Roller chains are generally connected by a number of chain links into a ring or fixed end use, regardless of which need to connect the chain links. Moreover, when the roller chain is an odd number of chain links, although the transition link can be used, because it may lead to a reduction in transmission capacity and maximum allowable tension, please design an even number of chain links as far as possible. In addition, under normal circumstances, only anti-rust oil is applied on the connecting chain and the transition chain. When assembling on the body, apply enough lubricating oil to the pin and sleeve.