Electromagnetic trigger device for use with camera capable of automatic time exposure

An electromagnetic trigger device for use with a camera of the type capable of automatic time exposure comprising:

• a. a power supply;
• b. a motor;
• c. a trigger switch;
• d. shutter driving means driven by said motor for driving a shutter and movable between a fully closed position and a fully open position, said shutter driving means fully opening the shutter when it is at the fully open position and fully closing the shutter when it is at the fully closed position;
• e. engaging means movable between a latching position and a non-latching position, said engaging means being adapted, when moved to said latching position, to latch said shutter driving means which occupies the fully open or fully closed position;
• f. a motor switch which is closed for electrically connecting said motor to said power supply, when said engaging means is in said non-latching position;
• g. a starting coil for attracting said engaging means, when energized, to move said engaging means to said non-latching position;
• h. a switching circuit for connecting said starting coil to said power supply when turned on;
• i. a starting capacitor connected to said power supply so as to be charged when said trigger switch is opened and connected to said switching circuit to render said circuit conductive when said trigger switch is closed;
• j. reset means for rendering said switching circuit non-conductive for a predetermined period during an interval beginning with the closing operation of said trigger switch, said predetermined period being shorter than the shorter of the time interval required for said shutter driving means to move from the fully closed position to the fully open position and the time interval required for said driving means to move from the fully open position to the fully closed position;
• and
• k. a charging circuit interlocked with said shutter driving means for charging said starting capacitor connected to said switching circuit to thereby render said switching circuit conductive when said shutter driving means is in the fully open position, whereby conduction of the switching circuit by the charge of said starting capacitor through said charging circuit energizes said starting coil and then said motor to move the shutter driving means from the fully open position to the fully closed position.