Abstract: A zero turning radius mower park brake system includes a park brake pawl on a transmission which engages a park brake to a pair of independently driven traction wheels. A park brake link may be pivotably mounted to the park brake pawl and connected to a left steering lever and a right steering lever. The park brake link may pivot while moving the park brake pawl forward to a park brake engaged position if only one of the steering levers is moved outward from a neutral traction drive position.

Abstract: A robotic mower housing includes a one piece molded bottom chassis having an inner wall and an outer wall. A top cover is removably attached to and covers the bottom chassis. An outer seal is provided between the outer wall of the bottom chassis and the top cover, and an inner seal between the inner wall of the bottom chassis and the top cover. The vehicle control unit and other electronic components may be located in the inner cavity inside the inner seal and an outer cavity between the outer seal and the inner seal.

Abstract: A height of cut adjustment assembly for a robotic mower includes a height of cut drum secured to a bottom chassis of the robotic mower and having internal spiral threads, a motor cup supporting a cutting blade motor and having external spiral threads that engage the height of cut drum, and a blade shield fastened to the motor cup. The blade shield and the motor cup may be rotated to change height of cut. The blade shield and motor cup may be rotated one revolution to move the motor cup and blade shield vertically between a minimum and a maximum cutting height. Detents engage the motor cup with the drum at a plurality of different cutting heights.

Abstract: A robotic mower stuck detection system includes a boundary sensor on the robotic mower that can detect when the robotic mower reaches a boundary wire, an accelerometer on the robotic mower that can detect when the robotic mower encounters an obstacle; and a vehicle control unit on the robotic mower having a timer that is reset each time the robotic mower reaches a boundary wire or encounters an obstacle; and executes a stuck vehicle task if the timer exceeds a specified maximum time without being reset.

Abstract: A robotic mower housing includes a one piece molded bottom chassis having an inner wall and an outer wall. A top cover is removably attached to and covers the bottom chassis. An outer seal is provided between the outer wall of the bottom chassis and the top cover, and an inner seal between the inner wall of the bottom chassis and the top cover. The vehicle control unit and other electronic components may be located in the inner cavity inside the inner seal and an outer cavity between the outer seal and the inner seal.

Abstract: A height of cut adjustment assembly for a robotic mower includes a height of cut drum secured to a bottom chassis of the robotic mower and having internal spiral threads, a motor cup supporting a cutting blade motor and having external spiral threads that engage the height of cut drum, and a blade shield fastened to the motor cup. The blade shield and the motor cup may be rotated to change height of cut. The blade shield and motor cup may be rotated one revolution to move the motor cup and blade shield vertically between a minimum and a maximum cutting height. Detents engage the motor cup with the drum at a plurality of different cutting heights.