JP2574695Y2 - Shutter drive mechanism that doubles as lens drive mechanism - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shutter drive mechanism that also serves as a lens drive mechanism, and more particularly, to a step motor having a single step motor as a drive source for driving a lens mechanism and a shutter mechanism. The present invention relates to a shutter driving mechanism that also serves as a lens driving mechanism capable of reducing a load.

[0002]

2. Description of the Related Art A mechanism for driving a lens mechanism and a shutter mechanism by using a single step motor as a drive source has been known. Generally, in this type of mechanism, a lens drive is performed by rotation of a step motor. The mechanism is advanced to a target in-focus position, and after positioning the lens drive mechanism by, for example, a ratchet mechanism, the step motor is reversed to release the shutter mechanism, and thereafter returns to the initial position.

FIG. 8 shows a preferred example of a conventional mechanism of this kind. The structure and operation of the mechanism will be described. When the output pinion 2 of the step motor 1 rotates counterclockwise, the rotation of the output pinion 2 is controlled by a two-stage gear 3 and a ring-shaped. The drive member 4 is transmitted to the drive member 4 via a rack 4a formed on the outer edge of the drive member 4, and the drive member 4 is turned left. During the leftward turning process of the driving member 4, the pin 4 b implanted in the driving member 4 becomes a ring-shaped lens driving member 5.
Is engaged, and the lens driving member 5 is driven to rotate leftward. 120 ° on the side of the subject of the lens driving member 5
Three convex cams 5b are formed at intervals, and inclined cam edges respectively supported by the convex cams 5b are formed on the lens barrel (not shown) at 120 ° intervals. The lens barrel (not shown) is extended.

When the lens driving member 5 is turned counterclockwise to a target in-focus position, the output pinion 2 is reversed and the driving member 4 is turned clockwise. At this time, the ratchet gear 5c is pivotally supported on the shaft 7 by the ratchet gear 5c. The ratchet lever 6 is engaged with the click 6a and remains at the in-focus position. Reference numeral 8 denotes an opening / closing lever pivotally supported by a shaft 9 and provided with a right turning force by a spring 10. A pin 8a formed on the back surface of the opening / closing lever 8 is engaged with a shutter blade (not shown). are, open closed
Shutter blades, not shown when the lever 8 is right- is open operates.

As described above, the tilt cam 8b formed on the opening / closing lever 8 is formed on the outer edge of the driving member 4 during the clockwise turning process in which the driving member 4 returns to the initial position after the lens driving member 5 has turned left. When the opening / closing lever 8 falls to the concave cam 4d from the cam edge 4c, the opening / closing lever 8 rotates clockwise by a spring 10 to open a shutter blade (not shown). When the user moves on the cam edge 4e from above, the opening / closing lever 8 turns counterclockwise against the spring 10 to close the shutter blade (not shown).

Then, immediately before the driving member 4 further turns clockwise and returns to the initial position, when the protrusion 4 f formed on the driving member 4 repels the cam 6 b of the ratchet lever 6, the ratchet lever 6 is moved by the spring 11. since anti to be free up ratchet gear 5c of the lens drive member 5 with the left-handed, the lens driving member 5 is right-handed by the spring 12 returns to its initial position, one photographing operation is completed.

[0007]

As will be apparent from the above description, in the case of the above-mentioned conventional mechanism, the ratchet lever 6 is used in addition to the inertial forces of various mechanical members when the stepping motor 1 rotates forward. A spring 11 for operating and a spring 12 for returning the lens driving member 5 to an initial position
And the like are also applied as loads, so that the load on the step motor 1 becomes extremely large. Therefore, it becomes necessary to increase the motor output, and the motor supply voltage increases. And
This increase in the motor supply voltage results in an increase in the battery check voltage of the entire camera, and a decrease in the number of images that can be taken. Further, there is a problem that the motor itself is increased in size to improve the motor output, and the entire shutter mechanism is increased in size.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and a spring 1 for returning the lens driving member 5 in the above-mentioned conventional mechanism to an initial position.
To provide a novel mechanism capable of eliminating the spring 11 for operating the ratchet lever 2 and the ratchet lever 6, thereby providing a shutter drive mechanism that also serves as a lens drive mechanism capable of reducing the motor load. Aim.

In summary, the lens shutter driving mechanism which also functions as the lens driving mechanism of the present invention is similar to the above-described conventional mechanism: a stepping motor (20) capable of normal and reverse rotation.
And: Connected to the step motor and run in both forward and reverse directions.
And a driving member (24) for driving the photographing lens (26).
The lens drive cam is formed, and the rotation of the step motor is performed.
The rotation is transmitted through the driving member to allow the
Travel on a plane substantially perpendicular to the optical axis of the shadow lens
With lens drive member (25): the lens drive member is intended
The driving member is moved to the initial position until the focusing position is reached.
After traveling in the forward direction from above, the driving member returns to the initial position.
To open and close the sector in the process of traveling in the opposite direction
And opening and closing members (24e, 24f, 24g, 28)
Shutter drive mechanism that doubles as the lens drive mechanism
T: The lens drive cam is connected to the optical axis of the photographing lens.
Process in which the lens driving member travels on a plane orthogonal to the plane
The traveling of the lens driving member is controlled by the optical axis of the photographing lens.
Inclined plane that converts the movement into a direction and transmits it to the taking lens
And the traveling of the lens driving member is controlled by the light of the photographing lens.
A flat surface that does not convert to axial movement alternates
Each flat surface corresponds to a set step position of the photographing lens.
Consisting of corresponding stepped cams (25a, 25b, 25c):
The distance between the driving member and the lens driving member is
When the driving member travels in the forward direction, the driving member
First interengaging portion for pushing the lens driving member in the forward direction
(24b, 25d), and the driving member runs in the opposite direction.
The driving member pushes the lens driving member in the reverse direction.
Forming moving second interengaging portions (24c, 25e)
At the same time, when the driving member travels in the forward direction,
The first interengaging portion maximizes the lens driving member in the forward direction.
In the traveling process of the driving member in the reverse direction after the pushing operation,
Until the second interengaging portion pushes the lens driving member
Wherein at least the sector opening / closing member is capable of opening / closing the sector.
Provide an interval at which driving can be completed:
After the movement, the lens driving member is moved to an initial position of the lens driving member.
The drive member in the opposite direction until it reaches
The above object is achieved by eliminating the need for a spring and a ratchet mechanism for returning the lens drive member to the initial position.

[0010]

In other words, according to the present invention, the lens driving member moves in the opposite direction after passing through the initial position of the driving member after the operation of the sector opening / closing member, thereby causing the lens driving member to engage with the second engaging portion. The engagement returns to the initial position, so that the spring for returning the lens driving member to the initial position can be removed. The spring for returning the initial position of the lens driving member is removed, and the lens driving cam for driving the photographing lens system is constituted by a stepped cam having at least the number of steps corresponding to the set number of photographing lenses. Even if the ratchet mechanism is removed, the lens can be positioned. Therefore,
A spring for returning the lens to its initial position and a ratchet mechanism are not applied to the motor as a load, so that the load can be reduced.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a shutter driving mechanism which also serves as a lens driving mechanism according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view showing a part of the shutter driving mechanism. The output pinion 21 of the step motor 20 meshes with a rack 24a formed on the drive ring 24 via a two-stage gear composed of a large-diameter gear 22 and a small-diameter gear 23, and the rotation of the output pinion 21 is transmitted through the transmission train. And transmitted to the drive ring 24 via
The drive ring 24 turns around the center of the exposure aperture in the same direction as the output pinion 21.

Reference numeral 25 denotes a lens drive ring which is rotatably supported about the center of the aperture for exposure similarly to the drive ring 24.
The number of stepped cams 25a, 25b, 25c equal to the number of set steps of the photographing lens is formed at 120 ° intervals on the side surface of the subject. Reference numeral 26 denotes a lens barrel in which a photographing lens is inserted. Cam followers 26a, 26b, 26c formed at 120 ° intervals on the outer side of the lens barrel 26 correspond to stepped cams 25a, 25b, 25c, respectively. Contact, lens barrel 26
Is biased in the direction of the lens drive ring 25 by a spring 27. As clearly shown in FIG.
The stepped cams 25a, 25b and 25c are lens driving rings.
25 travels in a direction perpendicular to the optical axis of the lens barrel 26.
Lens lens barrel 26 is converted into a movement in the optical axis direction to form a lens barrel.
The transmission of the inclined surface and the running of the lens drive ring 25
The flat surface which is not converted into the movement of the lens barrel 26 in the optical axis direction is
The lens drive ring 2 is alternately repeated.
When 5 rotates counterclockwise, the lens barrel 26 is extended stepwise.

On the back surface of the lens drive ring 25, an engagement pin 25d located on the left-handed path of the engagement end face 24b formed on the outer edge of the drive ring 24 is implanted, and is engaged with the engagement end face 24b. The mating pin 25d forms a first engagement portion,
In the process of the drive ring 24 turning left from the initial position,
When the engagement end face 24b engages the engagement pin 25d, the lens drive ring 25 rotates leftward following the drive ring 24.

Further, on the back surface of the lens drive ring 25,
An engagement pin 25e located on the clockwise path of the engagement end face 24c formed on the outer edge of the drive ring 24 is implanted, and the engagement end face 24c and the engagement pin 25e serve as the second engagement portion. In the process of forming and turning the drive ring 24 clockwise from the initial position, the lens drive ring 25 follows the drive ring 24 and turns clockwise from the time when the engagement end face 24c engages the engagement pin 25e.

Reference numeral 28 denotes an opening / closing lever for opening and closing the shutter blades. The opening / closing lever 28 is pivotally supported by a shaft 29 so as to be swingable, and is provided with a right turning property by a spring 30. Open / close lever 2 in the initial state
The right-handed rotation is restricted at a position where the cam follower 28a formed at the position 8 comes into contact with the cam edge 24d formed at the outer edge of the drive ring 24. As shown in FIG. 3, a shutter blade 33 is pivotally supported on a shaft 32 on the back surface of the base plate 31 so as to be swingable. A pin 28 b implanted on the back surface of the opening / closing lever 28 is formed on the shutter blade 33. When the opening / closing lever 28 is turned clockwise with the engagement with the elongated hole 33a, the shutter blade 33 turns clockwise about the shaft 32 to open the exposure aperture 31a.
Although not shown in the drawing, a shutter blade (not shown) symmetrical to the shutter blade 33 is pivotally supported on the shaft 34 of the main plate 31. The shutter blade (not shown) is also a shutter blade 3
3 and operates in common.

The cam edge 2 formed on the drive ring 24
The operation of the cam edges 25f formed on the lens drive ring 25 and the lenses 4e, 24f, 24g will be apparent from the operation described later.

Next, the operation of this embodiment will be described with reference to the above items and FIGS. First, in the initial state,
The mechanism is in the state shown in FIG. 1, and when a forward rotation pulse is supplied to the step motor 20 to rotate the output pinion 21 counterclockwise from this state, the rotation is changed to the large diameter gear 22-small diameter gear 23-.
The drive ring 24 is transmitted to the drive ring 24 via the transmission line of the rack 24a, and the drive ring 24 is turned left. This drive ring 24
Cam edge 24g formed on drive ring 24 in the left-handed turning process
And the cam edge 24f is a cam follower 28 of the opening / closing lever 28.
After passing through the position a, the opening / closing lever 28 slightly turns clockwise by the spring 30, but does not reach the point where the cam follower 28a contacts the cam edge 25f of the lens drive ring 25 to open the shutter blade 33.

As described above, when the drive ring 24 rotates counterclockwise, the lens drive is started from the time when the engagement end face 24b formed on the drive ring 24 engages the engagement pin 25d implanted in the lens drive ring 25. Ring 25 is drive ring 24
Turn left following Accordingly, the lens barrel 26 is extended toward the subject against the spring 27 by the cam followers 26a, 26b, and 26c being driven by the corresponding stepped cams 25a, 25b, and 25c.

FIG. 4 shows the lens driving ring 25 in this manner.
Shows a state in which the cam follower 28a is turned leftward to the maximum extension position.
No. 4 abuts on the cam edge 24e to maintain the shutter closed state.

After the lens driving ring 25 is rotated counterclockwise to the target focusing position as described above, the stepping motor 2 is rotated.
When the output pinion 21 is turned clockwise by supplying a reverse rotation pulse to 0, the rotation of the output pinion 21 is transmitted to the drive ring 24 via the transmission train described above, and the drive ring 24 also turns clockwise.
In this embodiment, the cam for extending the lens barrel 26 is constituted by a stepped cam corresponding to the set number of photographing lenses, and the flat portions of the stepped cams 25a, 25b, 25c correspond to the corresponding cam followers 26a, 26a. Since the lenses 26b and 26c are supported, no external force for rotating the lens drive ring 25 is generated, and the lens drive ring 25 stops at the target in-focus position.

When the drive ring 24 turns clockwise in this manner, the cam follower 28a of the opening / closing lever 28 drops from the cam edge 24e of the drive ring 24 to the cam edge 24f, and the opening / closing lever 28 turns clockwise by the spring 30. FIG. 5 shows the state at this time. When the opening / closing lever 28 rotates clockwise, the shutter blade 33 rotates clockwise about the shaft 32 to engage the exposure aperture 31a while being engaged with the pin 28b at the tip thereof. Open and the stepper motor stops for a time corresponding to the desired exposure time.

When the desired exposure time has elapsed, the output pinion 21 of the step motor 20 starts to rotate clockwise again, and the opening / closing lever 28 moves the cam follower 28a from the cam edge 24g of the drive ring 24 to the cam edge 24d to rotate the shaft 29. , The shutter blade 33 closes the exposure aperture 31a by rotating counterclockwise about the shaft 32.

FIG. 6 shows a state in which the opening / closing lever 28 has turned to the left in this manner. After the end of the exposure operation, the inversion pulse is continuously supplied to the step motor 20, and the output pinion 21 further turns to the right. The drive ring 24 also turns clockwise beyond the initial position. During the clockwise rotation of the drive ring 24,
When the engagement end face 24c formed on the drive ring 24 engages the engagement pin 25e implanted in the lens drive ring 25, the lens drive ring 25 rotates rightward following the drive ring 24. Therefore, the lens barrel 26 is the cam follower 2
The stepped cams 25a,
While descending 25b and 25c, the spring 27 retreats to the initial position by the urging force of the spring 27. FIG. 7 shows a state in which the lens drive ring 25 has returned to the initial position in this manner. After the lens drive ring 25 has returned to the initial position, a forward rotation pulse is applied to the step motor 20 to rotate the output pinion 21 counterclockwise to drive. One photographing operation is completed by returning the ring 24 to the initial position.

In the above description, as shown in FIG.
Example of using a stepped cam, ie, the lens drive member is square
When shooting in the direction, the lens barrel shoots the closest from infinity
I will explain an example where it is fed out stepwise toward the position
However, it is also possible to use a concave step cam.
You. In other words, the inclination between the inclined surface and the flat surface constituting the stepped cam
Lens drive by reversing the slope direction
The lens barrel shoots the closest when the member moves in the forward direction
So that it is gradually pulled from the position to infinity
It is possible. Further, in the above description, an example is shown in which a stepped cam is formed on the lens drive ring side and a cam follower is formed on the lens barrel side. However, a stepped cam may be formed on the lens barrel side. In the above description, an example in which the opening / closing lever is directly driven by the cam formed on the driving ring has been described. However, as long as the opening / closing lever is operated during the return process of the driving ring, a known mechanism is employed. It goes without saying that you can do it. Furthermore, in the above description, an example is shown in which the driving ring, the lens driving ring, or the aperture is turned around, but the present invention can be applied to a case of performing a linear operation.

[0025]

According to the present invention, as described above, a ratchet mechanism for positioning the lens driving member at the in-focus position and a spring for returning the lens driving member to the initial position are mechanically unnecessary. Therefore, the step motor does not need to rotate while charging the ratchet mechanism and the spring for initial return. Therefore, the load applied to the motor is greatly reduced, and the size of the motor can be reduced. Also, the driving voltage of the motor can be reduced, so that the required battery voltage is also low. By doing so, the number of pictures that can be taken increases.

[Brief description of the drawings]

FIG. 1 is a plan view of an initial state of a shutter drive mechanism that also serves as a lens drive mechanism according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of the embodiment.

FIG. 3 is a plan view of the blade peripheral mechanism according to the present invention.

FIG. 4 is a plan view of the embodiment shown in FIG. 1 in a state where the lens is fully extended.

FIG. 5 is a plan view of the embodiment shown in FIG. 1 in a shutter opening state.

FIG. 6 is a plan view of the embodiment shown in FIG. 1 at the end of closing a shutter.

FIG. 7 is a plan view showing a state where the lens driving ring of the embodiment shown in FIG. 1 is returned to an initial state.

FIG. 8 is a plan view of the conventional mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st lens 2 2nd lens 3 3rd lens 4 4th lens 5 5th lens 20 step motor 24 drive ring 24b engagement end surface 24c engagement end surface 25 lens drive ring 25a step cam 25b step cam 25c step cam 25d engagement pin 25e engagement pin 28 opening / closing lever 32 shutter blade

Claims (1)

(57) [Scope of request for utility model registration] 1. A step motor which can rotate forward and backward, a driving member connected to the step motor and traveling in both forward and reverse directions, and a lens driving cam for driving a photographing lens are formed.
The rotation of the step motor is transmitted through the drive member.
Substantially perpendicular to the optical axis of the taking lens
A lens driving member traveling on a plane to be moved, and the driving member travels in a forward direction from the initial position until the lens driving member reaches a target focusing position, and then the driving member moves in a reverse direction toward the initial position. A shutter driving mechanism which also has a sector opening / closing member for driving the sector opening / closing during the course of traveling, wherein the lens driving cam is perpendicular to the optical axis of the photographing lens.
In the process in which the lens driving member travels on a flat surface,
The traveling of the lens driving member is adjusted in the optical axis direction of the photographing lens.
An inclined surface that is converted into a movement and transmitted to the photographing lens;
The movement of the lens driving member is adjusted in the optical axis direction of the photographing lens.
The flat surface that does not convert to the movement of
Each of the flat surfaces is constituted by a stepped cam corresponding to a set step position of the photographing lens, and a front cam is provided between the driving member and the lens driving member.
When the driving member travels in the forward direction, the driving member
First interengaging portion for pushing the lens driving member in the forward direction
And the driving member travels in the reverse direction while traveling.
Pushes the lens driving member in the opposite direction.
The driving member travels in the forward direction
The first interengaging portion becomes the lens driving member
In the reverse direction of the drive member after pushing the maximum in the forward direction
In the traveling process, the second interengaging portion is connected to the lens driving member.
At least the sector opening / closing member is
An interval capable of completing the opening / closing drive of the sector is provided, and after the operation of the sector opening / closing member, the driving member is caused to travel in the reverse direction until the lens driving member reaches the initial position of the lens driving member. A shutter drive mechanism that also serves as a characteristic lens drive mechanism.