没有统一的安全监督法规美国是世界上最早使用电动起重机的国家之一。从1883年美国起重机制造商Franklin生产出一系列小起重量,动力驱动的起重设备开始,各起重机制造商纷纷制造了大量的起重机械,广泛用于制造业中。20世纪初,随着 There is no uniform safety supervision regulations The United States is one of the first countries in the world to use electric cranes. From the beginning of a series of small lift, powered lifting gear produced by the U.S. crane manufacturer Franklin in 1883, crane manufacturers have manufactured a large number of cranes and are widely used in the manufacturing industry. Early 20th century, with