Crab Units (Double Girder Hoists)
What is a Crab Unit in Crane Systems?
A Crab Unit refers to a compact lifting assembly that travels between the girders of a double girder overhead crane. It houses the hoist mechanism, motor, gearbox, rope drum, and trolley all on a robust frame.
Unlike monorail or underslung hoists, crab units are designed for:
- High lifting capacities
- Long spans
- Heavy-duty applications
Street Crane’s Crab Units offer the pinnacle of strength and span versatility — enabling precise lifting over wide bays and tall installations.
When Do You Need a Crab Unit?
Scenario | Why a Crab Unit is Ideal |
Lifting more than 20 tonnes | High capacity up to 250 tonnes |
Operating across long spans | Custom widths up to 40 meters |
Needing central hook positioning | Trolley between girders ensures precise centering |
Heavy usage | FEM M6–M8 rated for intense duty cycles |
Complex load handling | Multiple hook synchronization available |
If your operation requires consistent, heavy-duty performance — from foundries to fabrication shops — crab units provide unmatched durability and control.
Street Crane’s Crab Unit Capabilities
Lifting Capacity
- From 5 to 250 tonnes standard
- Higher capacity options available on request
Span Width
- For crane spans up to 40 meters or more
- Optimal for wide bay coverage
Hoist Type
- Modular wire rope hoists
- Available in single or twin drum design
Travel & Control
- Trolley travel via frequency inverter drives
- Micro-motion control for precision positioning
- Full synchronization with crane bridge motion
Compliance & Safety
- Overload protection, emergency limit switches, and sway control
- Safety protocols in line with EN, ISO, and FEM standards
Typical Applications for Low Headroom Hoists
Industry | Application |
Steel & Foundries | Mold and billet handling in harsh conditions |
Shipbuilding | Moving blocks and heavy marine components |
Energy & Power | Generator and transformer installation |
Heavy Fabrication | Lifting large structural elements |
Oil & Gas | Pipe racks, skids, and module handling |
Paper & Pulp | Machine roll loading/unloading |
Aerospace | Aircraft components and tooling lifts |
- Customizable frame width for non-standard spans
- Dual or single hoist operation for synchronized lifts
- High hook path travel for tall industrial bays
- Long wheelbase for increased stability
- Engineered for seismic and offshore conditions on request
- Full compatibility with load monitoring systems, anti-collision, and automation protocols
Benefits of Street Crane Crab Units
Al Waha Cranes – Trusted Regional Installer
As Street Crane’s regional integrator, Al Waha Cranes provides:
- Full design & installation of double girder EOT cranes with crab units
- Local fabrication of girders and end carriages
- Seamless integration with VFD panels, remote controls, and safety devices
- Complete after-sales support in UAE, KSA, Oman, and Qatar
With over 60+ years of team experience in crane engineering, we ensure that your crab unit installation meets both your lifting goals and space constraints.
Parameter
Value
Lifting Capacity
5–250 tonnes
Hoist Type
Wire Rope
Mounting
Between Double Girders
Trolley Travel
Frequency-controlled motors
Span Range
Up to 40+ meters
Controls
Pendant, Radio, or PLC-VFD panels
Duty Classes
FEM M6–M8, ISO A6–A8
Technical Summary
Frequently Asked Questions
A crab unit allows for precise load positioning between the girders, enabling high-capacity lifts across wide spans with better stability and safety.
Crab units utilize the space between the two girders, optimizing headroom and allowing more lift height than underslung or single girder hoists.
Yes, Street Crane crab units can be integrated with automation systems, including load cells, anti-collision systems, and programmable logic controls.
Yes, ATEX-certified crab units are available for use in oil & gas, chemical, and other hazardous environments.
