Work meter for a crank drive

摘要

The work produced by a person on a bicycle could heretofor only be measured in a stationary manner. To do this, a flywheel disc was driven by the cranks via a drive disc in the form of a chain wheel or pulley by means of a chain or belt, the flywheel disc being braked, for example by a friction or eddy-current brake. The rotational speed of the flywheel disc and the braking force effected on this were a measure for the work produced. This type of work measurement does not enable non-stationary determination of the work done of a person, since no energy is converted into forward movement. In the work measurement proposed according to the present invention, the work produced is measured directly on the bottom bracket bearing of the bicycle. The pedal power is converted into an electrical signal by the deformation of a suitable bending element, on which strain gauges are applied, and transmitted to a receiver connected to the bicycle frame by means of inductive transmission. The pedalling speed is determined by measuring pedalling frequency. Both values, pedal power and pedal speed, are processed in a microcomputer on the bicycle, indicated and stored.