Oldham/Universal Couplings


  • Protects driven component by serving as a mechanical “fuse” – an inexpensive replaceable plastic midsection shears under excess load
  • Protects support bearings by exerting consistently low reactive forces, even under large misalignments
  • Zero backlash and moderate torsional stiffness
  • Electrical insulation
  • Accommodates large radial misalignment in a short length
  • Accommodates much larger angular misalignment then standard Oldham coupling
  • Easy installation in blind or difficult installations when through-bores are used
  • Economically priced compared to other couplings with similar performance characteristics
  • Inexpensive replaceable wear element
  • Low moment of inertia


  • Lower peak torque and torsional stiffness than standard Oldham coupling
  • Slightly non-homokinetic transmission (that is, the driven and driving shafts don’t move at exactly the same speed throughout one rotation) when angular misalignment is significant
  • Axial reactive loads exerted on support bearings when torque approaches maximum
  • Accommodates only a small axial misalignment

Typical Applications:

Types UC and UI are used in light-duty applcations with large angular misalignment, including instrumentation and positioning systems; UA is used in heavy-duty mission-critical high-torque applications requiring a fail-safe coupling, including servo-controlled valves, mining, and crushing equipment.

Variations offered by OEP Couplings:

UC Configuration

Similar to the classic Oldham coupling, but with a torque-transmitting element that’s round in cross-section, rather than rectangular, allowing pivoting similar to a universal joint.

UI Configuration

A higher torque, higher stiffness variation without the mechanical fuse protective function. Cylindrical fins overlap, with the axes of the two cylinders intersecting, allowing for pure universal action and smooth angular flexion, while still accommodating a large radial misalignment.

UA Configuration

An ultra-high-torque variation of the UI, with a metal midsection and Delrin (or high-temp plastic) wear bushings.  The strongest low-reactive-force flexible shaft coupling available, easily scaleable up to 4 inch outer diameter.


  • Materials for midsection:  Delrin – for general use; low friction, long wear.  High-temperature high-performance thermoplastic; for high-temperature or for more demanding applications.
  • Materials for hub:  Aluminum (alloy 2011 for UI and UC; alloy 7075 for UA); 303 stainless steel; brass (UI and UC); and electroless-nickel-plated steel (UA).
  • Shaft attachment options: Set screw with or without keyway, clamping with or without keyway

Why OEP?

Advantages of OEP’s Oldham/Universal over other manufacturers’ couplings with similar designs:

  • Higher torsional stiffness, longer service life, and more consistent performance from one coupling to another due to much tighter machining tolerances, better surface finishes, and one-piece hubs machined from bar
  • Higher static break torque and higher peak torque due to small but critical geometrical features, details of fabrication techniques, and the use of advanced materials and processes
  • Higher RPM rating because of dynamic balance inherent in every coupling

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