Electromagnetic drive for a focal-plane shutter
AssigneeRollei Fototechnic GmbH
InventorBodo Mielke
Life of this patent
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Abstract
An electromagnetic drive for a focal-plane shutter of a camera having two light-excluding shutter curtains, each of the two shutter curtains being having its own electric drive motor, which is a linear motor constructed from permanent magnets and electromagnetic coils. The linear motor has at least two mutually aligned permanent magnets. The opposite pole faces of the magnets have the same polarity. A soft-magnetic disk is disposed between the permanent magnets. A soft-iron casing encloses the magnets and the soft-magnetic disk with an annular gap therebetween. A coil former is displaceably mounted in the annular gap such that it can exert an operating stroke between two stops. The coil former has a drive element for transferring the axial displacement of the coil former to the assigned shutter curtain.
Claims15
An electromagnetic drive of a focal-plane shutter of a camera having two light-excluding shutter curtains, each assigned its own linear motor, each linear motor comprising:
- a soft-iron casing;
- first and second mutually aligned permanent magnets housed in the soft-iron casing, wherein a magnetic pole of the first magnet and an opposite lying pole of the second magnet have the same polarity;
- a soft-magnetic disk disposed between the first and second permanent magnets;
- an annular gap defined between outer surfaces of the permanent magnets and the magnetic disk and an inner surface of the soft-iron casing;
- a coil former, including a coil winding, axially displaceable mounted in the annular gap to exert an operating stroke between two stops, wherein the coil former extends at least partially over the soft-magnetic disk;
- and
- a drive element provided on the coil former that transfers the axial displacement of the coil former to an assigned shutter curtain, said drive element protruding outward through an adopted slot opening provided in the soft-iron casing.
A linear motor for an electromagnetic drive of a focal-plane shutter of a camera, the linear motor comprising:
- a soft-iron casing;
- first and second mutually aligned permanent magnets housed in the soft-iron casing, wherein a magnetic pole of the first magnet and an opposite lying pole of the second magnet have the same polarity;
- a soft-magnetic disk disposed between the first and second permanent magnets;
- an annular gap defined between outer surfaces of the permanent magnets and the magnetic disk and an inner surface of the soft-iron casing;
- a coil former, including a coil winding, axially displaceable mounted in the annular gap to exert an operating stroke between two stops, wherein the coil former extends at least partially over the soft-magnetic disk;
- and
- a drive element provided on the coil former that transfers the axial displacement of the coil former to an assigned shutter curtain, said drive element protruding outward through an adopted slot opening provided in the soft-iron casing.
An electromagnetic drive of a focal-plane shutter of a camera having two light-excluding shutter curtains, each assigned its own linear motor, each linear motor comprising:
- a soft-iron casing;
- first and second mutually aligned permanent magnets housed in the soft-iron casing, wherein a magnetic pole of the first magnet and an opposite lying pole of the second magnet have the same polarity;
- a soft-magnetic disk disposed between the first and second permanent magnets;
- an annular gap defined between outer surfaces of the permanent magnets and the magnetic disk and an inner surface of the soft-iron casing;
- a coil former, including a coil winding, axially displaceable mounted in the annular gap to exert an operating stroke between two stops, wherein the coil former extends at least partially over the soft-magnetic disk;
- and
- a drive element provided on the coil former that transfers the axial displacement of the coil former to an assigned shutter curtain, wherein the two linear motors for the two shutter curtains are enclosed axially in line with one another by a common soft-iron casing.
Dependencies are inferred from the claim text.