JPH06160688A - Lens barrel body formed by using metallic mold - Google Patents

Abstract

PURPOSE:To facilitate the drawing of metallic molds and to form plural cam surfaces of a projecting shape having high accuracy by providing the cam surfaces formed so as not to overlap on each other toward the draft direction of the molds. CONSTITUTION:An arrow H is the draw direction of the metallic molds. The cam surface F and the cam surface G are so disposed as not to overlap on each other toward the direction H. The formation of the plural cam surfaces on the lens barrel body is possible by using molds as the lens barrel body is designed in such a manner. Even more, the cam surfaces do not overlap on each other to the direction H and, therefore, the metallic molds are simplified, the drawing is facilitated and the accuracy of the formation is improved. Namely, lenses are provided within the lens barrel body in such a manner that the lenses are guided by the cam surfaces F and G, by which the two lenses are moved along the focal direction of the lenses to the positions guided by the respective cam surfaces according to the rotation of the lens barrel body. The formation of >=3 cam surfaces is possible as well if these cam surfaces do not overlap on each other toward the draw direction H of the molds.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel for a video camera or the like which uses a mold and whose cam surface is formed by molding.

[0002]

2. Description of the Related Art Conventionally, when forming a cam surface on a cam ring, after forming the cam ring, grooves or holes are formed in the cam ring as shown in FIG. 6 to form the cam surface.

When the cam surface is formed by molding, only one surface A is formed as shown in FIG. 5 in order to obtain high dimensional accuracy.

[0004]

However, in the above-mentioned conventional example, if the cam surface having the same function as that shown in FIG. 5 is formed and used by molding, undercutting occurs and the method of removing the die becomes complicated. there were.

The present invention has been made in view of the above-mentioned conventional example, and an object thereof is to provide a lens barrel using a mold, which can easily remove the mold and can form a cam surface with high dimensional accuracy. To do.

[0006]

In order to achieve the above object, the lens barrel of the present invention has the following structure. A lens barrel body formed by using a mold, comprising a plurality of convex cam surfaces which are formed so as not to overlap with each other in a mold drawing direction.

Further, the lens barrel body is formed by using a mold, and is provided with a convex portion having two cam surfaces that face each other in the direction of removing the mold.

[0008]

With the above construction, a plurality of delicate cam surfaces can be formed on the lens barrel by using a simple mold.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view of a lens barrel for a video camera according to an embodiment of the present invention. In the figure, the arrow H indicates the direction of die removal. As can be seen from FIG. 2, the cam surface F and the cam surface G are arranged so as not to overlap each other in the direction H. By making the lens barrel structure like this,
A mold can be used to form multiple cam surfaces on the barrel. Moreover, since the cam surfaces do not overlap with each other in the direction H, the die becomes simpler and easier to pull out, and the forming accuracy is improved.

By providing the lens so as to be guided to the cam surfaces F and G inside the lens barrel shown in FIG. 1, the two lenses are guided by the respective cam surfaces as the lens barrel rotates. In addition, it can be moved along the focal direction of the lens.

Although the number of cam surfaces is two in the above example,
If there is no overlap in the die pulling direction H, set the cam surface to 3
Of course, it is possible to form more than one.

[0013]

Other Embodiments As another embodiment, a lens barrel for a video camera having a cam surface as in the previous example will be described.

FIG. 3 is a sectional view of this embodiment. Two cam surfaces D and E are formed in one lens barrel. In this case, there is only one convex portion in the lens barrel, and both surfaces of the convex portion are used as cam surfaces facing different directions.

FIG. 4 is a diagram showing an example of a state in which components such as a lens are incorporated in the video camera barrel 40 of FIG. In the figure, 41 and 44 are lens frames, and 42 and 4.
Reference numeral 5 is a lens fitted in the frame. Guide pins 43 and 46 are fixed to the respective lens frames, and the pin 43 is in contact with the cam surface E and the pin 46 is in contact with the cam surface D.
The two lenses are attracted to each other by a spring 47, which forces each guide pin against the cam surface. Reference numerals 46 to 48 are guide rails for the lens frame, and keep the lens from rotating as the lens barrel 40 rotates. With the above configuration, when the lens barrel 40 is rotated, the guide pins slide on the cam surfaces D and E, and the two lenses move in the front-rear direction of the lens barrel 40 along the cam surfaces.

By constructing the lens barrel as described above, there are advantages that a simple mold can be used for mold formation, the precision is improved, and the mold can be easily removed.

[0017]

As described above, the lens barrel of the present invention has an effect that a mold can be easily removed and a cam surface having high dimensional accuracy can be formed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a lens barrel that is an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a lens barrel that is an embodiment of the present invention.

FIG. 3 is a cross-sectional view of a lens barrel that is another embodiment of the present invention.

FIG. 4 is a view of an example in which a lens is incorporated in a lens barrel which is another embodiment of the present invention.

FIG. 5 is a cross-sectional view of a conventional lens barrel.

FIG. 6 is a cross-sectional view of a conventional lens barrel.

[Explanation of symbols]

 41 and 44 lens frames, 42 and 45 lenses, 47 springs, 43 and 46 guide pins, and D and E cam surfaces.

Claims (4)

[Claims] 1. A lens barrel body formed by using a mold, comprising a plurality of convex cam surfaces formed so as not to overlap with each other in a direction of removing the mold. A lens barrel using the mold. 2. The lens barrel according to claim 1, wherein the plurality of cam surfaces move the lens group along the focal direction for each cam surface. 3. A lens barrel body formed by using a mold, comprising: a convex portion having, as a cam surface, two surfaces facing each other in the direction of removing the mold. 4. The lens barrel according to claim 3, wherein the two cam surfaces are biased in a direction in which the lens groups are attracted to each other along the cam surfaces.