Drill rod connecting device of anchor rod trolley

The invention provides a drill rod extension device of an anchor rod trolley. The drill rod extension device comprises a lifting mechanism, a pushing mechanism, a jacking mechanism, a drill rod box, a drill rod, a rock drill and a propelling beam. A plurality of drill rods are stacked in the drill rod box, and the jacking mechanism jacks the drill rod on the upper layer to a set position; the infrared sensor sends an instruction to the lifting mechanisms after receiving the signal, and the paired lifting mechanisms clamp the drill rod by applying a certain clamping force and lift the drill rod to the position flush with the pushing mechanism; the pushing mechanism pushes the drill rod to the concentric position of the connecting sleeve of the rock drill, the rock drill rotates to enable the connecting sleeve to be connected with the new drill rod, and the rock drill advances forwards and continues to rotate to enable the front end of the new drill rod to be connected with the rear end of the original drill ro