A Harrington chain hoist is a manual lifting device that uses a hand chain pulled over a sheave to drive a geared load chain through a pocket wheel, raising or lowering a hook with large mechanical advantage. The pull on the hand chain rotates a planetary gear train coupled to a Weston-style load brake, which holds the load whenever the operator stops pulling. It exists so a single rigger can lift a 1/2 to 20 ton load without power, and it shows up daily in steel shops, theatre fly systems, and HVAC equipment rigging.
Harrington Chain Hoist Interactive Calculator
Vary load, chain travel ratio, and efficiency to see the hand-chain pull required and the effective mechanical advantage.
Equation Used
The calculator estimates required hand-chain pull from load force divided by the hoist travel ratio and overall efficiency. The default matches the article example: a 1/2 ton CB010 lifting 1000 lbf with about 60 lbf of hand pull, using the stated 30:1 class ratio and the implied combined efficiency.
- Load is in US short tons, where 1 ton = 2000 lbf.
- Static lifting only; shock loads and acceleration are not included.
- Travel ratio is hand-chain travel divided by load-chain lift.
- Efficiency represents gear, pocket wheel, chain, and brake friction losses.
How the Harrington Chain Hoist Actually Works
Pull the hand chain on a Harrington CB or CF series hoist and you rotate a hand chain wheel that drives the input pinion of a planetary gear reduction. That reduction — typically 30:1 to 80:1 depending on capacity — multiplies your pull force into hook torque, which the load chain pocket wheel converts back into linear force on a Grade 100 load chain. A 1/2 ton CB010 needs about 60 lbs of hand chain pull at rated load. A 3 ton CB030 needs the same 60-80 lbs because Harrington tunes the ratio to keep operator effort roughly constant across the range.
The critical part is the load brake, and this is where most chain hoists live or die. Harrington uses a Weston-style mechanical brake — two friction discs sandwiching a ratchet gear, with a pawl that only allows rotation in the lifting direction. When you stop pulling, the load tries to back-drive the gear train. The brake discs clamp onto the ratchet, the pawl locks, and the load holds. When you reverse the hand chain to lower, the threaded driver unscrews against brake friction just enough to let the load descend at controlled speed. If the friction discs glaze, contaminate with oil, or wear past spec, the load creeps or drops. If the pawl spring weakens, the ratchet skips under shock load. Harrington specifies brake disc thickness above 3.0 mm on most CB models — below that, replace immediately.
Load chain pocket geometry matters more than people realise. The pocket wheel has shaped recesses that mate with alternating vertical and horizontal links of the load chain. If you fit a non-OEM chain with even 0.2 mm pitch error, the chain rides up out of the pockets, jams the stripper, and you'll feel it as a hard catch on the hand chain. Always run genuine Harrington Grade 100 load chain matched to the hoist serial, not a generic replacement.
Key Components
- Hand chain wheel: Receives operator pull and converts it to rotary input torque. The hand chain to load chain travel ratio runs from about 30:1 on a 1/2 ton hoist to 100:1 on a 5 ton, which is why you pull more chain to lift the same height as capacity goes up.
- Planetary gear reduction: Multiplies input torque from the hand chain wheel into the load chain pocket wheel. Harrington uses hardened alloy steel gears running in a sealed grease pack — typically 30:1 to 80:1 depending on rated capacity.
- Weston-style load brake: Holds the load when the operator releases the hand chain. Two friction discs clamp a ratchet gear; the pawl locks reverse rotation. Brake disc minimum thickness is around 3.0 mm — wear past that limit and the load will creep.
- Load chain pocket wheel: Shaped sheave that engages alternating links of the Grade 100 load chain. Pocket pitch must match chain pitch within 0.2 mm or the chain will ride up and jam the stripper plate.
- Stripper / chain guide: Forces the load chain out of the pocket wheel after engagement and routes it to the chain container. A worn stripper lets the chain wrap and double-feed, which jams the hoist solid.
- Top and bottom hooks with safety latches: Forged alloy steel hooks rated to the same WLL as the chain. Throat opening must not exceed the manufacturer's reject dimension — a 15% throat increase indicates yielding and the hook must be retired.
- Load chain (Grade 100): Heat-treated alloy steel, typically 6 mm to 11.2 mm depending on capacity. Working load limit on 6 mm Grade 100 is about 1.6 tons single-fall. Replace at 5% wear on link diameter.
Industries That Rely on the Harrington Chain Hoist
You'll find Harrington hoists anywhere a crew needs to lift a heavy load without power — temporary rigging, low-headroom maintenance, equipment installs, and entertainment work. The CB hand chain hoist and LB lever hoist series cover most of it.
- Structural steel erection: AISC member fabricators use Harrington CB020 2-ton hand chain hoists rigged from beam clamps to plumb columns and align connection plates before bolt-up.
- Theatre and entertainment rigging: Cirque du Soleil and Broadway venues rig Harrington CF electric chain hoists and CB manual hoists on truss for set pieces and scenic flying — manual units for fine adjustment, electric for show moves.
- HVAC equipment installation: Mechanical contractors lift rooftop air handlers and chiller compressors with Harrington LB lever hoists when crane access is blocked — typical 3-ton LB030 on a Trane RTU swap.
- Marine and shipyard: Yard riggers at facilities like Bath Iron Works use Harrington 5-ton chain hoists for engine room equipment removal in confined spaces where powered hoists won't fit.
- Wind turbine maintenance: Service crews on Vestas V90 and GE 1.5 platforms hoist gearbox and generator components inside the nacelle using Harrington manual hoists rigged to the internal service crane rail.
- Bridge and infrastructure: DOT inspection and repair crews use 1-ton CB010 hoists hung from bridge underdeck rigging to lift bearing assemblies during seismic retrofit work.
- Heavy machine maintenance: Pulp mill millwrights pull rolls on a Voith paper machine using a pair of synchronised Harrington 5-ton hoists rigged to overhead I-beam clamps.
The Formula Behind the Harrington Chain Hoist
What every rigger actually needs to know is the hand chain pull force required to lift a given load — and how it scales across the working range. At light loads, friction in the gear train and brake dominates and you'll feel disproportionate effort relative to load. At rated load, Harrington tunes the ratio so a single operator pulling roughly 60-80 lbs can lift the WLL. Push past rated load and the brake starts slipping before the gears yield, which is by design — the brake is the weak link on purpose. The sweet spot for sustained lifting is 50-80% of rated capacity, where pull force is comfortable and brake heating stays low.
Variables
| Symbol | Meaning | Unit (SI) | Unit (Imperial) |
|---|---|---|---|
| Fhand | Hand chain pull force required at the operator's grip | N | lbf |
| W | Load weight on the bottom hook | N | lbf |
| rload | Effective radius of the load chain pocket wheel | m | in |
| rhand | Effective radius of the hand chain wheel | m | in |
| i | Internal gear reduction ratio (planetary stage) | — | — |
| η | Combined mechanical efficiency of gear train and brake | — | — |
Worked Example: Harrington Chain Hoist in an HVAC rooftop unit lift
A mechanical contractor in Calgary is lifting a 1,800 lb Carrier 48TC rooftop unit compressor section about 3 ft up onto a curb adapter using a Harrington CB015 1-1/2 ton hand chain hoist rigged to a beam clamp on the existing RTU rail. Hand chain wheel radius is 75 mm, load chain pocket radius is 22 mm, gear reduction is 36:1, and overall efficiency runs around 0.72 on a well-maintained CB unit.
Given
- W = 1800 lbf (8006 N)
- rhand = 75 mm
- rload = 22 mm
- i = 36 —
- η = 0.72 —
Solution
Step 1 — at the nominal lift load of 1,800 lbf (8006 N), compute the hand chain pull force:
That's a comfortable two-handed pull — well within what a single rigger can sustain for the dozen or so cycles needed to walk the compressor up 3 ft.
Step 2 — at the low end of typical operating range, lifting just the rigging slings and shackles at about 200 lbf (890 N):
Almost nothing — the hand chain feels like it's pulling itself. Most of what you feel at this load is gear-train drag and brake stiction, not actual lifting work.
Step 3 — at the high end, near rated capacity of 3,000 lbf (13,344 N) on a CB015:
Still inside the 60-80 lbf comfort band Harrington designs around, because the CB015 is sized so a single operator can hit WLL without strain. Push to a 2x overload — say someone tries to lift 6,000 lbf — and predicted pull jumps to 68 lbf, but the Weston brake will start slipping before you ever feel that, which is the safety feature working as intended.
Result
Predicted hand chain pull at the 1,800 lb compressor lift is about 20. 4 lbf — a light, easy pull. The low-end (slings only) sits near 2.3 lbf where the operator mostly feels gear drag, and the high-end (rated 3,000 lb) reaches 34 lbf, still comfortable for a single rigger; the sweet spot for repeated lifting is 50-80% of rated capacity. If you measure 35-40 lbf instead of the predicted 20 lbf, check three things in order: (1) gear grease has dried out or contaminated with grit, dropping η from 0.72 to 0.50 and feeling like the hoist is binding; (2) the load chain is pitch-mismatched and riding high on the pocket wheel, which adds a periodic hard catch every revolution; or (3) the brake friction discs are glazed and dragging on the ratchet during lift instead of releasing cleanly, which you can confirm by listening for a rasp at the top of each pull stroke.
When to Use a Harrington Chain Hoist and When Not To
A Harrington hand chain hoist isn't always the right tool. The decision usually comes down to lift duty cycle, headroom, operator availability, and budget. Compare against a lever hoist (come-along) and an electric chain hoist on the dimensions that actually matter to a working rigger.
| Property | Harrington Hand Chain Hoist (CB) | Lever Hoist / Come-along (LB) | Electric Chain Hoist (ER2/NER2) |
|---|---|---|---|
| Lift speed at rated load | ~0.8-1.5 ft/min (operator dependent) | ~0.5-1 ft/min (ratchet stroke limited) | 8-32 ft/min (motor speed) |
| Capacity range | 1/4 ton to 20 ton | 3/4 ton to 9 ton | 1/8 ton to 25 ton |
| Headroom required | Moderate (12-20 in. typical) | Compact (8-14 in.) | Largest (16-28 in. with motor body) |
| Power requirement | None — manual | None — manual | 115V / 230V / 460V 3-phase |
| Typical price (3-ton, 10 ft lift) | $650-900 USD | $400-650 USD | $2,500-4,500 USD |
| Best application fit | Vertical pulls, sustained lifts, overhead beam mounting | Horizontal pulls, tensioning, tight spaces | High-cycle production, repetitive lifts, no operator effort |
| Service life at typical duty | 20+ years light duty | 10-15 years light duty | 10 years at H4 duty class |
| Failure mode under overload | Brake slips at ~150% WLL (designed) | Handle bends or freewheel disengages | Motor stalls or thermal cutout trips |
Frequently Asked Questions About Harrington Chain Hoist
Creep on stop usually isn't the friction discs themselves — those tend to fail by total slip, not partial creep. The most common cause is oil or hydraulic fluid contamination on the brake discs, often from a crew member greasing the gear case and getting lubricant where it doesn't belong. The Weston brake relies on dry friction. Even a thin film drops the static coefficient enough to let the load creep until the pawl catches the next ratchet tooth.
Pull the brake cover, inspect the discs for any sheen or smell of oil, and replace them if contaminated — you cannot clean them back to spec. Also check the pawl spring tension; a weak spring lets the pawl float off the ratchet and miss teeth.
The formula assumes nominal efficiency around 0.72 for a well-maintained hoist. Real units in the field often run η = 0.55-0.60 because of dried grease, light corrosion on the gear teeth, or a chain container packed too tight pulling back on the load chain as it exits the stripper. Each of those drops efficiency 5-10%.
Quick check: disconnect the chain container and pull a short lift. If pull force drops noticeably, your container is the problem — the chain is binding inside it and adding back-tension. If pull is still high, schedule a gear case service.
Always size up. Operating a chain hoist at 100% WLL repeatedly puts the brake into its hottest, most-worn duty band. Brake friction discs see thermal cycling on every lift, and at WLL the disc temperature rises faster than it can dissipate between cycles. Service life on a hoist run continuously at 90-100% WLL is roughly half that of one run at 50-70% WLL.
Rule of thumb: pick a hoist rated 1.5-2x the actual working load for production duty. A 2,000 lb repeating lift goes on a 3-ton hoist, not a 1-ton hoist. The cost difference is small. The lifespan difference is large.
Chain skip almost always means the load chain pitch no longer matches the pocket wheel pitch. Two causes: someone fitted a generic replacement chain that wasn't matched to the hoist serial, or the original chain has stretched past 3% on link pitch from chronic overload. Stretched Grade 100 chain is permanently elongated — you cannot recover it.
Measure across 11 links with a caliper and compare to the Harrington spec for that hoist (typically printed in the manual). If the measurement is more than 2% over nominal, retire the chain immediately. A skipping chain will eventually jump the pocket entirely and drop the load.
No, and this is where a lot of riggers get it wrong. Hand chain hoists are designed for vertical pulls only. The top hook, the load chain alignment, and the stripper geometry all assume the load chain runs straight down from the body. Side-loading the top hook can yield the hook at loads well below WLL, and angled load chain causes premature stripper wear and chain twist that locks the hoist solid.
For horizontal or angled pulls, switch to a Harrington LB lever hoist — those are designed with a swivel handle and reinforced hooks intended for tension work at any angle. Or rig a snatch block to redirect a vertical hoist pull into the angle you actually need.
Measure the throat opening with a caliper and compare to the original spec stamped or documented for that capacity. ASME B30.10 calls for retirement at 15% throat opening increase — that's the failure mode for an overloaded hook, plastic deformation that opens the throat. A hook that opens 15% is one shock load away from straightening completely and dropping the load.
Also check for any twist in the hook body (more than 10° from neutral plane = retire), cracks at the saddle (any visible crack = retire), and wear at the saddle bearing point (more than 10% section loss = retire). Don't weld or repair — replace the hook with the Harrington OEM part.
References & Further Reading
- Wikipedia contributors. Hoist (device). Wikipedia
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