Agricultural tool unit for rapid conversion of a combination seed drill having a trailed or fine-grain seed dispenser to an on-demand supply system and vice versa

The invention relates to an agricultural tool unit for the rapid conversion of a seed drill having a trailed or fine-grain seed dispenser with volumetric supply to an on-demand supply system and vice versa, which includes at least one hopper containing a granular feed material, such as grains, seeds or agrochemical granules, and a delivery device arranged under the hopper. This device has a structure that consists of two physically defined areas. One of the areas, hereinafter referred to as the "seed box", has a direct connection to the hopper, receiving the granular material from same, generally gravity-fed, and another area, hereinafter referred to as the "air box", which has a connection to an air source such as a fan or similar. The seed box is formed by side walls that define its width, a lower bottom wall, a rear wall with the air inlet from the fan, and a front wall that comprises at least the passage for the seed leading to the area where the trailing rotor is located for fine-grain work, or to the area where the retaining slope is located for on-demand supply.