JPS6323700Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a focus plate mounting device for a single-lens reflex camera, which is used in a single-lens reflex camera and allows the focus plate to be replaced.

Prior Art Recently, in single-lens reflex cameras, in order to clean dirt and debris on the focus plate, or to make it possible to use other types of focus plates, it is possible to clean the focus plate by inserting your hand through the opening in the front of the camera. In many cameras, the focus plate can be removed as appropriate even after assembly is completed. Most of the focus plate mounting devices that allow the focus plate to be removed in this way have a presser frame made of a leaf spring installed below the focus plate holder and supported by a hinge so as to be rotatable around the back of the camera. After the focus plate is inserted between the presser frame and the focus plate holder, the presser frame is locked to the fixed part of the camera, and this locking is done by inserting your finger through the opening on the front of the camera. It can be canceled as appropriate.

However, with this mounting device, an extra space is required behind the focusing plate of the camera in order to mount the hinge, which hinders miniaturization of the camera. Conventional single-lens reflex cameras have widely used a shutter device that exposes the film by running a shutter curtain wrapped around a cylindrical body installed on the left and right sides of the back of the camera. All that was needed was to leave enough space to ensure smooth running, and in that sense, even with the hinges installed, the camera could be kept relatively compact.
However, recent single-lens reflex cameras have come to use a unit shutter device in which the shutter blades and the mechanism that operates them are all mounted on a pair of base plates, and due to the arrangement of this shutter device, The space behind the camera is quite limited. Therefore, especially when such a shutter device is used, if the above-mentioned hinge is provided, a new space must be created at the back of the camera to avoid the space where the shutter device is placed, which makes it difficult to miniaturize the camera. It was a big hindrance.

Therefore, the rear end of the focus plate is elastically clamped from above and below by a clamping member, and the front end of the focus plate is held in the focus plate holder by a leaf spring that can be screwed and removed through the opening in the front of the camera. A focus plate mounting device has been proposed in which the focus plate can be attached and detached by making elastic contact with the lower surface of the focus plate and attaching and detaching a leaf spring. In this mounting device, since the holding member serves as a hinge, there is no need to provide a special space for arranging the hinge at the back of the camera, which can contribute to miniaturization of the camera.

However, in order to replace the focus plate, it was necessary to attach and detach the leaf spring that was screwed on, and the operation of attaching and detaching the screws was time-consuming. Moreover, since there is a gap between the reticle and the reticle holder, dust can sometimes enter through the gap.

Purpose The present invention provides a focusing plate mounting device that does not require a large space inside the camera, allows easy replacement of the focusing plate, and prevents dust from entering between the focusing plate and the focusing plate holder. It is intended to.

Summary The reticle mounting device of the present invention includes a reticle holder having a vertical inner wall surface that can be fitted to the outer peripheral end surface of the reticle and a horizontal lower surface that can come into contact with the upper surface of the edge of the reticle. The rear end portion is held between the lower surface of the reticle holder and the clamping member, while the front end portion of the reticle is held between the lower surface of the reticle holder and an elastic holding member that can be retracted from the holding position by elastic deformation. It is characterized by being twisted and held.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 4 show an embodiment of the present invention. In the exploded perspective view shown in FIG. 1, an opening is formed in the center of the front plate 2, and a mount member 4 for attaching an interchangeable lens is provided. A mirror box 8 with a movable mirror 6 is fixed to the rear surface of the front plate 2. A pentagonal prism holder 10 fixed to the upper end of the mirror box 8 has a focusing plate holder 12 inserted therein, and has a housing 10a for a spring 14 on its side wall, and an eyepiece window frame 16 on its rear wall. have. A focusing plate holder 12 to which a focusing plate 18 can be attached and removed is inserted into the pentaprism holder 10 with a gap formed between it and the inner wall of the pentaprism holder 10. The vertical position of the focus plate holder 12 can be adjusted by an adjustment mechanism using a spring 14, a plate 20, and a screw 22, which will be described in detail later. A polyurethane foam 24 is attached to the outer peripheral surface of the reticle holder 12 to compensate for the gap between the pentagonal prism holder 10 and the reticle holder 12.

Furthermore, above the focus plate holder 12 in the pentaprism holder 10, a prism support plate 26 forming a viewfinder field frame 26a is provided, and a pentaprism 30 is placed on this support plate 28.

As shown in an enlarged view in FIG. 2, the focusing plate 18 has a flange 32 projecting outward at the lower part of the outer peripheral end surface, and a mounting piece 32a and a knob 3 at the front end of the flange 32.
2b, a split image prism 18a is provided at the center of the upper surface, a microprism 18b is provided around the split image prism 18a, and a matte surface 18c is provided over the entire upper surface around the split image prism 18a. In addition, the focus plate holder 12
is an inner wall 12a into which a vertical end surface 18d located above the flange 32 of the outer circumferential surface of the focus screen 18 can be fitted.
and a peripheral wall having a lower end surface 12b on which the upper surface 32c of the flange 32 can abut, and a small diameter hole 12c that stands upward from the upper end surface of the peripheral wall and is bent at the upper end.
It has three mounting pieces 12d formed with. A support member 34 is provided on the rear surface of the peripheral wall, and has a support piece 34a that cooperates with the lower end surface 12b of the peripheral wall to clamp the rear end of the flange 32 of the focusing plate 18, and has the same length as the rear surface of the peripheral wall. An elastic holding piece 36a is attached to the front surface of the peripheral wall for elastically abutting the mounting piece 32a of the focusing plate 18 against the lower end surface of the peripheral wall.
A holding member 36 having the same length as the front surface of the peripheral wall is fixed. This holding member 36
is made of an elastic metal plate, and its holding piece 36a, which is bent into an L-shaped cross section, is attached to the slope 36.
an opening that receives the mounting piece 32a and a slope 36b that presses the mounting piece 32a upward.
The focus plate 18 is bent by elastic deformation and can be retracted from the position where the focus plate 18 is held.

Note that since the support member 34 and the holding member 36 each have a length from one end of the front wall or the rear wall of the reticle holder 12 to the other end, the reticle holder 12 cannot be moved in a state in which they are fixed. Steps are not formed in the outer circumferential direction of the front and rear walls. Therefore, no gap is created between the polyurethane foam 24 and the outer wall of the reticle holder 12.

FIG. 3 is a cross-sectional view of the reticle holder 12 and its surrounding members after assembly, viewed from the side. Between the inner wall of the pentaprism holder 10 and the outer wall of the reticle holder 12 is the polyurethane foam 2 described above.
4 without any gaps, dust does not enter from below into the viewfinder chamber formed by the focusing plate 18 and the pentagonal prism 30, and it is breathable.

The vertical end surface 18d of the focusing plate 18 is connected to the focusing plate holder 1.
It fits into the inner wall 12a of No. 2. The rear end of the focusing plate 18 is elastically pressed by the support piece 34a, while the front end of the focusing plate 18 is elastically pressed upward by the holding piece 36a and the slope 36b.
The focus plate 18 is configured such that the upper surface 32c of the flange 32 is in contact with the lower end surface 12b of the focus plate holder 12.
It is integrally attached to the focus plate holder 12.

From this state, when the knob 32b of the focus plate 18 is pulled downward, the focus plate 18 rotates counterclockwise in the figure around the rear end. Along with this, the mounting piece 32a pushes the slope 36b of the holding piece 36a downward, elastically deforms the holding piece 36a, overcomes the slope 36b, and is released from the holding piece 36a. Focus plate 1
8 from the holding piece 36a and then further rotated counterclockwise and pulled out forward, the engagement between the rear end and the supporting piece 34a can be disengaged, and as a result, the focus plate 18 can be attached to the camera. Through the front opening,
It can be taken out from the camera.

On the other hand, to attach a new focus plate 18 or a previously removed focus plate 18, the focus plate 18 is passed through the front opening of the camera, and the rear end of the focus plate 18 is connected to the support piece 34a and the lower end of the focus plate holder 12. After inserting the focus plate 18 between the focusing plates 18 and 18, the front end of the focus plate 18 is pushed upward while rotating around the rear end. As a result, the attachment piece 32a of the focusing plate 12 is attached to the holding piece 36a.
Push the lower slope 36c upward and hold the holding piece 36a.
is elastically deformed and pushed out of the rotation locus of the mounting piece 32a. After that, when the front end of the focusing plate 18 is further pushed upward, the mounting piece 32a is moved to the holding piece 36a.
, and the vertical end surface 18 of the reticle 18
d fits into the inner wall of the reticle holder 12, and the flange 32
The upper surface 32c is the lower end surface 12b of the focus plate holder 12.
comes into contact with. Along with this, the holding piece 36a returns to the holding position, and the upper surface 32c of the flange 32 of the focus plate 18 is attached to the lower end surface 12b of the focus plate holder 12.
The focus plate 18 is now brought into elastic pressure contact, and the attachment of the focusing plate 18 is completed.

FIG. 4 is a sectional view showing an adjustment mechanism provided in the pentagonal prism holder 10 for adjusting the position of the reticle holder 12 in the vertical direction. A pin 10b is provided in the storage portion 10a of the pentaprism holder 10.
A spring 14 is fitted around the outer periphery of the pin 10b. The bent upper end of the mounting piece 12d in the reticle holder 12 is placed on the upper end of the spring 14 and is elastically pressed upward, while
It is held down by a screw 22 engaged with the small diameter hole 12c. The screw 22 is screwed into a plate 20 fixed to the pentagonal prism holder 10, and can be adjusted to move vertically. Therefore, by moving and adjusting this screw 22 in the vertical direction, the position of the focusing plate holder 12 can be adjusted in the vertical direction.

In the focusing plate mounting device as described above, there is no need to attach or remove the mounting screws when attaching or removing the focusing plate 18.
Easy to put on and take off. Moreover, reticle holder 1
Since the reticle 2 and the reticle 18 abut each other on the horizontal and vertical surfaces over their entire circumferential wall, dust hardly enters from their mating points.
The position of the focus plate 18 with respect to the focus plate holder 12 can be determined reliably.

FIG. 5 shows the focusing plate 42 and the focusing plate holder 4.
As shown in the figure, a stepped portion consisting of a lower surface 44a and an inner wall surface 44b falling with respect to the lower surface 44a is formed at the lower end of the focusing plate holder 44, while the focusing plate 42 is An outer peripheral end surface 42a that can be fitted into the inner wall surface 44b of the plate holder is formed, and a lower surface 44a of the stepped portion of the focus plate holder 44 is formed.
Alternatively, the inner wall surface 44b, the outer peripheral upper surface 42b and the outer peripheral end surface 42a of the focusing plate 42 may be configured to abut each other.

Note that the holding piece that elastically presses the front end of the focusing screen against the lower surface of the focusing screen holder is an elastically deformable holding piece that has the same cross-sectional shape as the support piece 34a that supports the rear end of the focusing screen 18 in FIG. A possible plate member may be constructed, that is, simply a vertical portion formed along the reticle holder and a bent portion at the lower end of the tip. In this case, since the focus plate cannot be removed from the holding piece simply by pulling it downward, the holding piece is elastically deformed by hand or using a jig to be retracted from the holding position.

Effects The reticle mounting device of the present invention is easy to handle because the reticle can be attached and removed simply by elastically deforming the holding member of the reticle holder. Moreover, since the vertical end surface and the top surface of the outer circumferential portion of the reticle contact the inner wall surface and lower surface of the reticle holder, respectively, it is difficult for dust to enter from the fitting area, and the position of the reticle relative to the reticle holder is reduced. can be easily determined. Furthermore, since no hinge mechanism is used, there is no need for a large space at the back of the camera.

Further, as in the embodiment, if the holding member is provided with a focusing plate holding piece that protrudes from the focusing plate and has an inclined surface that the focusing plate can overcome by elastic deformation of the holding member, the focusing plate can be simply moved downward. Since it can be removed by simply pulling the focus plate, and it can be attached by simply pushing the focus plate upward, the focus plate can be replaced even more easily.

[Brief explanation of the drawing]

Figures 1 to 4 show an embodiment of the present invention. Figure 1 is an exploded perspective view showing a part of a camera to which the present invention is applied, and Figure 2 is a perspective view showing the main parts of the present invention. FIG. 3 is a cross-sectional view seen from the side after assembly, and FIG. 4 is a cross-sectional view showing the vertical position adjustment mechanism of the focus plate mounting device. FIG. 5 is a sectional view showing a modified embodiment. 12, 44... reticle holder, 18, 42...
Focal plate, 12a, 44b... Vertical inner wall surface, 12
b, 44a... horizontal lower surface, 18d, 42a... outer peripheral end surface, 32... flange, 32c, 42b... edge upper surface, 36... holding member, 36a... holding piece, 3
6b, 36c... Slanted surface.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. In a focus plate mounting device for a single-lens reflex camera in which the focus plate can be replaceably attached to a predetermined position in the camera body through an opening on the front surface of the camera body, Vertical inner wall surface to be mated,
and a reticle holder having a horizontal lower surface that abuts the upper edge of the reticle, a support member that supports the rear end of the reticle in cooperation with the horizontal lower surface, and a support member formed on the front end surface of the reticle. The mounting plate has an opening for receiving the mounting piece, and an upwardly inclined slope on the front side that cooperates with the horizontal lower surface to clamp the mounting piece by elastically pressing the mounting piece upward in the opening. A focus plate mounting device comprising: a holding member that is elastically deformable so that the engagement between the slope and the mounting piece is released when a downward external force of a predetermined amount or more is applied to the piece. 2. The reticle includes a flange that extends outward from the outer peripheral end surface and whose upper surface includes the upper edge surface, and the vertical inner wall surface and horizontal lower surface of the reticle holder are respectively connected to the outer peripheral end surface and the flange of the reticle. The focus plate mounting device according to claim 1, which is formed so as to come into contact with the upper surface of the edge of the reticle. 3. The focusing plate has a vertical outer circumferential end surface and an edge upper surface adjacent to the inner side thereof, and the focusing plate holder has a vertical inner wall surface and a horizontal lower surface that abut the outer circumferential edge surface and the edge upper surface of the focusing plate, respectively. A focusing plate mounting device according to claim 2 of the registered utility model.