Beschreibung
Ever-Power | PTO Drive Shafts
RAS Overrunning Clutch
Precision-Engineered Clutch Protection for Agricultural & Industrial PTO Drivelines — UK Supply
The RAS overrunning clutch is a high-precision mechanical component engineered to protect PTO drive shafts and connected machinery from the damaging effects of sudden torque reversal, overloading, and coasting conditions. Widely deployed across UK farming operations, groundskeeping equipment, and light industrial machinery, this overrunning clutch acts as a one-way power transmission device — allowing the driven shaft to rotate freely when it exceeds the driving shaft’s speed, preventing shock loads and drivetrain stress that can destroy gearboxes, universal joints, and implement housings.
At Ever-Power, our RAS overrunning clutch series is manufactured to the highest tolerances using premium-grade steel alloys and precision spline machining, ensuring consistent engagement, smooth freewheeling, and outstanding durability across tens of thousands of operating cycles. Whether you run a mixed arable farm in Yorkshire, manage a turf maintenance fleet in Surrey, or procure PTO components for agricultural dealers across England and Scotland, the RAS clutch delivers the reliability you demand from a component that protects your entire driveline investment.
Why the RAS Overrunning Clutch Outperforms the Rest
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Instant Torque Disengagement
The RAS overrunning clutch responds in milliseconds to speed differentials between the input and output shaft, completely eliminating backlash torque before it can damage implement gearboxes or PTO shaft tubes. This protects your machinery investment during sudden stops, direction changes, and coasting sequences.
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Heavy-Duty Steel Construction
Housing, hub, and prong components are precision-machined from high-strength alloy steel, surface-hardened for wear resistance and long service life even in muddy, high-vibration agricultural environments. The splined shaft interface is produced to DIN standards for guaranteed tractor compatibility across all UK-market tractor brands.
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High Torque Capacity — Up to 3500 Nm
With the RAS2 series rated at 3500 Nm maximum torque and the RAS1 handling up to 2400 Nm, these clutches are sized for real-world PTO demand. Whether you’re running a heavy flail mower, a twin-rotor tedder, or a slurry tanker PTO pump, there’s an RAS series clutch built for the load.
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Easy Maintenance & Serviceability
The modular component design — circlip, retaining washer, push pin kit, hub, prong kit, housing with splined shaft, and grease nipple — allows field-level maintenance without specialist tooling. The integrated grease nipple allows scheduled lubrication without disassembly, dramatically extending service intervals in demanding UK field conditions.
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Universal 1 3/8″ Z6 Spline Compatibility
Both RAS1 and RAS2 variants use the industry-standard 1 3/8″ Z6 spline profile on both female and male interfaces, ensuring bolt-on compatibility with virtually every tractor PTO shaft sold across the UK market, including John Deere, Massey Ferguson, New Holland, Case IH, and Fendt platforms.
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Custom Supply for UK Agricultural Dealers
Ever-Power supports agricultural machinery distributors, OEM implement builders, and parts suppliers across England, Scotland, Wales, and Northern Ireland with flexible order quantities, custom spline options, and branded packaging. Our UK B2B supply programme includes competitive pricing and fast despatch direct from factory-level inventory.
Technical Specifications
All dimensions in millimetres. Torque ratings are maximum values under standard operating conditions.
▶ Performance & Dimensional Data
| Serie | Max Torque (Nm) | Spline (Female) | Spline (Male) | A (mm) | B (mm) | C (mm) |
|---|---|---|---|---|---|---|
| RAS1 | 2400 | 1 3/8″Z6 | 1 3/8″Z6 | 142 | 21 | 38 |
| Serie | Max Torque (Nm) | Spline (Female) | Spline (Male) | A (mm) | B (mm) | C (mm) |
|---|---|---|---|---|---|---|
| RAS2 | 3500 | 1 3/8″Z6 | 1 3/8″Z6 | 161 | 21 | 38 |
▶ Component Parts List
| No. | Beschreibung | Anmerkungen |
|---|---|---|
| 1 | Circlip | |
| 2 | Retaining washer | |
| 3 | Push pin kit | |
| 4 | Hub | |
| 5 | Prong kit | Qty. = 3 |
| 6 | Housing with splined shaft | |
| 7 | Grease nipple |
How It Works, What It’s Made Of, and Where It’s Used
⚙ Operating Principle
The RAS overrunning clutch uses a prong-and-ratchet mechanism housed inside a precision steel enclosure. Three hardened prong elements engage during normal power transmission, locking the input and output shafts together to transmit full engine torque to the implement. The moment the output shaft (implement-side) begins to rotate faster than the input shaft — as happens when a heavy flywheel or rotor continues spinning after the tractor’s throttle is cut — the prongs retract and the housing freewheels silently and freely. This prevents destructive reverse torque from travelling back up the PTO shaft to the tractor’s gearbox.
🔧 Materials & Surface Treatment
The housing with integrated splined shaft is forged from medium-carbon alloy steel and CNC-machined to tight tolerances, then induction hardened on all friction and wear surfaces to 58–62 HRC. The hub and prong kit components are precision-cast from ductile iron with a phosphate surface treatment for corrosion resistance during storage and transit. Circlip and retaining washer elements are spring steel, hardened and tempered to maintain secure retention throughout the full torque range. Every unit receives a manganese phosphate coating before final assembly, offering baseline corrosion protection suitable for UK outdoor agricultural use.
🏞 Application Scenarios
The RAS overrunning clutch is the right choice wherever high-inertia PTO implements are used. In UK arable and grassland farming this includes flail mowers, rotary cutters, grass tedders, silage choppers, and PTO-driven slurry spreaders. In horticulture and turf management it suits large ride-on mowers, aerators, and scarifiers. Light industrial uses include log splitters, irrigation pumps, and mobile power generation sets where PTO-driven generators must be protected from reverse torque surges during load shedding events. Anywhere a driven machine carries significant rotational inertia past the point of tractor power cutoff, the RAS overrunning clutch prevents drivetrain damage.
Our PTO Drive Shaft Product Range
The RAS overrunning clutch is designed to complement the full Ever-Power PTO drive shaft family. Each series is optimised for a specific duty cycle and power requirement.
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PTO Drive Shaft G Series
The G Series is the go-to general-purpose PTO shaft for standard agricultural implements. Robust cross joint design, wide torque range, and proven performance across a vast range of UK farm machinery.
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PTO Drive Shaft S Series
The S Series features heavy-duty shielding and reinforced tube profiles for demanding duty cycles. Ideal for high-torque applications including large bale presses, muck spreaders, and contractor-grade equipment.
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PTO Drive Shaft L Series
The L Series is engineered for longer working lengths and implements requiring extra telescopic travel. A popular choice for front-mounted and wide-angle PTO configurations on UK mixed farming operations.
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PTO Drive Shaft T Series
The T Series delivers top-tier torque capacity and is optimised for tractor horsepower above 120HP. Frequently specified for high-output contractor machinery, large-scale silage equipment, and specialised harvesting implements.
Factory Capability & Custom Overrunning Clutch Supply
Ever-Power’s manufacturing facility operates a fully integrated production line for PTO overrunning clutches, with in-house CNC machining, heat treatment, assembly, and quality inspection. Our engineering team has over 18 years of experience in PTO drivetrain component design, and we routinely work directly with UK agricultural machinery OEMs, implement dealers, and parts wholesalers to deliver custom solutions that off-the-shelf products cannot provide.
Our customisation capabilities for the RAS overrunning clutch include non-standard spline profiles, modified A/B/C dimensional envelopes, alternative surface coatings (hot-dip zinc, epoxy powder coat), private label or OEM branding, and custom packaging for retail or trade counter distribution. Minimum order quantities are negotiable for established UK distributors. We manufacture to customer-supplied drawings as well as our own catalogue designs, and every custom batch is backed by full dimensional inspection reports.
Ever-Power Manufacturing Floor
Customer Success: Yorkshire Grassland Contractor, UK
Background: Harrogate Grassland Services Ltd. is a contractor operating a fleet of twelve high-output flail mowers and rotary tedders across the North Yorkshire Dales and surrounding farmland. In 2023 the company was experiencing repeated PTO shaft failure on three of its Kuhn flail mower units — all linked to reverse torque shock when heavy rotors continued spinning after PTO disengagement during end-of-field headland turns.
Solution: Ever-Power supplied RAS2 overrunning clutches as direct retrofits onto the affected machines. The 3500 Nm rated RAS2 was specified to comfortably handle the rotor inertia on 1.8-metre wide flail units with no margin compromise. Installation was completed by the company’s own mechanic in under an hour per machine using standard agricultural workshop tooling.
Outcome: In the twelve months following fitment, zero PTO shaft failures were recorded across the three treated machines — compared to a combined four failures in the previous season. The fleet manager reported measurable fuel savings from smoother PTO engagement cycles and estimated total repair and downtime cost savings of over £6,200 across the season. All three machines have since been re-ordered for the following year’s contract fleet expansion.
What UK Customers Say
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“We’ve fitted RAS2 clutches to our full mower fleet after the first one transformed reliability on our worst machine. Twelve months on, not a single PTO shaft issue. The build quality is noticeably better than what we were sourcing from our previous UK supplier.”
James Thornton, Fleet Manager
Harrogate Grassland Services Ltd., North Yorkshire
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“As an agricultural parts distributor covering Scotland, we’ve been importing directly from Ever-Power for two seasons. Lead times are predictable, documentation is complete, and we’ve had zero warranty claims on the overrunning clutch line. Our customers appreciate the consistent quality.”
Moira Campbell, Procurement Director
ScotAgri Parts Ltd., Stirling, Scotland
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“We specified the RAS1 clutch across our golf course maintenance fleet in Surrey — fourteen machines. The freewheeling action is smooth, installation is simple, and the grease nipple makes servicing quick. A very well-engineered component at a price point that makes fleet-wide fitment genuinely practical.”
Richard Blake, Head Groundsman
Surrey Turf Management Ltd., Surrey
Häufig gestellte Fragen
What is the difference between the RAS1 and RAS2 overrunning clutch series, and how do I know which one I need for my UK farm machinery?
The RAS1 is rated to 2400 Nm maximum torque and has an overall length (dimension A) of 142 mm, making it suitable for medium-duty implements such as standard rotary mowers, tedders, and light cultivators. The RAS2 handles up to 3500 Nm and measures 161 mm on the A dimension, suited to heavier implements including contractor-grade flail mowers, large bale presses, and high-output rotary cutters. If you’re unsure which series is correct for your application, send us your implement’s PTO input shaft torque rating and we’ll confirm the right specification.
Where can I get a price or quote for RAS overrunning clutches supplied to agricultural dealers or distributors across England, Scotland, or Wales?
You can request a trade price or formal quotation by emailing our sales team at [email protected]. Please include your required series (RAS1/RAS2), order quantity, and preferred delivery address. We serve UK agricultural parts distributors, OEM implement manufacturers, and machinery dealers with competitive ex-works pricing and responsive lead times.
How does an overrunning clutch protect my tractor’s PTO gearbox during flail mower operation in the UK?
When you disengage the tractor’s PTO at the headland, the flail mower’s rotor continues spinning under its own inertia — sometimes for 30 seconds or more on heavy units. Without an overrunning clutch, this spinning mass drives torque back up the PTO shaft and into the tractor’s gearbox, potentially breaking shaft pins, damaging cross joints, or cracking gearbox casings. The RAS overrunning clutch disconnects the load from the drive shaft the moment the implement-side speed exceeds the tractor-side speed, absorbing this energy safely within the clutch housing.
Which tractor brands used on UK farms are compatible with the 1 3/8″ Z6 spline on the RAS overrunning clutch?
The 1 3/8″ Z6 spline profile is the predominant standard across virtually all tractors sold in the UK market, including John Deere, Massey Ferguson, New Holland, Case IH, Fendt, Claas, Deutz-Fahr, Valtra, and JCB Fastrac models. Both the female and male spline on the RAS1 and RAS2 use this specification, making these clutches a direct fit for the vast majority of PTO driveline configurations seen on UK farms.
How often should I service the RAS overrunning clutch on my grassland machinery, and what does the maintenance process involve?
We recommend greasing the RAS overrunning clutch via the integrated grease nipple every 50 operating hours or at the start of each seasonal campaign — whichever comes first. Use a lithium-based EP2 grease and apply 2–3 strokes of a hand grease gun until fresh grease appears at the seals. The modular component design means that worn prong kits or circlips can be replaced individually without replacing the entire unit, keeping maintenance costs low across multi-year service life.
Can Ever-Power supply custom RAS overrunning clutches with non-standard spline sizes or modified dimensions for OEM implement manufacturers in the UK?
Yes — Ever-Power’s factory engineering team works regularly with UK implement OEMs to produce custom overrunning clutch variants outside our standard catalogue. This includes alternative spline profiles, custom A/B/C dimensions, modified torque ratings, alternative surface treatments, and OEM branding. Please contact our sales team at [email protected] with your technical drawing or specification sheet and we’ll provide a detailed quotation within two working days.
Source RAS Overrunning Clutches Direct from Factory
Whether you need a single replacement clutch or a bulk supply contract for UK distribution, our team is ready to help. Contact us for pricing, technical datasheets, and lead times.
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