JP2000089294A - Blade opening/closing device for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blade opening/closing device for a camera which is easily assembled and hardly falls off and in which so-called backlash gathering is performed through a spring. SOLUTION: A torsion coil spring 5 is inserted and fit in the supporting shaft 4b of a diaphragm blade 4, and a part 4d around the supporting shaft is inserted in the gap 5d of a coil part 5a, so that the spring is attached to the blade. When both arms 5b and 5c are made to abut on the supporting part 1a of a base member 1 and deformed, the coil part 5a is tightened and abuts on one part 4e of the blade. Since force is applied to one part 4e of the blade from the coil part 5a, energizing force is applied to the blade 4 in a clockwise direction. By changing how to attach the spring 5, the blade 4 is energized in a counterclockwise direction, so that the energizing force in an optional direction is applied to the blade 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blade opening / closing device for a camera.

[0002]

2. Description of the Related Art As is well known, a plurality of shutter blades of a camera and blades of an aperture device are generally opened and closed by swinging simultaneously. FIG. 6 is an enlarged view showing an example of a conventional swing mechanism of a diaphragm blade of a camera. As shown in the figure, an aperture blade 22 supported by a support shaft 22a is swingably attached to the vicinity of the outer peripheral portion of a circular base member 21. The diaphragm blade 22 has a mechanism in which a blade operating pin 22b serving as a cam follower is engaged with a cam groove 23a provided in a cam ring (not shown), and the diaphragm blade 22 swings and opens / closes by rotation of the cam ring. Has become.

By the way, the opening and closing of the aperture blade is performed by a cam groove 23a.
And the operation pin 22b, and a relative movement is also performed between the two. Therefore, a slight gap is required between the two, and a gap due to a machining error is required. And so on. Since this gap causes an error in the open / close position of the diaphragm blade 22, a so-called so-called biasing force is applied to the diaphragm blade in an arbitrary direction so that an arbitrary side portion is always in elastic contact. "Wobbling" is being performed. In FIG. 6, the coil portion 24a of the torsion coil spring 24 is inserted into the support shaft 22a, one arm portion 24b is bent in an L shape, and this bent portion engages with one side of the diaphragm blade, and By contacting the arm portion 24c with the spring support portion 21a provided on the base member, a clockwise urging force is applied to the diaphragm blade.

[0004]

In the above conventional example, when one arm 24c of the torsion coil spring is not in contact with the supporting portion 21a, it rotates freely, so that the state before the assembling is performed from the support shaft. It is easy to come off and is troublesome to assemble. In addition, there is a problem that the spring is easily detached by vibration because it is merely attached to the support shaft 22a.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problem, a blade opening / closing device for a camera according to the present invention includes a blade which is inserted into a gap formed in a coil portion of a torsion coil spring inserted into a support shaft of the blade. The mounting of the spring is facilitated by clamping the portion around the support shaft. By applying a force in the direction in which the coil section contracts through the arms extending outward from both ends of the coil section to generate a torsional moment, a biasing force is applied to the blade in an arbitrary direction. The direction in which the urging force acts can be changed by changing the position of the aperture blade to the torsion coil spring. Accordingly, even if the direction in which the urging force of the blade acts is made different, the types of components can be reduced by making it possible to respond.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a camera blade opening / closing device according to the present invention, a torsion coil spring is inserted into a support shaft of a camera blade such as an aperture blade, and a part of the blade is formed by a coil portion of the torsion coil spring. The torsion coil spring is characterized in that the torsion coil spring is attached so as to generate a biasing force on the blade by deforming the spring in a direction in which the spring contracts through arms extending from both ends. .

[0007]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a main part of a diaphragm device as one embodiment of the present invention. As shown, a ring-shaped cam ring 2 is rotatably mounted inside a ring-shaped base member 1. Part of the outer peripheral portion of the cam ring has a tooth portion 2a that meshes with a motor pinion (not shown) of the motor 3.
Is provided. Eight aperture blades 4 are attached to the edge of the base member 1 (only one is shown).

As shown in FIG. 2, the diaphragm blade 4 is formed by forming an outwardly extending portion at one end of a diaphragm portion 4a formed in an arc shape and providing a support shaft 4b at the tip end. The diaphragm blade 4 is attached to the edge of the base member via a support shaft 4b.
When the sheets are mounted at equal angular intervals and each of them swings clockwise, the aperture hole formed by the inner arc is reduced, and finally becomes a pinhole. When each of the aperture blades 4 swings counterclockwise, the aperture hole is configured to be large.

As shown in FIG. 1, at the edge of the cam ring 2, there are eight cam grooves 2b... It is provided at intervals. An aperture blade operating pin 4c provided on the back surface of the aperture blade 4 is slidably engaged with each cam groove 2b. When the cam ring 2 rotates, each of the diaphragm blades 4 can swing by the operation pin 4c relatively moving in the cam groove 2b about the support shaft 4b.

Next, the mounting structure of the aperture blade 4 will be described with reference to FIGS. The support shaft 4b of the diaphragm blade is inserted into the coil portion 5a of the torsion coil spring 5, and a portion around the support shaft, that is, a part 4d of the blade is inserted into a gap between the coil portions. . The tip end of the support shaft 4b is supported by a bearing 6a of a substrate 6 provided so as to face the base member 1 so that the diaphragm blade 4 can swing. The torsion coil spring 5 inserted into the support shaft 4b is
The number of turns of the material of the coil portion 5a is three, and each end is provided with arm portions 5b and 5c extending in opposite directions.
A gap 5d is provided between the windings of the coil portion 5a.

The torsion coil spring 5 is attached to the diaphragm blade 4 by inserting the coil portion 5a on the support shaft 4b before assembling the diaphragm blade 4, and then attaching the arm portion 5b to the back side of the diaphragm blade 4 on the left side of the drawing. The torsion coil spring 5 is rotated one turn clockwise about the support shaft 4b. Then, the state shown in FIG. 3 is obtained, and the portion (part of the blade) 4d around the support shaft 4b is held in the gap between the coil portions. Incorporation of the diaphragm blade 4 with the torsion coil spring 5 inserted therein engages the operating pin 4c with the cam groove 2b, and the arm portions 5b, 5c of the torsion coil spring are formed in the spring receiving portion 1a formed inside the base member 1. , 1b, and the diaphragm blades 4 are further pushed in toward the outer periphery of the base member to deform the two arms 5b, 5c of the spring so as to be inclined. Then, the bearing 6a of the substrate is inserted into the support shaft 4a. To fix the position of the spindle.

At this time, the coil portion 5a is connected to both arms 5b, 5
When c is inclined and wound up, it is compressed and its diameter becomes smaller. At this time, a portion 4e of the diaphragm blade in contact with the coil portion 5a receives a force from the coil portion 5a, and as a result, the diaphragm blade 4 receives a biasing force in the clockwise direction. For this reason, since the spring force is always applied to the diaphragm blade, the diaphragm blade is in a state without "play", that is, a so-called "backlash" state, and the opening and closing operation of the blade is made accurate.

[0013] The "backlash" is not always employed only in the direction in which the blades are closed, but may be required in the direction in which the blades are opened. In this case, first, the torsion coil spring 5 is rotated about the support shaft 4b so that the arm 5b comes to the right side in the drawing. Thereafter, the arm 5b is inserted under the portion 4d around the support shaft 4b while rotating the arm 5b clockwise, so that the arm 5b is located on the left side of the drawing. Then, the state shown in FIG. 5 is obtained. In this case, a portion 4e of the diaphragm blade in contact with the coil portion 5a is on the right side of the diaphragm blade, so that the diaphragm blade 4 is urged counterclockwise. In this way, the diaphragm blade 4 can be urged both clockwise and counterclockwise without changing the torsion coil spring 5 only by changing the mounting method.

The mechanism for opening and closing the blades of the camera described above is not intended to be limited to the one shown in the drawing, but can be applied to any other mechanism for opening and closing the blades. In this embodiment, the aperture blade is described. However, the present invention is not limited to the aperture blade, but can be widely applied to all types of camera blade opening / closing devices such as an exposure device blade.

[0015]

According to the present invention, the so-called "backlash" of the blades of the camera can be achieved with a simple structure, and the spring does not easily come off the support shaft. Further, since the assembly is easy, the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view of a main part of an aperture blade device as one embodiment.

FIG. 2 is a front view of an aperture blade.

FIG. 3 is an enlarged front view showing an attached state of an aperture blade.

FIG. 4 is a side view showing a state where an aperture blade is inserted into a gap between coil portions of the torsion coil spring.

FIG. 5 is an enlarged front view showing a state in which the diaphragm blade is inserted into another gap of the torsion coil spring.

FIG. 6 is an enlarged front view showing a state where a diaphragm blade is mounted in a conventional example.

[Explanation of symbols]

 4 diaphragm blade 4b support shaft 4d part 5 torsion coil spring 5a coil unit 5b, 5c arm unit

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Seiichi Konno 1-1-1 Akanehama, Narashino-shi, Chiba F-term in Seiko Precision Co., Ltd. (reference) 2H080 AA21 AA37

Claims (1)

[Claims] 1. A torsion coil spring is mounted on a spindle of a camera blade such as an aperture blade, and a part of the blade is inserted into a gap between coil portions of the torsion coil spring. A blade opening / closing device for a camera, wherein the spring is attached so as to generate an urging force on the blade by deforming the spring in a direction in which the spring contracts via an arm extending from both ends.