Concept: Safety hook (carabiner), also called "main lock", is the most commonly used connection tool for connecting ropes, webbings, anchor points, equipment, etc. Safety shackles must have a locking function. The locking function is divided into two categories: manual locking and automatic locking. The hand turn lock is suitable for use in most environments, but it must be locked immediately after connection, otherwise an accident may occur due to inadvertent equipment collision causing the lock door to open during operation. The unlocked shackle is just like the gate in the open state, and its pulling force (breaking load) is much lower than the locked state. There are two types: ordinary type (rotating type) and spring hook (self-locking type). There are many shapes such as "D" (rescue, military) and "8" shape (engineering, construction).
structure type:
(1) "8" shaped safety hook. The opening and closing mechanism is a spring tongue automatic return type, and the lock arm is equipped with a self-locking latch composed of a safety pin, a compression spring and a wrench. When opening the hook, lift the wrench with your fingers to disengage the safety pin, and press the lock arm downward to open the lock arm. If the lock arm is released, the lock arm will automatically reset under the elastic force of the return spring. While the self-locking latch closes the hook mouth through the outward elastic force of the opening and closing mechanism, the compression spring will tighten the safety pin and lock the lock arm. .
(2) The "D"-shaped safety hook is composed of two parts: the hook body and the lock arm. The opening and closing mechanism is a spring tongue automatic return type. The lock arm part has two safety structure designs: torsion self-locking and threaded hand lock. The self-locking structure lock The arm is equipped with a rotating compression spring, and the arm lock sleeve can automatically reset and lock. There are threads on the lock arm of the hand lock structure. The rotating lock arm sleeve can open and lock the safety hook.
Material: The material of the safety hook is usually made of stainless steel, alloy steel or aluminum alloy. Steel safety hooks are harder and heavier and are suitable for connecting anchor points or coming into contact with sharp metal equipment, such as safety slings and descenders. The breaking load of aluminum alloy hooks is not inferior to that of steel products. Aluminum safety hooks are relatively light in weight and are suitable for connecting various personal protective equipment and carrying multiple spares with you. However, aluminum alloy is less resistant to cutting, so avoid hooking it with other sharp metals when using it.
Inspection and maintenance: The shape of the safety hook should be checked frequently. If there is deformation or cuts, it should be discarded immediately and no longer used. If there is sand or iron filings intruding into the lock teeth, it should be cleaned immediately. Alloy steel safety hooks should be maintained with anti-rust agents and stored in special containers after use. If the safety hook accidentally falls from a height (more than 2m) to a hard ground, even if its appearance is not damaged, its internal alloy components may be seriously damaged and should be discarded and avoided from being used again.