Abstract:
An agricultural harvester includes a base unit and a header coupled with the base unit. The header includes a frame; at least one draper belt; a header lift detector providing an output signal indicating a lift state of the header; and a draper belt accelerator receiving the output signal from the header lift detector and accelerating each of the draper belts upon receipt of the output signal.

Description:
FIELD OF THE INVENTION 
     The present invention relates to agricultural harvesters, and, more particularly, to agricultural harvesters including a draper cutting platform. 
     BACKGROUND OF THE INVENTION 
     An agricultural harvester, such as a windrower or combine, is a large machine used to harvest a variety of crops from a field. In the case of a combine, during a harvesting operation, a header at the front of the combine cuts ripened crop from the field. In the case of thinner stemmed crops such as soybeans, wheat, etc. which may be cut with a sickle bar carrying a plurality of knives, the header may also be known as a cutting platform. A feederhouse supporting the header transfers the crop material into the combine. Threshing and separating assemblies within the combine remove grain from the crop material and transfer the clean grain to a grain tank for temporary holding. Crop material other than grain exits from the rear of the combine. An unloading auger transfers the clean grain from the grain tank to a truck or grain cart for transport, or to another receiving bin for holding. 
     In the case of a windrower, during a harvesting operation, a header at the front of the windrower cuts ripened crop from the field. The crop is transported to the rear of the header and forming shields form a windrow of the crop between the tires of the vehicle for natural dry down of the crop. A subsequent field operation picks up the windrows for further processing, such as separating and cleaning in the case of grain crops, or baling or chopping in the case of hay. 
     A cutting platform may generally be of two types. One type typically has a sheet metal floor with a dual feed auger near the rear of the cutting platform for feeding the crop material longitudinally to the feeder housing. A cutting platform of this type with auger feed is more common. 
     Another type of cutting platform, also known as a draper platform, utilizes a flat, wide belt, referred to as a draper or draper belt to convey crop material. The arrangement and number of belts vary among platforms. One style of draper platform used on a combine has two side belts that convey crop material longitudinally, to the center of the platform, where a center feed belt moves the crop material laterally into the feeder housing. Each belt is wrapped around a pair of rollers, one being a drive roller and the other being an idler roller. An example of this type draper arrangement is disclosed in U.S. Pat. No. 6,202,397, which is assigned to the assignee of the present invention. 
     An advantage of a draper platform is that larger amounts of crop material can be transported without plugging, etc. For example, with wide platforms approaching 40 feet or even larger, the amount of crop material transported to the feeder housing can be substantial. With an auger feed platform, the crop material may bind between the auger and the back wall of the platform. In contrast, with a draper platform, the crop material is carried on top of the belt with less chance for plugging. 
     With wider draper platforms from 25′ to 40′ as described above, controls are provided to allow an operator to finely tune the speeds of the draper belts, reel and cutter bar based on the particular crop and operating conditions. 
     Typically when windrowing a field the operator will use one of two methods. One method is to make a few passes around the field and then cut back and forth laying the windrows parallel to each other. The second method is to cut around the field in one direction working from the outside in. Generally the corners are made square by cutting out, picking up the header (avoiding dragging it through a crossing windrow), turning around and lowering the header before entering crop. 
     When a row is completed and the head pulls out of crop it takes a moment for the belts to unload the crop into the windrow. The operator generally raises the head and reduces ground speed to insure the windrows don&#39;t overlap. If the operator does not pause and let the draper belts unload before crossing another windrow, the windrows overlap and are very difficult to pick up with a combine. 
     What is needed in the art is a draper cutting platform that can be operated in an end-of-row condition such that the crop does not cross windrows. 
     SUMMARY OF THE INVENTION 
     The invention in one form is directed to an agricultural harvester, including a base unit and a header coupled with the base unit. The header includes a frame; at least one draper belt; a header lift detector providing an output signal indicating a lift state of the header; and a draper belt accelerator receiving the output signal from the header lift detector and accelerating each of the draper belts upon receipt of the output signal. 
     The invention in another form is directed to a method of operating a cutting platform for use with an agricultural harvester. The method includes the steps of: operating at least one draper belt at a selected first operating speed during normal harvesting; detecting a lift state of the cutting platform; and operating the at least one draper belt at a second operating speed upon detection of the lift state. The second operating speed is greater than the first operating speed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an embodiment of a windrower of the present invention; and 
         FIG. 2  is a top view of the draper cutting platform shown on the windrower of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, and more particularly to  FIGS. 1 and 2 , conjunctively, there is shown a work machine in the form of a windrower  10  of the present invention. Windrower  10  generally includes a traction unit  12  carrying a draper cutting platform  14 . Draper cutting platform  14  may also alternatively be referred to as a “header” herein. 
     Traction unit  12  includes a frame  16  carrying typical components such as an operator cab  18 , engine compartment  20  housing an internal combustion (IC) engine (not shown), a pair of drive wheels  22 , and a pair of rear caster wheel assemblies  24 . Drive wheels  22  are typically at the front of traction unit  12  and caster wheel assemblies  24  are typically at the rear of traction unit  12 . Drive wheels  22  are connected via respective drive motors with a dual path hydrostatic transmission (not shown). It is also possible to drive the drive wheels  22  with a different type of adjustable transmission, such as a hydromechanical or electromechanical transmission. 
     Each caster wheel assembly  24  includes a wheel arm  26  and a caster wheel  28 . Wheel arm  26  is pivotably coupled at the upper end with machine frame  16 , in particular, at the outboard end of a rear axle  30  forming part of machine frame  16 . Wheel arm  26  is shown as a single arm which curves around to the side of wheel  28 , but can also be configured as a fork with distal ends on opposite sides of wheel  28 . 
     An electrical processing circuit  32 , typically mounted within operator cab  18  to the right or rear of the operator, is configured as one or more controllers. In the embodiment shown, controller  32  may include multiple controllers (not shown). For example, controller  32  may include an engine control unit (ECU) which electronically controls operation of the IC engine within engine compartment  20 , and is coupled with a plurality of sensors associated with operation of the IC engine. Further, the ECU may receive output signals from a vehicle control unit (VCU) representing vehicle control parameters input by an operator, such as a commanded ground speed (indicated by a position of the throttle and/or hydrostatic pedal) or a commanded direction of windrower  10  (indicated by an output signal from a steering sensor representing an angular orientation of the steering wheel, or position of joystick(s)). Further, controller  32  may include a transmission control unit (TCU) which electronically controls operation of the transmission, and is coupled with a plurality of sensors associated with operation of the transmission. The ECU, VCU and TCU may be physically separate from each other and coupled together via a bus structure providing two-way data flow, such as a controller area network (CAN) bus. Such controller schemes are known and thus not specifically shown in the drawings or described in detail herein. 
     A header lift detector in the form of an operator input device, particularly in the form of a depressible switch  34 , is coupled with controller  32 . Switch  34  is depressed by the operator to lift draper cutting platform  14  and provides an output signal to controller  32 . Alternatively, the operator input device could be a touch screen, etc. 
     Moreover, rather than using an operator actuated switch to place draper cutting platform  14  in a lift state, it is also possible to use other types of header lift detectors. For example, the header lift detector can be in the form of a position sensor associated with the lift cylinder(s) for lifting the draper cutting platform  14  relative to traction unit  12 . The position sensor can provide an output signal to controller  32  when the cutting platform is at a predetermined height indicating that the cutting platform  14  is in a lift state. Alternatively, the header lift detector can be in the form of a global positioning system (GPS) which senses when windrower  10  is at an end-of-row condition and sends an output signal to controller  32 . 
     Draper cutting platform  14  is typically detachably mounted at the front end of traction unit  12  below operator cab  18  using a lift assembly in the form of a pair of lift arms (not shown). Draper cutting platform  14  generally includes a frame  36 , a pair of transverse side draper belts  38 , a cutterbar assembly  40 , a reel  42  and a pair of reel lift arms  44 . 
     Draper cutting platform  14  is shown as a rigid draper platform in the illustrated embodiment, but could also be configured as a flexible draper. Further, draper cutting platform  14  is shown as not including a center fore-and-aft draper belt between side draper belts  38 , but could be configured with a permanent or removable center draper belt. When the center draper belt is in the installed position, draper cutting platform  14  may be used as a harvester, and when in an uninstalled position, draper cutting platform  14  may be used as a swather or windrower. Additionally, draper cutting platform  14  is shown for use with windrower  10 , but could be configured for use with other applications, such as for use with a traction unit in the form of a combine. Other configurations are also possible and within the scope of this invention. 
     Reel lift arms  44  are pivotally coupled at one end thereof with opposite outboard ends of frame  36 . Reel lift arms  44  also rotationally carry reel  42  at opposite ends thereof. Each reel lift arm  44  may be selectively moved up and down through controller  32  using a hydraulic cylinder, and the pair of hydraulic cylinders are typically coupled in parallel so that they move together upon actuation. 
     Cutterbar assembly  40  is a sickle bar cutter in the illustrated embodiment. Cutterbar assembly  40  is driven by a suitable mechanical drive at one end of draper cutting platform  14 . Alternatively, cutterbar assembly  40  may be a split cutterbar with a common drive or separate drives for each cutterbar. 
     Draper belts  38  travel in a transversely inward direction as indicated by arrows  46 , and deposit the cut crop material into an open area  48  between the draper belts  38 , forming a windrow of the cut crop material. Each draper belt  38  is separately driven by a respective drive motor  50  which is coupled with a respective end roller (not shown) carrying a corresponding draper belt  38 . In the illustrated embodiment, each drive motor  50  is assumed to be a hydraulic motor under concurrent control of controller  32 . The drive motors  50  could also be independently controlled, or could be in the form of electric motors which are under control of controller  32 . 
     According to an aspect of the present invention, draper belts  38  are controllably operated to accelerate to a higher operating speed when draper cutting platform  14  is in a lift state. The “lift state” could correspond to an operator actuated switch, a lift height of draper cutting platform  14 , or an absolute position of windrower  10  within a field. For example, as indicated above, an operator can depress a switch  34  when the cutting platform  14  is at the end of a row. Alternatively, a position sensor can detect the raised position of draper cutting platform  14  when the cutting platform is manually raised at an end of a row. As another example, a GPS can provide a signal that the windrower has moved into the end rows of a field, assuming that the cutting platform has been manually or automatically raised at the edge of the end rows. 
     Upon detection of a “lift state” of draper cutting platform  14 , controller  32  controls drive motors  50  to accelerate side draper belts  38  to a higher operating speed and discharge the cut crop material into open area  48  before windrower  10  crosses over the other end rows at the end of the field. Drive motors  38  and controller  32  together act as a draper belt accelerator to accelerate draper belts  38  to a speed which is higher than a normal operating speed. Draper belts  38  are preferably simultaneously controlled using controller  32 , but could also be separately and independently controlled. The draper belts can then continue to operate at the higher speed for a predetermined period of time, or until the draper cutting platform  14  is returned to at or near an operating height when an operator again depresses switch  34 , or the lift cylinder sensor detects the cutting platform at or near an operating height. 
     In the embodiment illustrated in  FIGS. 1 and 2 , the draper belts  38  are accelerated on a windrower. However, it is also possible that this same inventive concept can be used on other types of work machines with draper belts. For example, it may be possible to operate a combine with a draper cutting platform such that the draper belts are accelerated to a higher operating speed depending on the lift state of the cutting platform and/or position of the combine with a field. It will be appreciated that if the operating speed of the draper belts is increased on a combine, it may be desirable to increase other component operating speeds, such as the cylinder speed, etc. 
     Moreover, in the embodiment illustrated in  FIGS. 1 and 2 , the draper belts are accelerated upon occurrence of a header state in the form of a header lift state, detected or assumed in various ways as described above. However, it is possible that the draper belts can be accelerated upon an operator input or detection of some other state other than a lift state associated with draper cutting platform  14 . For example, it may be possible that the header state could correspond to an automatic detection of crop load on the draper cutting platform  14 , such as may occur under certain slugging conditions, etc. 
     Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.