A transducer for measuring the displacement of an electrically conductive objective

Claim 2

A transducer for measuring the displacement of an electrically conductive object which comprises an uncharged sensing element formed of a conductive material and having a front surface shaped so that it can be positioned parallel to a surface of said electrically conductive object; a shield element formed of a conductive material and shaped so as to at least partially surround said sensing element, said sensing and shield elements being printed on a board of non-conductive material with said sensing element being circular in form and said shield element being arcuate in sHape and spaced apart from said sensing element; a conductor positioned on said board between said sensing element and said shield element; an electrical lead connected between said conductor and ground; and a source of constant direct current voltage connected to said shield element.

Claim 3

A transducer for measuring the displacement of an electrically conductive object which comprises an uncharged sensing element formed of a conductive material and having a front surface shaped so that it can be positioned parallel to a surface of said electrically conductive object; a shield element formed of a conductive material and shaped so as to at least partially surround said sensing element, said sensing and shield elements being printed on a board of non-conductive material with said sensing element being circular in form and said shield element being arcuate in sHape and spaced apart from said sensing element; a conductor positioned on said board between said sensing element and said shield element; an electrical lead connected between said conductor and ground; and a source of constant direct current voltage connected to said shield element.

Claim 4

A transducer for measuring the displacement of an electrically conductive object which comprises an uncharged sensing element formed of a conductive material and having a front surface shaped so that it can be positioned parallel to a surface of said electrically conductive object; a shield element formed of a conductive material and shaped so as to at least partially surround said sensing element, said sensing and shield elements being printed on a board of non-conductive material with said sensing element being circular in form and said shield element being arcuate in sHape and spaced apart from said sensing element; a conductor positioned on said board between said sensing element and said shield element; an electrical lead connected between said conductor and ground; and a source of constant direct current voltage connected to said shield element.

Claim 5

A transducer for measuring the displacement of an electrically conductive object which comprises an elongated metal body member having a longitudinal opening formed therein and extending throughout its length; a first metal plate having a flat front surface, said plate being attached to one end of said body member; an insulating material disposed between said body member and said first metal plate; an opening formed in said first metal plate in alignment with said longitudinal opening formed in said body member; a second metal plate having a flat front surface, said second metal plate being positioned in and spaced apart from said opening formed in said first metal plate, and said flat surface of said second metal plate being in the same geometric plane as said flat surface of said first metal plate; a hollow insulator fixedly positioned in said opening in said body member, the end of said insulator adjacent said second plate member being closed with the opposite end of said insulator being open; a metal tube disposed in an opening in said closed end of said insulator, one end of said tube being attached to said second metal plate; a coaxial cable having a central conductor and an outer shield, one end of said cable being positioned in said insulator with its central conductor connected to said metal tube; a lead connecting said shield of said coaxial cable to said body; and a source of constant direct current voltage connected to said first metal plate.

Claim 6

A transducer for measuring the displacement of an electrically conductive object which comprises an elongated metal body member having a longitudinal opening formed therein and extending throughout its length; a first metal plate having a flat front surface, said plate being attached to one end of said body member; an insulating material disposed between said body member and said first metal plate; an opening formed in said first metal plate in alignment with said longitudinal opening formed in said body member; a second metal plate having a flat front surface, said second metal plate being positioned in and spaced apart from said opening formed in said first metal plate, and said flat surface of said second metal plate being in the same geometric plane as said flat surface of said first metal plate; a hollow insulator fixedly positioned in said opening in said body member, the end of said insulator adjacent said second plate member being closed with the opposite end of said insulator being open; a metal tube disposed in an opening in said closed end of said insulator, one end of said tube being attached to said second metal plate; a coaxial cable having a central conductor and an outer shield, one end of said cable being positioned in said insulator with its central conductor connected to said metal tube; a lead connecting said shield of said coaxial cable to said body; and a source of constant direct current voltage connected to said first metal plate.