Drive control for microfilm reader - has separate reel drives for fast wind and braking and third drive for slow scan

摘要

A drive control for a microfilm reader has separate motors on the two reels, for wind control in either direction, at fast speed, and with a third motor to provide a controlled slow scan speed. The film is braked rapidly by stopping the takeup motor and by reversing the supply reel motor at a limited torque. In this position the third drive inches the film at a controlled rate. The combined effect of the two main drive motors provides a rapid wind and a rapid brake, without any film jerking. The third drive motor is brought into contact with the film by a solenoid and acts against a pressure roller. The reader indexes the film rapidly and then allows a maximum control for the search. The motors are controlled by an electronic circuit.