Patent ID: 7886627

Claim:
A coupling device including: first and second rotatable bodies, said first rotatable body including drive formations located thereon; first and second sets of engagement members arranged for rotation with the second rotatable body and for selectively engaging the drive formations thereby coupling the first and second rotatable bodies together to transfer drive between the first and second rotatable bodies; and an electro-magnetic actuator for controlling engagement of the first and second sets of engagement members with the drive formations; wherein the first and second sets of engagement members are moveable into and out of engagement with the drive formations independently of each other, the arrangement being such that when the drive formations are engaged by the first and second sets of engagement members and a braking force is transmitted the first set of engagement members drivingly engages the drive formations, and the second set of engagement members is in an unloaded condition and when a driving force is transmitted the second set of engagement members drivingly engages the drive formations, and the first set of engagement members is then in an unloaded condition.