JPH03223805A - Interchangeable lens barrel - Google Patents

Abstract

PURPOSE:To prevent the interchangeable lens barrel from increasing is size even when a plate cam is incorporated by molding a mount for attachment to and detachment from a camera main body out of plastic and supporting a guide rod by a support member which is molded integrally with the mount. CONSTITUTION:One end of the guide rod 3 is pressed in the hole of the boss 1b of the bayonet mount 1 so that it does not comes out with ease. A plate 2 which is positioned at a position is correct relation with a hole 2b where a positioning projection 1c is inserted is fixed to the end part of the support member 1a of the bayonet mount 1 with a screw 11. Further, the other end of the guide rod 3 is supported while fitted in the hole 2a of the plate 2, the center hole 4a of the cam plate 4 is inserted and supported a screw 5 fixed to the support member 1a, and a cam plate 4 is rotatable on the screw 5. Consequently, even when an inexpensive cam plate 4 is used as the cam member, the lens barrel does not become large in size.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an interchangeable lens barrel whose mount is molded from plastic.

[Prior Art] Conventionally, a lens barrel in which a movable lens is held by a guide rod and guided in movement has been commonly used in lenses for video cameras.

Regarding the method of holding the guide rod,
As described in No. 290, a disc-shaped base plate is fixed to both ends of a cylindrical fixed tube, and the guide rod is held by the base plate. Further, as described in Japanese Patent Publication No. 58-23603, one end of the lot is directly held by a cylindrical fixed tube, and the other end is held by a base plate fixed to the fixed tube.

[Problems to be Solved by the Invention] However, in the conventional example described above, a cylindrical fixed cylinder is used to hold the guide rod, so the cam device for moving the lens becomes a cylindrical member, and the fixed Together with the tube, this causes high costs. There have been proposals to use a plate-shaped cam plate in a cam device. Is it possible to make the cam plate at a very low cost by press processing?If it is combined with a cylindrical fixed tube, the lens barrel will become larger, etc.
Very easy to implement.

[Means for Solving the Problems] The present invention provides a support for supporting a guide rod as a guide member for a lens group when a mount for attaching and detaching from a camera body is molded from plastic in order to reduce costs. Since the guide rod is also integrally molded, the guide rod can be supported by the support part of the mount, which eliminates the need for a fixed cylinder for supporting the guide rod, which was previously required, and makes it possible to use non-cylindrical cam members such as plate cams. To provide an interchangeable lens barrel that does not need to be enlarged even when incorporated.

[Embodiment] Figs. 1 to 4 show a first embodiment of the present invention, in which Fig. 1 is a cross-sectional view including the optical axis of an interchangeable lens barrel including a bayonet mount, and Fig. 3 is a cross-sectional view including the optical axis of an interchangeable lens barrel including a bayonet mount. FIG. 4 is a perspective view from the front of the main parts of the interchangeable lens barrel shown in the figure, and FIG. 4 is a perspective view from the rear of the same. FIG. 2 is a perspective view of the cam plate shown in FIG. 1.

In Figures 1 to 4, 1 is a bayonet mount made by plastic injection molding, la is a support member integrally molded during molding of the mount and extends in the optical axis direction, and 1b is also a support member of the mount. A boss for press-fitting the lot is integrally formed during molding, and a hole for press-fitting is formed in this boss. The IC has a positioning protrusion, which is formed at the tip of the support member 1a. Reference numeral 2 denotes a guide rod holding plate, in which a hole 2a for supporting the other end of the guide rod 3 is formed. 3 is a guide rod, - all ends are press-fitted and supported by the press-fitting boss Ib,
The other end is supported by being inserted into the hole 2a of the plate 2. 4 is a cam plate, 4a is a rotation center hole of the cam plate, 4b and 4c are cam grooves, 5 is a screw for the rotation axis of the cam plate 4, 6 is a front group lens moving frame, 6a is a sleeve portion of the moving frame 6, 6b is a cam bin integrated with the moving frame 6; 7 is a rear group lens frame; 7a is a sleeve integrated with the lens frame 7; 7b is a cam bin integrated with the lens frame 7; 8 is a front group lens holding frame;
9 is an exterior cylinder, IO is a protective glass, and 11.12 is a screw. Ll is a front group lens, and L2 is a rear group lens.

Next, in the above configuration, one end of the guide rod 3 is tightly press-fitted into the hole of the boss ib of the bayonet mount l so as not to easily come out. The plate 2 is fixed to the end of the support member la of the bayonet mount 1 by screws 11, which is positioned at the correct position in relation to the hole 2b into which the positioning projection 1c is inserted.

The other end of the guide rod 3 is fitted into the hole 2a of the plate 2 and supported. The center hole 4a of the cam plate 4 is inserted and supported by a screw 5 fixed to the support member 1a, and the cam plate 4 is rotatable around the screw 5.

The front group moving frame 6, which holds the front group lens holding frame 8 at its inner diameter with a helicoid screw, is supported by the guide rod 3 by a sleeve 6a so as to be movable in the optical axis direction. The rear group lens frame 7 is also held movably in the optical axis direction by the sleeve 7a or the guide rod 3. The cam pins 6b and 7b protruding from the front group lens holding frame 8 and the rear group lens frame 7 fit into the cam grooves 4b and 4c of the cam plate 4, respectively, without play, and as the cam plate 4 rotates, the lens is moved by the action of the cam. The frames 8 and 7 can be moved in the optical axis direction.

[Other Embodiments] FIG. 5 shows another embodiment, in which 11 is a bayonet mount, l
la is a support member, llb is a boss for press-fitting a rod, and 12 is a guide rod.

Similar to the first embodiment, this embodiment has a guide rod 12 mounted on a bayonet mount 11 made of plastic.
are press-fitted and supported, but if the guide rod is short, the plate 2 shown in the first embodiment can be omitted to further reduce size and cost.

- As explained above, in the above embodiment, the bayonet mount of the interchangeable lens is molded from plastic, and one end of the guide rod, which is the guiding member of the movable lens, is press-fitted into the bayonet mount to ensure the distance between the guide rods. . In the first embodiment, the other end of the guide rod is supported by a plate, so that the distance between lots on the plate side (other end) can also be accurately determined.

As a result of the above, the plurality of guide rods can each maintain a parallel state. In addition, the plate is guided by the positioning protrusion provided at the end of the support member of the bayonet mount, and is fixed in the correct position, thereby preventing the plurality of guide rods from twisting and aligning them parallel to the optical axis. will be corrected. As a result, it is now possible to eliminate the cylindrical fixed tube that was previously necessary, and the guide rod can be press-fitted directly into the bayonet mount, which is the standard for mounting on the camera body, without using other parts. This makes it possible to support the moving lens group with higher accuracy than before. Furthermore, since the cylindrical fixed tube is no longer necessary, an inexpensive cam plate can be used instead of the conventional cylindrical cam tube, which has a significant effect on miniaturization and cost reduction.

[Effects of the Invention] When the mount for attaching to and detaching from the camera body is molded from plastic, the present invention also integrally molds the support portion for supporting the guide rod as a guide member for the lens group. is substantially directly supported by the mount. Therefore, the positional accuracy of the guide rod can be made as high as that of the mount serving as a reference for the optical position, and the lens group can be moved accurately and smoothly.

In addition, by supporting the guide rod with a mount, it becomes possible to eliminate the cylindrical fixed tube that was conventionally required for supporting the kite rod, making it possible to provide a compact interchangeable lens barrel. Moreover, it is possible to provide an interchangeable lens barrel that does not become large in size even if an inexpensive cam plate is used as a cam member.

Furthermore, by integrally molding the supporting member that movably supports the cam plate during the molding of the mount, it is possible to provide an interchangeable lens barrel that is lower in cost and smaller in size.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the interchangeable lens barrel of the first embodiment, and FIG. 2 is a perspective view of only the cam plate shown in FIG. 1. Figure 3 is: A front perspective view of only the main parts of the tS1 diagram, Figure 4 is a rear perspective view of only the main parts of the 1rJ1 diagram, and Figure 5 (A is the second
FIG. 2 is a perspective view showing the main parts of the embodiment. 1 is the bayonet mount la is the support member Ib is the rod press-fitting boss 3 is the guide rod 4 is the cam plate 4b, 4c is the cam groove 6 is the front group lens moving frame 7 is the rear group lens frame 6b, 7b is the cam bin 8 is the front group Lens holding frame 100Z

Claims (2)

[Claims] (1) In an interchangeable lens barrel that uses a guide rod parallel to the optical axis as a guide member when moving the lens group in the optical axis direction, a mount for attaching and detaching from the camera body is made of plastic molding. . An interchangeable lens barrel, characterized in that the guide rod is supported by a support portion that is integrally molded during molding of the mount. (2) In an interchangeable lens barrel in which a guide rod parallel to the optical axis is used as a guide member when moving the lens group in the optical axis direction, and a plate cam is used as the means for moving the lens group. A mount for attaching and detaching is made by molding plastic, the guide rod is supported by a support part integrally molded when the mount is molded, and the plate is supported by a support member integrally molded and extending in the optical axis direction when the mount is molded. An interchangeable lens barrel characterized by supporting a cam.