Combine chaffer with chaffer dam

1. A cleaning system for an agricultural combine, comprising:

a cleaning shoe including a chaffer vertically spaced over an underlying grain sieve and having an upstream extremity and a downstream extremity;

a cleaning fan for establishing a flow of air upwardly through the chaffer; and

a transverse chaffer dam mounted proximate to and extending upwardly relative to the downstream extremity transversely obstructing a crop layer flow path extending over the chaffer from the upstream extremity to the downstream extremity while permitting air and threshed crop material to flow thereover and thereunder through a transverse opening between the chaffer dam and the downstream extremity.

2. The cleaning system according to claim 1 , wherein the chaffer dam is longitudinally straight and perpendicular to the crop layer flow path.

3. The cleaning system according to claim 1 , wherein the chaffer dam is mounted directly to the chaffer.

4. The cleaning system according to claim 1 , wherein the chaffer additionally comprises a first side and a second side extending between the upstream extremity and the downstream extremity, and the transverse opening extends between a first end of the chaffer dam proximate to the first side of the chaffer and a second end of the chaffer dam proximate to the second side of the chaffer.

5. A cleaning system for an agricultural combine, comprising:

a cleaning shoe including a chaffer vertically spaced over an underlying grain sieve and having a first side and a second side extending between an upstream extremity and a downstream extremity;

a cleaning fan for establishing a flow of air upwardly through the chaffer; and

a chaffer dam proximate to and extending upwardly relative to the downstream extremity and extending transversely from a first end mounted to the first side of the chaffer to a second end mounted to the second side of the chaffer, the chaffer dam transversely obstructing a crop layer flow path extending over the chaffer from the upstream extremity to the downstream extremity while permitting air and threshed crop material to flow thereover and thereunder through a an opening between the chaffer dam and the downstream extremity and that extends transversely between the first end of the chaffer dam and the second end of the chaffer dam.

6. The cleaning system according to claim 5 , wherein the chaffer dam is longitudinally straight and perpendicular to the crop layer flow path between the first end and the second end.

7. In a cleaning system for an agricultural combine comprising a cleaning shoe including a chaffer vertically spaced over an underlying grain sieve and having a upstream extremity and a downstream extremity, and a cleaning fan for establishing a flow of air upwardly through the chaffer, a method comprising mounting a chaffer dam transversely proximate to and extending upwardly relative to the downstream extremity, the chaffer dam transversely obstructing a crop layer flow path extending over the chaffer from the upstream extremity to the downstream extremity while permitting air and threshed crop material to flow thereover and thereunder through a transverse opening between the chaffer dam and the downstream extremity.

8. The method according to claim 7 , wherein the chaffer dam is longitudinally straight and perpendicular to the crop layer flow path.

9. The method according to claim 7 , wherein the step of mounting the chaffer dam comprises mounting the chaffer dam directly to the chaffer.

10. The method according to claim 7 , wherein the chaffer additionally comprises a first side and a second side extending between the upstream extremity and the downstream extremity, and the transverse opening extends between a first end of the chaffer dam proximate to the first side of the chaffer and a second end of the chaffer dam proximate to the second side of the chaffer.

11. In a cleaning system for an agricultural combine comprising a cleaning shoe including a chaffer vertically spaced over an underlying grain sieve and having a first side and a second side extending between an upstream extremity and a downstream extremity, and a cleaning fan for establishing a flow of air upwardly through the chaffer, a method comprising transversely extending a chaffer dam proximate to and extending upwardly relative to the downstream extremity from a first end of the chaffer dam proximate to the first side of the chaffer to a second end of the chaffer dam proximate to the second side of the chaffer, the chaffer dam transversely obstructing a crop layer flow path extending over the chaffer from the upstream extremity to the downstream extremity while permitting air and threshed crop material to flow thereover and thereunder through an opening between the chaffer dam and the downstream extremity and that extends transversely between the first end of the chaffer dam and the second end of the chaffer dam.

12. The method according to claim 11 , wherein the step of transversely extending the chaffer additionally comprises mounting the first end of the chaffer dam to the first side of the chaffer and mounting the second end of the chaffer to the second side of the chaffer.

13. The method according to claim 11 , wherein the chaffer dam is longitudinally straight and perpendicular to the crop layer flow path between the first and second end.