Camera body, lens barrel and lens-interchangeable camera

A lens barrel capable of being attached and detached to and from a substantially circular opening formed in a front side of a camera body, wherein said camera body includes a plurality of body-side bayonet lugs which are provided on a peripheral edge of said opening and project toward an inner peripheral side, a circular arc protrusion is positioned inside the camera body and projects forwardly, a protrusion which is fixedly provided on said peripheral edge of said opening at a position in a circular-arc opening provided between adjacent body-side bayonet lugs of the body-side bayonet lugs, a body-side mount surface and a recess-shaped circular arc space is defined between the circular arc protrusion and the body side mount surface,

• a cylindrical portion extending rearwardly from said lens barrel, said cylindrical portion being positioned in the recess-shaped circular-arc space when said lens barrel rotates said lens barrel comprising:
• a plurality of lens-side bayonet lugs which are provided at a rear end of said cylindrical portion and project toward an outer peripheral side, each of said lens-side bayonet lugs being longer than a distance between said protrusion and either of adjacent two body-side bayonet lugs of said body-side bayonet lugs, and being positioned at different circumferential positions from said protrusion when positioned immediately behind said body-side bayonet lugs;
• a recessed portion which is provided on an outer edge of one of said lens-side bayonet lugs, and in which the protrusion of the camera body is loosely engaged when each said lens-side bayonet lugs is positioned in a corresponding said circular-arc opening;
• and
• a lens-side mount surface which comes into contact with said body-side bayonet surface from the front side when said lens-side bayonet lugs are positioned immediately behind said body-side bayonet lugs.

A lens-interchangeable camera comprising:

• a camera body which includes a plurality of body-side bayonet lugs which are provided on a peripheral edge of an opening formed in a front side of said camera body and project toward an inner peripheral side, a protrusion which is positioned in a circular-arc opening formed between adjacent body-side bayonet lugs of said body-side bayonet lugs, and a body-side mount surface;
• and
• a lens barrel which includes a cylindrical portion extending rearward from said lens barrel, a plurality of lens-side bayonet lugs which are provided at a rear end of said cylindrical portion and project toward an outer peripheral side, each of said lens-side bayonet lugs being longer than a distance between said protrusion and either of adjacent two body-side bayonet lugs of said body-side bayonet lugs, and being positioned at different circumferential positions from said protrusion when positioned immediately behind said body-side bayonet lugs;
• a recessed portion which is formed on an outer edge of one of said lens-side bayonet lugs, and in which said protrusion is loosely engaged when each said lens-side bayonet lugs is positioned in a corresponding said circular-arc opening;
• and a lens-side mount surface which comes into contact with said body-side bayonet surface from the front side when said lens-side bayonet lugs are positioned immediately behind said body-side bayonet lugs;
• wherein said body-side bayonet lugs have a circular-arc shape, and
• wherein said camera body comprises a circular arc protrusion which is positioned inside said camera body and projects forward, said circular arc protrusion being spaced toward said inner peripheral side from one of said circular-arc openings on which said protrusion is not provided and two of said body-side bayonet lugs that are adjacent to said one of circular-arc openings on which said protrusion is not provided, and said circular protrusion being concentric with said body-side bayonet lugs, and
• wherein a recess-shaped circular-arc space is defined between said circular arc protrusion and said body-side mount surface so that said cylindrical portion is positioned in said recess-shaped circular-arc space, when said lens barrel rotates.

A lens-interchangeable camera comprising:

• a camera body which includes a plurality of body-side bayonet lugs which are provided on a peripheral edge of an opening formed in a front side of said camera body and project toward an inner peripheral side, a plurality of body-side circular-arc openings which are formed between said body-side bayonet lugs that are adjacent to one another, a circular arc protrusion is positioned inside the camera body and projects forward a body-side mount surface and a recess-shaped circular arc space is defined between the circular arc protrusion and the body side mount surface;
• and
• a lens barrel which includes a plurality of lens-side bayonet lugs which are provided at a rear end of said lens barrel and project toward an outer peripheral side, a plurality of lens-side circular-arc openings which are formed between said lens-side bayonet lugs that are adjacent to one another, a lens-side mount surface which comes into contact with said body-side bayonet surface from the front side when said lens-side bayonet lugs are positioned immediately behind said body-side bayonet lugs and a cylindrical portion extending rearwardly from said lens, said cylindrical portion being positioned in the recess-shaped circular-arc space when said lens barrel rotates,
• wherein one of
• a recessed portion is formed on one of said lens-side bayonet lugs, and a protrusion, which is loosely engaged in said recessed portion when each said lens-side bayonet lugs is positioned in corresponding one of said body-side circular-arc openings and which is positioned at a different circumferential position from said lens-side bayonet lugs positioned immediately behind said body-side bayonet lugs, is provided in one of said body-side circular-arc openings, wherein a distance between said protrusion and either of adjacent two body-side bayonet lugs of said body-side bayonet lugs is shorter than each of said lens-side bayonet lugs, and
• a recessed portion is formed on one of said body-side bayonet lugs, and a protrusion, which is loosely engaged in said recessed portion when each said body-side bayonet lugs is positioned in corresponding one of said lens-side circular-arc openings and which is positioned at a different circumferential position from said body-side bayonet lugs positioned immediately in front of said lens-side bayonet lugs, is provided in one of said lens-side circular-arc openings, wherein a distance between said protrusion and either of adjacent two lens-side bayonet lugs of said lens-side bayonet lugs is shorter than each of said body-side bayonet lugs;
• and
• wherein the number of said body-side bayonet lugs and the number of said lens-side bayonet lugs are three;
• and
• wherein at least one of said three body-side bayonet lugs is different in length from another of said three body-side bayonet lugs,
• wherein said protrusion is positioned in one of three of said circular-arc openings that is the greatest in length,
• wherein at least one of said three lens-side bayonet lugs is different in length from the other of said three lens-side bayonet lugs, and
• wherein said recessed portion is formed on one of said three lens-side bayonet lugs that is the greatest in length.