Permanent magnetic clutch for medical devices

SG Transmission has designed and manufactured a permanent magnetic clutch for a medical device manufacturer, replacing the need for a brake and clutch saving money and weight.

The fail-safe clutch utilises rare earth permanent magnets to generate the magnetic field keeping the clutch engaged, should the power fail.

The innovative clutch was designed for a blue-chip manufacturer to replace the existing clutch in a drive mechanism, which needed power to engage the clutch.

The existing configuration could, in the event of power failure, allow the mechanism to potentially become free moving in an uncontrolled manner. Standard practice would be to use a fail-safe brake in this arrangement to control the free movement, which would create an additional cost.

The innovative permanent magnetic clutch has the potential to replace both components and not only save space, weight and part count, but there is also a cost saving.

Paul Short, technical manager, said: “If the drive system uses a gearbox where the output shaft cannot be ‘back driven’ then, in some applications, by employing a permanent magnet clutch this mechanical advantage can be used to provide a positive stop/hold action in the event of a power failure. Therefore, the permanent magnetic clutch is suitable for many sectors, including medical and military, where a permanently engaged clutch would be advantageous.”