| 摘要 |
A closure mechanism, such as a shutter in a camera, includes a closure member having an arcuate portion arranged to roll on a support member to cause a part of the closure member to move across an aperture thereby providing a movable barrier permitting selective communication of the aperture with spaces on opposite sides of the closure member. When used in a camera, the closure member is accommodated in an enclosure of which one wall includes the aperture, which may be a fibre optic plate. The closure member is movable between two extreme positions; in one position a mirror carried by the closure member optically couples the aperture with a viewing system and in the other position it blocks the viewing system while a film is located adjacent the aperture by a mechanism actuated in synchronism with the closure member.
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