Patent ID: 7953317

Claim:
A lens barrel comprising: a driven ring which is rotatable about an axis extending in an optical axis direction and movable in said optical axis direction, wherein said axis extending in said optical axis direction defines an axial direction; a follower which is provided on said driven ring; a rotational transfer ring which is driven to rotate about said axis, said rotational transfer ring including a circumferential groove having no axial-direction component, and a rotational transfer groove which is communicatively connected with said circumferential groove and includes an axial-direction component, said follower being selectively engaged in said circumferential groove and said rotational transfer groove; a guide ring which is prevented from rotating about said axis, said guide ring being associated with said rotational transfer ring to allow said rotational transfer ring to rotate about said axis relative to said guide ring and to be prevented from moving in said optical axis direction relative to said rotational transfer ring; and a cam groove formed on said guide ring, in which said follower of said driven ring is engaged, said cam groove guiding said driven ring to move between a non-photographing position and a ready-to-photograph position by a rotation of said driven ring relative to said guide ring, wherein rotation of said driven ring is prevented when said follower is engaged in said circumferential groove so that said driven ring is held at said non-photographing position, wherein, when said follower is engaged in said rotational transfer groove, said driven ring is moved along said cam groove between said non-photographing position and said ready-to-photograph position by a rotation of said rotational transfer ring, wherein said rotational transfer ring includes a pair of opposed wall surfaces in said circumferential groove which extend parallel to each other so as to determine a position of said follower in said optical axis direction when said driven ring moves between said non-photographing position and said ready-to-photograph position, and wherein an entire range, of said cam groove of said guide ring, that is used to move said driven ring between said ready-to-photograph position and said non-photographing position includes an axial-direction component.