The UNIC URW-546 offers an optimal combination of working flexibility and heavy lifting power — 4 tonnes at 2.5m with a maximum lifting height of 16m, now with the addition of a clean-emissions Tier 4 Yanmar diesel engine. At 1.4m wide it 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.
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
Technical Specifications
| Specification |
Detail |
| Crane capacity |
4.0t × 2.5m |
| Max working radius |
15.52m |
| Max lifting height |
16m (17.79m with fly jib, 18.46m with fixed hook) |
| Boom length |
3.93 – 15.71m (6 section) |
| Folded dimensions (L × W × H) |
4870 × 1400 × 2035mm |
| Unladen weight |
4940kg (5090kg with electric option) |
| Rope length |
20.52m (4 fall) / 42.54m (2 fall) / 86.57m (1 fall) |
| Engine |
Tier 4 Yanmar diesel, 17.8kW (23.9PS) |
| Electric motor |
7.5kW @ 400V AC |
| Slewing |
360° continuous, 2.5 rpm |
| Track width |
300mm |
| Travel speed |
0 – 3km/h (2-speed hydrostatic) |
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.
UNIC Cranes | LOLER Compliant | Hire from WOLFF Onsite
This UNIC mini spider crane is supplied by WOLFF Onsite for hire across the UK. All cranes are LOLER-tested and supplied with a current Report of Thorough Examination. UNIC has been manufacturing mini spider cranes for over 50 years and is the original spider crane brand — the patented stability protection, intelligent voice warning system and computer-controlled moment limiter set the safety benchmark for compact lifting. Operator training, on-site delivery and full technical support are available — contact our team to discuss your project.
More About This Product
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.
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
- Survey the working area, verify ground bearing capacity against the published point loadings and confirm overhead clearances are sufficient for the proposed boom geometry.
- 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.
- 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.
- Level the crane using the bubble level / auto-level system and verify all outrigger interlocks are engaged before luffing the boom.
- 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.
- Set any working area, slew or height limits required by the lift plan via the safe load indicator interface.
- 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.
- 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
Q: Can the URW-546 be operated indoors?
Yes, with the right power option. The URW-546 is available with an integrated electric option that allows clean, quiet operation suitable for indoor work, occupied buildings and low-emission zones. Engine-only configurations should be used outdoors or in well-ventilated areas only.
Q: Do I need a trained operator to use this crane?
Yes. All spider cranes must be operated by a competent, trained and certified operator (typically CPCS or NPORS certified). WOLFF Onsite can supply operated hire or arrange operator training as part of the package — please contact us for details.
Q: Is the URW-546 available for short-term and long-term hire?
Yes. WOLFF Onsite offers daily, weekly, monthly and project-length hire for the full UNIC URW range. Contact us with your project dates, lift plan and site address for a tailored quotation including delivery, off-load and operator if required.
Q: What are the point loadings I need to consider?
Spider crane point loadings vary with boom angle, radius and outrigger configuration, so they are supplied on a per-project basis. Provide your lift plan and proposed setup position and we will supply the relevant point loading data for ground bearing assessment.
