Coupling technology to replace Servo couplings.

Servo Coupling verses Twin Spring Coupling
Twin Spring Coupling features

  • Speeds: Up to 7000 rpm
  • Nominal Torque  150 ft lbs – 500ft lbs (203 – 678Nm)
  • Standard Coupling sizes 1/2″ to 1 3/4” (12.7-46mm)
  • Temperature: -20° to +290°F , (-4° to +140°C)
  • Connection: Spline, Keyway, Square/Hex
  • Torsionally rigid design at angles less than 10°
  • Minimal backlash
  • No moving parts

The servo coupling has been an industry standard for a number of years for motion control, for engineers looking for a flexible coupling solution for high speed minimal misalignment applications.

The downside is it wasn’t able to handle angles much larger than 2° and the ability to handle torque is minimal. The Twin Spring coupling dual spring design allows for minimal windup, non-balanced maintenance free coupling solution with the positives of increased torque capacity and increased flexibility even at speed which ideal for motion control for servo motors. ​

This means where applications that need increased torque and misalignment while still working at high speed can now be achieved without resorting to a jaw or elastomeric coupling (which still cannot work at increased angle misalignment.

The Twin Spring coupling contains no internal components that require maintenance so we offer the positives of increased torque and misalignment in one coupling without the worry of maintenance. ​

At low angle misalignment, Twin Spring coupling maintains its torsional rigidity and continues to do so as misalignment continues to increase due to the pivoting central ball bearing which allows torque to transfer through the coupling.

Lets break down each coupling type

Beam Couplings

Whether single or multi beam , are very high speed but very low torque capable coupling, with the ability to flex to only 5 degrees makes them very limited in what they can be used for.

Their torsional stiffness (the coupling is a piece of metal with cuts made to allow it to flex) is quite high but this stiffness comes at the price of no flexibility, any machine wear because of changes of weight or angle of use means they wear quickly

Bellows Couplings

Like the Beam coupling, the Bellows coupling is almost identical in features and weaknesses. The Bellows can run at high speed but can only flex to 6 degrees, again making it another coupling that will wear quickly is any change to the angle of misalignment occurs, either intentional or not.
The same torsional stiffness as the Beam, the Bellows is a high speed coupling but with its low torque output and small size makes its use limited.

Jaw Coupling – Both L type and Curved Jaw

Jaw or L jaw or S Jaw couplings are different to beam couplings or bellows coupling as they are made up of 3 pieces, 2 hubs “jaws” and a polyurethane “hub” in the center. While the Jaw coupling can also run at high speeds it can can only work at 2 degrees misalignment before the center hub starts to wear. The Jaw coupling can only handle small amounts of torque as well.
The L jaw coupling is what’s called a safety coupling, which means if the center hub fails the jaws clamp together and it can continue to function but without the hub to reduce vibration it will start to damage machinery components unless replaced.

There are another few Servo based coupling like the Oldham, Disc coupling and double loop but their design characteristics are the same as the couplings above, high speed but minimal flexibility and minimal torque.


Helical – W, DS, MCA,MC7, A and H series

Ruland – JC jaw , MJC jaw series

Guardian Coupling – 28/38, 38/45, 42/55, 48/60 series

TB Woods – L090, L100, AL100, SS100, L110, AL110, SS110, L150, AL150, SS150, L190, L225, L276 series, Sureflex WE,2,3,4,5,10,20,30,40

Lovejoy – C276 (SOX) CJ 48/60 42/55, CJ38/45, CJ28/38 series, Timken

R+W America – EK series

Tsubaki – L099, L100, L110, L150, L190, L225, L110A series

Boston Gear – FC25, FC30, FC38, FC45 series

KTR – Rotex AL-H 28,38,42,45,48 GJL 38, 42,48,55, 65 series

Altra Motion Control

Rexnord – Omega Orange 10,15, 20, 30, 40, Omega HDY 5, 10,15, 20, 30, Falk Wrapflex 10R, 20R, 30R.

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