Electrical apparatus for providing an indication of the relative positions of relatively movable means

Claim 1

POSITION-ENCODING APPARATUS COMPRISING: A FERROMAGNETIC STATOR HAVING A MAIN BODY PORTION AND A SERIES OF TEETH EXTENDING FROM THE MAIN BODY PORTION; A PLURALITY OF FIRST ELECTRICAL WINDINGS EACH OF WHICH EMBRACES SUCCESSIVE GROUPS OF SAID TEETH IN OPPOSITE SENSES IN A PREDETERMINED PATTERN, EACH OF WHICH IS FIXEDLY MOUNTED WITH RESPECT TO THE TEETH OF SAID GROUP AND EACH OF WHICH IS ELECTROMAGNETICALLY COUPLED TO EACH OF THE TEETH OF SUCH GROUP, THE GROUPING OF THE TEETH BY THE DIFFERENT FIRST WINDINGS BEING DIFFERENT; A SECOND ELECTRICAL WINDING ON SAID STATOR FIXEDLY MOUNTED WITH RESPECT TO SAID TEETH AND ELECTROMAGNETICALLY COUPLED TO ALL OF SAID TEETH IN THE SAME SENSE THEREBY TO HAVE DIFFERENT PORTIONS THEREOF INDUCTIVELY COUPLED TO SAID FIRST WINDINGS BY THE DIFFERENT TEETH; AND A U-SHAPED FERROMAGNETIC YOKE WHICH IS MOUNTED FOR MOVEMENT SELECTIVELY TO ANY SAID TOOTH, AND WHICH INCLUDED A FIRST PORTION LYING IN CLOSE PROXIMITY TO THE SELECTED ONE OF SAID TEETH AND A SECOND PORTION EXTENDING FROM SAID FIRST PORTION INTO CORRESPONDINGLY CLOSE PROXIMITY WITH SAID MAIN BODY PORTION OF THE STATOR SO THAT SAID YOKE WITH SAID MAIN BODY PORTION AND WITH THE SELECTED TOOTH FORMS A SUBSTANTIALLY CLOSED FERROMAGNETIC CIRCUIT ENHANCING THE INDUCTIVE COUPLING BETWEEN THE FIRST AND SECOND WINDINGS AT SAID TOOTH, SAID ELECTRICAL WINDINGS HAVING TERMINAL MEANS TO PROVIDE DIGITAL CONVERSION OF THE POSITION OF SAID YOKE.