Four chain legs cannot all sit properly in one master link — they crowd, foul each other and load the link unevenly. A quad assembly solves it with three components: one master link that goes over the crane hook, and two intermediate links below it, two legs to each.
That arrangement keeps the legs separated, lets each hang in line, and loads the top link evenly. It is why a three or four leg sling needs a quad assembly rather than simply a bigger master link.
The assembly is supplied made up and certificated as a unit. Sizing is by chain diameter, and the Working Load Limit shown is for the assembly in its intended leg configuration.
Key Features
- Three components, supplied assembled: One master link plus two intermediate links, certificated as a unit
- For 3 and 4 leg slings: Keeps the legs separated and loads the top link evenly
- W.L.L. 5.05 t at 6/7 mm rising to 18 t at 13 mm: And beyond in the larger sizes
- Proof and breaking forces published: M.P.F. and M.B.F. given per size, so the margin is visible
- -40 °C to +400 °C: With derating above +200 °C
- Eight sizes: Chain 6 mm through 26 mm
Technical Specifications
| Product Code |
Part No. |
Chain Dia (mm) |
W.L.L. (t) |
M.P.F. (kN) |
M.B.F. (kN) |
D (mm) |
L (mm) |
W (mm) |
D1 (mm) |
L1 (mm) |
W1 (mm) |
Weight (kgs) |
| G10QA7 |
D18L13 |
6/7 |
5.05 |
123.8 |
198.1 |
19 |
135 |
75 |
13 |
60 |
38 |
1.38 |
| G10QA8 |
D22L16 |
8 |
6.95 |
170.4 |
272.6 |
23 |
160 |
90 |
16 |
70 |
34 |
2.38 |
| G10QA10 |
D26L20 |
10 |
10.4 |
255 |
408 |
27 |
180 |
100 |
19 |
85 |
40 |
3.81 |
| G10QA13 |
D32L22 |
13 |
18 |
441 |
706 |
33 |
200 |
110 |
23 |
115 |
50 |
6.57 |
| G10QA16 |
D38L26 |
16 |
27.7 |
679 |
1,087 |
38 |
275 |
150 |
27 |
140 |
65 |
11.45 |
| G10QA20 |
D50L32 |
19/20 |
41.55 |
1,020 |
1,630 |
50 |
350 |
190 |
33 |
150 |
70 |
23 |
| G10QA22 |
D56L36 |
22 |
50.25 |
1,230 |
1,970 |
56 |
350 |
250 |
36 |
170 |
75 |
31 |
| G10QA26 |
D60L40 |
26 |
60 |
1,470 |
2,350 |
56 |
400 |
200 |
40 |
170 |
80 |
34.3 |
Working Load Limits shown are for the assembly in its intended configuration. Full data for the larger sizes is in the user information sheet.
BS EN 1677-4 +25% of Loads | Grade 10 | 3 and 4 Leg | -40 °C to +400 °C | LOLER Ready
Meets the Working Load Limit performance requirements of BS EN 1677-4 plus 25% of loads. Grade 10 alloy steel with a grey painted finish. Marked with material grade, manufacturer’s identification, size, product ID mark and traceability code, and supplied with a certificate. Rated -40 °C to +400 °C, with reductions in Working Load Limit above +200 °C. Under LOLER 1998, thorough examination by a competent person at intervals not exceeding 12 months.
Suitable Applications
The top assembly on three and four leg chain slings: machinery lifting, fabricated assemblies, moulds and dies, precast concrete and any load requiring four points. The wide temperature rating extends its use into foundry, forge and heat treatment work. For single and two leg slings, a plain master link from the G10ML range is the correct component.
More About This Product
Shackles are the most-handled component in any lifting operation, and that is precisely why they wear out first. A sling gets rigged and derigged; a shackle gets rigged, derigged, dropped, driven over, thrown into a box and picked up by whoever needs one. Most lifting gear fails from a single overload; shackles fail from accumulated inattention.
The grade markings matter more than most people realise. A Grade 6 high tensile shackle to BS EN 13889 and a Grade 8 alloy shackle look similar and share the same body shape, but the alloy version carries considerably more at the same size. Once a shackle is in a box with fifty others, the only way to tell them apart is the marking — which is why an unmarked shackle has to be scrapped no matter how good it looks.
Understanding the Load Path
A shackle has two distinct load-bearing elements and they do different jobs. The bow takes the sling; the pin takes the load. Reverse that — put the sling on the pin and the load on the bow — and two things happen. The sling bears on a smaller radius than it was designed for, and any movement in the sling starts to rotate the pin.
On a screw collar pin that rotation is the failure mechanism. A sling shifting under a settling load, or vibration transmitted from plant nearby, will slowly unscrew the pin over minutes or hours. It rarely happens quickly enough for anyone to see it happening.
The second consideration is angle. A shackle loaded in line with the pin carries its full rating. Loaded at an angle across the bow it carries substantially less, and published derating tables cover a limited range of angles — beyond that range no figure is published because none applies. On a multi-leg sling every leg is at an angle by definition, which is why the bow shackle exists and why putting a multi-leg sling into a dee shackle is a genuine mistake rather than a preference.
How to Use
- Use the right assembly for the leg count: Three or four legs need a quad assembly. Two legs crowded into one link is a different and worse arrangement.
- Watch the included angle closely: On a four leg sling the angles compound. As the included angle widens, the tension in each leg rises sharply.
- Assume three legs carry the load, not four: Unless the load is genuinely rigid and the legs precisely equal, the fourth leg is stabilising rather than lifting. Size accordingly.
- Check the master link fits the crane hook: Freely, without being forced or able to tip.
- Derate above +200 °C: Use the figures in the user information sheet.
- Do not modify: Never weld, heat, machine, drill or repaint.
Warning: On a four leg sling, do not assume the load divides by four. Unless the load is rigid and the legs exactly equal, three legs take the weight and the fourth stabilises. Sizing on four equal legs is a common and serious overload.
Safety Information
- Never exceed the marked Working Load Limit for the number of legs and the included angle.
- Use components of the same grade throughout the assembly.
- The master link must fit the crane hook freely without being forced.
- Derate for included angle. As the included angle widens, the tension in each leg rises sharply.
- Operating range -40 °C to +400 °C, with derating above +200 °C.
- Withdraw any link showing wear beyond the manufacturer’s stated limit, elongation, distortion or cracks.
- Never weld, heat treat, machine or repaint.
- Assemblies built or altered require proof testing and recertification.
- Thorough examination by a competent person required at intervals not exceeding 12 months under LOLER 1998.
Inspection and Maintenance
Inspect all three components. Measure section diameter at the crown of the master link and at every bearing point where the intermediate links sit, and withdraw at the manufacturer’s stated wear limit — the contact points between master and intermediate links wear against each other and are easily missed. Check each link for elongation by measuring internal length, since stretch is evidence of overload. Look for nicks, gouges and cracking at the points of maximum curvature, and confirm the intermediate links still move freely on the master link without binding. Confirm markings and the traceability code remain legible on the assembly.
Downloads
Frequently Asked Questions
Q: Why not just use a bigger master link for four legs?
Because four legs crowd in one link, foul each other and load it unevenly. The quad assembly puts two intermediate links below the master link, two legs each, so every leg hangs in line and the top link loads evenly.
Q: Does a four leg sling really carry four legs’ worth?
Rarely. Unless the load is rigid and the legs precisely equal in length, three legs take the weight and the fourth steadies it. Standard practice is to size on three legs, and it is the assumption that most often causes overload.
Q: What do M.P.F. and M.B.F. mean?
Manufacturing Proof Force and Minimum Breaking Force. The proof force is what each assembly is tested to; the breaking force is the design minimum. Both are published per size so you can see the margin over the Working Load Limit.
Q: Can I build my own quad assembly?
Components can be assembled, but any made-up lifting assembly requires proof testing and certification by a competent person before use. Buying it made up and certificated saves that step.
