Control apparatus with magnetoresistive pickoff means

Claim 1

CONTROL APPARATUS, COMPRISING: (A) A RIGID CYLINDRICAL HOUSING MEMBER WITH FIRST AND SECOND ENDS HAVING A LONGITUDINAL BORE THERETHROUGH, AND COMPRISING A FIRST MAGNETIC SECTION AT SAID FIRST END, A SECOND MAGNETIC SECTION AT SAID SECOND END, AND A THIRD MAGNETIZED SECTION MOUNTED BETWEEN SAID FIRST AND SECOND SECTIONS; SAID FIRST AND SECOND SECTIONS EACH COMPRISING A PAIR OF CYLINDRICAL PORTIONS HAVING A PLURALITY OF RAISED CIRCUMFERENTIAL FLANGES FORMED THEREON PERPENDICULAR TO SAID BORE AND EXTENDING INTO SAID BORE; (B) A FIRST CYLINDRICAL MAGNETORESISTIVE ELEMENT MOUNTED BETWEEN SAID PORTIONS OF SAID FIRST SECTION; A SECOND CYLINDRICAL MAGNETORESISTIVE ELEMENT MOUNTED BETWEEN SAID PORTIONS OF SAID SECOND SECTION; SAID MAGNETORESISTIVE ELEMENTS BEING CHARACTERIZED BY A CHANGE OF RESISTIVITY WITH A CHANGE OF MAGNETIC FLUX THERETHROUGH; (C) A CYLINDRICAL BEARING MEMBER MOUNTED WITHIN SAID BORE ON SAID THIRD SECTION; (D) AN ELONGATED ARMATURE MEMBER CONSTRUCTED FROM A MAGNETIC MATERIAL AND COMPRISING FIRST AND SECOND OPPOSING END PORTIONS AND A CENTRAL BEARING PORTION SEPARATING SAID END PORTIONS; SAID ARMATURE MEMBER BEING MOUNTED IN SAID BORE WITH SAID BEARING MEMBER SURROUNDING SAID BEARING PORTION TO PREVENT LATERAL MOVEMENT OF SAID ARMATURE MEMBER IN SAID BORE WHILE ALLOWING LONGITUDINAL MOVEMENT THEREIN; SAID FIRST AND SECOND END PORTIONS EACH HAVING A PLURALITY OF RAISED CIRCUMFERENTIAL FLANGES FORMED THEREON GENERALLY OPPOSITE SAID CORRESPONDING FLANGES ON SAID HOUSING MEMBER; SAID FLANGES ON SAID ARMATURE MEMBER HAVING AN OUTSIDE DIAMETER THAT IS SLIGHTLY SMALLER THAN THE INSIDE DIAMETER OF SAID FLANGES ON SAID HOUSING MEMBER WHEREBY FIRST AND SECOND VARIABLE AIR GAPS ARE PROVIDED BETWEEN SAID OPPOSITE FLANGES; SAID HOUSING MEMBER AND SAID ARMATURE MEMBER DEFINING A SERIES MAGNETIC CIRCUIT FROM ONE POLE OF SAID MAGNETIZED THIRD SECTION TO THE OTHER POLE THEREOF INCLUDING SAID FIRST SECTION, SAID FIRST AIR GAP, SAID FIRST END PORTION, AID BEARING PORTION, SAID SECOND END PORTION, SAID SECOND AIR GAP AND SAID SECOND SECTION; THE MAGNETIC FLUX IN SAID CIRCUIT THEREBY PASSING THROUGH SAID MAGNETRORESISTIVE ELEMENTS AND THROUGH SAID OPPOSITE FLANGES; THE LONGITUDINAL MOVEMENT OF SAID ARMATURE MEMBER IN SAID BORE CAUSING A CHANGE IN MAGNETIC RELUCTANCE BETWEEN SAID OPPOSITE FLANGES AS SAID FIRST AND SECOND AIR GAPS ARE CHANGED TO THEREBY CHANGE THE FLOW OF MAGNETIC FLUX THROUGH SAID MAGNETORESISTIVE ELEMENTS; AND (E) MEANS CONNECTED TO SAID MAGNETORESISTIVE ELEMENTS TO DETECT THE CHANGE IN RESISTANCE THEREOF AS AN INDICATION OF THE DEGREE OF MOVEMENT OF SAID ARMATURE MEMBER WITH RESPECT TO SAID HOUSING MEMBER.