US Patent 7527134 Rotational coupling device

A rotational coupling device for use as a clutch and/or brake is provided having a construction enabling improved torque transfer characteristics. The device includes a rotor rotatably coupled to an input shaft and an armature coupled to an output member and configured for selective engagement with the rotor. The rotor includes a hub having a central bore into which the input shaft extends. A support member, such as a spacer or pulley hub is coupled to the rotor hub using an axially projecting lug and notch construction. The structure of the device provides greater clearance for the input shaft and may eliminate the need for keys on the support member.