JPH0725786Y2 - Focal plane shutter for camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a so-called vertical traveling type focal plane shutter for a camera that vertically moves a plurality of blades.

[Problems to be solved by conventional techniques and devices]

One of the conventional focal plane shutters of this type is, for example, as shown in FIG. 4, a shutter substrate 1 having an exposure opening 1a, and two pairs of arms 2 pivotally mounted near the exposure opening 1a of the shutter substrate 1. And a front blade group 5 and a rear blade group 6 each comprising a slit blade 3 and a plurality of cover blades 4 which are sequentially pivoted from the tip end portion to the base portion of each arm pair. The blade group 6 is configured to travel sequentially from top to bottom at time intervals corresponding to an appropriate exposure amount. A partition plate 7 (an opening designated as an exposure opening 1a) is provided between the two blade groups 5 and 6 so as not to collide with each other at the time of ending the exposure or setting the shutter to damage the blade or the arm. 7a) are provided. Therefore, there is a problem that the number of parts increases and the manufacturing cost increases.

Further, for example, in the focal plane shutter for a camera described in Japanese Utility Model Publication No. 35-19851, the slit blades of both blade groups are arranged closest to each other in the optical axis direction, and slit forming sides are provided at both ends of the slit blades. The partition plate has been omitted by providing an extension portion that extends to the first opening and does not overlap the exposed opening, and the extension portions are always overlapped with each other to prevent collision of both blade groups.

However, since the slit blade has the longest moving distance in each blade group, the driving force must be greatly increased in order to move the slit blade including the extension part within a predetermined time, and the driving force is If they are the same, there is a problem that the reduction in blade speed becomes large. Further, since the moving amount is large, the sliding length of the extension parts is also increased, so that there is a problem that the exposure becomes very unstable due to the influence of friction or the like. Further, since the slit blade is a blade that travels from one side of the exposure opening to the other side, if an extension portion is provided on this slit blade, the shutter substrate must be made large to allow it to escape, which leads to a compact camera. There was also the problem of becoming difficult.

In view of the above problems, the present invention has a low manufacturing cost, can minimize the decrease in the blade speed even when the driving force remains the same, can obtain stable exposure, and can easily make the camera compact. An object is to provide a focal plane shutter for a camera.

[Means and Actions for Solving the Problems]

The focal plane shutter for a camera according to the present invention is
A leading blade group including a shutter substrate, two pairs of arms pivotally mounted near the exposure opening of the shutter substrate, and a slit blade and a plurality of cover blades pivotally mounted sequentially from the tip to the base of each arm pair. In a focal plane shutter for a camera including a rear blade group, the cover blades pivotally mounted closest to the base ends of the arms of the both blade groups are disposed closest to each other in the optical axis direction. However, it is characterized in that extension portions extending toward the slit formation side and not overlapping the exposure opening are provided at both ends of the covering blades, and the extension portions are always overlapped with each other. That is, the blade provided with the extension is the cover blade pivotally mounted closest to the base end of the arm, and has the shortest moving distance in each blade group, so that the blade has the same driving force. The decrease in speed is the smallest, and the sliding length of the extension portions is also the shortest, so that the influence of the frictional force is extremely small, and it is not necessary to enlarge the shutter substrate to escape the extension portion.

In addition, according to the present invention, the shutter is inclined with respect to the edge of the slit blade so that the opposite edges of the cover blade provided with the extension can intersect at an angle.
This is what makes the covering blades less likely to collide.

Further, in the shutter of the present invention, the other blade mechanism is configured by simply turning the blade mechanism, which is composed of a pair of arms and a blade group, which is the same as one blade mechanism, inside out and attaching it to the shutter substrate. This is a reduction.

〔Example〕

The present invention will be described in detail below with reference to the same embodiment as shown in FIG.

FIG. 1 is a plan view showing a set state of an embodiment of the shutter of the present invention. In this embodiment, the cover blades 4, 4 pivotally attached to the arms 2 of the leading blade group 5 and the trailing blade group 6 closest to the base ends thereof.
The comrades are arranged closest to each other in the optical axis direction, and extension portions 4a and 4b that extend to the slit forming side and do not overlap the exposed opening 1a are provided at both ends of the covering blades 4 and 4 and the extension portions 4a and 4a. The comrades and the 4b, 4b comrades always overlap each other. Further, in the present embodiment, the edges 4c, 4c of the cover blades 4, 4 provided with the extension portions 4a and 4b are opposed to each other, so that the slit blades 3, 3 have edge portions 3a, 3c so that they can intersect obliquely. Inclined to 3a. Further, in this embodiment, the front blade mechanism including the same pair of arms 2, 2 and the front blade group 5 (slit blade 3 and the plurality of cover blades 4) is simply turned over and attached to the shutter substrate 1. It constitutes the mechanism.

Since the present embodiment is configured as described above, first from the set state shown in FIG. 1 (the front blade group 5 spreads to cover the exposure opening 1a and the rear blade group 6 is folded upward). The blade group 5 travels downward, is folded downward as shown in FIG. 2, opens the exposure opening 1a, and starts exposure. At this time, the traveling distance of the slit blade 3 is the longest and the extension 4a and
The traveling distance of the cover blade 4 having 4b is the shortest. Next, after a lapse of a predetermined time, the rear blade group 6 travels downward, spreads as shown in FIG. 3 to cover the exposure opening 1a, and the exposure is completed. Even at this time, the traveling distance of the slit blade 3 is the longest and the extension 4a and
The traveling distance of the cover blade 4 having 4b is the shortest.

Although the basic work of the present embodiment has been described above, the present embodiment is an extension portion that extends to the slit forming side at both ends of the cover blades 4, 4 that are closest to each other in the optical axis direction and does not overlap the exposure opening 1a. Since the extension portions 4a, 4a and the extension portions 4a, 4b and 4b, 4b are always overlapped with each other, the collision between the front blade group 5 and the rear blade group 6 is further prevented. Moreover, the blades 4 provided with the extension portions 4a and 4b,
4 is the cover blade 4,4 pivotally mounted closest to the base end of the arm 2,2 and has the shortest movement distance in each blade group, so the blade speed decreases even if the driving force remains the same. Can be the smallest. Further, the sliding length of the extension portions 4a, 4a and 4b, 4b is the shortest and the influence of the frictional force is extremely small, so that stable exposure can be obtained. Furthermore, the extension 4a
Since it is not necessary to increase the size of the shutter substrate 1 for escaping the shutters 4 and 4b, the camera can be easily made compact.

In addition, the edges 4c, 4c of the cover blades 4, 4 provided with the extension portions 4a, 4b are inclined with respect to the edges 3a, 3a of the slit blades 3, 3 so that they can intersect obliquely. Therefore, the collision between the front blade group 5 and the rear blade group 6 is prevented. Further, in this embodiment, the same pair of arms 2, 2 and leading blade group 5 are used.
Since the front blade mechanism including the slit blade 3 and the plurality of cover blades 4 is simply turned over and attached to the shutter substrate 1, the rear blade mechanism is configured, so that the manufacturing cost is further reduced.

[Effect of device]

As described above, the focal plane shutter for a camera according to the present invention has a low manufacturing cost, can minimize the decrease in the blade speed even when the driving force remains the same, and can obtain a stable exposure, and further downsize the camera. It has an important practical advantage of being easy.

[Brief description of drawings]

FIG. 1 is a plan view showing a shutter set state of an embodiment of a focal plane shutter for a camera of the present invention, FIGS. 2 and 3 are plan views showing an exposure state and an exposure end state of the above embodiment, respectively. FIG. 7 is a plan view showing a shutter set state of a conventional example. 1 ... Shutter substrate, 1a ... Exposure opening, 2 ... Arm,
3 ... Slit blade, 3a ... Edge, 4 ... Cover blade, 4
a, 4b …… extension part, 4c …… edge part, 5 …… front blade group, 6 ……
Rear blade group.

Claims (1)

[Scope of utility model registration request] 1. A shutter base plate, two pairs of arms pivotally mounted near an exposure opening of the shutter base plate, and a slit blade and a plurality of cover blades pivotally mounted sequentially from a tip portion to a base portion of each arm pair. In a focal plane shutter for a camera having a leading blade group and a trailing blade group, the covering blades pivotally mounted closest to the base ends of the arms of the both blade groups are the most in the optical axis direction. The camera focal point is characterized in that it is arranged in close proximity to each other, and both ends of the covering blades are provided with extensions that extend toward the slit formation side and do not overlap with the exposed opening, and the extensions are always overlapped with each other. Plain shutter.