JPS5939681Y2 - lens barrel - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to an improvement in the structure of a lens barrel.

In the lens barrel of a lens, for example, the lens barrel is separated into an inner barrel and an outer barrel that accommodates the inner barrel, and the inner barrel is further provided with a large hole, or the inner barrel is divided into two parts. If the structure is cut out from two or more parts, there is a risk of light leakage in the large hole or the gap between the joints.
If the inner cylinder is not completely sealed by the outer cylinder, additional means for light shielding and dustproofing are required.

However, in order to block light and prevent dust, it may be possible to insert an additional cylindrical body between the outer tube and the inner tube, but in this case, the lens tube itself becomes larger and heavier. Then, there is an inconvenience.

In particular, the lens barrel of a zoom lens has a special mechanism called a zooming mechanism with a 1% fQ [] in addition to the normal focus adjustment mechanism, so the structure is more complicated than that of a general lens barrel. For this reason, the lens barrel itself tends to be relatively large and heavy, whereas in today's cameras,
In particular, there is a strong trend toward smaller size and lighter weight, and therefore there is a desire for smaller and lighter lenses themselves, as well as simplification of the structure of the lens barrel and lower manufacturing costs. It is also a place that is highly desired.

The present invention was developed in view of the above circumstances, and aims to provide a lens barrel that has a simple structure, can be manufactured at low cost, and can be made smaller and lighter overall. Its features include a movable inner cylinder, an outer cylinder having a large hole through which an operating member for accommodating the inner cylinder and operating the inner cylinder is inserted, and a By arranging a shielding member that closes the hole in the outer tube, and configuring the shielding member to move together with the operating member, light is blocked from the hole in the outer tube into the lens barrel, and dust is prevented. It's what I did.

Hereinafter, as an embodiment of the present invention, an example in which the present invention is applied to a zoom lens barrel having an external operating lever for zooming as described above will be described with reference to the accompanying drawings.

In Figures 1 and 2, 1 is the cine camera body C.
2 is a fixed lens barrel fixed to the holding member 1, and 3 is a zooming lens rotatably fitted into the inner circumference of the lens barrel. The cam ring has, on its outer peripheral surface, a cam portion 7a that controls the movement of the variable magnification lens group G2 in the optical axis direction, and a cam portion 7b that controls the movement of the correction lens group G3 in the optical axis direction. A plate cam 7 is fixed thereto, and the cam ring 3 is connected to the plate cam 7.
Cam part 7. It has escape holes 3a and 3b corresponding to holes i and 7b, and their positions in the forward axial direction are regulated by the holding member 1 and the mask plate 4.

5 is a lens holding frame that holds the variable power lens group G2, 6 is a lens holding frame that holds the correction lens group G3, and their respective implant pins 5a and 5b are inserted through escape holes 3a and 3b of the cam ring 3. The cam portion 7a of the plate cam 7.

7b, respectively.

8, 9.10 are sliding guide shafts fixed parallel to the optical axes of the holding member 1 and the mask plate 4, respectively;
6 is the axis 8. 9.10, it is supported so as to be movable in the optical axis direction.

Reference numeral 11 denotes a single-action operating member for zooming, which is connected to the cam ring 3 and extends to the outside of the lens barrel by passing through a large hole 2a formed in a part of the fixed lens barrel 2. When the operating member 11 is manually operated to rotate the cam ring 3,
Cam portion 7a of plate cam 7.

7b, the variable magnification lens group G2 and the correction lens group G3 are moved in the optical axis direction, thereby obtaining a known zooming effect.

12 is a reinforcing member fixed between the holding member 1 and the mask plate 4 so as to be located inside the cam ring 3 at an angular position corresponding to the hole size 2a of the fixed lens barrel 2; This prevents the cylinder 2 from deforming.

Reference numeral 13 denotes a shielding member for light shielding and dustproofing, which has the shape of a thin strip and is formed larger than the hole size 2a of the fixed lens barrel 2, and is provided between the plate cam 7 and the fixed lens barrel 2. , the operation member 11 is inserted so as to close the hole size 2a.
It is fixed to the plate cam 7 by.

Note that, for example, a black synthetic resin material is suitable for the strip 13.

Reference numeral 14 denotes a female threaded cylinder having multiple threads on its inner peripheral surface, and is fixed to the front end of the fixed lens barrel 2 together with the mask plate 4 and a lubricating oil leakage prevention member 19 formed in a convex annular shape. It is fastened with screws 15.

Reference numeral 16 denotes a male threaded cylinder that holds the focusing lens group G1 and has a threaded part on its outer peripheral surface that can be fitted with the threaded part of the female threaded cylinder 14, and the cylinder 16 has a focusing lens group G1. An operating ring 17 is fastened with a fixing screw 18.

In this invention, since the operating member is based on the tank bottom, the hole size of the outer cylinder is 2a.
Even when moving inward, the large hole 2a is always blocked by the strip 13 of the shielding member, thereby preventing light leakage and intrusion of dust.

As detailed above, in the present invention, the inner cylinder having a large hole and/or a gap is shielded from light and/or dust by a thin strip, so that the inner cylinder is prevented from dust and light.
Compared to a lens barrel whose bottom is made of a cylindrical body with a relatively large wall thickness, the radial dimension can be significantly reduced, and it is much more compact than the conventional one. It can be manufactured at a low cost, and has many effects such as greatly contributing to the reduction in size and weight of the lens barrel itself.

Furthermore, the above-mentioned effects can be achieved by applying the present invention to lens barrels such as various interchangeable lens barrels, camera-incorporated range barrels, and video camera lens barrels.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional perspective view showing the details of the tank bottom of an embodiment in which the present invention is applied to a zoom lens barrel, and FIG. 2 is a full sectional view of FIG. 1. 2: Fixed lens barrel, 3: Zooming cam ring, 5: Variable lens group holding frame, 6: Correction lens group holding frame, 7: Plate cam, 1
1: manual operation member for zooming, 13: dustproof and light shielding strip, G1: focusing lens group, G2: variable magnification lens group,
G3: Correction lens group.

Claims (1)

[Claims for Utility Model Registration] A movable inner cylinder, an operating member fixed to the inner cylinder, and an outer cylinder provided with an elongated hole arranged outside the inner cylinder through which the operating member moves. , disposing a band-shaped shielding member between the inner tube and the outer tube so as to close the elongated hole, fixing the operating portion spring to the inner tube through a through hole provided in the band-shaped shielding member, and A lens barrel characterized in that the strip-shaped shielding member moves together with the operating member to cover the elongated hole as the elongated hole of the operating member moves.