| 摘要 |
PURPOSE:To provide a lens barrel having a focusing mechanism which is small in size, light in weight and low in cost by providing a spring mechanism which energizes and releases an energizing spring force to and from a focusing lens barrel cooperatively with rotation of a lens barrel for focus changing. CONSTITUTION:The energizing spring 9 is in the state of 9T shown in the figure where the spring does not engage to a cam face 4d in a long focus state (a change lens is held positioned on the optical axis for photographing). On the other hand, the spring 9 attains the state of 9W shown in the figure where the spring engages to the cam face 4d in the short focal state in which the change lens 1 is retreated off the optical axis of photographing. The backward energizing force acts on the focusing lens barrel 4 in this state. A shaft 4b provided as a part of the lens barrel 4 is freely fitted into a square hole 10d formed to a stopper plate 10. This shaft 4b is confined to the length l shown in the figure in the moving range by the hole 10d, by which the moving limit of the focusing lens 2 is controlled. The focusing mechanism which is small in size, light in weight and low in cost is thereby obtd.
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