GB915335A - Improvements in or relating to detachable objective mounts for photographic apparatus - Google Patents

Abstract

915,335. Focusing lens mounts. KAMEBAUND KINOWERKE DRESDEN VEB. Oct. 17, 1960, No. 35481/60. Class 97 (1). A detachable objective mount for photographic apparatus comprises support means adapted for connection to the apparatus housing, a spindle supporting the objective lens carrier and axially adjustable in the support means for focusing, and a rotatable locking- device which, in one direction of rotation, acts to secure the objective mount to the apparatus housing, and in the other direction looks the spindle in relation to the support means. As shown in Fig. 1, the objective lens carrier 3 is rotatably mounted on a spindle 1 and held against axial displacement by parts 4 rigid with spindle 1. The latter extends through a bush 6, in which it has threaded engagement, and through a sleeve 8 rigid with bush 6 and carrying scale markings 9 for focusing purposes in cooperation with markings on the milled head 10 of spindle 1. A ring 12 rotatably mounted on sleeve 8 carries keys 13 for bayonet connection with a corresponding part 21 of the projector, and has a recess 14 (Fig. 3) in which is fixed a leaf-spring 17. A pin 15 extends through a slot in sleeve 8 and, when the objective mount is detached is pressed by leaf-spring 17 against spindle 1 to prevent rotation of the latter and thus preserve the previous focus setting. On attachment to a projector, a groove 2 of the objective carrier 3 is engaged by a pin to prevent rotation, and a key 18 on sleeve 8 engages a corresponding part 20 on the projector to hold sleeve 8 against rotation. As ring 12 is then rotated to make the bayonet connection, the relative movement between pin 15 and the helical boundary of recess 14 releases the constraint on spindle 1 to allow further focusing adjustment.