天津市第三炼钢厂用龙门吊钩吊运钢水包,因缺乏安全装置,曾发生脱钩事故。为此,厂里组成“三结合”小组,试验成功在龙门吊钩上接装安全链(见附图),防止了脱钩事故的发生。起初,在天车钩的钩脖上加一卡箍,卡箍两侧分别焊上索链环和索链挂钩,天车钩挂上龙门钩以后,操作人员就绕天车钩尖挂上索链。但这样仍不牢靠,其原因是钩尖遮挡太小,当龙门钩接触钢包或钢包车轴后, Tianjin No.3 Steel Mills hoisting steel ladle with gantry crane, due to the lack of safety devices, there has been a decoupling accident. To this end, the factory formed a “triple combination” group, successfully tested in the gantry crane hooked safety chain (see photo), to prevent the occurrence of decoupling accident. At first, a hoop is added to the hook neck of the crane hook. The two sides of the clamp are respectively welded with a rope chain and a rope chain hook. After the crane hook is hung on the crane hook, the operator hangs the rope chain around the crane hook tip. However, this is still not reliable, because the hook tip shading is too small, when the gantry hook contact ladle or ladle axle,