Single step stepping motor control

Claim 1

In a control system for a stepping motor having a plurality of pairs of separate phase windings: bidirectional switch means comprising a pair of triggers each having ON and OFF outputs connected in a self-gating ring to provide a plurality of output conditions for generating a sequence of output levels in a predetermined relation; circuit means including a plurality of AND circuits connecting said ON and OFF outputs of said triggers to said pairs of windings, respectively, for energizing said windings in response to said levels in sequence to cause said motor to advance step by step; control means connected to said bidirectional switch means to apply a single signal of timed duration thereto in response to an input signal to advance said bidirectional switch means from one operating condition to another and produce a change in output level to cause the motor to commence a one step-forward function; and means including delay means comprising an inverter connected to invert said signal of timed duration and a single shot producing an output pulse having a predetermined duration in response to rise of said inverted input signal connecting said control means and said AND circuits operable to change the connections between said outputs of said bidirectional switch means and said windings to provide a one step-backward function for a predetermined time during said another operating condition of the bidirectional switch means in response to said signal of timed Duration, followed by a return to said one step-forward function.