PURPOSE: To prevent restriction on a driving range with the length of a closed magnetic circuit, by providing permanent magnets at the outside of a moving path for a magnetic detector.
CONSTITUTION: A potentiometer is composed of the following parts: a closed magnetic circuit 16 comprising counter parallel thin plates 11 and 12 made of magnetic material and permanent magnets 13 and 14, which are held between said facing plates; and a magnetic detector 15, which linearly moves between the counter plates and detects leaking magnetic flux between the counter plates. The permanent magnets 13 and 14 are provided at the outsides of the extending lines of a moving path for the magnetic detector 15. Namely, the closed magnetic circuit 16 comprises a pair of the facing U-shaped thin plates 11 and 12 and the permanent magnets 13 and 14, which are held with end parts 11b, 11c, 12b and 12c, which are made to extend from the side surfaces of the thin plates 11 and 12. The gap between the central parts 11a and 12a of the thin plates 11 and 12 is the moving path of the magnetic detector 15. Therefore, the moving range of the magnetic detector 15 is not restricted. The magnetic detector 15 can be attached to a material to be measured, which moves in a range broader than the measuring range.
SHIMIZU SHINKICHI
KURASHIMA SHIGEMI
