Safe use of hooks and shackles during construction
1. The C-type hook is a spreader that hooks heavy objects from the lifting device. The hook has two types: single hook and
double hook. When the hook weight is below 80t, the single hook type is commonly used, and the double hook is used for
large crane devices of 80t or more.
(1) Scrap criteria for hooks: The hooks should be inspected frequently. If one of the following conditions is found, it must be scrapped and replaced:
1.When there are cracks and breaks on the surface; the opening degree is increased by 15% compared with the original size;
2.The dangerous section and the hook neck have permanent deformation, and the torsional deformation exceeds 10 degrees;
3.The lanyard section wears more than 10% of the original height;
4.The dangerous section and the hook part are plastically deformed.
(2) Precautions for use of C-type hooks:
1.The hook of the crane is strictly forbidden to repair welding, mainly because the high temperature generated by welding will cause structural changes in the material and changes in mechanical physical properties, and increase the brittleness of the material.
2.In the lifting and hoisting work, in order to prevent the hook from being unhooked, the hook should be equipped with a safety device to prevent unhooking.
When the 3C type hook is replaced, the new hook shall have the certificate of the manufacturing unit and other technical certification documents before it can be put into use.
2. The shackle is used for the connection between the rope buckle (such as steel wire rope) and the rope buckle, the rope
buckle and the component lifting ring. It is a widely used connecting tool in lifting and hoisting operations.
(2) Precautions for shackle use：
1.When lifting large objects such as large formwork, concrete buckets and prefabricated panels, shackles must be used;
2.shall not exceed the allowable load capacity of the snap ring;
3.The shackle must be forged, usually made by forging heat treatment of No. 20 steel, and it is forbidden to use the
shackle for casting and welding repair;
4.The shackle pin and the bottom of the ring should be used (ie, the force is applied in the height direction). It is strictly
forbidden to lift the wire rope on both sides of the shackle. That is, the shackle cannot be laterally stressed, and the lateral
use of the shackle may cause deformation of the bending ring. Especially when the shackle is used, the deformation of the
bending ring may cause the pin to be disengaged from the pin hole, thereby causing the hanging object to fall off and
causing a safety accident;
5.The shackle and pin should be checked frequently during use. If serious wear, deformation or fatigue cracks are
found, they should be replaced in time;
6.When lifting heavy objects, bolt-type shackles must be used to improve safety and safety factor.
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