JPH0524907Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a holding mechanism for a focusing plate holder in a single-lens reflex camera in which the focusing plate can be replaced.

"Prior Art and its Problems" In high-end single-lens reflex cameras, various focusing plates are prepared and can be replaced according to the user's preference or subject. Conventionally, this focusing plate exchange mechanism has a rotating shaft installed at the lower rear of the prism sheet (base) that serves as the base of the pentaprism, and a focusing plate holder that holds the focusing plate is rotatably attached to this rotating shaft. was. A holder lock member is provided between the front part of the focusing plate holder and the prism sheet. When replacing the focus plate, the holder lock member is released, the focus plate holder is rotated downward, and the focus plate is replaced.

However, in this conventional focusing plate exchange mechanism, the prism sheet has a rotating shaft and the focusing plate holder is pivotally attached to this, so the focusing plate holder and prism sheet are separated, and the holder shaft, shaft mounting plate, etc. Requires parts. Therefore, both the number of parts and the ease of assembly are disadvantageous, and furthermore, the shape of the prism sheet formed from the resin material molded product becomes complicated, which increases the difficulty of mold construction.

``Purpose of the invention'' This invention is based on an awareness of the problem with the conventional holding mechanism of the focusing plate holder, and the present invention is based on an awareness of the problem with the holding mechanism of the conventional focusing plate holder. The purpose is to obtain a mechanism. Another object of the present invention is to provide a focusing plate holder holding mechanism that is easy to assemble and does not come off when the assembly is completed.

"Summary of the invention" The present invention provides a retaining bent part and a position regulating bent part at the rear of a focusing plate holder that holds a focusing plate, spaced apart in the width direction of the holder; The prism sheet that is to hold the holder has a stopper part located above the retaining bent part to prevent the focusing plate holder from coming off, and a stopper part located below the position regulating bent part to the normal fixing position of the focusing plate holder. and a holding part for determining the focusing plate holder, and the retaining bending part and the position regulating bending part of the focusing plate holder, and the stopper part and holding part of the prism sheet are set in a substantially vertical position when the focusing plate holder is assembled. When they are detachable from each other,
In the assembled state, the focusing plate holder can be rotated due to the engagement relationship between the position regulating bent part and the holding part, and the shape is such that they cannot be separated from each other due to the relationship between the retaining bent part and the stopper. There is.

This holding mechanism has no parts other than the focusing plate holder and the prism sheet, and the stopper part of the prism sheet is located only in the upper part of the focusing plate holder's retaining bent part, and the lower part of the prism sheet is located in the position regulating bent part. Since the holding portion of the prism sheet is located only at the center of the lens, the position of the focusing plate holder can be reliably regulated and its dislodgement can be reliably prevented.

``Embodiments of the invention'' The invention will be described below with reference to illustrated embodiments. FIG. 6 shows the positional relationship of each component of the focusing plate and focusing plate holder portion of a single-lens reflex camera. The light transmitted through the photographing lens 11 is reflected by the mirror 12 toward the viewfinder optical system 13.

The finder optical system 13 includes a focusing plate 14 and a pentaprism 10 that reverses the vertical and horizontal directions of the image on the focusing plate 14, and a focusing plate holder 15 that supports the focusing plate 14 and a prism sheet 16. is supported by That is, the pentaprism 10 is formed using this prism sheet 1.
6, and the focusing plate holder 15 is
With the structure of the present invention, this prism sheet 16
It is supported at the rear lower part of. Reference numeral 17 denotes a holder locking member for locking the focusing plate holder 15 in a normal position.

As shown in FIGS. 1 to 5, the focus plate holder 15 has position regulating bent portions (curled portions) 15a bent downward at the rear thereof and located at both ends in the width direction. A retaining bent portion (curled portion) 15b is similarly bent downward at the portion. The position regulating bent portion 15a has a vertical regulating surface 15c that faces substantially vertically in the normal mounting position.
and a horizontal regulating surface 15d (an extension of the lower surface of the focusing plate holder 15) facing substantially horizontally, and the retaining bent portion 15b has a simple arc shape, as shown in FIG.

On the other hand, a holder support wall 20 is formed hanging below the rear end of the prism sheet 16.
On this holder support wall 20, a holding portion 21 corresponding to the position regulating bent portion 15a of the focusing plate holder 15,
Stopper portion 22 corresponding to the retaining bent portion 15b
is formed.

The holding part 21 includes an open window 23 penetrating the holder support wall 20 and a holding surface 24 at the bottom of the open window 23.
It has The holding surface 24 is a vertical holding surface 2 corresponding to the vertical regulating surface 15c of the focusing plate holder 15.
4a and a horizontal holding surface 24b corresponding to the horizontal regulating surface 15d, and when the vertical holding surface 24a and the vertical regulating surface 15c are in close contact with each other, and the horizontal holding surface 24b and the horizontal regulating surface 15d are in close contact with each other, the focusing plate The holder 15 is held in the normal position.

However, this holding part 21 requires an open window 23 on the upper part of the holding surface 24 for engaging the position regulating bent part 15a. Therefore, when the focus plate holder 15 is rotated downward to replace the focus plate 14, the engagement between the position regulating bent portion 15a and the holding surface 24 is easily released.

Therefore, the present invention further includes the position regulating bent portion 15a.
and a stopper part 22, and unlike the holding part 21, the stopper part 22 has a stopper surface 22a located above the position regulating bent part 15a at a certain distance 1, The lower part of the surface 22a is open.

In the present focusing plate holder holding mechanism having the above configuration, when assembling the focusing plate holder 15 to the prism sheet 16, the focusing plate holder 15 is placed in a vertical position or in the vicinity thereof, as shown by the symbol S in FIG. Set in the direction shown. Then, the holding portion 21 with which the position regulating bent portion 15a should be engaged
has an open window 23 at the upper part of the holding surface 24, so there is no hindrance to the movement in the direction A, and the tip of the retaining bent portion 15b is on the lower surface of the stopper surface 22a of the stopper portion 22. Get into it. After that, the focus plate 1 is placed on the focus plate holder 15.
4 and lift it up, the focusing plate 14 will be set in the correct position. In this set state,
As shown in FIG. 2, the vertical regulating surface 15c and the horizontal regulating surface 15d of the focusing plate holder 15 are respectively the vertical retaining surface 24a and the horizontal retaining surface 24b of the retaining surface 24.
The position of the focusing plate holder 15 is maintained correctly.

When the camera assembly is completed, focus plate holder 1
5 can only be rotated downward by an angle regulated by mirror 12. This angle is generally around 60°, and an example of this angle is shown by C in FIG. In this state, that is, when replacing the focus plate 14 on the focus plate holder 15, the focus plate holder 1
The retaining bent portion 15b of No. 5 is inserted into the lower surface of the stopper surface 22a of the stopper portion 22, and the focusing plate holder 15 cannot be removed from the holder support wall 20.

In other words, the length and curvature of the retaining bending portion 15b and the length and curvature of the stopper surface 22a of the stopper portion 22 are such that the length and curvature of the stopper surface 22a of the stopper portion 22 do not interfere with the assembly of both at the S position in FIG. This is done so that the bent portion 15b does not come off the stopper portion 22.

After replacing the focus plate 14, rotate the focus plate holder 15 upward and fix it with the holder lock member 17, and the state shown in FIGS. Retained.

"Effects of the invention" As described above, the focusing plate holding mechanism of the SLR camera of the present invention consists of only the prism sheet and the focusing plate holder, and there are no other components, so the number of parts is reduced. few. By means of the retaining bent portion and the position regulating bent portion formed on the focusing plate holder, and the corresponding stopper portion and holding portion formed on the prism sheet,
Since it is possible to securely hold the focus plate in the correct position and prevent it from coming off when replacing the focus plate, a focus plate holder with a simple structure and easy assembly can be obtained. Furthermore, since there is no need to attach a shaft holding plate to the prism sheet, the shape of the prism sheet can be simplified and the cost of the mold can also be reduced.

[Brief explanation of the drawing]

The figures show an embodiment of the holding mechanism for the focus plate holder of a single-lens reflex camera according to the present invention. The cross-sectional view, Figure 4, shows the assembled state and the state when the focus plate is replaced.
A sectional view similar to the figure, FIG. 5 is a view taken along the V arrow in FIG. 6,
FIG. 6 is a side view of essential parts showing the entire structure around the focus plate holder. 13...Finder optical system, 14...Focus plate, 15...Focus plate holder, 15...Position regulating bending part, 15b...Keeping bending part, 15c...
Vertical regulation surface, 15d... Horizontal regulation surface, 16... Prism sheet, 17... Holder lock member, 20
...Holder support wall (prism sheet), 21...
Holding part, 22...stopper part, 22a...stopper surface, 23...open window, 24...holding surface.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) At the rear of the focus plate holder that holds the focus plate of a single-lens reflex camera, a retaining bent part and a position regulating bent part are provided at a distance in the width direction of the holder. Each of the prism sheets is bent to support the pentaprism located above the focusing plate, and the stopper portion is located above the bending portion to prevent the focusing plate holder from coming off, and A holding part is formed in contact with the lower part of the position regulating bent part of the focusing plate holder and determines the holding position of the focusing plate holder, and the retaining part of the focusing plate holder, the position regulating bent part, and the prism The stopper part and the holding part of the seat can be engaged with and removed from each other when the focus plate holder is placed in a substantially vertical position during assembly.On the other hand, when the assembly is completed, the focus plate holder can be engaged with the holding part due to the engagement between the position regulating bending part and the holding part. A holding mechanism for a focusing plate holder for a single-lens reflex camera, characterized in that the plate holder is rotatable and has a shape that prevents it from separating from the other due to the relationship between the retaining bent part and the stopper. (2) In claim 1, the focusing plate holder retaining bending part and the corresponding stopper part of the prism sheet are provided at the center of the focusing plate holder in the width direction, and the same position regulating bending part and the corresponding stopper part are provided at the center of the focusing plate holder in the width direction. The holding portion is a holding mechanism for a focus plate holder of a single-lens reflex camera, which is provided at both ends of the focus plate holder in the width direction.