JPH0460622A - Optical equipment - Google Patents

Abstract

PURPOSE:To reduce the cost and to prevent a flash from being formed by grinding the mounting lug part of a mount by machining after molding using plastic, and obtaining the specific thickness of the mounting lug part. CONSTITUTION:The lens mount 1 is molded out of plastic and the mounting part 1b is ground by machining to obtain the mounting lug 1b which has the specific thickness. Further, the molded lens mount 1 is molded with a movable pattern plate 23 which is moved away from a fixed pattern plate 20 as shown by an arrow 24 and the opening direction of this movable pattern plate 23 is the optical axis direction of the lens mount 1. Further, the mounting lug part 1b is molded with only the movable pattern plate 23 which is opened in the optical axis direction, and is a block body which has a surplus part so that a part to be ground secondarily is minimum. Consequently, the cost is reduced and no flash is formed on a reference surface in the optical axis direction nor a reference surface in a radial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to optical equipment such as a camera body having a mount, an interchangeable lens, an intermediate tube, and various conaverters.

[Prior Art] Conventionally, mounts provided on camera bodies and interchangeable lenses have been made by cutting metal materials.

On the other hand, although it is still at the level of a proposal, it was proposed in 1983 that a mount for an interchangeable lens could be molded from plastic.
No. 38628 is known.

[Problems to be Solved by the Invention] A mount for an optical device has a mount claw protruding in the radial direction (direction perpendicular to the optical axis), and the method for forming this mount claw is difficult.

If molding is performed using a split mold that radially cuts out only the region where the mount claw is located (usually three locations), the mount claw itself can be molded without any problem, but the mount sliding surface (standard in the optical axis direction) It is difficult to realize this because there is a possibility that firmness may occur on the surface (which becomes the surface).

[Means for Solving the Problems] The present invention includes molding the mount from plastic, and then
By cutting the mount claws by machining, we obtained the mount claws with a predetermined thickness, so the mold structure itself during mount molding is simple, and the low cost that is the advantage of plastic molding is maintained. can. In addition, molding can be performed using only a movable mold plate that moves in the optical axis direction relative to a fixed mold plate, without using a split mold that punches out in the radial direction (perpendicular to the optical axis). Also, there is no occurrence of cracks or the like on the radial reference surface.

[Embodiment] FIGS. 1 to 3 show an embodiment of the present invention, and FIG. 1 shows the state of a bayonet type lens mount after molding. FIG. 2 shows an enlarged view of part A (mount claw part) of the mount shown in FIG. FIG. 3 is an enlarged detailed view of section A in FIG. 1 in which the mount claw shown in FIG. 1 has been lathed in the circumferential direction to form a bayonet claw. In Figure 1, 1
is a bayonet type lens mount, 1a is the mount sliding surface that slides into contact with the main mount during attachment and detachment and serves as a reference surface in the optical axis direction for attachment, lb is the bayonet claw that becomes the bayonet claw after completion, lc is the mating mount 1d is the stepped surface, 1e is the cylindrical part that becomes the introduction part of the bayonet claw part of the mating mount, If is A hole is used to tighten the screw for fixing the lens mount to the lens body, and Ig is a groove for positioning the lens mount in the rotational direction when attached to the mating mount.

In Fig. 2, 1h is an inclined surface provided at the intersection of bayonet claw part 1b and cylindrical part le, Ik is a waste portion cut off by lathe processing, and 11 and 1j are stepped surfaces 1d from waste portion 1.
This is an inclined surface provided at the intersection of the two.

FIG. 3 shows a state in which the bayonet claw 1b' has been completed by turning the waste portion 1 shown in FIG.

Figure 4 shows the lens mount l shown in Figures 1 and 2.
The mold structure for molding is shown.

As shown in the figure, the lens mount 1 as a molded product has a movable mold plate 23 that opens in the direction of an arrow 24 with respect to a fixed mold plate 20.
molded by. The opening direction of the movable mold plate 23 is the optical axis direction for the lens mount l, and the parting line is not located on the mount sliding surface 1a and the fitting surface 1c, where occurrence of cracks etc. would be a problem. This results in a surface with high precision and no occurrence of paris. In addition, 21 is a pin gate, and 22 is a spool.

The characteristic feature of this molding is that the mount claw part 1b can be molded only by the movable template 23 that opens in the optical axis direction, and the block body is provided with a dead wall part so that the secondary cutting part is minimized. (I got rid of the undercut). If an attempt was made to obtain the original bayonet claw by molding, a split mold structure would be required that slides (in the direction perpendicular to the optical axis) only in the area of the bayonet claw. In this case, naturally, the parting line will be located on the mount sliding surface or the fitting surface, resulting in the problem of occurrence of cracks.

In this embodiment, the accuracy of the mount sliding surface 1a and the fitting surface 1c,
Prioritizing quality, the actual shape of the mounting claws is later obtained by cutting, which not only improves accuracy and quality, but also lowers the overall cost compared to using split molds.

Furthermore, since the parting line is not exposed on the outside of the mount, it is possible to provide a mount that is also aesthetically pleasing.

In addition, in consideration of the cutting of the mount claw portion 1b, the portions that will become the ends after cutting are made into inclined surfaces 1h, 1j, ]j.
It was also possible to suppress the occurrence of cracks at the ends as much as possible. In addition,
The amount of cutting was also made so as not to reach the stepped surface 1d and the cylindrical portion 1e, so that the cutting surface itself was completely hidden behind the bayonet claw 1b', making it inconspicuous.

Also, for installation, use holes for screws and 11g for positioning.
It was also easy to mold the material, and the degree of freedom in its position was also increased.

FIG. 5 shows a state in which the above-mentioned lens mount l is attached to an interchangeable lens body 30 as an optical equipment body.

In the figure, 32 is a guide bar, and the front group lens frame 3
4 and the rear group lens frame 36 are supported movably in the optical axis direction by the guide /(-32. Note that the 0-0 line represents the optical axis.

[Effects of the Invention] The present invention relates to an optical device having a mount, and when the mount is molded from plastic, the mount claws are formed later by cutting, thereby reducing the cost and preventing the formation of paris on the reference surface. An optical device using a mold structure is provided.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of only a lens mount as an embodiment of the present invention. FIG. 2 is an enlarged view of section A in FIG. 1. FIG. 3 is an enlarged view of section A in FIG. 1 after cutting. FIG. 4 is a sectional view showing the mold structure for molding. FIG. 5 is a sectional view of the lens mount attached to the interchangeable lens body. ■...Lens mount, 1a...Mount sliding surface, 1b...Mount claw part before cutting, lb'...Mount claw.

Claims (4)

[Claims] (1) An optical device having a mount molded from plastic, wherein the mount claw portion of the mount is molded from plastic and then cut by machining to obtain a predetermined thickness of the mount claw portion. device. (2) In an optical device having a mount molded from plastic, the mount is first integrally molded with a movable mold plate that moves in the optical axis direction with respect to a fixed mold plate, and later the mount claws are attached to the actual mount. An optical device characterized in that it is formed by scraping off by mechanical cutting, leaving a thickness of the nail. (3) The optical device according to claim 1 or 2, wherein the amount of cutting of the mount claw portion by the machining is such that it has a diameter larger than that of the circumferentially adjacent circumferential surface. (4) The optical device according to claim 1, (2) or (3), wherein the mount claw portion before being cut by the machining process has a tapered surface formed at an end portion.