Abstract: An aerator with active turf calibration of a ground sensor that provides signals to a controller relating to changes in slope of a ground surface. The controller adjusts the position of a coring head based on signals from the ground sensor. The controller determines an offset from a neutral position of the ground sensor based on signals from the ground sensor on a flat surface during aeration compared to the neutral position of the ground sensor on a flat surface from static calibration.

Abstract: An aerator with active turf calibration of a ground sensor that provides signals to a controller relating to changes in slope of a ground surface. The controller adjusts the position of a coring head based on signals from the ground sensor. The controller determines an offset from a neutral position of the ground sensor based on signals from the ground sensor on a flat surface during aeration compared to the neutral position of the ground sensor on a flat surface from static calibration.

Abstract: A walk behind aerator hydrostatic traction drive system includes left and right rear wheel hydrostatic motors driving left and right rear wheels positioned forwardly of a coring head, and a front wheel hydrostatic motor driving a single steerable front wheel carried in a pivotal yoke. The pivotal yoke is coupled to a handle assembly attached to a neck extending upwardly and forwardly for pivoting the single steerable front wheel about a vertical pivot axis. A check valve is connected in parallel to the front wheel hydrostatic motor. The check valve opens if the walk behind aerator moves in a forward direction and the handle assembly is turned to pivot the single steerable front wheel and the front wheel rotates more than each rear wheel, or if the walk behind aerator moves in a reverse direction.