Patent Description:
An agricultural harvester known as a "combine" is historically termed such because it combines multiple harvesting functions with a single harvesting unit, such as picking, threshing, separating, cleaning, and temporary storage. A combine includes a header which removes the crop from a field, and a feeder housing which transports the crop matter into a threshing drum. The threshing drum rotates within a perforated housing, which may be in the form of adjustable concaves and performs a threshing operation on the crop to remove the grain from the straw. Once the grain is threshed it falls through perforations in the concaves onto a grain pan. From the grain pan the grain is cleaned using a cleaning system, and is then transported to a grain tank onboard the combine. A cleaning fan blows air through the sieves to discharge chaff and other debris, which is also called material other than grain (MOG), toward the rear of the combine. Non-grain crop material such as straw from the threshing section proceeds through a residue system, which may utilize a straw chopper to process the non-grain material and direct it out the rear of the combine. When the grain tank becomes full, the combine is positioned adjacent a vehicle into which the grain is to be unloaded, such as a semi-trailer, chaser bin, straight truck, or the like; and an unloading system on the combine is actuated to transfer the grain into the vehicle.

More particularly, a threshing and separation system includes one or more drums which can extend transversely, in the case of what is known as a "conventional" combine, or axially, in the case of what is known as a "rotary" combine, within the body of the combine, and which are partially or fully surrounded by a perforated concave. The crop material is threshed and separated by the rotation of the drum within the concave. Coarser non-grain crop material such as stalks and leaves are transported to the rear of the combine and discharged back to the field. The separated grain, together with some finer non-grain crop material such as chaff, dust, straw, and other crop residue are discharged through the concaves and fall onto a grain pan where they are transported to a cleaning system. Alternatively, the grain and finer non-grain crop material may also fall directly onto the cleaning system itself.

A cleaning system further separates the grain from non-grain crop material, and typically includes a fan directing an airflow stream upwardly and rearwardly through horizontally arranged sieves which oscillate in a fore and aft manner. The airflow stream lifts and carries the lighter non-grain crop material towards the rear end of the combine for discharge to the field. Clean grain, being heavier, and larger pieces of non-grain crop material, which are not carried away by the airflow stream, fall onto a surface of an upper sieve (also known as a chaffer sieve) where some or all of the clean grain passes through to a lower sieve (also known as a cleaning sieve). Grain and non-grain crop material remaining on the upper and lower sieves are physically separated by the reciprocating action of the sieves as the material moves rearwardly. Any grain and/or non-grain crop material remaining on the top surface of the upper sieve are discharged at the rear of the combine. Grain falling through the lower sieve lands on a bottom pan of the cleaning system, where it is conveyed forwardly toward a clean grain auger.

The clean grain auger conveys the grain to a grain tank for temporary storage. The grain accumulates to the point where the grain tank is full and is discharged to an adjacent vehicle such as a semi trailer, chaser bin, straight truck or the like by an unloading system on the combine that is actuated to transfer grain into the vehicle.

In conventional combines, where the drum extends transversely, the drum has spaced apart rasp bars extending along the width of the drum. The bars rotate in order to contact crop material that has passed through the header and rub the crop material against the concave to thresh and separate the crop material. In some arrangements, the bars are staggered, relative to each other, to balance the weight of the drum during threshing and separation. While this arrangement is effective to thresh and separate crop material, there are certain instances where the drum can become off-balanced.

What is needed in the art is a threshing and separation system that addresses some of the previously described disadvantages of known threshing and separation systems.

Patent publication document <CIT> discloses a threshing drum comprising rasp bars and inwardly curved cover plates.

Patent publication document <CIT> discloses a threshing drum comprising rasp bars and cover plates provided with a driver, which may be in the form of a paddle. On the back side, the cover plates are provided with a reinforcement profile.

The present invention provides a threshing drum for a threshing and separation system of an agricultural harvester includes: a drum frame including at least one drum frame member, the drum frame defining an axis of rotation; a plurality of rasp bars coupled to the drum frame, each of the rasp bars being circumferentially spaced from adjacent rasp bars about the axis of rotation; and a plurality of cover plates coupled to the drum frame, each of the cover plates being disposed between adjacent rasp bars. A crop egress gap is defined between each of the cover plates and an adjacent rasp bar and is sized to allow egress of crop material out from an interior of the drum during rotation of the drum.

In some embodiments, the plurality of rasp bars comprises a first rasp bar and a second rasp bar that extends parallel to the first rasp bar and is circumferentially staggered with the first rasp bar relative to the axis of rotation.

In some embodiments, at least one of the cover plates comprises a first portion comprising a lip that is hooked underneath an adjacent rasp bar. At least one of the cover plates may comprise a second portion opposite the first portion that is connected to the at least one drum frame member. The second portion may be bolted to the at least one drum frame member.

According to the invention, the cover plates comprise an outer surface configured to push crop material against a concave during rotation and an inner surface configured to direct crop material toward the crop egress gaps during rotation. The cover plates comprise an outer portion including the outer surface and an inner portion including the inner surface, the outer portion and the inner portion defining a pocket therebetween.

In some embodiments, the cover plates comprise a first cover plate and a second cover plate that is non-identical to the first cover plate. A first crop egress gap defined between a first rasp bar and the first cover plate may be larger than a second crop egress gap defined between a second rasp bar and the second cover plate.

In some embodiments, all of the rasp bars are at least partially offset with the other rasp bars in a direction that extends parallel to the axis of rotation.

In some embodiments, the at least one drum frame member comprises a plurality of drum frame members and each of the rasp bars are coupled to a pair of adjacent drum frame members.

In some embodiments, the at least one drum frame member is a disk.

In some exemplary embodiments provided according to the present disclosure, a threshing and separation system for an agricultural harvester includes the previously described threshing drum and a concave placed adjacent to the threshing drum such that rotation of the threshing drum rubs material against the concave.

In some exemplary embodiments provided according to the present disclosure, an agricultural harvester includes a chassis carrying the previously described threshing and separation system with the previously described threshing drum.

A potential advantage that may be realized by the exemplary embodiments disclosed herein is that the crop egress gap allows crop material that would normally get trapped inside the drum to egress out of the interior of the drum, reducing the potential for crop buildup in the drum that can cause a weight imbalance.

Another advantage is that the cover plates can be shaped to guide crop material from the interior of the drum to the crop egress gap during rotation to assist with removal of trapped crop material.

Yet another advantage is that incorporating the crop egress gap can increase the yield of crop material by reducing the amount of crop material that gets trapped and spoiled inside the drum.

Yet another advantage is that the overall weight of the drum can be decreased by reducing the amount of trapped crop material, reducing the power requirements to rotate the drum.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one embodiment of the invention, and such exemplification is not to be construed as limiting the scope of the invention in any manner.

The terms "grain", "straw" and "tailings" are used principally throughout this specification for convenience but it is to be understood that these terms are not intended to be limiting. Thus "grain" refers to that part of the crop material which is threshed and separated from the discardable part of the crop material, which is referred to as non-grain crop material, MOG or straw. Incompletely threshed crop material is referred to as "tailings". Also the terms "forward", "rearward", "left" and "right", when used in connection with the agricultural harvester and/or components thereof are usually determined with reference to the direction of forward operative travel of the harvester, but again, they should not be construed as limiting. The terms "longitudinal" and "transverse" are determined with reference to the fore-and-aft direction of the agricultural harvester and are equally not to be construed as limiting.

Referring now to the drawings, and more particularly to <FIG>, a combine harvester, generally indicated at <NUM>, comprises a chassis <NUM>, supported on a fixed front axle <NUM> and an oscillating rear axle (not shown). The combine <NUM> defines a longitudinal axis A1 which extends generally parallel to a travel direction <NUM> of the combine <NUM>. The front axle <NUM> carries a traction gearbox <NUM>, that is drivingly connected to a pair of drive wheels <NUM>, supporting the front portion of the frame <NUM>. The rear axle is supported by a pair of steerable wheels <NUM>. Mounted onto the main frame <NUM> are an operator's platform <NUM>, with an operator's cab <NUM>, a grain tank <NUM>, a threshing and separation system <NUM>, a grain cleaning system <NUM>, and a power plant or engine <NUM>. A conventional grain header <NUM> and straw elevator <NUM> extend forwardly of the main frame <NUM> and are pivotally secured thereto for generally vertical movement, that is controlled by extensible hydraulic cylinders (not shown).

As the combine harvester <NUM> is propelled forwardly over a field with standing crop, the latter is severed from the stubble by a sickle bar <NUM> at the front of the header <NUM> and guided by a reel <NUM> and an auger <NUM> to the straw elevator <NUM>, that supplies the cut crop to the threshing and separation system <NUM>. The crop received therein is threshed and separated, that is to say, the crop is rubbed and beaten, whereby the grain, seed or the like, is loosened and separated from the straw, crop waste or other discardable part of the crop. The combine harvester <NUM>, illustrated in <FIG>, comprises a threshing and separation system <NUM> including a threshing drum <NUM>, a straw beater <NUM> and a separator drum <NUM>, co-operating with a set of respectively adjacent concaves <NUM>, <NUM>, <NUM>. Conventional straw walkers <NUM> are operable, in use, to discharge a mat of remaining crop material (i.e. mainly straw as most grain is separated therefrom) through a straw hood <NUM> to a straw chopper <NUM> that chops the straw and ejects it onto the field.

Grain that has been separated by the threshing and separation system <NUM> falls onto a first grain pan <NUM> of the cleaning system <NUM>, that further also comprises a pre-cleaning sieve <NUM>, positioned above a second grain pan <NUM>, an upper chaffer sieve <NUM> and a lower grain sieve <NUM>, disposed the one above the other behind and below the pre-cleaning sieve <NUM>, and a cleaning fan <NUM>.

The grain pans <NUM>, <NUM> and the sieves <NUM>, <NUM>, <NUM> are oscillated generally back-and-forth for transporting threshed and separated grain from the first grain pan <NUM> to the pre-cleaning sieve <NUM> and the second grain pan <NUM> and therefrom to the sieves <NUM>, <NUM>. The same oscillatory movement spreads the grain across the sieves <NUM>, <NUM>, <NUM>, while permitting the passage of cleaned grain by gravity through the apertures of these sieves. The grain on the sieves <NUM>, <NUM>, <NUM> is subjected to a cleaning action by the fan <NUM> that provides an air flow through the sieves to remove chaff and other impurities such as dust from the grain by making this material airborne for discharge from the machine.

Clean grain falls to a clean grain auger (not shown) in a clean grain auger trough <NUM> and is subsequently transferred by the auger and an elevator mechanism <NUM> to the grain tank <NUM>. Incompletely threshed ears, the so-called "tailings", fall to a tailings auger (not shown) in a tailings auger trough <NUM>. The tailings are transported sideways by this auger to a separate re-thresher <NUM> and returned by a tailings elevator <NUM> to the first grain pan <NUM> for repeated cleaning action.

A pair of grain tank augers <NUM> at the bottom of the grain tank <NUM> is used to urge the clean grain sideways to an unloading tube <NUM>, wherein it is elevated by unloading augers (not shown) for discharge from the harvester <NUM>.

Referring now to <FIG>, an exemplary embodiment of a threshing drum <NUM> for a threshing and separation system <NUM> of an agricultural harvester <NUM> is illustrated. The drum <NUM> includes a drum frame <NUM> including at least one drum frame member <NUM>, illustrated as a plurality of drum frame members <NUM> that are aligned on an axis of rotation AR defined by the drum frame <NUM>. Each of the drum frame members <NUM> may be in the shape of a disk, as illustrated, but it should be appreciated that the drum frame members <NUM> can have other shapes. Rasp bars 203A, 203B are coupled to the drum frame <NUM>, with each of the rasp bars 203A, 203B being circumferentially spaced from adjacent rasp bars 203A, 203B about the axis of rotation AR. As illustrated, the rasp bars 203A, 203B may include first rasp bars 203A and second rasp bars 203B that extend parallel to the first rasp bars 203A but are circumferentially staggered with the first rasp bars 203A relative to the axis of rotation AR. By staggering the rasp bars 203A, 203B, the overall weight balance of the drum <NUM> can be improved. In some embodiments, all of the rasp bars 203A, 203B are at least partially offset with the other rasp bars 203A, 203B in a direction D that extends parallel to the axis of rotation AR, as illustrated in <FIG>, to eliminate increased threshing zones where crop material is threshed harder. When the drum frame <NUM> includes multiple drum frame members <NUM>, each rasp bar 203A, 203B may be coupled to a pair of adjacent drum frame members <NUM>, as illustrated in <FIG>.

In known threshing drums, cover plates are placed between adjacent rasp bars to tightly close the space between adjacent rasp bars, which may be seen in <FIG>. While this is effective to close the space, certain issues have been observed with such a configuration. One particular issue that has been observed is that crop material inevitably ends up becoming trapped in an interior of the drum. The trapped crop material can accumulate to such an amount that the overall weight balance of the drum is disrupted at startup, which adversely affects operation. Further, the trapped crop material can spoil. The most efficient way to remove the trapped crop material from known threshing drums is to remove the cover plates and manually remove the trapped crop material, but this can take a significant amount of time and disrupt harvesting. Thus, removal of trapped crop material in the drum may only be done when convenient, e.g., at the end of a harvest season.

To address some of the previously described issues, and referring now to <FIG>, the threshing drum <NUM> provided according to the present disclosure includes cover plates <NUM>, <NUM>, <NUM> that are disposed between adjacent rasp bars 203A, 203B such that crop egress gaps <NUM>, <NUM>, <NUM> are defined between each of the cover plates <NUM>, <NUM>, <NUM> and an adjacent rasp bar 203A, 203B. The crop egress gaps <NUM>, <NUM>, <NUM> are sized to allow egress of crop material out from an interior of the drum <NUM> during rotation of the drum <NUM> to reduce the likelihood of crop material becoming trapped inside the drum <NUM> and accumulating. Thus, while crop material will inevitably enter the interior of the drum <NUM> during operation, the crop egress gaps <NUM>, <NUM>, <NUM> provide an egress for the crop material to be pushed out of the interior of the drum <NUM> during rotation due to centrifugal forces and join the mat of crop outside the drum <NUM>.

Referring now to <FIG>, a sectional side view of the drum <NUM> is illustrated to show how one of the cover plates <NUM> is coupled to the drum frame <NUM>. While the cover plate <NUM> is illustrated in <FIG>, it should be appreciated that the cover plates <NUM> and <NUM> can be coupled to the drum frame <NUM> in a similar manner. The cover plate <NUM>, by itself, is illustrated in <FIG>. The cover plate <NUM> may include a first portion 401A that has a lip <NUM>. The lip <NUM>, as illustrated in <FIG>, is hooked underneath an adjacent rasp bar 203A to support the first portion 401A of the cover plate <NUM>. A second portion 401B of the cover plate <NUM>, which is opposite the first portion 401A, may be coupled to one or more of the drum frame members <NUM>. The second portion 401B may be, for example, bolted to two of the drum frame members <NUM>, as illustrated in <FIG> and <FIG>. The first portion 401A and the second portion 401B may each be, for example, flanges. Coupling the cover plates <NUM>, <NUM>, <NUM> to the drum frame <NUM> in this manner is easy and convenient, allowing an operator to quickly remove the cover plates <NUM>, <NUM>, <NUM> when desired.

With further reference to <FIG>, and referring to <FIG> as well, it is illustrated that the cover plate <NUM> has an outer surface <NUM> that is on the exterior of the drum <NUM> when mounted and an inner surface <NUM> that is on the interior of the drum <NUM> when mounted. The outer surface <NUM> is configured to push crop material against the concave <NUM> during rotation of the drum <NUM> to thresh and separate the crop material. The inner surface <NUM>, on the other hand, is configured to direct crop material toward the crop egress gap <NUM> during rotation. By directing crop material toward the crop egress gap <NUM>, the inner surface <NUM> assists in removing trapped crop material from the interior of the drum <NUM> to reduce crop material accumulation inside the drum <NUM>.

The outer surface <NUM> may be part of an outer portion <NUM> of the cover plate <NUM>. The outer portion <NUM> of the cover plate <NUM> may include a plurality of connected planar surfaces 406A, 406B, 406C that connect the first portion 401A to the second portion 401B. The planar surfaces 406A, 406B, 406C may each have a different width, relative to each other, so each of the surfaces 406A, 406B, 406C has a different surface area. The dimensions and orientations of the planar surfaces 406A, 406B, 406C may be adjusted, as desired, to direct crop material toward the concave <NUM> during rotation so the crop material may be threshed and separated. For example, the dimensions and orientations of the planar surfaces 406A, 406B, 406C may be adjusted to account for different crop materials being processed, e.g., the dimensions and orientations of the planar surfaces 406A, 406B, 406C may be different when corn is processed compared to when wheat is processed. It should thus be appreciated that the outer portion <NUM> may be adjusted in a variety of ways.

The inner surface <NUM> may be part of an inner portion <NUM> of the cover plate <NUM>. The inner portion <NUM> may include a pair of converging surfaces 408A, 408B that each have a respective terminal portion 409A, 409B connected to the first portion 401A and the second portion 401B, respectively, of the cover plate <NUM>. The surfaces 408A, 408B may have similar widths. The dimensions and orientations of the converging surfaces 408A, 408B may be adjusted, as desired, to direct crop material in the interior of the drum <NUM> toward the crop egress gap <NUM> due to centrifugal forces that arise during rotation, as previously described. For example, the dimensions and orientations of the converging surfaces 408A, 408B may be adjusted to account for different crop materials being processed, e.g., the dimensions and orientations of the converging surfaces 408A, 408B may be different when corn is processed compared to when wheat is processed. Further, the inner portion <NUM> and the outer portion <NUM> of the cover plate <NUM> are spaced apart from one another to form a pocket <NUM> therebetween. By forming the outer surface <NUM> on the outer portion <NUM> and the inner surface <NUM> on the inner portion <NUM>, which is spaced apart from the outer portion <NUM>, the crop material directing behavior of each of the surfaces <NUM>, <NUM> can be independently tuned to provide the desired directing behavior for each surface <NUM>, <NUM>.

Referring now to <FIG>, the other cover plates <NUM> and <NUM> are illustrated. The cover plate <NUM> is illustrated in <FIG> and the cover plate <NUM> is illustrated in <FIG>. As illustrated, the cover plates <NUM> and <NUM> are similar to the cover plate <NUM> in that each of the cover plates <NUM>, <NUM> includes a respective outer surface <NUM>, <NUM> that is configured to direct crop material toward the concave <NUM> during rotation and a respective inner surface <NUM>, <NUM> that is configured to direct crop material toward a respective crop egress gap <NUM>, <NUM> during rotation. The outer surfaces <NUM>, <NUM> may be part of a respective outer portion <NUM>, <NUM> and the inner surfaces <NUM>, <NUM> may be part of a respective inner portion <NUM>, <NUM> with pockets <NUM>, <NUM> formed between the outer portions <NUM>, <NUM> and the inner portions <NUM>, <NUM>, similar to the cover plate <NUM>. Unlike the cover plate <NUM>, each of the cover plates <NUM>, <NUM> may have a discontinuous second portion <NUM>, <NUM> that couples to the drum frame member(s) <NUM>. As illustrated in <FIG>, for example, the cover plates <NUM> may have a recessed region <NUM> of the second portion <NUM> that is radially recessed in relation to the rest of the second portion <NUM> and coupled to one of the drum frame members <NUM>. The recessed region <NUM> may be, for example, located on a front of the cover plate <NUM> when mounted to the drum frame <NUM>. Similarly, as illustrated in <FIG>, the cover plates <NUM> may also have a recessed region <NUM> of the second portion <NUM> that is radially recessed in relation to the rest of the second portion <NUM> and coupled to one of the drum frame members <NUM>. Unlike the recessed region <NUM> of the cover plate <NUM>, the recessed region <NUM> of the cover plate <NUM> may be located on a rear of the cover plate <NUM> when mounted to the drum frame <NUM>.

As can be appreciated from comparing the cover plates <NUM>, <NUM>, <NUM> illustrated in <FIG>, the cover plates <NUM>, <NUM>, <NUM> may be non-identical. The cover plates <NUM> and <NUM> may, for example, have a greater overall width than the cover plates <NUM> due to the distance between the outermost drum frame members <NUM> being greater than the distance between the innermost drum frame members <NUM>. In some embodiments, the crop egress gaps <NUM>, <NUM>, <NUM> may be similar, i.e., a distance between the rasp bars 203A, 203B and an edge of the cover plates <NUM>, <NUM>, <NUM> is similar. Alternatively, the crop egress gaps <NUM>, <NUM>, <NUM> may be different. For example, the crop egress gaps <NUM>, <NUM> between the cover plates <NUM>, <NUM> and the rasp bars 203A, 203B may be larger than the crop egress gap <NUM> between the cover plates <NUM> and the rasp bars 203A, 203B. In other words, the crop egress gaps <NUM> between the cover plates <NUM> and the rasp bars 203A, 203B may be smaller than the crop egress gaps <NUM>, <NUM>. In some embodiments, the crop egress gaps <NUM> between the cover plates <NUM> and the rasp bars 203A, 203B may be the largest of the cross egress gaps <NUM>, <NUM>, <NUM> due to the crop egress gaps <NUM> being closer to a front of the drum <NUM> where crop material is still relatively unthreshed and unseparated, and thus larger in size.

Claim 1:
A threshing drum (<NUM>) for a threshing and separation system (<NUM>) of an agricultural harvester (<NUM>), comprising:
a drum frame (<NUM>) comprising at least one drum frame member (<NUM>), the drum frame defining an axis of rotation (AR);
a plurality of rasp bars (203A, 203B) coupled to the drum frame (<NUM>), each of the rasp bars (203A, 203B) being circumferentially spaced from adjacent rasp bars (203A, 203B) about the axis of rotation (AR); and
a plurality of cover plates (<NUM>, <NUM>, <NUM>) coupled to the drum frame (<NUM>), each of the cover plates (<NUM>, <NUM>, <NUM>) being disposed between adjacent rasp bars (203A, 203B);
wherein a crop egress gap (<NUM>, <NUM>, <NUM>) is defined between each of the cover plates (<NUM>, <NUM>, <NUM>) and an adjacent rasp bar (203A, 203B) and is sized to allow egress of crop material out from an interior of the drum (<NUM>) during rotation of the drum (<NUM>),
characterized in that
- the cover plates (<NUM>, <NUM>, <NUM>) comprise an outer surface (<NUM>, <NUM>, <NUM>) configured to push crop material against a concave (<NUM>) during rotation and an inner surface (<NUM>, <NUM>, <NUM>) configured to direct crop material toward the crop egress gaps (<NUM>, <NUM>, <NUM>) during rotation,
- the cover plates (<NUM>, <NUM>, <NUM>) comprise an outer portion (<NUM>, <NUM>, <NUM>) comprising the outer surface (<NUM>, <NUM>, <NUM>) and an inner portion (<NUM>, <NUM>, <NUM>) comprising the inner surface (<NUM>, <NUM>, <NUM>), the outer portion (<NUM>, <NUM>, <NUM>) and the inner portion (<NUM>, <NUM>, <NUM>) defining a pocket (<NUM>, <NUM>, <NUM>) therebetween.