Over time, agricultural machines, including sprayers and other applicators, have gotten larger to increase machine efficiency. These larger machines are also heavier, which require larger steering forces that can put substantial stresses on steering components and the joints that connect steering components to each other. Examples include connections at the ends of hydraulic steering cylinders to mounting tabs of various components. One end of each steering cylinder is connected to a mounting tab or lug of a steering arm that turns a respective wheel to steer, and a second end of each steering cylinder is connected to a mounting lug on the frame or axle, such as an axle-width adjusting slide bar or other component for adjustable-width machines. Pushing and pulling the steering arms with the substantial steering forces in these large agricultural machines make the connections between the ends of the steering cylinders and the mounting lugs susceptible to loosening and wear, which can lead to sloppy steering feel and component failure. Attempts have been made to improve maintaining tightness at the joints between the steering cylinders and mounting lugs. These attempts include mounting a spherical bearing in each mounting lug and bolting the cylinder end yokes to the mounting lug, through the inner race of the spherical bearing. However, the bolts used in this way as the spherical bearing shafts are typically standard bolts, which often provide a loose fit between the bolts and the inner races. Efforts to ensure that a spherical bearing's inner race rotates with respect to its outer race instead of with respect to the loose-fitting bolt include mounting split spring bushings in each yoke lobe of the cylinders' end yokes. Tightening the bolt clamps the engaging end/edge surfaces of the split spring bushings and the end/edge surface of the spherical bearing's inner race, which helps hold the spherical bearing inner race fixed with respect to the cylinder yoke and therefore rotate with respect to its outer race. However, when the system is subjected to the large steering forces, the bolt can loosen over time. This unloads the longitudinal clamping force between the end/edge surfaces of the split spring bushings and the spherical bearing's inner race, which makes the spherical bearing's inner race susceptible to rotating in unison with its outer race and instead tends to rotate with respect to the bolt. If the bolt is not retightened to reapply the longitudinal clamping force between the end/edge surfaces of the split spring bushings and the spherical bearing's inner race, then the continued rotation of the inner race with respect to the bolt causes wear in the bolt, which further loosens the joint. Attempts have been made to maintain tightness of the bolt by using a slotted nut and split pin or cotter pin to prevent rotation of the slotted nut. However, slotted nuts can occasionally rotate slightly before the cotter pin sufficiently jams and prevents their further rotation. This can provide enough looseness to unload the longitudinal clamping force between the end/edge surfaces of the split spring bushings and the spherical bearing's inner race and allow rotation of the inner race on the bolt and correspondingly accelerate wear.
USPTO Backgrounds
USPTO Backgrounds