Patent ID: 8235130
Filing Date: 2012-08-07
Classification: A01B

Abstract:
1. An agricultural machine, comprising: a central frame configured to carry a plurality of farming related work units; left and right wheel sets pivotally mounted to the central frame; a left wheel actuator interconnecting the left wheel set and the central frame and being configured to raise and lower the frame to adjust a depth of the work units, the left wheel actuator including a hydraulic cylinder and a piston extendable and retractable from the hydraulic cylinder; a right wheel actuator interconnecting the right wheel set and the central frame and being configured to raise and lower the frame to adjust a depth of the work units, the right wheel actuator including a hydraulic cylinder and a piston extendable and retractable from the hydraulic cylinder of the right wheel actuator; a depth control system controlling the flow of hydraulic fluid to and from the hydraulic cylinders of the left and right wheel actuators; a left position sensor integrally formed with the hydraulic cylinder and the piston of the left wheel actuator, the left position sensor configured to measure a linear displacement of the piston of the left wheel actuator and provide a signal to the depth control system indicative of a depth of a first portion of the frame; a right position sensor integrally formed with the hydraulic cylinder and the piston of the right wheel actuator, the right position sensor configured to measure a linear displacement of the piston of the right wheel actuator and provide a signal to the depth control system indicative of a depth of a second portion of the frame; wherein: at least one of the left and right position sensors is a linear potentiometer instrument that is configured to output a signal having a voltage that changes with linear displacement of the piston of the corresponding hydraulic cylinder; the depth control system including a controller that receives the signal from the linear potentiometer and can store the voltage of the signal to define a baseline voltage upon selection of a depth of the plurality of farming related work units by an operator, the controller controlling flow of hydraulic fluid to the hydraulic cylinders so as to automatically control pressures in the hydraulic cylinders of the left and right wheel actuators in response to the signals received from the left and right position sensors relative to the baseline voltage to raise and lower the frame such that the depth of the plurality of farming related work units is maintained at the depth of the plurality of farming related work units that was selected by the operator.