JPH06250263A - Finder mechanism for camera - Google Patents

Abstract

PURPOSE:To provide a mechanism in which a blacklash in an optical axial direction and a direction crossing it is not generated and having less components and, further, a simple structure in a finder mechanism capable of advancing or retracting two finder lenses. CONSTITUTION:This finder mechanism for a camera is provided with a guiding shaft 9 extended in the optical axial direction, two finder lenses 2 and 3 which have fitting parts 2a and 2b outside an optical axis O respectively and can be advanced or retracted and a coil spring 5 wound on the guiding shaft 9 between the finder lenses 2 and 3 and energizing them in the direction where they are separated each other and further, in the direction of around the guiding shaft 9. Moreover, the coil spring 5 is compressed in an axial direction and twisted by a prescribed angle to be assembled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a finder mechanism of a camera, and more particularly to a finder mechanism of a camera in which a finder lens can move forward and backward in the optical axis direction.

[0002]

2. Description of the Related Art Heretofore, various proposals have been made regarding a structure that enables highly accurate positioning of a finder lens in a finder mechanism of a camera having a structure in which a finder lens advances and retracts in the optical axis direction. For example, the finder mechanism of Japanese Patent Application No. 4-9535 previously proposed by the applicant is
As shown in FIG. 6, the forward / backward position accuracy of the two finder lenses L1 and L2 moving back and forth along the optical axis O of the finder optical system is improved.

That is, in the above mechanism, the finder lenses L1 and L2 are slidably supported by the guide rod 58 supported by the finder mechanism main body 59, and the detent pin 53 is provided at one end of each of the finder lenses L1 and L2. , 5
4 are integrally arranged. The detent pins 53, 54 are provided on the guide surface 55,
It is slidably fitted in the straight guide groove formed by 56. Further, drive pins 51 and 52 are integrally provided on the guide rod 58 support side of the finder lenses L1 and L2 so as to come into contact with and drive a lens drive cam (not shown). Then, the compression spring 63 is inserted into the guide rod 58, and is arranged in contact with the facing surfaces 61 and 62 of the supporting portions of the finder lenses L1 and L2, respectively.

In the conventional finder mechanism constructed as described above, the drive pins 51 and 52 of the finder lenses L1 and L2 are rotated with the pins 53 and 54 restricted by the grooves of the guide surfaces 55 and 56. The lens driving cam is abutted with the lens driving cam sandwiched from the outside, and is driven forward and backward. At that time, the compression spring 63 always makes the finder lenses L1 and L2
The lenses L1 and L
The play in the direction of the optical axis O of the finder 2 is absorbed and driven.

[0005]

However, in the finder mechanism of Japanese Patent Application No. 4-9535 mentioned above, the optical axis O
Although the play in the direction can be removed, the play around the guide rod 58 remains due to the component tolerance between the grooves of the guide surfaces 55 and 56 and the pins 53 and 54. Therefore, the lens L1, L
There was a possibility that vibration was generated around the axis in 2 and the field of view was shaken, and there was a possibility that the optical performance was deteriorated due to the shift of the lens center position.

The present invention has been made in order to solve the above-mentioned problems, and is a mechanism capable of removing play in the optical axis direction and the direction intersecting the optical axis when the two finder lenses are moved back and forth. With few components, and
An object of the present invention is to provide a finder mechanism of a camera having a simple structure.

[0007]

A finder mechanism for a camera according to the present invention has two guide rods that extend in the direction of the optical axis and fitting portions that fit with the guide rods are provided outside the optical axis. The finder lens and the finder lenses are wound around the guide rods and arranged to urge the finder lenses in a direction in which they are separated from each other and in a direction to rotate around the guide rods. And a coil spring for

[0008]

[Function] The finder lenses are urged by the coil spring in a direction in which they are separated from each other, and play in the optical axis direction is removed.
Furthermore, the finder lens is biased by the same spring in the direction of rotating around the guide rod to remove the play in the direction intersecting the optical axis.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a main part of a finder mechanism of a camera showing an embodiment of the present invention. 2 is a perspective view of a coil spring applied to the mechanism, and FIG. 3 is a layout view of the finder mechanism. The finder mechanism is applied as a zoom finder.

As shown in FIGS. 1 and 3, the present finder mechanism mainly comprises a finder support 11, a guide shaft 9 which is a guide rod fixed to the support 11, and a slidable guide shaft 9. The finder lens 2 is a concave lens and the finder lens 3 is a convex lens, which is supported by the, and the finder lens 3 is a convex lens, the coil spring 5 inserted into the guide shaft 9, and the lenses 2 and 3 are moved back and forth in the optical axis O direction. The cam members 10a and 10b of the cam member 10 are provided, and a guide groove 11a that is provided on the support 11 and restricts the rotation of the lenses 2 and 3 around the optical axis O.

The finder lenses 2 and 3 have supporting portions 2c and 3c located outside the optical axis, respectively, and fitting portions 2d and 3d arranged on the supporting portions 2c and 3c, respectively.
The guide shaft 9 is slidably fitted in 3d. The finder optical system includes the finder lenses 2 and 3 described above.
In addition, the roof mirror 12 and the prism 13, and the concave lenses 4 and the eyepieces 14 disposed behind the protective glasses 1 and 15 and the convex lens 3 shown in the longitudinal sectional views of the finder mechanism of FIGS. Composed of and.

Support part 2 for the finder lenses 2 and 3
Drive pins 2b and 3b are integrally provided on the lower portions of c and 3c so that they can contact the inner surfaces of the cams 10a and 10b of the cam member 10. Further, rotation stop pins 2a and 3a projecting in a direction orthogonal to the finder optical axis O are integrally provided with the finder lenses 2 and 3 at the opposite ends of the supporting portions 2c and 3c. The pins 2a and 3a are slidably fitted in the guide grooves 11a of the support 11.

The coil spring 5 has hook portions 5a, 5 at its end portion extending in the axial direction of coil winding as shown in FIG.
b. Then, this coil spring is mounted by inserting it into the guide shaft 9 and compressing the coil portion, and at the same time,
It is attached to the finder lenses 2 and 3 while being twisted in the winding direction. Therefore, the coil end of the coil spring 5 contacts and presses the inner surfaces of the supporting portions 2c and 3c of the lenses 2 and 3. The urging force F acts in the direction of separating the finder lenses 2 and 3. The driving pins 2b and 3 are driven by the urging force F.
Since b is pressed against the drive cams 10a and 10b, there is no backlash between the drive cams 10a and 10b and the drive pins 2b and 3b even if the lenses 2 and 3 move in the optical axis direction in this state. .

Further, as described above, the coil spring 5 is attached to the finder lenses 2 and 3 in a twisted state, and the hook portions 5a and 5b are respectively the supporting portions 2 of the lenses 2 and 3.
Since it is suspended and attached to the arms of c and 3c,
The lens 2 has a counterclockwise torque T with respect to the guide shaft 9.
And a clockwise torque T that opposes the above torque acts on the lens 3. Due to the torque T, the detent pin 2a comes into contact with the upper surface side of the guide groove 11a, and the detent pin 3a comes into pressure contact with the lower surface side of the guide groove 11a. Therefore, even if the lenses 2 and 3 move in the optical axis direction in this state, rattling around the guide shaft 9 of the lenses 2 and 3 does not occur.

FIGS. 4 and 5 are longitudinal sectional views showing a state in which the finder lenses 2 and 3 of the finder mechanism of this embodiment are advanced and retracted along the optical axis O. FIG. 4 is a wide zooming state, and FIG. 5 is a zooming state. Shows the tele state of. In the figure,
The point EP indicates an eyepoint.

When the above wide state is changed to the telephoto state, the driving positions of the finder lenses 2 and 3 are as follows: the distance D1 between the protective glass 1 and the lens 2, the distance D2 between the lenses 2 and 3,
The distance D3 between the lens 3 and the lens 4 changes as shown in FIGS. 4 and 5, and a finder image is observed at EP.

In the present embodiment, when the finder lenses 2 and 3 are moved, as described above, regarding the backlash in the optical axis O direction, the driving pin is driven by the urging force of the coil spring 5 in the F direction (see FIG. 2). 2b and 3b are removed by abutting and sliding on the cams 10a and 10b. Further, even if there is rattling around the guide shaft 9 that causes rattling in the direction intersecting the optical axis O of the finder lenses 2 and 3, the whirl-stopping force of the coil spring 5 causes the detent pins 2a and 3a to move up and down the guide groove 11a. It is removed by abutting against the inner surface and sliding. And the finder lens 2 and 3
Is the optical axis of each lens and the optical axis O of the finder optical system.
Move without breaking.

As described above, in the finder mechanism of the present embodiment, the optical axis O, which is the moving direction of the finder lenses 2 and 3, and the guide axis are rotated without increasing the number of parts and with a simple part structure. It eliminates sliding backlash and provides an accurate zooming finder image that can be observed with no field shake. The finder mechanism of the present embodiment is shown as an example applied to a zoom finder, but of course the present invention is not limited to this, and can be applied to other finder mechanisms having a structure for moving two or a plurality of finder lenses. Is.

[0019]

As described above, in the viewfinder mechanism of the camera of the present invention, the coil spring, which is interposed between the two viewfinder lenses, is biased in the direction in which the lenses are separated from each other, and at the same time, the lens is moved around the guide rod. By mounting so as to urge, play is removed in the optical axis direction of the lens and the direction intersecting the optical axis, without increasing the urging member.
Moreover, it is possible to provide a finder mechanism having a simple structure.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a finder mechanism of a camera according to an embodiment of the present invention.

FIG. 2 is a perspective view of a coil spring applied to the finder mechanism shown in FIG.

FIG. 3 is a layout view of the finder mechanism shown in FIG.

4 is a vertical sectional view of the finder mechanism shown in FIG. 1 in a wide state.

5 is a vertical cross-sectional view of the finder mechanism of FIG. 1 in a telescopic state.

FIG. 6 is an exploded perspective view of a conventional finder mechanism.

[Explanation of symbols]

 9 …………………… Guide shaft (guide rod) 2, 3 ……………… Finder lens 5 ……………… Coil spring 2d, 3d ……………… Mating part

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[Procedure amendment]

[Submission date] November 16, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

The finder lenses 2 and 3 have supporting portions 2c and 3c located outside the optical axis, respectively, and fitting portions 2d and 3d arranged on the supporting portions 2c and 3c, respectively.
The guide shaft 9 is slidably fitted in 3d. The finder optical system includes the finder lenses 2 and 3 described above.
In addition to the roof mirror 12, the prism 13, and FIG.
Protective glass 1,1 shown on the top of this finder mechanism
5 and a concave lens 4 arranged behind the convex lens 3, and an eyepiece
And the lens 14. The point EP in the figure is the eyepoi.
Indicates the event.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

FIGS. 4 and 5 are longitudinal sectional views showing the forward and backward states of the finder lenses 2 and 3 of the finder mechanism of this embodiment along the optical axis O, showing only the zoom optical system. 4 shows the zooming wide state, and FIG. 5 shows the zooming tele state.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 7

[Correction method] Added

[Correction content]

7 is a view showing a finder optical system of the finder mechanism shown in FIG.

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

[Figure 4]

[Procedure Amendment 5]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

[Procedure correction 6]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Added

[Correction content]

[Figure 7]

Claims (1)

[Claims] 1. A guide rod extending in the optical axis direction, two finder lenses each having a fitting portion for fitting with the guide rod outside the optical axis, and the guide between the finder lenses. A camera, which is wound around a rod and urges the finder lenses in a direction in which they are separated from each other, and a coil spring in a direction in which the finder lens is rotated around the guide rod. Finder.