目前我国使用的塔机种类繁多,性能各异。按其变幅形式划分,可分为水平小车变幅和动臂变幅两种。前者通过变幅小车的水平移动,实现变幅。在变幅过程中,载荷始终保持水平移动,即可实现带载变幅,不需要幅度指示器;后者则是通过改变臂架仰角的大小,而达到改变幅度的目的。在变幅过程中,吊钩的离地高度是变化的。基于安全原因,动臂式塔机不能带载变幅,而只能空载变幅。为了做到调整时心中有数,就需要有度量标志,即幅度指示器。因此,幅度指 At present, there are many kinds of tower cranes in use in China, and their performance varies. Divided according to the amplitude of its form, can be divided into two kinds of horizontal trolley amplitude and boom amplitude. The former achieves amplitude change through the horizontal movement of the trolley. In the process of amplitude change, the load always maintains a horizontal movement, which can realize the amplitude variation with load, and does not require the amplitude indicator; the latter achieves the purpose of changing the amplitude by changing the elevation angle of the boom. During the luffing process, the height of the hook from the ground changes. For safety reasons, boom-type tower cranes cannot be loaded with variable amplitude, but can only be unloaded. In order to make adjustments, you need to have metrics, which are amplitude indicators. Therefore, the amplitude refers to