JP2001083574A - Focal plane shutter for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance quality and to reduce the cost. SOLUTION: This shutter 1 is provided with a shutter base plate 2 having an aperture for photographing 2a, a blade group 3A opening and closing the aperture 2a, a driving member 8 which is freely turnably fitted to the plate 2 and whose one end side is engaged with the group 3A, a spring member 10 energizing the driving member 8 and an electromagnetic actuator 12 having a movable part 11 arranged at a side where the other end (hook piece 13) of the driving member 8 runs by the energizing force of the spring member 10 on the plate 2, engaged with the other end side (hook piece 13 side) of the driving member 8 and linearly moved back and forth at the side where the other end runs. By this constitution, the other end of the driving member 8 can be locked by the tip of the movable part 11 when the movable part 11 is maintained so as to be made to project (advance) from the actuator 12. Besides, when the movable part 11 is retreated in order to release the lock of the driving member 8, the other end of the driving member 8 is turned so as to follow up the retreat of the movable part 11 by the energizing force of the spring member 10. Consequently, since the lock of the driving member 8 and the release thereof can be properly executed by the actuator 12, an electromagnet need not be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focal plane shutter for a camera having a blade group for closing and opening a photographing opening of a shutter base plate.

[0002]

2. Description of the Related Art In general, a focal plane shutter for a camera has a shutter base plate having a photographing opening.
The shutter base plate is provided with a blade group for closing and opening the photographing opening, and a rotatable drive lever is connected to the blade group. In such a focal plane shutter, for example, an electromagnet is provided on the shutter base plate, and the electromagnet holds the drive lever at a position corresponding to the closed position of the blade group or a position corresponding to the open position of the blade group. Like that.

[0003]

However, in the above-mentioned prior art, if dust, oil, water droplets, etc. adhere to the attracting surface of the electromagnet, the drive lever becomes poorly attracted to the electromagnet. In the closed position or the open position, and there is a risk of unexposed, underexposed, or overexposed. In order to prevent such a problem, it is conceivable to provide a dustproof member or the like, but in this case, the cost is increased.

An object of the present invention is to provide a focal plane shutter for a camera which can improve the quality and reduce the cost.

[0005]

According to a first aspect of the present invention, there is provided a focal plane shutter for a camera, comprising: a shutter base plate having a photographing opening; a blade group for opening and closing the photographing opening;
A drive member rotatably attached to the shutter base plate, one end of which engages with the blade group, a spring member for urging the drive member, and the other end of the drive member on the shutter base plate by the urging force of the spring member. An electromagnetic actuator having a movable portion that is disposed on the running side, engages with the other end of the driving member, and linearly reciprocates on the running side with the other end.

An electromagnetic actuator used for this camera focal plane shutter is configured such that the other end of the rotatable driving member (the end on the side not engaged with the blade group) is driven by the biasing force of a spring member. It is arranged on the main plate. Further, on the side where the other end of the driving member runs, the movable portion of the electromagnetic actuator is linearly reciprocated. With this configuration, project from the electromagnetic actuator (forward)
In a case where the movable portion is maintained in the state where the movable member is kept, the other end of the driving member can be locked at the tip of the movable portion. Also,
When the locking of the driving member is released, when the movable portion is retracted, the other end of the driving member is rotated by the urging force of the spring member so as to follow the retraction of the movable portion. Accordingly, the locking and unlocking of the driving member can be appropriately performed by the electromagnetic actuator, and the necessity of using an electromagnet is eliminated, so that the driving member is resistant to dust, oil, water droplets, and the like, and the quality of the shutter is improved. . It is also possible to return the driving member to the set position by projecting (moving forward) the movable portion of the electromagnetic actuator and rotating the other end of the driving member so as to push it back against the spring force.

[0007] In the focal plane shutter for a camera according to the second aspect, it is preferable that a hooking piece with which the movable portion is engaged is provided on the other end side of the driving member. When such a configuration is employed, when the driving member is locked or returned, the tip of the movable portion can be appropriately pressed against the driving member via the hooking piece.

According to a third aspect of the present invention, the electromagnetic actuator is preferably a linear DC motor having a coil portion on a stator and a magnet on a movable portion. Accordingly, even if the coil of the coil section is energized, the coil section does not move, so that the wiring can be easily performed and the disconnection of the lead wire connected to the coil is prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a focal plane shutter for a camera according to the present invention will be described below in detail with reference to the drawings.

As shown in FIG. 1, the focal plane shutter 1 has a shutter base plate 2 incorporated in a camera. The shutter base plate 2 is provided with an aperture 2a, which is a rectangular imaging opening, and a front blade group 3A that opens and closes the aperture 2a is attached via a front blade arm 5 that rotates about a support shaft 6. I have. The shutter base plate 2 is provided with a driving lever (driving member) 8 for the leading blade that rotates about a support shaft 7, and the leading end of the driving lever 8 is connected to the leading blade arm 5 via an operating pin 9. Have been.

Further, the tip of the driving lever 8 is connected to the spring member 1.
It runs in a clockwise direction (arrow A direction) on the drawing by 0 to rotate. Specifically, the spring member 10
Is composed of a tension spring and one end of the drive lever 8
, And the other end is fixed to the shutter base plate 2. Therefore, when the drive lever 8 is rotated by the force of the spring member 10, the front blade group 3A shifts from the closed state (see FIG. 1) to the open state (see FIG. 2).

Further, the shutter base plate 2 is provided with an electromagnetic actuator 12 having a rod (movable part) 11 which reciprocates linearly.
The rod 11 is fixed at a position where it engages with the drive lever 8. A hook 13 protruding in the radial direction is integrally formed at the other end (end) of the drive lever 8, and the rod 11 is engaged with the hook 13.

The electromagnetic actuator 12 is arranged on the side on which the hook 13 runs due to the urging force of the spring member 10 (above the hook 13 in the drawing). In addition to the engagement, the hook 13 is configured to reciprocate linearly on the running side. Therefore, by projecting (advancing) the rod 11 as shown in FIG.
3 can be locked, whereby the driving lever 8 can maintain the locked state, and the front blade group 3A can be maintained in the closed state.

On the other hand, when the locking state of the drive lever 8 is released, when the rod 11 of the electromagnetic actuator 12 is retracted, the drive lever 8 follows the retraction of the rod 11 by the urging force of the spring member 10. Hook piece 1
3 will rotate. Thereby, the drive lever 8
Is released, and the front blade group 3A can be brought into the open state. In this case, if the drive lever 8 is rotated by the spring member 10 after the rod 11 is retracted, friction between the rod 11 and the hook 13 of the drive lever 8 can be eliminated, and the rod 11 and the hook 13 can be reduced.

As described above, the locking and unlocking of the drive lever 8 can be properly performed by the electromagnetic actuator 12, and the use of an electromagnet is not required. Thus, the quality of the shutter 1 is improved.

The rod 1 of the electromagnetic actuator 12
1 is protruded (moved forward), and the hook 13 of the drive lever 8 is pushed back against the urging force of the spring member 10, whereby the drive lever 8 can be returned to the set position (FIG. 1).
reference).

Here, the aforementioned electromagnetic actuator 12
Will be described.

The electromagnetic actuator 12 is a linear DC motor and has a stator 23. The stator 23 has a cylindrical yoke 24 and a cup-shaped bobbin 26 which is disposed inside the yoke 24 and has a coil 25 wound thereon. Is formed. The bobbin 26 is provided with a linear guide portion 28 extending in the axial direction of the bobbin 26.

In such a stator 23, the rod 11
Are reciprocally accommodated. The rod 11 is made of a columnar permanent magnet, and is disposed inside the bobbin 26 at a predetermined interval. A guide hole 11a extending in the axial direction is formed in the rod 11, and a linear guide portion 28 is fitted into the guide hole 11a so as to be linearly movable.

In such a linear DC motor 12, when, for example, the coil 25 is energized in the forward direction by an electric signal from a control system (not shown) inside the camera, the rod 11 contracts (retreats) with respect to the stator 23. And coil 25
Are energized in the opposite direction, the rod 11 extends (projects) with respect to the stator 23. At this time, since the coil 25 is provided on the stator 23 side, the coil 25 does not move even when energized. Therefore, the wiring of the coil 25 can be easily performed, and the disconnection of the electric lead wire connected to the coil 25 can be prevented.
Is improved. Further, since the linear guide portion 28 is provided on the stator 24, the rod 11 moves smoothly and linearly.

By expanding and contracting the rod 11 of the linear DC motor 12 as described above, the front blade group 3A can be opened or closed via the drive lever 8. When the locking and release of the drive lever 8 is performed by the linear DC motor 12, which is an example of the electromagnetic actuator 12, the use of an electromagnet is not required, and the drive lever 8 becomes strong against dust, oil, water droplets, and the like. Exposure, underexposure, and overexposure are prevented, whereby the quality of the shutter 1 is improved. Further, since there is no need to provide a dustproof member or the like, cost reduction can be achieved. Further, since there is no need for a special environment such as a clean room in the assembly line, capital investment can be minimized, and cost reduction can be achieved in this regard.

Next, the rear blade group 3B for opening and closing the aperture 2a will be described with reference to FIGS. 4 and 5.
The opening and closing mechanism of the rear blade group 3B is substantially the same as that of the front blade group 3A. Note that the leading blade group 3A and the trailing blade group 3B
Although shown separately, it goes without saying that they are integrated into the shutter base plate 2.

A rear blade group 3B that opens and closes the aperture 2a is attached to the shutter base plate 2 via a rear blade arm 35 that rotates about a support shaft 36. The shutter base plate 2 is provided with a front blade drive lever (drive member) 38 that rotates about a support shaft 37, and the leading end of the drive lever 38 is connected to the rear blade arm 35 via an operation pin 39. Have been.

Further, the tip of the drive lever 38 is urged in a clockwise direction (the direction of arrow B) in the drawing by a spring member 40 composed of a tension spring so as to rotate.
Specifically, one end of the spring member 40 is fixed near the tip of the drive lever 38, and the other end is fixed to the shutter base plate 2. Therefore, the drive lever 38 is driven by the force of the spring member 40.
Is rotated, the rear blade group 3B shifts from the open state (see FIG. 4) to the closed state (see FIG. 5).

Further, the shutter base plate 2 is provided with an electromagnetic actuator 42 having a rod (movable portion) 41 which reciprocates linearly.
The rod 41 is fixed at a position where it is engaged with the drive lever 38. At the other end (end) of the drive lever 38, a hook 43 protruding in the radial direction is integrally formed, and the rod 41 is engaged with the hook 43.

The electromagnetic actuator 42 is disposed on the side on which the hook 43 runs due to the urging force of the spring member 40 (above the hook 43 in the drawing), and the rod 41 of the electromagnetic actuator 42 is attached to the hook 43. At the same time, the hook piece 43 reciprocates linearly on the running side. Therefore, by projecting (advancing) the rod 41 as shown in FIG.
3 can be locked, whereby the drive lever 38 can maintain the locked state and the rear blade group 3B can be maintained in the open state.

On the other hand, when releasing the locked state of the drive lever 38, the rod 41 of the electromagnetic actuator 42 is used.
Is retracted, the hook 43 of the drive lever 38 is rotated by the urging force of the spring member 40 so as to follow the retraction of the rod 41. Thus, the locked state of the drive lever 38 is released, and the rear blade group 3B can be closed. In this case, if the drive lever 38 is rotated by the spring member 40 after the rod 41 is retracted, friction between the rod 41 and the hook 43 of the drive lever 38 can be eliminated, and the rod 41 and the hook 43
Can be reduced.

Here, the rod 41 of the electromagnetic actuator 42 is protruded (moved forward), and the hook 4
By pushing back 3 against the urging force of spring member 40, drive lever 38 can be returned to the set position (see FIG. 4). The electromagnetic actuator 12 described above
And 42 have the same configuration, and a description thereof will be omitted.

The present invention is not limited to the above-described embodiment, but includes the support shaft 7 of the drive lever 8 and the leading blade arm 5.
Needless to say, the support shaft 6 may be arranged concentrically. Similarly, the support shaft 36 of the rear blade arm 35 and the support shaft 37 of the drive lever 38 may be arranged concentrically. Further, as a measure for returning the drive lever 8 to the set position, although not shown, a known set lever may be engaged with the drive lever 8 and the set lever may be rotated by a motor. The same applies to the drive lever 38.

[0030]

Since the focal plane shutter for a camera according to the present invention is constructed as described above, the following effects can be obtained. That is, a shutter base plate having a shooting opening, a blade group that opens and closes the shooting opening, a driving member rotatably attached to the shutter base plate, and one end of which engages with the blade group, and biases the driving member. The spring member and the shutter base plate are arranged on the side where the other end of the drive member runs by the biasing force of the spring member, and engage with the other end side of the drive member and linearly reciprocate on the side where the other end runs. With the provision of the electromagnetic actuator having the movable part, the quality can be improved and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of a focal plane shutter for a camera according to the present invention, showing a state in which an aperture is closed by a front blade group.

FIG. 2 is a front view showing a state where an aperture is opened by a front blade group.

FIG. 3 is a cross-sectional view illustrating an example of an electromagnetic actuator.

FIG. 4 is a front view showing a state where an aperture is opened by a rear blade group.

FIG. 5 is a front view showing a state where an aperture is closed by a rear blade group.

[Explanation of symbols]

1: Focal plane shutter, 2: Shutter base plate, 2:
a: aperture (aperture for photographing), 3A, 3B: feather group,
8, 38: drive lever (drive member), 10, 40: spring member, 11, 41: rod (movable part), 12: electromagnetic actuator, 13, 43: hook piece (other end), 23: stator, S: coil part.

Claims (3)

[Claims] A shutter base plate having a shooting opening; a blade group that opens and closes the shooting opening; a driving member rotatably attached to the shutter base plate and one end of which engages with the blade group; A spring member for urging the driving member, and on the shutter base plate, the other end of the driving member is arranged on a side on which the other end of the driving member runs by the urging force of the spring member, and is engaged with the other end side of the driving member. A focal plane shutter for a camera, comprising: an electromagnetic actuator having a movable portion that linearly reciprocates on the side on which the other end runs. 2. The focal plane shutter for a camera according to claim 1, wherein a hook piece with which the movable portion is engaged is provided on the other end side of the driving member. 3. The focal plane shutter for a camera according to claim 1, wherein the electromagnetic actuator is a linear DC motor having a coil portion on a stator and a magnet on the movable portion.