This machine is called Bridge Gantry Crane. 这种机器叫路桥门式起重机。
It provides a theoretical basis for super-low headroom large tonnage overhead traveling crane development. 为柔性化设计理念提供了有力的支持，同时为超低净空大吨位桥式起重机的成功研制奠定了理论基础。
If the site is small, it may be commanded by a gantry crane. 假如场地小，则可采用龙门式吊车进行操作。
One difficulty in every building for heavy industry is the arrangement of the supports for an overhead crane. 重工业的所有厂房均存在一个困难问题，即如何布置桥式吊车的支承结构。
