UNIC URW-546 Mini Spider Crane

Model URW-546 | 4.0t × 2.5m Max Capacity | 1.4m Width | 16m Lift Height | Tier 4 Yanmar Diesel + Optional 400V | Working Area Limitation Standard

The UNIC URW-546 offers an optimal combination of working flexibility and heavy lifting power. This crane is capable of lifting 4 tonnes at 2.5m and features a maximum lifting height of 16m. The URW-546 sees the addition of a clean-emissions Tier 4 Yanmar diesel engine. At 1.4m wide the URW-546 is ideal for passing through internal industrial doorways and working in confined areas. Control from the driver’s seat or via radio remote for precise placement, with an optional radio remote with digital feedback display available.

Technical Specifications

Specifications above are taken from the UNIC manufacturer's spec sheet at standard configuration. Variants with electric, LPG or other options may differ slightly — full rated capacity charts supplied with each hire.

Key Features

• 4 tonnes at 2.5m radius — from a machine just 1.4m wide — passes industrial doorways
• Tier 4 Yanmar diesel — clean-emissions engine for compliance on emission-sensitive sites
• Optional 400V mains electric dual power — zero length increase when fitted
• Working area limitation (optional) — with slew limitation and variable footprint upgrades
• Onboard or radio remote control — with optional digital feedback radio remote
• 700kg fly jib option — extends maximum lift height to 18.46m with fixed hook

Suitable Applications

The URW-546 is the standard mid-large UNIC for industrial doorway access combined with 4t capacity. Used for structural steelwork in atria, plant placement in high-bay industrial buildings, glass and curtain wall installation, and any internal lift demanding 4 tonnes at depth or height. Its Tier 4 engine and electric option keep it compliant on low-emission and indoor sites.

How to Set Up and Operate the URW-546

1. Survey the working area, verify ground bearing capacity against the published point loadings and confirm overhead clearances are sufficient for the proposed boom geometry.
2. Track the crane into position using the operator's seat or radio remote. Ensure the chassis is on firm, level ground or that load-spreader mats are deployed.
3. Deploy the outriggers to the configuration required by the lift plan — set each outrigger angle and extension, ensuring stabiliser pads make full contact with the ground.
4. Level the crane using the bubble level / auto-level system and verify all outrigger interlocks are engaged before luffing the boom.
5. Configure the rope reeving (1-fall, 2-fall, 4-fall or 5/6-fall as applicable) to match the planned load and required rope length.
6. Set any working area, slew or height limits required by the lift plan via the safe load indicator interface.
7. Carry out a function test, confirm the moment limiter and voice warning system are operational, then lift to working position and complete the lift in accordance with the lift plan.
8. On completion, return the boom to the stow position, retract outriggers and secure the crane for transit or overnight parking.

Warning: Spider cranes must only be operated by CPCS / NPORS / equivalent-certified operators working to an approved lift plan. Never exceed the rated capacity at the relevant radius shown on the load chart. Power source: Tier 4 Diesel + Optional 400V Electric.

Safety Information

• The crane must only be operated by competent, trained and certified operators familiar with this specific UNIC model.
• A documented lift plan, prepared by an Appointed Person, is required for every lifting operation under LOLER 1998.
• Ground conditions must be assessed against the manufacturer's point loadings — supplied on request — before each lift.
• Outriggers must be deployed to a configuration that supports the planned load at the planned radius; mixed-extension configurations require a competent rating check.
• Never operate the crane outside the rated load chart, override the safe load indicator, or carry loads with the boom in an unintended configuration.
• Carry out daily pre-use checks of hooks, wire ropes, hydraulics, safety devices and the moment limiter prior to first lift each shift.

Inspection and Maintenance

Spider cranes must be subject to a Thorough Examination by a Competent Person at least every 12 months under LOLER 1998, with additional 6-month examinations required where the crane is used to lift persons. Daily pre-use checks should cover wire rope condition, hook and shackle integrity, hydraulic system, outrigger pads, tracks, safety devices and the safe load indicator. All WOLFF Onsite hire cranes are supplied with a current Report of Thorough Examination and full service history. Defects identified in service must be reported immediately and the crane taken out of use until repaired.

Frequently Asked Questions