Display device having a retentive memory

Claim 1

A DISPLAY DEVICE FOR PRESENTING A SELECTED ONE OF A PLURALITY OF VISUAL SYMBOLS COMPRISING, A RING OF MAGNETIC MATERIAL HAVING A SUBSTANTIALLY RECTANGULAR HYSTERESIS LOOP CHARACTERISTIC, AN ELECTRICAL WINDING ON SAID RING, A PLURALITY OF TERMINALS EACH CONNECTED TO SAID WINDING AT A RESPECTIVE DIFFERENT SPACED POSITION ON SAID WINDING, MEANS FOR ENERGIZING SAID WINDING THROUGH A SELECTED DIAMETRICALLY OPPOSED PAIR OF SAID TERMINALS FOR ESTABLISHING A RETENTIVE MAGNETIC FLUX IN A FIRST ANGULAR DIRECTION IN A SELECTED HALF PORTION OF SAID RING AND A RETENTIVE MAGNETIC FLUX IN THE OPPOSITE ANGULAR DIRECTION IN THE OTHER HALF PORTION OF SAID RING, MEANS COMPRISING A ROTATABLE MAGNETIC MEMBER POSITIONED WITHIN SAID RING AND ADAPTED TO ROTATE ABOUT THE AXIS OF SAID RING FOR PROVIDING A LOW RELUCTANCE PATH FOR SAID RETENTIVE MAGNETIC FLUX BETWEEN THE DIAMETRICALLY OPPOSED PORTIONS OF SAID RING ADJACENT TO THE POSITIONS WHERE SAID SELECTED PAIR OF TERMINALS ARE CONNECTED TO SAID WINDING, AND VISUAL DISPLAY MEANS RESPONSIVE TO THE ANGULAR POSITION OF THE SAID ROTATABLE MAGNETIC MEMBER, SAID VISUAL DISPLAY MEANS COMPRISING A DRUM CONCENTRICALLY POSITIONED AROUND SAID RING, SAID DRUM HAVING SYMBOLS TO BE DISPLAYED UPON ITS OUTER SURFACE, AND MEANS CONNECTING SAID DRUM TO SAID ROTATABLE MAGNETIC MEMBER.