A lock mechanism for releasably securing a pivot door of a thrust reverser includes a frame, a blade housing connected to the frame, a blade member slidably disposed within the blade housing and configured to engage a lock fitting of the pivot door, an actuator configured to translate the blade member in a first direction with respect to the frame; a spring element configured to translate the blade member in a second direction with respect to the frame, and a loose-joint coupling configured to connect the actuator to the blade member.