ulley blocks;Safety;Sprocket assemblies;Testing【摘要】: B30.21 includes provisions which apply to the construction, installation, operation, inspection, and maintenance of ratchet and pawl and friction brake type manually lever operated chain, wire rope, and web strap hoists used for lifting, pulling, and tensioning applications.【中国标准分类号】: J80【国际标准分类号】: 53_020_99【页数】: 【正文语种】: 英语 | 欢迎光临 世界资料网论坛 (http://bbs.infoeach.com/) | Powered by Discuz! X2.5 |