JPS6210751Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to, for example, an operating mechanism for a light-shielding plate that closes the transmission hole of a reflective mirror for a single-lens reflex camera, which is partially provided with a transmission hole for light guiding.

Conventionally, in single-lens reflex cameras equipped with an automatic distance measurement mechanism, a part of the reflecting mirror has a
A through hole is provided to guide a part of the luminous flux incident through the photographing lens to a distance measuring element, and the distance is measured using the light passing through the through hole.Then, during photographing, the through hole is blocked. A device that closes the mirror is disclosed in, for example, Japanese Patent Application Laid-Open No. 12626/1983, but due to the mechanism for raising the reflecting mirror in such conventional single-lens reflex cameras, variations in component parts, etc. Top dead center (the highest point)
If the member that controls the opening and closing of the light shielding plate depending on the relative position of the mirror system and the stopper is a fixed position stopper, the light shielding plate may not close completely due to variations in the top dead center, or the mirror lifting mechanism may It causes the phenomenon of biting between the stoppers.

Furthermore, when the opening and closing of the light shielding member is controlled by a rigid stopper, the mirror system on which the light shielding member is disposed collides with the stopper at high speed, so that the stopper absorbs the kinetic energy of the mirror system in a short time. The absorbed kinetic energy is converted into sound energy and thermal energy at the time of collision, and work energy that causes wear between the light shielding member and the stopper at the time of collision. When the opening and closing of the mirror system is controlled by a rigid stopper, the conversion of energy is performed in a short time, so the proportion of sound energy and work energy in the conversion of kinetic energy into sound energy, heat energy, and work energy is high. However, there were problems such as a loud collision noise and severe wear on the stopper and light shielding members.

The present invention has been made to solve these conventional problems, and has a structure in which the top dead center of the mirror system and the position of the stopper can be adjusted to optimize the closed state of the light shielding plate. To give elasticity to the stopper and reduce the rate of conversion into sound energy and work energy, so that the time for kinetic energy to be converted into sound energy, heat energy, and work energy when the mirror system collides with the stopper is longer. The object of the present invention is to provide a mechanism for operating a light shielding plate.

The present invention will be explained in detail below based on embodiments shown in the drawings.

1 is a photographing lens, and 2 is a main mirror for reflecting the light flux incident through the photographic lens 1 onto the focusing glass 3. On the back of this main mirror 2, a part of the light flux is reflected by a sub-mirror 4. A receiving plate 5 having an opening 5a for guiding light is attached.
Reference numeral 6 denotes a dividing prism that enters and divides the light reflected by the sub-mirror 4, and this dividing prism 6 has a distance measuring element 6b arranged at a position optically conjugate with the film 7 and its Distance measuring elements 6a and 6c are provided at positions approximately equidistant from each other in the front and rear. Note that such distance measuring elements 6a, 6b, 6
A focus detection device using the arrangement c is disclosed, for example, in Japanese Unexamined Patent Application Publication No. 155308/1983 filed by the applicant of the present invention. 8a and 8b are the leading and trailing curtains of a known focal plane shutter;
Reference numeral 9 denotes a sub-mirror receiving plate to which the sub-mirror 4 is adhesively fixed, and this receiving plate 9 is rotatably supported about a support shaft 9'. 10 is a main mirror arm driven by a mirror drive member (not shown);
This main mirror arm 10 is rotatably held around a support shaft 11 as a fulcrum. 12 is a support shaft fixed to the main mirror arm 10 and holds a spring 13; 14 is a light shielding plate rotatably supported via a support shaft 14' attached to the main mirror arm 10; The light shielding plate 14 is a light shielding plate that does not prevent the light flux passing through the opening 5a from entering the sub mirror 4 during observation, and closes the opening 5a during photography. The light shielding plate 14 is biased in the direction of opening the aperture 5 a to maintain a state in which the light beam L is guided from the aperture 5 a of the receiving plate 5 to the sub mirror 4 . 15 is an eccentric protrusion for regulating the position of the main mirror; 16 is a cushioning rubber for softening the shock when the main mirror is suddenly returned to the observation position by a quick return mechanism (not shown) after photographing; It has a shock absorption mechanism with initial tension and an adjustment plate that can adjust the overall vertical position.
18 is a screw for adjusting the initial tension of the adjusting plate 17;
9 is a screw for fixing the vertical position of the adjustment plate 17; 2;
0 is a soft cushioning member that absorbs the impact together with the adjusting plate of the adjusting plate 17 when the main mirror is raised. 2
1 is a part of the camera body, 22 is an eccentric protrusion for adjusting the position of the sub-mirror, 23 is a pentaprism, and 24 is an eyepiece lens.

The configuration of this embodiment has been described above, and its operation will be described next. In FIG. 1, when observing an object through the pentaprism 23, the main mirror 2 and the sub mirror 4 are at the positions indicated by solid lines, and a part of the light beam that has passed through the photographic lens passes through the aperture 5a to the sub mirror 4. reflected by the distance measuring elements 6a, 6
b and 6c, distance measurement (focus detection) is performed, and the light beam reflected by the main mirror 2 can be observed via the focusing glass 3 and the prism 23. After this observation, when the shutter (not shown) is pushed, the main mirror 2 moves to the position shown by the dotted line with the support shaft 11 as the fulcrum, and the sub mirror 4 also moves to the position shown by the dotted line with the support shaft 9' as the fulcrum. , so as not to impede the incidence on the film 7. When the main mirror 2 moves to the position indicated by the dotted line, the end 14a of the light shielding plate 14, which is in an integral relationship with the main mirror 2, comes into contact with the locking part 17b of the adjustment plate 17, and this contact force Accordingly, the light shielding plate 14 rotates against the elastic force of the spring 13 and closes the opening edge 5a. However, the adjusting plate 17 in this embodiment
is the elongated hole 1 for mounting as shown in Figures 2 to 4.
7a, and is attached to the camera body 21 so that its position can be adjusted in the vertical direction, so that the timing of contact between the locking portion 17b and the end portion 14a of the light shielding plate 14 is adjusted to be optimal. can,
This has the effect that the opening 5a can be closed easily and reliably. In addition, in FIGS. 3 and 4, since the locking portion 17b is formed of a flexible elastic member, the locking portion 17b and the light shielding plate 14 are
The impact force that occurs when the camera comes into contact with the camera is absorbed, thereby preventing wear and damage to the members, and furthermore, the shock caused by a collision is halved, making it possible to take good pictures without camera shake or the like. Furthermore, in Figure 4,
Since the screw 18 for adjusting the initial tension is screwed onto the locking portion 17b, which is a flexible elastic member, according to this embodiment, the action of the screw 18 causes slight plastic deformation of the flexible elastic member. In addition to absorbing the impact, the rigidity of the flexible member can also be adjusted, so even if repeated shocks are applied to this flexible elastic member, the standby position as a stopper will not change, and the impact force can be further reduced. There are other effects.

[Brief explanation of the drawing]

The drawings all show an embodiment of the light-shielding plate operating mechanism according to the present invention, and Fig. 1 is an explanatory diagram of the main parts of a camera equipped with the light-shielding plate operating mechanism, and Fig. 2 only shows the same upper and lower position adjustment mechanism. Partial diagram showing 3rd
The figure is a partial view of another embodiment in which a shock absorption mechanism has been added to the one in Figure 2, and Figure 4 is a partial view of another embodiment of the one in Figure 3, with initial tension added using screws and the initial tension value made variable. FIG. 7 is a partial diagram showing still another embodiment. 1... Photographing lens, 2... Main mirror, 3... Focusing glass, 4... Secondary mirror, 5... Receiving plate, 5a
...Aperture, 6...Division prism, 6a, 6b,
6c...Distance measuring element, 7...Film, 8a...
Front curtain, 8b...Rear curtain, 9...Sub-mirror receiving plate, 10
... Main mirror arm, 11 ... Support shaft, 12 ... Support shaft, 13 ... Spring, 14 ... Light shielding plate, 15 ... Eccentric protrusion, 16 ... Buffer rubber, 17 ... Adjustment plate, 1
8... Adjustment screw, 19... Screw, 20... Soft cushioning member, 21... Camera body, 22... Eccentric protrusion, 23... Pentaprism, 24... Eyepiece.

Claims (1)

[Scope of utility model registration request] The main movable mirror is rotatably supported at a viewfinder observation position and a photographing retreat position, and the main movable mirror is provided with an opening that transmits at least a part of the incident light beam and guides it backward. A light shielding plate is provided that is supported movably between a first position in which the opening is opened at the viewfinder observation position and a second position in which the opening is closed at the photography retreat position, and the light shielding plate is moved from the second position. The movable mirror is biased toward the first position by the spring biasing member, and the movable mirror comes into contact with the light shielding plate during rotation toward the photography retracted position, causing the light shielding plate to be biased by the spring biasing member. An adjustment plate is provided that moves the light shielding plate to the second position against the biasing force and holds the light shielding plate at the second position when the movable mirror completes rotation to the photographing retreat position. In the camera, the adjustment plate is mounted so as to be movable and adjustable in a direction substantially along a direction of movement of the main movable mirror to the photography retreat position so as to adjust the contact position with the light shielding plate, and further 1. An operating mechanism for a light shielding plate, characterized in that the adjusting plate is provided with a flexible elastic member at a contact portion with the light shielding plate in order to absorb impact force with the light shielding plate.