| 摘要 |
In a web break detecting device for web processing machines, more particularly web fed rotary printing presses, comprising at least one sensing means adapted for cooperation with the web and preferable in the form of a single path photoelectric detector whose beam is normally interrupted by the web and which is adapted to produce a signal if the position of the web should be displaced, in order to achieve a particularly high degree of reliability and very short response times, each sensing means, which is arranged adjacent to a longitudinal edge of the web, is provided with a deflecting means, by means of which a deflecting thrust may be produced permanently acting adjacent to the part of the associated longitudinal edge of the web, and which during normal operation is overridden by the web tension, such thrust causing the longitudinal edge of the web to moved out of the plane of the web during trouble-free operation, when the web tension fails, in relation to the sensing means.
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