| 摘要 |
In a lens shutter having a polygonal diaphragm whose relatively large-area leaves are to be moved from an open position, which more or less releases the passage of light, at relatively high angular velocity into a closed position, it is possible for a sliding friction resistance, however small, to occur owing to the fact that the leaves slide off or slide along a cover disc assigned directly to them. In order to reduce the resistance delaying the closing movement to an insignificant and therefore negligible value, material is removed at points on the side of the cover disc facing the leaves to form narrow sliding webs which are matched to the concentric passage of light through the disc or to the arcuate path of movement of the rotatably mounted leaves.
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