US Patent 6846127 Gryoscope controlled walk behind trowel

A control module for a walk behind trowel configured to detect and to prevent an uncontrolled or undesirable motion of the trowel. The trowel includes an engine configured to drive rotation of a rotor. The control module includes a gyroscope and a controller. The gyroscope is configured to provide an electrical signal representative of an angular rate of motion of a reference structure on the walk behind trowel. The controller is configured to receive the electrical signal from the gyroscope and to determine when a change in the angular rate of motion of the trowel exceeds a threshold value, and in response, to prevent the engine from driving the rotor to rotate.