Detenting apparatus for electromagnetic indicator wheel structure

Claim 1

IN A SYMBOL DISPLAY DEVICE OF THE TYPE UTILIZING: (1) A PANEL HAVING A WINDOW; (2) A STATOR FOR SELECTIVELY EXTABLISHING ANY ONE OF A PLURALITY OF DISCRETELY ORIENTED MAGNETIC FIELDS, THE STATOR HAVING AN ANNULAR FERROMAGNETIC CORE; AND (3) A ROTOR HAVING A PERMANENT MAGNETIC ATTACHED TO A DRUM, THE DRUM HAVING A PLURALITY OF SYMBOLS MARKED UPON ITS PERIPHERY, THE DRUM BEING SITUATED TO PRESENT ITS SYMBOLS IN THE WINDOW OF THE PANEL, THE MAGNET BEING ENCIRCLED BY THE STATOR''S CORE AND THE STATOR''S CORE BEING ENCIRCLED BY THE DRUM, THE ROTOR BEING MOUNTED TO PERMIT THE MAGNET TO ROTATE INTO ALIGNMENT WITH THE DISCRETELY ORIENTED MAGNETIC FIELD ESTABLISHING BY THE STATOR; THE IMPROVEMENT COMPRISING (A) A PLURALITY OF MAGNETIZABLE DETENT ELEMENTS ARRANGED IN A CIRCULAR ARRAY SURROUNDING THE ANNULAR FERROMAGNETIC CORE OF THE STATOR, AND (B) A REGISTER MAGNET AFFIXED TO THE DRUM AND POSITIONED TO TRAVEL IN A CIRCULAR PATH OUTSIDE THE ANNULAR CORE AND CLOSE TO THE CIRCULAR ARRAY OF DETENT ELEMENTS, THE REGISTER MAGNET BEING ATTRACTED BY THE ADJACENT MAGNETIZED DETENT ELEMENT TO STATION WHERE A SYMBOL IS REGISTERED IN THE WINDOW OF THE PANEL.