Shutter device
There is provided a shutter device which is used in a camera having two image-capturing optical systems and enables a significant reduction in the number of components. Two shutter openings are formed in a shutter base. Shutter blades and a diaphragm plate are provided forward of the shutter base. When a cam pin is reciprocally moved from the position of a start point to an intermediate position or from the intermediate position to the position of an end point, the shutter blades open and close a shutter one or more times. When the cam pin is located at any position along the way from the start position to the intermediate position, the diaphragm plate is moved to a location where small diaphragm openings correspond to the shutter openings. When the cam pin is located at any position along the way from the intermediate position to the position of the endpoint, the diaphragm plate is moved to a location where open diaphragm openings correspond to the shutter openings.
1. A shutter device used in a camera having two image-capturing optical systems, the device comprising:
a shutter base having formed therein two shutter openings corresponding to the two image-capturing optical systems;
a shutter member capable of simultaneously opening and closing the two shutter openings;
a diaphragm plate having two open diaphragm openings and two small diaphragm openings formed therein; and
a cam pin which can reciprocally travel, upon receipt of driving force from a single motor, along a travel path extending from the position of a start point to the position of an end point via an intermediate position, wherein
a shutter cam hole into which the cam pin is to be inserted is formed in the shutter member, and the shutter cam hole defines actuation of the shutter member so as to perform each of opening and closing actions one or more times when the cam pin is reciprocally moved from the start position to the intermediate position and from the intermediate position to the end position; and
a diaphragm cam hole into which the cam pin is to be inserted is formed in the diaphragm plate, and the diaphragm cam hole defines actuation of the diaphragm plate such that the two open diaphragm openings are located in front of corresponding shutter openings when the cam pin is located at any location from the start position to the intermediate position, and such that the two small diaphragm openings are located in front of corresponding shutter openings when the cam pin is located at any position from the intermediate position to the end position.
2. The shutter device according to claim 1 , wherein the shutter member has a pair of shutter blades which rotate to thus simultaneously open and close the two shutter openings; and
the shutter cam hole is formed in each of the shutter blades, and rotates the shutter blade in association with actuation of the cam pin.
3. The shutter device according to claim 1 , wherein, when the cam pin effects rectilinear translation,
the open diaphragm openings and the small diaphragm openings are formed, in the diaphragm plate, adjacent to each other in the direction of movement of the cam pin; and
the diaphragm cam hole is an elongated hole which extends in the direction of movement of the cam pin and is slightly shorter than a distance from the start position to the intermediate position or a distance from the intermediate position to the end position.
4. The shutter device according to claim 3 , wherein at least one of the two open diaphragm openings formed in the diaphragm plate is a cutout formed in an end portion of the diaphragm plate.
5. The shutter device according to claim 1 , further comprising:
a stop position regulatory member which hinders movement of the diaphragm plate upon engagement with a portion of the diaphragm plate and is disengaged from the diaphragm plate by means of elastic deformation upon exposure to an addition of given force or greater; and
the diaphragm plate has a section to be engaged which engages with the engagement member when the two open diaphragm openings have moved to positions corresponding to the two shutter openings and the two small diaphragm openings have moved to the positions corresponding to the two shutter openings.