GB978770A - Improvements in and relating to photographic lenses - Google Patents

Abstract

978, 770. Focusing lens mounts. AGFA A.G. Sept. 11, 1963 [Sept. 29, 1962], No. 35838/63. Heading G2J. A front lens focusing photographic objective has a main objective mount 1 threaded at 6 to take a correspondingly threaded front lens mount preferably of plastic material which has, combined in a single member 11, a front lens 5, a manual setting flange 15 and the threaded portion 12, the focusing range being defined by a stop on mount 1 having surfaces 8, 9 which co-operate with a ring 17 attached to member 11. In assembling, the metal ring 17 is laid upon mount 1 so that a lug 21 thereon meets stop surface 9, blade springs 7 effecting a resilient positioning of the ring 17. The portion 12 is then screwed into portion 6 until lens 5 assumes a position with respect to the other lens 2 corresponding to one extreme setting of the focusing arrangement. Ring 17 is then secured to member 11 by screws 24 engaging slots 14 and threaded bores 18. The mount 11 may now only be rotated from the position where lug 21 engages surface 9 to the position where another lug 20 engages surface 8. A focusing distance scale ring 25 masks slots 14 and screws 24 and cooperates with a fixed index on the conical surface 16 of mount 1. The ring 17 may have oblique teeth 22 for biting into the member 11 and bores 19 to engage a ball catch 10 in certain focusing positions such as 2 metres, 5 metres, and infinity.