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EP-4494448-B1 - STRAW CHOPPER COUNTER KNIFE BAR WITH BLADE BETWEEN CONCAVE AND KNIFE BAR PIVOT

EP4494448B1EP 4494448 B1EP4494448 B1EP 4494448B1EP-4494448-B1

Inventors

  • LINDE, COOPER
  • Fjeld, Garrett
  • ISAAC, NATHAN E.

Dates

Publication Date
20260506
Application Date
20240328

Claims (12)

  1. An agricultural residue chopper assembly comprising: a cutting chamber housing (120) defining a cutting chamber (122) therein; a plurality of cutting knives (126) mounted to rotate along a cutting direction (R) within the cutting chamber about a cutting knife rotation axis (124'); a counterknife shaft unit mounted at a fixed location relative to an outer surface (120') of the cutting chamber housing (120), wherein the counterknife shaft unit is rotatable about a counterknife shaft rotation axis (136) through a range of motion between a first position and a second position, and wherein the counterknife shaft rotation axis (136) extends parallel to the cutting knife rotation axis (124'); an outer face (138) defined by a portion of the counterknife shaft unit; one or more counterknives (134) secured to the counterknife shaft unit and extending radially outward from the outer face (138), wherein the one or more counterknives (134) are spaced a first distance from the cutting knife rotation axis (124') when the counterknife shaft unit is in the first position, and a second distance from the cutting knife rotation axis (124') when the counterknife shaft unit is in the second position, and the second distance is less than the first distance; characterized in that : the outer face (138) and the outer surface (120') of the cutting chamber housing (120) define a trailing area (A) located between a first line (L1) extending between the cutting knife rotation axis (124') and the counterknife shaft rotation axis (136), and a second line (L2) that is parallel to the first line (L1) and spaced from the first line (L1) along a tangent to the cutting direction (R), and the outer face (138) is configured such that a gap distance (G), as measured parallel to the first line (L1), between the outer face (138) and the outer surface (120') of the cutting chamber housing (120) at all locations within the trailing area (A) remains constant or increases in size as the counterknife shaft unit is rotated from the first position to the second position.
  2. The agricultural residue chopper assembly according to any of the preceding claims, wherein at least a portion of the one or more counterknives (134) is located directly between the counterknife shaft rotation axis (136) and the cutting knife rotation axis (124') when the counterknife shaft unit is in the extended position.
  3. The agricultural residue chopper assembly according to any of the preceding claims, wherein a leading portion (140) of the outer face (138) is located on an upstream side of the first line (L1) relative to the cutting direction (R) when the counterknife shaft unit is in the first position, and the leading portion (140) extends inward from the outer face (138) towards the counterknife shaft axis to define a residue pushing surface (140').
  4. The agricultural residue chopper assembly of claim 3, wherein the residue pushing surface (140') comprises a concave face.
  5. The agricultural residue chopper assembly according to any of the preceding claims, wherein a portion of the outer face (138) located in the trailing area (A) throughout the range of motion is semicircular and concentric with the counterknife shaft rotation axis (136).
  6. The agricultural residue chopper assembly according to any of the preceding claims, wherein the one or more counterknives (134) are completely outside the cutting chamber when the counterknife shaft unit is in the first position.
  7. The agricultural residue chopper assembly according to any of the preceding claims, wherein the cutting chamber housing (120) comprises a counterknife slot (146) configured to receive one of the one or more counterknives (134) located directly between the counterknife shaft rotation axis (136) and the cutting knife rotation axis (124') when the counterknife shaft unit is in the second position.
  8. The agricultural residue chopper assembly according to any of the preceding claims, wherein the counterknife shaft unit comprises: a counterknife shaft (128); and at least one knife holder (132) connected to and extending radially from the counterknife shaft (128); wherein the outer face (138) is defined by the at least one knife holder (132).
  9. The agricultural residue chopper assembly according to any of the preceding claims, wherein the counterknife shaft unit comprises: a counterknife shaft (128); and a plurality of knife holders (132) connected to and extending radially from the counterknife shaft (128) and spaced along the counterknife shaft rotation axis (136); wherein each of the plurality of knife holders (132) comprises a respective portion of a collective outer face (138).
  10. The agricultural residue chopper assembly according to any of the preceding claims, further comprising an overload breakaway connection (154, 156) joining the one or more counterknives (134) to the counterknife shaft unit.
  11. An agricultural harvester machine (100) comprising: a chassis (102) configured for movement on a surface; and a residue chopper (116) comprising the agricultural residue chopper assembly according to any of the preceding claims.
  12. The agricultural harvester machine of claim 11, further comprising: a threshing and separating system (108) attached to the chassis (102) and configured to deliver crop residue to the residue chopper (116); and powered wheels (104) configured to move the chassis (102) on the surface.

Description

BACKGROUND OF THE INVENTION Agricultural machines, such as combine harvesters, typically process crop material, and deposit a portion of the material on the ground behind the machine. As the purpose of the harvester is to collect grain, the material that is deposited is primarily material other than grain ("MoG"), such as chaff and stalks. This is commonly called "residue." It is generally desirable to minimize the size of the residue pieces, and to spread the residue evenly across the path of the machine. For this purpose, the machine may include a chopper to reduce the residue size, and a spreader to distribute the residue. The chopper typically comprises a series of knives that rotate on a shaft and are partially enclosed by a shroud that forms a chopper housing. The residue enters the shroud, and the knives strike and cut the residue. A typical chopper also has counterknives that extend radially towards the shaft, and between adjacent pairs of the rotating knives. The counterknives face towards the incoming stream of residue, and provide additional cutting edges. The counterknives can be mounted on their own shaft or on a support that can be moved to extend and retract the counterknives. Typical counterknives are positioned below the chopper housing, such as below a concave pan assembly that forms the bottom part of the chopper housing. Examples of such devices are shown in United States Patent Nos. 7,484,350, 7,677,965, and 8,141,805. The counterknives are mounted on a pivoting support that is rotated to move the counterknife blades up to enter the chopper housing. In this arrangement, the pivot axis is located forward of the blades, and the blades trail behind the pivot axis with respect to the flow direction of the residue. The blades are mounted to a plate that extends generally radially and backwards from the pivot axis, with the counterknife blades oriented generally tangentially to the pivot axis. Having the counterknives spaced behind the pivot axis is helpful to minimize changes in the orientation of the counterknives as they enter the chopper housing. In particular, it can be desirable to maintain the counterknives' leading edges at a particular range of angles relative to the rotating chopper knives, to thereby maintain ideal chopping effectiveness and efficiency. The angle or range of angles between the counterknives and the chopper knives can also be maintained by mounting the counterknives along a linear sliding path to enter and exit the chopper housing. While such rotating and sliding arrangements can be effective, it has been found that residue can become trapped between the outer face of the chopper pan and the plate or other structure to which the counterknives are mounted. Residue can also become trapped in a gap formed between the counterknives and the outer face of the chopper pan while the counterknives are in the retracted position. Such residue is compressed as the counterknife assembly is moved into the extended position. This can lead to increased operating power requirements, frequent servicing requirements, and possible damage to the parts. Known agricultural residue chopper assemblies are disclosed in documents US 2017/099771 A1, EP 2 000 019 B1, US 2009/111549 A1 and CN 105 101 779 A. The inventors have determined that further improvements can be made to agricultural machine counterknife assemblies. This description of the background is provided to assist with an understanding of the following explanations of exemplary embodiments, and is not an admission that any or all of this background information is necessarily prior art. SUMMARY OF THE INVENTION An agricultural residue chopper assembly comprising: a cutting chamber housing defining a cutting chamber therein; a plurality of cutting knives mounted to rotate along a cutting direction within the cutting chamber about a cutting knife rotation axis; a counterknife shaft unit mounted at a fixed location relative to an outer surface of the cutting chamber housing, wherein the counterknife shaft unit is rotatable about a counterknife shaft rotation axis through a range of motion between a first position and a second position, and wherein the counterknife shaft rotation axis extends parallel to the cutting knife rotation axis; an outer face defined by a portion of the counterknife shaft unit; one or more counterknives secured to the counterknife shaft unit and extending radially outward from the outer face, wherein the one or more counterknives are spaced a first distance from the cutting knife rotation axis when the counterknife shaft unit is in the first position, and a second distance from the cutting knife rotation axis when the counterknife shaft unit is in the second position, and the second distance is less than the first distance. The outer face and the outer surface of the cutting chamber housing define a trailing area located between a first line extending between the cutting knife rotation axis and the counterknife