US Patent 7770649 Locking device

A locking device for locking an exchangeable unit in an insertion opening of an associated housing, particular in maritime mineral oil or mineral gas extraction, comprises locking elements adjustable between an insertion opening and a locking position, wherein in its insertion direction the unit can be inserted into the insertion opening, and is locked in the locking position within the insertion opening and relative to the housing. The locking elements are formed as thread segments spaced apart by insertion gaps in the circumferential direction and arranged on the outer side of the unit and being aligned with the insertion opening, said thread segments being arranged in the insertion opening at a gap and being in thread engagement in the locking position.