GB920850A - An objective lens mounting for projectors - Google Patents

Abstract

920,850. Objective lens mounting for projectors. KAMERAUND KINOWERKE DRESDEN VEB. Dec. 6, 1960, No. 41956/60. Class 97 (1). An objective lens mounting for projectors, comprises a carrier for attachment to the projector, and a first cylindrical sleeve slidable and rotatable within said carrier and capable of receiving by means of a screw thread or bayonet connection an interchangeable objective lens, or an intermediate sleeve supporting said objective lens, said first sleeve being provided with a helical groove or slot terminating in stops, into which groove or slot there extends a pin against which said stops abut when the objective lens, or the objective lens together with the intermediate sleeve, is rotated for removal thereof from or insertion into the first sleeve. As shown, an objective lens 20, releasably secured in an intermediate tube 19 by means of a screw 21, is exchangeably fitted to an adjustable focusing sleeve 5 by means of threading 18 (as illustrated) or alternatively by means of a bayonet connection. Sleeve 5 is provided for coarse focusing purposes with a cam groove 6 engaged by a pin 9 and, for fine focusing purposes, this pin 9 is eccentrically mounted on a shaft 10 rotatably coupled to a reversible motor 13 by way of worm gearing 12, 11. A flange portion 14 of the gear 11 is provided with two index marks 15 which indicate (when either of them is visible through a window 16 in projector housing 1) that the pin 9 of the fine focusing adjustment is in a correct starting position. The coarse focusing is effected manually on rotation of a milled ring 22 on the objective lens 20, whereas fine focusing may be effected remotely through the motor 13.