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US 4,306,788 AGranted
Electromagnetically controlled shutter
AssigneeCanon Kabushiki Kaisha
InventorsYukio Ogawa, Michio Hirohata, Tetsuya Taguchi
Life of this patent
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Abstract
An electromagnetic actuating device for controlling the opening and closing operation of a shutter includes a plurality of plate-like permanent magnets and yokes alternating in layers to form a plurality of magnetic paths, and a moving coil arranged to be movable in a space provided in said magnetic paths. The device is thus minimized in bulk and size, can be built into the shutter casing, and rendered operable with electrical energy consumption kept to a minimum.
Claims4
An electromagnetically controlled shutter comprising:
- a plurality of shutter blades;
- a drive member for driving said shutter blades;
- a moving coil connected to said drive member;
- a plurality of flat plate-shaped permanent magnets;
- a plurality of flat plate-shaped yokes;
- and
- a power source;
- said yokes including one inner yoke and two outer yokes and being arranged to form a plurality of magnetic paths with said permanent magnets interposed between the inner and outer yokes at both end parts of the yokes in a sandwiched laminated manner with two spaces provided for accommodating the moving coil between the inner yoke and the outer yokes in the middle part of the yokes;
- said moving coil being provided with two flatly-shaped winding parts and being fitted on the outside of a rectangular portion of the inner yoke formed in the middle of the inner yoke;
- and said moving coil being arranged to linearly move within said spaces so as to cause said shutter blades to be opened or closed through said drive member when the moving coil is energized.
7 more elements
Dependencies are inferred from the claim text.