手扳葫芦在施工现场经常用来作装卸、安装小型设备、小型构件和管道等的工具。手扳葫芦的工作原理是由两对平滑自锁的夹钳，象两只钢爪一样交替夹钢丝绳，作直线往复运动，从而达到牵引作业。它能在各种工程中担任牵引、卷扬。起重等作业。除能在水平、垂直方向使用外，它还能在斜坡、高低不平、狭窄的巷道、曲折转弯的工作条件下进行操作，也可以在任何地方及无电源的环境中使用。

Lever blocks in the construction site often used as a loading and unloading, installation of small equipment tools, small components and pipes, etc. Working principle of lever hoist is made up of two smooth self-locking clamp, like two steel claw clip wire rope alternately, as a straight line reciprocating movement, so as to achieve traction. It can be in various engineering as traction, winding. Lifting operations, etc. Besides can be used in horizontal and vertical direction, it also can be in slope, rugged, narrow roadway, twists and turns under the working conditions of the operation, also can be in any place and without the power of the environment.