Galvano-magnetro effect apparatus

Claim 1

A galvano-magnetro effect apparatus comprising: a. a base plate provided with a through hole, b. a magnetic upper yoke attached to the underside of said base plate, c. a lower yoke which is arranged opposing to said upper yoke through a space, d. a rotating shaft which is inserted into the through hole of said base plate so that its main part contacts said upper yoke and its lower end is positioned close to said lower yoke, e. a projected end which is provided at the lower end of said rotating shaft so that is eccentrically moves in reference to the axis of the rotating shaft when the rotating shaft rotates, f. at least one magnet which is positioned between said upper yoke and lower yoke, g. a magnetro-resistance effect device which is provided at the lower yoke surface so that it is opposed to the lower end of said rotating shaft, and h. a pushing means which pushes the device position of said lower yoke from the lower side, wherein said rotating shaft has the part, below the position where it contacts said upper yoke, being made of a magnetic material so that said part is combined with upper yoke, lower yoke and magnet to form the closed magnetic path, said magnet is so arranged that one magnetic pole contacts the upper yoke and the other magnetic pole contacts the lower yoke and the magnetic flux can be concentrated into the gap formed between the projected end of the rotating shaft and the device, saiD device is provided with at least two terminals and is designed so that the area of the magnetism sensing surface between the terminals opposing to the projected end varies with eccentric movement of the projected end and said pushing means is devised so that the pushing force applied to the lower yoke is changed by pushing the device fixing part of said lower yoke toward the projected end.