Abstract: A mower obstacle avoidance system includes a pair of sensors mounted on a robotic mower, each sensor emitting ultrasonic signals in a trajectory in front of the robotic mower, and receiving reflected signals from the other sensor. A controller commands a traction drive system to stop and turn the mower if either of the pair of sensors receives a reflected ultrasonic signal from an object at a stop distance in front of the robotic mower, if the object also is within a window of passage based on a height of cut, a width and a height of the robotic mower.

Abstract: A quick attach rotary mower blade system includes a spindle having a first pair of fan-shaped projections, and a spring-loaded collar having a bore through which the lower end of the spindle extends and a second pair of fan-shaped projections. A mower blade mounting hole includes a circular center opening and a pair of fan-shaped openings. The mower blade may be installed on the spindle by aligning the pair of fan-shaped openings with the first and second pairs of fan-shaped projections, moving the mower blade and spring-loaded collar upwardly, and rotating the mower blade and spring-loaded collar 90 degrees to interlock the second pair of fan-shaped projections between the first pair of fan-shaped projections.

Abstract: A quick attach rotary mower blade system includes a spindle having a first pair of fan-shaped projections, and a spring-loaded collar having a bore through which the lower end of the spindle extends and a second pair of fan-shaped projections. A mower blade mounting hole includes a circular center opening and a pair of fan-shaped openings. The mower blade may be installed on the spindle by aligning the pair of fan-shaped openings with the first and second pairs of fan-shaped projections, moving the mower blade and spring-loaded collar upwardly, and rotating the mower blade and spring-loaded collar 90 degrees to interlock the second pair of fan-shaped projections between the first pair of fan-shaped projections.

Abstract: A quick attach rotary mower blade system includes a blade holder secured to a mower spindle with a shoulder bolt, a pair of upwardly extending protrusions on the blade holder, and a spring biased plunger extending downwardly from the blade holder. A rotary mower blade has a center hole that slides over the shoulder bolt, compresses the spring biased plunger, and rotates over the protrusions to an engaged position.

Abstract: A quick attach rotary mower blade system includes a blade holder secured to a mower spindle with a shoulder bolt, a pair of upwardly extending protrusions on the blade holder, and a spring biased plunger extending downwardly from the blade holder. A rotary mower blade has a center hole that slides over the shoulder bolt, compresses the spring biased plunger, and rotates over the protrusions to an engaged position.

Abstract: A zero turn mower steering system including left and right motion control levers independently pivotable between forward, neutral and reverse positions to rotate left and right rear drive wheels respectively at forward, neutral and reverse speeds. Left and right position sensors on the left and right motion control levers provide electronic signals to an electronic controller that provides a left front wheel steering angle signal and a right front wheel steering angle signal. Each steering angle signal is based on a distance the electronic controller calculates from each of the left and right rear drive wheels to an instantaneous center point of a turn.

Abstract: A zero turn mower steering system including left and right motion control levers independently pivotable between forward, neutral and reverse positions to rotate left and right rear drive wheels respectively at forward, neutral and reverse speeds. Left and right position sensors on the left and right motion control levers provide electronic signals to an electronic controller that provides a left front wheel steering angle signal and a right front wheel steering angle signal. Each steering angle signal is based on a distance the electronic controller calculates from each of the left and right rear drive wheels to an instantaneous center point of a turn.

Abstract: A mower deck leveling system includes first and second electric actuators that change the spacing between a first side of the mower deck and a lawn and garden tractor frame, and the spacing between a front of the mower deck and the lawn and garden tractor frame. First and second sight levels on the mower deck indicate if the first side of the mower deck is level with a second side of the mower deck, and if the front of the mower deck is level with the back of the mower deck. At least one electric switch in the operator station is connected to the electric actuators.

Abstract: A method for controlling the population inversion in a solid state laser material by optically pumping the material with a laser beam having a wavelength corresponding to the absorption band of the laser material and the output of which is spatially and temporally modulated. Spatial and temporal modulations of the population inversion in the pumped material are achieved by means of a two-dimensional spatial modulator positioned between the pump laser beam and the pumped laser material, the modulation being thermo-optically controlled by a scanning electron or laser beam or electro-optically controlled by a scanning electron beam or acousto-optically controlled by a two-dimensional acousto-optical modulator. Utilization of a lens between the spatial modulator and the optical cavity of the laser material permits electronic deflection of the output from said laser material by focusing the beam transmitted through said spatial modulator.