To help workers lift, handle, transport, and accurately position heavy objects overhead, assembly and manufacturing operations frequently use workstation bridge cranes or monorails. These systems incorporate load-bearing trolleys that travel upon one of two different track styles. Both patented track and enclosed track are highly configurable, thanks to versatile options and load handling characteristics. This enables a facility owner to customize a permanent, temporary, or modular overhead handling system that precisely meets process needs. The following explores the basic differences between the two track styles and their features.

Patented Track Systems

Constructed with hard alloy steel, patented track has an inverted-T profile. This profile offers both high strength and low deadweight. These features enable the construction of long track spans with minimum load transfer to the support structure. That allows the underrunning trolleys deployed in patented track cranes and monorails to lift and transport loads weighing up to 40 tons.

In powered systems, pneumatic or electric trolleys advance the loads. Patented track systems also support manual operations, where workers push the load forward. The machining that creates the patented track flange’s running surface delivers precise tolerances. That enables smooth travel and minimal wheel or surface wear. The exact tolerances of patented track also ensure smooth load transitions at connection points.

To accommodate different facility layouts or process flows, manufacturers can create patented track sections in a variety of profiles, including curves and inclines. For further customization, the system can incorporate interlocks, track switches, turntables and more. These components enable the design of complex monorail paths, allowing loads to travel to and from adjacent cranes, between bays, or into other buildings.

There are two different installation options for a patented track system: freestanding or suspended. Systems provided with a freestanding structure mounted to the floor are ideal for facilities with high ceilings or multiple overhead obstructions. Suspended systems hang from the ceiling via hanger rods constructed of high tensile steel for strength and durability. To avoid obstructions and create elevation changes, threaded rods can be used.

Enclosed Track Systems

Enclosed track workstation cranes and monorails feature fully contained track sections that provide the running surface for an underhung trolley’s wheels. The fabricated enclosure creates smooth travel. It also shields the track from dirt and debris that could obstruct the trolley wheels and make it difficult for them to roll.

Depending on the design, enclosed track systems can lift and transport loads weighing up to 3 tons. Manufacturers offer different track materials to accommodate different applications. These include extruded aluminum for lighter duty operations and high-strength, low-deadweight rolled steel for heavier duty needs.

To further customize an enclosed track monorail, manufacturers form the modular track sections in a range of profiles. They can also supply curves, interlocks, switches, turntables, and more to match the facility’s unique application and layout. System components bolt together for fast installation. This feature also supports easy reconfiguration or expansion as production needs evolve.

There are two installation options for enclosed track systems: suspended from the ceiling or mounted to a freestanding structure. In suspended systems, adjustable height hangers clamp or bolt on to the enclosed track. The hangers keep the track level; specific adjustments create inclines and declines. They also accommodate variable ceiling elevations and other obstacles. Freestanding enclosed track systems are ideal for facilities with high ceilings or overhead obstructions.

MMA Standards Apply To Both Track Styles

To ensure that patented track and enclosed track monorails and workstation cranes are safe, operations should purchase products manufactured to the standards established by the Monorail Manufacturers Association (MMA). The American National Standards Institute (ANSI) publishes both standards, which explain the safe design, engineering, manufacturing, operation, and service of the products. They include:

ANSI MH27.1 – Patented Track Underhung Cranes & Monorail Systems applies to systems whose trolleys or carriers travel on the lower flange of a patented track runway.

ANSI MH27.2 – Enclosed Track Underhung Cranes & Monorail Systems applies to systems whose end trucks travel on the internal flange of an enclosed track runway.

Both standards also cover curves, switches, transfer devices, lift and drop sections, and other components used with these track styles. There is also guidance for specifying and selecting the best type of monorail or workstation crane for an application. The standards further explore how to size the equipment to the loads, and detail recommendations for proper use, maintenance, and inspection.

Learn More About The Two Track Styles

Looking for additional information about patented track and enclosed track workstation bridge cranes and monorails? The members of the Monorail Manufacturers Association (MMA) are the industry’s leading suppliers of workstation crane systems. The group offers a variety of resources—including a product certification program, recommended practices for workstation cranes and patented track systems, and more—via its website at www.MHI.org/MMA.