1. Field of the Invention
The present invention relates to an arrangement for the viewing projection of framed diapositives or slides particularly in which a plurality of slides are supported adjacent each other in the pockets of rigid strips.
2. Discussion of the Prior Art
An arrangement of the above-mentioned type is generally known from the present inventor's earlier U.S. Pat. No. 4,076,401, incorporated by reference herein.
In the known arrangement, a carriage which is adjustable in the direction of the longitudinal axis of a hollow prism supports a revolving head at each end thereof, whereas there is provided a stationary light source and lens. In order to shift from one row of slides to another, the hollow prism is rotated by a corresponding extent about its longitudinal axis. For effectuating a shifting from one slide to another with a row of slides, the carriage is displaced in the longitudinal direction of the hollow prism whereby one slide after another is located in the region intermediate the light source and the lens.
The accomodating of the framed slides in the pockets of rigid strips which are hingedly interconnected along their longitudinal sides, facilitates an extraordinarily satisfactory storage of the slides in which, through blocking of the articulation, there are formed images similar to album pages from a plurality of rigid strips, which are to be stored in a suitable container. On the other hand, the arrangement permits a sequential viewing projection of slides in an extremely comfortable manner, in which the spatial requirements of the arrangement are extraordinarily small. Thereby, each album page can be combined into a closed hollow prism and projected independently of the other album pages, or a plurality of album pages can be hinged to each other so as to presently form an open hollow prism for sequential viewing projection.
Notwithstanding these important advantages, actual practice has shown that the displacement of the hollow prism in the direction of its longitudinal axis through the intermediary of a carriage having two revolving heads signifies the need for a relatively high power input since a relatively large and heavy component must be conveyed over a relatively lengthy distance, and thereby only small tolerances are permissible in order to not adversely influence the sharpness of the picture representation.