JP2518485Y2 - Camera lens barrier device - Google Patents

Description

[Technical Field] The present invention relates to a barrier device for a lens used in a zoom lens camera or the like.

"Prior Art and Problems Thereof" Some zoom lens cameras and the like are provided with a barrier device that can open and close the lens opening by operation on the camera body side in order to protect the lens system built in the lens barrel.

In general, such a barrier device, in particular, a barrier device arranged on the front end side of a lens barrel, has a pair of (two) barrier blades arranged in symmetrical positions with the optical axis sandwiched in the lens barrel, and a pair of these barrier blades. It is composed of a link mechanism for rotating the blades. One end of each barrier blade is rotatably supported by the lens barrel,
The links rotate in opposite directions.
Then, the lens openings are closed when the opposite edges of the barrier blades come into contact with each other at a position including the optical axis, and the openings are opened by rotating the lens edges in the direction of separating.

However, in recent years, the lens aperture diameter is increasing due to the enlargement of the lens diameter due to the increase in the focal length, and the barrier blades are unavoidably increased accordingly. On the other hand, the need to make the camera compact makes it impossible to make the lens barrel thick. In this case, if the number of barrier blades is two, the size is too large compared to the diameter of the lens barrel, and the space required for rotation and storage of the barrier blade and its drive mechanism should be secured in the lens barrel. Is getting harder.

Therefore, in high-power zoom lens cameras,
A measure was taken to substitute a lens cap without a barrier device.

However, it is troublesome to remove and attach the lens cap one by one, and there are problems such as missing a photo opportunity due to the operation and easy loss of the cap. For this reason, it has been strongly desired to equip a high magnification zoom lens camera using a large aperture lens with a barrier device.

Therefore, in order to meet this demand, a pair of barrier blades are each divided into two to provide a total of four barrier blades, and when opened, two barrier blades on the same side are stacked and housed to create a narrow space within the lens barrel. Something that could be dealt with was proposed.

In this way, if the number of barrier blades is four, it becomes impossible to drive with one link mechanism, and it has become necessary to use a plurality of link mechanisms.

In a drive mechanism composed of a plurality of links, a limited chain is formed in order to make the movement of the barrier blade constant, and if one of the links forming the limited chain is used as a driving node, the other link and the barrier blade are linked. Becomes a follower and the barrier can be opened and closed. However, in this case, the backlash of the link may cause a situation where the predetermined movement trajectory is not taken.

Such inconvenience can be avoided by using a plurality of driving joints, but in this case, unless the driving joints are operated at the same time and with high accuracy, the barrier blade will not close.

[Purpose of Invention] The present invention has been made in view of the current state of the barrier in the zoom lens camera described above, and it can be housed in a compact lens barrel, and a plurality of barrier blades can be smoothly operated by a plurality of link mechanisms. Can be driven to
It is an object of the present invention to provide a camera lens barrier that operates reliably even in a high-power zoom lens camera using a large-diameter lens.

[Outline of the Invention] In order to achieve this object, the present invention is fitted with barrier blades for opening and closing a lens opening at the front end of a lens barrel of a camera lens, which is a closed position for closing the lens opening and an open position for opening the lens opening. With multiple barrier blades that can slide to and
Each of the barrier blades is provided with two or more links that support each barrier blade and linearly slide between the closed position and the open position, and a drive ring that moves about the optical axis. The link is characterized in that it is connected to the drive ring so as to be rotated by the movement of the drive ring so as to linearly slide the respective barrier blades.

According to this structure, since the barrier blades are driven by two or more links, the barrier blades can be reliably linearly moved in parallel.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings. First
1 to 3 are views showing an embodiment of the present invention.

As shown in FIG. 1, the barrier device for a camera lens of this embodiment includes a lens barrel 1, a barrier block 2 from the front end side (subject side), and a drive ring 3 from the rear end side (camera body side).
Are stored and assembled.

The barrier block 2 has a barrier support ring 4 and a lens barrel cover 7 fixed to the barrier support ring 4 as main fixing portions. Between the barrier support ring 4 and the lens barrel cover 7, four power transmission levers 5, ..., A barrier pressing plate 6 that rotatably holds the power transmission lever 5 with respect to the barrier support ring 4, Main barrier blades 8a, 8b, sub barrier blades 9a, 9b and main barrier blade 8a,
Drive arms 10a, 10b, 11a, 1 for direct actuation of 8b
With 1b.

The barrier support ring 4 has four recessed portions 12, ... For rotatably storing and holding the power transmission lever 5,
It is formed so as to be located on a concentric circle around the optical axis L.

The power transmission lever 5 has a shaft portion 13 rotatably fitted in the recess 12.
And an arm portion 14 protruding from the outer peripheral surface of the shaft portion 13 with the diametrical direction sandwiched therebetween.
And a locking projection 14a. The arm portion 14 extends toward the drive ring 3, and the locking protrusion 14a extends in the opposite direction. The arm portion 14 projects from the barrier support ring 4 to the drive ring 3 side in a state where the shaft portion 13 is housed in the recess 12 of the barrier support ring 4.
The cam surface 16 of the cam portion 15 provided on the peripheral portion of the drive ring 3 is slidably contacted.

A torsion spring 31 is attached to each power transmission lever 5 in order to urge the arm portion 14 into sliding contact with the cam surface 16.
In each torsion spring 31, a coil portion is fitted on a shaft (not shown) formed on the barrier support ring 4, and both whiskers are hooked on the barrier support ring 4 and the arm portion 14, respectively.

The barrier pressing plate 6 is formed with four holes 17 corresponding to the shaft portion 13 of the power transmission lever 5.

One end of each drive arm 10a, 10b, 11a, 11b has a pin
Fix 18 Each of these pins 18 has a hole 17
Is inserted and fitted into a pin hole 19 formed in the corresponding power transmission lever 5, and is rotatably supported relatively. Therefore, each drive arm 10a, 10b, 11a, 11b rotates about the pin 18.

Further, a torsion spring 32 is fitted on each pin 18. One of the whiskers of the torsion spring 32 is locked to the locking projection 14 of the power transmission lever 5, and the other of the whiskers is locked to a locking projection 33 formed on the drive arms 10a and 10b. That is, the power transmission lever 5 and the drive arms 10a and 10b are connected via the torsion spring 32 and rotate integrally.

Each drive arm 10a, 10b is housed along the space between the lens opening 29 and the lens barrel 1 with the main barrier blades 8a, 8b moved to the closed position, as shown in FIG. "What"
It is formed in a bent shape. And each drive arm 10
Each of a and 10b has one end fixed to the tip of the pin 18 and the other end intersecting with the other drive arms 10a and 10b. The pin 20 fixed at the intersection of the one drive arm 10a is fitted into the elongated hole 21 formed at the intersection of the other drive arm 10b. The lower drive arms 11a and 11b in FIG.
Are formed symmetrically with the optical axes of the upper drive arms 10a and 10b.

Further, one drive arm 10a, 11a is provided with holes 22, 22 near the end opposite to the end where the pin 18 is fixed, in order to connect the main barrier blades 8a, 8b, respectively. Similarly, the other drive arms 10b and 11b are provided with elongated holes 23 and 23 near the end opposite to the end to which the pin 18 is fixed.

The main barrier blades 8a and 8b are elongated trapezoidal plates. In the figure, a pair of pins 24 is provided on the upper main barrier blade 8a.
a and 24a are provided, and one pin 24a is loosely fitted in the hole 22 of the drive arm 10a and the other pin 24a is loosely fitted in the long hole 23 of the drive arm 10b. Of course, the lower main barrier blade 8b is similarly provided with a pair of pins 24b, 24b, one of which is loosely fitted in the hole 22 of the drive arm 11a and the other of which is loosely fitted in the elongated hole 23 of the drive arm 11b. In the figure, 25 is a retaining ring for the pins 24a and 24b.

Further, as shown in FIG. 3B, the height dimension hm of the main barrier blades 8a, 8b is set to be smaller than the dimension hc obtained by subtracting 1/2 of the height of the opening 29 from the inner diameter radius of the lens barrel cover 7. There is.

Further, sub barrier blades 9a and 9b are disposed closer to the subject side than the main barrier blades 8a and 8b so as to be slidable to each other.
The sub-barrier blades 9a and 9b are plates formed in a narrow U-shape. On the sub barrier blades 9a and 9b, guide pins 26 are provided so as to project at the center and both ends of the surface on the camera body side, and on the opposite surface (the surface on the main barrier blades 8a and 8b side),
Protruding edges 26a and 26b are formed along the outer edge, and projections 2 are
8 and 28 are projected. The shapes of the inner edges of the projecting edges 26a, 26b correspond to the shapes of the upper edge portions of the main barrier blades 8a, 8b. The projecting edges 26a, 26b form an open contact portion, and the protrusion 28 forms a closed contact portion.

As shown in FIG. 3B, the height hs of the central portion of the sub barrier blades 9a and 9b is set smaller than the dimension hc of the peripheral portion of the lens barrel cover 7.

The lens barrel cover 7 has a lens opening 29 at the center. A guide groove that serves as an operation guide for the sub barrier blades 9a and 9b is provided on the surface of the peripheral edge of the lens opening 29 on the side of the sub barrier blades 9a and 9b.
30 ... are formed. The guide pins 26, ... Of the sub barrier blades 9a, 9b are fitted in the corresponding guide grooves 30, ..., and slide along the guide grooves 30.

The lens barrel cover 7 is configured such that the main barrier blades 8a and 8b, the sub-barrier blades 9a and 9b, and the drive arms 10a, 10b, 11a, and 11b are housed in a space between the lens barrel cover 7 and the barrier pressing plate 6. It is fixed to the barrier support ring 4 from above.

Next, details of the combination state of the main barrier blade 8a and the drive arms 10a and 10b will be described with reference to FIG. FIG. 1 shows a combination state of the upper main barrier blade 8a and the drive arms 10a and 10b. The main barrier blade 8a is a lens aperture.
It is in the closed position with the upper half of the 29 closed.

The combination of the main barrier blade 8a and the drive arms 10a, 10b constitutes a limited chain mechanism, one or both of the drive arms 10a, 10b is the driving node, and the main barrier blade 8a is the driven node.
The main barrier blade 8a can be driven by rotating one or both of the drive arms 10a and 10b, which are the driving nodes.

Specifically, when one of the drive arms 10a and 10b is rotated, the pin 20 and the elongated hole 21 are fitted to each other so that the other drive arm 10 is driven.
b and 10a rotate at the same speed as the one drive arm 10a and 10b and in the opposite direction.

The main barrier blade 8a slides in a direction perpendicular to the line connecting the pins 18 and 18 with the rotation of the drive arms 10a and 10b without changing the inclination of the line connecting the holes 22 and 23. . The holes 22 and 23 are provided with pins provided on the main barrier blade 8a, respectively.
Since 24a is fitted, the main barrier blade 8a also moves in a direction perpendicular to the line connecting the pins 18 with the rotation of the drive arms 10a and 10b.

It should be noted that the holes 22 and 23 move along the arcuate loci along with the rotation of the drive arms 10a and 10b, so that the distance between the holes 22 and 23 changes. Therefore, the hole 23 is used as the long hole and the pin 24a is used as the long hole 2.
It slides along 3 to absorb the change in the above distance.

Further, in the relationship between the main barrier blade 8a and the sub barrier blade 9a, the main barrier blade 8a serves as a driving node and the sub barrier blade 9a serves as a driven node.

 Next, the overall operation of this embodiment will be described.

When the drive ring 3 is rotated by the power of the camera body (not shown) or the operation force of the photographer, the arm portion 14 slidingly contacting the cam surface 16 of the cam portion 15 is pushed along the contour of the cam surface 16 to generate power. The transmission lever 5 rotates about the shaft portion 13 against the rotation biasing force of the torsion spring 31. Then, the drive arms 10a and 10b, which are connected to the power transmission lever 5 via the torsion spring 32, rotate in opposite directions, respectively, and the barrier blades 8 and 9 move in the open position direction or the closed position direction to open the lens opening. Open and close 29.

The above is the outline of the operation of the barrier device. First, the case where the lens opening 29 is opened will be described below. Although only the upper main barrier blade 8a will be described, the operation of the lower main barrier blade 8b is also the same.

When the drive arms 10a and 10b rotate in the arrow "open" direction in FIG. 2, the tip ends to which the main barrier blades 8a are connected respectively rotate upward in the drawing. Then, the main barrier blade 8a connected by the drive arms 10a and 10b and the pin 24a is lifted upward by the rotation of the drive arms 10a and 10b. That is, the main barrier blade 8a slides in the open position direction.

When the main barrier blade 8a is lifted up to a certain extent, the upper edge portion which is the open contact portion of the main barrier blade 8a is moved to the sub barrier blade 9a.
It hits the edge 27 of. Then, the main barrier blade 8a lifts the sub barrier blade 9a, and the sub barrier blade 9a moves vertically upward along the guide groove 30 due to the engagement between the guide pin 26 and the guide groove 30 of the lens barrel cover 7.

Then, with the lower edges of the main barrier blade 8a and the sub barrier blade 9a reaching the outside of the lens opening 29, the movement of the main barrier blade 8a stops, and the main barrier blade 8a and the sub barrier blade 9a overlap each other. It is stored on the back surface of the upper peripheral edge of the lens barrel cover 7 (first
(State of FIG. 3B), the lens opening 29 is completely opened.

The drive ring 3 is controlled so as to stop after the barrier blades 8a and 9a completely open the lens opening 29. Further, the contour of the cam surface 16 is such that the barrier blades 8a and 9a have lens openings.
It is formed so that 29 can be moved to a position where it can be completely opened, and that it cannot move further.

Next, the case where the lens opening 29 is closed from the state shown in FIG. 3B will be described. When the drive arms 10a, 10b rotate in the arrow "closed" direction in FIG. 1, that is, in the downward direction in the figure, the main barrier blade 8a is pushed downward with the rotation of the drive arms 10a, 10b. That is, the main barrier blade 8a moves toward the closed position. During the movement, the lower edge of the main barrier blade 8a, which serves as the closing contact portion, serves as the closing contact portion of the sub barrier blade 9a.
And the auxiliary barrier blade 9a is moved toward the closed position (downward in the figure). In this state, the main barrier blade 8a and the sub-barrier blade 9a have at least the lens opening 29
The edge facing is completely overlapped.

Then, the opposing edge portions 41, 41 of the main barrier blades 8a, 8b come into contact with each other, completely closing the lens opening 29 and stopping (see FIG. 3A).

In this closed state, the barrier blades 8 and 9 are held in the closed position by the biasing force of the torsion spring 32. That is, when a force for moving the main barrier blade 8a in the opening direction is applied, the main barrier blade 8a rises while rotating the drive arms 10a and 10b against the biasing force of the torsion spring 32. Moreover, since both ends of the barrier blade are supported, they do not tilt.

Also, when closing the barrier from the open state, the main barrier blade
When the movement of 8a in the closing direction is blocked, the rotation of the drive arms 10a and 10b is blocked, but the power transmission lever 5 continues to rotate against the biasing force of the torsion spring 32.

As described above, in this embodiment, the lens opening 29 is slid.
Since the drive arms 10 and 11 that move the barrier blades 8 and 9 that open and close to the closed position and the open position are driven via the power transmission lever 5 that is concentrically arranged about the optical axis L,
The power is evenly transmitted to the drive arms 10 and 11, and the barrier blades 8 and 9 operate reliably. Also, each power transmission lever 5
Is driven via a cam mechanism by the drive ring 3 that rotates about the optical axis L, so that the power transmission levers 5 rotate at the same speed at the same time. Therefore, the driving force is simultaneously and evenly transmitted from each drive arm 10 and 11 and each drive arm 10 and 11 to the barrier blade 8.

As described above, in the present embodiment, the drive arms 10 and 11 are driven by the drive ring 3 which rotates about the optical axis.
Can be configured to move linearly or screw along the optical axis. In this case, the cam surface 16 is formed along the movement direction of the drive ring 3.

When the drive ring 3 and the drive arms 10 and 11 are close to each other, the power transmission lever 5 is not provided and the drive arm 1
A cam follower member may be provided at 0 and 11 and slidably contact the cam surface 16 of the drive ring 3.

[Advantages of the Invention] As described above, the device of the present invention supports the slidingly moving barrier blades by a plurality of links and drives each link by the drive ring. The plurality of links can be simultaneously and accurately operated, and the plurality of barrier blades can be smoothly driven by the plurality of links.

The barrier device can be installed in a compact lens barrel of a high-power zoom lens camera using a large-diameter lens.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a barrier device for a camera lens according to the present invention, FIG. 2 is a conceptual diagram showing a drive device for main barrier blades, and FIGS. 3A and 3B are also main barriers and sub barriers. FIG. 3A is a diagram conceptually showing the related operation with, FIG. 3A shows a state in which the lens aperture is closed, and FIG. 3B shows a state in which the lens aperture is open. 1 ... barrel, 2 ... barrier block, 3 ... drive ring, 5
...... Power transmission lever (interlocking member), 7 ... Lens cover,
8a, 8b …… Main barrier, 9a, 9b …… Secondary barrier, 10a, 10b,
11a, 11b …… Drive arm, 13 …… Power transmission lever shaft, 14 …… Power transmission lever arm (lever body), 20 ……
Pins, 21 ... Oval hole, 22 ... Hole, 23 ... Oval hole, 29 ... Lens aperture, 32 ... Torsion spring, L ... Optical axis

Claims (3)

(57) [Scope of utility model registration request] 1. A barrier blade for opening and closing a lens opening at a front end of a lens barrel of a camera lens, the barrier blade being slidable between a closed position for closing the lens opening and an open position for opening the lens opening. Blades, two or more links provided on the barrier blades that linearly slide and move the barrier blades to the closed position and the open position, and a drive ring that moves about the optical axis. A barrier device for a camera lens, wherein each link is connected to the drive ring so as to be rotated by the motion of the drive ring to linearly slide each barrier blade. 2. The barrier blade according to claim 1, wherein the barrier blade is linearly slidably guided by the main barrier blade supported by the link, and is interlocked with the movement of the main barrier blade to close the open position and the closed position. The link includes a pair of drive arms disposed for each of the main barrier blades, and the pair of drive arms have one end portions each having the one end portion in the state of intersecting each other. The lens barrel is rotatably supported by the lens barrel outside the lens opening, and the intersecting portions are connected so as to rotate in conjunction with each other. Further, the other end portions of the pair of drive arms are respectively connected to the main barriers. A barrier device for a camera lens, wherein each main barrier blade is connected to the blade so as to move in parallel between the closed position and the open position. 3. The drive arm according to claim 2, wherein the drive arm is bent along the space so as to be housed in the space outside the lens opening and the lens barrel while the main barrier blade is moved to the open position. A barrier device for a camera lens, which is characterized in that