Moving magnet type instrument
AssigneeNihon Beru-Haueru Kabushiki Kaisha (Bell & Howell Japan, Ltd.)
InventorSeiichi Satto
Life of this patent
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Abstract
For driving exposure control vanes in photographic equipment in response to ariations in the quantity of light, a moving magnet type instrument has a magnet which is positioned proximate a fixed field coil wound on a two piece frame. The magnet is formed as a unitary component of magnetic material and plastic material interlocked against separation, and is arranged for displacement in bearings in the frame proximate which a magnet biassing material is arranged to urge the magnet into a position whereby the supported vane is maintained at a relatively constant spacing with respect to a fixed camera component.
Claims7
Improvements in a moving magnet instrument in which a magnet member moves relative to a frame unit in response to variations in current flow through a coil fixed relative to the frame unit and relative to which the magnet member is rotatable arcuately in response to current flow variations through the coil, the improvement comprising:
- the frame unit being of two piece construction capable of assembly into a unit, each piece having a bearing alignable with the other bearing upon assembly of the respective pieces;
- the magnet member being formed with magnetic material and a plastic material interlocked to prevent separation of one material from the other, and
- having an axle portion located in said bearings formed in said frame unit thereby defining an axis about which said magnet member is rotatable in the magnetic field of the fixed coil
- whereby said magnet member is rotatable in response to current which flows through the coil.
Dependencies are inferred from the claim text.