US Patent 10279864 Bicycle power meter

A chainring structure may include a torque output section comprising a plurality of sprockets having two axially bounding sprockets defining an inner-most and outer-most sprocket and a torque input section configured to attach to a crank assembly. The chainring structure may also include a power meter chamber disposed radially between the torque input section and the torque output section, the power meter chamber including a base surface of a strain measurement section. The power meter may be disposed in the power meter chamber and have at least one strain measurement device attached to the base surface. The torque output section, torque input section, and power meter chamber may be formed as a unitary single piece and configured to dispose the base surface axially between the axially bounding sprockets of the plurality of sprockets.