Claims
- 1. Fault detection apparatus for material webs comprising: a light scanning device for directing a bead of light along an imaginary line on the surface of a web to effect line scanning thereof, said web having a width; and an elongate light receiving device disposed to receive light leaving said line within a reception plane containing said line and said light receiving device; said light receiving device comprising: a linear array of individual light receivers, means for selectively switching said light receivers on or off in dependence on the position of said light bead along said line and for switching off at least one of said light receivers at each particular instant, said light receivers generating signals in response to incident light, and means connecting said receivers to a processing circuit for processing said signals.
- 2. Apparatus in accordance with claim 1, wherein said switching means comprises an electronic switching device for switching on or off said light receivers cyclically and individually, said switching device being controlled by said scanning device for generating the scanning light beam in such a way that received light beams extending within a predetermined angular range in the reception plane fall on switched off light receivers while received light beams lying outside of the angular range fall on switched on light receivers.
- 3. Apparatus in accordance with claim 1, wherein said switching means comprises an electronic switching device for switching on or off said light receivers cyclically and in groups, said switching device being controlled by said scanning device for generating the scanning light beam in such a way that received light beams extending within a predetermined angular range in the reception plane fall on switched off light receivers while received light beams lying outside of the angular range fall on switched on light receivers.
- 4. Apparatus in accordance with claim 2, wherein each light receiver comprises a photoelectric converter.
- 5. Apparatus in accordance with claim 3, wherein each light receiver comprises a photoelectric converter.
Priority Claims (1)
Number |
Date |
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Kind |
3006072 |
Feb 1980 |
DEX |
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Parent Case Info
This is a division of application Ser. No. 235,694, filed Feb. 18, 1981, now U.S. Pat. No. 4,450,359, issued May 22, 1984.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4093866 |
Kasdan et al. |
Jun 1978 |
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4248537 |
Sick |
Feb 1981 |
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Divisions (1)
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Number |
Date |
Country |
Parent |
235694 |
Feb 1981 |
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