The jointless sliding contact wire and the middle jointless sliding contact wire are a kind of sliding contact wire that will never power off. Use oxygen-free copper (conductivity up to 99.99%) to transmit power, and the thickness of copper conductor (general standard thickness is 2.8m/m × 10W), low voltage drop, good conductivity; A safety electric rail with the same length can be matched according to the length of the user's workshop or the user's needs, so that there is no interface in the safety distribution of the whole workshop, which really solves the problem of short circuit or non-operation of the domestic sliding wire due to the frequent jamming of the collector brush due to the interface. It is also applicable to the design of curve, arc and high and low walking. Thus, the whole crown block project is beautiful, clean and safe. In the ranks of automatic production, it is the choice of power supply system.