Automatic self-guiding lawn mower and mowing method

摘要

An automatic self-guiding lawn mower includes a carriage having first and second sets of electric motors mounted thereon. A blade is operatively connected to and driven by each one of the first set of electric motors for cutting grass, and a wheel is operatively connected to and driven by each one of the second set of motors for moving the carriage. A relay device having at least one trip point is electrically connected to each of the first motors and to the second set of motors. The method of mowing a lawn with the improved lawn mower includes the steps of actuating the first set of motors and attached blades and manually cutting a border around the lawn with the mower. The mower then is positioned adjacent to a peripheral edge of an uncut area of the lawn. The relay devices detect a predetermined change in the power consumption of their respective first motors corresponding to the trip point when the attached blades move between cut and uncut grass, and actuate certain ones of the second motors and attached wheels in response thereto for guiding the mower carriage along the peripheral edge of the uncut area of the lawn. The relay devices reverse the polarity of the second motors and the direction of the mower when the blades encounter cut grass for a first predetermined amount of time, and automatically shut off the first and second motors when the blades encounter cut grass for a second predetermined amount of time.