在塔吊起重臂上都有一个随小车行走且又可上下运动的吊钩。为防止钩中的索具滑出，通常在钩头上加装一个像塔舌样的卡具，称为钩头保险装置，在使用中起到防止吊重意外脱钩作用。但塔舌比较简易，不耐用、易损坏，损坏后又难以修配，加之一般情况下起吊货物有无钩头保险装置无 On the crane tower crane has a walking with the car and can move up and down the hook. In order to prevent the sling from slipping out, it is common practice to add a tongue-like clamp on the hook head, called the hook head safety device, to prevent accidental unhooking of the hoisting hook during use. However, the tongue is relatively simple, not durable, easy to damage, damaged and difficult to repair, combined with the general situation under the hook with no cargo insurance device