| 摘要 |
A control mechanism, free from play and axial tilt, for focusing a lens system (1 to 6) shifts axially a component lens (2). This is held in a ring mount (9) having three guide ribs (9a) guided in slots in a carrier ring (8) to engage in a multistart thread on the inner face of the supporting tube (7). Turning the operating ring (10) results in an axial shift of the lens (2) in its mounting (9) a distance limited by a stop ring (11). The stop ring has internal projections with an internal diameter smaller than the outer diameter of the guide rib (9a) and segments (14) on the carrier ring (8) to engage in the larger diameter segments between them. |
