Frame location system
AssigneeRagen Precision Industries, Inc.
InventorHans Weigert
Life of this patent
Estimating the term…
Abstract
Frame location system for microfilm retrieval system. Frame address of desired frame is stored in first reversible counter having maximum count greater than the maximum possible number of frames in a roll of microfilm. Frame address of frame currently being viewed is stored in second reversible counter of same count capacity. A burst of pulses equal to capacity of both counters causes both to count up. First counter to overflow gates burst pulses into third reversible counter. Second counter to overflow terminates count in third counter. As microfilm moves, optical sensors sense frame identifying "blips" on microfilm thereby reducing count in third counter and slowing film to halt when desired frame is in position at viewing station.
Claims10
A frame location system for use with a strip record medium retrieval device of the type that includes means for moving the strip record medium past a predetermined station, said strip record medium containing m frames, each frame having a unique address, which comprises:
- a first reversible counter having a counting capacity of m pulses for storing the address of a selected frame to be moved to said predetermined station and generating an overflow signal when the accumulative count applied thereto exceeds m;
- a second reversible counter having a counting capacity of m pulses for storing the address of the frame presently at said predetermined station and generating an overflow signal when the accumulative count applied thereto exceeds m;
- a third reversible counter, having a counting capacity of m pulses connected to said first and second reversible counter, for determining the difference between the addresses stored therein;
- means responsive to the application of a start search command from an external source, for generating a burst of m pulses;
- means for connecting the output of said pulse generating means to the up-count inputs of said first and second reversible counters to cause said counters to overflow;
- logic means, connected to said first and second reversible counters, for routing pulses from said burst of pulses to the up-count input of said third reversible counter upon receipt of a first overflow signal from either said first or said second reversible counter and for terminating the same upon receipt of a second overflow signal from either said second or said first reversible counter;
- and
- means, responsive to said address difference, for actuating said strip record moving means, whereby said selected frame is presented at said predetermined station.
Dependencies are inferred from the claim text.