Patent Description:
The width of the combine header determines how much crop is collected during each pass of the combine through a field. In some cases, it is desirable to increase the width of the header to improve harvesting efficiency in terms of the number of passes required to completely harvest a given area. However, wider headers can be less effective at following the ground contours than a narrow header, and this can lead to less efficient harvesting of low-growing crops or crops planted on particularly uneven terrain.

To address the problem of undulating terrain, headers have been made with articulated sections. For example, <CIT> discloses a combine draper head having a center section and a pivotable "wing" located on each side of the center section. As another example, <CIT> discloses a combine having an articulated header that can be moved to different positions to improve harvesting and also provide a more compact profile during transport. <CIT> and <CIT> also show combines having headers with pivoting elements.

A potential problem with articulated headers is the possibility that the wings will contact the ground. To prevent such contact, the wings might be supported on caster wheels or the like that extend between each wing and the ground. In other cases, the wings might be supported by a control mechanism, such as one or more single-acting or double-acting hydraulic pistons, to actively control the position of the wing. For example, <CIT> shows an articulated header having wings that are each connected to the center section by a respective pivot and a respective hydraulic piston. Operation of the piston causes the wing to rotate about the pivot to change its angular position relative to the center section and its orientation relative to the ground.

<CIT> describes a multi-section header with flexible crop cutting knife. <CIT> describes a crop machine with an electronically controlled hydraulic cylinder flotation system.

The inventor has determined that articulated headers are subject to potential failure modes that are not adequately addressed by the known 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.

In one exemplary embodiment, there is provided a header for an agricultural vehicle. The header includes all the features of claim <NUM>.

In another exemplary embodiment, there is provided an agricultural combine having a chassis and a header assembly attached to the chassis. The header assembly comprises a header according to claim <NUM>.

The load sensor may be operatively connected to the actuator, and may be, for example, a pressure sensor or load sensor.

The header wing section may be a draper deck having a frame operatively connected to the base structure, one or more draper arms connected to the frame, and a conveyor supported on the one or more draper arms and configured to move crop material towards the base structure. The load sensor may be operatively connected to the draper arms.

In another embodiment, there is provided a method for controlling a header assembly for an agricultural vehicle having a base structure and a header wing section attached to the base structure by an articulated joint. The method includes determining a magnitude of a gravitational load on the header wing section, comparing the magnitude of the gravitational load to a predetermined load value, and sending a control signal to prevent the header wing section from being moved towards a raised position upon determining that the magnitude of the gravitational load is greater than the predetermined load value.

Embodiments of inventions will now be described, strictly by way of example, with reference to the accompanying drawings, in which:.

The drawing figures depict one or more implementations in accordance with the present concepts, by way of example only, not by way of limitations.

Referring now to the drawings, and more particularly to <FIG>, there is shown an exemplary embodiment of an agricultural vehicle <NUM> in the form of a combine harvester which generally includes a chassis <NUM> and a header <NUM> carried by the chassis <NUM>. The chassis <NUM> is supported on driving wheels <NUM> or tracks, as known in the art, and configured to move in a forward direction, illustrated as arrow F, during harvesting operations. For simplicity, only the front portion of the vehicle <NUM> is shown in the top view of <FIG>.

The header <NUM> is connected to the chassis <NUM> by a mount <NUM>. The mount <NUM> may comprise a feeder house or grain conveyor configured to collect crop material and direct it to the inner workings of the vehicle <NUM>. Such inner workings typically will also include additional systems for the separation and handling of collected crop material, such as threshers, separators, grain elevators, a grain tank, a straw chopper and spreader, and so on. Such additional systems are known in the art and omitted from view for brevity of description. It should also be appreciated that the header <NUM> described and illustrated herein does not necessarily need to be included on a combine harvester, but can be incorporated in other agricultural vehicles such as mowers. The mount <NUM> may be a simple rigid connection or an articulated connection comprising one or more linkage arms and actuators (e.g., hydraulic pistons), as known in the art.

The header <NUM> includes a center section <NUM> and two wing sections <NUM>. The wing sections <NUM> each may be connected at a proximal end thereof to the center section <NUM>. The center section <NUM> and wing sections <NUM> may include any suitable operating mechanisms, such as mowers, seeders, tilling mechanism, and so on. In the shown embodiment, however, the center section <NUM> and wing sections <NUM> comprise a so-called draper head, in which each section <NUM>, <NUM> includes a respective conveyor system <NUM>, cutting system <NUM> and reel <NUM> (the reel <NUM> is partially omitted to show underlying parts more clearly). The conveyor systems <NUM> on the wing sections <NUM> are configured to move crop material towards the center section <NUM> (and the mount <NUM>). The center section <NUM> has two conveyor systems <NUM> that move crop material received from the wing section <NUM> towards the mount <NUM>. At the middle of the center section <NUM>, there is a feeder conveyor <NUM> that collects the crop material from the conveyor systems <NUM> and directs it into the vehicle <NUM> for further processing. The conveyor systems <NUM> may comprise conveyor belts, augers, or the like. The cutting system <NUM> is provided to cut crop material from the ground, and the reel <NUM> to help hold, lift and move the crop material towards the conveyor systems <NUM>. The general details and features of the conveyor systems <NUM>, cutting systems <NUM> and reels <NUM> will be understood by persons of ordinary skill in the art, and need not be described herein in detail.

The wing sections <NUM> are movably connected to the center section <NUM> by respective articulated joints <NUM>. The articulated joints <NUM> allow the wing sections <NUM> to move, relative to the center section <NUM>, between a lowered position and a raised position. The lowered position refers to the position of the wing section <NUM> when it is relatively close to the ground, and the raised position refers to the position of the wing section <NUM> when it is relatively far from the ground. For example, <FIG> shows a front view of the vehicle <NUM> and header <NUM> with the one wing section <NUM> on the left in a lowered position, and the other wing section <NUM> in a raised position. The precise range of travel may depend on operating requirements or other factors, but it is preferred that the wing sections <NUM> be movable upwards and downwards relative to a normal operating position that would be used on level ground. For example, a pivoting wing section <NUM> might be movable between a downward angle (e.g., <NUM> degrees downward as measured relative to a plane perpendicular to the gravitational direction) at the lowermost lowered position, and an upward angle (e.g., <NUM> degrees upwards as measured relative to a plane perpendicular to the gravitational direction) at the highest raised position. The range of motion for wing sections <NUM> that slide or translate without a corresponding pivoting motion may be specified as linear travel in the downward and upward direction (e.g., <NUM> inches downward from the normal position in the gravitational direction, and <NUM> inches upwards from the normal position in the gravitational direction).

Any type of articulated joints <NUM> may be used to provide relative movement between the wing sections <NUM> and the center section <NUM>. For example, the articulated joints <NUM> may comprise pivot connectors <NUM> that are oriented with one or more pivot axes extending parallel to the forward direction F (see, e.g., <CIT>). The articulated joints <NUM> also may allow pivoting movement relative to the center section <NUM> about multiple axes of rotation (see, e.g., <CIT>). The articulated joints <NUM> also may comprise linkages to allow relative translational movement without corresponding relative angular movement, or angular movement about a virtual pivot axis (see, e.g., <CIT> and <CIT>). The articulated joints <NUM> also include respective control mechanisms, such as an actuator <NUM>, to control the position of the wing section <NUM> relative to the center section <NUM> and mount <NUM>, such as discussed in more detail below.

The actuators <NUM> may comprise any suitable movable linkage mechanism for moving the wing sections <NUM>. In <FIG>, the actuators <NUM> are shown as pressurized actuators, such as pneumatic or hydraulic piston and cylinder assemblies that are operated by valves and a source of pressurized fluid (gas, oil, etc.). In this case, the piston/cylinder assembly provides a movable linkage in the form of a adjustable-length telescoping connector. The actuators <NUM> alternatively may comprise electric motors, pressure-operated rotational drives, and so on as the power supply, and other kinds of movable linkage to provide the desired controlled movement. For example, an electric motor may be provided to drive a worm gear that engages a corresponding nut to provide an alternative telescoping linkage. The actuator may be bidirectional (able to forcibly move the wing section <NUM> both up and down), or unidirectional (only able to lift the wing section <NUM>, while lowering is achieved by gravity). A unidirectional actuator may, for example, be a motor and spool to selectively retract a cable to provide an upwards-only driving force to lift the wing section <NUM>, or a single-acting hydraulic piston that is pressurized to apply a force to lift the wing section <NUM>, and depressurized to allow gravity to drop the wing section <NUM>. The actuators <NUM> also may include any suitable drive mechanisms to convert a motive force to the desired type of motion, such as gears, drive shafts, worm screws, and so on. These and other such actuators are known in the art, and need not be described in more detail herein.

One preferred embodiment includes a center section <NUM> and two wing sections <NUM>, but other embodiments may include only two wing sections that are connected to the mount <NUM> by respective articulated joints <NUM> or other configurations. In another example, the wing section <NUM> may be mounted directly to the chassis <NUM>. Thus, a mount <NUM>, a center section <NUM>, a chassis <NUM>, or any other structure may provide a base structure to which the wing section <NUM> is attached. An example of an alternative configuration is shown in <FIG>. Here, the mount <NUM> comprises a frame <NUM>, and the articulated joints <NUM> each comprise a pivot connection <NUM> with a rotation axis extending parallel with the forward direction F, and an actuator <NUM> joining the proximal end of each wing section <NUM> to the frame <NUM>. Each wing section <NUM> is configured to pivot about the respective pivot connection <NUM> under the control of the respective actuator <NUM>, which extends and contracts to move the wing section <NUM> between the lowered position (shown on the left), and the raised position (shown on the right). Other embodiments may have any desirable combination of wing sections and center sections, such as a center section and a single wing section, or only a wing section (such as in a highway embankment mower configuration) to provide offset harvesting.

Headers having wing sections <NUM> are subject to loading forces that can potentially damage the header or other parts of the vehicle to which the header is attached. For example, it is possible for the cutting system <NUM> or other operative parts of the wing section <NUM> to strike the ground when passing over undulating terrain.

One at least partial solution to this problem is to provide ground supports, such as fixed or movable wheel assemblies, at locations along the span of the wing section <NUM>. However, such supports can interfere with harvesting and complicate the structure, and can reduce the ability to conform the orientation of the wing section <NUM> to the ground in some circumstances.

Another partial solution to this problem is to provide feedback sensors to help determine when the wing section <NUM> is getting too close to the ground, and signal the actuator <NUM> to lift the wing section <NUM>. For example, height detecting sensors (pivoting wheels mounted to potentiometers, sonar rangefinders, radar rangefinders, infrared proximity sensors, etc.) can be used to measure distance to the ground. However, such sensors can be confounded by the presence of crop material, and might not provide an accurate measurement when the wing section <NUM> is subject to torsional loads that tilt the sensor forward or backwards along the direction of travel.

Another partial solution is to provide a load sensor that measures a backwards force on the wing section <NUM> (i.e. force opposite to the direction of travel) to determine when the wing section <NUM> is too close to or in contact with the ground, and then signal to lift the wing section <NUM> or slow the vehicle when such events occur. One such device is discussed in <CIT>. However, the use of a load sensor to measure deflection of an elongated body such as a draper header wing section <NUM> can be subject to errors caused, for example, by complex loading on the wing section <NUM> (e.g., combined compression, drag and bending as might occur upon oblique contact with the ground or an obstacle). Furthermore, the inventors have found that controlling the wing section <NUM> to raise when it experiences an excessive load can at least momentarily increase loading on the wing section <NUM> to a point where the act of lifting the wing section <NUM> causes more damage than it avoids.

The inventors have found that these shortcomings can be addressed, at least in part, by a wing section control system that detects excess loading on the wing section, and issues an instruction to slow or stop the vehicle without lifting the wing section. It has also believed that direct measurement of wing section deflection can provide more accurate and useful data to assist with controlling the operation of the header.

An exemplary control system <NUM> and related features for a header <NUM> for an agricultural vehicle <NUM> are shown in <FIG>. In this case, the header <NUM> again comprises a center section <NUM> and two wing sections <NUM>. As before, the wing sections <NUM> are connected to the center section <NUM> by respective articulated joints <NUM> having pivot connections <NUM> and controllable actuators <NUM>.

Each actuator <NUM> comprises a pressurized actuator, such as a hydraulic piston and cylinder, which may be a single-acting actuator configured to raise the wing section <NUM> upon application of increased pressure, and drop the wing section <NUM> upon reduction of the pressure in the cylinder. Each actuator <NUM> is operatively connected to a hydraulic controller <NUM> via one or more respective control lines <NUM>. The hydraulic controller includes of pressurized hydraulic fluid (e.g., a pump or pressurized reservoir), valves and other features used to control the displacement of fluid to control the operation of the actuators <NUM>, as known in the art. The control system <NUM> is operatively connected to the hydraulic controller <NUM> and configured to issue commands to drive the hydraulic controller <NUM> to articulate the actuators <NUM> as desired.

Each wing section <NUM> also includes a load sensor <NUM> to evaluate a gravitational load (i.e., load in the global vertical direction) on the wing section <NUM>. In this case, the load sensors <NUM> comprise pressure sensors that are operatively connected to a respective actuator <NUM>, and configured to detect changes in pressure in the respective actuator <NUM> and/or control line <NUM>. Thus, the load sensors <NUM> are able to detect increases in loading on the wing section <NUM> by measuring pressure increases exceeding the control pressure provided by the hydraulic controller <NUM> (i.e., backpressure). The load sensors <NUM> preferably are configured to predominantly read gravitational load, but it will be appreciated that forces applied to the wing section <NUM> in other directions also may be detected by the load sensors <NUM> without significantly affecting the operation of the system. Other embodiments of load sensors <NUM> are discussed in more detail below. The load sensors <NUM> are operatively connected to the control system <NUM> by low-voltage wiring, wireless communication, or the like.

Each wing section <NUM> also may include a deflection sensor <NUM> configured to provide a measure of how much the wing section <NUM> has moved relative to the center section <NUM>. The deflection sensors <NUM> may provide an indirect indication of deflection by measuring stresses or loading on the various parts of the header <NUM>, as described in <CIT>, but in a more preferred embodiment the deflection sensors <NUM> are configured to directly measure wing section deflection, such as discussed in more detail below. The deflection sensors <NUM> are also operatively connected to the control system <NUM> via low voltage wires, wireless communication or other known electrical connections.

An exemplary operation of the control system <NUM> is illustrated in <FIG>.

In step <NUM>, the control system <NUM> begins an overload check routine.

At step <NUM>, the control system acquires load sensor data by obtaining readings from the one or more load sensors <NUM>. Any type of filtering, amplification, or other pre-processing may be used during data acquisition. The load sensor data also may comprise a single discrete value (e.g., a single pressure sensor reading), or a collection of multiple readings (e.g., a time-stamped sequence of pressure sensor readings, an integrated sum of pressure sensor readings over a fixed sampling time, etc.).

At step <NUM>, the control system <NUM> compares the load sensor data with a predetermined threshold load value to determine whether any of the load sensors <NUM> has exceeded the threshold load value. The threshold load value may be any value selected to represent an operation limit for the header, a value representative of a ground strike, or any other value. The threshold value also may be altered by an operator to account for different operating conditions (e.g., a lower threshold when harvesting lighter crop) or based on other considerations (e.g., calibrating or fine-tuning). The determination in step <NUM> may comprise a simple numerical comparison comparing an instantaneous sensor reading with a threshold value, or it may involve substeps such as filtering input data values, integrating input data values over time, averaging a set of values, evaluating data trends, and so on. The threshold value itself may be a simple number representing an output data value (e.g. a pressure value, if a pressure sensor is used), or a number or equation representing a mathematical manipulation of the output data (e.g., a value of slope of a curve to indicate a sudden change in value; a Fourier transformation to indicate fluctuations at particular vibration frequencies; etc.). Other alternatives and variations will be apparent to persons of ordinary skill in the art in view of the present disclosure.

If the control system <NUM> determines that the load sensor data does not exceed the threshold load value, the process continues to step <NUM>. In step <NUM>, the control system acquires deflection sensor data from the one or more deflection sensors <NUM>. As with the load sensor data, the deflection sensor data may be pre-processed, and may include single data points or collections of multiple data points collected over time.

Next, in step <NUM>, the control system <NUM> compares the deflection sensor data with a predetermined threshold deflection value to determine whether the threshold deflection value has been exceeded. As with step <NUM>, this process may compare single values, integrated values, slope data, frequency domain data, and so on.

If the threshold deflection value has not been exceeded, then the process returns to begin again to provide constant or near-constant monitoring for overload conditions.

If the control system <NUM> determines that one or both of the threshold load value and the threshold deflection value is exceeded, it proceeds to take corrective measures. For example, if the threshold load value is determined to have been exceeded, the control system <NUM> may proceed to process step <NUM>, in which the control system <NUM> issues a control signal to suppress actuator control. This control signal prevents or limits the ability of the operator or an automated control system to operate the actuator <NUM> to raise the wing section <NUM> that has experienced the overload condition. For example, this control signal can prevent any elevation of the wing section <NUM>, prevent elevation of the wing section <NUM> at a rate greater than a predetermined elevation rate, or lower the wing section <NUM>. As indicated above, this action is expected to help prevent excessive damage that might occur when an operator or automated system attempts to raise an overloaded wing section <NUM>.

Upon detecting a load sensor overload condition, the control system <NUM> also may perform a vehicle stop routine <NUM>. In this step, the control system <NUM> issues a control signal to cause the vehicle <NUM> to slow down and stop at a predetermined rate. Such commands may be provided to the vehicle wheel drive system or brakes, and may comprise any suitable action (e.g., reduce throttle opening; terminate spark ignition; activate brakes, etc.). The vehicle stop routine <NUM> also may include steering control commands to cause the vehicle <NUM> to turn towards the affected wing section <NUM>, such that less of the vehicle motion is transferred to the distal end of the affected wing section <NUM>. For example, the vehicle stop routine <NUM> can issue a steering command to turn the steered wheels to an angle at which the vehicle's turn center is located at or near the distal end of the affected wing section. Such angle may be readily determined by evaluating the geometric configuration of the vehicle <NUM> and header <NUM>.

The control system <NUM> also may issue the same or similar corrective commands upon detecting a deflection overload condition in step <NUM>. For example, upon registering a deflection overload in step <NUM>, the control system <NUM> may proceed to step <NUM> and <NUM>. Alternatively, as shown by example in <FIG>, the control system <NUM> may take a different approach to addressing a deflection overload, such as by proceeding directly to a vehicle stop routine <NUM> without suppressing elevation of the wing section. In another embodiment, if a deflection overload is detected in step <NUM> without also detecting a gravitational load overload in step <NUM>, the control system <NUM> may issue a command to raise the affected wing section <NUM> and may not begin the vehicle stop routine <NUM> at all.

Other corrective actions that might be taken include, but are not limited to: illuminating a warning light in the vehicle cabin, activating an audible warning signal, terminating operation of draper conveyor motors, terminating operation of reels, terminating operation of a cutting system, or terminating other vehicle or header operations. The control system <NUM> also may maintain a continuous record of load and deflection readings, or may store overload readings into an error file. The control system <NUM> further may be configured to send error or incident reports to a remote computing center via wireless communication (cellular or the like), to maintain an operation record of the header and vehicle systems.

As shown in the logical flow path in <FIG>, the control system <NUM> may continue to monitor the load sensors <NUM> and deflection sensors <NUM> after corrective steps have been taken. If and when the sensors stop indicating overload conditions, the control system <NUM> may return the vehicle to normal operation. However, the control system <NUM> may require the operator to perform actions to verify that no potentially-harmful conditions remain before allowing the vehicle and header to resume normal operation.

It is also envisioned that the control system <NUM> can operate with a tiered reaction structure to take different corrective actions depending on the magnitude of the wing section's detected load state or deflection. For example, the control system <NUM> could suppress actuator control by limiting the rate at which the wing section <NUM> can be elevated if the load sensor indicates a moderately high loading, and prevent any elevation of the wing section <NUM> if the load sensor indicates a very high loading. Other alternatives and variations will be apparent to persons of ordinary skill in the art in view of the present disclosure.

The shown arrangement of steps is not strictly required. In use, the control system <NUM> may periodically or essentially continuously (i.e., at a maximum clock cycle of the controller system's processor) monitor the output of one or both of the load sensors <NUM> and the deflection sensors <NUM>. The control system <NUM> also may operate completely separate processes to detect load and deflection data, or may not detect both load and deflection data (e.g., only detecting load data). The control system <NUM> further may perform alternative corrective actions or perform the actions in a different order. The control system <NUM> also may comprise a hierarchical control system that uses an arbitrator to control operations of the header and vehicle based on output of a variety of sensors. For example, the control system <NUM> may allow a driving routine (i.e., allowing the operator to control vehicle speed) to continue unless an overload signal is received from the load sensors <NUM>, at which time the control system arbitrator will cause the control system to enter a drive shut down mode. Such control algorithms and schemes can be implemented in virtually any variety without departing from the basic processes of querying sensors and making control adjustments as described herein, and the invention is not intended to be limited to any particular control scheme.

The control system <NUM> may be implemented using any suitable arrangement of processors and logical circuits. <FIG> is a block diagram of exemplary hardware and computing equipment that may be used as a control system <NUM> as discussed herein. The control system <NUM> includes a central processing unit (CPU) <NUM>, which is responsible for performing calculations and logic operations required to execute one or more computer programs or operations. The CPU <NUM> is connected via a data transmission bus <NUM>, to sensors <NUM> (e.g., load sensors <NUM> and deflection sensors <NUM>), an input interface <NUM>, an output interface <NUM>, and a memory <NUM>. The input and output interfaces <NUM>, <NUM> may comprise any suitable user-operable and perceivable system, such as a touchscreen controller/display, control knobs or joysticks, and the like. One or more analog to digital conversion circuits may be provided to convert analog data from the sensors <NUM> to an appropriate digital signal for processing by the CPU <NUM>, as known in the art. The CPU <NUM> also may be operatively connected to one or more communication ports <NUM>, such as serial communication ports, wireless communication ports, or the like.

The CPU <NUM>, data transmission bus <NUM> and memory <NUM> may comprise any suitable computing device, such as an INTEL ATOM E3826 <NUM> Dual Core CPU or the like, being coupled to DDR3L <NUM>/<NUM> SO-DIMM Socket SDRAM having a 4GB memory capacity or other memory (e.g., compact disk, digital disk, solid state drive, flash memory, memory card, USB drive, optical disc storage, etc.). The selection of an appropriate processing system and memory is a matter of routine practice and need not be discussed in greater detail herein.

It will be appreciated that the manner in which the gravitational load and deflection of the wing sections <NUM> are determined may be different for different embodiments. For example, alternative embodiments of load sensing systems are shown in <FIG> and <FIG>.

<FIG> illustrates an exemplary wing section <NUM> provided in the form of a draper head. The wing section <NUM> is shown with external covers and some other features omitted for the sake of simplifying explanation of the relevant parts. The wing section <NUM> extends from a proximal end <NUM>, which is attached to a center section <NUM> or mount <NUM>, to a distal end <NUM>. The main structural body of the wing section <NUM> is formed by a frame having an upper frame member <NUM> and a lower frame member <NUM>, which are connected to one another by struts <NUM>. The upper and lower rails <NUM>, <NUM> connect at the proximal end <NUM> to an articulated joint having an actuator, such as described above, and support the remaining parts of the wing section <NUM>.

The frame supports a draper deck assembly. The draper deck assembly includes a plurality of draper arms <NUM> that extend in the forward drive direction from the frame. The draper arms <NUM> may be connected to one another by lateral supports <NUM>. A cutting system <NUM> is attached to the fronts of the draper arms <NUM>. A conveyor, such as a conveyor belt or auger is provided on the draper arms <NUM>, as known in the art, but this feature is not shown in <FIG> and <FIG> for the sake of clarity.

The draper arms <NUM> may be configured to move in the vertical direction relative to the frame, in order to position the cutting system <NUM> at the desired cutting height. For example, as shown in <FIG> and <FIG>, the draper arms <NUM> may have a pivot axle <NUM> that is connected to a corresponding mount on the lower frame member <NUM>. This pivot <NUM> provides an axis of rotation that extends perpendicular to the forward direction and parallel to the ground, and motion about this axis causes the front end <NUM> of the draper arm <NUM> to move up and down. The position of the draper arm <NUM> is controlled by an actuator, which in this case is a pneumatic airbag <NUM>. At one end, the airbag <NUM> is connected to the frame by a mount <NUM>, which is rigidly attached to the strut <NUM> or elsewhere on the frame. The other end of the airbag <NUM> is connected to the draper arm <NUM> at a location offset from the pivot axle <NUM>. The airbag <NUM> is connected by a fitting <NUM> to a source of pressurized gas (not shown). Changing the pressure of the gas causes the airbag <NUM> to expand or contract, which causes the draper arm <NUM> to rotate about pivot axle <NUM> to provide the desired vertical control of the cutting system <NUM>. The range of motion of the draper arm <NUM> may be controlled by a pin <NUM> that is rigidly connected to the frame and fitted into in a corresponding slot <NUM> in the draper arm <NUM>.

In this embodiment, the gravitational load on the wing section <NUM> can be determined by evaluating the pressure of the gas in the pneumatic airbags <NUM>. This load detection is similar to the load detection described above in relation to using pressure in the actuator <NUM> hydraulic line. For example, a pressure sensor may be provided in the airbag <NUM> or its pneumatic supply line, and monitored to detect pressures above an expected value for normal operation.

This embodiment is expected to have certain advantages over measuring load via pressure changes in a wing section lifting actuator <NUM>. For example, if multiple pressure sensors are used at different airbags <NUM>, fluctuations in gravitational load may be detected at multiple locations along the length of the wing section <NUM> to provide a more accurate assessment of potentially hazardous conditions. In this configuration, a control system <NUM> can evaluate whether there is a large load on only a few draper arms <NUM>, which might indicate a sudden influx of dirt and crop material when the wing section <NUM> strikes a localized high spot on the ground. The control system <NUM> can also differentiate between a dangerous excessive loading near the distal end <NUM> of the wing section <NUM> and a potentially less problematic application of the same magnitude of loading at the proximal end <NUM> of the wing section <NUM>.

Detecting the load on the draper arms <NUM> also helps isolate the load measurement from loads that might be applied directly to the frame. This can be particularly helpful if the wing section <NUM> is constructed such that the draper arms <NUM>, cutting system <NUM> or conveyor/auger are relatively sensitive to high loading but the frame itself is not likely to be damaged by a high load. This arrangement can also reduce the amount of non-gravitational loading that might be detected by the load sensors.

This embodiment also allows the control system to separately control the draper arm <NUM> actuators during an overload condition. For example, the control system can monitor the output of the load sensors, and issue a command to suppress raising the draper arms <NUM> from a lowered arm position to a raised arm position upon determining that the draper arms <NUM> are experiencing an excessive load. Such a command may be issued in parallel with the suppression step <NUM> discussed above in relation to <FIG>, or as part of a separate control algorithm.

It will be appreciated that, in other embodiments, the airbags <NUM> and particular structure of the draper arms <NUM> may be modified or replaced. For example, the draper arms <NUM> may be replaced by panels, or the airbags <NUM> may be replaced by electric or hydraulic motors, or other pressurized actuators such as hydraulic piston and cylinder assemblies. The draper arms <NUM> also may be interconnected and operated by a single actuator. It will also be appreciated that the draper arms <NUM> may be connected to the frame by different connections, such as a flexible leaf spring, a multiple-bar linkage, or the like. Other alternatives and variations will be apparent to persons of ordinary skill in the art in view of the present disclosure.

While the example of <FIG> and <FIG> uses adjustable draper arms <NUM>, other embodiments may use fixed draper arms <NUM>. For example, the airbag <NUM> shown in <FIG> may be a sealed container forming a pneumatic spring, and pressure within the container can be measured to determine gravitational load. As another example, the draper arms <NUM> may be rigidly connected to the frame, and load may be detected by strain gauges <NUM> located on the draper arms <NUM> or frame.

In other cases (whether the draper arms <NUM> are fixed or movable), gravitational load may be determined using load cells between the draper arms <NUM> and the conveyor or auger, strain gauges located on the uprights <NUM> or other parts of the frame, or using other configurations of load cells or the like. As used herein, load cells are any mechanism used to measure physical load on a part, including strain gauges, electrical resistance-based measuring device (e.g., potentiometers), piezoelectric devices, and so on. In still other cases, the gravitational load may be determined by evaluating the operating properties of a motor driving the conveyor. For example, an electric conveyor belt or auger motor may be monitored to evaluate back electromotive force or current draw to evaluate changes in load caused by an influx of material onto the belt or auger, and similar techniques may be used by monitoring pressure required to operate a hydraulic motor at a constant speed. Other alternatives and variations will be apparent to persons of ordinary skill in the art in view of the present disclosure.

Referring now to <FIG>, examples of direct-measurement deflection sensors <NUM> are described in more detail. As noted above, deflection of a wing section <NUM> may be evaluated, with some degree of accuracy, by using strain gauges or load cells to evaluate stresses on the wing section <NUM> or its mounting point to a center section <NUM> or a mount <NUM>. However, such measurements are not necessarily as accurate as measurements provided by direct evaluation of the wing section's position. <FIG> shows two examples of sensor systems that directly measure wing section deflection, and which may provide improved measurement results.

<FIG> is a top view showing a wing section <NUM> mounted to a center section <NUM> by an articulated joint <NUM>. The wing section <NUM> is deflected backwards from the forward travel direction relative to a resting or normal operating position (dashed line). A first example of a deflection sensor is shown in the form of a motion sensor <NUM> located at or near the distal end of the wing section <NUM>. The motion sensor <NUM> may comprise, for example, a solid state electronic <NUM>-axis accelerometer/gyroscope such as the MPU-<NUM> chip-based sensor provided by TDK InvenSense of San Jose, California. The motion sensor <NUM> comprises accelerometers that are capable of detecting linear motion and rotation relative to multiple different axes, and output of the motion sensor <NUM> can be used to evaluate the position of the distal end of the wing section <NUM>. The motion sensor <NUM> may be used in conjunction with a reference motion sensor <NUM> located at the proximal end of the wing section, and/or a reference motion sensor <NUM> located on the center section <NUM> or elsewhere on the vehicle system (e.g., on the chassis <NUM> or mount <NUM>). Using the reference motion sensor <NUM>, <NUM> as a frame of reference, the output of the motion sensor <NUM> at the end of the wing section <NUM> provides a direct measurement of the displacement of the motion sensor <NUM> and the portion of the wing section <NUM> to which it is attached. If desired, additional motion sensors <NUM> may be provided at other locations along the wing section <NUM> to provide more detailed deflection information.

Another example of a deflection sensor is shown as an optical path sensor having an emitter and a detector. The emitter may be a source of focused light, such as a collimated light beam or a laser <NUM>. For example, a laser <NUM> may be located at the proximal end of the wing section <NUM>, and oriented to direct its beam <NUM> onto a sensor <NUM> located at the distal end of the wing section <NUM>. The laser may comprise any suitable light-emitting source, as are well-known in the art. The detector may comprise any photosensitive detector that is capable or determining displacement of the detected light. For example, the detector may be a laser sensor <NUM> comprising a multiple-pixel charged-coupled device (CCD) or complementary metal-oxide semiconductor (CMOS) camera sensor having different sensor locations to track the position of the beam, or the like. The laser sensor <NUM> also may comprise a series of individual light detectors (e.g., photodiodes), that are positioned along a reference surface. The laser sensor <NUM> also may be positioned adjacent the laser <NUM>, and a mirror may be located at the end of the wing section <NUM>. As another example, the laser sensor <NUM> may comprise a simple photodetector, and a retroreflective mirror may be located at the end of the wing section <NUM> and positioned such that the laser beam <NUM> strikes the mirror when the wing section <NUM> is within (or alternatively outside) an acceptable deflection range, to thereby indicate whether the threshold deflection has been reached in a binary sense (i.e., either the reflected beam is detected or it is not). The positions of the emitter and detector can also be reversed, if desired.

A laser <NUM> also may be located on the center section <NUM> (or mount), but in this case provision might have to be made to account for the fact that the wing section <NUM> will be moving up and down relative to the laser <NUM> during normal operation. Such normal operating motion can be addressed by mounting the laser <NUM> on a pivot to follow the motion of the wing section <NUM>, using a laser sensor <NUM> that is insensitive to the vertical position of the laser's beam <NUM> (e.g., a CMOS sensor that extends vertically and in the fore-aft direction), or modulating the laser's beam <NUM> into a vertically-oriented fan shape that projects onto the laser sensor <NUM> throughout the normal range of motion of the wing section <NUM>. Other alternatives and variations will be apparent to persons of ordinary skill in the art in view of the present disclosure.

Although shown collectively in <FIG>, it will be understood that embodiments may use any one, or any combination of such displacement sensors, or other kinds of displacement sensors.

Claim 1:
A header (<NUM>) for an agricultural vehicle (<NUM>), the header (<NUM>) comprising:
a base structure (<NUM>,<NUM>, <NUM>);
a header wing section (<NUM>);
an articulated joint (<NUM>) connecting the header wing section (<NUM>) to the base structure (<NUM>,<NUM>, <NUM>);
an actuator (<NUM>) operatively connected between the header wing section (<NUM>) and the base structure (<NUM>,<NUM>, <NUM>), the actuator (<NUM>) being operative to move the header wing section (<NUM>) relative to the base structure (<NUM>,<NUM>, <NUM>) between a wing lowered position and a wing raised position;
a load sensor (<NUM>) operatively connected to the header wing section (<NUM>); and
a controller (<NUM>) operatively connected to the load sensor (<NUM>) and the actuator (<NUM>), the controller (<NUM>) being configured to acquire load sensor data from the load sensor (<NUM>) to evaluate a magnitude of a gravitational load on the header wing section (<NUM>), characterized in that the controller (<NUM>) is further configured to prevent the actuator (<NUM>) from moving the header wing section (<NUM>) towards the wing raised position if the magnitude of the gravitational load exceeds a predetermined threshold load value.