Core adjustment for converting excavators into rotary excavators

Modification is not simply replacing parts, it needs to take into account power matching, structural strength, and construction stability. The main modification contents are as follows:

1. Power system: Ensure sufficient output of rotation and lifting force

Hydraulic system upgrade: The power head rotation and drill rod lifting of the rotary drilling rig require high flow hydraulic oil drive. The hydraulic pump and main valve of the excavator need to be adjusted (such as replacing the high displacement hydraulic pump), and an independent hydraulic pipeline needs to be added to connect the power head and lifting mechanism to avoid overloading of the original system.

Engine adaptation: If the excavator engine power is insufficient (such as less than 150 horsepower), the engine needs to be upgraded or the construction load needs to be limited (such as only used for drilling in soil layers, not hard rocks), otherwise it is easy to get stuck or stall due to insufficient power.

2. Homework organization: Replace the excavator bucket and install the core components of rotary excavator

Mast and guide frame: The rigidity of the excavator's original boom/arm is insufficient to ensure vertical drilling of the drill rod (which can easily cause hole inclination). A rigid mast (usually a rectangular steel structure) needs to be installed at the front end of the boom, and a "guide slider" is used to constrain the verticality of the drill rod; The bottom of the mast needs to be connected to the excavator chassis through hydraulic cylinders to adjust the drilling angle (vertical or inclined).

Power head: a core component that needs to be installed on the mast and driven by a hydraulic motor, with functions of "rotary cutting" and "axial feed" (rotation speed 0-60 revolutions per minute, feed pressure adjusted according to the weight of the drilling tool). The torque of the power head needs to be matched with the drilling tool (100-300kN · m for soil drilling and above 500kN · m for rock layers). If the excavator's power is insufficient, a low torque power head (limited to soil layers) can be selected.

Drill rods and drilling tools: Select drill rods according to construction requirements (such as telescopic drill rods for deep holes and integral drill rods for shallow holes), and match the drilling tools with "spiral drill bits" (soil layers), "rock drill bits" (soft rocks), or "sand scoop" (slag removal). The length of the drill rods should match the maximum operating radius of the excavator boom (usually the maximum drilling depth after modification is 10-20 meters, far less than the professional rotary excavation of more than 50 meters).

3. Stable system: prevent the whole machine from overturning during construction

When rotary drilling a hole, the downward cutting of the drill rod will generate a reaction force, and the weight of the drilling tool will increase when it is fully loaded with drilling debris. Therefore, it is necessary to enhance the stability of the excavator:

Adding counterweights: Add counterweights at the rear of the excavator (usually 1-3 tons based on the maximum weight of the drilling tool) to balance the overturning moment during drilling at the front end.

Leg modification: Some small and medium-sized excavators need to install hydraulic support legs (similar to crane support legs) on both sides of the chassis. During operation, the support legs should be extended to the ground to reduce the deformation of the chassis load, especially when constructing on soft soil foundations.

4. Control system: Added independent control panel

It is necessary to add a control handle in the cab to control the rotation of the power head, the lifting/lowering of the drill rod, and the adjustment of the mast angle. At the same time, a "depth sensor" (displaying the drilling depth) and a "pressure sensor" (monitoring the drilling resistance to avoid overload) should be installed. Some modifications will add a simple hydraulic oil temperature alarm function.