JP3878336B2 - Lens mount - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an interchangeable lens mount for a system camera, particularly a single-lens reflex camera, and more particularly to a reinforcing means for a synthetic resin lens mount.
[0002]
[Prior art]
In place of conventional metal mounts instead of synthetic resin molded mounts, the objectives of low cost and light weight could be achieved, but there were difficulties in mechanical strength. A reinforcing metal ring member inserted into the side mount (for example, Japanese Patent Laid-Open No. 3-236035 “Mounting member for optical device”), a bayonet ring including bayonet claws, and a fixed portion cylinder formed of synthetic resin are connected. Some mounts (for example, Japanese Patent Application Laid-Open No. 6-27520 “Optical equipment”) are available.
[0003]
[Problems to be solved by the invention]
However, in the prior art, the reinforcement of the mount is partial, or the material, processing cost, weight, etc. are not much different from those of the metal mount. Inexpensive and effective measures have been obtained to comprehensively prevent damage to the screw holes and bayonet claws on the mount side for fixing to the lens body from unreasonable operations when impact is applied or when attaching and detaching. There wasn't.
[0004]
[Means for Solving the Problems]
In order to solve such a problem, the present invention divides a portion to be a lens mirror mounting surface including a bayonet claw and a screw hole of a mount, which is concentrated by weight applied to the lens, into a plurality of simple shapes. The lens mount is characterized in that a component formed by a metal plate is disposed for each bayonet claw and a reinforced mount is formed by integral molding of synthetic resin.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the best embodiment of the present invention will be described with reference to the drawings.
[0006]
FIG. 1 is a schematic perspective view of a lens mount according to the present invention, FIG. 2 is a shape and arrangement of its metal reinforcing member, and FIG. 3 is a partial cross-sectional view showing the vicinity of the lens barrel mount. It is indicated by a symbol.
[0007]
In general, the mount of the interchangeable lens in the system camera is located on the end surface of the rearmost part of the lens barrel, and the camera-side mount is located on the forefront of the body so that they can be attached to and detached from each other. As shown in the sectional view of FIG. 1, the lens mount 2 is provided with a plurality of mounting screw receiving portions 1a around the rear end portion of the fixed cylinder 1 which serves as a foundation for supporting the lens and the lens barrel including the holding frame. Are fixed with a plurality of mounting screws 4 through mounting holes 2b provided with seats at positions corresponding to the flange surface 2c.
[0008]
The lens mount 2 has a mounting projection 2d on the inner wall surface, and a light shielding member 9 is attached with screws 5 to prevent light entering the lens barrel, and the lens holding frame and the lens mount 2 at the rear of the lens barrel. It covers the space between the inner wall and the inside.
[0009]
When a lens is attached to the camera, the bayonet claw 2a on the lens side and the bayonet claw 2a on the camera side are screwed into the camera mount 3 drawn with a broken line at a certain angle. The bayonet can be fitted to each other with the claw 3a engaged, and the lens can be coupled to the camera. However, the bayonet of the lens mount 2 is applied by the strong resistance of the leaf spring 3b on the back surface of the bayonet claw 3a of the camera-side mount 3. The back surface 2e of the claw 2a is pushed, and the flange surface 2c of the lens mount 2 is in pressure contact with the flange surface 3c of the mount 3 on the camera side.
[0010]
In this manner, the lens attachment / detachment operation repeatedly presses and slides the flange surface 2c of the lens mount 2 and the back surface 2e of the bayonet claw 2a with the flange surface 3c of the camera mount 3 and the leaf spring 3b. On the other hand, when a large load or impact is applied from the outside to the lens barrel with the lens attached, the bayonet from the back surface 2e of the bayonet claw 2a of the lens mount 2 that is in contact with the leaf spring 3b of the bayonet claw 3a on the camera side There was a problem that the mounting hole 2b and the mounting screw 4 at the position of the claw 2a and the flange surface 2c were intensively applied, and the bayonet claw 2a or the mounting hole 2b of the synthetic resin molded lens mount was damaged.
[0011]
As shown in FIG. 1, there are three bayonet claws 2a-1, 2a-2, 2a-3 projecting radially at the outer periphery of the wall of the cylindrical portion 2f of the lens mount 2, and the lens barrel is fixed to the flange surface 2c. There are mounting holes 2b-1, 2b-2, 2b-3, 2b-4 in which seats for fixing to the cylinder 1 with mounting screws 4 are formed, and the mounting shape of the structure to be mounted at four places is raised in the embodiment. However, in order to solve the above problem, the back surface 2e-1 corresponding to the back surface of the bayonet claws 2a-1, 2a-2, 2a-3 that is heavy and requires strength to the synthetic resin molded lens mount. 2e-2, 2e-3 and adjacent mounting holes 2b-1, 2b-2, 2b-3, 2b-4 are provided with metal-formed reinforcing members 6, 7, 8 in pairs. , Lens mount integrally molded with synthetic resin Subjected to.
[0012]
Further, the metal forming reinforcing member will be described in detail. As shown in FIG. 2, the metal reinforcing members 6, 7, and 8 are provided with a back surface 2e-1 and a mounting hole 2b-1 with respect to the bayonet claw 2a-1. The reinforcing member 6 is a metal plate that is plastically processed into a U-shaped fan shape so that the flange surface portion 2c-1 is in an opposing position and the two coupling portions thereof are arcuate along the circumference of the cylindrical portion 2f of the lens mount 2. Similarly, the other two of the bayonet claws 2a-2, the back surface 2e-2 and the flange surface portion 2c-2 provided with the mounting holes 2b-2 and 2b-3 are opposed to each other, and the bayonet claws 2a-3, the back surface 2e-3 and the flange surface portion 2c-3 provided with the mounting hole 2b-4 are opposed to each other, and the joint portions thereof are also the circumference of the cylindrical portion 2f of the lens mount 2. It will be arcuate along Metal plates that have been plastically processed into a U-shaped fan shape are used as reinforcing members 7 and 8, respectively, and are arranged radially at the three bayonet claw positions, and integrally molded with synthetic resin so as to form the lens mount 2 as shown in FIG. It is constituted by.
[0013]
When attaching to the fixed barrel 1 of the lens barrel by such a reinforcement structure of the lens mount 2, the attachment screw 4 is fixed through the metal reinforcing members 6, 7, 8, and can be firmly fixed by tightening. The bayonet claws 2a-1 are not only individually reinforced with a metal plate from the back side, but also the concentrated load applied to each bayonet claw due to inadvertent stress during attachment / detachment operation or wearing state. -1, bayonet claw 2a-2 through attachment holes 2b-2 and 2b-3, and bayonet claw 2a-3 through attachment holes 2b-4, individually in a pair of screw receiving portions 1a of fixed barrel 1 of the lens barrel The mechanical strength is further increased.
[0014]
In addition, the flange surface 2c that is slidably contacted with the camera mount 3 when the lens is attached and detached is reinforced by the metal flange surfaces 2c-1, 2c-2, and 2c-3 of the reinforcing members 6, 7, and 8, and the bayonet claw 2a- 1 corresponds to the metal surface of the back surface portion 2e-1, the bayonet claw 2a-2 corresponds to the metal surface of the back surface portion 2e-2, and the bayonet claw 2a-3 corresponds to the metal surface of the back surface portion 2e-4. The problem can be solved.
[0015]
Since the reinforcing members 6, 7, and 8 have simple shapes, plastic processing by a metal plate is easy, the processing costs and material costs are low, and the reinforcement of the lens mount of the present invention that increases the mechanical strength without greatly increasing the weight. The effect of the structure is enormous.
[0016]
【The invention's effect】
As described above, the part where the load is concentrated is a metal reinforcing part processed by plastic working, and the bayonet type mount integrally molded with synthetic resin improves the mechanical strength of the mount, which is a particularly problematic bayonet claw It is possible to provide a lens mount that can sufficiently withstand practical use by improving the strength of the lens.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a lens mount of the present invention.
FIG. 2 is a perspective view showing a shape of a metal reinforcing member.
FIG. 3 is a partial cross-sectional view showing the vicinity of a lens barrel mount;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fixed cylinder 1a Screw receiving part 2 Lens mount 2a Bayonet claw 2b Mounting hole 2c Flange surface 2d Mounting projection part 2e Back surface 2f Cylindrical part 3 Camera mount 6 Reinforcement member 7 Reinforcement member 8 Reinforcement member 9 Light shielding member

Claims (1)

In the bayonet type lens mount having a bayonet claw in which a plurality of radially projecting portions are formed on the outer periphery of the cylindrical wall of the mount mechanism that enables the lens to be attached to and detached from the camera body, The back surface portion of the bayonet claw of the lens mount and the surface including the lens body mounting hole corresponding to the flange surface of the lens are opposed to each other, and the two coupling portions thereof are along the circumference of the cylindrical portion of the lens mount. A lens mount characterized in that a metal reinforcing member formed in a U-shaped fan shape that has an arc shape is installed at the bayonet claw position and is integrally formed of synthetic resin.

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