| 摘要 |
The shutter comprises a first and a second blind (47, 48) extending in parallel planes close to each other and wound on at least one roller (6, 9) on each side of the exposure window, which blinds each have an edge (55, 56) which edges define a shutter slit (5) between them. The roller of the first blind is driven by a first pinion (7) which is rigidly coupled to a drive mechanism (31). In accordance with the invention the shutter comprises a second pinion (11) which is rotationally coupled to the first pinion, and a third pinion (14) which is coaxial with the second pinion and which is driven by the second pinion via an angular-positioning device (59) which drives the roller (9) of the second blind; the shutter also comprises tension means (49, 52, 53) which maintain each blind in its respective plane. In this way an accurately variable width of the shutter slit can be obtained. The shutter is used in cameras for aerial or marine surveillance.
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