CA2606003A1 - Header float arm load compensation - Google Patents
Header float arm load compensation Download PDFInfo
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- CA2606003A1 CA2606003A1 CA 2606003 CA2606003A CA2606003A1 CA 2606003 A1 CA2606003 A1 CA 2606003A1 CA 2606003 CA2606003 CA 2606003 CA 2606003 A CA2606003 A CA 2606003A CA 2606003 A1 CA2606003 A1 CA 2606003A1
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- header
- springs
- arms
- load compensation
- compensation system
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- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01D—HARVESTING; MOWING
- A01D41/00—Combines, i.e. harvesters or mowers combined with threshing devices
- A01D41/12—Details of combines
- A01D41/14—Mowing tables
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- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01D—HARVESTING; MOWING
- A01D57/00—Delivering mechanisms for harvesters or mowers
- A01D57/20—Delivering mechanisms for harvesters or mowers with conveyor belts
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- Life Sciences & Earth Sciences (AREA)
- Environmental Sciences (AREA)
- Harvesting Machines For Root Crops (AREA)
Abstract
A float arm load compensation system for a header of an agricultural harvester includes a header frame; a plurality of header float arms pivotally coupled to the header frame; a cutter bar fixed to forward ends of the plurality of header float arms; at least one conveyor belt supported on the plurality of header float arms and configured to traverse the header perpendicular to the direction of travel of the header, wherein the conveyor belt is further configured to receive crop material cut by the cutter bar; and a plurality of springs, wherein each spring is coupled to an associated header float arm of the plurality of header float arms to exert a force on the associated header float arm compensating for the weight of cut crop material supported by the associated header float arm.
Description
HEADER FLOAT ARM LOAD COMPENSATION
Related Aualications This invention claims priority to US Prov. Oat. App. Ser. No. 60/825,857, attorney docket number 17720, entitled "Header Float Arm Load Compensation", which was filed on September 15, 2006 by the same inventors.
Field of the Invention This invention relates generally to harvesters. More particularly, it relates to conveying systems for conveying cut crop material to the harvester vehicle.
Background_of the invention Harvesters have headers (typically called "Draper piatform5") that carry cut crop material on conveyor belts. These conveyor belts extend across the width of the header to a central discharge region of the header. The conveyor belts are supported on rollers that, in tum, are mounted on header float arms that are elongated and extend forwardly. These arms are pivotally mounted to a frame of the header. The forward ends of the header float arms are coupied to and support a cutter bar that extends across the width of the header.
The cutter bar and/or the forward ends of the arms skid across the surface of the ground as the harvester goes through the field harvesting crop. As the harvester is driven through the fieid, the ground rises and falls undemeath the header and the arms pivot up and down responsibly, thereby permitting the cutter bar to follow the contours of the ground more closely.
If the cutter bar and/or the front ends of the arms apply too much pressure to the ground they will dig into the ground and be damaged. Controlling the downforce is therefore important in keeping the header and harvester opera4ng properly.
To reduce the downforce applied by the header to the ground, each arm is partially supported by a hydrauiic, pneumatic, or mechanical spring. The springs are coupled to the frame of the header and transmit some of the crop weight to the frame. They do this by exerting a lifting or "up" force on the arms that counteracts the weight of the arms and the addifional downforce exerted on the arms by the cut crop material that falls backward onto the conveyor belts after it is cut by the cutter bar. The springs transfer some of the weight of the header float arms and cut crop material to the feeder house on which the header is supported and transfer the weight off the cutter bar and ground.
The cut crop material is not evenly distributed across the width of the header conveyors. The crop is cut by the cutter bar across the entire front of the header and then falls backwards onto the conveyor belts, a left conveyor belt and a right conveyor belt. The left conveyor belt carries the cut crop material from the left side of the header to the center section of the header, and the right conveyor belt carries the cut crop material from the right side of the header to the center section of the header. Once the cut crop material reaches the center section of the header, the left and right conveyors dump the cut crop meterial into a center conveyor that carries the cut crop material backwards, through the feeder house, and into the self-propelled vehicle pordon of the harvester.
Depending upon its position across the front of the header, each header float arm needs a different amount of upward counterbalancing force in order that each header float arm exerts the same downforce against the ground that all the other header float arms do. In the ideal situa6on, each header float arm provides the same, optimal downforce against the ground.
In order for each header float arm to provide the same downforce against the ground, each spring must apply a different upforce to Its associated header float arms. This Is necessary since different pordons of the conveyor (and hence each header float arm) support different quantities of cut crop material. As the conveyors move laterally across the width of the header toward the lateral midpoint of the header, more and more cut crop material falls onto the conveyor belt. And the header float arms closer to the lateral midpoint of the header carry a greater and greater weight of cut crop material. This additional crop material resting on the header float arms closer to the lateral midpoint or center of the header means that the header float enns closer to the lateral midpoint require a greater counterbalancing upforce - the force exerted by the springs - if each header float arm is to apply a constant downforce against the ground.
What is needed, therefore, is a control system for applying to each header float arm in the header a counterbalancing upforce that is appropriate to support the crop load and to maintain constant the downforce exerted by each header fioat arm against the ground (either directly, or through the cutter bar). It is an object of this invention to provide such a system.
Summary of the Invention in accordance with the first aspect of the invention of float arm Ioad compensation system for a header of an agricultural harvester is provided, comprising a header frame; a plurality of header float arms pivotally coupled to the header frame; a cutter bar fixed to fonivard ends of the plurality of header float arms; at least one conveyor belt supported on the plurality of header float arms and configured to traverse the header perpendicular to the direction of travel of the header, wherein the conveyor belt is further configured to receive crop material cut by the cutter bar; and a plurality of springs, wherein each spring is coupied to an associated header float arm of the plurality of header float arms to exert a force on the associated header float arm compensating for the weight of cut crop material supported by the associated header float arm.
The springs of the plurality of springs that support float arms closer to the lateral midpoint of the header may be configured to exert a greater upforce on their associated header float arms than other springs of the plurality of springs that support float arms farther from the lateral midpoint of the header. The plurality of springs may be configured to maintain constant the downforce exerted by their associated header float arms against the ground across a width of the header. The load compensation system may further include a control circuit configured to monitor an operational parameter of the agricultural harvester indicative of the load on the at least one conveyor belt. The control circuit may monitor an operational parameter indicative of a load on the rotor of the harvester. The control circuit may be configured to automatically change the forces exerted by the plurality of springs on their associated header float arms in response to changes in the operational parameter. The load compensation system may further include an accumulator containing gas charged hydraulic fluid coupled to the plurality of springs. The load compensation system may further include a valve configured to simultaneously change the force is applied by the plurality of springs by filling and emptying the accumulator. The load compensation system may further include at least first and second accumulators containing hydraulic fluid under pressure, wherein the first accumulator is coupled to a first group of springs of the plurality of springs, and wherein the second accumulator Is coupled to a second group of springs of the plurality of springs. The plurality of springs may be mechanical springs. The mechanical springs may be coil springs.
Brief Desrxigtion f the Drawings FIGURE 1 is a plan view of a harvester having a header in the form of a Draper platform in accordance with the present invention.
FIGURE 2 is a side view of the harvester of FIGURE 1.
FIGURE 3 is a fragmentary cross-sectional view of the header of FIGURES 1-2 taken at section line 2-2 in FIGURE 1.
FIGURE 4 is a schematic diagram of the header of FIGURES 1-3 with alternative springs and a controi circuit for controlling the alternative springs.
FIGURE 5 is a schematic diagram of the header of FIGURE 4 with an aiternati:ve control circuit for controliing the aiternative springs.
Descriotion of the Preferred Embodiments An "upforce", as that term is used herein, refers to a force applied to a header float arm that tends to lift the forward end of the header float arm upward and away from the ground thereby reducing the force of the header float arm against the ground. It does not imply or require that the force itself be directed upward at its point of application to the header float arm. Indeed, depending upon the geometry of the header float arm, the force may be applied to the header float arm in any direction and at any point along the arm, Referring now to FIGURES 1-2, a combine harvester 100 is illustrated, comprising a vehide 102 that is wheeled and self-propelled, and also comprising a header 104 which is a Draper platform that is mounted on the front of the vehicle M.
Vehicle 102 further comprises a feeder house 106 that is pivotally coupled to the front of chassis 108 of vehicle 102. Header 104 is supported on the front of feeder house 106.
Header 104 comprises a frame 112, a plurality of arms 114 (identified collectively as header float arms 114a j), a plurality of springs 116 (identified as springs 116a-j), conveyor belts 118, 120, a center conveyor 122, and a cutter bar assembly 124 that is fixed to the leading ends of the arms 114.
Referring now to FIGURE 3, arms 114 extend fore and aft and are pivotally coupled at their rear ends to frame 112. This arrangement permits them to pivot about a substantially horizontal and laterally extending axis 126 with respect to frame 112. This pivotal movement permits the front ends of arms 114 to move up and down with respect to frame 112 as the harvester traverses the ground.
Each arm has an associated spring 116 (iden6fred collectively as springs 116a-j) that is coupled to the arm and to the frame to provide an up will force on its associated arm 114, thereby reducing the farce applied by the arm downward on the ground.
Each arm supports a roller 128 that is supported at its front and rear ends on arm 114. Roller 128 is disposed generally parallel to arm 114 and is configured to roll about its longitudinal axis.
Arms 114 located on the left side of the header 104 centerline support a left side conveyor belt 118. Left side conveyor belt 118 is driven such that it carries material falling on its top surface inwards towards the center region of header 104.
Arms 114 located on the right side of the header 104 centeriine support a right side conveyor belt 120. Right side conveyor belt 120 is driven such that it carries material failing on its top surface inwards towards the center region of header 104.
Left side conveyor belt 110 and right side conveyor belt 120 are supported on rollers 128.
Cutter bar assembly 124 extends laterally across the width of the header 104 and is fixed to the front ends of arms 114. A lower portion 130 of cutter bar assembly 124 functions as a skid plate, sliding along the ground as vehicle transports header 104 across the field. A pordon of the weight of the arms, the conveyor belts, and the crop material riding on the conveyor belts is communicated to cutter bar assembly 124 and thence to the ground. The remainder of the weight is communicated to feeder house 106.
Cutter bar assembly 124 is flexible in the lateral direction to permit individual arms 114a-j to rise and fall somewhat independently of each other as the cutter bar assembly 124 follows the contours of the ground. This permits the header to more closely follow the contours of the ground. In tum, this dose ground-following ensures that the header 104 picks up all of the plant material bearing crop.
Each arm 114a-j is provided with a spring 116a-j that is coupled to the arm and to the frame 112 of the header 104. Spring 116 may be mechanical, hydraulic, or pneumatic. It applies an upward force to arm 114a j, reducing the downforce exerted by arm 114a j on the ground via cutter bar assembly 124.
Springs 11 6aj transfer the weight of their associated arms (and the loads thev carry) from the ground to frame 112.
The force that each spring 116aj applies is not the same, however, Springs 116 that are closer to the center of header 104 apply a greater upforce to their associated arms 114a j than springs 116a j located farther from the center of header 104. This differential additional upforce applied to arms 114a-j closer to the center of header 104 compensates for the increased weight of crop material on the conveyor belt 118, 120 supported on those arms. The weight of the plant material on the conveyor belts 118, 120 resting on arms 114a j changes as more and more crop accumulates on the conveyor belts. The weight of the plant material at the outer ends of the conveyor belts is relafively light. As the conveyor belt (supported on rollers 128) moves towards the lateral midpoint of the header 104, more and more plant material is cut by the cutter bar assembly 124 and falls on the conveyor belts. This builds up a thick layer of cut plant material on the conveyor belt that reaches a maximum thickness when the conveyor belt reaches the lateral midpoint of the header 104 and center conveyor 122. At this point, conveyor befts 118,120 on the left and right sides, respectlvely, of header 104 deposit their accumulated out plant material on center conveyor 122, which moves the cut plant material backward, through feeder house 106, and into vehicle 102 for further processing.
In order to maintain a relativeiy constant dowrtifarce across the entire width of the cutter bar assembly 124, each of the arms 114a j is counterbalanced by its associated spring 116aj such that each arm 114a-j applies the same downfvrce on the section of the cutter bar assembly 124 to which it is attached. This provides an even ground load across the width of the header 104.
There are several ways that the springs 116aj can be configured to provide different upforces to arms 114a j such as by adjusting their mounting iocations on the frame of the header or the arms, or by varying up reload to the springs.
Referring now to FIGURE 3, spring 116h has an upper end 132 that can be coupled to frame 112 at several different mountlng points 134 and a lower end 136 that can be coupled to arm 114h at several different mounting points 138.
Spring 116h has a preload adjuster 139, here shown as an adjustable screw on the barrel of the spring to vary the preload of the spring. By mounting the lower end of spring 116h closer to the pivot 141, the ground force at the end of arm 114h can be increased. By mounting the lower end of spring 116h farther from the pivot, the ground force at the end of arm 114h can be decreased. By mounting the upper end of spring 116h farther upward, the ground force at the end of arm 114h can be decreased. By mounting the upper end of spriing 116h farther downward, a ground force at the end of arm 114h can be increased. By increasing the spring preload on spring 116h, the ground force at the end of arm 114h can be decreased. By decreasing the spring preload one spring 116h, the ground force at the end of arm 114h can be increased. The arrangement of spring 116h and arm 114h in FIGURE 3 is typical of all the springs 116a-j anc arms 114a-j in header 104. The springs 116a j are individually adjusted to provide a greater upforce on the arms 714a j that are closer to the lateral midpoint or center of header 104 and to provide a smaller upforce on the arms 114a-j farther from the lateral midpoint or center of header 104.
Header 104 of FIGURES 1-3 is divided into several zones, comprising a first zone including the two outer arms 114a, 114b on the far left side of the header and the two outer arms 1141, 114J on the far right side of the header.
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second zone includes the two arms on each side of the header just inside the first zone, 114c, 714d, 114g, 114h, and the third zone including the two center arms 114e, 114f.
Springs 116a, 116b, 1161, 116j of the first zone are configured to provide a first upforce to their associated arms. Springs 116c, 116d, 116g, 116h are configured to provide a second upforce to their associated arms 114c, 114d, 114g, 114h that is greater than the first upforce applied to the arms in the first zone. This accommodates the additional weight of cut crop matter falling on conveyor belts 118, 120 as the belts move from the first zone to the second zone.
Springs 116e, 116f are configured to provide a third upforce to their associated arms 114e, 114f that is greater than the second upforce applied to the arms in the second zone. This accommodates the additional weight of cut crop matter falling on conveyor belts 118, 120 as the belts move from the second zone to the third zone.
In an alternative embodiment, each of the springs 116a j is configured to apply an upforce that is greater than the upforce applied to the arm immediately adjacent to it and farther away from the centerline of the vehicle. In other woros, the upforce applied by spring 116e to its arm is greater than that applied by spring 116d to its arm, which is greater than that applied by spring 116c to its arm, which is greater than that applied by spring 11 6b to its arm which is greater than that applied by spring 116a to its arm. An upforce applied by spring 1lSf to its arm is greater than the upfnrce applied by spring 116g to its arm, which is greater than the upforce applied by spring 116h to its arm, which is greater than the upforce applied by spring 116i to its arm, which is greater than the upforce applied by spring 116j.
One drawback of this arrangement is the need to mechanically adjust each spring 116a-116j for different crops and crop conditions. Any particular adjustment of springs 116a-J in FIGURES 1-3 anticipates a particular crop load on conveyor belts 11 S. 120. If the actual crop toad is different from this, the ground force exerted by each of arms 114 will not be ideal. Indeed, if a very large crop load is expected on conveyor belts 118, 120, the compensating upforce generated by springs 116a-j may be so great that the arms may actually be lifted above the ground if the crop is not as heavy as anticipated and therefore the compensating upforce generated by springs 116a j is too great.
To provide easier adjustment of the upforces generated by springs 116a j, other spring arrangements may be employed. In FIGURE 4, for example, each of springs 116a j is a hydraulic cylinder. Springs 116aJ in FIGURE 4 are all coupled to an accumulator that is gas charged and contains hydraulic fluid under pressure, This pressure is applied equally to all of the springs 116a-j in FIGURE
4. In one arrangement, springs 116a j exert an equal upforce on their associated arms 114a j to counterbalance the weight of the arm 114a j and the weight of the crop material on conveyor belts 118,120 that the arms support. In an altemative arrangement, springs 116a-j in FIGURE 4 are configured to exert different upforces on their associated arms 114a j to counterbalance the weight of the arm 114a-j and the weight of the crop material on conveyor belts 118, 120 that the arms support. In this altemative arrangement, the upforces exerted by springs 116a j on arms 114a-J may be divided into multiple zones, such as the three zones described above with regard to the header 104 of FIGURES 1-3.
Alterna6vely the upforces exerted by spnng$116a J on arms 114a-j may be arranged such that the upforce generated by spring 116e is greater than the force generated by spring 116d, which is greater than the force generated by spring 116c, which is greater than the force generated by spring 116b, which is greater than the force generated by spring 116a. The upforce generated by spring 116f is greater than the upforce generated by spring 116g, which is greater than the upforce generated by spring 11 Gh, which is greater than the upforce generated by spring 116i to its arm, which is greater than the upforce generated by spring 116j to its arm.
In order to generate different upforces when the hydraulic fluid pressure applied to each of the springs 116a j is the same, springs 116a-j may be made with different piston diameters, or ai'tematively may be coupled to arms 114a j and frame 112 of header 104 at different locations with different mechanical advantages, such as at the different locations along the arms and the frame shown in FIGURE 3.
In the arrangement of FIGURE 4, the amount of upforce generated by all of the springs 116a j can be varied simultaneously by filling or emptying the accumulator 132. A valve 134 is provided that is coupled to a hydraulic fluid supply 136 and a hydraulic fluid reservoir 138. The valve 134, when opened, can selectively empty hydraulic fluid from the accumulator 132 to the hydraulic fluid reservoir 138, or fill the accumulator 132 with hydraulic fluid from the hydraulic fluid supply 136. As the accumulator 132 is emptied, the pressure in the accumulator 132, and hence the pressure in each of springs 116a j decreases.
As the accumulator 132 is filled, the pressure in the accumulator 132 and hence the pressure in each of springs 116a j increases. The change in pressure in springs 116a j causes a proportional change in the upforce applied by the springs to arms 114a-j. Thus, by changing the fluid in the accumulator 132, all of the compensating upforces applied to arms 114a j are simultaneously and proportionally changed across the width of header 104.
Electronic control unit (ECU)140 is coupled to the valve 134 to selectively fill or empty the accumulator 132 under computer control. Electronic control unit 140 is preferably a microprocessor based digital computer including the memory circuit containing a program configured to perform all functions of the electronic cantrol unit described herein, A sensor 142 is coupled to the electronic control unit 140 to transmit to the electronic control unit 140 a value indicative of a desired compensating upforce to be generated by springs 116a J. In one embodiment, the sensor 142 is a rotor load sensor, responsive to and indicative of the load on a threshing rotor in the vehicle 102 (not shown). In another embodiment, the sensor is a strain gauge coupled to a rdtor drive element such as a rotor shaft or gear responsive to and indicative of the load on the rotor. In another embodiment, the sensor is a pressure sensor responsive to and in indicative of the hydraulic pressure in the hydraulic circuit driving the rotor. In another embodiment, the sensor is a pressure sensor responsive to and indicative of the hydraulic pressure in the hydraulic circuit that drives conveyor belts 118, 120. In another embodiment, the sensor is a load sensor responsive to and indicative of the weight of conveyor belts 118, 120. In any of these embodiments, the sensed parameter is indicative of the load on the harvester and hence the volume of crop material being harvested. The volume of crop material being harvested is indicative of the weight of the crop material. The weight of the crop material is indicative of the downforce exerted by arms 114a j and thus is indicative of the desired compensating upforce each spring 116a j needs to apply to its associated arm 114a-1 to maintain the downforce exerted by arms 114a J on the cutter bar (and hence the force the cutker bar and arms exert on the ground). The electronic control unit 140 is configured to monitor the sensor and to open the valve an aniount appropriate to maintain constant the downforce exerted by arms 114a j on the cutter bar (and hence the force the cutter bar and arms exert on the ground).
In another embodiment, the sensor 142 is configured to sense the position of an operator input device, for example a joystick, knob, dial, or lever, that the operator uses to directly command a desired compensating upforce. In this arrangement, the operator monitors the crop load and selects the desired upforce to be generated by springs 116a-j. Once the operator has selected the desired upforce, he adjusts the operator input device to indicate the desired upforce.
The sensor 142 is responsive to this change in the operator input device and signals the electronic control unit. The electronic control unit 140, in turn, is programmed to open or close the valve 134 as necessary to generate the desired upforce.
In this manner, and even while the vehicle is underway, the operator can simultaneously adjust the desired upforce of ali the springs 116a-J.
FIGURE 5 illustrates another embodiment of the system in which a different control circuit is provided to control the operation of springs 116a-j, the control circuit including three accumulators 144, 146, 148 to apply a different hydraulic pressure to three different groups of springs 116a j. This embodiment is the same as the embodiment of FIGURE 4 in all respects, except the control circuit includes three valves and three accumulators to apply three different pressures to three different groups of valves 116a j. In the embodiment of FIGURE 5, the control circuit includes a first accumulator 144 containing gas charged hydraulic fluid that is coupled to springs 116a, 116b, 116i, and 116j.
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second accumulator 146 containing gas charged hydraulic fluid is coupled to springs 116c, 116d, 116g, and 116h. A third accumulator 148 containing gas charged hydraulic fluid is coupled to springs 116e and 116f. These three groups of springs 116a j define three different zones of the header 104. These three accumulators are coupled to a first valve 150, a second valve 152, and a third valve 154, respectively that conduct hydraulic fluid to and from their respective accumulators 144, 146,148. Each of the three valves 144,146,148 are also coupled to the hydraulic fluid supply 136 and the hydraulic fluid reservoir 138. As in the example of FIGURE 4, the electronic control unit 140 opens and closes the valves responsive to the signal provided by the sensor 142 in order to maintain constant a desired downforce exerted by arms 114a j and the cutter bar on the ground. In the embodiment of FIGURE 5, however, the electronic control unit 140 is separately coupled to each of the three valves 150, 152, 154 such that it can change the hydraulic pressure in each of the three zones independently of the hydraulic pressure in the other zones.
Having described the preferred embodiment, it will hecome apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying clairris,
Related Aualications This invention claims priority to US Prov. Oat. App. Ser. No. 60/825,857, attorney docket number 17720, entitled "Header Float Arm Load Compensation", which was filed on September 15, 2006 by the same inventors.
Field of the Invention This invention relates generally to harvesters. More particularly, it relates to conveying systems for conveying cut crop material to the harvester vehicle.
Background_of the invention Harvesters have headers (typically called "Draper piatform5") that carry cut crop material on conveyor belts. These conveyor belts extend across the width of the header to a central discharge region of the header. The conveyor belts are supported on rollers that, in tum, are mounted on header float arms that are elongated and extend forwardly. These arms are pivotally mounted to a frame of the header. The forward ends of the header float arms are coupied to and support a cutter bar that extends across the width of the header.
The cutter bar and/or the forward ends of the arms skid across the surface of the ground as the harvester goes through the field harvesting crop. As the harvester is driven through the fieid, the ground rises and falls undemeath the header and the arms pivot up and down responsibly, thereby permitting the cutter bar to follow the contours of the ground more closely.
If the cutter bar and/or the front ends of the arms apply too much pressure to the ground they will dig into the ground and be damaged. Controlling the downforce is therefore important in keeping the header and harvester opera4ng properly.
To reduce the downforce applied by the header to the ground, each arm is partially supported by a hydrauiic, pneumatic, or mechanical spring. The springs are coupled to the frame of the header and transmit some of the crop weight to the frame. They do this by exerting a lifting or "up" force on the arms that counteracts the weight of the arms and the addifional downforce exerted on the arms by the cut crop material that falls backward onto the conveyor belts after it is cut by the cutter bar. The springs transfer some of the weight of the header float arms and cut crop material to the feeder house on which the header is supported and transfer the weight off the cutter bar and ground.
The cut crop material is not evenly distributed across the width of the header conveyors. The crop is cut by the cutter bar across the entire front of the header and then falls backwards onto the conveyor belts, a left conveyor belt and a right conveyor belt. The left conveyor belt carries the cut crop material from the left side of the header to the center section of the header, and the right conveyor belt carries the cut crop material from the right side of the header to the center section of the header. Once the cut crop material reaches the center section of the header, the left and right conveyors dump the cut crop meterial into a center conveyor that carries the cut crop material backwards, through the feeder house, and into the self-propelled vehicle pordon of the harvester.
Depending upon its position across the front of the header, each header float arm needs a different amount of upward counterbalancing force in order that each header float arm exerts the same downforce against the ground that all the other header float arms do. In the ideal situa6on, each header float arm provides the same, optimal downforce against the ground.
In order for each header float arm to provide the same downforce against the ground, each spring must apply a different upforce to Its associated header float arms. This Is necessary since different pordons of the conveyor (and hence each header float arm) support different quantities of cut crop material. As the conveyors move laterally across the width of the header toward the lateral midpoint of the header, more and more cut crop material falls onto the conveyor belt. And the header float arms closer to the lateral midpoint of the header carry a greater and greater weight of cut crop material. This additional crop material resting on the header float arms closer to the lateral midpoint or center of the header means that the header float enns closer to the lateral midpoint require a greater counterbalancing upforce - the force exerted by the springs - if each header float arm is to apply a constant downforce against the ground.
What is needed, therefore, is a control system for applying to each header float arm in the header a counterbalancing upforce that is appropriate to support the crop load and to maintain constant the downforce exerted by each header fioat arm against the ground (either directly, or through the cutter bar). It is an object of this invention to provide such a system.
Summary of the Invention in accordance with the first aspect of the invention of float arm Ioad compensation system for a header of an agricultural harvester is provided, comprising a header frame; a plurality of header float arms pivotally coupled to the header frame; a cutter bar fixed to fonivard ends of the plurality of header float arms; at least one conveyor belt supported on the plurality of header float arms and configured to traverse the header perpendicular to the direction of travel of the header, wherein the conveyor belt is further configured to receive crop material cut by the cutter bar; and a plurality of springs, wherein each spring is coupied to an associated header float arm of the plurality of header float arms to exert a force on the associated header float arm compensating for the weight of cut crop material supported by the associated header float arm.
The springs of the plurality of springs that support float arms closer to the lateral midpoint of the header may be configured to exert a greater upforce on their associated header float arms than other springs of the plurality of springs that support float arms farther from the lateral midpoint of the header. The plurality of springs may be configured to maintain constant the downforce exerted by their associated header float arms against the ground across a width of the header. The load compensation system may further include a control circuit configured to monitor an operational parameter of the agricultural harvester indicative of the load on the at least one conveyor belt. The control circuit may monitor an operational parameter indicative of a load on the rotor of the harvester. The control circuit may be configured to automatically change the forces exerted by the plurality of springs on their associated header float arms in response to changes in the operational parameter. The load compensation system may further include an accumulator containing gas charged hydraulic fluid coupled to the plurality of springs. The load compensation system may further include a valve configured to simultaneously change the force is applied by the plurality of springs by filling and emptying the accumulator. The load compensation system may further include at least first and second accumulators containing hydraulic fluid under pressure, wherein the first accumulator is coupled to a first group of springs of the plurality of springs, and wherein the second accumulator Is coupled to a second group of springs of the plurality of springs. The plurality of springs may be mechanical springs. The mechanical springs may be coil springs.
Brief Desrxigtion f the Drawings FIGURE 1 is a plan view of a harvester having a header in the form of a Draper platform in accordance with the present invention.
FIGURE 2 is a side view of the harvester of FIGURE 1.
FIGURE 3 is a fragmentary cross-sectional view of the header of FIGURES 1-2 taken at section line 2-2 in FIGURE 1.
FIGURE 4 is a schematic diagram of the header of FIGURES 1-3 with alternative springs and a controi circuit for controlling the alternative springs.
FIGURE 5 is a schematic diagram of the header of FIGURE 4 with an aiternati:ve control circuit for controliing the aiternative springs.
Descriotion of the Preferred Embodiments An "upforce", as that term is used herein, refers to a force applied to a header float arm that tends to lift the forward end of the header float arm upward and away from the ground thereby reducing the force of the header float arm against the ground. It does not imply or require that the force itself be directed upward at its point of application to the header float arm. Indeed, depending upon the geometry of the header float arm, the force may be applied to the header float arm in any direction and at any point along the arm, Referring now to FIGURES 1-2, a combine harvester 100 is illustrated, comprising a vehide 102 that is wheeled and self-propelled, and also comprising a header 104 which is a Draper platform that is mounted on the front of the vehicle M.
Vehicle 102 further comprises a feeder house 106 that is pivotally coupled to the front of chassis 108 of vehicle 102. Header 104 is supported on the front of feeder house 106.
Header 104 comprises a frame 112, a plurality of arms 114 (identified collectively as header float arms 114a j), a plurality of springs 116 (identified as springs 116a-j), conveyor belts 118, 120, a center conveyor 122, and a cutter bar assembly 124 that is fixed to the leading ends of the arms 114.
Referring now to FIGURE 3, arms 114 extend fore and aft and are pivotally coupled at their rear ends to frame 112. This arrangement permits them to pivot about a substantially horizontal and laterally extending axis 126 with respect to frame 112. This pivotal movement permits the front ends of arms 114 to move up and down with respect to frame 112 as the harvester traverses the ground.
Each arm has an associated spring 116 (iden6fred collectively as springs 116a-j) that is coupled to the arm and to the frame to provide an up will force on its associated arm 114, thereby reducing the farce applied by the arm downward on the ground.
Each arm supports a roller 128 that is supported at its front and rear ends on arm 114. Roller 128 is disposed generally parallel to arm 114 and is configured to roll about its longitudinal axis.
Arms 114 located on the left side of the header 104 centerline support a left side conveyor belt 118. Left side conveyor belt 118 is driven such that it carries material falling on its top surface inwards towards the center region of header 104.
Arms 114 located on the right side of the header 104 centeriine support a right side conveyor belt 120. Right side conveyor belt 120 is driven such that it carries material failing on its top surface inwards towards the center region of header 104.
Left side conveyor belt 110 and right side conveyor belt 120 are supported on rollers 128.
Cutter bar assembly 124 extends laterally across the width of the header 104 and is fixed to the front ends of arms 114. A lower portion 130 of cutter bar assembly 124 functions as a skid plate, sliding along the ground as vehicle transports header 104 across the field. A pordon of the weight of the arms, the conveyor belts, and the crop material riding on the conveyor belts is communicated to cutter bar assembly 124 and thence to the ground. The remainder of the weight is communicated to feeder house 106.
Cutter bar assembly 124 is flexible in the lateral direction to permit individual arms 114a-j to rise and fall somewhat independently of each other as the cutter bar assembly 124 follows the contours of the ground. This permits the header to more closely follow the contours of the ground. In tum, this dose ground-following ensures that the header 104 picks up all of the plant material bearing crop.
Each arm 114a-j is provided with a spring 116a-j that is coupled to the arm and to the frame 112 of the header 104. Spring 116 may be mechanical, hydraulic, or pneumatic. It applies an upward force to arm 114a j, reducing the downforce exerted by arm 114a j on the ground via cutter bar assembly 124.
Springs 11 6aj transfer the weight of their associated arms (and the loads thev carry) from the ground to frame 112.
The force that each spring 116aj applies is not the same, however, Springs 116 that are closer to the center of header 104 apply a greater upforce to their associated arms 114a j than springs 116a j located farther from the center of header 104. This differential additional upforce applied to arms 114a-j closer to the center of header 104 compensates for the increased weight of crop material on the conveyor belt 118, 120 supported on those arms. The weight of the plant material on the conveyor belts 118, 120 resting on arms 114a j changes as more and more crop accumulates on the conveyor belts. The weight of the plant material at the outer ends of the conveyor belts is relafively light. As the conveyor belt (supported on rollers 128) moves towards the lateral midpoint of the header 104, more and more plant material is cut by the cutter bar assembly 124 and falls on the conveyor belts. This builds up a thick layer of cut plant material on the conveyor belt that reaches a maximum thickness when the conveyor belt reaches the lateral midpoint of the header 104 and center conveyor 122. At this point, conveyor befts 118,120 on the left and right sides, respectlvely, of header 104 deposit their accumulated out plant material on center conveyor 122, which moves the cut plant material backward, through feeder house 106, and into vehicle 102 for further processing.
In order to maintain a relativeiy constant dowrtifarce across the entire width of the cutter bar assembly 124, each of the arms 114a j is counterbalanced by its associated spring 116aj such that each arm 114a-j applies the same downfvrce on the section of the cutter bar assembly 124 to which it is attached. This provides an even ground load across the width of the header 104.
There are several ways that the springs 116aj can be configured to provide different upforces to arms 114a j such as by adjusting their mounting iocations on the frame of the header or the arms, or by varying up reload to the springs.
Referring now to FIGURE 3, spring 116h has an upper end 132 that can be coupled to frame 112 at several different mountlng points 134 and a lower end 136 that can be coupled to arm 114h at several different mounting points 138.
Spring 116h has a preload adjuster 139, here shown as an adjustable screw on the barrel of the spring to vary the preload of the spring. By mounting the lower end of spring 116h closer to the pivot 141, the ground force at the end of arm 114h can be increased. By mounting the lower end of spring 116h farther from the pivot, the ground force at the end of arm 114h can be decreased. By mounting the upper end of spring 116h farther upward, the ground force at the end of arm 114h can be decreased. By mounting the upper end of spriing 116h farther downward, a ground force at the end of arm 114h can be increased. By increasing the spring preload on spring 116h, the ground force at the end of arm 114h can be decreased. By decreasing the spring preload one spring 116h, the ground force at the end of arm 114h can be increased. The arrangement of spring 116h and arm 114h in FIGURE 3 is typical of all the springs 116a-j anc arms 114a-j in header 104. The springs 116a j are individually adjusted to provide a greater upforce on the arms 714a j that are closer to the lateral midpoint or center of header 104 and to provide a smaller upforce on the arms 114a-j farther from the lateral midpoint or center of header 104.
Header 104 of FIGURES 1-3 is divided into several zones, comprising a first zone including the two outer arms 114a, 114b on the far left side of the header and the two outer arms 1141, 114J on the far right side of the header.
A
second zone includes the two arms on each side of the header just inside the first zone, 114c, 714d, 114g, 114h, and the third zone including the two center arms 114e, 114f.
Springs 116a, 116b, 1161, 116j of the first zone are configured to provide a first upforce to their associated arms. Springs 116c, 116d, 116g, 116h are configured to provide a second upforce to their associated arms 114c, 114d, 114g, 114h that is greater than the first upforce applied to the arms in the first zone. This accommodates the additional weight of cut crop matter falling on conveyor belts 118, 120 as the belts move from the first zone to the second zone.
Springs 116e, 116f are configured to provide a third upforce to their associated arms 114e, 114f that is greater than the second upforce applied to the arms in the second zone. This accommodates the additional weight of cut crop matter falling on conveyor belts 118, 120 as the belts move from the second zone to the third zone.
In an alternative embodiment, each of the springs 116a j is configured to apply an upforce that is greater than the upforce applied to the arm immediately adjacent to it and farther away from the centerline of the vehicle. In other woros, the upforce applied by spring 116e to its arm is greater than that applied by spring 116d to its arm, which is greater than that applied by spring 116c to its arm, which is greater than that applied by spring 11 6b to its arm which is greater than that applied by spring 116a to its arm. An upforce applied by spring 1lSf to its arm is greater than the upfnrce applied by spring 116g to its arm, which is greater than the upforce applied by spring 116h to its arm, which is greater than the upforce applied by spring 116i to its arm, which is greater than the upforce applied by spring 116j.
One drawback of this arrangement is the need to mechanically adjust each spring 116a-116j for different crops and crop conditions. Any particular adjustment of springs 116a-J in FIGURES 1-3 anticipates a particular crop load on conveyor belts 11 S. 120. If the actual crop toad is different from this, the ground force exerted by each of arms 114 will not be ideal. Indeed, if a very large crop load is expected on conveyor belts 118, 120, the compensating upforce generated by springs 116a-j may be so great that the arms may actually be lifted above the ground if the crop is not as heavy as anticipated and therefore the compensating upforce generated by springs 116a j is too great.
To provide easier adjustment of the upforces generated by springs 116a j, other spring arrangements may be employed. In FIGURE 4, for example, each of springs 116a j is a hydraulic cylinder. Springs 116aJ in FIGURE 4 are all coupled to an accumulator that is gas charged and contains hydraulic fluid under pressure, This pressure is applied equally to all of the springs 116a-j in FIGURE
4. In one arrangement, springs 116a j exert an equal upforce on their associated arms 114a j to counterbalance the weight of the arm 114a j and the weight of the crop material on conveyor belts 118,120 that the arms support. In an altemative arrangement, springs 116a-j in FIGURE 4 are configured to exert different upforces on their associated arms 114a j to counterbalance the weight of the arm 114a-j and the weight of the crop material on conveyor belts 118, 120 that the arms support. In this altemative arrangement, the upforces exerted by springs 116a j on arms 114a-J may be divided into multiple zones, such as the three zones described above with regard to the header 104 of FIGURES 1-3.
Alterna6vely the upforces exerted by spnng$116a J on arms 114a-j may be arranged such that the upforce generated by spring 116e is greater than the force generated by spring 116d, which is greater than the force generated by spring 116c, which is greater than the force generated by spring 116b, which is greater than the force generated by spring 116a. The upforce generated by spring 116f is greater than the upforce generated by spring 116g, which is greater than the upforce generated by spring 11 Gh, which is greater than the upforce generated by spring 116i to its arm, which is greater than the upforce generated by spring 116j to its arm.
In order to generate different upforces when the hydraulic fluid pressure applied to each of the springs 116a j is the same, springs 116a-j may be made with different piston diameters, or ai'tematively may be coupled to arms 114a j and frame 112 of header 104 at different locations with different mechanical advantages, such as at the different locations along the arms and the frame shown in FIGURE 3.
In the arrangement of FIGURE 4, the amount of upforce generated by all of the springs 116a j can be varied simultaneously by filling or emptying the accumulator 132. A valve 134 is provided that is coupled to a hydraulic fluid supply 136 and a hydraulic fluid reservoir 138. The valve 134, when opened, can selectively empty hydraulic fluid from the accumulator 132 to the hydraulic fluid reservoir 138, or fill the accumulator 132 with hydraulic fluid from the hydraulic fluid supply 136. As the accumulator 132 is emptied, the pressure in the accumulator 132, and hence the pressure in each of springs 116a j decreases.
As the accumulator 132 is filled, the pressure in the accumulator 132 and hence the pressure in each of springs 116a j increases. The change in pressure in springs 116a j causes a proportional change in the upforce applied by the springs to arms 114a-j. Thus, by changing the fluid in the accumulator 132, all of the compensating upforces applied to arms 114a j are simultaneously and proportionally changed across the width of header 104.
Electronic control unit (ECU)140 is coupled to the valve 134 to selectively fill or empty the accumulator 132 under computer control. Electronic control unit 140 is preferably a microprocessor based digital computer including the memory circuit containing a program configured to perform all functions of the electronic cantrol unit described herein, A sensor 142 is coupled to the electronic control unit 140 to transmit to the electronic control unit 140 a value indicative of a desired compensating upforce to be generated by springs 116a J. In one embodiment, the sensor 142 is a rotor load sensor, responsive to and indicative of the load on a threshing rotor in the vehicle 102 (not shown). In another embodiment, the sensor is a strain gauge coupled to a rdtor drive element such as a rotor shaft or gear responsive to and indicative of the load on the rotor. In another embodiment, the sensor is a pressure sensor responsive to and in indicative of the hydraulic pressure in the hydraulic circuit driving the rotor. In another embodiment, the sensor is a pressure sensor responsive to and indicative of the hydraulic pressure in the hydraulic circuit that drives conveyor belts 118, 120. In another embodiment, the sensor is a load sensor responsive to and indicative of the weight of conveyor belts 118, 120. In any of these embodiments, the sensed parameter is indicative of the load on the harvester and hence the volume of crop material being harvested. The volume of crop material being harvested is indicative of the weight of the crop material. The weight of the crop material is indicative of the downforce exerted by arms 114a j and thus is indicative of the desired compensating upforce each spring 116a j needs to apply to its associated arm 114a-1 to maintain the downforce exerted by arms 114a J on the cutter bar (and hence the force the cutker bar and arms exert on the ground). The electronic control unit 140 is configured to monitor the sensor and to open the valve an aniount appropriate to maintain constant the downforce exerted by arms 114a j on the cutter bar (and hence the force the cutter bar and arms exert on the ground).
In another embodiment, the sensor 142 is configured to sense the position of an operator input device, for example a joystick, knob, dial, or lever, that the operator uses to directly command a desired compensating upforce. In this arrangement, the operator monitors the crop load and selects the desired upforce to be generated by springs 116a-j. Once the operator has selected the desired upforce, he adjusts the operator input device to indicate the desired upforce.
The sensor 142 is responsive to this change in the operator input device and signals the electronic control unit. The electronic control unit 140, in turn, is programmed to open or close the valve 134 as necessary to generate the desired upforce.
In this manner, and even while the vehicle is underway, the operator can simultaneously adjust the desired upforce of ali the springs 116a-J.
FIGURE 5 illustrates another embodiment of the system in which a different control circuit is provided to control the operation of springs 116a-j, the control circuit including three accumulators 144, 146, 148 to apply a different hydraulic pressure to three different groups of springs 116a j. This embodiment is the same as the embodiment of FIGURE 4 in all respects, except the control circuit includes three valves and three accumulators to apply three different pressures to three different groups of valves 116a j. In the embodiment of FIGURE 5, the control circuit includes a first accumulator 144 containing gas charged hydraulic fluid that is coupled to springs 116a, 116b, 116i, and 116j.
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second accumulator 146 containing gas charged hydraulic fluid is coupled to springs 116c, 116d, 116g, and 116h. A third accumulator 148 containing gas charged hydraulic fluid is coupled to springs 116e and 116f. These three groups of springs 116a j define three different zones of the header 104. These three accumulators are coupled to a first valve 150, a second valve 152, and a third valve 154, respectively that conduct hydraulic fluid to and from their respective accumulators 144, 146,148. Each of the three valves 144,146,148 are also coupled to the hydraulic fluid supply 136 and the hydraulic fluid reservoir 138. As in the example of FIGURE 4, the electronic control unit 140 opens and closes the valves responsive to the signal provided by the sensor 142 in order to maintain constant a desired downforce exerted by arms 114a j and the cutter bar on the ground. In the embodiment of FIGURE 5, however, the electronic control unit 140 is separately coupled to each of the three valves 150, 152, 154 such that it can change the hydraulic pressure in each of the three zones independently of the hydraulic pressure in the other zones.
Having described the preferred embodiment, it will hecome apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying clairris,
Claims (11)
1. A float arm load compensation system for a header of an agricultural harvester, comprising;
a header frame;
a plurality of header float arms pivotally coupled to the header frame;
a cutter bar fixed to forward ends of the plurality of header float arms;
at least one conveyor belt supported on the plurality of header float arms and configured to traverse the header perpendicular to the direction of travel of the header, wherein the conveyor belt is further configured to receive crop material cut by the cutter bar; and a plurality of springs, wherein each spring is coupled to an associated header float arm of the plurality of header float arms to exert a force on the associated header float arm compensating for the weight of cut crop material supported by the associated header float arm.
a header frame;
a plurality of header float arms pivotally coupled to the header frame;
a cutter bar fixed to forward ends of the plurality of header float arms;
at least one conveyor belt supported on the plurality of header float arms and configured to traverse the header perpendicular to the direction of travel of the header, wherein the conveyor belt is further configured to receive crop material cut by the cutter bar; and a plurality of springs, wherein each spring is coupled to an associated header float arm of the plurality of header float arms to exert a force on the associated header float arm compensating for the weight of cut crop material supported by the associated header float arm.
2. The load compensation system of claim 1, wherein springs of the plurality of springs that support float arms closer to the lateral midpoint of the header are configured to exert a greater upforce on their associated header float arms than other springs of the plurality of springs that support float arms farther from the lateral midpoint of the header.
3. The load compensation system of claim 1, wherein the plurality of springs are configured to maintain constant the downforce exerted by their associated header float arms against the ground across a width of the header.
4. The load compensation system of claim 1, further comprising a control circuit configured to monitor an operational parameter of the agricultural harvester indicative of the load on the at least one conveyor belt.
5. The load compensation system of claim 4, wherein the control circuit monitors an operational parameter indicative of a load on the rotor of the harvester.
6. The load compensation system of claim 4, wherein the control circuit is configured to automatically change the forces exerted by the plurality of springs on their associated header float arms in response to changes in the operational parameter.
7. The load compensation system of claim 1, further comprising an accumulator containing gas charged hydraulic fluid coupled to the plurality of springs.
8. The load compensation system of claim 1, further comprising a valve configured to simultaneously change the force is applied by the plurality of springs by filling and emptying the accumulator.
9. The load compensation system of claim 1, further comprising at least first and second accumulators containing hydraulic fluid under pressure, wherein the first accumulator is coupled to a first group of springs of the plurality of springs, and wherein the second accumulator is coupled to a second group of springs of the plurality of springs.
10. The load compensation system of claim 1, wherein the plurality of springs are mechanical springs.
11. The load compensation system of claim 10, wherein the mechanical springs are coil springs.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2606003A CA2606003C (en) | 2007-10-09 | 2007-10-09 | Header float arm load compensation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2606003A CA2606003C (en) | 2007-10-09 | 2007-10-09 | Header float arm load compensation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2606003A1 true CA2606003A1 (en) | 2009-04-09 |
| CA2606003C CA2606003C (en) | 2014-11-25 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2606003A Active CA2606003C (en) | 2007-10-09 | 2007-10-09 | Header float arm load compensation |
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| Country | Link |
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| CA (1) | CA2606003C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130305676A1 (en) * | 2011-11-16 | 2013-11-21 | Macdon Industries Ltd. | Swather with Float Assembly |
| EP3850939A1 (en) * | 2020-01-14 | 2021-07-21 | CNH Industrial Belgium N.V. | Active backsheet for a grain header |
-
2007
- 2007-10-09 CA CA2606003A patent/CA2606003C/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130305676A1 (en) * | 2011-11-16 | 2013-11-21 | Macdon Industries Ltd. | Swather with Float Assembly |
| US8745964B2 (en) * | 2011-11-16 | 2014-06-10 | Macdon Industries Ltd | Swather with float assembly and disconnect coupling |
| EP3850939A1 (en) * | 2020-01-14 | 2021-07-21 | CNH Industrial Belgium N.V. | Active backsheet for a grain header |
| US11412659B2 (en) | 2020-01-14 | 2022-08-16 | Cnh Industrial America Llc | Active backsheet for a grain header |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2606003C (en) | 2014-11-25 |
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