that the optical axes (13, 14, 15) of the light source (5) and the light-sensitive element (8, 9) make an angle with each other, whereby the optical coupling between the light source (5) and the light-sensitive element (8, 9) is influenced by the vibrations occurring in the thread during its motion, e.g. the microvibrations, the changes in the optical coupling being reflected in amplitude variations of a signal from the light-sensitive element (8, 9).
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