A disc coupling connects two hubs through flexible packs of thin stainless steel discs, bolted alternately to each side, so torque passes through the discs while angular and axial misalignment is taken up by flexing them. There is nothing to lubricate and no clearance to wear, so the coupling has zero backlash and is inherently self-centering. The category is the Kop-Flex KD line, sized 053 through 905, in close-coupled styles for shafts that meet, spacer styles for pumps and other drives with a gap between shaft ends, and single-flex and floating-shaft styles, together with Jaure LAMIDISC disc pack kits.
Also known as: disc coupling, disc pack couplings, flexible disc couplings, kd couplings, lamidisc couplings
Series in this category
Related guides: Coupling types compared, Cross-reference help
| Specification | What it means |
|---|---|
| Coupling size | The KD size number, 053 through 905. It fixes the torque rating, the bore range and the hub dimensions. |
| Style | KD1, KD10, KD11, KD2, KD20, KD21, KD4, KD41 or KD42, which sets close-coupled, spacer, single-flex or floating-shaft construction. |
| Disc pack | MT medium torque, HT high torque, HS high torque semi-unitized, or CT cooling tower, each matched to particular KD styles. |
| Configuration | The pair of hubs a complete coupling ships with: standard, long or jumbo on each side. |
| Torque rating | Continuous torque in lb-in or lb-ft for the size and disc pack, checked against selection torque. |
| Stock C dimension | The shaft separation a spacer coupling is built for, from 3.5 to 14 inches on stock units. |
| Maximum speed, balanced | The rpm limit for a dynamically balanced assembly. Floating-shaft styles also have to be checked for lateral critical speed. |
No. The flexible members are stainless steel discs, so there is no grease, no seal and no cover to maintain, and the coupling has no backlash. That, along with corrosion resistance and good balance, is why the manufacturer lists disc couplings for pumps, compressors, generators, cooling towers and paper machines.
On the KD1 and KD10 close-coupled styles, yes: the unitized disc pack is replaced in place. On the KD2, KD20 and KD21 spacer styles the whole center section drops out between the hubs. Most packs are unitized with self-locking nuts, which keeps loose parts to a minimum during the change.
A disc coupling accommodates both angular and axial misalignment by flexing its disc packs, and each size lists an axial capacity. The manufacturer's own comparison notes limited misalignment capacity as the trade-off against a gear or elastomeric coupling, so shafts should be aligned carefully at installation.
Yes. The KD33 uses CT disc packs with stainless steel components and a stainless or composite tube for the very long shaft separations of cooling tower drives, in sizes 153 to 303 with bores from 0.50 to 4.50 inch, and is non-lubricated like the rest of the line.
