Patent ID: 8687298

Claim:
A lens barrel comprising: a fixed cylinder; a first rotary cylinder rotatably provided around an axis relative to the fixed cylinder; and a moving cylinder disposed inside of the first rotary cylinder to move integrally with the first rotary cylinder on the axis and rotate around the axis relative to the first rotary cylinder, wherein: the moving cylinder includes a front protrusion group including first, second, and third protrusions protruding outward from an outer circumference of a subject side of the moving cylinder, the first protrusion and the second protrusion being arranged to oppose each other across the axis and the third protrusion being placed between the first and second protrusions, and a rear protrusion group including fourth and fifth protrusions on the outer circumference of the subject side of the moving cylinder at a position closer to an image plane side than the front protrusion group, the fourth and fifth protrusions protruding outward from the outer circumference of the subject side of the moving cylinder, a circumferential width of the fourth and fifth protrusions being twice or more larger than that of the first, second, and third protrusions of the front protrusion group, the fourth protrusion and the fifth protrusion being arranged to oppose each other across the axis and being arranged so that the fourth protrusion overlaps with the first protrusion and the fifth protrusion overlaps with the second protrusion as seen from ahead of the moving cylinder; the first rotary cylinder includes, in an inner circumference, a first circumferential groove formed at a position in association with an axial position of the front protrusion group of the moving cylinder, a second circumferential groove formed at a position in association with an axial position of the rear protrusion group of the moving cylinder, a first guide having three or more depressions into which the protrusions of the front protrusion group are inserted, respectively, extending in parallel to the axis to communicate with the first circumferential groove, and a second guide having two or more depressions into which the protrusions of the rear protrusion group are inserted, respectively, extending in parallel to the axis to communicate with the second circumferential groove; the first, second, third, fourth, and fifth protrusions protrude radially outward from the moving cylinder at an approximately same amount; and the first rotary cylinder and the moving cylinder are coupled with each other by fitting the front and rear protrusion groups into the first and second circumferential grooves, respectively.