1. Field of the Invention
The present invention relates generally to soil openers that use a disc assembly to open the soil prior to injection of a fertilizer or seed into the ground. More specifically, the present invention concerns a sectored disc assembly for use in such a soil opener, a removable disc sector of a sectored disc assembly, as well as a method of replacing a disc sector of a sectored disc assembly.
2. Discussion of the Prior Art
Those of ordinary skill in the art will appreciate that farmers often use no-till planting techniques to produce all types of agricultural crops. Such no-till techniques minimize the disturbance to the soil and leaves the stubble, or organic matter from the previous crop, standing in the field. This, in turn, reduces water runoff in the field, thereby greatly reducing erosion of the top soil.
Typically, no-till planting involves using a rotatable disc soil opener to cut a furrow in the soil as it is pulled across a field, creating a small disturbed soil zone. Fertilizer, seeds, or both, are then injected into this disturbed soil zone, after which the furrow is closed. The closing of the furrow can be accomplished by naturally allowing the disturbed soil to flow back into the furrow, or by following the rotatable disc soil opener with a closing wheel designed to push soil into the disturbed soil zone and close the furrow. Often, the opening of the furrow, formation of the seed bed, injection of fertilizer, seed, or both, and closing of the furrow are accomplished in a single pass with a soil opener that includes a rotatable disc, an injector foot, and a closing wheel.
Conventional rotatable discs used in soil openers have been formed, most typically out of carbon steel, as single, annular bodies for rotation about a spindle on the soil opener. While this unitary construction has been satisfactory in some respects, such solid discs are very heavy components that can be difficult to handle and are often expensive to produce. As the rotatable disc component of a soil opener directly contacts the soil as the implement moves through a field, the disc is subject to considerable stress and is exposed to damage. Damage to a rotatable disc, often the result of transport, inexperienced or poor operators, or hitting a railroad track or rocks in the soil, requires replacement of the entire disc. Such disc replacement is expensive and time consuming, as the entire heavy disc must be removed from the soil opener, typically involving tedious disassembly of the entire supporting frame, and only then can an entire new disc be installed.
The cost associated with whole disc replacement can be disproportional to the amount of damage to the disc, such as when a single portion of the edge of the disc is damaged from hitting a rock. Additionally, the replacement of the whole disc results in considerable down time of the implement, as heavy components must be elevated out of the soil to facilitate removal of the disc to be replaced and installation of a new disc. The time requirement associated with such replacement adds to the cost and inconvenience of the periodic and necessary change out of rotatable discs.