Everything you need to know about safety couplings

With the plethora of safety options being offered in the field of electronics and control technology it is easy to forget the many advantages of the humble mechanical safety coupling. However, electronic safety components have three significant disadvantages and the first is reaction time. If an overload occurs in a machine, a signal from the monitoring circuit does not reach the motor controller until several milliseconds later following a sharp increase in torque. In that time the controller attempts to increase torque further in order to reach the set-point value. A mechanical safety coupling on the other hand will disconnect the drive from the load in a third of the time. Secondly, electronic machine monitoring is not suitable for high speeds due to the large centrifugal mass of rotating parts. And finally equipment fitted with electronic monitoring systems generally needs multiple sensors to ensure optimal protection. This relatively complicated arrangement multiplies the points of failure. Conversely only a single mechanical coupling is required per axis and it is also simple to install and adjust. This overview of the benefits of mechanical safety and overload couplings introduces an extremely valuable book dedicated to these important drive components. It is written by R+W, a European leader in the design and manufacture of couplings. The publication then provides a guide to the functional principles of the different types, their fields of application and selection criteria. This hard-backed book is entitled Safety and Overload Couplings ñ backlash-free torque limitation for automation technology. It is available in from R+Wís sole UK distributor, Tandler Precision Limited on 01604 588056 or via sales@tandler.co.uk