JPH0545659U - Focal plane shutter - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the blades from colliding with the intermediate partition plate or the like even when the blades are traveling at high speed. [Structure] An aperture 6 of an intermediate partition plate 5 is formed by expanding a lower edge 6a and an upper edge 6b, which are located in a direction orthogonal to the blade traveling direction, while inclining them in a substantially V shape. A notch groove 6c extending in the blade traveling direction is formed near the apex of the V-shape of the lower edge 6a. In order to prevent light leakage from the cutout groove 6c, an auxiliary shield member 19 having an upper edge along the lower edge 6a of the aperture 6 is provided between the front blade group 7 and the intermediate partition plate 5.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a blade collision prevention mechanism for a focal plane shutter for a camera.

[Prior Art]

In a focal plane shutter of a camera, the front blade group and the rear blade group are partitioned by an intermediate partition plate, so that an operating space for each blade group is secured. However, due to insufficient rigidity and strength of the blades, the blades may bend during braking. In such a case, during the operation of the blade, the blade may bulge in the optical axis direction due to the deflection of the blade and further vibration, and the blade may collide with the edge of the aperture of the intermediate partition plate. Conventionally, there are the following means for preventing the blade from colliding with the edge of the aperture.

First, in Japanese Patent Laid-Open No. 58-217919, in order to guide the travel of the slit blade when the blade is opened and closed, a stepped recess having the same width as the aperture frame is deeply formed in the partition plate. .. However, in this structure, since the recess is formed deeper than the amount of penetration when the slit blade is deployed, it is not possible to quickly suppress the inertia and bouncing of the slit blade. If the thickness is larger than the thickness of the partition, there is a problem that the blade collides with the edge of the aperture of the partition plate beyond the recess. Further, in Japanese Utility Model Laid-Open No. 3-47525, the intermediate partition plate is formed by bending the vicinity of the slit blade development position in the optical path direction. However, in this case as well, the inertia and bouncing of the blades cannot be suppressed quickly, and if the blades have a large deflection, there is a problem in that the blades cross the bent portion and collide with the edge of the aperture.

As another means, in order to reduce the collision of the intermediate partition plate with the edge of the aperture due to the deflection of the blade, the edge of the pair of apertures in the direction orthogonal to the traveling direction of the blade is V-shaped. There is one that is formed by unfolding and inclining. An example of such a conventional technique is disclosed in Japanese Patent Laid-Open No. 56-125726. In this invention, a slit is formed on the V-shaped edge of the aperture. This is an escape groove for the shaft that pivotally attaches the blades other than the slit blade to the support arm, and prevents the slit blade from colliding. Does not contribute to.

[0005]

[Problems to be solved by the device]

 However, with respect to the aperture having such a V-shaped edge, in recent years, due to the increase in the speed of driving the blade, the deflection and vibration of the blade have become larger than ever, and thus the collision between the blade and the edge of the aperture has occurred. Has become difficult to alleviate. This will be described with reference to FIG. 6. The aperture 2 formed on the intermediate partition plate 1 is formed such that the upper and lower edges 2a and 2b thereof are inclined in a V shape. On the other hand, when the blade 3 having the deflection 3a travels from the upper direction to the lower direction for closing operation, for example, the deflection 3a portion of the blade slides while contacting the edge 2a inclined in a V shape. Thus, although the bulge is suppressed, when the blade traveling speed is increased, as shown in FIG. 6 (B), the blade 2 advances to the edge 2a at high speed and a collision occurs.

In this case, while the blades are flexing or vibrating, the blades are traveling at high speed along the V-shaped edge 2a of the intermediate partition plate 1, and even when the blades reach the vicinity of the apex of the edge 2a, the blades are not bent or vibrated. The blade 3 did not fit and collided with the vicinity of the top of the edge 2a of the aperture 2. Moreover, since composite materials such as carbon fibers are used as the material for the blades today, the strength of the material is such that even if the rigidity strength is improved, the bond between the fibers is weak, so even if there is a small collision, Are easily destroyed. Therefore, there was a problem that the blade 3 was damaged due to the collision with the edge of the aperture 2 of the intermediate partition plate 1.

In view of the above problems, it is an object of the present invention to provide a focal plane shutter capable of preventing the blade from being damaged due to the collision between the blade and the intermediate partition plate even during high speed driving. ..

[0008]

[Means for Solving the Problems]

 In the focal plane shutter for a camera according to the present invention, the traveling space of the leading blade group and the trailing blade group is partitioned by an intermediate partitioning member having an aperture formed in the photographing optical path portion, and is substantially orthogonal to the traveling direction of the aperture blade group. In a focal plane shutter in which a pair of edges in the direction of the V-shape are spread in a substantially V-shape, the blades extend in the vane group traveling direction at the apex of at least one of the V-shape edges. It is characterized in that a groove is formed.

[0009]

[Action]

 When a pair of blades travels during shooting, if the blades are deflected or vibrate, for example, the slit blade of one blade comes into contact with the V-shaped edge of the aperture. Therefore, when the vehicle runs while being pressed along it, and when it reaches the vicinity of the apex of the V-shaped edge, this flexure further moves along the groove, so that the flexure is guided by the groove and bulges due to vibration. Is further corrected and collision between the edge and the blade can be avoided.

[0010]

【Example】

 A preferred embodiment of the present invention will be described below with reference to FIGS. 1 is a front view of a main part of the focal plane shutter as viewed from the rear blade group direction, FIG. 2 is a side view of FIG. 1 in which each member is simplified, and FIG. 3 omits the front blade group. It is a figure similar to.

In these figures, 5 is an intermediate partition plate having an aperture 6 for a photographing optical path formed in the center, and 7 is arranged on one side of the intermediate partition plate 6 and has, for example, 5 blades. Is a blade holding plate of the leading blade group 7, and 9 is a substrate attached to a camera body (not shown) adjacent to the blade holding plate 8. Further, 10 is a rear blade group which is arranged on the side opposite to the front blade group 7 with respect to the intermediate partition plate 5 and is composed of, for example, 5 blades, 11 is a blade pressing plate of the rear blade group 10, 12 Is a cover plate arranged to cover the rear blade group 10 with respect to the blade pressing plate 11. In addition, it is assumed that the blade pressing plates 8 and 11, the substrate 9 and the cover plate 12 are each formed with an opening (not shown) similar to the aperture 6.

Reference numeral 15 denotes a rotatable support arm, one end of which is pivotally attached to the base plate 9 by a base shaft 14 and pivotally supports one end of each of the blades 10 a, 10 b, 10 c, 10 d, 10 e of the rear blade group 10. The drive shaft of the rear blade group 10 slidably fitted in the guide hole 9a of the base plate 9 and pivotally attached to the support arm 15, and 17 has one end pivotally attached to the base plate 9 of the rear blade group 10. It is an auxiliary support arm that pivotally supports one end of each blade 10a, 10b, 10c, 10d, 10e. By moving the drive shaft 16 back and forth along the guide shaft 9a by a drive source (not shown), the rear blade group 10 can be opened and closed with respect to the aperture 6 in the up and down directions. This blade drive mechanism is also arranged for the leading blade group 7 (see FIG. 1), but since it has the same configuration, its explanation is omitted. The above-mentioned configuration is the same as the conventional technique.

Next, in the aperture 6 of the intermediate partition plate 5 (see FIG. 4), the lower edge 6a and the upper edge 6b in the blade traveling direction are inclined so as to open the frame in a substantially V shape, and the upper edge The top of 6b is located in the center, but the top of the lower edge 6a is located to the left of the center. Both edges 6a and 6b prevent the blades from colliding with each other when the leading blade group 7 and the trailing blade group 10 travel, and when the blade deflection or vibration occurs, guide the traveling. Moreover, a notch groove 6c is formed near the top of the lower edge 6a downward in the blade traveling direction. The notch groove 6c is a blade collision preventing means when the V-shaped edge 6a cannot completely prevent the collision of the blade, and the groove 6c is a stop position when the slit blade 10a of the rear blade group 10 is deployed. It extends to.

By the way, the formation position of the notch groove 6c may be appropriately selected according to the bending position of the blade, and the V-shaped apex of the lower edge 6a is also determined accordingly. Since the deflection of the blade changes depending on various factors such as the material of the blade, the position where it is fitted to the support arms 15 and 17, and the shutter speed, the position of the cutout groove 6c depends on the camera model. The position where the blade bulge is large, that is, the position where the most collision can be prevented can be selected by an experiment or the like. Therefore, the position of the notch groove 6c and the position of the V-shaped top are not necessarily limited to those of this embodiment.

Reference numeral 19 denotes a substantially L-shaped auxiliary shielding member which is arranged between the front blade group 7 and the intermediate partition plate 5 and which prevents leakage of photographing light in the region of the cutout groove 6c (FIG. 5). (See FIG. 3), the lower arm 19a has an upper edge portion 19b formed along a substantially V-shaped contour corresponding to the lower edge 6a of the aperture 6 (see FIG. 3) so as to shield the notch groove 6c. There is.

Since the present embodiment is configured as described above, the leading blade group 7 is expanded to close the aperture 6 and the trailing blade group 10 is folded and retracted from the aperture 6 in the charged state. I am When the photographing is started from this state, the leading blade group 7 is gradually folded from the unfolded state and the trailing blade group 10 is unfolded to expand both blade groups 7 and 10 at high shutter speeds, for example. The slits formed by the slit blades 7a and 10a travel in the vertical direction to perform exposure. Further, at the time of low-speed shutter second, after the leading blade group 7 is folded, the trailing blade group 10 is deployed after a predetermined time has elapsed.

Here, when each blade of the trailing blade group 10 is deflected, it travels downward while bulging toward the intermediate partition plate 5 side in the optical axis direction. It is pressed against the lower edge 6a of the aperture 6 and slides along the V-shaped inclined edge of the lower edge 6a while suppressing the bulge. When the deflection or vibration of the blade 10a does not subside even when reaching the apex of the lower edge 6a due to high speed operation, the slit blade 10a is further guided by the notch groove 6c, so that the bulge is further suppressed. Will be done. Therefore, the lower edge 6a and the slit blade 10a do not violently collide with each other, the blade reaches the stop position, and the inertia and the bounce are suppressed.

Moreover, in the case of the present embodiment, since the notch groove 6c of the lower edge 6a of the aperture is shielded by the auxiliary shield member 19 in the optical path direction, there is no risk of light leakage. Moreover, the auxiliary shielding member 19 and the cutout groove 6c do not adversely affect the opening / closing operation of the leading blade group 7. It should be noted that collisions due to the deflection of the blades are not limited to the edges of the slit blades and the aperture, but also when shooting several frames per second, when the leading blade group 7 and the trailing blade group 10 are superposed, and when the leading blade group 7 has a bound. In this case, it may occur between the blades of the leading blade group 7 and the trailing blade group 10. However, due to the arrangement of the auxiliary shielding member 19, a certain distance is secured between the front blade group 7 and the rear blade group 10, so that this distance can also prevent both blade groups 7, 10 from colliding with each other. ..

As described above, in the present embodiment, even when the blade group is made to travel at an extremely high speed or a composite material such as carbon fiber is used as the material of the blade, the rear blade group 10 and particularly the slits are used. It is possible to reliably prevent a blade damage accident due to a collision between the blade 10a and the intermediate partition plate 5. In addition, it is possible to prevent light leakage in the cutout groove 6c and prevent collision between the front blade group 7 and the rear blade group 10 without adversely affecting the operation of the front blade group 7.

Although the cutout groove 6c is formed only in the lower edge 6a of the aperture 6 in the above-described embodiment, the cutout groove may be formed in the upper edge 6b.

[0021]

[Effect of the device]

 As described above, in the focal plane shutter for a camera according to the present invention, a groove that can guide the bent portion of the blade is formed in the blade traveling direction at the substantially V-shaped edge of the aperture of the intermediate partition plate, so that the blade can move at high speed. It is possible to prevent the blades from colliding with the intermediate partition plate even during traveling, and to prevent the blades from being damaged even when a composite material such as carbon fiber is used as the blade material.

[Brief description of drawings]

FIG. 1 is a front view of a main part of a focal plane shutter according to an embodiment of the present invention.

FIG. 2 is a side view of a principal part showing each member of the focal plane shutter of FIG. 1 in a linear shape.

FIG. 3 is a view similar to FIG. 1, in which a leading blade group and a driving mechanism therefor are omitted.

FIG. 4 is a front view of an intermediate partition plate.

FIG. 5 is a front view of an auxiliary shielding member.

6A and 6B are views showing a main part of a conventional focal plane shutter, in which FIG. 6A is a partial perspective view, and FIG.

[Explanation of symbols]

 5 Intermediate partition plate 6 Aperture 6a Lower edge 6b Upper edge 6c Notch groove 7 Leading blade group 10 Rear blade group 19 Auxiliary shielding member

Claims (1)

[Scope of utility model registration request] 1. A traveling space of a front blade group and a rear blade group is partitioned by an intermediate partition member having an aperture formed in a photographing optical path portion, and a pair of edge portions substantially orthogonal to a traveling direction of the blade group of the aperture. In each of the camera focal plane shutters, each of which extends in a substantially V shape and is inclined, at least one of the apexes of the substantially V shape of the pair of edges,
A focal plane shutter having a groove extending substantially in the traveling direction of the blade.