Torsional stiffness transfer mechanism for a hinged harvester head

An agricultural vehicle header having a center section, a wing section, a hinge connecting the center section's lower frame to the wing section's lower frame, and a torque transfer linkage connecting the center section's upper frame to the wing section's upper frame. The torque transfer link has a first link, a second link, a first pivot connection joining the first link to the center section upper frame, and providing a respective single degree of rotational freedom between the first link and the center section upper frame, a second pivot connection joining the first link to the second link, and providing a respective single degree of rotational freedom between the first link and the second link, and a third pivot connection joining the second link to the first wing section upper frame, and providing a respective single degree of rotational freedom between the second link and the first wing section frame.

BACKGROUND OF THE INVENTION

Agricultural equipment, such as combines, swathers and windrowers, typically include a header that is movably attached to the chassis of the vehicle. During operation, the header might be raised or lowered to account for variations in the ground level, properties of the particular crop being harvested, and various other operating conditions. The header typically is located at the front of the vehicle, and extends laterally relative to the vehicle's forward direction of travel. In some cases, the header is a single rigid body. In other cases the header is a so-called multi-segment or articulated header comprising multiple sections that are movable relative to each other. For example, the header may have a center section located along the vehicle fore-aft centerline, and a wing section attached at, and extending laterally from, each lateral end of the center section. Devices such as hydraulic or pneumatic cylinders, mechanical linkages, and the like, may be provided to selectively control the heights of the center section and the wing sections.

Headers are often designed to follow the contours of the crop field to cut the crops at a uniform height across the width of the header. To this end, the cutter bar of the header may be mounted on flexible forward-extending arms that allow the cutter bar to raise and lower according to the local ground level. Furthermore, in multi-segment headers, the wing sections are able to pivot up and down relative to the center section to obtain even more ground-following capability.

While ground-following is desirable, relatively wide harvester headers, particularly multi-segment headers, can experience significant deflection due to the weight of the header. This deflection can potentially impair proper operation of the header during transport by allowing the ends of the header to droop closer to nearby objects. Such deflection can also affect harvesting performance by allowing more plant material to enter the header at the ends, leading to unnecessary power consumption, and by rotating forward to increase the likelihood of plowing dirt. Furthermore, if it is necessary to raise the center section to prevent the ends from drooping too far, the center section may not be vertically situated to harvest all of the crop. This deflection is also sometimes perceived as giving an undesirable appearance to the header, which can lead to customer dissatisfaction or rejection of the header in favor of other options, even if the deflection has minimal effect on the header's performance.

Header deflection can be reduced by making the parts stiffer, but this can lead to excessive weight. Thus, header design requires an optimization of stiffness and weight. It has been found that this optimization is even more difficult in multi-segment headers, which typically have a single hinge connection joining the center section to the wing sections. The hinge can be reinforced to help prevent deflection, but doing so is likely to require the hinge to become excessively robust to obtain even minor improvements. Thus, there remains a need to advance the state of the art.

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

In one exemplary aspect, there is provided an agricultural vehicle header having a center section having a center section upper frame and a center section lower frame, a first wing section having a first wing section upper frame and a first wing section lower frame, a first hinge connecting the center section lower frame to the first wing section lower frame, and a first torque transfer linkage connecting the center section upper frame to the first wing section upper frame. The first torque transfer link has a first link, a second link, a first pivot connection joining the first link to the center section upper frame, and providing a respective single degree of rotational freedom between the first link and the center section upper frame, a second pivot connection joining the first link to the second link, and providing a respective single degree of rotational freedom between the first link and the second link, and a third pivot connection joining the second link to the first wing section upper frame, and providing a respective single degree of rotational freedom between the second link and the first wing section frame.

In some exemplary aspects, one or more of the first pivot connection, the second pivot connection and the third pivot connection comprises a double-shear pivot connection.

In some exemplary aspects, the first pivot connection, the second pivot connection and the third pivot connection all comprise respective double-shear pivot connections.

In some exemplary aspects, the second pivot connection is positioned lower than the first pivot connection and the third pivot connection when the header is configured for use.

In some exemplary aspects, the first hinge is configured to allow the first wing section to rotate relative to the center section about a pivot axis, and the respective single degrees of rotational freedom of the first pivot connection, the second pivot connection and the third pivot connection are parallel with the pivot axis.

In some exemplary aspects, the first link comprises: a first link arm extending from the first pivot connection to the second pivot connection, a second link arm extending from the first pivot connection to the second pivot connection, the second link arm being spaced from the first link arm, and a link body joining the first link arm to the second link arm.

In some exemplary aspects, the first link comprises a first clevis at the first pivot connection, and a second clevis at the second pivot connection, and the second link comprises a third clevis at the third pivot connection.

In some exemplary aspects, the second link comprises a clevis at the second pivot connection.

In some exemplary aspects, the header further includes: a second wing section having a second wing section upper frame and a second wing section lower frame, a second hinge connecting the center section lower frame to the second wing section lower frame, and a second torque transfer linkage connecting the center section upper frame to the second wing section upper frame. The second torque transfer link has a respective first link, a respective second link, a respective first pivot connection joining the respective first link to the center section upper frame, and providing a respective single degree of rotational freedom between the first link and the center section upper frame, a respective second pivot connection joining the respective first link to the respective second link, and providing a respective single degree of rotational freedom between the respective first link and the respective second link, and a respective third pivot connection joining the respective second link to the second wing section upper frame, and providing a respective single degree of rotational freedom between the respective second link and the second wing section frame.

In any of the foregoing embodiments, the header may be part of an agricultural vehicle having a chassis configured for movement on a surface. The vehicle may include a threshing and separating system mounted to the chassis, and the center section may be operatively connected to the threshing and separating system by a feeder housing.

In the figures, like reference numerals refer to the same or similar elements.

DETAILED DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention provide apparatus for improving the torsional stiffness of multi-segment headers for agricultural equipment, such as combines, swathers, windrowers, and the like. It will be appreciated that other embodiments may be used in other types of machines having a similar arrangement of parts, upon incorporation of the appropriate features of the inventions herein.

FIG. 1illustrates an example of an agricultural combine100with which embodiments of the invention may be used. The combine100includes a chassis102that is configured for driving on a surface (e.g., the ground or a road), such as by being supported by pneumatic wheels104, tracked wheel assemblies, or the like. The combine100includes a threshing and separating system106mounted on or within the chassis102. The threshing and separating system106may include mechanisms such as one or more threshers (e.g., an axial flow thresher), sieves, blowers, and the like, as well as an associated grain hopper and unloader. Threshing and separating systems106and their associated components are well-known in the art, and need not be described in detail herein. The combine100also may include other features, such as a spreader108, an operator cab110, and so on.

Referring also toFIG. 2, the combine100also includes a header112, which is configured to cut and harvest crop material from the ground as the combine100drives in the forward direction F. For example, the header112may include one or more cutter bars114located at or near the leading edge of the header112to cut crops at or near the ground level, and one or more reels116configured to pull the crop material backwards towards the header112. The header112also may include crop conveyors118that are configured to move the crop material at the lateral ends of the header112towards the center of the header112. The crop conveyors118may be in the form of belts, auger screws, or the like. At the center, the header112may include a feeder conveyor120that conveys the crop material backwards towards a crop outlet122. The header112also may include gauge wheels124or skids to control the height of the header112over the ground.

The header112is built on a frame126, which is attached to the chassis102by a feeder housing128. The feeder housing128is configured to convey crop material backwards from the header112to the threshing and separating system106. The feeder housing128may be movable by one or more actuators130to change the position of the header112relative to the ground.

FIG. 3illustrates the construction of a conventional multi-segment, or “articulated,” header300having a center section302that extends laterally from a first end to a second end, and left and right wing sections304extending laterally away from the center section302from respective ends of the center section302. The term “lateral” will be understood to mean a direction that is transverse to the forward drive direction F. The header300typically is mounted to a forward end of the chassis102, such as shown inFIG. 1, but it may be mounted elsewhere (e.g., at the rear or at some intermediate location under the chassis102). The shown example has two wing sections304, but other embodiments may have a single wing section304.

The center section302is constructed on a frame assembly having an upper frame306and a lower frame308. The upper frame306and lower frame308may be connected by frame uprights310or the like to form the frame assembly. Similarly, each wing section304is constructed on a frame assembly having an upper frame312and a lower frame314, with uprights316therebetween.

Each wing section304is movably mounted to the center section302by a respective hinge318. The hinges318extend generally in the forward direction F, but the particular orientation can change depending on the orientation of the header112relative to the chassis102. This type of prior art multi-segment header is subject to relatively significant deflection. In particular, the weight of the wing sections304and the center section302cause the lateral ends of the wing sections304to droop towards the ground. Furthermore, the center of gravity of the center section302and wing sections304is located forward of the main structural body of the frame, and thus the center section302and wing sections304also droop down in the forward direction. The forward droop at the ends of the wing sections304is particularly exacerbated by the hinges318, which are unable to transmit the torsional stiffness of the upper frames of the wing and center sections. The discontinuity in torsional stiffness at the hinges318manifests as a relatively sudden increase in forward droop at the inboard ends of the wing sections.

The inventor has determined that the total amount of droop at the wing sections can be reduced by providing an additional torque transfer mechanism at the hinge locations.FIGS. 4-6show an example of such a mechanism.

FIG. 4shows a multi-segment header400with various parts removed to show the main structural components. The header400has a center section402having a center section upper frame404and a center section lower frame406. The center section upper frame404and lower frame406are illustrated as beams that are spaced apart in the vertical direction and joined by uprights408. The upper frame404and lower frame406may also be joined by stressed panels, diagonal braces, and other structural components. It will also be appreciated that the upper frame404and lower frame406may comprise portions of a unitary structure, such as a single large extrusion, casting, a monocoque-type construction of stamped and welded parts, or the like.

A wing section410is attached at each end of the center section402, but other embodiments may include a single wing section410attached at one end of the center section402. Each wing section has a wing section upper frame412and a wing section lower frame414. As with the center section, the wing section upper frame412and lower frame414may be separate beams that are joined by uprights416, panels, diagonal braces, or the like. The wing section upper frame412and lower frame414also may comprise portions of a single extrusion, casting, unitary monocoque-type assembly, or the like.

A hinge418connects the lower frame414of each wing section410to the lower frame406of the center section402. The hinges418may comprise any suitable pivoting connector, such as a pin or the like. For example, as best shown inFIG. 5, the center section lower frame406may have a first clevis500formed by spaced plates having aligned circular openings, and the wing section lower frame414may have a second clevis502formed by spaced plates having aligned circular openings, and one or more pins504may be inserted through the clevis openings to form a pivoting hinge418. Each hinge418is configured to allow the respective wing section410to pivot relative to the center section402about a respective pivot axis506. The hinges418may define respective pivot axes506that are parallel to each other, but this is not strictly required. The pivot axis506is oriented generally in the forward direction F, but the exact orientation will change as the header400is moved relative to the combine chassis102.

A torque transfer linkage420connects the center section upper frame404to each wing section upper frame412. The torque transfer linkage420includes a first link508, a second link510, a first pivot connection512joining the first link508to the center section upper frame404, a second pivot connection514joining the first link508to the second link510, and a third pivot connection516joining the second link510to the wing section upper frame412. Each pivot connection512,514,516provides a single degree of rotational freedom between the joined parts. Thus, the first link508is constrained to pivot about a single axis relative to the center section upper frame404at the first pivot connection512. Similarly, the second link510is constrained to pivot about a single axis relative to the wing section upper frame412at the third pivot connection516. The second pivot connection514allows the first link508and second link510to pivot relative to one another about a single axis at the second pivot connection514. Each pivot connection512,514,516may comprise any suitable configuration of pins, bores, bearings, bushings, or the like.

As shown inFIGS. 4-6, the first link508and second link510are angled relative to one another when the wing section410is in an intermediate position (i.e., between the fully-lowered and fully-raised use positions). Thus, the torque transfer linkage420is able to collapse and extend to allow the wing section410to pivot about the hinge418. The torque transfer linkage420may be configured such that it does not resist movement of the wing section410any more than necessary (i.e., any more than friction between parts), which may be accomplished by orienting the respective single degrees of rotational freedom of the first pivot connection, the second pivot connection and the third pivot connection in parallel with the hinge pivot axis506. If desired, shock absorbers, springs, travel stops, or other suspension features may be added to the torque transfer linkage420.

The relative elevations of the pivot connections512,514,516can vary (e.g., the second pivot connection514may be above or below one or both of the other pivot connections), and the linkage is not required to be symmetrical. The orientation of the links508,510could be downward, such as shown, or upward if such configuration is found to be more advantageous to the overall header design.

The orientation of the pivot connections512,514,516makes the torque transfer linkage420resist torsional loads exerted between the wing section410and the center section402because they do not allow relative rotation in the direction of the torsion force. This improves the torsional resistance of the frame in several ways. First, the linkage inhibits the wing section upper frame412from moving forward relative to the center section upper frame404(i.e., forward translation in a horizontal plane). Second, the linkage inhibits the wing section upper frame412from rotating relative to the wing section upper frame404in plan view (i.e., about a vertical rotation axis). Third, the linkage inhibits the wing section upper frame412from rotating relative to the wing section upper frame404in side elevation view (i.e., about a horizontal rotation axis extending in the lateral direction).

The effectiveness of the torque transfer linkage420depends on various factors, including the geometry of the parts. Referring toFIG. 7, an exemplary torque transfer linkage420is schematically illustrated in top plan view. Here, the first link508is formed as a first clevis700(i.e., two spaced arms that receive a pin connector) at the first pivot connection512, and a second clevis702at the second pivot connection514. The second link510is formed as a clevis704at the third pivot connection. However, the second link510is formed as a single body at the second pivot connection514(this is in contrast withFIGS. 4-6, which show the second link510being formed with a clevis at the second pivot connection514, which is another optional shape). The center section upper frame404and wing section upper frame412are also shown as single bodies, but these may be formed as clevises as well. In this embodiment, the first pivot connection512, second pivot connection514and third pivot connection516are all formed as double-shear pivot connections. That is, the load acting across the pin portion of each pivot connection generates shear loads at two locations (i.e., at each location where the pin joins the two adjacent components).

To this end, the links508,510may be constructed with particular geometries that are expected to provide improved torque transferring capability. For example, each link508may be described as having an operative length L and an operative width W. The operative length is the distance between the attached pivot connections as measured at the respective rotation axes of the pivot connections. Thus, the operative length L of the first link508is the distance between the first pivot connection512and the second pivot connection514, and the operative length L of the second link510is the distance between the second pivot connection514and the third pivot connection516. In each case, the location of the pivot connection512,514,516is measured at its rotation axis. The operative width W is measured as the distance between the most distant force-reacting surfaces at the respective pivot connection. For example, at the first pivot connection512, the operative width W is measured at the outer faces of the clevis, assuming that the clevis bearing surfaces (e.g., bushings or bearing) terminate at the outer faces. If the clevis has bearing surfaces that stop short of the outer faces, then the operative width W would be less (i.e., to the outer faces of the bearing surfaces) due to the fact that the bearings surfaces provide the force-reacting capability of the connection. The operatives widths W of the links508,510at the second pivot connection514and third pivot connection516would be measured the same way. For example, the operative width of the second link510at the second pivot connection514would be the distance W′ between the outer faces of the single body formed at that end.

The particular geometry of the operative length and operative width can optimized using conventional testing methods, such as finite element modeling or empirical testing. Factors that might be considered when developing the geometry may include (but do not require) the amount of rotation required by the lower frame hinge without locking up, and the desired motion resistance between the upper frame members. In general, it is expected that increasing the operative width in plan view will improve bending resistance in the fore-aft direction and making the links both wider and taller will improve shear resistance in the fore-aft direction, and increasing the polar moment of the links will improve torsion resistance.

While the foregoing configuration is expected to decrease droop at the ends of the wing sections410, other embodiments may use different types of torque-transferring linkage. For example, the double-shear connections may be enhanced by adding additional shear paths, such as by forming them with additional plates in the form of a piano hinge or the like. For purposes of this disclosure, a double-shear connection includes connections that have additional connections (e.g., a quadruple-shear connection). As another example, shown inFIG. 8, the link800may be relatively narrow along the axis of the pivot connection802, but the link800and the adjacent upper frame804or link may be shaped with large surfaces that abut one another in a plane perpendicular to the pivot connection axis, to thereby define a relatively large surface for transferring torque. It will also be understood that it is not strictly necessary for all or even any of the pivot connections to be a double-shear connection. A sufficiently robust single-shear connection can effectively transfer torque, particularly if the pin is relatively large in diameter and long along the rotation axis. Thus, single-shear pivot connections may be substituted for the foregoing double-shear pivot connections. Other alternatives and variations will be apparent to persons of ordinary skill in the art in view of the present disclosure.

The links of the torque transfer linkage420may have any suitable construction. One exemplary construction is shown inFIG. 9. Here, a link900for a torque transfer linkage420has a first link arm902extending from a first pivot connection904to a second pivot connection906, and a second link arm908extending from the first pivot connection904to the second pivot connection906. The link arms902,908may be completely separate, but more preferably they are connected by a link body910. The link body910adds stiffness to the link900, and can help increase the overall torque transferring capability of the torque transfer linkage420. The link arms902,908and link body910may be formed from welded plates and/or folded sheet metal, a bolted-together assembly of parts, partially or completely from cast metal, and so on. Other alternatives and variations will be apparent to persons of ordinary skill in the art in view of the present disclosure.

It has been found that adding a torque transfer linkage to a wing section of a multi-segment header provides significantly less wing section droop. For example, the deflection of the wing sections at their lateral ends can be reduced by over 10% as compared to an identical header lacking the torque transfer linkage. Furthermore, the torque transfer linkage helps mitigate the appearance of a distinct drop in the cutter bar assembly at the location where the center section transitions to the wing sections.

The present disclosure describes a number of inventive features and/or combinations of features that may be used alone or in combination with each other or in combination with other technologies. The embodiments described herein are all exemplary, and are not intended to limit the scope of the claims. It will also be appreciated that the inventions described herein can be modified and adapted in various ways, and all such modifications and adaptations are intended to be included in the scope of this disclosure and the appended claims.