Inductive proximity sensor and position transducer with a passive scale

An inductive proximity sensor comprising:

• an inductive circuit including a single length of sensor wire forming a sensor area containing non-magnetic cores, and a supply circuit means for generating a magnetic field near and around said sensor wire in said sensor area, said magnetic field extending a sensor distance from said sensor wire, said sensor distance being approximately two or three times a cross section distance of said sensor wire, said supply circuit means also having a step-down transformer with a high ratio between a primary and a secondary winding, said step-down transformer being interposed between a power supply and said sensor wire;
• and
• detection means electrically connected to said inductive circuit and for monitoring said magnetic field of said sensor wire and detecting an alteration in said magnetic field due to electrically conductive material intercepting magnetic flux lines within said sensor distance.

A measurement transducer comprising:

• a cursor having a single length of sensor wire formed into a substantially straight member in a sensor area, a supply circuit means for generating a magnetic field near and around said sensor wire, said supply circuit being electrically connected to said sensor wire, and said cursor also having detection means for monitoring said magnetic field and detecting an alteration in said magnetic field due to electrically conductive material intercepting magnetic flux lines of said magnetic field;
• and
• a scale having a plurality of passive transversal short circuit means for forming an electrical short circuit to intercept and alter said magnetic field, said short circuit means being aligned in a substantially straight formation and spaced at substantially constant steps, an amount of flux of said magnetic field intercepted by said scale being cyclically variable as a function of relative position between said cursor and said scale, said scale being formed as an engraved metallic mass with parallel and equidistant bar projections as said short circuit means.