A-Frame Lifting Device Selection: Capacity, Span, and Height
An A-frame lifting device is a freestanding crane whose beam is carried by two angled legs braced into an “A” at each end — the shape that lets it stand on the floor with nothing anchored to the building. Choosing one comes down to four numbers in a fixed order: rated capacity, clear span, lift height, and beam length. Get the order wrong and you buy a crane that fits the load but not the room.
What is an A-frame lifting device?
The same machine the industry also calls a portable gantry crane. The A-frame refers to the leg geometry; “gantry” refers to the beam spanning between them. A trolley rides the beam and carries the hook point, and the lifting itself is done by a chain hoist hung from that trolley — bought separately and sized to the crane’s rated capacity.
People searching “A-frame hoist” are usually shopping for the whole assembly: the A-frame structure plus a hoist. eme manufactures the structure — portable aluminum gantry cranes from 1,100 to 22,000 lb — and every unit accepts a standard manual or powered chain hoist at the trolley.
How much capacity do I need?
Size to the heaviest single lift, with margin — not the average lift, and not the weight of the part alone. Rigging, spreader hardware, and the shackle all hang below the hook and count against the rating.
Two habits worth keeping:
- Round up a class, not down. Stepping from a 1 ton to a 2 ton crane is a modest purchase premium. Working around a crane that is one class short costs you on every lift that does not fit.
- Check what the neighbouring class shares. The 1100, 2200 and 4400 Series share one trolley family, and the 6600 and 11000 share another — so stepping up inside a family keeps your spare parts compatible.
The capacity selection guide works through the sizing in more detail, including how to treat awkward and shared loads.
What span do I need?
Clear span is the usable width between the legs — the number that decides whether the crane can straddle what you are lifting. Measure the widest thing that has to pass between the legs, including the pallet, cradle, or engine stand it sits on, then add working clearance for the crew.
A wider span is not automatically better. Span and rated capacity trade against each other on the same beam: the longer the beam, the lower the capacity it carries, because the load sits further from the supports. That is why capacity is quoted for a given beam length, and why the beam is chosen after the load is known.
What lift height do I need?
Three measurements, all of which have to work at once:
- Hook height needed — how high the load’s lifting point must travel, plus the height of the hoist and rigging hanging above it.
- Ceiling, door, and obstruction clearance — the top of the beam has to clear whatever is overhead, and the assembled crane has to get into the room.
- The doorway it passes through — adjustable-height A-frames drop in increments, so one crane can duck a low door and then work tall inside. This is often the difference between one crane serving a building and needing one per bay.
When does a portable A-frame beat a jib crane?
A jib crane sweeps a fixed circle around a pivot anchored to a column, wall, or foundation. Inside that circle it is excellent and it takes no floor space in the work zone. Outside it, the jib does not exist.
Choose the A-frame when:
- The lift point moves — different machines, bays, buildings, or customer sites.
- You cannot attach to the building — a leased space, a landlord restriction, or a floor that cannot take a moment-resisting foundation. An A-frame needs sound, level floor and nothing else.
- You would otherwise buy several jibs. One portable crane covering five stations is usually cheaper than five installations plus their foundations.
Choose the jib when the same station is worked continuously all shift — setup time and floor footprint favour it there. The full comparison is in gantry crane vs. jib crane.
When does a portable A-frame beat a forklift?
A forklift carries a load from underneath; an A-frame suspends it from above. That single difference decides most of these cases:
- The load has no fork access — a pump on its discharge connection, a motor bolted to a base.
- The lift comes up out of something — a pit, a wet well, a floor hatch. Forks cannot reach down a hole.
- The placement has to be precise — lowering onto mounting feet or aligning a coupling wants a suspended load a crew can guide by hand.
- The room is too tight to turn a truck around.
A forklift still wins outright on palletized material, long horizontal moves, and dock work — and at the higher capacities it is often the intended assembly aid for the crane itself. The detailed comparison is in gantry crane vs. forklift.
Steel or aluminum?
If the crane lives in one bay and never moves, steel is a reasonable buy. The case for aluminum begins the moment it has to move: a 1 ton aluminum A-frame weighs roughly 235 lb assembled and breaks into components one or two people carry, where steel at the same rating is a forklift job. Aluminum also does not rust out of service in washdown, cold-storage, or wastewater environments. Full trade-off in aluminum vs. steel gantry cranes.
The capacity classes
| Class | Rated capacity | Series |
|---|---|---|
| 1/2 ton | 1,100 lb | 1100 Series |
| 1 ton | 2,200 lb | 2200 Series |
| 2 ton | 4,400 lb | 4400 Series |
| 3 & 4 ton | 6,600–8,800 lb | 6600/8800 Series |
| 5 ton | 11,000 lb | 11000 Series |
| 10 ton | 22,000 lb | 22000 Series |
Every eme unit is designed to ASME B30.17, load-tested to 125% of rated capacity before shipment, and ships with a Certificate of Test and an engineer-stamped drawing.
Frequently asked questions
What is an A-frame lifting device called?
A portable gantry crane. “A-frame crane,” “A-frame gantry,” and “A-frame hoist” all describe the same machine — angled legs carrying a beam, standing free on the floor. The names are used interchangeably in the field; the glossary defines each precisely.
How do I know what size A-frame I need?
In order: rated capacity for the heaviest lift plus rigging, with margin; clear span wide enough for the widest load to pass between the legs; lift height that clears both the load’s travel and your ceiling and doorway. Beam length follows from the span. If you would rather describe the lift than specify it, send eme the details and a configuration comes back.
Can an A-frame lifting device move with the load on it?
Only when it is designed and rated for it, on level, prepared surfaces, within the operator manual’s limits — and the floor must be rated for the load. Every eme gantry is engineered to roll while fully loaded under those conditions; how loaded travel works covers the specifics.
Does an A-frame lifting device include the hoist?
No. A complete eme crane configuration is the beam, its matched trolley, the legs and casters. The chain hoist hangs from the trolley and is sized to the crane’s rated capacity — see gantry crane parts.
eme has been engineering lightweight and portable lifting equipment since 2003.