A lifting clutch is not an accessory — it is legally a lifting device, CE marked under the Machinery Directive, designed to the VDI/BV-BS 6205 guideline, and it must be inspected at least once a year by a qualified person, on the owner's responsibility. It has exactly three discard criteria, and a clutch meeting any one of them must come out of service immediately: plastic deformation (a twisted coupling link, pressure marks from rigging hardware); a crack in the sphere seat or coupling link; or wear beyond the limit — the internal rim opening h grown too large, or the lip thickness m worn too thin, both checked in seconds with a check gauge. Welding, bending, straightening, shortening or heating a clutch is never permitted. A damaged clutch is scrap.
1. It is legally a lifting device — start there
Most articles about lifting clutches compare ring clutches to claw clutches and stop. That comparison is the least important thing about the product. Here is the thing that actually changes how you buy, store and use one:
A lifting clutch is a lifting device. In Europe it falls under the Machinery Directive 2006/42/EC, which means it must carry a CE mark and be supplied with a Declaration of Conformity. It is designed and rated to the VDI/BV-BS 6205 guideline for lifting inserts and lifting insert systems for precast concrete elements. And, like every other lifting device on your site, it is subject to periodic expert inspection.
Three consequences that people get wrong:
- An unmarked clutch has no place on a site. No manufacturer, no load class, no CE mark, no batch number — then it cannot be traced, cannot be matched, and cannot be shown to be compliant.
- The inspection duty sits with the owner, not the supplier. Buying a compliant clutch does not discharge it.
- A clutch is consumable. It wears. It has an end of life, and there is a defined test for reaching it.
2. How the clutch actually holds — and why that matters for wear
In the spherical-head system, the clutch does not thread, bolt or clamp. Its claw slides over the anchor's forged ball head and locks under it. The whole load is carried on the underside of that head, bearing against the inside lip of the claw.
That is the whole reason the discard criteria are what they are. The lip is the load-bearing surface; as it wears, it gets thinner and the claw opens up. Both changes reduce how much of the ball head the claw is actually holding — and both are measurable.
Because the head is a ball, the clutch can be loaded axially, diagonally and laterally, over a stated load-angle range. That is exactly why it suits lifting, turning and tilting — but it also means the lip gets loaded at every angle, all over its surface, which is why clutches wear faster than people expect.
3. The three discard criteria
This is the part of the manual nobody reads. There are three criteria. Meeting any one of them means the clutch has reached its replacement state and must not be used again.
4. How wear is actually measured — the two dimensions
Wear is not judged by eye, and it is not "does it still fit". It is two dimensions on the claw, each with a limit that depends on the load class:
| Dimension | What it is | Which way it moves with wear | The rule |
|---|---|---|---|
| h | Internal rim opening of the claw | Grows ↑ | Must not exceed hmax for the load class |
| m | Lip thickness — the load-bearing lip | Shrinks ↓ | Must not fall below mmin for the load class |
Use the check gauge
Manufacturers supply a purpose-made check gauge that tests both dimensions in seconds — no callipers, no arithmetic, no judgement call from a fitter under time pressure. If the gauge passes where it should not, or will not seat where it should, the clutch is done. It costs almost nothing and it is the single most effective piece of safety equipment in this product family.
5. What you must never do to a clutch
A worn or damaged clutch turns up on every site, and on every site somebody suggests fixing it. The answer is always no.
Never — not once, not "just this lift"
Welding, strong heat, bending, straightening and shortening are prohibited on lifting clutches and transport anchors. They alter the metallurgy and the residual stress of a safety-critical component in a way that nobody can predict, verify or test on site. The rated capacity simply stops being a known quantity. A damaged clutch is scrap — cut it up so it cannot come back.
And one more: the extreme-load event
If a clutch has been subjected to an exceptional load — a snagged element, a dropped or slipped load, a jam — its bearing capacity may have been affected even if it looks fine. It must be examined out of cycle by a qualified person against the discard criteria before it goes back into use. "It still fits, so it's fine" is not an inspection.
6. The load-class system: safety by design, not by procedure
Clutches and anchors are grouped into matching load classes, and the geometry is arranged so that a clutch physically cannot be coupled to an anchor of the wrong load class. A mix-up isn't discouraged — it's impossible.
That is a genuinely good piece of engineering, because it removes the most obvious human error from the most dangerous moment of the job. But it has two implications people miss:
| Implication | What it means for you |
|---|---|
| Buy the clutch and anchor as a matched system | The class pairing is part of the safety case. Mixing brands and assuming compatibility defeats the design. |
| "It fits" ≠ "it's rated" | Fit is a geometric fact; rating is a tested one. Never infer the second from the first. |
| Marking is how you know the class | Manufacturer, load class, system, CE mark, batch number, operating symbol. Worn-off marks = unidentifiable = withdraw it. |
| Use the recess formers | They put the anchor at the right position and depth so the clutch can seat and rotate freely. Skip them and the clutch seats badly and wears fast. |
7. The inspection routine you can actually run
Markings legible? Manufacturer, load class, CE, batch. If you can't read the class, you can't use it.
Visible deformation or pressure marks? Twisted link, flattened areas from shackles.
Visible cracks around the sphere seat or link? Wipe it first — dust hides cracks.
Does the claw seat cleanly and rotate freely on the head? A clutch that has to be forced is telling you something.
Clean the clutch before anything else. This is step one of the inspection, not preparation for it.
Check criterion 1: plastic deformation.
Check criterion 2: cracks in sphere seat and coupling link.
Check criterion 3: wear — h and m, with the check gauge, against the table for that load class.
Record the result against the batch number. An inspection you cannot trace to a specific clutch is not an inspection.
8. Frequently asked questions
What is a lifting clutch and how does it work?
A lifting clutch is the reusable rigging component that connects the crane to a cast-in anchor in a precast element. For the spherical-head system, the clutch's claw slides over the anchor's forged ball head and locks under it, so the load is carried by the head — not by a thread or a bolt. It couples and uncouples in seconds and can take load axially, diagonally and laterally, which is why it suits lifting, turning and tilting. A ring clutch does the same job with a ring-and-cable body.
Is a lifting clutch legally a lifting device?
Yes. A lifting clutch is a lifting device and in Europe falls under the Machinery Directive 2006/42/EC, which means it must carry a CE mark and be supplied with a Declaration of Conformity. It is designed to the VDI/BV-BS 6205 guideline for lifting inserts and lifting insert systems for precast concrete elements. This is not paperwork: it is the reason an unmarked clutch has no place on a site.
How often must a lifting clutch be inspected?
At least once a year, by a qualified person, and the responsibility lies with the owner of the equipment — not the supplier. Shorter intervals are required where the working conditions demand it: frequent use, increased wear, corrosion, or exposure to heat. In addition, any clutch that has seen an extreme load event — a snagged or dropped load, a jam — must be examined out of cycle before it is used again.
What are the discard criteria for a lifting clutch?
There are three, and meeting any one means the clutch must be taken out of service immediately. 1) Plastic deformation — for example a twisted coupling link, or pressure marks caused by rigging hardware. 2) A crack in the sphere seat or the coupling link. 3) Wear beyond the permitted limit, measured as the internal rim opening (must not exceed its maximum) and the lip thickness (must not fall below its minimum). Clean the clutch before inspecting it, or you will not see the crack.
How is clutch wear actually measured?
By two dimensions on the claw: h, the internal rim opening, which grows as the claw wears and must not exceed a maximum for that load class; and m, the lip thickness, which shrinks as the claw wears and must not fall below a minimum. Manufacturers supply a purpose-made check gauge that tests both in seconds — if the gauge passes through where it should not, or fails to sit where it should, the clutch is finished. The limits are tabulated by load class in the manufacturer's application instruction and the governing regulation.
Can a lifting clutch be repaired by welding or straightening?
Never. Welding, strong heat, bending, straightening and shortening are all prohibited on a lifting clutch and on transport anchors. They alter the metallurgy and residual stress of a safety-critical component in a way nobody can predict or verify, so the load capacity becomes unknown. A damaged clutch is scrap. Cutting it up so it cannot be put back into service is the correct disposal.
What is the load-class system and why does it prevent accidents?
Clutches and anchors are grouped in matching load classes, and the geometry is designed so a clutch cannot be coupled to an anchor of the wrong class — a mix-up is physically impossible, not merely discouraged. This is safety by design rather than safety by procedure: it removes the most obvious human error from the most dangerous moment. It also means you must buy the clutch and the anchor as a matched system, and never assume that because a clutch fits, it is rated.
What load angles can a lifting clutch take?
The spherical-head clutch is designed for use in all lifting directions — axial, diagonal and lateral — with its permissible load stated over a load-angle range. That is exactly why it suits turning and tilting a precast element, where the pull direction changes throughout the lift. But the rating is stated for that range: read the permissible load for your actual angle, and use recess formers so the anchor sits correctly and the clutch can seat and rotate freely.
What marking should a compliant lifting clutch carry?
Manufacturer, load class, system designation, CE mark, batch/charge number, and the operating symbol. An unmarked clutch cannot be traced to a batch, cannot be matched to a load class, and cannot be shown to be compliant — so it cannot be legitimately used. If the markings have worn off, the clutch is no longer identifiable and should be withdrawn.
References
- Machinery Directive 2006/42/EC — the reason a lifting clutch is CE marked and supplied with a Declaration of Conformity.
- VDI/BV-BS 6205 — the guideline series for lifting inserts and lifting insert systems for precast concrete elements.
- DGUV rules for lifting equipment — the source of the annual inspection duty and of the replacement (discard) criteria.
Need CE-marked clutches matched to your anchor load classes?
20+ years of export experience. Lifting clutches, ring clutches and combination clutches, supplied as a matched system with the anchors — marked with manufacturer, load class, batch and CE. Application instructions and check gauges available. Quote in 24 hours.
