Endless loop cassette
OwnerFred C. Ponceinventor
Life of this patent
Estimating the term…
Abstract
Improved endless loop film cassettes which allow film to be unwound and rewound about a common reel by removal of the innermost convolution of film from the center of the film pack without scrubbing and returning the same to the outermost convolution of the film pack. Two embodiments are disclosed, both capable of operation at any angle between horizontal and vertical.
Claims12
In a cassette for an endless loop, wound pack of film, said film being planar with a width dimension at least 10 times its thickness dimension and a length dimension at least 100 times its width dimension, wherein the innermost convolution of film is withdrawn from the center of the film pack, which is rotating in a primary path, traversed through a secondary path, led to a first position outside said primary path, and then fed back to a second position outside said primary path, then onto the periphery of the film pack as the outermost convolution thereof;
- the improvement, comprising:
- a plurality of film pack rollers fixed in position along said primary path and adapted to support at least a portion of the inner circumference of the film pack, said film pack rollers being disposed to approximate at least an arc of a circle having a first radius;
- a plurality of film path rollers adapted to guide the innermost convolution of film from said film pack along said secondary path, said film path rollers being fixed in position to approximate at least an arc of a circle having a second radius less than said first radius and being disposed for spiral concentricity with said film pack rollers;
- and
- differential take-up means, for adjusting film tension, in the path of said film at at least one of said first and second positions.
The method of removing a convolution of film from an endless loop wound film pack and returning it thereto, comprising the steps of:
- supporting at least a portion of the inner circumference of said film pack at a first fixed radius;
- withdrawing the innermost convolution of film from the center of the film pack;
- engaging said innermost convolution of film with a plurality of rollers fixed to approximate an arc in spiral concentricity with said film pack;
- guiding said innermost convolution of film from the plane of the film pack to a plane parallel and spaced therefrom past a first position outside said film pack and then past a second position outside said film pack back to the plane of the film pack, the film returning to the plane of the film pack forming the outermost convolution of the film pack;
- and
- adjusting tension on said film at at least one of said first and second positions.
Dependencies are inferred from the claim text.