Description
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What Is a Drum Shape Gear Coupling?
The TGL drum shape gear coupling — sometimes called a barrel-tooth or crowned-tooth gear coupling — is a mechanical power transmission component that connects two rotating shafts while accommodating angular, radial, and axial misalignment simultaneously. Unlike straight-tooth gear couplings, the drum-shaped (convex) tooth profile creates a larger contact surface under load, distributing stress more evenly across the flank and dramatically reducing edge loading. This design philosophy translates directly into longer operational life, lower vibration transmission, and reduced bearing loads at both connected machines. Whether your application involves paper mills in Yorkshire, steel rolling lines in Sheffield, pump stations along the Thames estuary, or marine gearboxes at UK ports, the TGL series has been engineered to meet the specific demands of these high-consequence environments. Ever Power manufactures these couplings to exacting tolerances, with material traceability and full dimensional inspection records available on request for UK clients operating under ISO 9001 or PED-regulated environments.
Core Performance Advantages
Drum-Tooth Profile
Convex tooth geometry enables simultaneous compensation of angular misalignment up to ±1°, radial offset, and axial displacement — without sharp edge contact that shortens coupling life.
High Torsional Stiffness
Steel-on-steel gear mesh delivers near-zero torsional backlash under rated load, making TGL drum shape gear couplings ideal for reversing drives and servo-controlled machinery where positioning accuracy matters.
Wide Speed Range
From TGL1 at 10,000 rpm down to TGL12 at 2,120 rpm with 2,500 N·m torque capacity — the twelve-size TGL range covers virtually every rotating machine found in UK manufacturing plants and utilities.
Grease-Lubricated Seal
Integrated O-ring and labyrinth seals retain grease in the tooth mesh zone and exclude contaminants, reducing maintenance intervals and supporting long-term reliability in dusty, wet, or chemical-laden UK industrial environments.
Compact Envelope
Short axial length relative to torque capacity simplifies retrofitting into existing machine frames where space between motor and gearbox is constrained — a common challenge in older UK factory installations.
Balanced for High Speed
Dynamic balancing option available for sizes TGL1–TGL6 above 6,000 rpm. Ensures smooth operation and minimal vibration transmission to connected bearings and frames — critical in turbomachinery and compressor duty.
Working Principle, Materials & Application Scenarios
The TGL drum shape gear coupling operates on the principle of external-tooth engagement between an inner sleeve (hub) carrying convexly crowned teeth and an outer sleeve (shell) with straight internal teeth of matching module. When the inner hub teeth — which are machined in a drum or barrel shape — mesh with the outer sleeve teeth, the crowned profile creates a rocking contact that allows misalignment motion without generating the bending moments that plague conventional straight-tooth designs. Grease retained within the sealed cavity lubricates the tooth flanks continuously, converting what would otherwise be sliding friction into hydrodynamic film separation at the contact zones, extending coupling life significantly beyond industry averages.
Material selection follows a rigorous engineering logic. Hubs and sleeves are precision-machined from medium-carbon alloy steel (typically 40Cr or equivalent) with induction hardening at tooth surfaces to achieve 52–58 HRC surface hardness while maintaining a tough, ductile core. Flanges and bolts use Grade 8.8 or Grade 10.9 fasteners verified to DIN standards. For corrosive environments such as offshore platforms, water treatment works, or chemical processing plants in the UK, stainless steel variants and special surface coatings are available upon request through our bespoke engineering service.
Typical UK application sectors include: rolling mill main drives in steel service centres across the Midlands; pump and compressor drives in North Sea support facilities; marine propulsion shaft couplings for vessels built on the Clyde and Tyne; wind turbine pitch drive systems; paper machine roll drives in Scotland and Northern England; and general gearbox-to-motor connections throughout food processing, water treatment, and power generation plants operating under UK HSE regulations.
| Hub / Sleeve | 40Cr Alloy Steel |
| Tooth Hardness | 52 – 58 HRC |
| Bolt Grade | 8.8 / 10.9 DIN |
| Seals | Nitrile / Viton O-ring |
| Lubrication | Grease-packed, sealed |
| Coating (std) | Phosphate + oil |
| Radial | 0.3 – 1.1 mm |
| Axial | ± 1 mm |
| Angular | ± 1° |
Technical Specification Drawings
TGL Series — Full Technical Specifications
| Type | Main Size (mm) | S | Shaft Hole d1, d2 (mm) | L (mm) | Torque (N·m) | Max RPM | Inertia (kg·m²) | Weight (kg) | Compensation (mm / °) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| D | B | A,B | C | A,B | C | A,B | C | Radial | Axial | Angle | ||||||||
| A,B | C | A,B | C | type | type | |||||||||||||
| TGL1 | 40 | – | 38 | – | 4 | 6.7 / 8.9 / 10.11 / 12.14 | – | 16/20/22/27 | 10 | 10000 | 0.00003 | – | 0.20 | – | 0.3 | ±1 | ±1 | |
| TGL2 | 48 | – | 38 | – | 4 | 8.9 / 10.11 / 12.14 / 16.18.19 | – | 20/22/27/30 | 16 | 9000 | 0.00006 | – | 0.278 | – | 0.3 | ±1 | ±1 | |
| TGL3 | 56 | 58 | 42 | 52 | 4 | 10.11 / 12.14 / 16.18.19 / 20.22.24 | same | 22/27/30/38 | 31.5 | 8500 | 0.00012 | 0.00015 | 0.428 | 0.533 | 0.4 | ±1 | ±1 | |
| TGL4 | 66 | 70 | 46 | 56 | 4 | 12.14 / 16.18.19 / 20.22.24 / 25.28 | same | 27/30/38/44 | 45 | 8000 | 0.00033 | 0.0004 | 0.815 | 0.869 | 0.4 | ±1 | ±1 | |
| TGL5 | 75 | 85 | 48 | 58 | 4 | 14 / 16.18.19 / 20.22.24 / 25.28 / 30.32 | same | 27/30/38/44/60 | 63 | 7500 | 0.00072 | 0.00088 | 1.39 | 1.52 | 0.4 | ±1 | ±1 | |
| TGL6 | 82 | 90 | 48 | 58 | 4 | 16.18.19 / 20.22.24 / 25.28 / 30.32.35.38 | same | 30/38/44/60 | 80 | 6700 | 0.0012 | 0.0015 | 2.02 | 2.15 | 0.4 | ±1 | ±1 | |
| TGL7 | 92 | 100 | 50 | 60 | 4 | 20.22.24 / 25.28 / 30.32.35.38 / 40.42 | same | 38/44/60/84 | 100 | 6000 | 0.0024 | 0.0027 | 3.01 | 3.14 | 0.4 | ±1 | ±1 | |
| TGL8 | 100 | 100 | 50 | 60 | 4 | 22.24 / 25.28 / 30.32.35.38 / 40.42.45.48 | same | 38/44/60/84 | 140 | 5600 | 0.0037 | 0.0039 | 4.06 | 4.18 | 0.4 | ±1 | ±1 | |
| TGL9 | 140 | 140 | 72 | 85 | 4 | 25.28 / 30.32.35.38 / 40.42.45.48 / 50.55.56 / 60.63.65.70 | same | 44/60/84/107 | 355 | 4000 | 0.0155 | 0.0166 | 8.25 | 8.51 | 0.6 | ±1 | ±1 | |
| TGL10 | 175 | 175 | 95 | 95 | 6 | 30.32.35.38 / 40.42.45.48 / 50.55.56 / 60.63.65.70 / 71.75 / 80.85 | same | 60/84/107/132 | 710 | 3150 | 0.052 | 0.0535 | 16.92 | 17.10 | 0.7 | ±1 | ±1 | |
| TGL11 | 210 | 210 | 102 | 102 | 8 | 40.42.45.48 / 50.55.56 / 60.63.65.70 / 71.75 / 80.85.90.95 / 100.110 | same | 84/107/132/167 | 1250 | 3000 | 0.1624 | 0.165 | 34.26 | 34.56 | 0.8 | ±1 | ±1 | |
| TGL12 | 270 | 270 | 135 | 135 | 10 | 50.55.56 / 60.63.65.70 / 71.75 / 80.85.90.95 / 100.110.120.125 | same | 84/107/132/164 | 2500 | 2120 | 0.4674 | 0.4731 | 66.42 | 66.86 | 1.1 | ±1 | ±1 | |
Note: Type A/B = standard; Type C = with intermediate spacer shaft. Radial and axial compensation values in mm. Angular in degrees. All specifications subject to revision — contact our UK technical team for latest approved drawings.
Manufacturing Facility & Custom Engineering
Ever Power’s manufacturing facility operates CNC gear hobbing centres, precision ID/OD grinding machines, and coordinate measuring machines (CMM) with traceable calibration — equipment that directly delivers the tight tooth profile tolerances required for high-performance drum shape gear couplings. Our quality system is certified to ISO 9001, and each batch of TGL couplings passes through gear tooth profile inspection, hardness verification, dimensional check against approved drawings, and assembly run-out measurement before despatch.
Custom engineering is a genuine strength here, not just a marketing claim. UK clients regularly specify non-standard bore diameters and keyway configurations, special shaft-end fits (H7/k6, H7/n6, interference press-fit), extended shaft lengths for spacer-shaft applications between widely separated machines, alternative flange bolt patterns to match existing coupling guards, and special coatings including Geomet, hot-dip galvanising, or electroless nickel for aggressive environments. Modified flange tooth counts to alter torque ratings and custom moment-of-inertia-matched designs for torsional vibration-sensitive systems are also handled within our engineering department. Lead times for standard TGL sizes are typically 2–4 weeks ex-works for UK delivery, with expedited production available for critical shutdowns.
Customer Success — Real-World Applications
Background: A medium-sized steel service centre in Nottinghamshire was experiencing repeated coupling failures on its bar rolling mill main drive, with standard straight-tooth gear couplings averaging only 7–9 months between replacements due to edge loading caused by thermal expansion misalignment of the mill housing.
Solution: Ever Power specified TGL9 drum shape gear couplings (355 N·m rated, 4,000 rpm, 0.6 mm radial compensation) to replace the failed units. The crowned tooth profile easily absorbed the 0.35 mm radial thermal offset measured at operating temperature. Grease-sealed design also eliminated the manual lubrication requirement that had been repeatedly overlooked during shift changeovers.
Outcome: Eighteen months into service with zero coupling-related stoppages. The client has since specified TGL couplings as standard for all future rolling line refurbishments across their two UK sites. Estimated maintenance cost reduction: approximately £18,000 per annum.
“We’ve installed TGL7 couplings on all three of our cooling water pump drives at our power station facility. Eighteen months in, not a single leak or tooth wear issue. The sealed grease design is a big advantage in our wet environment.”
“The custom bore and keyway configuration was delivered exactly to our drawing in under three weeks. Their engineering team answered every technical question we raised before the order. Will definitely use Ever Power again.”
“We’ve compared TGL drum couplings against two European brands on our paper machine dryer section. The TGL units ran measurably cooler at 3,200 rpm, which tells you the tooth geometry is genuinely better. Price-performance ratio is excellent.”
Frequently Asked Questions
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edit by gzl