一、掩护支架的研制和应用条件 西德于1970年首次应用了掩护支架。试验初期,采用的是《马列里格德罗》公司生产的底座与托梁呈单铰点连接的掩护支架。在此之前,仅有40％的商品煤是从装备机械化支架的回采工作面采出的,其余部分则从用单体金属支柱或木支柱装备的工作面采 First, cover the development and application of shielding conditions West Germany in 1970 for the first time the use of shielding bracket. At the beginning of the test, the shield bracket with the single hinge point connected with the base and the joist manufactured by “Mali Rigidro” Company was used. Prior to this, only 40% of commercial coal was taken from the mining face equipped with mechanized supports and the rest from the faces equipped with either monolithic or wooden struts