The RP-A Standard Jaw Flexible Coupling is a compact, low-inertia flexible coupling manufactured from engineering-grade polyurethane elastomers. Designed for cushioning, vibration damping, and wear resistance, it operates across a temperature range of −35 °C to +800 °C and requires zero maintenance. Maximum torque 18,650 N·m; maximum bore Φ200 mm.
The RP-A Standard Jaw Flexible Coupling is the workhorse of the RP jaw coupling range, combining a compact envelope with exceptional shock absorption. Its engineering-plastic elastomeric spider is constrained by the claw geometry on both hubs, preventing the internal deformation and centrifugal expansion that can occur in less refined designs. The large concave-convex claw profile distributes tooth-face pressure uniformly, so the involute teeth resist wear and maintain dimensional integrity even after sustained overloads. Axial plug-in assembly means no special tooling is required during installation — the two hubs simply slide onto their respective shafts and the spider drops into place.
Two elastomer hardness grades are available: 92 ShA for standard damping and 98 ShA for elevated torque transmission — the stiffer grade increases nominal torque capacity by approximately 70 %. Both grades are compatible with the same hub hardware, giving engineers a straightforward upgrade path without redesigning the coupling interface. Bore and keyway dimensions can be machined to customer specification across the full model range, from the smallest TS14A (bore 6–16 mm) up to TS180A (bore 85–200 mm).
| Model | Torque (N·m) | Speed (rpm) | Bore d (mm) | L (mm) | D (mm) | E (mm) |
|---|---|---|---|---|---|---|
| RP14A | 7.5 | 19000 | 6–16 | 11 | 35 | 13 |
| RP19A | 10 | 14000 | 6–19 | 25 | 66 | 16 |
| RP24A | 35 | 10600 | 8–24 | 30 | 78 | 18 |
| RP28A | 95 | 8500 | 8–28 | 35 | 90 | 20 |
| RP38A | 190 | 9500 | 10–38 | 45 | 114 | 24 |
| RP42A | 265 | 8000 | 10–42 | 50 | 126 | 26 |
| RP48A | 310 | 7100 | 10–48 | 56 | 140 | 28 |
| RP55A | 410 | 6300 | 15–55 | 65 | 160 | 30 |
| RP65A | 625 | 5600 | 15–65 | 75 | 185 | 35 |
| RP75A | 1280 | 4750 | 20–75 | 85 | 210 | 40 |
| RP90A | 2400 | 3750 | 30–90 | 100 | 245 | 45 |
| RP100A | 3300 | 3350 | 30–115 | 110 | 270 | 50 |
| RP110A | 4800 | 3000 | 40–125 | 120 | 295 | 55 |
| RP125A | 6650 | 2650 | 40–145 | 140 | 340 | 60 |
| RP140A | 8600 | 2360 | 40–160 | 155 | 375 | 65 |
| RP160A | 12800 | 2000 | 60–180 | 175 | 425 | 75 |
| RP180A | 18650 | 1800 | 85–200 | 195 | 475 | 85 |
The RP-A is a versatile coupling suited to a wide spectrum of industrial drive trains. Its compact geometry makes it a first choice wherever installation space is restricted, while the maintenance-free elastomeric spider lowers lifetime operating costs significantly compared with gear or chain couplings. Representative industries include:
For applications requiring greater misalignment compensation, consider the RP-S double-elastomer jaw coupling. For flange-to-shaft connections in heavy plant, the RP-F flange jaw coupling offers additional bolt-circle mounting flexibility.
🇩🇪 Netherlands — Food & Beverage Processing
A bottling-line manufacturer in Breda replaced a rubber jaw coupling on their filling-machine servo axis with an RP-A unit. The lower inertia improved indexing repeatability from ±0.3° to ±0.08°, allowing line speed to increase by 12 % without additional servo tuning.
★★★★★
"The plug-in assembly took under five minutes per coupling. Maintenance intervals have been extended considerably." — Plant Engineer
🇩🇪 Germany — Industrial Pump OEM
A centrifugal pump manufacturer near Munich standardised on the RP-A across their 22 kW to 160 kW product range. The 98 ShA elastomer option was selected for high-power models, eliminating a premature spider-wear issue that had affected the previous coupling supplier.
★★★★★
"Consistent bore tolerances across the entire range reduced our assembly time noticeably." — Procurement Manager
🇬🇧 United Kingdom — Conveyor Systems Integrator
A system integrator in the West Midlands specified RP-A couplings throughout a large distribution-centre conveyor project. The zero-maintenance requirement was a primary selection criterion; after 18 months in continuous three-shift operation no elastomer replacements have been needed.
★★★★☆
"Good dimensional accuracy and competitive pricing on volume orders." — Project Buyer
92 ShA is the standard softer grade that delivers better shock absorption and vibration damping, making it the preferred choice for most general drive applications. 98 ShA is the stiffer high-torque grade — using 98 ShA increases the nominal torque capacity by approximately 70 % compared with the table values, making it suitable for heavy-duty or torsionally stiff drive trains. Both grades fit the same hub hardware.
The polyurethane elastomeric spider resists moisture, oils, and mild cleaning agents, making RP-A couplings broadly compatible with food and beverage processing environments. For direct food-contact applications, verify the specific elastomer compound against applicable hygiene standards in your region.
Calculate the design torque as: Design Torque = Rated Motor Torque × Service Factor. Service factors range from 1.5 for smooth loads up to 2.5 or higher for heavy shock loads. Select the smallest RP-A model whose nominal torque exceeds the design torque, then verify the bore range covers both shaft diameters. Use the 98 ShA elastomer if an intermediate size would suffice with the upgraded grade.
Yes — this is one of the primary maintenance advantages of the jaw coupling design. Provided sufficient axial clearance exists between the two hub faces, the spider can be slid out radially or axially and a new element fitted without moving either hub along the shaft. Always power down the drive completely before carrying out any maintenance.
The RP-A tolerates small angular misalignment (typically up to 1°) and small parallel offset through the elastic deformation of the polyurethane spider. It is not designed to compensate large or systematic installation misalignment; always align shafts as accurately as possible to maximise elastomer service life. If your application involves larger angular or parallel misalignment, the RP-S double-elastomer model provides significantly greater compensation capacity.
RP is an established supplier to OEM manufacturers, industrial distributors, and mechanical engineering contractors across Europe and beyond. Whether you require a small trial batch or a long-term supply arrangement, our technical and commercial teams are ready to discuss your requirements. Custom bore machining, special elastomer compounds, and non-standard sleeve configurations are all available.
Browse the full coupling range or explore the complete jaw coupling series for alternative models.
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