Attachment shackle with lockable rotating ferrule

An attachment shackle comprising:

• an open ring having threaded first and second end-parts arranged facing one another at opposite ends of the open ring, the first and second end parts defining a longitudinal space therebetween;
• a rotating ferrule fitted on the second end-part between a closed position and an open position to respectively close or open the space separating the two end-parts, said ferrule having a hollow tube with an inner threaded surface extending over a whole length of the ferrule:
• a spring;
• a lock housed in a recess of the ring at a rear of the threaded first end-part, the lock being biased to a locked position by the spring;
• and
• a notch located at a peripheral end of the ferrule so that the lock engages automatically said notch when the ferrule is in the closed position, unlocking being performed by a manual releasing action of the lock allowing the rotary ferrule to be unscrewed to the open position.