The chain coupling is one of the oldest flexible coupling designs still in widespread industrial use ¡ª for good reason. Its ability to transmit high torque from a compact, robust assembly, and its tolerance of moderate misalignment, make it the coupling of choice for low-speed, high-torque conveyor drives, packaging machinery, and industrial fans where other coupling types are either too large, too complex, or too maintenance-intensive for the available access. The EP-GL series chain coupling from Ever Power uses duplex (double-strand) roller chain running on hardened alloy steel sprockets, providing torque ratings up to 22,000 Nm in a sealed, greased-for-life configuration. Where higher misalignment accommodation is needed without lubrication, the HN pin-bushing coupling provides the alternative.
How a Chain Coupling Works
A chain coupling consists of two sprocket hubs ¡ª each fitted to one of the connected shafts ¡ª wrapped by a single loop of duplex (double-strand) roller chain that engages the teeth of both sprockets simultaneously. Torque is transmitted from one shaft to the other through the chain’s tensile load across the engaged sprocket teeth. Misalignment is accommodated by the small angular articulation that exists between chain links ¡ª the chain’s pin-and-bushing joints can adopt a slight angular set at each link position, allowing the coupling to operate across a small misalignment without rigid angular constraint.
A sealed nylon cover, bolted around the chain and both sprockets, retains the lubricating grease that protects the chain-to-sprocket contact zone. This cover also provides protection against contamination ingress ¡ª one of the practical advantages of a sealed chain coupling in dusty industrial environments where open elastomeric couplings accumulate abrasive particles.
EP-GL Chain Coupling Specification Reference
| Size | Chain Pitch | Bore Range (mm) | Rated Torque (Nm) | Max Speed (RPM) | Angular Tol. (¡ã) |
|---|---|---|---|---|---|
| GL-06B | 3/8″ (9.525mm) | 10¨C22 | 120 | 3,000 | 1.0¡ã |
| GL-08B | 1/2″ (12.7mm) | 14¨C32 | 320 | 2,500 | 1.0¡ã |
| GL-10B | 5/8″ (15.88mm) | 20¨C45 | 750 | 2,000 | 1.0¡ã |
| GL-12B | 3/4″ (19.05mm) | 28¨C60 | 1,500 | 1,800 | 1.0¡ã |
| GL-16B | 1″ (25.4mm) | 40¨C85 | 3,800 | 1,400 | 1.0¡ã |
| GL-20B | 1-1/4″ (31.75mm) | 55¨C110 | 8,500 | 1,200 | 1.0¡ã |
| GL-24B | 1-1/2″ (38.1mm) | 70¨C140 | 16,000 | 900 | 1.0¡ã |
| GL-28B | 1-3/4″ (44.45mm) | 85¨C160 | 22,000 | 700 | 1.0¡ã |
Chain Coupling vs Pin-Bushing Coupling ¡ª Choosing Between Them
The HN pin-bushing coupling is often compared directly to the chain coupling because both are used in similar medium-torque industrial drive applications. The key practical distinction is the lubrication requirement: chain couplings require periodic grease replenishment or sealed grease-for-life designs; HN pin-bushing couplings use elastomeric pin bushings that require no lubrication. In food processing, pharmaceutical, and clean-room environments, the no-lubrication advantage of the HN pin-bushing coupling makes it the preferred choice regardless of torque level.
| Criterion | Chain Coupling (GL Series) | Pin-Bushing Coupling (HN Series) |
|---|---|---|
| Lubrication | Required ¡ª sealed or periodic | None required |
| Misalignment Tolerance | Moderate ¡ª 1.0¡ã angular | Good ¡ª 1.5¡ã angular, 0.5 mm parallel |
| Max Torque (equivalent size) | Higher ¡ª metal-to-metal engagement | Moderate ¡ª elastomeric bushing limiting |
| Vibration Damping | Minimal ¡ª metallic engagement | Good ¡ª elastomeric bushings absorb peaks |
| Food/Clean Environment | Not recommended ¡ª grease contamination risk | Suitable ¡ª no lubrication, food-grade bushing available |
| Operating Temperature | Up to 120¡ãC (mineral grease) | Up to 80¡ãC (standard PU bushing) |
| Maintenance | Chain replacement every 2¨C4 years | Bushing inspection every 12 months |
Frequently Asked Questions
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