The invention discloses a tire portal crane capable of automatically changing span, which comprises a main beam assembly, two support leg assemblies are mounted on two sides of the bottom of the main beam assembly, one support leg assembly is fixedly connected with the main beam assembly, the other support leg assembly is slidably connected with the main beam assembly, and the main beam assembly is fixedly connected with the main beam assembly. And cart walking assemblies are fixedly mounted at the bottom ends of the two supporting leg assemblies. According to the two supporting assemblies of the tire portal crane, one supporting leg assembly is fixed to the main beam assembly, the other supporting leg assembly can move back and forth along the main beam assembly, angle steering can be carried out according to the requirement of a site, the perpendicularity of the supporting leg assembly is detected through an angle sensor during steering, and the perpendicularity of the supporting leg assembly is detected through an angle sensor. And the tire portal crane controller is used for controlling the transverse moving assembly to control the supporting leg assembly to move in the span direction, so that the automatic span changing function is achieved, the stability of tires in the walking process is effectively guaranteed, and the situation that steering affects tire hoisting deviation and affects hoisting safety is avoided.

本发明公开了一种能自动变跨的轮胎门式起重机，包括主梁总成，所述主梁总成底部的两侧安装有两个支腿总成，其中一个所述支腿总成与主梁总成固定连接，另一个所述支腿总成与主梁总成滑动连接，两个所述支腿总成的底端均固定安装有大车行走总成。本发明该轮胎门式起重机的两个支撑总成，通过一个支腿总成与主梁总成固定，另一个支腿总成可沿主梁总成来回移动，可根据场地的需要进行角度转向，在转向时通过角度传感器对支腿总成的垂直度进行检测，并通过轮胎门式起重机控制器控制横移组件控制支腿总成向跨度方向进行移动，从而实现自动变跨的功能，有效的保证了轮胎在行走过程中的稳定性，避免转向从而影响轮胎起重发生偏移，影响起重的安全性。