JP2518181B2 - Lens shutter - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens shutter of a camera, and more particularly to a lens shutter operating mechanism.

B. Conventional Technology Conventionally, a programmable lens shutter is known as a lens shutter for a camera. This is to adjust the exposure amount by closing the shutter blade at a timing according to the brightness of the subject during the opening operation of the shutter blade.

Among such program lens shutters, there is one called a fast-return method. This is the Japanese Examined Sho 48-6
As can be seen in the 971 publication and the Jitsukō Sho-58-29450 publication,
An opening / closing member having a closing habit of directly engaging with the shutter blade (the shutter blade is always biased in the closing direction),
A drive member for moving the opening / closing member in the opening direction is provided, and when the shutter is closed by the mechanism during the opening thereof, the transmission of the force from the driving member to the opening / closing member is released, and the opening / closing member is moved to the closed position by the habit of closing. I tried to go back.

C. Problems to be Solved by the Invention The conventional lens shutter described above has a problem that the reset mechanism after the opening and closing operation of the shutter blades becomes complicated, the number of parts increases, and the reliability of the shutter is low.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, and to provide a lens shutter that can simplify the structure of the shutter mechanism, reduce the number of parts, and improve the reliability of the shutter mechanism. .

D. Means for Solving the Problems The lens shutter of the present invention includes: a shutter blade (1, 2) that performs an exposure operation; and a shutter blade that moves in the positive direction to open the shutter blade, and moves in the opposite direction to move the shutter blade. A first member (5, 6) for closing the shutter blades, a first biasing means (7) for biasing the first member in the opposite direction, and the shutter blade so as to be stopped at a position where the shutter blade is fully closed. A restricting means (8) for restricting the movement of the first member, a second member (9, 11) that rotates in conjunction with the first member, and a rotatably supported shaft coaxially with the first member. An armature lever (1) that supports the rotating shaft of the second member and has an armature (13) at the other end.
2), an electromagnet device (14) for adsorbing the armature and holding the armature lever in the original position against the urging force of the first urging means, and a direction of the original position with respect to the electromagnet device. Second for urging the armature lever
When the biasing means (15) and the electromagnet device attract and hold the armature in the original position, the biasing means (15) moves in the first direction to move the first biasing means through the second member. A shutter drive means (16, 17) for moving the first member in the forward direction while accumulating an urging force, and when the armature is released from adsorption of the electromagnet device, it is accumulated when the shutter blade is opened. After the shutter blade is fully closed by moving the first member in the opposite direction by the urging force of the first urging means and the armature is released from the electromagnet device, the shutter driving means is operated by the first urging means. The armature lever is reset to the original position by the action of the second biasing means while the shutter blade is fully closed by moving in the second direction opposite to the direction. You.

E. Action In a state where the armature lever is attracted by the electromagnet device in its original position, the shutter blade opens by the movement of the shutter driving means in the first direction via the first and second members. When the attraction of the armature lever by the electromagnet device is released, the shutter blades are fully closed by the first urging means. Then, as the shutter driving means moves in the second direction, the lens shutter is reset by returning the armature lever to the original position by the second biasing means while keeping the shutter blade fully closed.

Therefore, in the present invention, the resetting of the lens shutter can be performed only by returning the armature lever to its original position by the second biasing means, and accordingly, the lens shutter having a simple structure and high reliability. It will be possible to obtain.

F. Embodiment One embodiment of the present invention will be described in detail with reference to FIGS.

FIG. 1 is a perspective view of the entire lens shutter.
4 to 4 are front views showing the operating state.

In the figure, a pair of shutter blades 1 and 2 that perform an exposure operation
Are arranged so that their parts overlap each other when fully closed, and one ends of the shutter blades 1 and 2 are rotatably supported by respective shafts 3 and 4 which are parallel to each other.

The fan-shaped first gear member 5 is rotatably attached to the shaft 3, and opens and closes the shutter blades 1 and 2 to form an exposure opening around the optical axis L. The tip of the pin 6 projecting at a right angle to the tooth side surface of the first gear member 5 has elongated holes 1a and 2a formed on the pivotal support side of the shutter blades 1 and 2 (the elongated hole 2a is shown for the sake of the drawing). Is not fitted). Further, a spring 7 that biases the shutter blades 1 and 2 in the closing direction is connected to the tooth portion side of the first gear member 5, and the first gear member 5 is further connected.
A projecting piece 5a projecting from the pivotal support base in the direction opposite to the tooth portion abuts on the stopper 8 to restrict the clockwise rotation of the first gear member 5 to bring the shutter blades 1 and 2 to the fully closed position. Hold.

The fan-shaped second gear member 9 meshing with the first gear member 5 is a shaft.
It is rotatably supported by 10. One end of an operation pin 11 is fixed in parallel with the shaft 10 to a projecting piece 9a projecting from the pivotal base portion of the second gear member 9 in the direction opposite to the tooth portion.

Shaft 1 of second gear member 9 for opening and closing shutter blades 1 and 2
0 is supported at one end of the armature lever 12, and a substantially middle portion of the armature lever 12 is pivotally attached to the shaft 3 while the other end thereof has an armature 13
Is fixed, and the armature 13 faces the electromagnet device 14 that attracts the armature 13. Further, a reset spring 15 is connected to the other end of the armature lever 12 to urge the armature 13 in a counterclockwise direction so as to bring the armature 13 into contact with the electromagnet device 14.

The drive ring 16 is for operating the shutter blades 1 and 2 in the opening direction and is rotatably arranged around the optical axis L, and a gear portion 16a is formed on a part of its outer peripheral edge. ing. Further, a cam 16b that engages with the operation pin 11 of the second gear member 9 is formed adjacent to one end of the gear portion 16a,
A gear 17 rotated by a drive source (not shown) is meshed with the gear portion 16a.

Next, the operation of the present embodiment configured as described above will be described.

FIG. 2 shows a reset state in which the first and second gear members 5 and 9 and the armature lever 12 fully close the shutter blades 1 and 2. From this state, for example, the electromagnet device 14 is energized to excite the armature 13 by exciting it, and then the gear 17 is rotated in the direction of arrow A in FIG. 2 to rotate the drive ring 16 in the counterclockwise direction. . Then, as the drive ring 16 rotates, the cam 16b causes the operation pin 1 of the second gear member 9 to move.
1, the operation pin 11 is pushed in the direction away from the optical axis L along the inclined surface 16b ₁ of the cam 16b. At this time, since the armature 13 is attracted to the electromagnet device 14, the armature lever 12 does not move, and the second gear member 9 rotates clockwise about the shaft 10. Along with this, the first gear member 5 meshing with the second gear member 9 rotates counterclockwise around the shaft 3 against the biasing force of the spring 7. At this time, the pin 6 integrated with the first gear member 5 moves counterclockwise to rotate the shutter blades 1 and 2 in the directions of arrows B and C in FIG. 1 about the shafts 3 and 4, respectively. The shutter blades 1 and 2 are moved in the opening direction. Then, the flat surface 16b ₂ connected to the end of the inclined surface 16b ₁ is the operation pin.
When engaged with 11, the shutter blades 1 and 2 are fully opened.

The opening operation speed of the shutter blades 1 and 2 at this time is set by the inclination angle of the inclined surface 16b ₁ and the rotation speed of the drive ring 16.

While the first gear member 5 is rotating in the counterclockwise direction, the spring 7 presses the operating pin 11 against the inclined surface 16b ₁ or the flat surface 16b ₂ of the cam 16b, so that the armature lever acts as a reaction force. 12 receives a force to rotate it in the clockwise direction, but the rotation is blocked by the attraction of the armature 13 to the electromagnet device 14.

FIG. 3 shows a state in which the drive ring 16 rotates counterclockwise to reach the final end, the flat surface 16b ₂ of the cam 16b engages with the operation pin 11, and the shutter blades 1 and 2 are fully opened.

In such a state, when the power supply to the electromagnet device 14 is stopped, the attraction force to the armature 13 disappears, so that the armature lever 12 moves in the clockwise direction about the axis 3 by the tension spring force of the spring 7 as shown in FIG. At the same time when the first gear member 5 is rotated in the clockwise direction about the shaft 3, the protruding piece 5a comes into contact with the stopper 8
The clockwise rotation of the gear member 5 is stopped, and the shutter blades 1 and 2 are fully closed at this position.

A reset spring 15 is hooked on the armature lever 12, and the counterclockwise moment of the armature lever 12 caused by the reset spring 15 is generated by the spring 7.
Since it is set to be much weaker than the moment in the clockwise direction received by the armature lever 12, the closing operation of the shutter is not hindered.

The above description is for the case where the shutter blades 1 and 2 are closed after they are fully opened, but the electromagnet device is in the middle of opening, that is, when the intermediate portion of the inclined surface 16b ₁ of the cam 16b is engaged with the operation pin 11. When the power supply to 14 is stopped, the shutter blades 1 and 2 start to close from that position, and the exposure amount can be adjusted in a programmable manner.

When the drive ring 16 is rotated clockwise by the gear 17 from the state shown in FIG. 4, the armature lever 12 is returned (reset) to the original position shown in FIG. 2 only by the spring force of the reset spring 15. , The armature 13 is pressed by the electromagnet device 14. Therefore, the above-described operation can be started after the electromagnet device 14 is energized to attract the armature 13 at a predetermined timing of the imaging sequence. Even when the shutter blades 1 and 2 enter the closing operation before being fully opened, the drive ring 16 can be rotated clockwise to return to the state shown in FIG.

The shutter opening / closing drive means for rotating the second gear member 9 in the direction in which the shutter blades 1 and 2 are opened is not limited to the one using the rotating drive ring 16 as in the above-described embodiment, and the operation pin is provided by a cam. A member that moves linearly may be used as long as it can push 11. Alternatively, the electromagnet device 14 may be of a combination type so that the armature is released when the electromagnet is energized and the armature is attracted when the energization is cut off.

In the configuration of the above embodiment and the configuration of the claims, the first
The gear member 5 and the pin 6 correspond to the first member, the stopper 8 corresponds to the restricting means, the second gear member 9 and the operating pin 11 correspond to the second member, and the drive ring 16 and the gear 17 correspond to the shutter driving means.

G. Effect of the Invention As described above, according to the present invention, the driving force from the shutter driving means drives the first and second members to open the shutter blades, and the biasing force of the first biasing means causes the shutter blades to move. After the shutter is fully closed, the shutter is reset only by returning the armature lever to the original position by the second biasing means such as the spring in accordance with the operation of returning the shutter driving means to the original position. The shutter reset mechanism is simplified, the number of components is reduced, the cost can be reduced, and the reliability of the shutter can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a lens shutter according to the present invention. FIG. 2 is a front view of the shutter opening / closing mechanism before the operation in this embodiment. FIG. 3 is a front view of the shutter opening / closing mechanism in the shutter blade opening operation state in the present embodiment. FIG. 4 is a front view of the shutter opening / closing mechanism showing the operating state immediately after the shutter blade is closed (before reset) in this embodiment. 1,2: Shutter blade 3.4: Shaft 5: First gear member 6: Pin 7: Spring 8: Stopper 9: Second gear member 10: Shaft 11: Operation pin 12: Armature lever 13: Armature 14: Electromagnet device 15 : Reset spring 16: Drive ring 17: Gear 16a: Gear part 16b: Cam 17: Gear

Claims (1)

(57) [Claims] 1. A shutter blade (1, 2) for performing an exposure operation, and a first member (5, 6) that moves in the forward direction to open the shutter blade and moves in the opposite direction to close the shutter blade. )
A first urging means (7) for urging the first member in the opposite direction, and the first urging means so as to stop at a position where the shutter blade is fully closed.
A restricting means (8) for restricting the movement of the member, a second member (9, 11) which rotates in conjunction with the first member, and a rotatably supported coaxially with the first member, the one end of which is An armature lever (12) that supports the rotating shaft of the second member and has an armature (13) at the other end, and the armature that attracts the armature against the urging force of the first urging means. An electromagnet device (14) for holding the lever in the original position, a second urging means (15) for urging the armature lever in the direction of the original position with respect to the electromagnet device, and the electromagnet device for applying the armature. By moving in the first direction while sucking and holding in the original position,
Shutter driving means (16, 17) for moving the first member in the forward direction while accumulating the urging force of the first urging means via the second member, and the armature is attracted to the electromagnet device. When the shutter blade is opened, the first member is moved in the opposite direction by the urging force of the first urging means accumulated when the shutter blade is opened, the shutter blade is fully closed, and the armature is the electromagnet device. After the shutter blade is released from the second direction, the shutter driving means moves in the second direction opposite to the first direction, so that the shutter blade remains fully closed.
A lens shutter characterized in that the armature lever is reset to the original position by the action of a biasing means.