Scaffold Double Couplers
The double coupler is a type of scaffolding coupler used to fix two scaffolding tubes at a right angle(90 degrees). It is called a scaffold double coupler, a double fixed coupler, a double coupler clamp, a right-angle coupler, a 90-degree coupler, a rigid coupler, etc.
Double couplers are classified into three types based on manufacturing method: pressed, drop-forged, and cast-iron.
The sizes of the double couplers are based on the outer diameters of the scaffold tubes they will fix, including 48.3mm, 60.3mm, 76mm, 89mm, etc.
The international safety standards for the double coupler are EN74, BS1139, JIS A 8951, ASTM, AS/NZS 1576 and CSA.
Wellmade is the leading double coupler manufacturer in China; we export scaffolding double coupler clamps worldwide. Send us an email to get the price now.
Double Couplers
Drop-forged double couplers are the most widely used scaffolding tube connectors in construction. They are forged from heated round bars with an 8.8 class bolt and nut. It is the heaviest double-coupler scaffolding clamp, which is the most stable, safe, and high-load-capable scaffolding coupler. Include British type, German type, Australian type, USA I bolt Type, Wedge type, etc.
Pressed scaffolding double couplers are formed and shaped from high-strength steel plates. BS1139 standard for O.D. 48.3mm scaffold tubes or JIS A 8951 Standard for O.D. 48.6mm STK 400 and STK 500 JIS scaffolding pipes. The pressed double couplers are also called scaffold fixed clamps.
BS1139 scaffolding double couplers are British standard scaffolding right-angle couplers forged and used to fix 48.3mm BS1139 4 Type (4mm thickness) scaffold tubes in construction. They are heavy duty meet up EN74 Class B with failure load of 30KN, can be zinc plated or hot dip galvanized.
Double Coupler Load Capacity
Scaffold double couplers Load Capacity Test Result
| 1. Double Coupler Slipping Force | |||
| Sample No. | Fs (kN,△1=7mm) | Fs (kN,1mm≦△₂≦S2mm) | |
| 1# | 20.17 | 20.26 | |
| 2# | 20.75 | 21.00 | |
| 3# | 19.92 | 20.15 | |
| 4# | 19.27 | 19.58 | |
| 5# | 21.39 | 21.11 | |
| 6# | 21.87 | 22.00 | |
| 7# | 18.97 | 19.32 | |
| 8# | 20.33 | 20.82 | |
| 9# | 21.47 | 21.94 | |
| 10# | 18.97 | 20.05 | |
| Fs,5% | 18.2 | 18.9 | |
| 2. Double Coupler Failure Force (Load Capacity) | |||
| Sample No. | Ff(kN) | ||
| 11# | 82.46 | ||
| 12# | 83.34 | ||
| 13* | 84.75 | ||
| 14# | 73.85 | ||
| 15# | 80.30 | ||
| Ff,5%/γR2 | 56.6 | ||
Double Coupler Load Capacity Test Conclusion
| EN74-1:2005 Couplers, spigot pins and baseplates for use in falsework and scaffolds-Part 1: Couplers for tubes-Requirements and test procedures | |||||||||
| Test Results: | |||||||||
| Test Clause | Test item | Test Requirement (Double coupler, Class B) | Test Result | Conclusion | |||||
| 7.2.1 | Slipping force | △₁ ≤7mm,Fs,5%≥10.0kN | △₁ ≤7mm,Fs,5%=18.2kN | Pass | |||||
| 1mm≤△₂ ≤2mm,Fs,5%≥15.0kN | 1mm≤△₂ ≤2mm Fs,5%=18.9kN | ||||||||
| 7.2.2 | Failure force | Ff,5%/γR2≥30.0kN | Ff,5%/γR2=56.6kN | Pass | |||||
| Note: | |||||||||
| 1. Fs,5%, Ff,5%, the 5%quantile for the 75% level of confidence. 2.γR2=1.25 according to EN 74-1. 3. Specification of tube for slipping force: Steel tube of φ48.3mmx3.2mm(wallthickness), Specification of Steel Bar for failure Force: Steel Bar of φ48.3mm | |||||||||
- Scaffold Double Coupler Weight List
| Scaffold Double Coupler Weight List | |||
| No. | Items | Specifications | Weight |
| 1 | British Double Coupler, Forged, 48.3mm | M12 Bolt + 21mm Cross Nut | 1.0 KG |
| 2 | British Double Coupler, Pressed , 48.3mm | M12 Bolt + 21mm Cross Nut | 0.85 KG |
| 3 | Germany Double Coupler, Forged, Normal, 48.3mm | M14 Bolt+22/19mm Flange Nut | 1.25 KG |
| 4 | Germany Double Coupler, Forged, Coarse Thread, 48.3mm | M14 Bolt+22/19mm Flange Nut | 1.25 KG |
| 5 | Australian Double Coupler, Forged, 48.3mm | M12 Bolt+23mm Flange Nut | 1.05 KG |
| 6 | USA I Bolt Double Clamp, 48.3mm | M14 Bolt+22mm Flange Nut | 1.55 KG |
| 7 | USA Wedge Double Coupler, 48.3mm | Wedge Pin | 1.5 KG |
| 8 | Reduction Double Coupler, 48x60mm | M14 Bolt+22mm Flange Nut | 1.38 KG |
| 9 | Reduction Double Coupler, 48x89mm | M14 Bolt+22mm Flange Nut | 1.65 KG |
| 11 | Korean Double Clamp | M12 Bolt + 17mm Nut | 0.65KG |
| 12 | Japanese Double Clamp | M12 Bolt + 17mm Nut | 0.65 KG |
Double Coupler VS Swivel Coupler
Double couplers fix two scaffold pipes at right angles, forming verticals, horizontals, anchors, etc. in scaffolding.
Swivel couplers fix scaffolding pipes at any angle in tubular scaffolding, forming diagonals in construction.
Scaffold Double Couplers
Double scaffolding couplers are double clamps that lock two scaffolding tubes in construction to form scaffold verticals, horizontals, etc. They are one of the basic scaffolding fittings in the tubular scaffolding system.
The double scaffold couplers are used not only for the tube-and-clamp system but are also compatible with scaffolding systems such as ringlock, cuplock, kwisktage, quick lock, scaffolding props, and sidework bridging scaffolding systems.
According to the sizes of the double scaffolding coupler, there are 48.3×48.3mm scaffold double couplers and reduction double couplers of 48x60mm, 48x76mm, and 48x89mm.
OD48x48mm scaffolding double clamps are the standard double clamps, while the reduction double couplers are used to connect standard scaffolding pipes to scaffold props or scaffolding bridge legs.
For anti-corrosion purposes, the double coupler scaffolding is zinc-plated (cold -galvanized) or hot-dip galvanised.
Double Coupler Scaffolding For Different Countries
As an important scaffold fitting, double couplers are designed for different shapes, weights, and load capacities in different countries, according to their scaffolding standards.
- British standard scaffolding double coupler: The most common scaffold double coupler is widely used in many countries, including the UK, Ireland, Russia, Gulf Countries, African countries, and Southeast Asia. It is in the weight of 1.0-1.05KG with an M12 bolt and a 21mm cross nut with a washer.
- German standard double couplers: Drop forged double couplers used in Germany and Poland. It is heavier than British standard double couplers, 1.25 kg with an M14 bolt and 22mm or 19mm flange nut. Germany double coupler is also designed with coarse threads, which makes it convenient for hot dip galvanising (the most durable galvanising in scafflding industry)
- USA standard double coupler: USA double couplers include an I-bolt double coupler and a wedge fixed clamp. I-bolt double couplers are drop-forged, with a weight of 1.55 kg, making them the heaviest double couplers in the scaffolding industry. They are used for steel scaffolding tubes. USA fixed wedge clamps are used to fix aluminium scaffolding tubes.
- Australian standard double coupler: Heavier, forged scaffold right-angle coupler weighing 1.05 kg with 23mm flange nut, conforming to AS/NZS1576.
- Japanese and Korean Double Clamps: Lightweight and pressed steel right-angle clamps fixing O.D.42-OD48.6mm scaffolding poles with a weight of about 650G.
Drop Forged VS Pressed Steel Scaffolding Double Couplers
For double coupler scaffolding, drop-forged and pressed double couplers are the primary right-angle clamps. Forged double couplers, forged from heated round bars and more durable, can withstand greater loads in tubular scaffolding construction and are used for both 3.2mm and 4.0mm tubular scaffolding.
While pressed double couplers are formed from steel plates, they are lighter in weight and also meet the EN74 BS1139 standard. Used most in the lighter tubular scaffolding system with a 3.2mm or less thickness.
Pressed Double Coupler Types
- British Standard (BS 1139) Pressed Double Coupler. Used as right angle scaffolding connector between two O.D. 48.3×3.2mm scaffold tubes.
- Japanese & Korean Standard （JIS A 8951) Pressed Right Angle Clamps: Used as scaffolding right-angle fittings between two Japanese standard scaffolding pipes (STK 400 or STK 500) with a thickness of 2.5mm or less. O.D 48.6mm
Cold Galvanizing VS. Hot Dip Galvanising
Scaffolding double couplers, whether forged or pressed, are steel clamps. They need to be protected by galvanising for long life and repeated use.
Scaffolding double coupler galvanising includes two types: cold galvanising and hot-dip galvanising.
- Cold galvanising, also known as zinc-plating or E-galvanising, has a zinc thickness of 8-15 microns. This galvanising is cheap and the most common galvanising for scaffolding steel double clamps.
- Hot dip galvanising is also called HDG. It is with a zinc thickness of 40-80 microns. Which is expensive in cost but best in durability.
Wellmade is the leading manufacturer of scaffolding couplers in China. We export scaffolding double couplers worldwide at top quality and a reasonable factory price. Send us an email to get the price now.