JPS58100805A - Cam structural body for zoom lens - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cam structure in a zoom lens barrel.

An example of the front five parts and the zoom part of a conventional zoom lens barrel will be described with reference to No. 1-. In No. 1-, the zoom unit 12
is rotated on the outside of the fixed ring 7 by an external one-motion operation, and at the same time, the cam l19, which is implanted in the cam jj9 and is rotated by the rJ contact pin 15, is attached to the cam 119 as shown in FIG.
14.15 is formed, and the guide bin IL11 is provided on the cam $14.15 and the cylinder of the guide ring 8.
It passes through the wire and is screwed and fixed to the lens holder 1820.21, and the variable power lens 5.4 and extraction lens 5 are set to the desired position by the rotation direction and -turn angle wrinkles of the zoom 3J12. and the focal length changes.

In this way, the cam groove in a typical zoom lens barrel has two planes parallel to the center line of the guide bin, which always intersects the round axis. L has been cut, and conventionally it has been manufactured using Kinpo tube VHC processing, and it is impossible to break the cam due to molding of synthetic resin because the direction of removal of the metal part cannot be determined. However, they had no choice but to use a process that was expensive, slow, and had low performance. In addition, with conventional cam grooves, since the kite bin comes into contact with both sides of the groove, both Itl and
It was rarely necessary to finish with high precision.

The object of the present invention is to eliminate the drawbacks of the prior art, to provide a highly accurate cam structure that can be molded with synthetic resin, is inexpensive, has a high quantity #i property, and provides a high-precision cam structure.

The feature of the present invention is that when forming the cam surface of the cam groove, the Ktt type in the optical axis direction is pulled out, and the Kaido Binna Mukuro Cam @UK is composed of a pressing plate and an elastic body to always press with a constant pressure. be.

The present invention will be explained below using actual woven examples.

FIG. 3 is a developed view of the cam structure according to the present invention;
The figure is a cross-sectional view.

The cam Is9 is molded from synthetic resin, the mold is pulled out in the optical axis direction to form the cam surfaces 22.25, and the outside of the cam surface 22.25 is made into a cylindrical shape to prevent deformation after molding. A rectangular through hole is provided to attach the protrusion and the elastic body. The pressing plate IS, 19 is cam direction 22.25
It has a cylindrical partial shape that is made smaller by the diameter of the kite bin 10.11 in the optical axis direction #Is, which is generally pierced to form the k, and is fitted with the cam lI9, and the elastic body and j
It has a protruding SV for I#. Elastic body 17.1
8 is provided between the rectangular #1s of the cam ring 9 and the protrusion of the pressing plate 16.19, so that the pressing plate 16.19 always presses the cam surface 22925K against the kite bin 10.11V. Further, the pressing plate can also be easily manufactured by molding.

As explained in detail above, the effects of the present invention are inexpensive,
It is now possible to manufacture a zoom lens cam structure using synthetic resin, which is easy to mass produce.

[Brief explanation of the drawing]

FIG. 1 is a partial view of a general zoom lens shown in an interrupted plane;
FIG. 2 is a developed view of a conventional cam ring, FIG. S is a developed view of a cam structure according to the present invention, and the fourth button is a partial sectional view of the cam structure according to the present invention. 1: Focusing lens 2: Focusing lens 5: Variable magnification lens 4: Seismic magnification lens 5: Correction lens 6
: Lens holding ring 7: Fixed ill 8: Guide ring 9: Cam ll11o: Kite hinge 11 guide bin 12: Zoom product 15: Connecting bin 14: Cam groove 15: Cam # 16: Pressing plate 17: Elastic body 18: Elastic body 19: Pressing plate 20: Lens holding ring 21: Lens holding 1f22: Cam surface 2! 1: Cam surface 1 Figure? 2 town

Claims (1)

[Claims] t To adjust the focal length, use external operation.
In a zoom lens cam structure having a groove V for non-linearly moving at least one of the two lens groups in the optical axis direction and a driven shaft that slides in the groove, one side of the groove is The groove is formed stepwise from the optical axis direction and is used as a reference surface on which the driven shaft slides, and the driven shaft is pressed against the reference surface with a constant pressure. A zoom lens structure comprising a pressing plate and an elastic body.