Kobelco RK120-3 / RK120M-3

Kobelco’s RK120 series comprises two rough terrain crane models tailored for diverse lifting needs — the RK120-3, with a maximum lifting capacity of 12 tonnes at 2.0 metres, and the RK120M-3, rated at 4.9 tonnes across various configurations. These cranes offer excellent mobility, easy setup, and outstanding performance within confined job sites.

The RK120-3 and RK120M-3 share the same basic chassis and upper structure layout but differ in their maximum rated capacities and load chart specifications. Both are equipped with a 4-section fully powered boom that extends from 5.3 metres to 23.8 metres, supporting a wide range of lifting operations. The optional jib comes in two stages (3.6 m / 5.5 m) and is hydraulically offsettable from 5° to 60°, allowing high-angle lifts even in tight spaces. The maximum lifting height is 30.0 metres when using the jib.

The hoisting speed reaches up to 125 m/min on the first layer, with multi-speed hoist modes for efficient lifting (low, mid, and high speed). Boom elevation ranges from -3° to 82°, with telescoping speeds of 25 seconds for boom extension and 18.5 seconds for retraction. The slewing system operates at 2.4 rpm, providing precise positioning during operations.

Powering both cranes is the Mitsubishi 4M50-TLE3A engine, a water-cooled, 4-cylinder turbocharged diesel delivering 129 kW (175 PS) at 2,700 rpm and 530 Nm of torque at 1,600 rpm. The engine is compliant with Japan’s latest environmental standards and features electronically controlled fuel injection for better economy and emissions.

The RK120 series features 2WD and 4WD drive systems, along with four steering modes: front, rear, four-wheel coordinated, and crab steering. This offers excellent maneuverability with a turning radius of just 3.8 metres in 4WS mode. The cranes are compact in design, measuring 7,540 mm long, 2,000 mm wide, and 2,815 mm high, and are ideal for urban infrastructure work or factory facilities.

The cab is ergonomically designed, offering excellent visibility and comfort. It comes equipped with safety glass, full suspension seat, air-conditioning, and a monitoring system that displays boom angle, radius, lifting height, and outrigger extension width. A left-side view auxiliary camera enhances the operator’s field of view.

Outriggers can be deployed in five stages (full: 4.7 m; minimum: 1.64 m), adapting to variable site conditions. Additional safety functions include the ACS load moment limiter, automatic boom soft stop, boom angle limiter, winch drum indicators, and various alarms.

Wire ropes used include 29 mm x 132 m for the main hoist and 29 mm x 66 m for the auxiliary. The hydraulic system features a 172 L oil tank capacity, powered by a twin tandem gear pump setup.

With a carbody weight of 14.1 tonnes and total vehicle weight of approx. 19.8 tonnes, the RK120 series balances mobility and lifting power. It’s an ideal solution for lifting operations where footprint and safety are paramount.