Koda and Androlia
Apparatus for non-destructively detecting a nugget for spot welding
 An apparatus for detecting a nugget for spot welding utilizing the magnetic after-effect which is generated when a variation in the magnetic field is applied to a nugget. The apparatus includes a driving coil, which applies a magnetic field variation to a spot-welded nugget, and a magnetism sensing element, which detects variations in magnetic flux density arising in the vicinity of the nugget as a result of the magnetic field variation. The magnetism sensing elements may be installed in an array form so as to face the nugget and the area around the nugget. 
Kyokutoh Co., Ltd.
G G
G01N G01N
inventional inventional
Takashi Kaneyasu
Kimura Arakawa