Predestined for start-stop applications

Predestined for start-stop applications

Predestined for start-stop applications

Backlash-free elastomer or claw couplings are three-part couplings that are designed for highly dynamic acceleration and braking curves and the associated peak torques. Elastomeric couplings are ideal for systems and applications with abrupt start and stop processes or reversal functions, for example in medical technology and the semiconductor industry, in testing and measurement technology or in robotics.

Ruland elastomer couplings are structurally balanced and consist of two hubs and a star-shaped elastic connecting element. The coupling hubs are manufactured with a proprietary rounded claw profile, which ensures a perfect fit of the elastomer star and ensures play-free operation of the coupling. During starting and stopping processes in servo motor drive systems, load torque peaks often occur, which are caused by inertia, friction and high acceleration and deceleration rates during starting and braking.

The elastomer star absorbs these load peaks to minimize shock loads on the engine and other sensitive system components. The elastomer star is available in three different degrees of hardness: 85 Shore A for maximum damping, 92 Shore A for a balanced ratio of damping, torque transmission and torsional stiffness and 98 Shore A for lower damping with the highest transferable torque and torsional stiffness.

The elastomeric couplings can be configured in a variety of ways, as hubs can be assembled in a clamping or adjusting screw design with metric or imperial bore sizes from 3 mm to 32 mm (1/8 to 1-1/4 inch), with or without a keyway. The couplings are considered fail-safe because the interlocking hub claws ensure direct power transmission and the system can be brought to a controlled standstill if the elastomer star breaks. After replacing the elastomer star, full performance of the coupling is restored, significantly reducing maintenance costs compared to couplings that require complete replacement.

All Ruland elastomeric couplings are RoHS3 and REACH compliant. For applications that require special materials, bore sizes or specifications, Ruland creates customized coupling designs. Elastomeric couplings are part of Ruland's comprehensive portfolio of backlash-free couplings, which includes rigid couplings, bellows couplings, multi-plate couplings, beam couplings, Oldham couplings, Controlflex and slot couplings. Complete product information, 3D CAD files and additional technical specifications are available at


  • The elastomer star dampens load peaks
  • The fail-safe coupling ensures continued torque transmission in the event of a break in the elastomeric star
  • Can be configured in a variety of ways to meet customer-specific system requirements
  • Manufactured in Ruland's own factory near Boston, USA
  • Large stock, available for immediate delivery
  • RoHS3 and REACH compliant and in line with the Conflict Minerals Rule
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