MAGNETIC NON-CONTACT THICKNESS GAUGE WITH MEANS TO COMPENSATE THE EFFECTS OF STRAY FIELDS ON THE GAUGE

摘要

A thickness measuring device wherein means are positioned at opposite sides of and in selected spacing relative to a work piece being measured and respectively include magnet responsive means supported by one positioning means and a magnet supported by the other positioning means, said magnet and magnet responsive means defining a flux circuit intercepted by said work piece. The magnet responsive means include spaced parts and a third relatively small part between said spaced parts at which flux in said circuit is concentrated. A flux sensitive resistor is positioned to respond to flux variations at said third part and is connected in a Wheatstone bridge meaSuring circuit which indicates variations in the thickness of the work piece.