JPH01248144A - Barrier device for photographic lens - Google Patents

Abstract

PURPOSE:To reduce the quantity of operating force of a lens barrier member by arranging a spring means so that a pushing part and a pushed part are drawn mutually and elastically. CONSTITUTION:When a power switch is turned on, a photographic lens barrel is extended forward and lens barrier members 1 and 2 and an operation member 4 also move forth accordingly. At this time, a tension spring 5 rotates the operation member 4 clockwise. The clockwise rotation of the operation member 4 moves the pushed part 1d of the lens barrier member 1 counterclockwise around a shaft 1a by the pushing part 4a of the operation member 4 at the same time, thereby moving the lens barrier members 1 and 2 to open positions. In this case, the spring means 3 which energizes the lens barrier members 1 and 2 in closing directions reduces the energizing force for closing the lens barrier members 1 and 2 by putting the fitting part 4c close to the fitting part 1c of the lens barrier member 1. Consequently, the tension spring 5 as a driving source for rotation is not affected by the spring means 3.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a barrier device for a photographic lens that shields the front surface of a photographic lens and protects the lens when the camera is not in use. It is related to the technology to

[Conventional technology]

FIGS. 3(a) and 3(b) show perspective views of a conventional barrier device for a photographic lens. In these figures, reference numeral 1.2 denotes a lens barrier member, which is placed in front of a photographic lens (not shown).
It covers the front of the lens when not in shooting mode to protect the lens from damage.

The lens barrier members 1 and 2 are meshed with each other by sector gears lb and 2b, and are rotatably supported by shafts 1a and 2a so that opening and closing operations of one are simultaneously transmitted to the other. Torsion springs 7.8 are attached to the shafts 1a, 2a, one end is locked to the locking protrusions 1e, 2e erected on the lens barrier members 1, 2, and the other end is fixed to the lens barrel (not shown). It is locked to the locking arms 9a and 9b, and the lens barrier member 1.2 is always biased in the closed direction. On the other hand, the operating member 4 is biased clockwise in the figure by a tension spring 5.

In FIG. 3(a), the locking portion 4b of the operating member 4 rides on the cam surface 6a of the locking member 6 protruding from the camera body (not shown), and is rotated counterclockwise. Therefore, the pushing member 4a of the operating member 4 is
The lens barrier member 1.2 is held in a closed state by the urging force of the torsion springs 7 and 8.

Figure 3(b) shows the open state, but (a)
In the closed state, when the power switch (not shown) is turned on, the lens barrel (not shown) moves in front of the camera body (towards the left in the figure).
, the locking portion 4b and the locking member 6 are separated, and the operating member 4 is rotated clockwise by the tension spring 5. When the operating member 4 rotates a little, the pushing member 4a comes into contact with the pushed member 1d of the lens barrier member 1. Thereafter, the operating member 4 rotates the lens barrier member 1.2 against the biasing force of the torsion springs 7 and 8 to open the lens barrier member 1.2, and after opening, the state (t)) is maintained by the tension spring 5. Therefore, the tension spring 5 must have enough force to overcome the force of the torsion springs 7 and 8 and keep the lens barrier member open, and must be quite strong.

[Problems to be Solved by the Invention] However, according to the above configuration, when the lens barrier member 1.2 is open, the torsion spring 7.8 has the strongest biasing force, and it is difficult to change from the open state to the closed state. In the case of shifting, a large contact pressure is applied when the locking portion 4b and the cam surface 6a come into contact, which may damage the cam surface 6a or apply an excessive load to the drive motor, causing malfunction.

The present invention has been made in view of the above-mentioned facts, and an object of the present invention is to reduce the amount of force required to operate a lens barrier member.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a lens barrier member that is provided to open and close the front surface of a photographic lens and has a pushed part, a spring means that biases the lens barrier member to a closed position, and a pushed and pushed part. and an operating member that opens the lens barrier member by pushing the pushed part with the pushing part, the spring means having one end attached to the lens barrier member, The other ends are respectively locked to the operating members, and the pushing part and the pushed part are arranged so as to elastically draw each other toward each other.

〔Example〕

Embodiments of the present invention will be described below based on the drawings. 1st
In Figures (a) and (b), the former shows a state in which the lens barrier members 1 and 2 are closed, blocking the front surface of the photographic lens (not shown). The members 1, 2 and the operating member 4, which can be rotated to open and close the lens barrier members 1, 2, are in a retracted position toward the locking member 6, which is shown as part of the camera body, and the latter is lens barrier member 1
．． 2 is opened, and the front surface of the photographic lens is opened, indicating a state in which photography is possible. In this case, together with the photographic lens, the lens barrier members 1 and 2 and the operating member 4 are moved from the locking member 6 side in the optical axis direction. The locking portion 4b of the operating member 4 is positioned away from the end of the locking member 6 toward the front and to the left in the drawing.

The lens barrier members 1 and 2 are provided with an annular operating member 4 as means for switching between the closed state shown in FIG. 1(a) and the open state shown in FIG. 1(b). The member 4 moves from the position where movement is prevented by the locking member 6 in FIG. 1(a) (hereinafter referred to as the "first position of the operating member") to the locking member 6 as shown in FIG. 1(b). By separating from the operating member, the operating member is rotated clockwise and switched to the stopped position (hereinafter referred to as the "second position of the operating member").

The operating member 4 includes a locking portion 4b that can engage and disengage with the locking member 6 as described above, and a locking portion 4b formed on the lens barrier member 1 in order to open the lens barrier members 1 and 2 by clockwise rotation of the operating member 4. In the first position of the operating member, the pushing member 4a that engages with the pushed member 1d is held in tension with the mounting portion 1c on the lens barrier member 1 side, and in the second position of the operating member, the pushing member 4a engages with the pushed member 1d. Similarly, there is provided a mounting portion 4c of the spring means 3 made of a coil spring which is locked in a relatively relaxed state between the mounting portion 1c and the mounting portion 1c. At the first position of the operation member 4, that is, the position where the rotation of the operation member 4 is prevented by the locking member 6, the pushing member 4a and the pressed member 1d of the operation member 4
In between, a spring means 3 is provided which ensures the closed state of the lens barrier members 1 and 2 and which accompanies the clockwise rotation of the operating member 4.
An appropriate interval is provided to relieve tension between the two, but if the above conditions are met, the two may be placed in contact without providing this interval.

The locking portion 4b of the operating member 4 is provided with a tension spring 5 for rotating the operating member 4 from the first position to the second position.

Next, the lens barrier members 1 and 2 and the lens barrier member 1,
Spring means 3 for biasing 2 into the closed position will now be described. Lens barrier members 1.2 are rotated around shaft portions 1a and 2a, and sector gears lb and 2b formed at the ends are engaged with each other, and the lens barrier members 1 and 2 are opened and closed by the biasing force applied to lens barrier member 1. perform an action.

As mentioned above, one end of the spring means 3 is locked to the mounting portion 4C of the operating member 4, and the other end is locked to the mounting portion 1c of the lens barrier member 1. The mounting portion 1c is provided at a position on the operating member 4 that relieves the tension of the spring means 3 when the operating member 4 is moved to the first position. It is provided at a position on the lens barrier member 1 that urges the lens barrier member 1 in a counterclockwise direction around It is located in

In the above configuration of the present invention, when the power switch (not shown) is turned on in order to switch to the photographing preparation state in the state shown in FIG. 1(a), the photographic lens barrel is extended forward; Accordingly, lens barrier members 1 and 2
The operating member 4 also moves forward. When the operating member 4 moves forward, the end of the locking portion 4b of the operating member 4 is moved along the inclined surface of the cam surface 6a formed on the locking member 6 by the tension spring 5. from the first position to Figure 1 (b
) clockwise to the second position shown.

This clockwise rotation of the operating member 4 is simultaneously caused by the pushing portion 4a of the operating member 4 and the pushed portion 1 of the lens barrier member l.
d in the counterclockwise direction around the axis 1a, as shown in Fig. 1 (
As shown in b), the lens barrier members 1 and 2 are moved to the open position.

In this case, between the operating member 4 and the lens barrier member 1,
The spring means 3 biasing the lens barrier member 1.2 in the direction of closing causes the attachment portion 4C of the operation member 4 to approach the attachment portion IC of the lens barrier member 1 at the beginning of clockwise rotation of the operation member 4. By doing so, the lens barrier member 1.
After the urging force for closing 2 is removed and the pushing part 4a comes into contact with the pushed part 1d, no action beyond maintaining this contact is performed.

Therefore, when the operating member 4 rotates clockwise from the first position of the operating member 4 where the lens barrier member 1.2 is closed, the tension spring 5 serving as its driving source is completely influenced by the spring means 3. Therefore, the tension spring 5 that drives the operating member 4 only needs to have a minimum biasing force.

To switch the lens barrier members 1 and 2 from the open position to the closed position in FIG. 1(C), the operating member 4 is moved backward in the opposite direction to the above-described operation. Due to this retreat, the locking portion 4 of the operating member 4
By moving b along the cam surface 6a of the locking member 6, the operating member 4 rotates counterclockwise and reaches the first position, and the lens barrier members 1 and 2 are closed. in this case,
In the open position of the lens barrier members 1 and 2, the biasing force of the spring means 3 does not act on the rotation of the operating member 4, and the biasing force of the tension spring 5 is small, so that the locking portion 4b is attached to the cam surface. It moves while lightly sliding in contact with the cam surface 6a, and can operate smoothly without damaging the cam surface 6a or overloading the motor.

With this rotation of the operating member 4 in the counterclockwise direction, the spring means 3
Due to the urging force, the pushed member 1d follows the pushing part 4a, and the lens barrier member 1 is therefore rotated counterclockwise around the shaft 1a, and is brought into the closed state shown in FIG. 1(a). brought about. At the end of this rotation, the lens barrier member 1
, 2 come into contact with each other and the closing is completed, the pushing part 4a
moves away from the pushed portion 1d, and the spring means 3 is slightly tensioned. This can more reliably prevent the lens barrier member from opening when the camera receives a physical shock.

FIG. 2 shows another embodiment of the invention.

The difference from the first embodiment is that a cam surface 6a of a locking member 6 and a tension spring 5 are used as means for switching and driving the operating member 4 from the first position to the second position and from the second position to the first position.
Instead, it consists of a driving member 1° that can move between the first position and the second position of the operating member, and the driving member 10 has a long groove 10 that allows the locking portion 4b of the operating member 4 to move in the front-rear direction.
a is formed. The drive member 10 can be moved with a small force in the direction F1 from the position shown in FIG. 2(a) and in the direction F2 from the position shown in FIG. 2(b).

The present invention can be effectively applied to a configuration in which a lens barrel is moved by a motor, such as a bifocal switching camera or a zoom lens, in which a lens barrier device is operated by moving the lens barrel.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, the lens barrier member can be opened and closed with a light force, and therefore, excessive load can be prevented from being applied to the entire lens barrier device, and malfunction of the drive motor can be prevented. It can be prevented.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1(a) is a perspective view of a lens barrier device according to an embodiment of the present invention when it is closed, and a perspective view when it is opened; FIG. 2(a) is (b) is a perspective view of another embodiment of the present invention when closed and a perspective view when opened; FIGS. 3(a) and 3(b) are perspective views of a conventional example of the lens barrier device when closed; FIG. 3 is a perspective view when opened. 1.2... Lens barrier member, 1d... Pushed member, 3... Spring means, 4... Operating member, 4a... Pushing member. 1゜(b) Figure 1b (bl 582)

Claims (1)

[Claims] A lens barrier member is provided to open and close the front surface of the photographing lens and has a pushed part, a spring means for biasing the lens barrier member to a closed position, and a pushing part, and the pushing part pushes the pushed part. In the lens barrier device, the spring means includes an operating member that opens the lens barrier member by pushing the pushing portion, and the spring means has one end locked to the lens barrier member and the other end locked to the operating member. A barrier device for a photographing lens, characterized in that the pushing part and the pushed part are arranged so as to elastically attract each other.