随着我国工業的發展,要求起重設备的發展与其相适应。尤其58年大躍进以来,对重型超重設备更提出了迫切的任务。天津起重运输設备厂目前生产的50吨电动桥式起重机吊钩(圖1)是通过一个U形板与十字头相連接的,这种結構在冲击載荷下工作时能使釘孔硬化 With the development of our country’s industry, the development of lifting equipment is required to be compatible with it. In particular, since the Great Leap Forward of 58 years, urgent tasks have been put forth on heavy overweight equipment. At present, the 50-ton electric overhead traveling crane hook (Figure 1) produced by Tianjin Crane Transportation Equipment Factory is connected with the crosshead through a U-shaped plate. This structure can make the bolt hole harden when working under impact load