Jaw Coupling replacement coupling to replace Lovejoy, Boston Gear, SKF Jaw couplings - L type, S type, AL type, SS type and CJ type.

Jaw coupling compared to a Twin Spring Coupling.

  • Speeds: Up to 7000 rpm
  • Peak Torque Largest Size ft lbs 150ft lbs (203Nm) to 500ft lbs (678 Nm)
  • Standard Coupling sizes 1/4″-1-3/4” (8-45mm)
  • Temperature: -20° to +290°F , (-4° to +140°C)
  • Connection: Spline (Square, Hex, Keyway, No Keyway
  • Torsionally rigid design at angles less than 10°
  • Minimal backlash
  • No moving parts
  • One piece design 

The Jaw coupling has been an industry standard for a number of years, for engineers looking for a flexible coupling solution for high speed minimal misalignment applications. Companies like Lovejoy, TB Woods, Tsubaki and Ruland all have Jaw Couplings but the design is all the same so they all fail the same way.

The traditional couplings like universal joints are all a 3 piece design, which means 3 things can go wrong – Worn Spider insert, cracked hubs are just two of the things that can go wrong.

The other downside is it wasn’t able to handle angles larger than 3° before they start to wear out. The Spider insert starts to wear and will disintegrate, while the coupling won’t fail it will be reduced to metal on metal increasing vibration and leading to potential equipment damage.

Add to that, the fact it cannot handle large torque loads makes them limited in their use and mechanical engineers have to design their equipment around these limitations.

1° of jaw misalignment means exponential insert wear

Such a low angle of usage means they will need constant maintenance as working at 1° will mean it will be constantly be wearing the spider as any weight or variation in load will mean it will not be at its optimal angle of usage. The insert mainly

One product replaces many – Jaw Couplings come in L Jaw and CJ Jaw configurations – All low torque as any angle of use over the 1° the spider insert will wear quickly.

Not only does Twin Spring Coupling offer the dampening effect of the spider by means of its twin spring design it also can be used at higher angles of use and at high speed, so offering the advantages of the Jaw coupling but without the downside.

The Twin Spring coupling dual spring design allows for comparable windup, non-balanced maintenance free coupling solution with the positives of high torque capacity and increased flexibility even at speed.

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

Twin Spring Coupling has no insert to wear and replace

The Twin Spring coupling contains no internal components that require maintenance so we offer the positives of high 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.

This also allows the Twin Spring coupling to run at the same high RPMs that both the L jaw and S Jaw couplings do.

The win win here for Twin Spring coupling over Jaw couplings are.

Higher angle of misalignment, without wear.

Twin Spring design dampens vibration like the spider in the middle of the jaw coupling.

Same high RPM usage as the L Jaw and S Jaw couplings.

Twin Spring Couplings advantages over a jaw coupling

One piece design means no disassembly to replace spider insert, a straight swap out when the Twin Spring coupling has reached the end of its useful life.

High speed.

Highly flexible to 45 degrees.

High Torque Up to 6000 In lbs.


RulandJC series, JS series, 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.

Lovejoy – L090, L100, AL100, SS100, L110, AL110, SS110, L150, AL150, SS150, L190, L225, L276, C276 (SOX) CJ 48/60 42/55, CJ38/45, CJ28/38 series.

R+W America – EK series.

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

Boston Gear – FC25-FC45 FC30, FC38, FC45 series (XFCBB, XFCR, XFCA inserts).

Ringfeder – GWE Z5106.1, GWE Z5104.1, GWE 5104.

GAM – EKZ series, KM series, KP series, KG series.

SIT – Trasco ES series.

KTR – Rotex series.

SKF FRC90, FRC110, L100, L110, L150, L190, L225.

Which jaw coupling do you need to replace