12Ton 20Ton Excavator Tunnel Arm Excavator Shorten Arm

What is a tunnel arm for excavator?

A tunnel arm for an excavator, also known as a shortened arm or tunnel-specific boom, is a specialized attachment designed specifically for excavation and crushing operations in confined spaces such as tunnels, basements, and underground mining areas.
Because standard excavator arms are often too long for these restricted environments, the tunnel arm solves this issue by being intentionally shortened. This modification significantly reduces the machine's operating radius, allowing it to rotate flexibly and maneuver easily without colliding with tunnel ceilings, walls, or structural beams.

Key Features and Advantages:
Enhanced Power & Capacity: Despite its shorter length, the hydraulic cylinders (such as the bucket cylinder and intermediate cylinder) are typically enlarged and thickened to boost hydraulic power. This allows the excavator to handle larger buckets and heavier, more powerful breaker hammers, thereby increasing the striking force during rock-breaking tasks.
Safety Protection: Tunnel environments pose risks of falling debris. To prevent damage from stray rocks, protective covers are added to vulnerable components like the cylinders. Additionally, some advanced designs incorporate a shut-off valve at the front for better control.
Customization & Advanced Designs: Manufacturers can customize the dimensions of the arm based on specific tunnel height and width requirements. Furthermore, specialized patented versions feature a deflection mechanism that allows the arm to pivot left and right, enabling precise profiling and sweeping along the curved edges of the tunnel. Others utilize high-strength manganese steel and dual-directional tooth structures to withstand harsh conditions and improve continuous construction efficiency.

Two Types Excavator Tunnel Arm / Excavator Shorten Arm Shorten Boom:

Zhonghe Machinery's Excavator Tunnel Arm / Excavator Shorten Arm's Advantages: