JPH0514614U - Dowel for caulking of shutters for cameras - Google Patents

Abstract

(57) [Abstract] [Purpose] Effectively responding to higher shutter speeds and reducing distortion and cracking after caulking.
Provided is a dowel for caulking a shutter blade. [Structure] A portion of the second shaft portion 1e facing the caulking hole 3a of the shutter blade 3 is formed to have a rectangular cross section along the step portion 1c for receiving the shutter blade 3, which is slightly thicker than the thickness of the shutter blade 3. A groove 1f is provided for escape.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a crimping dowel for crimping a blade of a camera shutter.

[0002]

[Prior Art]

 FIG. 6 shows the structure of this type of conventional caulking dowel. In the figure, the dowel 11 has a flange portion 11a provided at one end and a first shaft portion 11b for pivotally supporting the arm 12. From a step portion 11c for receiving the shutter blade 13 formed on the first shaft portion 11b, and a second shaft portion 11e for crimping the shutter blade 13 formed around the recess 11d. Has become. When the dowel 11 thus formed is inserted into the hole 12a of the arm 12 and the caulking hole 13a of the shutter blade 13 and the second shaft portion 11e is pressed by a pressing means such as a chisel (not shown), The second shaft portion 11e expands outward, and the shutter blade 13 is sandwiched and fixed between the step portion 11c and the second shaft portion 11e (see FIG. 6B).

[0003]

[Problems to be solved by the device]

 In the above-mentioned prior art, as the second shaft portion 11e is expanded, stress is concentrated on the periphery of the caulking hole 13a of the shutter blade 13 which is in contact with the bent portion of the second shaft portion 11e, so that it is deeply crushed. It was supposed to be. Therefore, when a composite material made of carbon fiber or the like, which has begun to be used for increasing the shutter speed in recent years, is used as the shutter blade and the dowel 11 is caulked, there is a problem that the shutter blade is distorted or cracked. .

That is, in the case of a shutter blade formed of a composite material, if the peripheral edge of the caulking hole is crushed due to the stress concentration, it has high strength but poor malleability (ductility, malleability). However, the distortion may spread from the peripheral edge, or the shutter blade may be broken. On the other hand, if the caulking is weakened so that such cracks do not occur, the shutter blades and the dowels are loosely connected, and the shutter speed cannot be increased.

The present invention has been made in view of the above problems of the conventional technology, and an object thereof is to effectively cope with an increase in shutter speed and to prevent distortion and cracks after caulking. Another object of the present invention is to provide a dowel for the caulking of the shutter blade, which can reduce the occurrence of the above problem.

[0006]

[Means for Solving the Problems]

 The caulking dowel according to the present invention is formed in a portion of the second shaft portion opposite to the caulking hole of the shutter blade along the stepped portion for receiving the shutter blade and having a rectangular cross-section slightly thicker than the thickness of the shutter blade. A groove for escape is provided. Further, the crimping dowel according to the present invention can be suitably used in the focal plane shutter when crimping the cover blades other than the slit forming blades.

[0007]

[Action]

 According to the present invention, when caulking, the second shaft portion expands, and the contact surface of the shutter blade and the contact surface of the second shaft portion come into contact with each other, and then the shutter blade is contacted via the contact surface. Since pressure contact force is applied, the occurrence of strain due to stress concentration is prevented. Further, since the peripheral edge of the caulking hole and the shaft surface of the second shaft portion are slightly separated from each other, pressing the second shaft portion causes the peripheral edge of the caulking hole to become a dowel even if the caulking hole diameter changes. It does not interfere more than necessary, and it is possible to prevent deformation and cracking of the shutter blades due to such caulking.

[0008]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. 1 and 2 show a preferred embodiment of the present invention, in which 1 is a dowel for crimping according to the present invention, the dowel 1 having a collar portion 1a provided at one end and an arm. A first shaft portion 1b for pivoting the shutter 2, a step portion 1c for receiving the shutter blade 3 formed on the first shaft portion 1b, and a shutter blade 3 formed on the periphery of the recess 1d. And a second shaft portion 1e for crimping. A groove 1f for escape is formed along the stepped portion 1c at a portion of the second shaft portion 1e facing the caulking hole 3a of the shutter blade 3. In FIG. 2, the groove 1f is separated from the peripheral surface of the caulking hole 3a of the shutter blade 3 to be caulked by a slight amount d to the shaft surface of the second shaft portion 1e, and the plate of the shutter blade 3 is formed. It has a thickness (t + α) slightly larger than the thickness t and is formed in a rectangular cross section in the central direction of the shaft with respect to the shaft surface of the second shaft portion 1e.

Since the crimping dowel according to the present embodiment is configured as described above, when the second shaft portion 1e is pressed by a pressing means such as a chisel not shown, the second shaft portion 1e is removed. The shutter blades 3 are expanded toward one side, and the shutter blades 3 are clamped and fixed between the step portion 1c and the second shaft portion 1e (see FIG. 1B). At this time, since the width (t + α) of the groove 1f is formed larger than the plate thickness t of the shutter blade 3, the contact surface of the shutter blade 3 comes into contact with the contact surface of the expanded second shaft portion 1e. Then, pressure contact stress is applied to the shutter blade 3 from the second shaft portion 1e via the contact surface. Therefore, the stress is not concentrated on the periphery of the caulking hole 3a of the shutter blade 3, and the occurrence of distortion due to the stress concentration can be prevented. Furthermore, since the groove 1f is separated from the peripheral edge of the caulking hole 3a by a slight amount d with respect to the shaft surface of the second shaft portion 1e, the diameter of the caulking hole 3a can be reduced by pressing the second shaft portion 1e. Even when the change occurs, the peripheral edge of the caulking hole 3a does not interfere with the dowel 1 more than necessary, and the deformation or cracking of the shutter blade 3 due to caulking can be prevented.

The action and effect at the time of crimping work effectively even when the shutter blade 3 is made of a composite material. That is, as in the case of the conventional example, when a composite material, for example, carbon fiber is used as the blade member, the strength of the fiber is high, and therefore, when the tip of the fiber is crushed during crimping, the strain spreads from there, and the shutter blade is not cracked. However, according to the present embodiment, as described above, the stress is not concentrated on the peripheral edge of the caulking hole 3a, and the peripheral edge does not interfere with the dowel 1 more than necessary. In addition to being able to prevent deformation and cracking, it can be reliably clamped and fixed, and in a focal plane shutter using a composite material as a blade member, it is possible to effectively respond to an increase in shutter speed.

However, in the dowel 1 according to this embodiment, the diameter of the groove 1f is smaller than the diameter of the caulking hole 3a. Therefore, the shutter blade 3 is not always accurately positioned at the center of the shaft of the dowel 1 during crimping. Therefore, when particularly high exposure accuracy is required in the shutter blade assembly as shown in FIG. 3, the dowel 11 having the conventional structure is used for the slit forming blade 5 which has a great influence on the exposure accuracy, and the other. It is preferable to use the dowel 1 of the present embodiment for the cover blades 6 to 9 and perform the crimping with the arm 2.

FIG. 4 shows another embodiment of the present invention, the operation of which is the same as that of the above-mentioned embodiment, so the description thereof is omitted. However, as shown in the drawing, in order to reduce the height of the dowel after caulking, The taper 1g may be formed on the conical fir 1d 'of the second shaft portion 1e, or the dowel 1 may be hollow so as to reduce the weight of the dowel 1. Further, as shown in FIG. 5, the corners of the groove 1f may be formed by curved surfaces, as a matter of course.

[0013]

[Effect of the device]

 As described above, according to the present invention, the periphery of the caulking hole of the shutter blade is less likely to be crushed at the time of caulking, and it is possible to reliably prevent the blade from being distorted or cracked due to the caulking. Therefore, it is possible to effectively prevent the disadvantage that the blade is distorted due to the concentrated stress, especially the distortion and cracks that occur when the blade member formed of the composite material is caulked, so that the caulking is reliably performed and the shutter speed is high. In addition to effectively responding to this, it is possible to guarantee stable and low-loss blade travel.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of a caulking dowel according to the present invention, (A) showing a state before caulking and (B) showing a state after caulking.

FIG. 2 is an enlarged sectional view of an essential part for explaining the structure of a crimping dowel according to the present invention.

FIG. 3 is a plan view of a shutter blade group in an embodiment of a focal plane shutter using a caulking dowel according to the present invention.

4A and 4B are cross-sectional views of another embodiment of a caulking dowel according to the present invention, FIG. 4A showing a state before caulking, and FIG. 4B showing a state after caulking.

FIG. 5 is an enlarged cross-sectional view of a main part of the dowel when the escape groove of the caulking dowel according to the present invention is formed with a curved surface.

FIG. 6 is a cross-sectional view of a conventional caulking dowel, in which (A) shows a state before caulking and (B) shows a state after caulking.

[Explanation of symbols]

 1,11 Dowel 2,12 Arm 3,13 Shutter blade 5 Slit forming blade 6,7,8,9 Cover blade

Claims (2)

[Scope of utility model registration request] 1. A caulking hole for a shutter blade of the second shaft portion, the first shaft portion, a second shaft portion having a smaller diameter than the first shaft portion, and a step portion for receiving the shutter blade. A dowel provided with a groove for escaping at a portion facing to the boss, and by crushing the tip end portion of the second shaft portion, the shutter blade is swaged to the dowel. 2. The crimping dowel, wherein the groove is formed along the step portion with a rectangular cross-section slightly thicker than the thickness of the shutter blade. 2. The crimping dowel according to claim 1, wherein the shutter blade is a cover blade other than the slit forming blade in the blade group of the focal plane shutter.