Down the chain is pulled cited by human and sprocket drive to achieve small hand tools Lifting lifting operations , the main use for the next project and no field power environment . It can be the work of the group hanging below our weight lifting 40 tons an example to the actual analysis : lifting 40 tons of weight requires the use of four-point down the chain , there are a lot of customers believe that the use of four to 10 tonnes down chain group work carried hanging , in fact, this approach is very incorrect , why? Because the chain is inverted by the human operator lifting heavy objects , it is impossible to do four sets simultaneously rise or fall , so will the presence of some four different problems down the chain height . In addition , in case where a station down the chain to bear the weight causes beyond the chain broke , so since , in addition to three inverted chain will withstand the heavy weight of 40 tons , and down the chain or damage caused by the accident. Each chain bearing the correct way to pour all of 40 tons , so that once a station down the chain fails it will not affect the overall lifting work .