JP2009162924A - Diaphragm device for camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a diaphragm device for a camera constituted to reduce the amount of displacement from a reference surface that forms a diaphragm aperture even if diaphragm blades are bent when rotating a plurality of diaphragm blades simultaneously in the same direction to reduce the diaphragm aperture. <P>SOLUTION: The six diaphragm blades 14 are formed to fit blade shafts 14a into blade mounting holes 11c of a base plate 11 and to insert connecting pins 14b into cam grooves 13a of a diaphragm driving ring 13. Each diaphragm blade 14 is formed flat from a base end provided with the blade shaft 14a to a center part, but a tip part is formed to gently curve on the base plate 11 side toward the tip. Consequently, when the diaphragm aperture is reduced, the respective tip parts of the diaphragm blades 14 exist, on the whole, on the base plate 11 side first rather than the reference surface that forms the diaphragm aperture, but bend onto the opposite side over the reference surface toward the control state of a minimum diaphragm aperture. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  2. Description of the Related Art For a long time, a diaphragm device for a camera has been known in which a plurality of diaphragm blades are simultaneously rotated in the same direction by a diaphragm drive ring to change the size of a diaphragm aperture in cooperation. Each diaphragm blade of this type of diaphragm device is rotatably attached to the ground plate in a blade chamber formed between the ground plate and a cover plate (sometimes referred to as an auxiliary ground plate). Usually, the connecting pin is fitted in a cam groove formed in the aperture drive ring. The diaphragm drive ring is usually disposed in a concave portion formed in an annular shape around the optical axis on the surface of the main plate on the blade chamber side, and the cam groove reciprocates the diaphragm blades by reciprocating rotation. It is configured to rotate. The reciprocating rotation may be performed manually or electrically. Recently, however, there are overwhelmingly many configurations configured to be performed by a step motor. The overlapping arrangement relationship between the diaphragm blades and the diaphragm drive ring is that the diaphragm blades may be disposed between the diaphragm drive ring and the main plate as described in Patent Document 1 below. As described in Japanese Patent Application Laid-Open No. H10-228707, the diaphragm drive ring and the cover plate may be disposed.

  By the way, in the case of this type of diaphragm device, each diaphragm blade has an elongated shape as a whole, and can rotate with respect to the main plate at a position near one end (hereinafter referred to as a base end). It is attached. When the aperture opening is made smaller from the position where the exposure aperture is fully opened (maximum aperture opening control position), it is rotated to enter the exposure aperture, and the other end side portion (hereinafter referred to as the tip portion). Is closer to the center of the optical axis. However, as each diaphragm blade is advanced into the exposure aperture, the tip of the aperture blade is in a state where it only supports the tip of the adjacent aperture blade. The posture becomes unstable as it enters the lens, deviates from the reference operating surface (aperture aperture forming surface), and tends to tilt in a direction parallel to the optical axis. For this reason, it becomes impossible to appropriately change the aperture opening on the same plane, and the tip portions are separated from each other. Such a phenomenon becomes more remarkable as the aperture device having a larger diameter of the exposure aperture (maximum aperture aperture).

  Therefore, a method of assembling the aperture blade, which is commonly called a braiding method, is known. In this assembly method, all the diaphragm blades are located between two adjacent diaphragm blades, and their tips can be seen from either the ground plate side or the cover plate side, but not from the other. It is to be assembled in a proper state. By adopting this method, the tip ends become intertwined and support each other, so the large inclination of the diaphragm blades as described above is eliminated compared to the case where multiple diaphragm blades are simply stacked together. Is done. However, when this method is adopted, when the aperture is made smaller, the tips of the apertures are forced to bend each other, and the reference plane that forms the aperture is perpendicular to the reference plane. It will come to rise in the direction to do. Therefore, in the case of a diaphragm device adopting this method, if the aperture of the diaphragm is made smaller, the squeezing between the diaphragm blades becomes larger, and eventually the diaphragm blades can no longer be rotated. A diaphragm aperture cannot be formed. The aperture devices described in Patent Documents 1 and 2 are aperture devices adopting such a method, but the present invention relates to this type of camera aperture device.

JP 2005-284102 A JP 2003-57715 A

  As is well known, the camera diaphragm device is disposed in the vicinity of the photographing lens in the camera. For this reason, when the aperture device adopts the above-described weaving method, if the photographing lenses are arranged very close to both sides of the aperture device, the aperture of the aperture blade is raised by reducing the aperture opening. In this case, regardless of whether the rising direction is the base plate side or the cover plate side, the photographing lens on either side is damaged by the leading edge of the aperture blade. For this reason, even if the aperture is made smaller, it is required to minimize the amount of swell at the tip of the aperture blade from the reference plane that forms the aperture. Also, from the standpoint of manufacturing the diaphragm device, the amount of displacement due to the deflection of the diaphragm blades is reduced on either side from the reference plane that forms the diaphragm aperture, and the photographic lenses are close to both sides of the diaphragm device. For a camera that is arranged in close proximity to the camera, and for a camera in which a photographic lens is arranged close to the base plate side of the aperture device only, it is also located on the cover plate side of the aperture device. It is desirable to obtain an aperture device that can be adopted even for a camera in which only the photographing lenses are arranged close to each other.

  The present invention has been made to solve such problems, and the object of the present invention is to provide a plurality of diaphragm drive rings that are reciprocally rotated about the optical axis in a so-called knitting manner. In a diaphragm device in which the diaphragm blades are simultaneously rotated in the same direction to change the size of the diaphragm aperture, when the leading edge of each diaphragm blade is displaced by being deflected by controlling the diaphragm aperture, It is an object of the present invention to provide a camera diaphragm device in which a tip is displaced within a range extending on both sides of a reference surface forming a diaphragm aperture.

  In order to achieve the above object, the diaphragm device for a camera according to the present invention includes a ground plate and a cover plate each having a circular opening centered on the optical axis and constituting a blade chamber between the two. And a diaphragm drive ring that has a plurality of cam grooves formed at substantially equal angular intervals around the optical axis, is disposed in the blade chamber, and is reciprocally rotated around the optical axis by drive means. Each of which has a connecting pin inserted into the cam groove and is rotatably attached to the blade chamber side surface of the main plate at substantially equiangular intervals around the optical axis. A plurality of diaphragm blades forming an opening, and each of the plurality of diaphragm blades is between two adjacent diaphragm blades between the base plate and the diaphragm drive ring. So that the tip is heading to the forefront Therefore, it is formed so as to be gently curved toward the base plate side, and as the aperture opening becomes smaller, it is pushed by the aperture blades adjacent to the base plate side and bent toward the cover plate side. . In that case, each of the plurality of diaphragm blades is formed such that the tip thereof is gently curved toward the cover plate toward the forefront, and as the aperture opening becomes smaller, You may make it be pressed by the aperture blade adjacent to the said cover base plate side, and may be bent to the said base plate side.

  In the camera diaphragm device according to the present invention, each of the plurality of diaphragm blades may be between two adjacent diaphragm blades between the cover plate and the diaphragm drive ring. And the tip of the diaphragm is formed so as to be gently curved toward the ground plate as it goes to the forefront, and as the diaphragm aperture becomes smaller, the diaphragm adjacent to the ground plate side. The blade may be pushed and bent toward the cover plate. In that case, each of the plurality of diaphragm blades is formed such that their tip ends are gently curved toward the cover plate toward the forefront, and as the aperture opening becomes smaller. Further, it may be pushed by the diaphragm blades adjacent to the cover plate side and bent toward the base plate side.

  In the present invention, the diaphragm drive ring that reciprocally rotates around the optical axis is configured to change the size of the diaphragm aperture by simultaneously rotating a plurality of diaphragm blades assembled in a so-called braiding method in the same direction. In the camera diaphragm device, the plurality of diaphragm blades are formed in advance so that their front end portions are gently curved toward the base plate side or the cover plate side as they approach the leading edge. As the aperture is made smaller, the leading edge of the aperture is bent until it curves to the opposite side, so the most advanced displacement of each aperture blade is distributed from the reference plane that forms the aperture to both sides. Will be. For this reason, the amount of displacement from the reference surface is smaller than in the prior art, and there is an effect that the photographing lens is not damaged even if the photographing lens is arranged close to either side of the diaphragm device.

  Embodiments of the present invention will be described with reference to three 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 each embodiment is configured as a single aperture device. It is. 1 to 5 are for explaining the first embodiment, FIGS. 6 and 7 are for explaining the second embodiment, and FIGS. 8 and 9 are for explaining the third embodiment. It is for explaining.

  First, the first embodiment will be described with reference to FIGS. 1 to 5. FIG. 1 is a plan view showing a control state of the maximum aperture opening, and FIG. 2 is a state in the middle of narrowing from the maximum aperture opening. FIG. 3 is a plan view showing a control state of the minimum aperture stop. FIG. 4 is a single-part view showing the diaphragm blade of the first embodiment in cross section, and FIG. 5 is a cross-sectional view of the main part of FIG. First, the configuration of this embodiment will be described. The camera diaphragm device of this embodiment forms a blade chamber between the main plate 1 and the cover plate 2. The cover 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 cover plate 2 is shown for easy understanding of the configuration of the blade chamber. Only is shown and is omitted in FIGS. The base plate 1 of the present embodiment is made of synthetic resin, and has a circular opening 1a centered on the optical axis at the center. Further, the cover plate 2 is also made of synthetic resin, and an opening 2a having the same diameter as the opening 1a is formed in the center of the cover plate 2 with the optical axis as the center. Therefore, in the case of the present embodiment, the openings 1a and 2a regulate the exposure opening (maximum aperture diameter).

  A concave portion 1b is formed on the surface of the base plate 1 on the blade chamber side so as to surround the opening 1a, and the bottom surface of the concave portion 1b, that is, the surface of the base plate on the blade chamber side is approximately the center of the optical axis. Seven blade mounting holes 1c are formed at the angular interval positions, but only one of them is labeled in FIGS. In the recess 1b, an arc-shaped ridge 1d centered on the optical axis is formed on the bottom surface of a region formed to expand downward in FIG. Furthermore, in the recess 1b, a total of eight guide portions 1e having similar shapes are formed on the outer peripheral edge, but in FIGS. 1 to 3, only one of them is provided with a reference numeral. . In the base plate 1, stopper portions 1f and 1g are formed at positions slightly apart from both ends of the above-described protrusion 1d.

  Seven diaphragm blades 3 are arranged in the concave portion 1b. Since all of them have the same shape, in FIGS. It is attached. The diaphragm blades 3 have a blade shaft 3a on the base plate 1 side and a connecting pin 3b on the cover plate 2 side, and the blade shaft 3a is rotatably fitted in the blade mounting hole 1c. It is combined. In this embodiment, seven diaphragm blades 3 are assembled by a so-called knitting method. That is, as can be seen from FIG. 2 and FIG. 3, all the diaphragm blades 3 are located between two adjacent diaphragm blades 3, and in the case of this embodiment, the tip portion is adjacent. It overlaps with the diaphragm blade 3 on the base plate 1 side that is in contact with the cover plate 2 side. Therefore, in FIG. 2 and FIG. 3, those leading edges can be seen, but when viewed from the back side of the drawing (outside of the base plate 1), none of those leading edges can be seen. ing.

  By the way, the diaphragm blade 3 of the present embodiment has a shape clearly different from that of a normal diaphragm blade. The diaphragm blades have been consistently manufactured in a flat shape from the old days even though the planar shapes may vary. However, all of the seven diaphragm blades 3 of the present embodiment are not flat, but are partially curved. FIG. 4 shows one of the diaphragm blades 3 manufactured as described above. As can be seen from this drawing, the diaphragm blade 3 of the present embodiment has a base portion and a central portion. Although it is formed flat as in the prior art, the tip is manufactured so as to have a gently curved shape toward the forefront. And in the case of a present Example, all the seven aperture blades 3 are assembled | attached with the attitude | position which the front-end | tip part curves to the ground plane 1 side. Therefore, in FIGS. 1 to 3, a boundary line between the flat surface and the curved surface of each diaphragm blade 3 is indicated by reference numeral 3 c.

  In the recess 1b, an aperture drive ring 4 is disposed on the cover plate 2 side of the aperture blade 3, and the outer peripheral surface is in contact with the eight guide portions 1e, with the optical axis as the center. It can be reciprocated. The diaphragm drive ring 4 has seven cam grooves 4a each having a long hole shape formed at substantially equal angular intervals around the optical axis, and the connecting pins 3b are individually inserted. Further, the diaphragm drive ring 4 has a tooth portion 4b and an overhang portion 4c in a part of the outer peripheral portion, and the overhang portion 4c is in sliding contact with the above-described protrusion 1d. The diaphragm drive ring 4 is prevented from coming out of the recess 1b by a portion (not shown) provided on the cover plate 2.

  In the present embodiment, such a diaphragm drive ring 4 is reciprocally rotated within a predetermined rotation angle range by a step motor. And although the step motor is attached to the main plate 1 outside the blade chamber, since the configuration is not directly related to the present invention, in FIG. 1 to FIG. Only the output shaft 5a penetrated to the chamber side is shown. A gear 6 is attached to the output shaft 5 a of the rotor 5, and a parent-gear gear (two-stage gear) 7 is rotatably attached to the shaft 1 h erected on the main plate 1. In the master-slave gear 7, the master gear meshes with the gear 6, and the slave gear meshes with the tooth portion 4 b of the aperture drive ring 4. Although the diaphragm drive ring 4 of this embodiment is configured to be reciprocated by a step motor, the diaphragm drive ring of the present invention may be manually reciprocated.

  Next, the operation of this embodiment will be described. FIG. 1 shows a state in which the seven aperture blades 3 fully open the opening 1a, that is, a control state of the maximum aperture opening. If the subject light is darker than a predetermined brightness, the state remains as it is. Shooting is performed. However, when the subject light is brighter than the predetermined brightness, the rotor 5 of the step motor is rotated clockwise. As a result, the diaphragm drive ring 4 is rotated clockwise via the gear 6 and the parent-child gear 7, so that the seven diaphragm blades 3 are simultaneously pressed by their connecting pins 3b being pushed by the cam grooves 4a. It is rotated counterclockwise and enters the opening 1a, and the aperture of the diaphragm is reduced by their cooperation.

  When the aperture device of this embodiment is employed in a still camera, the rotor 5 stops when a predetermined aperture opening is obtained, shooting is performed, and the aperture device is employed in a movie camera. In the case where the subject light is changed, the rotator 5 is rotated clockwise or counterclockwise in accordance with the change of the subject light so that shooting is always performed under appropriate exposure conditions. Therefore, the aperture opening is changed. FIG. 2 shows a state in which the seven diaphragm blades 3 are in the middle of the maximum diaphragm opening and the minimum diaphragm opening and are substantially approaching the minimum diaphragm opening control state. There are almost no phenomena specific to the system.

  Therefore, in this state, as described above, the diaphragm blades 3 are formed in advance so that their tip portions are gently curved toward the base plate 1 side. The force which pushes the diaphragm blade 3 which adjoins by the side to the baseplate 1 side acts, and conversely, the force which pushes the diaphragm blade 3 which adjoins by the cover plate 2 side acts. . However, each diaphragm blade 3 is made flat except for the tip, and is basically assembled so that the flat portion is substantially the same as the reference plane that forms the aperture opening. As a whole, these tip portions are in a state slightly existing on the ground plane 1 side with respect to the reference plane. However, if the amount of displacement of the tip portion from the reference plane is such a level, the diaphragm blade 3 may come into contact with the lens surface even if the photographic lens is disposed in the proximity position on the ground plane 1 side. Absent.

  When the diaphragm drive ring 4 is further rotated clockwise from the state of FIG. 2, a phenomenon peculiar to the weaving method appears, and each diaphragm blade 3 is located on the cover plate 2 side (front side in FIG. 2). They are bent and their tips rise. However, in the case of the present embodiment, the tip is not bent from the reference surface that forms the aperture opening as in the conventional case, but is bent from the base plate 1 side to the cover plate 2 side from the reference surface. Therefore, the amount of displacement from the reference surface to the cover plate 2 is smaller than in the conventional case. Then, the state in which the rotation of the diaphragm drive ring 4 is stopped by the contact of the overhanging portion 4c with the stopper portion 1g, that is, the control state of the minimum diaphragm opening is shown in FIGS. It is. As shown in FIG. 5, at this time, the tip of the diaphragm blade 3 is curved to the opposite side, but the most advanced displacement from the reference surface is smaller than the conventional one, Even if the photographing lens is arranged in the proximity position on the cover plate 2 side, the diaphragm blade 3 does not come into contact with the lens surface. In the present embodiment, the diaphragm drive ring 4 exists between the diaphragm blades 3 and the cover plate 2. Therefore, the amount of displacement up to the reference surface is not the same as the amount of displacement from the reference surface. You may make it the displacement amount to the cover board 2 side become large.

  When photographing is completed in such a state, the rotor 5 is rotated counterclockwise, and the aperture driving ring 4 is rotated counterclockwise. Accordingly, the seven diaphragm blades 3 are rotated in the clockwise direction when their connecting pins 3b are pushed by the cam grooves 4a of the diaphragm drive ring 4. These rotations are stopped when the overhanging portion 4c of the aperture driving ring 4 abuts against the stopper portion 1f. This state is the state shown in FIG. In the present embodiment, it has been described that FIG. 1 is in a state before the start of photographing. However, depending on the specifications of the camera, for example, the state shown in FIG. 2 or FIG. It may be in the state of.

  In the case of the present embodiment, the seven diaphragm blades 3 are assembled such that the tip portions are always in contact with the diaphragm blades 3 adjacent to the base plate 1 side. The shape is formed so as to be gently curved toward the main plate 1 as it goes to the forefront. However, in the present invention, the seven diaphragm blades 3 are arranged adjacent to the cover plate 2 side. (In this case, the leading edge of each diaphragm blade 3 is visible only from the main plate 1 side), and the shape of the tip is You may make it the structure currently formed so that it may curve to the cover board 2 side gradually toward the forefront.

  Next, Example 2 will be described with reference to FIGS. 6 and 7. FIG. 6 is a plan view showing a control state of the maximum aperture opening, and FIG. 7 shows a control state of the minimum aperture opening. It is a top view. First, the configuration of this embodiment will be described. The cover plate 12 constituting the blade chamber with the base plate 11 has substantially the same outer shape as the base plate 11, and is attached to the base plate 11 by appropriate means. Only the portion is shown, and is not shown in FIG. The base plate 11 and the cover plate 12 of the present embodiment are made of synthetic resin, and have openings 11a and 12a having the same diameter centered on the optical axis at the center thereof. Therefore, also in the case of the present embodiment, the openings 11a and 12a regulate the exposure opening (maximum aperture diameter).

  On the surface of the base plate 11 on the blade chamber side, a recess 11b is formed so as to surround the opening 11a. The annular surface surrounding the recess 11b is formed with six blade mounting holes 11c at substantially equal angular positions centered on the optical axis. is there. An aperture driving ring 13 is disposed inside the recess 11b so as to be capable of reciprocating around the optical axis. The diaphragm drive ring 13 has six cam grooves 13a formed at substantially equal angular intervals around the optical axis, and a tooth portion 13b and three notches 13c are formed on the outer peripheral portion. These cam grooves 13a and notches 13c are provided with only one reference numeral.

  And this diaphragm drive ring 13 matches the position of the three notches 13c with the position of the three hook parts 11d (reference numerals are attached to only one) formed on the base plate 11, It is made to occupy the position of FIG. 6 by being dropped into the recess 11b and then rotating clockwise. As described above, in the case of the present embodiment, the diaphragm drive ring 13 is prevented from coming out of the recess 11b by the three hook portions 11d. This is because a diaphragm blade 14 to be described later is disposed between the ring 13 and the cover plate 12 and cannot be prevented by the cover plate 12 as in the first embodiment.

  In the case of this embodiment, six diaphragm blades 14 are arranged between the diaphragm drive ring 13 and the cover plate 12, but only one of them is provided with a reference numeral. Unlike the case of the first embodiment, the diaphragm blade 14 of the present embodiment has both the blade shaft 14a and the connecting pin 14b provided on the surface on the side of the base plate 11, and the blade shaft 14a is connected to the above-described blade shaft 14a. The connecting pin 14b is inserted into the cam groove 13a by being rotatably fitted in the blade mounting hole 11c. And the code | symbol of those blade shafts 14a and the connection pin 14b is also attached | subjected only with respect to the one aperture blade 14 to which the code | symbol was attached | subjected. Also in the case of the present embodiment, the six diaphragm blades 14 are assembled in a braided manner. That is, as can be seen from FIG. 6 and FIG. 7, all the diaphragm blades 14 are between two adjacent diaphragm blades 14, and their tips are located on the adjacent base plate 11 side. The diaphragm blades 14 are stacked so as to be in contact with the cover plate 12 side. Therefore, in the state of FIG. 7, all of the leading edges can be visually observed, but when viewed from the back side of FIG. 7 (outside of the base plate 11), the leading edges are not visible at all. It has become.

  As described above, the diaphragm blade 14 of the present embodiment is different from the diaphragm blade 3 of the first embodiment in a planar shape, and also differs in that the blade shaft 14a and the connecting pin 14b are provided on the same surface side. . However, in the case of the six diaphragm blades 14 of the present embodiment, the base end portion of the six diaphragm blades 14 of the first embodiment is not shown in the single product diagram as shown in FIG. From the center to the center, it is formed flat as in the prior art, but the tip is manufactured in a shape that gently curves toward the ground plane 11 as it goes to the forefront. Therefore, in FIG.6 and FIG.7, the boundary line of the flat surface and a curved surface is shown with the code | symbol 14c.

  Next, also in the case of the present embodiment, the aperture drive ring 13 is reciprocally rotated by a step motor. The step motor does not clearly show all of the specific configuration, but is substantially the same as the configuration of the well-known step motor described in Patent Document 1, and the rotor 15 made of a permanent magnet is The synthetic resin gear 16 is integrated, and is rotatably attached to a shaft 11e standing on the base plate 11. Further, a parent gear (two-stage gear) 17 is rotatably attached to a shaft 11 f erected on the main plate 11, the parent gear meshes with the gear 16, and the slave gear is a tooth of the aperture drive ring 13. It meshes with the portion 13b.

  Next, the operation of this embodiment will be described. In the case of the present embodiment, unlike the diaphragm blade 3 of the first embodiment, six diaphragm blades 14 are arranged between the cover plate 12 and the diaphragm drive ring 13. The interlocking relationship with the drive ring 13 is substantially the same as in the first embodiment. Further, the other configurations are differences that cannot be said to be different from the viewpoint of the present invention. Therefore, since the operation of the present embodiment is performed in substantially the same manner as in the first embodiment, overlapping points will be described briefly. FIG. 6 shows a state in which the six aperture blades 14 fully open the opening 11a, that is, a control state of the maximum aperture opening. At the time of shooting, when the subject light is brighter than the predetermined brightness, the rotor 15 of the step motor is rotated counterclockwise, and the diaphragm drive ring 13 is moved counterclockwise via the gear 16 and the parent gear 17. Rotate clockwise. For this reason, the six diaphragm blades 14 are simultaneously rotated clockwise to enter the opening portion 11a, thereby reducing the aperture opening.

  However, at the stage where the aperture opening is relatively large, a phenomenon peculiar to the weaving method hardly appears. Therefore, in such a stage, each leading edge pushes the diaphragm blades 14 adjacent on the ground plane 11 side to the ground plane 11 side, and conversely, the leading edge by the diaphragm blades 14 adjacent on the ground plane 11 side. Is pushed to the cover plate 12 side. However, since each diaphragm blade 14 is made flat except for the tip part, the tip part as a whole is in a state slightly existing on the base plate 11 side from the reference plane forming the diaphragm opening. Yes. However, since the diaphragm drive ring 13 is disposed on the base plate 11 side of the diaphragm blade 14, the diaphragm blade 14 may come into contact with the lens surface even if the photographing lens is disposed in the proximity position on the ground plate 11 side. There is nothing wrong.

  From this state, when the diaphragm drive ring 13 is further rotated counterclockwise and approaches the control state of the minimum diaphragm opening, a phenomenon peculiar to the weaving method appears, and the tip of each diaphragm blade 14 is covered with the cover. They are bent to the plate 12 side, and their leading ends rise above the reference plane and rise to the cover plate 12 side (front side in FIG. 6). However, in the case of the present embodiment, since it is bent from the base plate 11 side with respect to the reference plane, the displacement amount from the reference plane when the minimum aperture opening is controlled is the case of the conventional configuration. Less than. FIG. 7 shows such a control state of the minimum aperture, but as can be seen from FIG. 7, the notch of the aperture drive ring 13 is maintained even when the minimum aperture is controlled. Since 13c does not reach the position of the hook portion 11d, the diaphragm drive ring 13 does not move from the concave portion 11b to the diaphragm blade 14 side during operation.

  Thus, in the case of the present embodiment, the amount of displacement of the leading edge of the diaphragm blade 14 from the reference plane that forms the diaphragm opening toward the cover plate 12 in the minimum diaphragm opening control state is larger than the conventional one. Less. Therefore, even if the photographic lens is disposed in the proximity position on the cover plate 12 side, the diaphragm blade 14 does not come into contact with the lens surface. In this embodiment, only the diaphragm device is unitized, but such a diaphragm device may be configured as one unit together with the shutter device. In that case, an intermediate plate is generally arranged between the cover plate 12 and the diaphragm blade 14 and the blade plate chamber of the shutter blade is formed between the intermediate plate and the cover plate 12. In the case of the configuration, as in the prior art, if the most advanced displacement amount of the diaphragm blade 14 is large, it would be difficult to adopt because it interferes with the shutter blade in operation. If it is a structure, it will also be employable for such a unit.

  When the aperture opening is controlled in this way and photographing is completed, the rotor 15 is rotated clockwise, and the aperture drive ring 13 is rotated clockwise. Thereby, the six diaphragm blades 14 are rotated counterclockwise by pushing their connecting pins 14b into the cam grooves 13a of the diaphragm drive ring 13. Then, the rotation is stopped by stopping the rotation of the rotor 15 after the opening 11a is fully opened. This state is the state shown in FIG.

  Next, Embodiment 3 will be described with reference to FIGS. 8 and 9. FIG. 8 is a plan view showing a control state of the maximum aperture opening, and FIG. 9 shows a control state of the minimum aperture opening. It is a top view. Therefore, the configuration of the present embodiment will be described, but the shape of each member constituting the present embodiment is exactly the same as that of the second embodiment. For this reason, the members and parts shown in FIGS. 8 and 9 are given the same reference numerals as those in FIGS. 6 and 7, and the description thereof is omitted. The configuration of the present embodiment is different from the configuration of the second embodiment described above in that the way of assembling the six aperture blades 14 to the main plate 11 is different. That is, also in the case of the present embodiment, the six diaphragm blades 14 are assembled in a knitting manner, but the knitting directions are reversed.

  As shown in FIGS. 8 and 9, also in the case of the present embodiment, the diaphragm blade 14 can rotate its blade shaft 14a to the blade mounting hole 11c of the base plate 11 as in the case of the second embodiment. The connecting pin 14b is inserted into the cam groove 13a of the aperture drive ring 13. Also in this embodiment, since all the diaphragm blades 14 are between two adjacent diaphragm blades 14 because they are knitted, in this embodiment, in FIG. In the state, the front end portions thereof are overlapped so as to be in contact only with the diaphragm blades 14 on the adjacent cover plate 12 side. Therefore, even if it becomes the state of FIG. 9, those cutting edges cannot be visually observed at all, and when viewed from the back side of FIG. ing.

  Next, the operation of the present embodiment will be described, but the description overlapping with the case of the second embodiment will be made as simple as possible. When photographing, if the subject light is brighter than the predetermined brightness, the rotor 15 is rotated counterclockwise in the state shown in FIG. 8, and the aperture drive ring 13 is rotated counterclockwise. For this reason, the six diaphragm blades 14 are simultaneously rotated clockwise to enter the opening portion 11a, thereby reducing the aperture opening. At the stage where the aperture opening is relatively large, each leading edge pushes the aperture blades 14 adjacent on the cover plate 12 side toward the cover plate 12 side, and conversely on the cover plate 12 side. The leading edge is pushed toward the main plate 11 by the diaphragm blades 14. However, since each diaphragm blade 14 is made flat except for the tip part, the tip part as a whole is slightly on the cover plate 12 side with respect to the reference surface forming the diaphragm opening. ing. However, even if the photographing lens is disposed in the proximity position on the cover plate 12 side, the aperture blade 14 does not come into contact with the lens surface.

  From this state, when the diaphragm drive ring 13 is further rotated counterclockwise to approach the control state of the minimum diaphragm opening, a phenomenon peculiar to the weaving method appears, and the tip of each diaphragm blade 14 is on the base plate 11 side. (The back surface side in FIG. 8) is bent, and the tips thereof rise to the base plate 11 side beyond the reference surface forming the aperture opening. However, in the case of the present embodiment, since it is bent from the cover plate 12 side with respect to the reference surface, the amount of displacement from the reference surface when the minimum aperture opening is controlled is the same as the conventional configuration. Less than the case. Therefore, even if the photographic lens is arranged in the proximity position on the side of the base plate 11, the diaphragm blade 14 does not come into contact with the lens surface. FIG. 9 shows the control state of such a minimum aperture. Thereafter, when shooting is completed, the rotor 15 is rotated clockwise, and the diaphragm drive ring 13 is rotated clockwise. Therefore, the six diaphragm blades 14 are rotated counterclockwise, and after the opening 11a is fully opened, the rotation of the rotor 15 stops. This state is the state shown in FIG.

It is the top view of Example 1 which showed the control state of the largest aperture opening. It is the top view of Example 1 which showed the state in the middle of narrowing down. It is the top view of Example 1 which showed the control state of the minimum aperture stop. It is the single article figure which showed the aperture blade in Example 1 in the cross section. It is principal part sectional drawing of FIG. It is the top view of Example 2 which showed the control state of the largest aperture opening. It is the top view of Example 2 which showed the control state of the minimum aperture stop. It is the top view of Example 3 which showed the control state of the largest aperture opening. It is the top view of Example 3 which showed the control state of the minimum aperture stop.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 Ground plate 1a, 2a, 11a, 12a Opening part 1b, 11b Recessed part 1c, 11c Blade attachment hole 1d Projection 1e Guide part 1f, 1g Stopper part 1h, 11e, 11f Shaft 2,12 Cover board 3,14 Diaphragm blade 3a, 14a Blade shaft 3b, 14b Connecting pin 3c, 14c Boundary line 4, 13 Diaphragm drive ring 4a, 13a Cam groove 4b, 13b Tooth part 4c Overhang part 5, 15 Rotor 5a Output shaft 6, 16 Gears 7, 17 Parent-child gear 11d Hook part 13c Notch

Claims (4)

  A ground plate and a cover plate each having a circular opening centered on the optical axis and constituting a blade chamber between the two, and a plurality of holes formed at substantially equal angular intervals around the optical axis A diaphragm drive ring which has a cam groove and is arranged in the blade chamber and is reciprocally rotated around the optical axis by a drive means, and each of which has a connecting pin inserted into the cam groove and has a light. A plurality of diaphragm blades that are rotatably attached to the blade chamber side surface of the main plate at substantially equiangular intervals centered on the axis, and cooperate to form a diaphragm aperture, and the plurality Each of the diaphragm blades is overlapped between the base plate and the diaphragm drive ring so as to be between the two adjacent diaphragm blades, and the leading end thereof is directed to the forefront. It is formed so as to be gently curved toward the main plate side. Has been, as the aperture stop decreases, pushed diaphragm blades adjacent to the ground plate side, a camera diaphragm device is characterized in that so as to be deflected to the cover plate side.   Each of the plurality of diaphragm blades is formed such that the tip thereof is gently curved toward the cover plate toward the foremost end, and the cover base plate becomes smaller as the aperture opening becomes smaller. 2. The diaphragm device for a camera according to claim 1, wherein the diaphragm device is pushed by a diaphragm blade adjacent to the side and is bent toward the base plate.   Each of the plurality of diaphragm blades is overlapped between the cover plate and the diaphragm drive ring so as to be between two adjacent diaphragm blades, and the leading end thereof is at the forefront. It is formed so as to be gently curved toward the base plate as it goes, and as the aperture opening becomes smaller, it is pushed by the aperture blades adjacent to the base plate side and bent toward the cover plate side. The diaphragm device for a camera according to claim 1, wherein   The plurality of diaphragm blades are all formed such that their tip portions are gently curved toward the cover plate toward the forefront, and the cover becomes smaller as the aperture opening becomes smaller. 4. The diaphragm device for a camera according to claim 3, wherein the diaphragm device is pushed by a diaphragm blade adjacent to the plate side and bent toward the base plate side.

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