You are probably familiar with this situation…

In high volume production environments running multiple shifts, machine downtime can lead to extremely high costs in production losses, which inevitably find their way into unit costs. There are many different causes of torque overload in production equipment, but in each case the use of mechanical torque overload safety devices can be decisive in avoiding damage to machine drive components, and therefore drastically reducing the downtime resulting from malfunction. Safety couplings rapidly disconnect driving and driven shafts at a preset overload torque in a matter of milliseconds, and re-engage easily, meaning that machines can return to operation after a very short time. Of course, in machine design and plant engineering, installation space is usually tight, making it tempting to forego this essential technology.

R+W has recently developed a new option: A backlash-free R+W precision safety coupling with fully split clamping hubs, or SKH for short.

The advantages speak for themselves:

  • precision torque overload protection
  • simple lateral installation between shafts
  • particularly cost-efficient due to reduced assembly time and downtime


Precision mechanical safety couplings from R+W operate according to the spring-loaded ball detent principle and serve as a failsafe element in emergency stop situations.  Key characteristics during normal operation include backlash free and torsionally stiff transmission, for high performance motion control.

The spring-loaded ball detent principle employed here includes Belleville springs specially developed for the purpose of rapid actuation at overload.  Thus, in the event of a machine crash, the new safety coupling with fully split clamping hubs – SKH – separates its input and output shafts within milliseconds, while providing new possibilities for mechanical fits within confined spaces. 
Torque transmission in standard sizes ranges from 0.1 to 2,800 Nm, with higher torques on request.
Technical data of the coupling here.