Description
The SWC-DH is the Short Flex configuration of the welded-yoke universal coupling family — designed for installations where the available space between gearbox and driven machine is restricted. Same 22-degree flex angle and same torque rating as the SWC-BH and SWC-CH variants of equivalent gyration diameter, but with a substantially shorter intermediate shaft. This makes the SWC-DH the engineering choice for finishing mill stands, compact machine tool drives, and underground mining equipment where tight installation envelopes demand a compact heavy duty shaft coupling.
SWC-DH Specifications and Dimensional Range
The SWC-DH range covers gyration diameters from 100 mm to 390 mm, with the same nominal torque ratings as the SWC-BH equivalent sizes. The Lmin minimum installed length is approximately 40 percent of the SWC-BH equivalent — providing maximum compactness in space-constrained installations. The trunnion cross, bearings, and spline geometry remain interchangeable with the Standard and Long Flex variants of the same gyration diameter, simplifying spare parts inventory across the SWC welding-type range.
| Model | Gyration Ø D (mm) | Nominal Torque Tn (kN·m) | Fatigue Tn Tf (kN·m) | Flex Angle β (°) | Bore D₂ (mm) | Lmin (mm) |
|---|---|---|---|---|---|---|
| SWC100DH | 100 | 1.0 | 0.5 | ≤22° | 20–44 | 210 |
| SWC150DH | 150 | 4.0 | 2.0 | ≤22° | 30–65 | 260 |
| SWC200DH | 200 | 15 | 7.5 | ≤22° | 40–95 | 300 |
| SWC250DH | 250 | 32 | 16 | ≤22° | 55–115 | 350 |
| SWC285DH | 285 | 63 | 31.5 | ≤22° | 75–130 | 380 |
| SWC315DH | 315 | 100 | 50 | ≤22° | 85–150 | 420 |
| SWC390DH | 390 | 200 | 100 | ≤22° | 100–175 | 475 |
The compact installed length comes at the cost of reduced axial travel — typically 30 to 40 mm of telescoping range versus 80 to 100 mm on the Standard Flex equivalent. For installations with significant thermal growth or foundation movement, verify the operating axial range fits within the Short Flex travel envelope before specifying.
SWC-DH Short Flex Welding Type Universal Coupling – compact intermediate shaft for tight installation envelopes. Ever Power Flange Couplings Australia Ltd.
What Distinguishes the SWC-DH from Other Universal Joint Types
The SWC-DH solves the compact-installation problem that arises when the SWC-BH Standard Flex variant cannot fit within the available space between driver and driven machine. Common cases include finishing mill stand spindles where the work roll is positioned close to the gearbox output, machine tool spindle drives where overall machine footprint dictates compact subsystems, and underground mining equipment where machine envelope is restricted by tunnel geometry.
Functionally, the SWC-DH delivers identical torque transmission to the SWC-BH at any given flex angle. The reduced intermediate shaft length means less polar moment of inertia, which actually improves start-up acceleration response in dynamic drive applications. The shorter spline travel range is the only operational limitation — installations with substantial axial thermal growth may require the Standard Flex variant despite the larger envelope footprint.
Trade-Off Between Length and Travel Range
Selecting the Short Flex variant trades axial travel range for installation compactness. Before specifying, calculate the maximum axial movement expected during operation — thermal growth of the driver and driven machine, foundation settlement, and load-induced shaft movement. The total expected axial movement must sit within the SWC-DH travel envelope with safety headroom. If your calculated movement approaches or exceeds the Short Flex travel range, specify the Standard Flex (SWC-BH) variant.
Construction and Material Specification
Material specification is identical to SWC-BH and SWC-CH: 35CrMo alloy steel forging, full quench-and-temper heat treatment, induction-hardened trunnion journals and spline teeth to HRC 58-64. The trunnion cross, needle bearings, and spline geometry match the equivalent Standard Flex variant — only the intermediate shaft length differs between the variants.
Sealed needle roller bearings are pre-lubricated at assembly for the design service life. The yoke-to-shaft weld preparation follows the same procedure as SWC-BH. The compact intermediate shaft simplifies field welding because the assembly is lighter and easier to handle during installation positioning.
Lmin approximately 40 percent of SWC-BH equivalent. Designed for tight installation envelopes including finishing mill stands, machine tool spindles, and underground mining equipment where envelope is restricted.
Same welded-yoke torsional stiffness as Standard and Long Flex variants. Eliminates bolt-circle tolerance chain that limits flanged hub stiffness on high-frequency reverse-load applications.
Identical material and heat treatment to SWC-BH and SWC-CH. Trunnion cross, bearings, and spline parts interchangeable across the full SWC welding-type range at any given gyration diameter.
Pre-lubricated at assembly. Lifetime sealing eliminates the periodic re-greasing requirement of older universal joint designs.
Same flex angle rating as Standard and Long Flex variants of equivalent gyration diameter. Substantial headroom above typical operating angles.
Full material traceability and dimensional inspection records available on request.
Industrial Applications Across Heavy Industry
SWC-DH applications cluster around installations where compact envelope is a primary design constraint. Finishing mill stands, machine tool main spindles, and underground equipment drivelines all benefit from the reduced installed length. The Short Flex variant is also specified on retrofit projects where existing equipment cannot accommodate a Standard Flex installation length.
Finishing Mill Stand Spindles
Plate and bar finishing mill stands operate with the work roll positioned close to the drive gearbox output to minimise overall mill footprint. The compact spindle length of the SWC-DH variant fits within these envelopes while delivering full nominal torque rating. The 22-degree flex angle accommodates the work roll height adjustments during pass-line changes without excessive flex margin loss.
Compact Machine Tool and Mining Drives
CNC machine tool main spindle drives, particularly on horizontal boring mills and large machining centres, specify Short Flex universal couplings between the motor and the spindle gearbox. Underground continuous miner drives and tunnel boring machine drivelines similarly use the compact variant where envelope is restricted by tunnel geometry. The torque rating supports both applications without compromise compared to Standard Flex equivalents.
SWC-DH compact yoke and shaft assembly – designed for finishing mill stands and machine tool drives where envelope is restricted.
Selecting the Correct SWC-DH Size for Your Drive
Selection between SWC-DH and SWC-BH depends on the available installation envelope and the expected operational axial movement. If the available space between driver and driven shafts is less than the SWC-BH Lmin for the required size class, the Short Flex variant is mandatory. If space is adequate for either, calculate the expected operational axial movement and verify it sits comfortably within the Short Flex travel envelope before committing.
Where axial movement exceeds the Short Flex envelope but space is too tight for Standard Flex, consider operating two SWC-DH variants in series with an intermediate support bearing — this configuration is common on certain rolling mill installations and is supported by our Sydney engineering team for specification work.
Installation, Operation, and Maintenance Best Practice
Installation follows the SWC-BH workflow with one operational benefit: the lighter compact assembly is easier to position and weld in confined installation spaces. The same qualified-welder requirement and same weld procedure specification apply to SWC-DH as to the longer flex variants.
Before commencing installation, confirm the available envelope matches or exceeds the SWC-DH installed dimension. Verify clearance to adjacent equipment that could be damaged by weld heat.
Both shaft ends machined square, free of burrs, prepared for welding. Verify material weldability documentation. Pre-heat per the supplied weld procedure if required.
Slide each yoke onto its shaft to the design position. Apply tack welds to hold position. Verify trunnion cross rotates smoothly by hand before completing the full weld.
Verify the compact splined intermediate shaft moves through its full axial travel range without binding. The reduced travel range demands careful attention to installed-length verification before completing the weld.
Run full circumferential welds in multiple passes per the supplied procedure. Allow controlled cooling. Post-weld heat treatment per engineering specification if required.
Run at progressively increasing speed to full operating speed. Monitor vibration, temperature, and axial position for first 50 hours. Inspect bearings and seals at first scheduled maintenance.
OEM Cross-Reference and Order Specification
Cross-reference is available for Voith Turbo compact cardan shafts, Rexnord short-flex universal joint couplings, and SKF compact industrial couplings. Provide OEM model code, gyration diameter, nominal torque, installed length, and connection method. We confirm the SWC-DH equivalent and any dimensional differences before order confirmation.
Where the original equipment manufacturer’s compact universal coupling is no longer available, the SWC-DH provides the most direct functional replacement option. Our Sydney engineering team handles the dimensional verification and any necessary minor adjustments without additional consulting fees.
Why Choose Ever Power Australia
Ever Power Flange Couplings Australia Ltd. stocks the commonly specified SWC-DH sizes at our Condell Park warehouse for same-day dispatch on stock-confirmed orders. The compact Short Flex variant is particularly important for retrofit applications where the original SWC-DH equivalent is no longer available from the OEM — our cross-reference work identifies the appropriate Ever Power match and handles any minor dimensional adjustments without additional engineering charges.
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 is the SWC-DH the correct choice over SWC-BH or SWC-CH? +
2. Is the torque rating of SWC-DH the same as SWC-BH for the same gyration diameter? +
3. What is the axial travel range of the SWC-DH telescoping shaft? +
4. Can I install two SWC-DH variants in series for additional axial range? +
5. How quickly can I receive an SWC-DH from your Sydney warehouse? +
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]
