US Patent 7634949 Transmission chain monitoring system

A transmission chain comprises has a data collection device mounted on at least one of the links. A strain gauge sensor is mounted on the inwardly facing surface of an outer link plate symmetrically about a centre link thereof and measures the strain on the link plate. The measurements are compared to a threshold and a visual indicator mounted on the chain is activated if the threshold is exceeded. The data collection device can be controlled by a first controller device that simply switches it between a quiescent state to an overload detecting state or a second controller type can be used for data-logging and analysis.