(1) Shackles should be smooth and flat, free from defects such as cracks, sharp edges, and overheating.
(2) Cast iron or cast steel shackles are strictly prohibited. Shackle bodies can be forged from killed steel, and pins can be forged from bar stock and then machined.
(3) Drilling or welding repairs are not permitted on shackles. Shackle bodies and pins that have undergone permanent deformation must not be repaired.
(4) During use, the shackle body and pins should be inspected; they must not be severely worn, deformed, or show fatigue cracks.
(5) During use, the lateral spacing must not be subjected to tensile force, and the pins must be securely fitted with safety pins.
(6) After proper pin assembly, the inner width of the shackle body must not be significantly reduced, and the threaded connection must be secure.
(7) The use of shackles must not exceed the specified safe load.
