The recently introduced ROBA– contitorque , developed by Mayr Antriebstechnik and now available from Mayr Transmissions, offers the machinery manufacturer a clutch or brake unit for constant slip applications. Overload clutches are usually based on friction or positive locking which can protect machine components against damage due to overload however they may not be suitable for continuous slip operation .
The disadvantage of friction type torque limiters is that the torque can vary as a result of changes in friction value due to ambient conditions , run-in or wear , slip–stick effect due to a change from static to sliding friction. As the friction linings wear the torque transmission can reduce and any resultant dust contaminating the machinery. Consequently torque repetition can be an inaccurate process .
With the ROBA – contitorque , Mayr has overcome this problem combining wear free torque transmission with precise torque limitation , free of any slip – stick effects.
Based on the magnetic hysteresis principle , during normal operation the torque is transmitted synchronously and backlash free between the driving input hub and driven output flange . In the event of an overload the clutch slips, with the input and output components rotating relative to each other , the so called slip speed . The hysteresis effect ensuring constant torque between the driver and driven components.
The ROBA – contitorque can be applied wherever a combination of precise torque limitation together with wear and maintenance free operation is required as on screw capping machines , constant tension foil winding and slitting machines , railway points actuating systems .
The standard range of four sizes currently available covers the torque range 0.1 – 6 Nm ,with a stainless steel sealed version for applications requiring this option.