Kobelco RK70 / RK70M

The Kobelco RK70 / RK70M is a versatile rough terrain crane engineered for lifting tasks in tight and challenging work environments. This crane offers a maximum rated lifting capacity of 7,000 kg at 2.5 meters radius using the shortest boom (4.9 m) with six-part line reeving. As the boom extends through its sections—8.1 m, 11.3 m, 14.5 m, and up to the full 17.7 m—the maximum lifting capacity transitions accordingly, accommodating loads down to 4,000 kg with four-part reeving at longer boom lengths. With its boom plus jib configuration, the maximum working radius extends to 21.2 meters.

The boom elevates from -8.8° to 80.5°, reaching maximum elevation in about 27.5 seconds, while the swing speed is 2.3 rpm. The RK70 / RK70M uses high-strength IWRC 6xWS (26) wire ropes, each with a 10 mm diameter for both main and auxiliary winches, delivering a maximum hoisting speed of 111 m/min (main winch, 5th layer) and 104 m/min (auxiliary winch, 4th layer). The hydraulic boom extension system employs a synchronized multi-cylinder setup to ensure smooth and efficient extension of all sections.

Outrigger spread widths are 4.4 m, 3.0 m, or 1.65 m, allowing stable operation even in constrained spaces. The RK70 / RK70M features a two-stage gear pump system providing 149 liters per minute hydraulic flow for simultaneous multi-function operation. Key safety devices include overload protection with alarm, anti-two block system, drum locks, slew lock, boom angle limiters, and hydraulic safety valves on hoist, boom, swing, and outrigger circuits.

The carrier is powered by an Isuzu 4BD1 water-cooled, four-cylinder diesel engine producing 115 PS at 3,200 rpm, with maximum torque of 26.5 kg·m at 1,900 rpm. It offers selectable 2WD (4×2) and 4WD (4×4) drive modes via an electronic shift transmission. The maximum travel speed is 49 km/h, with gradeability of 40% (4WD mode) or 20% (2WD mode). The turning radius is a tight 4.04 m (4-wheel steer), enabling the crane to maneuver in narrow job sites.

Operator comfort and control are enhanced by features such as full-power steering, power-assisted reversing steering, advanced control levers, and optional cab air conditioning. The RK70 / RK70M also includes safety systems for brake actuation and hoist lever interlocks to prevent accidental operation.

Overall, the Kobelco RK70 / RK70M is a practical, maneuverable solution in the sub-7 ton rough terrain crane class, offering reliable lifting, ease of transport, and advanced hydraulic and safety systems for urban, industrial, and infrastructure projects.