When the excavator is working, the roofproof machine can withdraw from backplate of cutting section to the back of the excavator, thus it greatly saves the space of roof proof.

• 掘进机工作时，护顶机构可以收缩折叠，从截割部护板退回到掘进机本体后部，最大程度地降低护顶机构的空间尺寸。