Sequential control circuit capable of sequencing through a number of stable states in a predetermined order

A sequential control circuit capable of sequencing through a number of stable states in a predetermined order, starting from a predetermined stable state and sequencing in either of two opposite directions, said circuit comprising a contact maker normally assuming a first position and capable alternatively of assuming either of two transient positions of contact, said contact maker when in one of the transient positions generating a transient signal indicative of the particular transient position assumed;

• timing means coupled to said contact maker for providing a timer signal in response to generation of a transient signal by said contact maker;
• and a logic circuit coupled to said contact maker and to said timing means and capable of sequencing through a number of output conditions corresponding with the stable states, said logic circuit, during presence of the timer signal, being responsive to a transient signal to sequence to another output condition, the direction of sequencing of said logic circuit being dependent upon the transient position assumed by said contact maker, said logic circuit including means responsive to initial application of voltage to said logic circuit for setting said logic circuit to a predetermined one of the output conditions.