桅杆(通称拔杆), 是起重机械当中构造简 单、拆装方便、起重量 较大、使用广泛的一种。 它的主要用途,是在机 械安装或建筑吊装工作 中,把设备件或建筑方 面的构件,起吊到设计 所要求的位置进行安装 固定。由于简单,许多单位可以自制。但是,对它的承受载荷不清楚,就容易出现问 Mast (commonly known as the pull rod), crane which is simple structure, easy disassembly, lifting a large, widely used. Its main use is in the mechanical installation or building hoisting work, the construction equipment or parts of the building, lifting the location required for the installation of the design and installation. Due to its simplicity, many units are self-made. However, its bearing load is not clear, it is easy to ask