一、引言动臂式塔式起重机在最小幅度起吊最大起重量(此时臂架仰角最大,通常在60°～70°)时,如果吊具脱落或突然卸载,由于惯性力的作用,使臂架受到一个向上的冲击载荷,因此臂架有可能向后倾倒,从而引起整机倾翻,造成重大经济损失。所以,动臂式塔机都设有防臂架后倾的安全装置。常见有两种结构型式:其一,在塔头设 I. INTRODUCTION The maximum lifting capacity of the boom-type tower crane at the minimum lift (when the boom elevation angle is the largest at this time, usually 60° to 70°), if the sling falls off or suddenly unloads, the inertia force will make the boom The rack is subject to an upward shock load, so the boom may be tilted backwards, causing the entire machine to tip over, causing significant economic losses. Therefore, the boom-type tower cranes are equipped with safety devices that prevent the boom from tilting backward. There are two common types of structures: one is at the top of the tower.