Lens tube e.g. for multi-variable photographic objective lens, has engagement lug for gripping and sliding in peripheral groove together with rotation guide projection

摘要

A lens tube has a torsionally resistive ring element (22) having at least one peripheral slot or groove (22d) on its inner peripheral surface, a first ring (18) held in the stationary ring element (22) to rotate about an axis or rotation extending along the optical axis, a second ring (15) which rotates in common with the first ring (18) and relative to the latter is axially movable only, where the second ring (15) has at least one engagement lug (15b) which slidingly grips in the peripheral groove together with a rotation guide projection (18b), A coupling ring (14) is arranged within the two rings, rotationally fixed relative to the annular element (22), and is used to couple the two rings so that they are rotatable to the coupling ring. A coupling device (14c, d; 15d, e) between the coupling ring (14) and the second ring (15) is released in a second angular position of the two rings(15,18).