Patent ID: 7671596

Claim:
A detector for locating metallic objects, comprising: a transmit coil ( 116 , 216 ) and at least two receive coils ( 112 , 114 ; 212 , 214 ) that are inductively coupled to one another, wherein the at least two receive coils ( 112 , 114 ; 212 , 214 ) are located coaxial to one another in a first plane ( 126 , 226 ), and the transmit coil ( 116 , 216 ) is located in a second, parallel plane with a height offset relative to said first plane, at least two compensating windings ( 130 , 132 ; 230 , 232 ) located coaxially to the transmit coil and the receive coils are formed so that one of the two compensating windings is axially offset from the transmit coil for compensating mis-positioning of the transmit coil.