A magnetic detector instrument includes an elongate circuit board and a magnetic sensor assembly which slides into a slot in one end of the board with edge portions of the board defining the slot being received in opposed elongate grooves formed in the sensor assembly. Also, a fitting for retaining the...http://www.google.com.hk/patents/US4536710?utm_source=gb-gplus-share專利 US4536710 - Magnetic detector instrument with board-mounted sensor assembly
