IRIS MECHANISM

• Main Author: YOSHIDA AKIYUKI
• Format: Patent
• Language: English; Japanese
• Published: 11.01.2018
• Subjects: ACCESSORIES THEREFOR; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USINGWAVES OTHER THAN OPTICAL WAVES; APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FORPROJECTING OR VIEWING THEM; CINEMATOGRAPHY; ELECTROGRAPHY; HOLOGRAPHY; PHOTOGRAPHY; PHYSICS

PROBLEM TO BE SOLVED: To solve the problem that, although the conventional iris mechanism slides a diaphragm blade by a connection hole of an arm pin and the diaphragm blade, such a mechanism may be reduced to about 1/√2 of a rotational torque, and likely cause a backrush weak in vibration for the vibration of the main body itself.SOLUTION: The present invention is based on a combination of a spur gear and a rack gear, and fixes the spur gear on a compact motor shaft, and provides the rack gear on a diaphragm blade. The engagement between the spur gear and the rack gear converts a rotational movement into a linear movement, and a force is applied to the opposing gears by a torsion spring that attaches opposing rack gears to a bearing of the main body, thereby strengthening the engagement with the spur gear. This realizes an iris mechanism strong to the backrush and the vibration. 【課題】従来のアイリス機構はモーター軸に固着した、アームピンと絞り羽根の連結孔により、絞り羽根をスライドさせる機構であるが、それでは回転トルクの約1/√2に減少する損失がある、また、本体自身の振動に対し振動に弱い、バックラッシュを起こし易いと言う課題があった。【解決手段】本発明は平歯車とラックギヤの組み合わせを基本とするもので、小型モーター軸に平歯車を固着し、絞り羽根にラックギヤを設け、平歯車とラックギヤとの噛み合わせにより回転運動を直線運動に変換するもので、更に、相対するラックギヤを本体の軸受けに取り付けた、ねじりバネで相対するラックギヤに力を掛け、平歯車との噛合せを強固なものとする事で、バックラッシュ及び振動に強いアイリス機構を実現する。