JPH11167142A - Mount cap for interchangeable lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent oil from adhering to the end face of a cylindrical part opposed to a connection mount surface even when the end face is left as it is attached to the connection mount surface for a long time by providing a small projection for preventing the tight contact of the end face and the connection mount surface on the end face. SOLUTION: In this mount cap for an interchangeable lens; the small projection 24 is formed on the end face 22T of the flat cylindrical part corresponding to the position of a cap-side bayonet pawl 23. By turning the mount cap for the interchangeable lens in a state where the rear part of an interchangeable lens is covered with the mount cap, the end face 22T approaches to the connection mount surface 11 by the action of the tapered surface 23T of the pawl 23. However, the small projection 24 abuts on the end face 22T of the cylindrical part 22, so that a small gap 25 is formed between the end face 22T and the connection mount surface 11. Therefore, air inside and outside the interchangeable lens circulates through the gap 25, whereby trouble that the oil adheres to the end face 22T is not caused.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mount cap for an interchangeable lens, which is mounted on a connection mount side of an interchangeable lens for a single-lens reflex camera with a body.

[0002]

2. Description of the Related Art A flat bottomed cylindrical interchangeable lens mount cap protects a lens on a rear connection mount side when an interchangeable lens is detached from a camera body and prevents dust from entering. Widely used for purposes.

[0003] This interchangeable lens mount cap has not caused any special problems in the past. However, with recent AF interchangeable lenses for single-lens reflex cameras, if it is left on the connection mount surface for a long period of time, it will have a flat bottomed shape. It has been clarified that there is a problem that oil is thinly attached to the end surface of the cylindrical portion.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to solve this newly generated problem, that is, an interchangeable lens in which oil does not adhere to the end surface of a cylindrical portion even when left attached to a connection mounting surface for a long time. It is intended to obtain a mount cap for use.

[0005]

SUMMARY OF THE INVENTION The present inventors have studied the cause of the oil adhering to the end face of the cylindrical portion of the mount cap for interchangeable lenses, and have reached the following conclusion. In the conventional interchangeable lens for a single-lens reflex camera, the movable portion is substantially only the helicoid portion and the aperture mechanism, and the amount of oil used is small. However, an AF-compatible interchangeable lens for a single-lens reflex camera has a large amount of oil enclosed therein due to the presence of a gear mechanism and the like inside. The end surface of the cylindrical portion of the conventional shallow bottomed lens cap is in close contact with the connection mount surface and does not allow air to flow, so the oil vaporized inside the interchangeable lens barrel causes the cylindrical portion It accumulates on the end face.

Based on the above analysis, the present invention focuses on the possibility that such a problem will not occur if air can flow between the end surface of the cylindrical portion of the lens cap and the connection mounting surface. This has led to the invention. That is, the present invention provides a flat-bottomed interchangeable lens mount cap with a bottom that is mounted on the side having a connection mount surface with the body of the interchangeable lens for a single-lens reflex camera. A small projection for preventing the end face from being in close contact with the connection mounting face.

As the mount type of the interchangeable lens, a screw mount type having a connection screw with the body and a bayonet type having a plurality of lens-side bayonet claws for connecting to the body are known, but the bayonet type is mainly used. It is. Therefore, the mount cap for the interchangeable lens is also provided with a plurality of cap-side bayonet claws that engage and disengage with the lens-side bayonet claws. In this case, it is preferable that the small projection is provided corresponding to the position of the cap-side bayonet claw.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The interchangeable lens 10 has a connection mounting surface 11 on the outer periphery of a rear portion thereof, which is in close contact with a connection mounting surface of a camera body. A claw 12 is provided. As is well known, this lens-side bayonet claw 12
Engages with the bayonet claw on the body side to bring the connection mount surface 11 into close contact with the connection mount surface on the body side.

On the other hand, the interchangeable lens mount cap 20 made of a synthetic resin has a bottomed flat cylindrical shape having a bottom surface 21 and a flat cylindrical portion 22, and an end surface 22 of the flat cylindrical portion 22.
T faces the connection mounting surface 11. The mount cap 20 is provided with a cap-side bayonet claw 23 corresponding to the lens-side bayonet claw 12. When the cap-side bayonet claw 23 is rotated relative to the lens-side bayonet claw 12 in a state of engagement with the lens-side bayonet claw 12, the interchangeable lens mount cap 20 is moved in the direction in which the end face 22T approaches the connection mount surface 11. A tapered surface 23T (FIG. 3) for relative movement is provided on the 10 side.

The interchangeable lens mount cap 20 includes
Further, the cap-side bayonet claw 23 is provided on the end face 22T.
Small projections 24 are formed corresponding to the positions of. FIG.
, The height t of the small projections 24 is exaggerated.

The interchangeable lens mount cap 20 having the above-described configuration is placed over the rear part of the interchangeable lens 10, and is relatively rotated with respect to the interchangeable lens 10 so that the lens-side bayonet claw 12 and the cap-side bayonet claw 23 are engaged. When you move
By the action of the tapered surface 23T of the cap-side bayonet claw 23, the end surface 22T approaches the connection mounting surface 11.
However, the small protrusion 24 exists on the tapered surface 23T, and the small protrusion 24 comes into contact with the end surface 22T of the cylindrical portion 22, so that the height of the small protrusion 24 is located between the end surface 22T and the connection mounting surface 11. A slight gap 25 corresponding to the length t is formed. Therefore, the air inside and outside the interchangeable lens 10 can flow through the gap 25, so that an accident that oil adheres to the end face 22T does not occur. In fact, when we experimented,
The phenomenon that oil adhered to 2T did not occur.

The actual height t of the small projections 24 is
In order to prevent dust from entering through the gap 25 caused by the gap, it is preferable to set as small as possible in consideration of the collapse (deformation) of the synthetic resin material. Specifically, several tenths of meters
An order of m is sufficient.

[0013]

According to the mount cap for an interchangeable lens of the present invention, the end face of the cylindrical portion opposed to the connection mount surface has:
The phenomenon that oil adheres can be prevented.

[Brief description of the drawings]

FIG. 1 is a side view showing a cross section of an upper half of an interchangeable lens equipped with a lens cap according to the present invention.

FIG. 2 is a view taken in the direction of the arrow II in FIG.

FIG. 3 is a diagram in which the height of the protrusion is exaggerated in the view of the line III-III in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Interchangeable lens 11 Connection mounting surface 12 Lens side bayonet claw 20 Interchangeable lens mount cap 21 Bottom surface 22 Flat cylindrical part 22T End surface 23 Cap side bayonet claw 23T Tapered surface 24 Small protrusion 25 Gap t Small protrusion height

Claims (2)

[Claims] 1. A flat-bottomed interchangeable lens mount cap with a bottom attached to a side having a connection mount surface with a camera body of an interchangeable lens for a single-lens reflex camera, wherein a cylindrical portion facing the connection mount surface is provided. A mount cap for an interchangeable lens, wherein a small projection is provided on an end face of the end cap to prevent close contact between the end face and a connection mount face. 2. The interchangeable lens mount cap according to claim 1, wherein the interchangeable lens has a plurality of lens-side bayonet claws for connecting to a body, and the interchangeable lens mount cap has the lens-side bayonet claws. A mount cap for an interchangeable lens having a plurality of cap-side bayonet claws engaged with and disengaged from each other, wherein the small projections are provided corresponding to the positions of the cap-side bayonet claws.