JP5164466B2 - Camera aperture device - Google Patents

Description

  The present invention relates to a diaphragm device for a camera in which a plurality of diaphragm blades are simultaneously reciprocated in the same direction by a diaphragm ring to change the size of a diaphragm aperture formed in cooperation.

2. Description of the Related Art A camera diaphragm device has been known for a long time in which a plurality of diaphragm blades are simultaneously rotated in the same direction by a diaphragm ring to cooperatively change the size of a diaphragm aperture. In this type of diaphragm device, each diaphragm blade is rotatably attached to the main plate, and the pins provided on the diaphragm blades are elongated holes (hereinafter referred to as cam grooves) formed in the diaphragm ring. Normally, the diaphragm ring is placed in a recess formed on the blade chamber side surface of the main plate, and is rotated back and forth around the optical axis by a step motor. it is Ru as is often configured. An example of a camera diaphragm device configured in this manner is described in Patent Document 1 below. The present invention relates to a camera diaphragm device of this type.

JP 2002-258347 A

  In the camera diaphragm device described in Patent Document 1, three protrusions are formed toward the optical axis on the inner peripheral wall of the recess formed on the blade chamber side surface of the main plate, and the recess When the aperture ring rotates inside, the outer peripheral surface of the aperture ring comes into sliding contact with these protrusions. However, as is well known, tolerances are defined for parts processing. In such a configuration, if the base plate and the aperture ring are not processed with high accuracy, the aperture ring will be in the recess in the optical axis. The rotation of the aperture ring is not obtained stably, and even when the same aperture diameter is controlled, the same aperture aperture shape cannot be obtained. End up. If the center of the aperture opening deviates from the center of the optical axis or the shape of the aperture opening becomes distorted as a whole, there is little effect when the aperture diameter is relatively large, but a good image when it is small. Can no longer be obtained.

  The present invention has been made to solve such problems, and the object of the present invention is to change the size of the aperture opening by simultaneously rotating a plurality of aperture blades in the same direction. In a diaphragm device in which the diaphragm ring is disposed so as to be capable of reciprocating rotation in a recess formed in the blade chamber side surface of the main plate, the diaphragm ring does not rattle in the direction perpendicular to the optical axis in the recess and is always predetermined. It is an object of the present invention to provide a diaphragm device for a camera that can stably perform reciprocal rotation.

In order to achieve the above-described object, the diaphragm device for a camera of the present invention has a circular opening centered on the optical axis, and the surface on the blade chamber side has a circumference centered on the optical axis. and the ground plane having a recess formed an inner peripheral wall, a stop ring which is reciprocally rotated by placement by drive means substantially like a plurality of cam grooves formed in the angular interval Contact Ri before Symbol the recess , Having a pin to be individually fitted in the cam groove, and rotatably attached to the main plate, and simultaneously rotating in the same direction by the rotation of the aperture ring to change the size of the aperture opening A plurality of diaphragm blades, and a plurality of elastic parts having elasticity in a radial direction of the diaphragm ring project from the outer periphery of the diaphragm ring at a predetermined angle on the outer circumferential part of the diaphragm ring. Formed at intervals, and the aperture ring is The parts in contact with the inner peripheral wall to so that not.

In that case, the elastic portion is formed in a substantially arcuate shape centered on the optical axis so as to have a flexible and a projection formed on its front end to as in contact with the inner peripheral wall Is preferred. Further, it is advantageous in terms of cost if the diaphragm ring is made of a synthetic resin and the elastic portion is formed by integral molding of the same material.

  In the present invention, a diaphragm ring that changes the size of the diaphragm opening by simultaneously rotating a plurality of diaphragm blades in the same direction is rotatably disposed in a recess formed on the surface of the main plate on the blade chamber side. In the diaphragm device, a plurality of elastic portions having elasticity in the radial direction are formed at predetermined angular intervals on the outer peripheral portion of the diaphragm ring, and the elastic portions are always in contact with the inner peripheral wall of the recess. Therefore, the diaphragm ring has an advantage that a predetermined reciprocating rotation can be stably obtained without rattling in the direction perpendicular to the optical axis in the recess.

  Embodiments of the present invention will be described with reference to the illustrated examples. The camera aperture device of the present invention can be configured as a single aperture device or as a unitized aperture device together with the shutter device, but the embodiment is configured as a single aperture device. is there. FIG. 1 is a plan view showing a control state of the maximum aperture diameter in the aperture device of the embodiment, and FIG. 2 is a plan view showing a control state of the minimum aperture diameter in the aperture device of the embodiment. is there. FIG. 3 is a partial plan view showing a modification of the configuration of the embodiment.

  First, the configuration of this embodiment will be described mainly with reference to FIG. The camera diaphragm device of this embodiment forms a blade chamber between the main plate 1 and the auxiliary base plate 2. The auxiliary base plate 2 is attached to the base plate 1 by appropriate means, and has substantially the same outer shape as the base plate 1, but in FIG. 1, a part of the auxiliary base plate 2 is shown for easy understanding of the configuration of the blade chamber. Only shown. And the base plate 1 of a present Example is a product made from a synthetic resin, and the circular opening part 1a centering on the optical axis is formed in the center part. The auxiliary base plate 2 also has a circular opening 2a centered on the optical axis at the center thereof. However, the opening 1a of the base plate 1 has a smaller diameter, and the maximum aperture of the subject optical path (maximum The aperture diameter is regulated.

  On the surface of the base plate 1 on the blade chamber side, a recess 1b is formed so as to surround the opening 1a. The concave portion 1b has an inner peripheral wall 1c that becomes a sliding contact surface of elastic portions 3e, 3f, and 3g of an aperture ring 3 to be described later over an angle range slightly exceeding one third of the circumference around the optical axis. Is formed. In addition, three elongated holes 1d, 1e, and 1f that are arc-shaped and do not penetrate the base plate 1 are formed on the bottom surface of the recess 1b at equal angular intervals with the optical axis as the center. Further, the base plate 1 is formed with recesses 1g, 1h, 1i shallower than the recess 1b at three locations outside the edge of the inner peripheral wall 1c, and circular holes 1j, 1k, 1m are formed in them. ing.

  A diaphragm ring 3 is disposed in the recess 1b. The diaphragm ring 3 of this embodiment is made of synthetic resin and has three cam-shaped cam grooves 3a, 3b, 3c, and a tooth portion 3d and three elastic portions 3e, 3f and 3g are formed, and the elastic portions 3e, 3f and 3g are always in contact with the inner peripheral wall 1c by their elasticity. Therefore, in this embodiment, the aperture ring 3 does not move in the direction perpendicular to the optical axis in the recess 1b no matter how the camera is held.

  In the case of the present embodiment, the diaphragm ring 3 is made of synthetic resin, and the elastic portions 3e, 3f, and 3g are integrally formed of the same material. There is no problem even if it is made of metal having the same shape. In addition, the elastic portions 3e, 3f, 3g of the present embodiment are formed in an arc shape centered on the optical axis so as to have flexibility, projecting from the outer peripheral portion of the aperture ring 3, and formed at the tip thereof. However, the elastic portion of the present invention is not limited to such a shape. For example, as in the modification shown in FIG. The elastic portion 3i having flexibility is formed by forming an arc-shaped elongated hole 3h centering on the optical axis on the outer peripheral portion of the ring 3, and the protruding portion formed substantially in the middle contacts the inner peripheral wall 1c. You may make it make it. The number of elastic portions is preferably three, but may be any number as long as it is plural.

  In addition, the diaphragm device of this embodiment includes three diaphragm blades 4, 5, and 6. These diaphragm blades 4, 5, 6 are made of synthetic resin having the same shape, and have blade shafts 4a, 5a, 6a and connecting pins 4b, 5b, 6b on the same surface, and these blade shafts 4a. , 5a, 6a are rotatably fitted in the holes 1j, 1k, 1m of the base plate 1, and the connecting pins 4b, 5b, 6b are fitted in the cam grooves 3a, 3b, 3c of the aperture ring 3. I am letting. However, the diaphragm blades of the present invention may be made of metal. Further, the bottom surfaces of the recessed portions 1g, 1h, 1i of the base plate 1 are formed deeper than the bottom surface of the concave portion 1b, and the connecting pins 4b, 5b, 6b of the diaphragm blades 4, 5, 6 are connected to the blade shafts 4a, 5a, The diaphragm blades 4, 5, 6 may be disposed between the bottom surface of the recess 1 b and the diaphragm ring 3 so as to be provided on the surface opposite to 6 a. Furthermore, the diaphragm blades of the present invention are not limited to three.

  In this embodiment, the diaphragm ring 3 is reciprocally rotated by a step motor within a predetermined rotation angle range. Although the step motor is attached to the surface outside the blade chamber of the main plate 1, the configuration thereof is substantially the same as that of the known step motor described in Patent Document 1, so FIG. The detailed configuration is not shown, and the permanent magnet rotor 7 disposed outside the blade chamber of the main plate 1 and only the gear 8 disposed on the blade chamber side and attached to the output shaft 7a. It is shown. The gear 8 meshes with the tooth portion 3 d of the aperture ring 3.

  Next, the operation of this embodiment will be described. FIG. 1 shows a state in which the three aperture blades 4, 5, 6 fully open the opening 1a, that is, a control state of the maximum aperture diameter. In this state, when the rotor 7 of the step motor rotates counterclockwise, the aperture ring 3 rotates clockwise while the protruding portions at the tips of the elastic portions 3e, 3f, 3g are in contact with the inner peripheral wall 1c. Therefore, the three diaphragm blades 4, 5 and 6 are simultaneously rotated counterclockwise when the connecting pins 4b, 5b and 6b are pushed by the cam grooves 3a, 3b and 3c, and enter the opening 1a. I will do it. Therefore, the aperture diameter formed by the cooperation of the three aperture blades becomes smaller.

  When the aperture device of this embodiment is employed in a still camera, the rotor 7 stops when a predetermined aperture diameter is obtained, and shooting is performed, and the aperture device is employed in a movie camera. In such a case, the rotator 7 is rotated clockwise or counterclockwise in response to the change in the subject light so that shooting is always performed under appropriate exposure conditions. Although the aperture diameter is changed, FIG. 2 shows a state in which the minimum aperture diameter is formed as described above.

  By the way, when the aperture ring 3 is arranged so as to be able to rattle in the direction perpendicular to the optical axis in the recess 1b, the rotation of the aperture ring 3 as described above cannot be stably obtained. It will end up. Further, if the diaphragm ring 3 is moved in a direction orthogonal to the optical axis due to its own weight, the center of the diaphragm aperture is not only shifted from the center of the optical axis, but the shape of the diaphragm opening is close to an intended circle. Even if the aperture is controlled to have the same aperture, the apertures of different shapes may be obtained around different positions. Therefore, a suitable image may not be obtained particularly in the case of a control state with a small aperture. However, in the case of the present embodiment, the diaphragm ring 3 rotates with the protrusions at the tips of the elastic portions 3e, 3f, 3g being in contact with the inner peripheral wall 1c of the ground plate 1, so that the optical axis and A stable rotation can be obtained without shaking in the orthogonal direction, and a diaphragm aperture having the same shape can always be obtained at the same rotational position.

  In this way, when shooting is completed, the rotor 7 is rotated clockwise, and the aperture ring 3 and the aperture blades 4, 5, 6 are returned to the state shown in FIG. In addition, the three diaphragm blades 4, 5, 6 of the present embodiment are such that the tip of the diaphragm blade 4 is on the auxiliary base plate side from the diaphragm blade 5, and the tip of the diaphragm blade 5 is on the auxiliary base plate side from the diaphragm blade 6, The diaphragm blades 6 are overlapped so that the front ends of the diaphragm blades 6 are on the auxiliary base plate side of the diaphragm blades 4. However, the three diaphragm blades 4, 5, 6 may be simply stacked in order from the base plate 1 side. Absent. Further, the present embodiment has been described in the case where the state shown in FIG. 1 is set when shooting is not performed. However, the state shown in FIG. Needless to say.

It is the top view of the Example which showed the control state of the largest aperture diameter. It is the top view of the Example which showed the control state of the minimum aperture diameter. It is the fragmentary top view which showed the modification of the one part structure of an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ground plate 1a, 2a Opening part 1b Recessed part 1c Inner peripheral wall 1d, 1e, 1f, 3h Long hole 1g, 1h, 1i Indented part 1j, 1k, 1m hole 2 Auxiliary ground plane 3 Diaphragm ring 3a, 3b, 3c Cam groove 3d Tooth part 3e, 3f, 3g, 3i Elastic part 4, 5, 6 Diaphragm blade 4a, 5a, 6a Blade shaft 4b, 5b, 6b Connecting pin 7 Rotor 7a Output shaft 8 Gear

Claims (3)

The base plate has a circular opening centered on the optical axis, and has a concave portion with an inner peripheral wall formed on the circumference centered on the optical axis on the blade chamber side surface, and substantially equiangular intervals a diaphragm ring which is reciprocally rotated by placement by drive means a plurality of cam grooves formed on the contact Ri before Symbol the recess has to, the base plate have a pin fitted individually into the cam groove A plurality of aperture blades that are simultaneously rotated in the same direction by the rotation of the aperture ring and cooperate to change the size of the aperture opening, and the outer periphery of the aperture ring. A plurality of elastic portions having elasticity in the radial direction of the diaphragm ring are formed at predetermined angular intervals so as to protrude from the outer periphery of the diaphragm ring. camera characterized that you have contacted the peripheral wall Ri apparatus. The elastic portion, claims characterized in that it substantially arcuate is formed on contacting a projection formed on the tip to the inner peripheral wall centered on the optical axis so as to have a flexible Item 2. The aperture device for a camera according to Item 1.   3. The aperture device for a camera according to claim 1, wherein the aperture ring is made of a synthetic resin, and the elastic portion is formed by integral molding using the same material.

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