| 摘要 |
PROBLEM TO BE SOLVED: To use the gear of the outer periphery of a rotary barrel in order to detect a zoom position. SOLUTION: As long as a zoom switch 10 does not reach a reference stop position in the case of rotating the rotary barrel 4, the interference part 11b of the movable switch piece 11 of the switch 10 runs onto the gear 6 of the barrel 4 and is separated from a fixed switch piece 12, so that the switch 10 is turned off. When the switch 10 reaches the reference stop position by rotating the barrel 4 further, the interference part 11b of the switch piece 11 falls in the non-tooth part 13 of the gear 6 of the barrel 4, where the gear 6 is omitted, by its elastic action, and the leading flat part 11 a thereof comes in contact with the switch piece 12 and the switch 10 is turned on. By providing the non- tooth part 13 on the gear 6 of the barrel 4, a small-sensitivity zoom position detecting mechanism utilizing the rotation of the barrel 4 is constituted even in the case of the lens barrel where the gear 6 is formed over the half or more of the periphery of the barrel 4. |
