云梯用于攀越城墙攻城的用具,梯下带有车轮,可以推动行驶,配备有防盾、绞车、抓钩等器具,有的带有用滑轮升降设备。云梯的发明者是春秋时期的鲁班,是战国之后攻城的必备工具,唐代和宋代对云梯结构进行了大幅改进。投石车投石车是利用杠杆原理 The ladders are used to climb over walls and siege gear. The ladders are equipped with wheels to propel the vehicle. Equipped with anti-shield, winch and grappling hooks, some are equipped with pulley lifters. The inventor of the ladder was the Luban during the Spring and Autumn Period, which was an indispensable tool to siege the city after the Warring States Period. The structure of the ladder was greatly improved in the Tang and Song dynasties. Catapult stone catapult is the use of leverage