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US 4,881,093 AGranted
Electromagnetic shutter apparatus
AssigneeEastman Kodak Company
InventorDavid R. Dowe
Life of this patent
Estimating the term…
Abstract
An electromagnetically operated shutter assembly for a camera includes permanent magnets which are affixed to shutter blades. An electromagnetic field is generated by a number of armatures which interact with the permanent magnets to cause the shutter blades to move between open and closed positions. The configurations of the permanent magnets and armatures permit the blades to be held in the open and closed positions without the further application of current to the armatures. The permanent magnets are "levitated" by the electromagnetic field in order to facilitate movement of the shutter blades between the opening and closing positions.
Claims8
A shutter apparatus comprising:
- a. support means having an opening;
- b. a plurality of shutter blades which are attached to the support means for movement about a main axis between a first position in which the blades cover a greater amount of the opening, and a second position in which the blades cover a lesser amount of the opening;
- c. a plurality of permanent magnets which are respectively attached to the blades in a manner that the mass of the magnets are generally centered about the main axis;
- d. a plurality of means, attached to the support means, for generating an electromagnetic field which interacts with the permanent magnets so as to cause movement of the magnets in a manner that the blades move between their first positions and their second positions;
- and
- e. means for synchronizing the shutter blades and the means for generating an electromagnetic field in a manner to maintain equal rates of movement of the blades.
3 more elements
A shutter apparatus comprising:
- a. support means having a first member , the first member having an opening;
- b. a plurality of shutter blades which are attached to the support means for movement about a main axis between a first position in which the blades cover a greater amount of the opening, and a second position in which the blades cover a lesser amount of the opening;
- c. a plurality of permanent magnets which are respectively attached to the blades;
- d. means, attached to the support means, for generating an electromagnetic field which interacts with the permanent magnets so as to cause movement of the magnets in a manner that the blades move between their first positions and their second positions, and the field generating means further includes a plurality of electromagnetic means which are positioned away from the first member in a manner to urge the magnets away from the first member by means of a magnetic attraction between the electromagnetic means and the magnets;
- and
- e. means for synchronizing the shutter blades and the means for generating an electromagnetic field in a manner to maintain equal rates of movement of the blades.
3 more elements
A shutter apparatus comprising:
- a. support means having an opening;
- b. a plurality of shutter blades which are attached to the support means for movement between a first position and a second position in which the blades cover different amounts of the opening;
- c. a plurality of permanent magnets which are respectively attached to the blades and which have a first portion having a first magnetic pole, and a second portion having a second magnetic pole which is opposite to the first magnetic pole;
- d. means, attached to the support means, for generating an electromagnetic field so as to cause movement of the magnetic means in a manner that the blades move between their first positions and their second positions, the field generating means further including i) a plurality of electromagnetic means which are located so as to magnetically interact with the magnets and which have a first portion and a second portion, ii) means for inducing a first magnetic polarity in the electromagnetic means such that the first position has the first magnetic pole and in a manner that when the second portion of the magnetic means is closer that the first portion of the magnets to the first portion of the electromagnetic means and the second portion of the magnets have opposite magnetic polarities in order to urge the magnets to the first position, and iii) means for inducing a second magnetic polarity in the electromagnetic means such that the first portion of the electromagnetic means has the second magnetic pole in a manner that when the first portion of the magnets is closer that the second portion of the magnets to the first portion of the electromagnetic means then the first portion of the electromagnetic means and the first portion of the magnets have opposite magnetic polarities in order to urge the magnets to the second position;
- and
- e. means for synchronizing the shutter blades and the means for generating an electromagnetic field in a manner to maintain equal rates of movement of the blades.
3 more elements
Dependencies are inferred from the claim text.