A seat belt buckle (12) includes a latch mechanism (20) and a field effect device (26). The latch mechanism (20) includes a latch (42) which is movable into and out of a locking position in which it engages a seat belt tongue (16) to interlock the tongue (16) with the latch mechanism (20). The field...http://www.google.de/patents/US5944135?utm_source=gb-gplus-sharePatent US5944135 - Seat belt buckle with field effect locking indicator and method of use
