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The Kop-Flex® KD® coupling product line was designed for pump, screw and reciprocating compressor applications.  These high-value disc couplings are manufactured to finishes typically found on higher-cost offerings, providing simplified maintenance and best in class performance. The superior KS coupling product line is balanced to tighter tolerances for higher operating speeds and meets API 671 specifications


For over 30 years our High-Performance products have been the standard for reliability and performance. Our KD® and KS product lines use similar disc pack geometry and benefit from our experience in gas turbine and centrifugal compressor applications.


Kop-Flex® also offers resilient coupling designs which can be torsionally soft to isolate damaging vibratory torques or provide damping to minimize severe oscillations due to peak torques. The Max-C® replaceable rubber elements are available in various durometers in order to  tune  drivetrains away from damaging resonant frequencies.





The KD® product line provides great value. The feature-packed KD20, KD21, and KD23 all come standard with the following:



  • Fully Machined Construction
  • Scalloped Disc Profile
  • Stainless Steel Unitized Disc Pack
  • As Machined AGMA Class 9 Balance
  • Forged Steel Components



  • Improves dynamic balance compared to cast components
  • Optimize stress distribution and reduces reaction loads
  • Higher strength and facilitates replacement of the flex element
  • Allows for higher operating speeds, Class 10 optional 
  • Allows for smaller, lower weight couplings




These factors combine to provide “best in class” torque capacity by size, allowing for the most power-dense coupling selection to be made.



Torsionally Tuned Spacer 

By machining a forging instead of using off the shelf cast components. The stiffness of the spacer can be adjusted to torsionally tune the coupling.


Shrink Disc Mounting

By incorporating a shrink disc mounted on the hub body the coupling can be installed or removed without heating the hubs.


Keyless Tapered Bushing

By using a tapered bushing, interference fit hubs can easily be removed through the use of hydraulic fittings and equipment.


The KD2® and KD20 are user-friendly spacer couplings designed to meet API 610 / ISO 13709.   The medium-duty KD2® and the heavy-duty KD20 are for applications requiring moderate shaft separations.  Installation and maintenance are simplified by the use of only three main parts: two hubs and a factory assembled center section.


  • Drop-out spacer style
  • Fully machined steel construction
  • AGMA Class 9 Balance standard
  • AGMA Class 10 or 11 Balance optional
  • Many sizes available to fit your application
  • Standard shaft separations for industrial applications
  • Many typical center section lengths stocked
  • For higher speed applications consider a KS coupling




The KD21 is an economical spacer coupling designed for pump applications. The unitized disc packs and close tolerance bolts provide good dynamic balance.  The minimal number of components creates an economical disc coupling solution.


  • Economical spacer style
  • Fully machined steel construction
  • AGMA Class 9 Balance standard
  • AGMA Class 10 Balance optional
  • Many sizes available to fit your application
  • Standard shaft separations for industrial applications
  • Many typical spacer lengths stocked
  • For higher speed, applications consider a KS coupling




The KD23 is a flywheel style coupling, designed for use on reciprocating equipment. The machined plate adapter is designed to connect to standard SAE flywheels.


  • Flywheel style
  • Fully machined steel construction
  • AGMA Class 9 Balance standard
  • Torque ratings optimized for compression industry
  • Many sizes available to fit your application







The Max-C® CB is a resilient coupling used on reciprocating equipment to isolate damaging vibratory torques from connected equipment.  Contact Kop-Flex® Engineering with specific application information so a custom-engineered and torsionally tuned Max-C® can be designed to your requirements.  


  • Torsionally soft
  • Rubber block in cylindrical shape
  • Various durometers available
  • Custom engineered for applications
  • Maintenance free operation
  • Hybrid designs are available with disc, gear or diaphragm flex elements
  • For applications requiring a higher degree of torsional stiffness, consider a Max-C® WB. Contact Kop-Flex® Engineering for details




A proven and unique concept for a non-lubricated “maintenance free” flexible coupling. The Elastomeric® provides long service life for the coupling, and equipment bearings and seals.  The design concept provides low-cost power transmission with the added benefits of absorbing shock loads and damping damaging vibrations.


  • Cushions the shock of impact loading
  • Dampens torsional vibrations
  • Rubber in compression increases torque capacity over shear
  • Torsionally soft
  • Dynamically stable
  • Split insert facilitates installation





KS disc couplings are designed to meet API 671 specification requirements and provide a less expensive alternative when application speeds are in the intermediate range. They are typically used for turbine and motor drive applications, where the additional features of the High Performance product line are not required.


  • Economical API 671 solution
  • Drop out anti-flail center section
  • Dynamically balanced for higher speed applications
  • Rigid hubs allow for large bore capacity
  • Includes shims to facilitate axial alignment





Kop-Flex® High Performance couplings satisfy the requirements for high speed applications. The marine style, MP High Performance Disc coupling is typically used on steam turbines, generators and compressors and meets API 671 specification requirements.


  • Higher torque capacity than KS product line
  • Full alloy steel construction
  • Removable center section
  • Improved anti-flail design
  • Rigid hubs allow for large bore capacity
  • Reduced windage disc pack cover





Building on our foundation of reliability, safety and exceptional performance, the Kop-Flex® High Performance Disc Coupling 2.0 was created for your highly engineered equipment.  To achieve the best weight and power density possible, the coupling diameter was reduced while the torque capacity was aligned with the application.  The HPD2.0 design is the lightest coupling available on the market, improving equipment performance in the most critical applications. 


  • Optimized disc geometry improves stress distribution
  • 20-30% weight reduction over previous generation
  • Lowest overhung moment available
  • Reduced OD improves balance and reduces windage
  • 22 sizes driven by common customer shafts
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