JP3109147B2 - Barrier 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 barrier mechanism attached to a front end of a lens barrel for protecting a taking lens.

[0002]

2. Description of the Related Art Conventionally, a barrier mechanism is generally a disk-shaped member having an opening at the center and attached to the tip of a lens barrel, and two barrier blades for opening and closing the opening of the base member. , An operating ring for driving the barrier blades, and a driving member for driving the operating ring. In this type of barrier mechanism, normally, the barrier blades are rotatably mounted on fulcrum shafts formed at two places around the opening of the base member, and the operating ring is attached to the base member so that it can rotate around the center of the opening. Will be retained. In this configuration, the operating ring is rotated by the driving member provided on the base member side, the rotation is transmitted to the barrier blade, and the opening and closing of the opening by the barrier blade is performed according to the rotation direction.

On the other hand, in order to automatically open and close the barrier blade at the start and end of use of the camera, for example, the lens barrel is configured to be retracted, and the barrier blade is closed using the movement of the lens barrel when retracted. There is provided a barrier mechanism that opens a barrier blade when the lens barrel is extended from a retracted position to a photographing position. For this purpose, for example, a drive arm extending rearward (film surface side) along the optical axis is formed on the operating ring, and an oblique cam surface with which the drive arm abuts during collapse is fixed to the camera body side. What was formed in the drive member is known. In a camera equipped with a barrier mechanism having this configuration, when the lens barrel is retracted, the drive arm is guided by the cam surface of the drive member, and the operating ring rotates with respect to the base member. If the direction of the cam surface is set so as to satisfy the condition, the barrier can be always kept closed when the camera is not used. Generally, the operating ring is always urged in a direction to open the barrier blade, so that if the lens barrel is extended from the retracted position to the photographing position, the drive arm is released from the cam surface, and the barrier is always kept open.

[0004]

However, in the barrier mechanism having this structure, the operating ring attached to the distal end of the lens barrel is located at a considerable distance from the camera body side, so that the drive mechanism fixed to the body side is required. To engage the cam surface of the member and the drive arm of the operating ring when the lens barrel is retracted,
The drive arm or drive member must be lengthened. Therefore, they tend to bend when engaged, and there is a possibility that the operation accuracy of the barrier may be reduced. Further, in order to prevent a decrease in accuracy, the drive arm and the drive member of the operating ring must be formed thick and large, so that the lens barrel tends to be large.

As described above, in the conventional barrier mechanism, it is difficult to reduce the size of the lens barrel in order to obtain good operation accuracy. Therefore, the technical problem to be solved by the present invention is:
It is to achieve both good operation accuracy and downsizing of the barrier mechanism.

[0006]

SUMMARY OF THE INVENTION A barrier mechanism according to the present invention includes a base member having an opening at a substantially central portion, and the base member being movable between a position where the opening is opened and a position where the opening is closed. A photographing position comprising a mounted barrier blade, an operating member rotatably held by the base member and opening and closing the barrier blade in accordance with the rotation direction, and a driving member driving the operating member; A barrier mechanism in which the base member is attached to the tip of a taking lens barrel that can be set to a non-photographing position and a non-photographing position. The barrier mechanism is configured as follows to solve the above-mentioned technical problem.

That is, the driving member includes a first driving member slidably mounted on the inner surface of the lens barrel in the optical axis direction, and a second driving member fixed in the body of the camera. The first driving member includes an engagement portion that engages with the second driving member when the lens barrel moves from a photographing position to a non-photographing position to restrict movement of the first driving member. And cam means for rotating the operating member with respect to the base member by moving the lens barrel from the photographing position to the non-photographing position between the first driving member and the operating member. In the present invention,
The barrier blade includes an urging member that urges the operating member in a direction in which the opening is opened, and according to the urging force of the urging member when the lens barrel moves from the non-imaging position to the imaging position. When the operating member rotates, the barrier blade opens the opening, and when the lens barrel moves from the shooting position to the non-shooting position, the cam means opposes the urging force of the urging member. The operating member rotates,
Preferably, the barrier blade is configured to close the opening.

[0008]

In the above arrangement, when the lens barrel moves from the photographing position to the non-photographing position, the engaging portion of the first driving member engages with the second driving member, and the movement is restricted. At this time, if the lens barrel is still moved, the positions of the lens barrel and the first driving member relatively change. Since the operating member is mounted on the lens barrel via the base member and does not change its position in the optical axis direction with respect to the lens barrel, the positional relationship between the first drive member and the operating member also changes relatively. Become. Here, since the cam means is provided between the operating member and the first driving member, the cam means changes the relative position between the operating member and the first driving member in the optical axis direction. Is converted into a rotational motion of the operating member with respect to the base member. Therefore, since the rotation direction of the operating member can be appropriately set by the cam means, the barrier can be automatically closed when the lens barrel moves from the photographing position to the non-photographing position. When the lens barrel is changed from the non-photographing position to the photographing position, the first
Since the engagement between the driving member and the second driving member is released, when the urging means for urging the barrier blade in the opening direction is provided, the barrier is always opened when the lens barrel is at the photographing position. Can be kept in a state.

As described above, according to the above-described structure, the engagement operation between the second driving member fixed to the body and the operating member when the lens barrel is moved from the photographing position to the non-photographing position is performed by the lens barrel. Through a first driving member mounted slidably in the optical axis direction on the inner surface of the optical disk. By providing the first drive member, the second drive member and the drive arm of the actuating member can be formed to be short, respectively, so that their bending does not become a problem, and the first drive member is provided on the lens barrel. Since it is held on the inner surface, it does not bend even if it is formed thin. Therefore, if the barrier mechanism having this configuration is used, good operation accuracy can be obtained even if the lens barrel is downsized.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a barrier mechanism according to an embodiment of the present invention shown in FIGS. 1 to 6 will be described in detail. In addition,
The taking lens barrel applied to this embodiment is a retractable zoom lens barrel, and the barrier mechanism is open between the telephoto end and the wide end, and moves from the wide end to the retracted position. Sometimes it closes automatically.

FIG. 1 is an exploded perspective view of the barrier mechanism. In the figure, 1 is a circular base member having an opening 1i in the center, 2 and 3 are two barrier blades for opening and closing the opening 1i of the base member 1, and 4 is a barrier blade 2 for opening and closing the opening 1i. , 3 to be rotatably mounted on the base member 1 for driving the same. Reference numeral 8 denotes a drive lever for rotating the operation ring 4 with respect to the base member 1, and reference numeral 9 denotes a lens barrel configured to be movable in the optical axis direction of the taking lens.

The barrier blades 2, 3 are formed in the same shape from each other from the base portions 2f, 3f and the cover portions 2g, 3g. The bases 2f, 3f are formed with through holes 2a, 3a and hooks 2b, 3b, and the covers 2g, 3g are provided with stopper projections 2c, 3c for closing the opening 1i, and each cover 2g. , 3g are formed with positioning projections 2d, 3d and positioning recesses 2e, 3e for preventing the two from shifting in the direction perpendicular to the plane. The positioning projections 2d, 3d are the end faces 2 of the cover portions 2g, 3g.
h, 3h are formed on the tip side with respect to the end faces 2h, 3h, and the positioning recesses 2e, 3e
At the position on the base 2f, 3f side of 3h, a slope is formed so as to overlap the slope of the positioning projections 2d, 3d when the end faces 2h, 3h are overlapped. The positioning projections 2d and 3d and the recesses 2e and 3e respectively have openings 1i.
Is provided at a position outside the.

The base member 1 has bases 2f, 3f of the barrier blades 2, 3 for rotatably supporting the barrier blades 2, 3.
Shafts 1b, 1a inserted into through holes 2a, 3a formed in
Are formed. Opposite 2 of the peripheral portion of the base member 1
Hook-shaped holding portions 1c and 1d are formed at the locations to rotatably hold the operating ring 4, and the operating ring 4 is attached to the operating ring 4 to the holding portions 1c and 1d in a bayonet manner. For this purpose, L-shaped mounting portions 4c and 4d and openings 4i and 4j are formed. On the other hand, hooks 4a, 4b are formed on the operating ring 4, and springs 5, 6 are hung between the hooks 4a, 4b and the hooks 2b, 3b of the barrier blades 2, 3, respectively. Therefore, the hooks 2b, 3b normally come into contact with the end faces 4h, 4g by the urging forces of the springs 5, 6. The operating ring 4 has another hook 4e, and a hook 1h is provided on a peripheral portion of the base member 1.
Are formed. A spring 7 is hung between the hooks 4e and 1h to pull the hook 4e toward the hook 1h.

FIG. 2 shows a view from the operating ring 4 side in a state where the base member 1, the barrier blades 2, 3, the operating ring 4, and the springs 5, 6, 7 described above are assembled. However, in order to clearly show the state of the blades 2 and 3, the operating ring 4 is shown by a virtual line). As shown in this figure, when the respective members are simply assembled, the operating ring 4 rotates the hooks 2b, 3b of the barrier blades 2, 3 counterclockwise with respect to the fulcrum shafts 1b, 1a at the end faces 4h, 4g. 2, the opening 1i is opened as shown in FIG.

On the other hand, in order to open and close the barrier blades 2 and 3 during collapsing, a short drive arm 4f extending in a direction parallel to the optical axis is formed on the operating ring 4 as shown in FIG.
A drive lever 8 that engages with the drive arm 4f to rotate the operating ring is provided on the inner surface of the lens barrel 9 so as to be slidable in the optical axis direction. The drive lever 8 is formed such that the rear end of an elongated plate-shaped member is bent at substantially a right angle as an engagement portion 8a with the body side, and a pin 8b is attached to the engagement portion 8a at the distal end. It is fixed towards. An oblique cam surface 8c is formed at the tip of the drive lever 8, and a rectangular long hole 8d and a projecting portion 8e projecting outward slightly at the distal end side from the long hole 8d are formed at the intermediate portion. .

FIG. 4 shows a state in which the drive lever 8 is mounted on the inner surface of the lens barrel 9. As shown in the drawing, a groove 9d is formed on the inner surface of the lens barrel 9 to receive the drive lever 8 slidably in the optical axis direction and to come into contact with the overhang portion 8e. The groove 9d is provided with a pin 9e that fits into the elongated hole 8d of the drive lever 8 and limits the sliding range of the drive lever 8. The pin 8b of the engaging portion 8a of the drive lever 8 is fitted into a guide portion 9f indicated by a broken line which protrudes in a flange shape on the outer peripheral side of the lens barrel 9 so as to keep the movement of the drive lever 8 in the optical axis direction. ing. Further, a projection 10 is formed on the body of the camera so as to contact the engaging portion 8a of the drive lever 8 when the lens barrel 9 is retracted along the optical axis, thereby restricting the retraction of the drive lever 8.

On the other hand, as shown in FIG. 1, the barrier blades 2, 3 and the operating ring 4,
In order to attach the barrier unit formed by assembling the springs 5, 6, 7 to the base member 1 to the lens barrel 1, a plate-shaped and flexible attachment portion 1g is formed. Are each formed with a square hole 1j.
The tip of the inner surface of the lens barrel 9 is stepped by a shoulder 9b, and is located at a position 4 corresponding to each mounting portion 1g of the base member 1.
The location is stepped by a shoulder 9c connected to the shoulder 9b so as to receive each mounting portion 1g. A projection 9a that fits into the square hole 1j of each mounting portion 1g is formed substantially at the center of the portion surrounded by the shoulder 9c.

FIG. 5 is a sectional view showing a state in which a barrier unit is attached to the tip of the lens barrel 9. As shown
The shoulder 9 b of the lens barrel 9 substantially contacts the peripheral portion of the operating ring 4 in this mounted state, and sandwiches the operating ring 4 between the operating member 4 and the base member 1. Therefore, for example, even when a force as shown by F in the drawing is applied, the operating ring 4 is connected to the base member 1.
As a result, it is possible to prevent the barrier mechanism from being displaced or displaced, so that a stable movement of the barrier mechanism is ensured. Conventionally, a pressing member for pressing the operating ring 4 against the base member 1 is generally provided separately. However, with such a configuration, the size of the lens barrel can be reduced.

Next, the operation of the barrier mechanism will be described. First, when the lens barrel is extended to the wide end or the tele end side, the rear end of the drive arm 4f and the projection 10 on the body side are connected to the length of the drive lever 8 as shown in FIG. The operating ring 4 is kept at the position shown in FIG. Therefore, the opening 1i of the base member 1 is always kept open. On the other hand, when the lens barrel 9 starts the collapsing operation, the engaging portion 8a of the drive lever 8 comes into contact with the projection 10 as shown in FIG. Abuts on the drive arm 4f. When the lens barrel 9 is retracted, the lens barrel 9 itself continues to retract, so that the drive arm 4f moves along the cam surface 8c to the position shown in FIG.
Rotates counterclockwise with respect to the base member 1 in FIG. Therefore, the blades 2, 3 are pulled by the springs 5, 6 as interlocking means for the operating ring 4, rotate around the fulcrum shafts 1b, 1a in a counterclockwise direction, and the opening 1i is closed. The lens barrel 9 is retracted from the position shown in FIG. 4C to the position shown in FIG.
Therefore, the operating ring 4 continues to rotate further counterclockwise. Since the barrier blades 2 and 3 are already closed in the state shown in FIG. 4C and cannot rotate any more around the fulcrum shafts 1b and 1a, the end faces 4h and 4g are connected to the hooks 2 as shown in FIG.
Apart from b and 3b, the springs 5, 6 are overcharged, ensuring that the barrier is kept closed.

FIG. 6 shows the movement of the blades 2, 3 when the opening 1i is closed in this way. The figure shows the cross section of the positioning projection 2d of each barrier blade 2 and the positioning concave portion 3e of the barrier blade 3, but the cross section of the positioning concave portion 2e and the positioning projection 3d is almost the same except that the left and right are interchanged. Become. Each barrier blade 2, 3
The springs 5 and 6 are shifted from the surface in the optical axis direction.
, A slight inclination occurs in the gap between the base member 1 and the operating ring 4. Therefore, when the barrier is closed as it is from the state shown in FIG. 6A, the projections 2d and the recesses 3e of the blades 2 and 3 come into contact with each other as shown in FIG. 6B. However, due to the action of the slopes formed in the projections 2d and the recesses 3e, the displacement decreases as the blades 2, 3 are closed, and when the end faces 2h, 3h are in close contact with each other, as shown in FIG. The displacement is eliminated. Therefore, there is no gap or gap between the barrier blades 2 and 3 in the closed state, and it is possible to prevent malfunction due to biting of dust or the like.

On the other hand, in FIG. 4, when the lens barrel 9 is extended from the retracted position to the wide end side, the barrier blades 2 and
Since the force holding the operating ring 4 at the position where the shutter 3 closes is removed, the operating ring 4 rotates from the position shown in FIG. 3 to the position shown in FIG. Therefore, first, the springs 5 and 6 shrink, and the end faces 4h and 4g and the hooks 2b and 3
b, and the end faces 4h, 4g push the hooks 2b, 3b, so that the barrier blades 2, 3 rotate clockwise around the fulcrum shafts 1b, 1a to open the opening 1i.

As described above, in this embodiment, the operating ring 4
The drive arm 4f is not directly engaged with the projection 10 on the body side, and a drive lever 8 movable in the optical axis direction between the drive arm 4f and the drive arm 4f is provided on the inner surface of the lens barrel 9. Since the projection 10 is engaged with the projection 10, even if the driving lever 8 held on the lens barrel is formed thin, the deflection does not become a problem, and the driving arm 4f of the operating ring 4 and the projection 10 of the body are short. It is hard to bend even if formed thin.
Therefore, a stable movement of the barrier can be obtained even if the mechanism is downsized.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a barrier mechanism according to one embodiment of the present invention.

FIG. 2 is a view of the barrier mechanism viewed from a film surface side with an opening being opened.

FIG. 3 is a view of the barrier mechanism viewed from a film surface side with an opening closed.

FIGS. 4A to 4D are operation state diagrams showing the relationship between the drive lever and the operating ring when the lens barrel is retracted.

FIG. 5 is a cross-sectional view showing a portion where the barrier mechanism is attached to the lens barrel.

FIGS. 6A to 6C are cross-sectional views showing an operation state when the barrier blade is closed.

[Description of Signs] 1 Base member 1a, 1b Support shaft 1c, 1d Retaining portion 1i Opening 2, 3 Barrier blade 2d, 3d Positioning protrusion 2e, 3e Positioning concave portion 2h, 3h End face 4 Operating ring 4f Drive arm 5, 6 , 7 spring 8 drive lever 8c cam means 9 lens barrel 10 protrusion 11 guide part

Continuation of front page (56) References JP-A-5-11310 (JP, A) JP-A-2-310551 (JP, A) JP-A-1-248144 (JP, A) JP-A-2-5729 (JP) , U) Hikaru 3-71332 (JP, U) (58) Fields studied (Int.Cl. ⁷ , DB name) G03B 11/04

Claims (2)

(57) [Claims] 1. A base member having an opening (1i) at a substantially central portion.
(1), barrier blades (2, 3) mounted on the base member (1) so as to be movable between a position where the opening (1i) is opened and a position where the opening (1i) is closed, and Held on the base member (1)
Along the optical axis toward the camera body.
An operating member (4) having a portion (4f) having a length and opening and closing the barrier blades (2, 3) in accordance with the rotation direction thereof, and a driving member (8, 10), a barrier mechanism in which the base member (1) is attached to the tip of a photographing lens barrel (9) that can be set to a photographing position and a non-photographing position, wherein the driving member (8, 10) a first driving member (8) slidably mounted on the inner surface of the lens barrel (9) in the optical axis direction, and a light source fixed to the camera body and directed toward the base member (1).
A second driving member (10) extending at a predetermined length in the axial direction, wherein the first driving member (8) is moved by moving the lens barrel (9) from a photographing position to a non-photographing position. engaging portion for restricting the movement of said second drive member (10) and engaged with said first drive member (8) itself and has a (8a), the site (4f of the first driving member and the actuating member Contact area
The barrier of the lens barrel (9) is characterized by forming the cam surface to rotate the actuating member (4) relative to the base member (1) (8c) by moving the non-shooting position from the photographing position mechanism. 2. An urging member for urging the operating member in a direction in which the barrier blade opens the opening,
When the lens barrel moves from the non-photographing position to the photographing position, the operating member rotates according to the urging force of the urging member, and the barrier blade opens the opening, while the lens barrel moves from the photographing position. When moving to a non-shooting position
The barrier mechanism according to claim 1, wherein the cam member rotates the operating member against the urging force of the urging member, and the barrier blade closes the opening.