self-propelled drill

Taking into account the collapsed soil buried on the drilling unit became loosen after the hole collapsed and drill bit being buried, the self-rescue device applied the idea of squeezing the collapsed soil back to the hole wall.

考虑到塌孔埋钻事故发生后，埋在钻具上方的塌落土体结构较为松散，自救装置采用了将塌落土体挤回孔壁的方法。

This paper systematically introduces the composition and principle of a self-design and manufactured miniature NC drill machine's control system used for processing printing circuit board.

本文系统地介绍了自行设计与制造的加工印刷电路板微型数控钻床控制系统的组成及原理，并对各部分功能进行了分析。

Self-propelling and rotating drill has the characteristics that can drill in the formed hole automatically change direction along the original hole.

自进式水射流钻头具有欺软怕硬的特性，在已形成的孔中可以自动改变方向沿原孔钻进，能够有效地将已失效的瓦斯抽放孔修复。

When the hole is collapsing and drill bit is being buried, with the help of auxiliary lift of steel cable, it can use the self-rescue device fixed on the rodless drilling unit to startup the self-rescue.

通过在无钻杆钻具上方安装自救装置，当塌孔埋钻事故发生时，可以通过启动无钻杆钻具自救装置，在钢丝绳的辅助提升作用下，进行自救。