30 years of expertise in the manufacture of elastic couplings for industrial power transmission. Over 30 standard models in stock — stainless steel, ATEX, aluminium, carbon versions — plus custom manufacturing to your mechanical requirements.
Flector couplings deliver backlash-free torque transmission while compensating for angular, parallel and axial misalignments. Our range covers standard models (LJ, SW, RFC, RFCT, RRS, RRJ), stainless steel ATEX versions (SSH), lightweight aluminium (SKM, SWA), split hub (SKK), half-shell (SKL), backlash-free (SKT), expandable hub (SKS), conical ring (SKP), as well as the benchmark brands TSCHAN and OLDHAM. Flexible elastic shafts available in steel (SWS), stainless steel (SWE) and carbon (SWC).
Sans jeuINOX ATEXAluminiumAnti-jeuMoyeu fenduBague coniqueTSCHANOLDHAMCustom
Elastic buffer couplings transmit torque while progressively absorbing vibrations and damping shocks. Ideal for applications with frequent start-ups, torque variations and moderate misalignment. Simplified maintenance — the elastomer buffers are replaceable without dismantling the shafts. RN-Flex, RB-Flex (pin & buffer), RC-Flex, RP and RBW range.
Absorption vibrationsDémarrages fréquentsVariations de coupleTampons remplaçablesMaintenance facile
Elastic rim couplings and flexible rings are designed to absorb significant misalignments and dampen shocks in power transmission. Ideal for machines with high cyclic irregularities, combustion engines, compressors and generator sets. TyreFlex (rubber rim), RTP (tyre type), DKP (rigid double-loop solution from RATHI / RINGFEDER), CENTAFLEX A and HEXAFLEX (rubber-metal) solutions.
A few guidelines to orient your choice based on your mechanical constraints.
3Transmissions is the exclusive French distributor of the RATHI Couplings brand and supplies French and European industrial customers with a comprehensive range of more than 30 elastic couplings split into three main families: flector type (LJ, SW, RFC, RFCT, RRS, RRJ, SSH stainless steel, SKM, SKK, SKL, SKT, SKS, SKP, TSCHAN, OLDHAM, SWA, SWS, SWE, SWC), elastic buffer type (RN-Flex, RB-Flex, RC-Flex, RP, RBW) and rim / ring type (TyreFlex, RTP, DKP, CENTAFLEX A, HEXAFLEX). All our models are available 99% in stock within 24/48h with custom machining within 24h on request.
An elastic coupling is an essential mechanical component used to connect two rotating shafts while compensating for misalignments (angular, parallel, axial) and transmitting the driving torque. Unlike rigid couplings, it incorporates an elastomer element (rubber, polyurethane, Hytrel) or a deformable geometry that absorbs shocks, dampens torsional vibrations, extends the service life of downstream bearings and protects driven components from torque peaks.
Selecting an elastic coupling is based on five main technical criteria: nominal and peak torque to be transmitted (in Nm), maximum rotation speed (rpm), bore diameter of the shafts to be connected (mm), expected residual misalignment in service, and operating environment (temperature, humidity, chemical agents, ATEX, food contact). Our engineers will guide you free of charge within 24h towards the solution best suited to your industrial application.
When to choose a flector coupling?
Choose a flector coupling when you need backlash-free transmission, high angular precision, and when misalignments remain moderate. Ideal for servomotors, machine tools, positioning applications and stainless steel/ATEX contexts (SSH model).
Pour les ambiances corrosives ou agroalimentaires : SSH INOX. Pour les applications légères ou hautes vitesses : SKM aluminium. Pour le démontage rapide sans déposer les arbres : SKK moyeu fendu ou SKL demi-coquille.
When to choose a buffer coupling?
Elastic buffer couplings are perfect for applications with frequent start-ups, regular torque variations or a need for vibration damping. They are found on conveyors, pumps, fans and crushers.
Key benefit: the elastomer buffers are replaceable without dismantling the shafts — significant time savings on preventive maintenance. RN-Flex for standard duty, RB-Flex for high torques with pins, RBW for compact versions.
When to choose a rim coupling?
Elastic rim couplings tolerate significant misalignments (angular, parallel, axial) and strongly dampen shocks. Essential for combustion engines, compressors, generator sets and machines with high cyclic irregularity.
TyreFlex and RTP for maximum flexibility; CENTAFLEX A and HEXAFLEX for high torques; DKP RATHI for rigid precision with double loop (RINGFEDER group).
Made-to-orders & usinage spécial
Beyond our catalogue of 30+ standard elastic couplings, we perform all specific modifications in our machining workshops : bores to drawing, drillings, dynamic balancing, surface treatments.
Our consulting engineers assist you in selecting the best solution for your nominal torque, rotation speed, expected misalignment and environment (temperature, ATEX, stainless).
Technical comparison des trois familles
Flector couplings (star element) offer an excellent compromise between torsional stiffness and tolerance to misalignment, with nominal torques from 5 to 10,770 Nm depending on size. Buffer couplings (pins + elastomer) excel at shock absorption and operate in fail-safe mode thanks to residual metal-to-metal contact in the event of buffer failure.
Rim couplings (rubber-fabric tyre) offer the maximum tolerance to misalignment and the best vibration damping capacity — at the cost of lower torsional stiffness. For precision applications (servomotors, encoders), favour flexible elastic shafts SWA / SWS / SWE / SWC with machined body, backlash-free and accurate.
Applications industrielles par secteur
Our elastic couplings have been equipping installations in all sectors for 30 years: food industry (SSH stainless steel and SWE stainless steel versions FDA-certifiable, CIP/SIP compatible), chemical and pharmaceutical industries (ATEX explosive zones, anti-corrosion), water treatment and wastewater plants, cement plants and quarries (reinforced RTP for crushers and grinders), paper mills and printing plants.
Also present in the navy and marine sector (CENTAFLEX A for onboard generator sets), SNCF railway, nuclear and defence (DKP RATHI 100% metallic, without sensitive elastomer), API 610 / 671 process pumps (RRS spacer model for back pull-out), compressors, industrial fans, conveyors, CNC machine tools and high-dynamic servomotors.
Why 3Transmissions
Performance at the service of your productivity
30+
Elastic models
99%
Dispo within 24h/48h
24h/48h
Livraison express
30 ans
Expertise terrain
A custom coupling? Urgent need? Let's talk.
Our engineers support you from model selection (flector, buffer, rim) through to delivery on site. Free quote within 24h, custom manufacturing available, large stock for express delivery.
