Description
The flexible coupling family covers every industrial shaft coupling type that compensates shaft misalignment while transmitting torque — from the rubber-element tyre couplings used on pump sets across Australian water utilities, through the precision disc and diaphragm couplings specified for turbomachinery, to the HN flange-flexible coupling that replaces a rigid disc coupling in the same machine envelope. This guide places each flexible coupling type against the application that selects it, with detailed specifications on the HN flange-flexible pin-and-bushing range that bridges rigid and flexible coupling architectures.
HN Flange-Flexible Coupling Specifications
The HN flange-flexible coupling uses the same flanged disc form factor as a rigid flange coupling, with the addition of pin-and-bushing elements that transmit torque through a controlled rubber or polyurethane compression. The result is a moderate-misalignment flexible coupling in the dimensional envelope of a rigid coupling — the natural upgrade path where a rigid disc has been chewing bearings through alignment-induced loading. The HN range covers HN1 through HN6 spanning the bore range from 12 mm to 100 mm and the torque envelope from 16 N·m to 1600 N·m.
| Model | Nominal Torque (N·m) | Max Speed (rpm) | Bore Range (mm) | Outer Diameter (mm) | Angular Misalignment | Parallel Offset |
|---|---|---|---|---|---|---|
| HN1 | 16 | 5000 | 12 – 20 | 90 | 1° | 0.2 mm |
| HN2 | 40 | 4500 | 16 – 30 | 120 | 1° | 0.2 mm |
| HN3 | 100 | 4000 | 22 – 42 | 155 | 1° | 0.2 mm |
| HN4 | 250 | 3600 | 28 – 55 | 190 | 1° | 0.2 mm |
| HN5 | 630 | 3200 | 38 – 75 | 240 | 1° | 0.3 mm |
| HN6 | 1600 | 2800 | 50 – 100 | 300 | 1° | 0.3 mm |
Pin elements are heat-treated alloy steel; bushings are NBR rubber for general industrial duty or polyurethane for higher torque transmission and extended fatigue life. Polyurethane bushing variants tolerate elevated operating temperatures and resist oil contamination significantly better than the NBR variants — specify polyurethane for installations subject to oil mist or operating temperatures above 60°C. The HN coupling is supplied with both flanges and the pin-bushing set as one assembled item ready for installation.
HN Flange-Flexible Coupling – pin-and-bushing torque transmission in flanged disc envelope. Direct upgrade from rigid flange coupling. Ever Power Flange Couplings Australia Ltd.
How the HN Flange-Flexible Coupling Works
Two flanged hubs sit facing each other across a small axial gap, each hub carrying a circumferential row of bolt holes on the rated bolt circle. Steel pins pass through the holes on one flange and are clamped against the flange face; the pins extend into rubber or polyurethane bushings seated in the matching holes on the opposing flange. Torque transmission is through the compression of the bushings as the pins displace circumferentially under load — the misalignment compensation comes from the elastic deflection of the same bushings in radial and axial directions.
The flanged disc envelope preserves the same dimensional fit as a rigid flange coupling at the same torque rating. This is the key engineering proposition of the HN: where an existing installation has a rigid coupling but is now showing bearing wear from misalignment-induced loading, the HN drops in to the same bolt circle and the same shaft positions without any baseplate modification. The bearings then last 3 to 5 years instead of 6 to 12 months — the typical service life improvement when a rigid coupling is upgraded to a torsionally flexible coupling in a poorly aligned drive train.
When to Specify the HN Versus an Elastomeric Coupling
The HN coupling is specified where the application requires flange-disc dimensional compatibility — direct rigid-coupling replacement, or installations where the coupling guard envelope was designed around a flanged disc form. Where the application is unconstrained by an existing flanged envelope, full elastomeric couplings (tyre, jaw spider, or pin-bushing in non-flange form) provide broader misalignment compensation and higher shock absorption at lower cost. Choose HN for the dimensional fit; choose elastomeric for the engineering flexibility.
Complete Flexible Coupling Range Across the EP Catalogue
The flexible coupling family available from our Sydney warehouse covers the full engineering envelope of Australian industrial drive applications. Each coupling type below has a specific application domain where it represents the best engineering selection; the catalogue exists to put the right coupling type into the right application, not to push any single coupling product into every application. The summary below maps coupling type to selection criteria.
F40 to F250, 10 to 20,000 N·m, angular to 4° per element, lubrication-free. The most widely specified industrial flexible coupling type in Australia. Pumps, fans, diesel engine drives, conveyors. FRAS and ATEX compounds available.
3 to 680 N·m, to 10,000 rpm, zero backlash with 64D polyurethane grade. Compact envelope. Servo motors, small pumps, instrumentation drives, CNC auxiliary axes.
16 to 1600 N·m, flanged disc envelope, pin-and-bushing torque transmission. Direct upgrade from rigid disc couplings. Motor-to-gearbox connections in heavy industrial duty.
DBSE 80 to 180 mm, F40 to F140 tyre elements. Pump set maintenance access — withdraw rotor without removing motor. FRAS and ATEX compounds for hazardous-area service.
Up to 50,000 N·m, hardened steel spring element, progressive non-linear stiffness. 4× shock absorption of equivalent rubber-element coupling. Falk Steelflex T10 / T20 replacement.
GL3 to GL14, up to 4700 N·m, fastest field assembly through master link release. Different bores each end as standard. Agricultural PTO, portable plant, conveyor head drives.
Stainless laminar disc pack, zero backlash, 20,000+ rpm capability, lubrication-free. Turbomachinery, high-speed centrifugal compressors, precision servo positioning. API 671 documented orders supported.
Stainless diaphragm pack, zero backlash, -50°C to +300°C operating range, 10,000+ rpm. Gas turbines, steam turbines, high-temperature precision drives. API 671 standard turbomachinery applications.
Bore 3 to 40 mm, zero backlash split-clamp bores, ultra-compact single-body construction. Servo motor to encoder, stepper motor to ballscrew, CNC and instrumentation drives.
Industrial flexible coupling range across the EP catalogue – pumps, conveyors, turbomachinery, precision servo, agricultural, marine, mining drives. Sydney NSW warehouse stock.
Flexible Coupling Selection Decision Guide
The selection decision is driven by the single dominant engineering constraint of the application. If multiple constraints apply, the most restrictive one wins — typical applications have one constraint that rules out most of the catalogue and leaves a clear engineering selection. The guide below walks through the dominant constraints in approximate order of frequency across Australian industrial applications.
If the application is a servo-driven positioning system, a precision CNC spindle, a chassis dynamometer, or any drive where the angular position of the driven shaft must track the motor encoder without lost motion — the selection is the disc coupling, diaphragm coupling, or flexible beam coupling. All other coupling types introduce some backlash on torque reversal.
If the application is a jaw crusher, reciprocating compressor, loaded conveyor restart, or any drive with high cyclic peak torque — the selection is the snake spring (grid) coupling or the F-type tyre coupling. Both absorb shock through progressive deflection; the grid coupling absorbs more shock per unit size but requires lubrication.
If the application is a centrifugal pump set where the mechanical seal or pump rotor must be serviced without disturbing the motor alignment — the selection is the tyre spacer coupling. Standard DBSE values are 80, 100, 140, and 180 mm; FRAS compounds for mining service; ATEX compounds for hazardous area service.
If the application sees oil splash, chemical exposure, or operating temperature above 80°C — the selection is the NM coupling (NBR rubber, excellent oil resistance) or the MH coupling (synthetic rubber, broader chemical compatibility). Avoid natural rubber tyre couplings in oil-contaminated environments.
If the application operates above 6000 rpm — the selection is the disc coupling, diaphragm coupling, or flexible beam coupling depending on size. Elastomeric couplings are speed-limited by the centrifugal stress on the rubber element; metal-elastic couplings are limited only by precision balance.
If the application sees frequent maintenance access — agricultural PTO connections, portable plant, conveyor head drives in difficult locations — the selection is the chain coupling. Master link release without specialist tools; chain replacement through split housing without removing hubs from shafts.
If the application currently has a rigid flange coupling causing bearing wear, and the baseplate cannot be modified for a new coupling envelope — the selection is the HN flange-flexible coupling or the PIN coupling. Both fit the rigid-coupling envelope while providing moderate misalignment compensation.
Get Flexible Coupling Selection Help
HN Flange-Flexible Coupling Construction
The HN coupling hubs are machined from medium-carbon steel forgings. Each hub carries an integral flange with the rated bolt circle and pin-hole pattern; bore tolerance is held to ISO H7 with standard parallel keyway as published in the dimensional documentation. Surface treatment is phosphate-and-paint for standard industrial service or zinc plating for outdoor and marine environments. Larger sizes from HN4 upward can be supplied with taper-bushed bore options for higher torque-transmission reliability.
Pin elements are turned from alloy steel rod with the bushing engagement surface ground to commercial precision tolerance. Standard pins are case-hardened on the bushing engagement surface for wear resistance; high-cycle applications use through-hardened pins for extended fatigue life. Bushings are moulded NBR rubber (standard) or cast polyurethane (heavy-duty) — both bushing types are stocked separately for periodic replacement during scheduled maintenance windows.
HN Coupling Application Field
The HN flange-flexible coupling earns its specification where the application combines a flanged-disc dimensional constraint with a misalignment compensation requirement. The classic example is a motor-to-gearbox connection in heavy industrial duty where the original rigid disc coupling has been wearing out gearbox input bearings within 12 months because the foundation settlement has introduced parallel offset that the rigid coupling cannot accommodate. The HN drops into the same envelope and the bearings last three to five times longer.
Sector Applications for the HN Coupling
Steel mill auxiliary drives where the rolled-product geometry constrains the coupling envelope; mining processing plant where the chute and feeder arrangement leaves no room for an enlarged coupling guard; water treatment plant where the existing flanged interface from the original pump set has fixed the coupling envelope; food processing and chemical plant where the operating environment requires polyurethane bushings rather than the natural-rubber elements of tyre couplings. All these applications routinely specify the HN as the preferred motor-to-gearbox flexible coupling at standard industrial duty.
Why Choose Ever Power Australia
Ever Power Flange Couplings Australia Ltd. carries the complete flexible coupling family from our Sydney warehouse — HN flange-flexible, F-type tyre, jaw spider, tyre spacer, snake spring, chain, disc, diaphragm, beam, and special-purpose configurations. Selection advice from our engineering team is provided free as part of the quotation process; provide the application type, motor power, shaft diameters, and any dimensional constraints and our Sydney technical office returns a confirmed selection within one business day. The ISO 9001 quality management system ensures consistent specification across the entire flexible coupling range.
Ever Power manufacturing facility — ISO 9001 certified, 12,000 m², 108 dedicated coupling machines, 20+ years of production experience.
Every order placed with our Sydney team is backed by full material traceability, dimensional inspection certificates on request, and direct access to the engineers who specified, machined, and packed your coupling. We do not subcontract technical support — when you phone +61 2 9708 3322 during NSW business hours, you reach the people who actually know the product.
Frequently Asked Questions
Quick answers from our Sydney technical team. Contact us for application-specific guidance.
1. When should I specify an HN flange-flexible coupling rather than a tyre coupling? +
2. What is the difference between NBR and polyurethane bushings on the HN coupling? +
3. Can the HN coupling be field-upgraded from a rigid flange coupling? +
4. How quickly can a flexible coupling be supplied from your Sydney warehouse? +
5. Do you provide flexible coupling selection assistance for new installations? +
Request a Quote — Sydney NSW Stock
Tell us your motor power, shaft diameter, and operating environment. Our New South Wales coupling team confirms availability and pricing within one business day, with same-day dispatch on standard sizes from Condell Park.
Ever Power Flange Couplings Australia Ltd. · 27 Harley Crescent, Condell Park NSW 2200 · [email protected]
