A lock assembly having a housing containing a push rod movable along its longitudinal axis between a locked position where the push rod is extended outwardly of the housing and a retracted, unlocked position. A movable latch moves radially to engage with the push rod to hold it in the locked position and to disengage from the push rod to allow the push rod to move to its unlocked position. The latch member has an opening that, when aligned with the main axis of the push rod, allows the push rod to pass through the opening but when the latch member is offset with respect to that axis the latch member abuts against the push rod to prevent the push rod from moving to its unlocked position. A pushbutton moves the latch member and a locking assembly blocks the movement of the pushbutton when the lock assembly is locked.