| 摘要 |
<p>A camera is provided with an electromagnetic means for generating the desired mechanical movement for effecting cyclic displacement of a mechanical system, such as a mirror mechanism, shutter mechanism, etc., between two end positions. The electromagnetic means comprises an armature (100) arranged to pivot around an axis (108). The armature is connected to a rocker arm (105) which, in turn and in a known manner, transmits the rocking movement of the armature to a rotating movement of a plurality of shutter blades (200) via a linkage system (201, 202, 204, 205). A spring means (104) biases the system towards a neutral position or zone between the end positions. Drive means (102, 103) ensures that the system sequentially reaches the end positions and that the drive means is activated during, or during part of, the displacement of the system between the end positions. The drive means comprises permanent magnets (103), whose magnetic force field holds the armature in either of the two end positions, while completely counteracting the force of the biasing means, which force strives to return the armature to the neutral position, and at least one coil (102) which exerts a force on the armature, when a voltage is applied over the coil, which force is sufficiently large to overcome the magnetic force of the permanent magnets.</p> |
