Einrichtung zur Steuerung der Bewegung von Aufzeichnungskarten in einer Datenverarbeitungsanlage

A high precision high speed bidirectional step motor assembly, without gears or commutation, rapidly and precisely positions standard 80 column record cards without oscillation relative to a combined reading, punching and printing station of a card data recorder. Read cells and punch-print elements are separated by 2 units of card column displacement (2 x 0.087 inches). Four step drive excitation for the step motor (three drive pulses and one "hold" or "detent" pulse) is derived from pre-existing recorder circuits associated with buffer storage and logic sections. This permits reading, punching and printing operations to occur in synchronization with buffer and logic operations while card motion is definitely stopped in the holding stage of the motor drive cycle. A pressure roller which engages the card with a feed wheel extension of the step motor is disengaged either manually or by operation of conventional registration mechanisms as the cards are fed to the initial registration position of the combined station (card column "0" under punch and print elements; column 2 under read cells). In read mode the first dummy cycle of step motor excitation backs up the card one column returning column 1 of the card to the read position. The advantage of this is that the read cells can be utilized in a dual mode to detect the leading edges of cards as a condition of the registration operation and to read card apertures. In punching-printing mode the usual first "dummy" cycle of forward stepping is taken.