Pin & Buffer Type Couplings
Danum Couplings supplies a diverse range of pin and buffer couplings for demanding industrial drives, built to protect equipment, reduce shock loads, and simplify maintenance. These are ideal for applications with misalignment and shock loading. We offer 24/7 support and fast supply to sites across the UK.
Key Components
This coupling is a modified form of a standard flange coupling, replacing rigid bolts with flexible pin-and-buffer assemblies:
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Two Flanges (Hubs): Typically made of cast iron or steel, these are fixed to the ends of the driving and driven shafts.
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Steel Pins: Bolts that are rigidly fastened to one flange with nuts but remain loose in the other flange's holes.
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Flexible Buffers (Bushes): Elastomeric sleeves—usually made of neoprene, urethane, or polyurethane that are fitted over the pins. These buffers sit inside the holes of the second flange to provide a cushioning effect
Working Principle
Torque Transmission: As the driving shaft rotates, it moves the pins fastened to its flange.
Cushioning: The pins transmit this force to the driven flange through the flexible buffers.
Misalignment Handling: The "barrel" shape or flexibility of the buffers allows the coupling to accommodate up to 0.5 degrees of angular misalignment, as well as minor parallel and axial deviations.
Fail-Safe Operation: If the elastomer buffers wear out or fail, the pins can still drive the other flange (metal-on-metal), allowing the machine to be shut down safely rather than failing instantly.
Pin & Buffer Coupling Brands
Renold Pinflex
The Renold Pinflex is a robust, heavy-duty pin-and-buffer coupling designed for general industrial applications requiring reliable torque transmission under arduous conditions. It is particularly valued for its fail-safe operation and its ability to handle heavy shock loads, making it a standard choice for safety-critical systems like escalator drives and fire pumps.
Key Specifications & Performance
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Maximum Power: Up to 340Kw at 100Rpm.
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Maximum Torque: 32,500Nm.
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Maximum Speed: Up to 6,800Rpm (varies by size).
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Maximum Shaft Size: Up to 260mm.
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Temperature Range: Standard polyurethane buffers operate between -40°C and +80°C; specialized Hytrel buffers can withstand up to +120°C.
Features and Benefits
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Torsional Flexibility: The urethane buffers provide shock absorption, which dampens impact loads and extends the service life of connected machinery.
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Compact Strength: Features steel half-bodies that are more compact and lighter than traditional cast iron designs, while allowing for larger bore sizes.
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Ease of Maintenance: Designed with a minimum number of wearing parts. Buffers can be replaced without moving the coupled shafts, significantly reducing downtime.
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Versatile Mounting: Available in various configurations, including taper bore versions for easy maintenance and modular designs for brakedrum or shear pin applications.
Renold Crownpin
The Renold Crownpin is a heavy-duty pin and bush coupling designed for arduous industrial conditions. It features cast iron half-bodies and neoprene rubber buffers, making it torsionally flexible and capable of absorbing significant shock loads.
Industrial Applications
This coupling is widely used across various heavy industrial sectors:
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Material Handling: Conveyors, cranes, and lifts.
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Fluid Processing: Pumps and industrial washers.
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Air Movement: Fans and large blowers.
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Infrastructure & Leisure: Screens and leisure rides.
KTR Revolex
The KTR REVOLEX is a torsionally flexible, fail-safe pin and bush coupling designed specifically for high-torque applications and drives subject to heavy shocks. It is widely used in heavy-duty industries such as pump manufacturing, conveyor technology, and general mechanical engineering.
Key Features & Benefits
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Fail-Safe Design: Transmits torque reliably while dampening vibrations and shocks.
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Compact & Axial Plug-in: Features a short overall length and can be plugged in axially for easy assembly.
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Maintenance-Free: The coupling components are designed to require no maintenance during operation.
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Easy Disassembly: Equipped with pins that can often be dismantled hydraulically, allowing for smooth removal of elastomer rings without special tools or moving the drive/driven components.
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High Torque Capacity: Standard models can handle torques from approximately 3,800 Nm up to 1,220,000 Nm.
Common Product Variants
KTR offers several specialized versions of the REVOLEX coupling to suit specific technical requirements:
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REVOLEX KX-D (Cast Iron)
The standard, cost-effective version suitable for circumferential speeds up to 35 m/s.
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REVOLEX KX-D (Steel)
Designed for high-speed performance (up to 60 m/s), ideal for applications like directly driven industrial fans.
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REVOLEX KX-D SB (with Brake Disk)
A version that incorporates a brake disk for use as either a holding or service brake.
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REVOLEX KX-D Split
Features hubs split into halves to allow for assembly and disassembly without moving heavy machinery like motors or pumps.
Bibby EFlex
The Bibby Eflex (often referred to as El-flex) is a high-performance pin and bush flexible coupling manufactured by Bibby Turboflex. It is designed to transmit high torque while providing significant torsional flexibility and accommodating various shaft misalignments.
Key Features and Specifications
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Torque Capacity: Capable of transmitting up to 96 kNm (548,000 in-lbs).
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Misalignment Accommodation: Accepts parallel, angular, and axial misalignment, protecting connected machinery from stress.
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Flexible Elements: Uses close-fitting elements with 80 or 90 Shore hardness rubber to absorb shock and dampen vibrations.
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Maintenance: Requires no lubrication, making it suitable for clean or hostile environments.
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Versatility: Can be used in both vertical and horizontal operations and is available with either parallel or taper bore options.
Primary Applications
These couplings are frequently used in demanding industrial settings such as:
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Pumps and Compressors: Protecting drive systems from torsional vibrations.
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Fans and Blowers: Ideal for applications with fluctuating loads.
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Conveyors and Gearboxes: Ensuring smooth power transmission in material handling.
Dynamic Shock Damping
Expertly tuned for torsional flexibility, these units neutralize peak torque and industrial vibrations to prevent catastrophic component fatigue and failure.
Versatile Alignment
Engineered to tolerate significant radial, angular, and axial variations, providing a robust interface between shafts even under difficult operating conditions.
Streamlined Service
The design facilitates quick buffer inspection and replacement in situ, drastically reducing downtime by eliminating the need to dismantle the entire drive.
Specialist Hub: Danum Couplings Expert Center
As a specialist coupling centre, we offer unrivalled choice including Renold Pinflex, Renold Crownpin, KTR Revolex, and Bibby E-flex. Our technical experts provide 24/7 support to minimize downtime. Request a quote or data sheet today to secure your industrial uptime.