JPH0430585Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a lens aperture device.

(Prior art) This type of lens barrel diaphragm device has an aperture setting in which the aperture drive plate can be externally operated in order to open and close the aperture blades provided between the aperture drive plate and the honeycomb (support plate). A small part that is configured to be controlled in conjunction with the aperture ring, is arranged between the aperture setting ring and the aperture drive plate, and is composed of, for example, a ring-shaped cam plate, or has a cam part directly on the aperture setting ring. It was configured by installing.

(Problem to be solved by the invention) The aperture device made of such a ring-shaped cam plate is fitted into the inner periphery of the lens barrel, and the space where the aperture device is fitted is the fixed tube. Because it spans the entire circumference, it is impossible to place other parts on the fixed tube surface of the mating part, and in recent lens barrels where electronic components are placed inside the lens barrel, it is difficult to place other parts on the fixed tube surface. It is important to use it efficiently, and some disadvantages also arise.

In addition, in the case where a cam member is attached directly to the aperture setting ring, when controlling the amount of movement of the aperture setting ring by converting it into the amount of movement of the aperture blades via the cam member, the aperture setting ring is If the aperture is deformed by the force, the deformation is transmitted to the cam member and there is a possibility that the aperture diameter may be distorted.

The purpose of the present invention is to solve these drawbacks, effectively utilize the space within the lens barrel, and prevent deformation of the aperture diameter.

(Means for Solving the Problems) The present invention provides a cam plate that is linked to an externally operable aperture setting ring 13 of a lens barrel and converts the amount of movement of the aperture setting ring into the amount of movement of the aperture blades 16. 1
4 was formed into a semicircular shape, and the cam plate was arranged between a first guide member 11 that guided the outer periphery of the cam plate and a second guide member 12 that guided the inner periphery of the cam plate.

(Function) The present invention can be miniaturized because the cam plate is configured in a semicircular shape, and since the cam plate is guided by the first guide member and the second guide member, there is no adverse effect on the aperture diameter. .

(Example) Figures 1 to 3 show examples of the present invention.
2 is a cross-sectional view of the lens barrel, FIG. 2 is another cross-sectional view of the lens barrel shown in FIG. 1, and FIG. 3 is an exploded perspective view of the aperture device of the lens barrel.

In FIGS. 1 and 2, photographic lens group 1,
A bayonet mount 12 with a connecting part to the camera body is attached to the rear of the main body 11 that holds the camera body 1 with the screw 1.
It is installed at 0. Aperture setting ring 13
is provided on the outer periphery of the main body 11 so as to be rotatable by external operation, and the aperture setting ring 13 is engraved with an aperture value. Further, the cam plate 14 is connected to the main body 1
The optical axis direction and the radial direction are sandwiched between the inner periphery of the mount 1 and the mount 12, and the mount 12 is rotatably provided. This aperture setting ring 13 is connected to a cam plate 14 provided inside the main body 11.
The cam plate is driven in accordance with the amount of movement.

Inside the main body 11 are a honeycomb 17 and an aperture drive plate 15.
A diaphragm unit having diaphragm blades 16 is installed between the two. The aperture value set by the aperture setting ring 13 is transmitted to this aperture unit by a cam plate 14 and an aperture transmission plate 18, and the aperture blades 16 are controlled in accordance with the aperture value of the aperture setting ring 13. A mechanism for transmitting the aperture value set by the aperture setting ring 13 to the aperture unit will be explained with reference to FIG.

In FIG. 3, a mount 12 fixed to the main body 11 is formed with a ring-shaped protrusion 12a that protrudes in the optical axis direction on the inner diameter side, and an aperture setting ring 13 is formed with a ring-shaped protrusion 12a that protrudes in the optical axis direction on the inner diameter side. An engaging portion 13a that protrudes and forms a groove is formed, and the cam plate 14, which is formed in a semicircular shape, has a protruding engagement portion that engages with the engaging portion 13a on the outer circumferential side of the semicircular shape. A portion 14a is formed, and a cam surface 14d is formed on the inner peripheral side of the semicircular shape, and the aperture transmission plate 18 has a cylindrical lever 18a that slides on the cam surface 14d of the cam plate 14. A connecting lever 18b is provided in the optical axis direction and is provided in the axial direction and connected to the aperture driving plate 15 of the aperture unit. This aperture transmission plate 18 is also formed in a semicircular shape, and is rotatably supported by the main body 11 at a rotation center 18c at an end thereof, and a connecting lever 18b provided at the other end is supported by a spring (not shown). The biased lever 18a is brought into contact with the cam surface 14d.

The cam plate 14 formed in a semicircular shape has an inner circumferential surface 14c that is connected to the ring-shaped protrusion 12a of the mount 12.
The cam plate 14 is provided so as to slide on the circumferential surface of the mount 12, and its outer circumferential surface 14b is provided so as to slide on the inner circumferential surface 11a of the main body 11. It is rotatably held by the outer peripheral surface 12a. And cam plate 1
4 and the aperture setting ring 13 are connected by a cam plate 14.
The engaging portion 13a of the diaphragm setting ring 13 is inserted through the arcuate cutout portion 11b of the main body 11 into the engaging portion 14a of the diaphragm setting ring 13. The movement of the engaging portion 13a in the circumferential direction is restricted by the arc-shaped notch portion 11b of the main body 11, so that the aperture setting ring 13 can move within a certain range.

When the aperture value is set using the aperture setting ring 13, the cam plate 14 is
rotates, and due to the rotation of the cam plate 14, the cam surface 1
The lever 18a sliding on the cam surface 14d
The lever 18 moves along the center of rotation 18c.
Rotate around. As the lever 18 moves, the aperture drive plate 15 is rotated via the lever 18b and the notch 15a. This cam surface 14d
Accordingly, the amount of movement of the aperture setting ring 13, that is, the amount corresponding to the set aperture value is converted, and the aperture blades are controlled to reach the set aperture value.

When the diaphragm drive plate 15 is rotated, the diaphragm blades 16 move around the rotation shaft 16b fitted into the hole 17a of the honeycomb 17, and move around the groove 1 of the diaphragm drive plate 15.
The lever 16a moves along the aperture value 5b and is controlled to the set aperture value.

(Effects of the invention) As described above, according to the invention, the cam plate interlocked with the aperture setting ring is not adversely affected by the deformation of the aperture setting ring, and for this reason, the material of the aperture setting ring (previously hard It has become possible to freely select materials (materials that are less deformable), and it has become possible to make them from plastic materials and other materials to reduce weight. Furthermore, since the cam plate is formed in a semicircular shape, it requires less space inside the lens barrel, and the remaining space can be used to place other parts, making it possible to use the space effectively. Can be made smaller.

According to the embodiment, the semicircular cam plate 14 is connected to the circumferential surface 11a of the main body 11 and the circumferential surface 12 of the mount 12.
Since the engaging part 14a of the cam plate 14 is held in the notch part 11b of the main body 11, the cam plate 14 is arranged between the aperture setting ring 13 and the aperture setting ring 13. The deformation caused by the external force of the engaging part 1
Even if it is transmitted through 3a and 14a, it will not be deformed, and will not adversely affect the control of the aperture blades and will not change the aperture diameter. Furthermore, since the cam plate 14 has a semicircular shape, the space inside the lens barrel can be used effectively, and other parts and electronic components can be placed in the space outside the operating range of the cam plate 14, which improves functionality. An improved lens barrel can be obtained.

[Brief explanation of the drawing]

Figures 1 to 3 show embodiments of the present invention;
2 is a cross-sectional view of the lens barrel, FIG. 2 is another cross-sectional view of the lens barrel shown in FIG. 1, and FIG. 3 is an exploded perspective view of the aperture device of the lens barrel. Brief explanation of the symbols, 11...Main body, 13...Aperture setting ring, 12...Lens mount, 14...
...Cam plate, 15, 16, 17...Aperture unit.

Claims (1)

[Scope of Claim for Utility Model Registration] In a lens barrel aperture device that opens and closes aperture blades provided between an aperture drive plate and a support plate, the aperture blades are rotated around the optical axis in conjunction with an externally operable aperture setting ring. a cam plate formed in a semicircular shape that moves and determines the amount of movement of the aperture blades according to the amount of movement of the aperture setting ring; and a first cam plate that guides the outer periphery of the cam plate when the cam plate rotates. The cam plate includes a guide member and a second guide member that guides the inner circumference of the cam plate when the cam plate rotates, and the cam plate is disposed between the first guide member and the second guide member. A diaphragm device featuring: