Abstract: An ultrasonic nondestructive testing system and a contact-type, ultrasonic search unit for use in connection therewith are disclosed. The ultrasonic search unit includes a transducer crystal for receiving and transmitting ultrasonic energy, a housing in which the crystal is mounted, a dampening backing compound, and a wear-resistant cylindrical member or ring disposed within the housing and in which the crystal is mounted to provide a hard, durable, long-lasting contact face.

Abstract: An electrical connector having a breech lock is provided with a snap action or over-center spring such as a Belleville Washer. This is effective to positively bias all of the working parts of the connector into the fully mated or unmated positions. It is also effective to maintain the connector and the electrical contacts therein mated even though it may be subjected to large forces resulting from acceleration, vibration, etc., and to maintain all of the interfaces sealed even though the sealing materials may shrink, etc., from aging, etc.

Abstract: A parachute riser buckle is provided on the parachute harness for a quick release of the parachute risers from the harness. Blocking means on the buckle body has a latch position in which it blocks removal of the riser connecting portion and an unlatched position for permitting removal of the riser connecting portion. A latch preventing member is provided which has a position in which it prevents the blocking means from returning to its latched position from its unlatched position except when the riser connecting portion is inserted in the buckle body to prevent incorrect and non-positive latching of the blocking means with the riser connecting portion. A handle is provided to rotate with the blocking means and has a surface which prevents the latch preventing member from moving to its latch preventing position except when the handle moves the blocking member to its unlatched position.