Focusing mechanism for camera objective

Claim 1

In a camera provided with a housing and an objective projecting forwardly from said housing, said objective including a lens barrel centered on an optical axis and a plurality of lenses in said lens barrel, at least one of said lenses being provided with an axially shiftable lens mount, the combination therewith of: stationary bearing means in said lens barrel; a guide rod slidably and nonrotatably held in said bearing means, said guide rod being fastened to said lens mount and extending rearwardly therefrom parallel to said optical axis; a threaded member forming a coaxial rearward extension of said guide rod nonrotatably held in said housing with freedom of axial displacement, said guide rod and said member being relatively axially shiftable; a threaded drive element matingly engaging said member, said element being provided with gear teeth and being held against axial displacement in said housing; a reversible motor provided with a pinion in mesh with said gear teeth; a manually rotatable setting ring carried on said lens barrel in an axially fixed position, said setting ring being provided with a camming groove registering with an axially extending slot in said lens barrel, said lens mount being provided with a projection extending through said slot into engagement with said camming groove; and biasing means urging said guide rod and said member into a predetermined relative axial position, said camming groove and said slot receiving said projection with sufficient play to enable an axial shift of said lens mount by said motor independently of the position of said setting ring, said lens mount being axially entrainable by said setting ring via said projection against the force of said biasing means.