WLL 20 Ιδέες από πολυεστέρα Ton, 20000κιλά Ανυψωτική σφεντόνα βαρέων καθηκόντων

ΕΝΑ 20,000 kg polyester webbing sling is the heavy size that still folds into a bag. On a 240 mm two-ply band it weighs about 1 kg per metre — 11 kg at 10 m — so one rigger carries four of them to the lift and coils each one by hand. That is why this size, more than any other in the range, is bought by the set rather than by the piece: four legs of 20 t on a spreader is the standard answer to a 40–60 t load with four pick points.

Τεχνικές παράμετροι

One 20 t sling is rarely the whole lift

A single 20 t leg is a specific job — a plate bundle, a machine bed, one corner of a load. Most 20 t slings we ship go out in twos and fours, and the figure that matters is the figure of the set. It is not 20 t multiplied by the number of legs, because the load never shares evenly and the angle takes its cut first:

Two numbers on that table decide most orders. Four legs give 42 t, not 80 t — the 2.1 factor is the whole reason a 60 t load with four pick points is rigged as four 20 t legs rather than two 30 t ones. And a choked 20 t leg holds 16 t, which is the figure that catches buyers lifting pipe and tube: a band round a pipe is choked, so a 20 t sling is a 16 t sling until it goes under the load in a basket.

Duplex is what keeps this size portable

Two plies at 240 mm is the standard 20 t build, and the second ply is doing something specific: it carries the load in a band thin enough to fold flat and soft enough to choke. Where more abrasion resistance is wanted in a narrower band, ένα 200 mm three-ply build reaches 24 t — heavier per metre, stiffer to coil, and with more yarn behind a cut.

Neither is “stronger” in the abstract — both are proof tested, both carry 7:1. The duplex survives handling; the three-ply survives abrasion. If the load is the problem rather than the handling — a soft, polished or finished surface where 833 kg/cm is too much — the answer is a wider band: see the wide body webbing sling.

What a 20 t set has to get right

• Matched length. Legs in a set are cut and sewn to the same length within ±50 mm. Unequal legs put the whole load on the shortest one, and the label will not show it — only the tape measure will.
• One batch, one certificate. A set is proof tested and certified together, so the four legs are traceable as a set rather than as four unrelated slings.
• Numbered legs. Legs are marked 1 να 4 to match the rigging drawing, which is what makes a repeat lift repeatable and an inspection auditable.
• The pick points, not just the tonnage. Send the four pick point positions, the centre of gravity and the headroom. That decides the leg length and whether a spreader beam is needed to hold the legs inside 45°.

Where the 20 t size does the work

Precast panels and staircase units, where the band has to pass through a lifting loop without marking the face. Steel plate and section bundles, usually two legs in a basket. Machine beds, pumps, transformers and skid-mounted plant, where four legs and a spreader keep the base level. Pipe spools and coated tube, choked or in a basket — and there the 16 t choked figure governs. Marine and boatyard work, where a wet band is easier to handle than a chain and does not mark a hull.

What retires a 20 t sling — and what retires a set

• A cut at the eye throat. The eye is the highest-stress point and the first place a burr reaches; cut or worn stitching at the throat ends the sling.
• Ply separation or a blister. A soft bubble between the two plies means the band has been overheated or chemically attacked, and the strength has gone where it cannot be seen.
• An unreadable leg number or length. A leg that cannot be identified cannot be paired, so the set comes out of service with it — this is the failure that quietly breaks a four-leg lift.
• Grit and concrete dust. It works between the plies and abrades the yarn from the inside; a stiff, gritty band has lost strength without showing a mark.

Συχνές ερωτήσεις

Can a 20 t sling lift 25 tonnes in a basket?

In a basket at 0–45° it lifts 40 t, so 25 t is inside the rating — but only if both legs of the basket hang at that angle and the band passes under the load twice. Πνιγμένος, the same sling is a 16 t sling, so a 25 t choked lift needs a larger size.

How many 20 t legs do I need for a 60 t load?

Four legs at 0–45° give 42 t, which is not enough; four legs will not carry 60 t at any angle in this size. Either the load needs 30 t legs (four at 0–45°: 63 t) or it is a two-point lift with a spreader and larger single legs. Send the pick points and we will do the arithmetic with you.

Can I mix a 20 t sling with other legs in the same lift?

Not in a matched set. Legs of different length or capacity share load unevenly, and the label cannot tell you which leg is actually carrying what. Where a lift genuinely needs two sizes, it is a designed assembly — tell us and it is built and certified as one.

Is duplex weaker than a four-ply sling at the same tonnage?

Οχι. Both are proof tested to 2 × WLL and both carry a 7:1 factor; the figure on the label is the figure. Ply count changes thickness, flexibility and how much yarn sits behind a cut, not the rating at a given width and ply combination.

Do you supply the set with one certificate?

Ναί. Matched sets are proof loaded and certified together, with the leg numbers and batch printed on the band and repeated on the certificate.

Related slings and fittings

• 30 t webbing strop — the next size up, still rigged by hand
• 50 ton webbing sling — where the coil needs two people and a pallet
• Wide body webbing sling — when the load cannot take 833 kg/cm
• Eye and eye webbing slings — flat, twisted and reinforced eyes
• Polyester round slings — the sleeved form where the load is round
• Συσκευές ανύψωσης — shackles, hooks and master links for a 20 t set
• All polyester webbing slings — 0.5 t να 50 t

Send the load, the number of pick points, the hitch and the length eye to eye. We will confirm the ply, the eye, the set configuration and the marking, and quote before the bands are woven.

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