在高山和河谷等特殊地形条件下进行架空输电线路张力放线时，采用常规的地面展放导引绳的架线工艺比较困难，此时采用直升机放线工艺是可行的，而且经济性可能更好。根据直升机放线工艺的需要，研制了直升机放线滑车，该直升机放线滑车的创新技术包括导引绳引导臂、偏心转动门、导引绳对中活门和防滑车摆动梁的设计等。

In tension stringing of overhead transmission line, stringing by helicopter will be feasible and much less expensive rather than traditional ways for some special terrain with high mountain and valley. Therefore, the helicopter tackle for tension stringing is developed, of which the innovative technologies include the design of leading string guide arm, eccentric rotary gate, centring valve, walking beam of anti-skidding truck and etc.