Unic URW546C Load Chart PDF + Specifications

The UNIC URW-546C is part of the company’s well-known spider crane series designed specifically for operations in confined or difficult access environments. The crane combines relatively high lifting capacity with compact dimensions that allow it to be transported through narrow entrances and operated inside buildings or on congested construction sites. The overall dimensions of the crane include a transport width of 1,380 mm, a height of 2,035 mm, and a total length of 4,870 mm, while the operational weight is approximately 4,930 kg, increasing to around 5,080 kg depending on equipment configuration.

The main lifting structure of the URW-546C consists of a six-section box-type hydraulic telescopic boom that extends from 3.93 m to 15.71 m. This boom design provides both rigidity and compact stowing dimensions while allowing the crane to reach a maximum hook height of approximately 16 m above ground level. When operating with a four-part reeving system, the crane can also reach up to 20 m below ground level, which enables lifting operations in shafts, basements, and underground construction areas. The crane’s maximum working radius is 15.52 m, providing sufficient reach for many installation and maintenance tasks.

The telescoping boom extends 11.78 m in approximately 35 seconds, while the boom raising mechanism moves from 0° to 80° in about 18 seconds. Lifting operations are handled by a high-performance hydraulic winch system equipped with an 8 mm diameter wire rope with a total length of 91.5 m. The winch delivers a single-line lifting speed of up to 44 m/min, while the hook speed with a four-part line reaches approximately 11 m/min. The crane uses a 4-tonne hook block with two sheaves and a safety latch to ensure secure load handling during lifting operations.

The superstructure of the URW-546C is capable of 360-degree continuous slewing on a ball-bearing race with a slewing speed of approximately 2.5 rpm, allowing precise positioning of loads around the crane. Stability during lifting is provided by a hydraulically operated outrigger system with double-acting cylinders and an automatic locking mechanism, enabling the crane to adjust to different ground conditions and restricted working areas. The hydraulic system is powered by a variable delivery piston pump, with operating pressures of 20.6 MPa for crane functions and 21.6 MPa for crawling operations. The hydraulic oil tank capacity is 75 litres, ensuring consistent hydraulic performance during extended work cycles.

Mobility for the URW-546C is provided by a crawler undercarriage designed for maneuverability and stability. The crane has a maximum travel speed of up to 3 km/h, with independent hydraulic drive motors for the left and right tracks, allowing precise steering and positioning. The crawler tracks measure 1,750 mm in length and 300 mm in width, producing relatively low ground pressure of approximately 46–47 kPa, which allows the crane to operate on delicate surfaces such as finished floors or sensitive ground conditions. The machine also offers a maximum gradeability of approximately 23 degrees, enabling it to travel across moderate slopes on construction sites.

Power for the crane is supplied by a Yanmar 3TNV80F diesel engine with a displacement of 1,266 cc. The engine produces a maximum output of 15.2 kW (20.7 PS) at 2,500 rpm and is supported by a 40-litre fuel tank, providing sufficient endurance for extended lifting operations. For applications requiring low noise and zero emissions, such as indoor work or enclosed facilities, the URW-546C can also be equipped with an optional electric power unit rated at 7.5 kW, operating on AC 200 V or AC 400 V three-phase power supply.

In terms of safety and operational systems, the crane incorporates a wide range of protective features typical of UNIC mini crawler cranes. These include radio remote control operation, automatic overwind protection, boom angle indicators with load monitoring, winch braking systems, and emergency stop functions. Additional safety equipment such as a safe load indicator, digital load meter, overload protection system, and outrigger ground contact detection can also be installed depending on the configuration. These systems help ensure safe and efficient crane operation even in complex lifting environments.

Overall, the UNIC URW-546C is designed as a versatile mini crawler crane capable of performing lifting tasks in locations where traditional cranes are unable to operate. Its combination of compact dimensions, 4-tonne class lifting capacity, reliable diesel power, and optional electric drive system makes it well suited for applications such as glass installation, steel structure erection, building renovation, and mechanical equipment placement in confined spaces.