US 5,337,110 A · Electromagnetic actuator

Abstract

An electromagnetic actuator that utilizes magnetic attractive and repulsive forces through the interaction of permanent magnetic and electromagnetic fields for moving an aperture/shutter blade or an aperture blade for setting the aperture for an exposure of an image through an imaging aperture. The actuator includes a base for supporting two permanent magnets which are arranged to rotate on a common axis in opposition to each other and under the influence of forward and reverse direction magnetic fields generated by an armature in response to respective forward and reverse direction currents. The first and second magnets are coupled to a blade at first and second pivot points, respectively, which pivot the blade from a stable rest position of said blade with respect to the imaging aperture to first and second aperture setting positions in response to prescribed rotation of the first and second magnets within defined limits. At least two aperture setting positions are provided by applying the forward and reverse drive current to the electromagnet coil in a mono-stable mode, whereby the blade moves to its rest position on removal of the drive current and where the blade operates as a shutter in the stable rest position.

Claims18

Dependent claims

An electromagnetically driven actuator supported by a base plate for controlling an aperture blade having at least first and second apertures formed therein for regulating the amount of light entering an imaging lens aperture comprising:

an electromagnetic armature and coil for providing a magnetic field of a forward polarity in response to a forward drive current and a magnetic field of a reverse polarity in response to a reverse drive current;
first and second permanent magnets;
means for supporting said first and second permanent magnets within the influence of their magnetic fields and the forward and reverse magnetic fields and for allowing rotational movement of said first and second magnets about a common axis under the collective influence of said magnetic fields;
and
means for coupling said first and second magnets to said blade to position said blade in a stable rest position in the absence of a forward or reverse magnetic field and for transferring rotational movement of said first and second magnets into movement of said blade between said stable rest position when no current is applied to said armature coil to a first aperture position when a forward drive current is applied to said armature coil, so that said blade may position said first aperture over said imaging lens aperture, and to a second aperture position when a reverse drive current is applied to said armature coil, so that said blade may position said second aperture over said imaging lens aperture.

2 more elements

A method of operating an electromagnetically driven actuator supported by a base plate for controlling an aperture blade having at least first and second apertures formed therein for regulating the amount of light entering an imaging lens aperture comprising the steps of:

providing a forward magnetic field of a forward polarity in response to a forward drive current and a reverse magnetic field of a reverse polarity in response to a reverse drive current;
supporting first and second permanent magnets within the influence of their respective magnetic fields and the forward and reverse magnetic fields of said electromagnetic armature and coil for allowing rotational movement of said first magnet and said second magnet about a common axis under the collective influence of said magnetic fields;
coupling said first and second magnets to said blade at first and second pivot points, respectively;
transferring rotational movement of said first magnet in response to a forward magnetic field into pivotal movement of said blade about said second pivot point, whereby said blade is movable between a stable rest position when no current is applied to said armature coil to a first position when a respective forward drive current is applied to said armature coil, so that said blade may position said first aperture over said imaging lens aperture;
and
transferring rotational movement of said second magnet in response to a reverse magnetic field into pivotal movement of said blade about said first pivot point, whereby said blade is movable between said stable rest position when no current is applied to said armature coil to a second position when a respective reverse drive current is applied to said armature coil, so that said blade may position said second aperture over said imaging lens aperture.

3 more elements

means for providing a forward magnetic field of a forward polarity in response to a forward drive current and a reverse magnetic field of a reverse polarity in response to a reverse drive current;
means for supporting first and second permanent magnets within the influence of their respective magnetic fields and the forward and reverse magnetic fields of said electromagnetic armature and coil for allowing rotational movement of said first magnet and said second magnet about a common axis under the collective influence of said magnetic fields;
means for coupling said first and second magnets to said blade at first and second pivot points, respectively and for moving from a stable rest position of said blade with respect to said imaging aperture in response to prescribed rotation of said first and second magnets;
means responsive to said forward magnetic field for allowing said first and second magnets to align to said forward magnetic field and pivot said blade to align a first aperture thereof with said imaging aperture;
and
means responsive to said reverse magnetic field for allowing said first and second magnets to align to said reverse magnetic field and pivot said blade to align a second aperture thereof with said imaging aperture.

3 more elements

Dependencies are inferred from the claim text.

Electromagnetic actuator

Life of this patent

Electromagnetic actuator

Life of this patent

Abstract

Claims18