JP2000292826A - Motor-driven shutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always set a diaphragm blade to a prescribed correct diaphragm value. SOLUTION: This motor-driven shutter is constituted as follows. By rotating a driving motor M so that a driving ring 3 is moved forward and backward, a diaphragm lever 8 is made to follow up a 1st cam 3b through a cam follower 10 and a closeout lever 11 is made to follow up a 2nd cam 3c through a cam follower 14. Then, a 1st spring 5 is locked to a diaphragm blade driving member 4. Besides, an open lever 21 is made to follow up a 3rd cam 3d through a cam follower 24. Then, a 2nd spring 17 is locked to an open blade driving member 16. The diaphragm blade 6 is constituted so that a lens aperture 20 is opened and closed by the movement of a diaphragm blade driving pin 6a. The open blade 18 is constituted so that the lens aperture 20 is opened and closed by the movement of an open blade driving pin 16a. The lever 11 is held by being attracted by a 1st electromagnet 15 and the lever 21 is held by being attracted by a 2nd electromagnet 23. Then, a signal for setting a diaphragm value is supplied to the motor M and the ring 3 is moved to a diaphragm position. Besides, the follower 10 is made to follow up the cam 3b and the driving member 4 is moved so that the blade 6 is set to the prescribed diaphragm value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera shutter, and more particularly to a motor-driven shutter in which the operation of a taking lens, the setting of an aperture value, and the exposure operation are performed by a single motor.

[0002]

2. Description of the Related Art As a conventional technique, for example, Japanese Unexamined Patent Publication No.
Japanese Patent Publication No. 138515 discloses that a single motor that rotates forward and backward operates an opening lever for opening and closing a shutter blade and a closing lever for opening and closing a diaphragm blade, and applies an urging force by a spring to each of these levers. Are shown, each of which is provided with electromagnet means for restraining the operation of the opening lever and the closing lever against the urging force. FIGS. 5 (a) and 5 (b) show a part of the closing lever of this configuration, and the closing lever a
Is swingably supported by a shaft b and has two arms c and d.
, And a counterclockwise rotational force is urged by a spring e. One arm c has a pin f that engages with an iron piece k that is attracted to a coil j of an electromagnet means i that restricts the operation of a closing lever a, and a pin that can slide on a throttle cam n of a drive ring m. h is provided. The other arm d branches into two branches, and a drive pin p for driving an aperture blade (not shown)
Is sandwiched. The drive ring m and the distance ring q are provided concentrically with the taking lens L.

As shown in a side view with a part broken away, the engagement between the iron piece k and the pin f is such that a notch r is provided on the iron piece k side, and the pin f is fitted into the notch r. A predetermined clearance g between the notch r and the pin f.
Is required. Then, the motor is rotated in the reverse direction, the opening lever (not shown) is rotated clockwise to drive the shutter blades to close the opening of the taking lens L, and the motor is rotated forward to set the taking lens L to the in-focus position. During normal rotation of the motor, the drive ring m rotates clockwise while the coil j is not energized, and the pin h follows the cam n to rotate the closing lever a counterclockwise. At the same time, the iron piece k moves through the pin f at the position facing the iron core of the electromagnet. The rotation of the closing lever a is transmitted to the aperture blade via the pin p, and the aperture blade is gradually closed from the open position.
The iron piece k is fixed at that position, and the closing lever a can no longer follow the rotation of the drive ring m, whereby the aperture blade completes setting the predetermined aperture value.

[0004]

In the operation of the above-described conventional arrangement, the left end of the pin f is set to the left end of the notch r as shown in the side view of FIG. When the coil j of the electromagnet device is energized in the state of contact with, the aperture value is set stably to a predetermined aperture value. But,
Generally, depending on the attitude of using the camera, a state in which the right end face of the pin f is in contact with the right end face of the notch r may occur, and in this state, a situation may occur in which the coil j is energized. in this case,
After the coil j is energized and the aperture is set, the closing lever a swings counterclockwise by the clearance g under the spring force of the spring e, and the left end face of the pin f becomes the left end face of the notch r. It will be stable in contact with. Therefore, there is a problem that the aperture value is finally different from the set correct aperture value and is stabilized, so that beautiful photographing cannot be performed.

[0005]

In order to solve the above-mentioned problems, the present invention provides a method of setting an aperture value by means of an aperture blade, wherein a signal for setting an aperture value is supplied to a drive motor, and a drive ring is moved to the aperture position. By moving the diaphragm follower to the first cam, the diaphragm follower moves the diaphragm blade driving member to set the diaphragm blade to a predetermined diaphragm value. Since the cam follower follows the first cam and sets the aperture value, the clearance is always shifted in a fixed direction due to the structure. Therefore, it is always possible to set the aperture value to a predetermined correct value. it can.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention includes a drive motor that rotates forward and backward and a drive ring that can reciprocate by the rotation of the drive motor. The drive ring is provided with first, second and third cams. The aperture blade driving member is the first
A first lever having a cam follower capable of following the second cam and a closing lever having a cam follower capable of following the second cam, and biasing the spring force in one direction.
Spring is hooked. The opening blade driving member has an opening lever provided with a cam follower capable of following the third cam, and a second spring for urging a spring force in the other direction is latched. An aperture blade that can open and close a lens opening by an aperture blade driving pin protruding from the aperture blade driving member, and an opening blade that can open and close the lens opening by an opening blade driving pin protruding from the opening blade driving member. It is provided. A first electromagnet capable of adsorbing and holding the closing lever and a second electromagnet capable of adsorbing and holding the opening lever are provided. When setting the aperture value by the aperture blade, a signal for the aperture value setting is supplied to the drive motor. Then, when the drive ring moves to the aperture position, the cam follower moves the aperture blade drive member following the first cam, and sets the aperture blade to a predetermined aperture value.

The setting of the exposure state is performed when the release lever is released by the release of the attraction by the second electromagnet.
The opening blade driving member is rapidly moved by the spring, and the opening blade instantaneously opens the lens opening to be in an exposed state. Further, the above-mentioned closing of the lens opening is performed by moving the diaphragm blade driving member when the attraction by the first electromagnet is released and the closing lever is opened after the exposure time has elapsed, and the diaphragm blade closes the lens opening. It is characterized by being.

[0008]

An embodiment will be described with reference to the drawings. The drawing shows the motor-driven shutter of the present invention in an unfolded state, with one set of three aperture blades 6 arranged at equal intervals around the lens opening 20 and one set of three aperture blades.
When the pair of opening blades 18 are overlapped with each other,
0 is located on the front surface. By the way, the drive ring 3 is drawn in a straight line because it is a development view, but it is actually a ring shape. In addition, although only one blade is shown in the drawings for the sake of simplicity, the opening / closing operation of one blade means the simultaneous opening / closing operation of a set of three blades. .

In FIG. 1, a shutter substrate (not shown) is provided with a drive motor M which is driven to rotate forward and backward, and the motor drives a motor pinion 1 and an idler 2 sequentially. The idler 2 is provided with a pinion 2 a, which meshes with a tooth 3 a of the drive ring 3. The drive ring 3 has a concentric ring shape with the lens opening 20 as a center, and is capable of reciprocating movement from a solid line position to a two-dot chain line position. A first cam 3b and a second cam 3b are provided on the side opposite to the side where the teeth 3a are formed.
c, the third cam 3d is formed so as to protrude.

At a position facing the first and second cams 3b and 3c, an arc-shaped diaphragm blade driving member 4 is provided by a first spring 5 to which a spring force is urged leftward. An aperture blade drive pin 4a is provided upright on the aperture blade drive member 4, and the lens opening 20 is fitted into a long groove 6a of the aperture blade 6 which can be freely opened and closed. The diaphragm blade 6 can swing about a rotation center axis 7. The aperture blade drive member 4 includes an aperture lever drive pin 4b
There is standing. The aperture lever 8 is provided so as to be swingable about a rotation center axis 9, and one arm of the aperture lever 8 is a fork portion 8a, and the aperture lever drive pin 4b is engaged with this fork portion. . The other arm 8b of the aperture lever 8 is provided with a pin-shaped cam follower 10, which receives the spring force of the first spring 5 to allow the first cam 3b
Can be hit by

The closing lever 11 is provided so as to be swingable about a rotation center shaft 12, a spring 13 is hooked on one arm 11a, and the closing lever 11 is biased by a counterclockwise spring force. is there. The other arm 11b is provided with a cam follower 14, which can elastically contact the second cam 3c under the spring force of the spring 13. The arm 11a has an iron piece 11c supported by a support portion 11d.
When the coil 15a is energized, the closing lever 11 is held by suction. The aperture blade driving member 4 includes a closing lever 11.
A pin 4c is provided upright to follow the swinging action of the spring 13 by the spring force of the spring 13 against the spring force of the first spring 5. The spring 5 only needs to cause the cam follower 10 to follow the cam 3b, so there is no need to increase the spring force, and the spring 5 is set to a sufficiently weak spring force as compared with the spring 13.

An arcuate open blade driving member 16 is provided at a position opposed to the third cam 3d so that a spring force is urged rightward by a second spring 17. Open blade drive member 16
An opening blade driving pin 16a is provided upright, and the lens opening 20 is fitted in a long groove 18a of the opening blade 18 which can be freely opened and closed. The opening blade 18 can swing about a rotation center axis 19. The opening lever 21 is provided so as to be swingable about a rotation center shaft 22. One arm is a fork portion 21a, and an opening lever driving pin 16b erected on the opening blade driving member 16 is provided on the fork portion. Engaged. One of the fork portions 21a extends, and the iron piece 21c
Are supported by the support portion 21d, and when the coil 23a of the electromagnet 23 is energized, the release lever 21 is attracted and held. The other arm 21b is provided with a cam follower 24, which receives the spring force of the second spring 17 and
It is possible to make contact with d.

Next, the operation will be described. At the beginning of the operation, as shown in FIG.
Are in a state in which the lens opening 20 is closed. The focus adjustment is the same as that of the related art, and the description is omitted. Next, in setting the aperture, when a drive signal for aperture setting is supplied to the drive motor M, the drive motor M starts, the motor pinion 1 rotates counterclockwise, and the pinion 2a of the idler 2 rotates clockwise. The drive ring 3 is moved to the left by a distance commensurate with the signal supplied to the motor M, as shown in FIG. At this time, the electromagnet 1
The coils 5, 23 are excited by the coils 15a, 23a and adsorb the iron pieces 11c, 21c.

Accordingly, the cam follower 10 follows the first cam 3b with the left movement of the drive ring 3, and the first cam 3b
The aperture lever 8 is rotated clockwise by lowering the inclined surface b to a position corresponding to the aperture. As a result, the aperture lever drive pin 4b moves leftward, and the aperture blade drive member 4
Moves leftward by the first spring 5. Since the diaphragm blade drive pin 4a moves to the left by this left movement, the diaphragm blade 6 rotates clockwise about the rotation center axis 7 and the lens aperture 20 is rotated.
Is moved to the open position by the set aperture amount. At this time, since the release lever 21 is in the attracted state to the electromagnet 23,
The opening blade driving member 16 remains in the state shown in FIG. 1, and the opening blade 18 remains at the position where the lens opening 20 is closed. Thus, the setting of the aperture value is completed as shown in FIG.

Next, when the electric signal to the electromagnet 23 is cut off, as shown in FIG. 3, the release lever 21 is released from the attraction to the electromagnet 23, and is rapidly opened by the spring force of the second spring 17. Since the driving member 16 moves to the right and the opening blade drive pin 16a moves to the right, the opening blade 18 rapidly rotates counterclockwise about the rotation center axis 19 and the lens aperture 20.
Fully open to expose. The opening blade driving member 16 is moved by a pin 25 projecting from a shutter substrate (not shown).
To stop rightward movement. Thus, the exposure state shown in FIG. 3 is obtained.

When the electric signal to the electromagnet 15 is cut off as shown in FIG. 4 when the time for obtaining the predetermined exposure amount elapses, the closing lever 11 is released from the attraction to the electromagnet 15 and the spring 13 is released. The closing lever 11 is rapidly rotated counterclockwise about the rotation center axis 12 by the spring force of (1), and moves the diaphragm blade driving member 4 rightward against the first spring 5 via the pin 4c. When the diaphragm blade drive pin 4a moves to the right due to this right movement, the diaphragm blade 6 rapidly rotates counterclockwise about the rotation center axis 7 to close the lens opening 20 and move to FIG.
State. The diaphragm blade driving member 4 stops rightward movement by contacting a pin 26 protruding from a shutter substrate (not shown).

Then, when the motor M is driven to rotate in the reverse direction and the pinion 2a of the idler 2 rotates counterclockwise via the motor pinion 1, the drive ring 3 is moved to the right, and at this time, the cam follower 24 of the opening lever 21 is moved to the third position. Cam 3
Following d, the release lever 21 is rotated clockwise. For this purpose, the opening blade drive member 16 is moved leftward against the second spring 17 via the release lever drive pin 16b.
Then, the opening blade driving pin 16a also moves to the left, so that the opening blade 18 rotates clockwise about the rotation center axis 19, closes the lens opening 20, and returns to the state of FIG. At the same time, the closing lever 11 rotates clockwise due to the right movement of the drive ring 3, the cam follower 14 elastically contacts the protrusion of the second cam 3c, and the cam follower 10 of the aperture lever 8 moves to the first cam 3b.
And returns to the state of FIG.

As described above, in the configuration of the present invention, when setting the aperture value, the cam follower 10 follows the first cam 3b and stops only at the aperture value setting position of the first cam 3b. Since the setting of the aperture value is completed, it is possible to easily and easily set the aperture value to the predetermined accurate value, and the attitude of using the camera is not affected at all. In the embodiment, the cam followers 10, 14, and 24 are pins formed integrally with the lever. However, the pins may be provided with a roller or the like to be rotatable. Further, the driving member is not limited to the ring-shaped one. Further, pins 25 and 26 are provided as stoppers for the aperture blade driving member 4 and the opening blade driving member 16, but if these pins are not provided, the cam follower 14 comes into contact with the cam 3c and the cam follower 24 comes into contact with the cam 3d. The blade driving member 4 and the opening blade driving member 16 may be stopped.

[0019]

According to the present invention, the aperture value is set by causing the cam follower to follow the first cam, so that the clearance is always shifted in a fixed direction because of the structure, so that the aperture value is affected by the attitude of using the camera. The aperture value can always be set to a predetermined correct value.

[Brief description of the drawings]

FIG. 1 is an exploded front view of a state at the start of an operation according to an embodiment of the present invention.

FIG. 2 is a developed front view of a state at the time of setting an aperture value in FIG. 1;

FIG. 3 is a developed front view in an exposed state of FIG. 1;

FIG. 4 is a developed front view of a state at the end of exposure in FIG. 1;

FIG. 5A is a front view of a main part illustrating a conventional configuration,
(B) is a partial side view.

[Explanation of symbols]

 M Drive motor 3 Drive member 3b First cam 3c Second cam 3d Third cam 4 Aperture blade drive member 5 First spring 6 Aperture blade 8 Aperture lever 10 Cam follower 11 Closing lever 14 Cam follower 15 First electromagnet 16 Opening blade drive member 17 Second spring 18 Opening blade 20 Lens opening 21 Opening lever 23 Second electromagnet 24 Cam follower

Claims (3)

[Claims] A drive motor that rotates forward and backward; a drive member that is reciprocally movable by rotation of the drive motor; first, second, and third cams provided on the drive member; A first spring having a cam follower capable of following the first cam and a closing lever having a cam follower capable of following the second cam, and biasing a spring force in one direction; An open blade having a latch blade driving member locked and a release lever having a cam follower capable of following the third cam, and a second spring for biasing a spring force in the other direction locked; A driving member, an aperture blade driven by the aperture blade driving member and capable of opening and closing the lens opening, an opening blade driven by the opening blade driving member and capable of opening and closing the lens opening, and capable of holding the closing lever by suction. No. And a second electromagnet capable of attracting and holding the opening lever. The setting of the aperture value by the aperture blade is performed by supplying a signal for setting an aperture value to the drive motor, and setting the drive ring A motor-driven shutter wherein the cam follower moves the diaphragm blade driving member following the first cam by moving to a diaphragm position, and sets the diaphragm blade to a predetermined diaphragm value. 2. The method according to claim 1, wherein the setting of the exposure state includes:
When the attraction by the second electromagnet is released and the release lever is released, the second spring rapidly moves the open blade driving member, and the open blade instantaneously opens the lens opening to expose the lens. A motor-driven shutter, characterized in that: 3. The lens opening according to claim 1 or 2, wherein the lens opening is closed when a predetermined time has elapsed and the first electromagnet is released and the closing lever is opened.
A motor-driven shutter, wherein the aperture blade driving member is moved so that the aperture blade closes a lens opening.