Patent ID: 8141438

Claim:
A power sensing assembly for an apparatus powered by a user applied force to a pedal assembly that drives a hub through a flexible drive member, comprising: a cassette adapted to be removably secured to the hub and configured to be drivingly interconnected with the pedal assembly through the flexible drive member, wherein the cassette includes a body having external teeth configured for engagement with the flexible drive member, wherein the cassette body defines an internal cavity, and wherein the cassette further includes a removable mounting arrangement configured for removably securing the cassette to the hub; and a torque transfer arrangement interconnected with the cassette body and extending across the internal cavity defined by the cassette body, wherein the torque transfer arrangement transfers torque from the external teeth of the cassette body to the hub, and wherein the torque transfer arrangement includes one or more torque sensing elements, wherein the torque sensing elements measure the torque transferred from the cassette body to the hub and thereby the torque experienced by the hub in response to the application of power by a user to the pedal assembly.