Patent attributes
An extension spring installation structure of a lens barrel includes relatively movable members, one of which supports an optical element, including an extension coil spring biasing the relatively movable members toward each other; and a spring-hook portion and a tilt-restriction portion formed on a relatively movable members. An engaging portion of the extension coil spring is engaged with the spring-hook portion by movement of the extension coil spring toward the spring-hook portion. The spring-hook portion is shaped so as to be prevented from being disengaged from the engaging portion of the extension coil spring even if moved along the axis of the coil spring portion thereof with the engaging portion engaged with the spring-hook portion. The tilt-restriction portion prevents the coil spring portion from moving in a radial direction of the coil spring portion with the engaging portion engaged with the spring-hook portion.
