Controlling ground clearance in a self-propelled agricultural product applicator

A self-propelled agricultural product applicator, having a ground engaging wheel operatively connected to a frame by a trailing-arm suspension system, with the frame being adapted for supporting at least one product container, the frame defining forward and rear ends of the frame, a longitudinally extending central axis of the frame extending from the rear to the front of the frame in a direction of travel of the applicator, and a vertical axis of the frame, and the suspension system comprises:

• an upper suspension arm, a lower suspension arm, an air strut, and an angular position sensor, operatively interconnected to one another and disposed between the ground engaging wheel and the frame;
• the upper suspension arm defining a frame attachment point thereof, adapted for fixed attachment to the frame;
• the lower suspension arm defining a rolling axis of the ground engaging wheel and adapted for supportive attachment thereto of the ground engaging wheel for rotation of the ground engaging wheel about the rolling axis of the wheel;
• the upper and lower suspension arms also defining respective forward and aft ends thereof, with the forward ends being adapted for operative pivoting connection to one another through an angular rotation about a suspension pivot axis extending generally parallel to the rolling axis of the wheel and disposed forward of the rolling axis of the wheel, and the aft ends of the upper and lower suspension arms being disposed respectively aft of the frame attachment point and rolling axis, and with the aft ends of the upper and lower suspension arms being respectively adapted for operative attachment thereto of the air strut;
• the air strut having an upper end thereof adapted for operative attachment to the aft end of the upper suspension arm, and also having a lower end thereof adapted for operative attachment to the aft end of the lower suspension arm;
• with the air strut being configured for receiving a flow of pressurized air from an air power source, and for extending and retracting in response to the flow of pressurized air, to thereby respectively lower and raise the rolling axis of the wheel with respect to the frame attachment point;
• and
• the angular position sensor being operatively connected between the upper and lower suspension arms for detecting an angular rotation of the upper and lower arms with respect to each other about the suspension pivot axis, the angular rotation detected being indicative of a distance between the rolling axis of the wheel and the frame attachment point, and thereby also indicative of a ride height of the frame above the ground.

A method for controlling the height of a frame of a self-propelled agricultural product applicator above a ground surface by:

• connecting the frame to a ground supporting wheel of the applicator using a trailing link suspension system including an upper suspension arm attached to the frame, a lower suspension arm providing sole support of a ground engaging wheel attached thereto, the upper and lower suspension arms having respective forward ends thereof connected to one another at a suspension pivot axis for pivoting angular rotation relative to one another about the suspension pivot axis, and an extensible air strut operatively interconnected between the upper and lower arms;
• connecting an angular position sensor between the upper and lower suspension arms for detecting an angular rotation of the upper and lower arms with respect to each other about the pivot axis, the angular rotation detected being indicative of a distance between the rolling axis of the wheel and the frame attachment point, and thereby also indicative of a ride height of the frame above the ground;
• and
• controlling a flow of pressurized air to the air strut achieve a desired angular rotation as detected by the angular position sensor of the upper and lower suspension arms about the suspension pivot axis, to thereby control extension of the air strut and height of the applicator frame above the ground surface.