Two-action Drill Accelerator Type SZJQ can be stored energy by hydraulic spring. It should   be applied with Model QYⅡ Hydraulic Drilling Jar jointly. The drill collar and Hydraulic Jar (below the Drill Accelerator ) can function an accelerated effect when jarring operates as for making the stuck point gain more jarring force.

Meanwhile, it can decrease the damage of tremor produced by up-down jarring for drill tools above Drill Accelerator.