Variable magnification device

A variable magnification device capable of varying magnification of projected images of information media which comprises;

• a plurality of interchangeable projection lenses having different focal lengths,
• a change-over means having said projection lenses mounted thereon for selectively bringing said projection lenses into a predetermined projecting position through pivotal rotation thereof, said change-over means being provided with means for guiding the pivotal rotation thereof and means for positioning a selected one of said projection lenses at said predetermined position,
• rotary intermediate means of material having a large coefficient of friction and including toothed portions normally engaging corresponding toothed portions formed in the peripheral portion of lens mounts of said projection lenses, and rotary plate portions integral with said toothed portions of said intermediate means, and
• a rotary focusing adjusting means urged away from said intermediate means by spring means to be normally kept out of contact with said intermediate means and having an engaging portion at the peripheral edge thereof engageable with corresponding engaging portions provided in the peripheral edge of said rotary plate portions of said intermediate means, said focusing adjusting means being arranged to engage, at said engaging portion thereof, said engaging portions of said rotary plate portions of said intermediate means upon depression of said focusing adjusting means toward said intermediate means for adjusting focusing of only the selected one of said projection lenses which has been brought to said predetermined projecting position by the pivotal rotation of said change-over means.

A variable magnification device capable of varying magnification of projected images of information bearing media, comprising:

• a frame;
• a plurality of projection lenses having different focal lengths;
• support means attached to said frame and supporting a desired one of said projection lenses at a predetermined projecting position within said device;
• and focusing adjusting means attached to said frame and normally out of contact with the selected one of said projection lenses and movable for engagement with said selected projection lens when the focus of said selected projection lens is to be adjusted.

A variable magnification device capable of varying magnification of projected images of information bearing media, comprising;

• a frame;
• a plurality of projection lenses having different focal lengths, each of said projection lenses including a movable mounting member for adjusting the focus of said projection lens;
• support means mounted on said frame and supporting said projection lenses and movable to bring a desired one of said projection lenses into a predetermined projection position;
• and focusing adjusting means mounted on said frame and including an engaging member normally out of contact with said mounting member and movable for engagement with said mounting member of the selected one of said projection lens for moving said mounting member for focusing the selected one of said projection lenses.