Conveyor roller set and harvesting machine

1. A conveyor roller set for an agricultural machine comprising a front aperture for receiving harvested material from a header, the conveyor roller set comprising:

at least one upper roller; and

at least one lower roller disposed in the header,

wherein the at least one upper roller includes a first upper conveyor roller with a diameter greater than a diameter of the at least one lower conveyor roller, and

wherein the first upper conveyor roller is close to a last conveyor roller of the header thereby eliminating a space regardless of an inclination of a frame of the header.

2. The conveyor roller set according to claim 1 , wherein the at least one upper roller comprises a plurality of upper rollers, and wherein the at least one lower roller comprises a plurality of lower rollers, wherein the first upper conveyor roller has a diameter greater than diameters of the plurality of upper rollers and the plurality of lower rollers.

3. The conveyor roller set according to claim 2 , wherein the plurality of upper rollers are floatingly mounted through apertures, including an aperture responsible for a floating support of the first upper conveyor roller with an angular configuration discordant from a flow of the harvested material.

4. The conveyor roller set according to claim 3 , wherein the apertures have a wedge configuration.

5. The conveyor roller set according to claim 1 , wherein the first upper conveyor roller comprises a diameter which is 35 to 55% greater than a diameter of the at least one lower roller.

6. The conveyor roller set according to claim 5 , wherein the diameter of the first upper conveyor roller is approximately 46% greater than the diameter of the at least one lower conveyor roller.

7. The conveyor roller set according to claim 1 , wherein diameters of the at least one upper and the at least one lower rollers and a diameter of the first upper conveyor roller have a ratio of 1:1.4.

8. The conveyor roller set according to claim 1 , wherein the first upper conveyor roller comprises a diameter around 306 mm, and the at least one lower roller comprises a diameter around 210 mm.

9. The conveyor roller set according to claim 1 , wherein the upper and lower rollers are mounted directly on a chassis of the agricultural machine.

10. The conveyor roller set according to claim 1 , wherein the upper and lower rollers are mounted in an independent module which is to be connected to the agricultural machine.

11. A harvesting machine comprising:

a self-propelled structure configured to move forward on a ground surface and including a front end and a cavity behind it defining an inlet aperture;

a billet cutter configured to cut stalks or canes into billets;

an upwardly and rearwardly extending lift conveyor, loaded in the frame and configured to convey the cut stalks or canes to the billet cutter; and

a conveyor roller set disposed in the cavity defined between the inlet aperture and the lift conveyor, the conveyor roller set configured to transport a flow of harvested stalks, to gather the harvested stalks into a bundle, and to transport the bundle to the lift conveyor, to be transported to the billet cutter, the conveyor roller set including:

at least one upper roller; and

at least one lower roller disposed in the aperture of the agricultural machine,

wherein the at least one upper roller includes a first upper conveyor roller which has a diameter greater than a diameter of the at least one lower roller, and

wherein the first upper conveyor roller is close to a last conveyor roller of a header thereby eliminating a space at the inlet aperture.

12. The harvesting machine according to claim 11 , wherein the harvesting machine is adapted for harvesting sugarcane or sweet sorghum.