Microfiche reader

A microfiche reader having a turntable supported for rotation about a generally vertical axis coinciding with the axis of an image projecting light beam port therethrough;

• X-Y fiche transport means mounted on said turntable, for rotation therewith a pair of image projecting lenses of different powers and means interconnecting said pair of lenses and operable to shift said lenses in unison to position either one thereof in a nonoperating position to one side of said light beam port and the other one thereof in alignment with said light beam port and resting directly on said X-Y fiche transport means with the focal plane thereof parallel to and precisely spaced from a fiche positioned in said X-Y fiche transport means.

In a microfiche reader of the type having an X-Y fiche transport mounted crosswise of the optical axis of the reader and including projection lamp means at on end of said optical axis and an image display screen at the other end of said optical axis, that improvement which comprises:

• a unitary sub-assembly movably supporting a pair of projection lenses of different powers for simultaneous movement to position either of said lens in alignment with said optical axis and including a lamp intensity control means for automatically maintaining the light intensity of the projected fiche image on the screen uniform irrespective of which one of said lens is positioned in the optical axis.

A dual power lens mounting assembly for a microfiche reader comprising:

• an elongated housing having upwardly diverging camways, slide means shiftable lengthwise of said housing having a pair of fiche projecting lenses of different powers projecting loosely therethrough and spaced apart longitudinally of said housing, support means projecting from the opposite sides of said lens and crosswise of said housing into positions engageable with said camways thereby to lower one of said lens into the fiche projecting position thereof while elevating the other lens out of its fiche projecting position as both lenses are shifted simultaneously lengthwise of said housing, and means in said housing to limit the shifting movement of said slide means in each direction when the lower one of said lenses is in the fiche projecting position thereof.

In a microfiche reader of the type having means for projecting an image projecting light beam onto an image viewing surface, that improvement which comprises:

• a horizontally supported turntable having a light projecting port through the center thereof, an X-Y fiche transport mounted on said turntable transversely of said light projecting port having a pair of transparent plates adapted to have a fiche sandwiched therebetween, means bridging said turntable and slidably supporting a pair of lenses of different power and including means for simultaneously shifting said lens crosswise of said X-Y transport while gradually lifting one lens and gradually lowering the other lens into contact with said X-Y transport and into alignment with said image projecting light beams, and means to hold said other lens firmly against movement relative to said image projecting light beams while said turntable and/or said X-Y transport are being adjusted to any position thereof.