I. The internal parts of the explosion -proof hand stracts the parts are damaged, resulting in changes in the force of the internal parts, resulting in the hard work of explosion -proof hand pour gourds.

Second, the chain shows a corrosive condition. The rust of the chain will increase the friction between the chain and the sprocket, which makes it difficult to pull it.

Third, the chain is distorted, so that the situation will form a card chain, causing the chain to pull.

Fourth, when the explosion -proof hand stretch the gourd overload, it will also make the hand pulling the gourd stretch.

V. Explosion -proof hand pulling gourds or water in a moist environment, which will make the explosion -proof hand pouring gourd parts sensitive, resulting in stretching.