JPH0527301A - Barrier mechanism - Google Patents

Abstract

PURPOSE:To obtain the good closing condition of a barrier mechanism having a barrier blade opening and closing in order to protect a photographing lens by using two blades having the same shape. CONSTITUTION:Projections 2d and 3d provided with inclined surfaces with respect to the end faces 2h and 3h of respective barrier blades 2 and 3 are formed on the same positions each other which are the outside of an aperture 1h on the end faces 2h and 3h of the respective barrier blades 2 and 3 rotatably attached to fulcrum shafts 1b and 1a formed on the periphery of the aperture 1i of a base member 1, and recessed parts 2e and 3e provided with the inclined surfaces corresponding to the inclined surfaces of the projections 3d and 2d are formed in order to accept the projections 3d and 2d of the other barrier blades 3 and 2, so that the surfaces of the blades 2 and 3 are positioned on the same level on the condition in which respective barrier blades 2 and 3 are closed.

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 the tip of a lens barrel to protect a taking lens.

[0002]

2. Description of the Related Art Conventionally, a barrier mechanism is generally a disk-shaped base member having an opening at the center and attached to the tip of a lens barrel, and two barrier members for opening and closing the opening of the base member. It is composed of barrier blades and an actuation ring for driving the barrier blades. In this type of barrier mechanism, normally, each barrier blade is rotatably mounted on a fulcrum shaft formed at two locations around the opening of the base member, and when the opening of the base member is closed, the end surface of each blade is You can match them. The actuation ring is also retained on the base member so that it can rotate about the center of the opening. A spring is provided between the actuation ring and the barrier blade as an interlocking means for interlocking the movement of the actuation ring with the barrier blade, and when the actuation ring is rotated with respect to the base member, the rotation is transmitted through the spring. It is transmitted to the wings. Further, generally, when the opening is closed, the operating ring is rotated to a position where the spring is overcharged, and the biasing force is used to obtain a reliable closed state of the lens barrel by the barrier blade. .

The end faces of the blades that abut against each other are generally formed as inclined faces. However, in this case, since the inclination direction of the inclined surface must be reversed for each blade, the two blades must be formed as parts of different shapes, and inventory management and assembly are complicated. In order to deal with this problem, it is conceivable to form each end face at a right angle to the surface of the blade to form the two blades as parts of the same shape, but in that configuration, the biasing force of the above-mentioned spring has an influence. Then, when the barrier is closed, the surfaces of the blades may be displaced, dust may be caught, or the lens barrel may not be sufficiently closed. It is also possible to reverse the inclination direction of the inclined surface at the central portion of the end surface of each blade so that the two blades are the same component, but in that configuration, a deviation occurs in the mating surface when the blades are closed. Therefore, there is a problem that the appearance is not good.

Therefore, the technical problem to be solved by the present invention is to provide a barrier mechanism in which two lens-barrel blades having the same shape can be used to surely close the lens barrel and which has a good appearance. Is.

[0005]

A barrier mechanism according to the present invention comprises a base member having a substantially disc shape and having an opening at its center,
Two barrier blades of the same outer shape, which have end faces that are attached to the base member so as to be rotatable with respect to fulcrum shafts that are located opposite to each other around the opening, and that rotate about the center of the opening. A barrier mechanism including an actuation ring that is held by the base member as much as possible, and an interlocking device that opens and closes an opening by interlocking a barrier blade with rotation of the actuation ring with respect to the base member. In order to solve it, it is configured as follows.

That is, each of the barrier blades has a protrusion having an inclined surface with respect to the end surface at the same position on the outer side of the opening on the end surface, and the surface of each barrier blade is located on the same plane. Further, it has a concave portion having an inclined surface formed corresponding to the inclined surface of the protrusion to receive the protrusion of the barrier blade on the other side.

[0007]

In the above structure, when the operating ring is rotated, the rotation of the operating ring causes the barrier blades to interlock with each other to open and close the opening of the base member. When the barrier blades are closed, the projections and the recesses formed on each end face mesh with each other, and the surfaces of the barrier blades are located on the same plane due to the action of each slope.

In this structure, although the two barrier blades have the same shape as each other, even if a spring for overcharging is conventionally provided between the barrier blade and the operating ring while the barrier blade is closed, the urging force of the spring is provided. Therefore, since the surface of each barrier blade does not shift, malfunction does not occur due to biting of dust or the like. Further, since the projections and the recesses on the end surface of the barrier blade are provided outside the opening of the base member, the mating surface of the barrier blade does not shift within the opening of the base member.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A barrier mechanism according to one embodiment of the present invention shown in FIGS. 1 to 6 will be described in detail below. In addition,
The taking lens barrel applied to this embodiment is a collapsible zoom lens barrel, and the barrier mechanism is such that the taking lens is in an open state between the tele end and the wide end and moves from the wide end to the retracted position. Sometimes it will close automatically.

FIG. 1 is an exploded perspective view of this barrier mechanism. In the figure, 1 is a circular base member having an opening 1i in the central portion, 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 is an actuation ring rotatably mounted on the base member 1 for driving. Further, 8 is a drive lever for rotating the actuation ring 4 with respect to the base member 1, and 9 is a lens barrel configured to be movable in the optical axis direction of the taking lens.

The barrier blades 2 and 3 are formed in the same shape as the base portions 2f and 3f and the cover portions 2g and 3g. Through holes 2a, 3a and hooks 2b, 3b are formed in the base portions 2f, 3f, and the cover portions 2g, 3g have stopper projections 2c, 3c for closing the opening 1i and the respective cover portions 2g. , 3g are formed with positioning protrusions 2d, 3d and positioning recesses 2e, 3e for preventing them from shifting in the direction perpendicular to the plane. The positioning protrusions 2d and 3d are the end faces 2 of the cover portions 2g and 3g.
A surface inclined with respect to the end faces 2h, 3h is formed on the tip side of the h, 3h, and the positioning recesses 2e, 3e are formed by the end faces 2h, 3h.
It is provided at a position of 3h on the base portion 2f, 3f side so as to form an inclined surface which overlaps with the inclined surfaces of the positioning projections 2d, 3d when the both end surfaces 2h, 3h are superposed. Further, the positioning protrusions 2d and 3d and the recesses 2e and 3e respectively have openings 1i.
It is provided at a position on the outside of.

The base member 1 supports the respective barrier blades 2 and 3 in a rotatable manner so that the base portions 2f and 3f of the barrier blades 2 and 3 are supported.
Fulcrum shafts 1b, 1a inserted into through holes 2a, 3a formed in
Are formed. Two opposing edges of the base member 1
Hook-shaped holding portions 1c, 1d are formed at the locations for holding the operating ring 4 rotatably, and the operating ring 4 is attached to the operating ring 4 by a bayonet method with respect to the holding portions 1c, 1d. Therefore, the L-shaped mounting portions 4c and 4d and the openings 4i and 4j are formed. On the other hand, hooks 4a and 4b are formed on the operating ring 4, and springs 5 and 6 are hooked between the hooks 4a and 4b and the hooks 2b and 3b of the barrier blades 2 and 3, respectively. Therefore, the hooks 2b and 3b are normally in contact with the end faces 4h and 4g by the urging force of the springs 5 and 6. Further, the operating ring 4 has another hook 4e, and the hook 1h is provided on the peripheral portion of the base member 1.
Are formed. A spring 7 is hung between the hooks 4e and 1h so that the hook 4e can be pulled toward the hook 1h.

FIG. 2 shows a view as seen from the side of the operating ring 4 in a state where the above-described base member 1, barrier blades 2, 3, operating ring 4 and springs 5, 6, 7 are assembled. However, the operating ring 4 is shown in phantom to clearly show the state of the blades 2 and 3. As shown in this figure, when the members are simply assembled, the actuation 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. Since it is pushed in, the opening 1i is opened as shown in FIG.

On the other hand, in order to drive the barrier blades 2 and 3 to open and close when retracted, 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.
On the inner surface of the lens barrel 9, a drive lever 8 that engages with the drive arm 4f and rotationally drives the operating ring is provided slidably in the optical axis direction. The drive lever 8 is formed in a shape such that the rear end of an elongated plate-shaped member is bent at a substantially right angle as an engaging portion 8a with the body side, and the engaging portion 8a has a pin 8b at the distal end side. Fixed towards. A slanting cam surface 8c is formed at the tip of the drive lever 8, and a rectangular elongated hole 8d and an overhanging portion 8e protruding outward slightly on the tip side of the elongated hole 8d are formed in the middle 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 so as to slidably receive the drive lever 8 in the optical axis direction and to contact the protruding portion 8e. The groove 9d is provided with a pin 9e which fits in 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 that extends in a brim shape toward the outer peripheral side of the lens barrel 9 so as to maintain the movement of the drive lever 8 in the optical axis direction. ing. In addition, a protrusion 10 is formed on the body of the camera to restrict the backward movement of the drive lever 8 by coming into contact with the engaging portion 8a of the drive lever 8 when the lens barrel 9 moves backward along the optical axis.

On the other hand, as shown in FIG. 1, the barrier blades 2, 3 and the operating ring 4, are provided at four locations on the peripheral edge of the base member 1.
In order to attach the barrier unit constituted by assembling the springs 5, 6 and 7 to the base member 1 to the lens barrel 1, a plate-shaped flexible mounting portion 1g is formed, and each mounting portion 1g is formed at the center thereof. Each has a square hole 1j formed therein.
The tip of the inner surface of the lens barrel 9 is stepped by a shoulder portion 9b, and the step 4 corresponds to each mounting portion 1g of the base member 1.
A step is formed by a shoulder portion 9c which is connected to the shoulder portion 9b so that each mounting portion 1g can be received. In addition, a protrusion 9a that fits into the square hole 1j of each mounting portion 1g is formed at approximately the center of the portion surrounded by the shoulder portion 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,
In this mounted state, the shoulder portion 9b of the lens barrel 9 is substantially in contact with the peripheral edge portion of the operating ring 4 and holds the operating ring 4 between itself and the base member 1. Therefore, even if a force as shown by F in the figure is applied, the actuation ring 4 is
Since it can be prevented from coming off or moving out of the way, stable movement of the barrier mechanism can be secured. In the past, a pressing member for pressing the actuation ring 4 against the base member 1 was generally provided separately, but with this structure, the lens barrel can be downsized.

Next, the operation of this barrier mechanism will be described. First, when the lens barrel is extended to the wide end or to the tele end side thereof, as shown in FIG. 4 (a), the rear end of the drive arm 4f and the protrusion 10 on the body side make the length of the drive lever 8 longer. 2, the operating ring 4 is kept in the position shown in FIG. 2 by the biasing force of the spring 7. 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, as shown in FIG. 4B, the engaging portion 8a of the drive lever 8 comes into contact with the protrusion 10 and its rearward movement is impeded, and the cam surface 8c at the tip end is prevented. Contacts the drive arm 4f. Since the lens barrel 9 itself continues to retract when retracted, the drive arm 4f moves along the cam surface 8c to the position shown in FIG. 4C, and as a result, the operating ring 4
Rotates counterclockwise in FIG. 2 with respect to the base member 1. Therefore, the blades 2 and 3 are pulled by the springs 5 and 6 as the interlocking means with respect to the actuating ring 4 to rotate counterclockwise around the fulcrum shafts 1b and 1a to close the opening 1i. The lens barrel 9 is adapted to retreat from the position shown in FIG. 4 (c) to the position shown in FIG. 4 (d).
Therefore, the operating ring 4 continues to rotate further in the counterclockwise direction. Since the barrier blades 2 and 3 are already closed in the state of FIG. 4 (c) and cannot rotate any further around the fulcrum shafts 1b and 1a, the end faces 4h and 4g have hooks 2 as shown in FIG.
The springs 5 and 6 are overcharged away from b and 3b to ensure that the barrier remains closed.

FIG. 6 shows the movement of the blades 2 and 3 when the opening 1i is closed in this way. Although the drawing shows the cross section of the positioning projection 2d of each barrier blade 2 and the positioning recess 3e of the barrier blade 3, the cross sections of the positioning recess 2e and the positioning projection 3d are substantially the same except that the right and left are interchanged. Become. Each barrier blade 2, 3
The springs 5 and 6 are displaced from the surface in the optical axis direction.
Since it is biased by, a slight inclination is generated in the gap between the base member 1 and the actuation ring 4. Therefore, when the barrier is closed as it is from the state of FIG. 6A, the protrusions 2d and the recesses 3e of the blades 2 and 3 are displaced and contact as shown in FIG. 6B. However, due to the action of the inclined surfaces formed on the projections 2d and the recesses 3e, the displacement decreases as the blades 2 and 3 are closed, and when the end surfaces 2h and 3h are in close contact with each other, as shown in FIG. 6 (c). The shift is removed. Therefore, in the closed state, there is no gap or gap between the barrier blades 2 and 3, so that it is possible to prevent a malfunction due to the trapping of dust or the like.

On the other hand, in FIG. 4, when the lens barrel 9 is moved backward from the retracted position toward the wide end, the barrier blades 2,
Since the force holding the operating ring 4 in the position for closing 3 is removed, the operating ring 4 is rotated by the biasing force of the spring 7 from the position of FIG. 3 to the position of FIG. Therefore, the springs 5 and 6 are first contracted so that the end faces 4h and 4g and the hooks 2b and 3 are
b and the end faces 4h and 4g push the hooks 2b and 3b, the barrier blades 2 and 3 rotate clockwise around the fulcrum shafts 1b and 1a to open the opening 1i.

Thus, in this embodiment, the operating ring 4
The drive arm 4f is not directly engaged with the protrusion 10 on the body side, and a drive lever 8 movable in the optical axis direction between the drive arm 4f and the body side projection 10 is provided on the inner surface of the lens barrel 9, and the drive lever 4f is connected via the drive lever 8f. Since the projection 10 is engaged, even if the drive lever 8 held by the lens barrel is formed thin, the bending does not matter, and the drive arm 4f of the actuation ring 4 and the projection 10 of the body are short. Even if formed thin, it does not easily bend.
Therefore, even if the mechanism is downsized, stable movement of the barrier can be obtained.

[Brief description of drawings]

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

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

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

4 (a) to 4 (d) are operation state diagrams showing the relationship between the drive lever and the operation ring when the lens barrel is retracted.

FIG. 5 is a cross-sectional view showing an attachment portion of the barrier mechanism to the lens barrel.

6 (a) to 6 (c) are cross-sectional views showing an operation state when closing the barrier blade.

[Explanation of symbols]

1 base member 1a, 1b fulcrum shaft 1c, 1d holding part 1i opening 2,3 barrier blade 2d, 3d positioning protrusion 2e, 3e positioning recess 2h, 3h end face 4 actuation ring 4f drive arm 5,6,7 spring 8 drive Lever 8c Cam means 9 Lens barrel 10 Protrusion 11 Guide part

Claims (2)

[Claims] 1. A base member (1) having a substantially disc-like shape and having an opening (1i) at its center, and a fulcrum shaft (1b, 1a) located opposite to two locations around the opening (1i). Two barrier blades (2, 2) having the same outer shape, which are rotatably mounted on the base member (1) and have end faces (2h, 3h) that are butted against each other.
3), an actuation ring (4) rotatably held by the base member (1) about the center of the opening (1i), and the actuation ring (4)
In the barrier mechanism composed of interlocking means (5, 6) for opening and closing the opening (1i) by interlocking the rotation of the barrier blade with respect to the base member, each of the barrier blades (2, 3) is (2h, 3h) at the same position outside the opening (1i), the end surface (3
h, 2h) having projections (2d, 3d) with inclined surfaces, and the surface of each barrier blade (2, 3) is located on the same plane. (3), the barrier mechanism having concave portions (2e, 3e) having inclined surfaces formed corresponding to the inclined surfaces of the protrusions (3d, 2d). 2. A base member (1) having a substantially disc shape and having an opening (1i) in the center, and a fulcrum shaft located around the opening (1i).
(1b, 1a) rotatably mounted on the base member (1) barrier blades (2, 3), and a holding portion (1c) formed on a part of the peripheral edge of the base member (1) , 1d) is rotatably held with respect to the center of the opening (1i), and the rotation thereof drives the barrier blades (2, 3) to open and close. In the barrier mechanism in which the base member (1) is attached to the tip of the taking lens barrel (9) that can be set to the position, the periphery of the actuation ring (4) is attached to the inner surface of the lens barrel (9). A barrier mechanism characterized in that a shoulder portion (9b) for sandwiching the portion with the base member (1) is formed.