Position transducers

Claim 1

A POSITION TRANSDUCER COMPRISING (A) A CLOSED MAGNETIC CIRCUIT DEFINED BY A STRUCTURE COMPRISED OF HIGH MAGNETIC PERMEABILITY MATERIAL, (B) A LATERAL MAGNETIC CIRCUIT MEANS EXTENDING FROM SAID CLOSED CIRCUIT OF A FIRST PORTION THEREOF, (C) FIRST AND SECOND COILS COUPLED TO SAID CLOSED CIRCUIT, ONE ON EACH SIDE OF SAID FIRST PORTION, WHEREBY THE ENTIRE LATERAL. MAGNETIC CIRCUIT MEANS ALONG SAID CLOSED CIRCUIT IS BETWEEN THE ENDS OF SAID COILS ENCLOSING SAID FIRST PORTION, (D) A COIL COUPLED TO SAID LATERAL CIRCUIT MEANS, (E) A SECOND PORTION OF SAID CLOSED CIRCUIT BETWEEN SAID FIRST AND SECOND COILS AND OPPOSITE SAID FIRST PORTION, (F) SAID SECOND PORTION HAVING A HIGH PERMEABILITY AND HAVING A RELUCTANCE ALONG ITS LENGTH WHICH IS A PREDETERMINED FUNCTION OF DISTANCE THREALONG, (G) LOW MAGNETIC RELUCTANCE MEANS BRIDGING BETWEEN SAID LATERAL CIRCUIT MEANS AND SAID SECOND PORTION, THEREBY TO FORM FIRST AND SECOND FLUX PATHS IN SAID CLOSED MAGNETIC CIRCUIT AND BETWEEN SAID BRIDGING MEANS AND SAID LATERAL CIRCUIT MEANS, A FIRST ONE OF SAID PATHS BEING COUPLED TO SAID FIRST COIL AND THE SECOND PATH BEING COUPLED TO SAID SECOND COIL, (H) A FIRST END OF SAID MAGNETIC BRIDGING MEANS ADJACENT SAID SECOND PORTION BEING MOVABLE RELATIVE THERETO, THEREBY TO VARY THE RELATIVE RELUCTANCE OF SAID FIRST PATH WITH RESPECT TO THAT OF SAID SECOND PATH, SAID VARIATION IN RELUCTANCE BEING DUE SUBSTANTIALLY SOLELY TO A CHANGE IN THE RELATIVE RELUCTANCES OF THE PARTS OF THE HIGH PERMEABILITY PARTS OF SAID STRUCTURE IN THE RESPECTIVE PATHS.