Patent Application
20130032363
The field relates to ground working implements with row units engaging the ground and in particular to a supplemental down force system for the ground engaging row units.
Ground engaging implements typically have tools, or other devices that engage and work the ground. For example, a typical row crop planter has a number of planting row units that put seed in the ground as the machine is, moved over a field. Each row unit is equipped with a furrow opener that opens a furrow in the soil into which seed is deposited and then covered. A depth gauge device, typically a gauge wheel, is set at a predetermined position to control how deep the opener cuts the furrow into the soil. The row units are mounted to the machine frame for vertical movement relative to the frame so that the row units can follow the ground contours. The row units must have sufficient weight to force the opener fully into the soil to the desired depth. More weight is needed for firmer soils than for light, sandy soils. The row units may not have sufficient weight to fully penetrate the opener into the soil. To overcome this problem, row units are typically provided with a down force system that transfers weight from the machine frame to the row unit. The downforce system may be a mechanical spring connected between the frame and row unit to force the row unit down. Such systems are adjustable so that the operator can adjust the amount of added or supplemental down force.
More recently, mechanical springs have been replaced with pneumatic-down force actuators or cylinders. The amount of supplemental down force applied to the row unit is varied by changing the air pressure in the actuators. This is accomplished by a pneumatic control circuit connected to a supply of compressed air from an air compressor. Adjustment of the down force with a pneumatic system is much easier then manually changing the setting of the mechanical springs on each row unit.
Still further improvements in down force systems provide a closed loop feed back control of the pneumatic actuators. Three to five row units are equipped with load sensors that measure the soil reaction load applied to the gauge wheels or other depth gauge device. If the opener is fully penetrating, the gauge wheel will be in contact with the soil. Typically some load greater than zero is desired on the gauge wheel to ensure that the gauge wheel stays in contact with the ground at all times. The load on the gauge wheels will vary over a range due to the dynamics conditions in which the planter is operating. Thus a nominal load on the gauge wheel is necessary so that in the dynamic range, the load on the gauge wheel does not go to or below zero. The operator selects the magnitude of the desired force on the gauge wheels and the control system increases or decreases the pressure in the pneumatic cylinders to produce this desired force. Some systems include, in addition to the down force cylinder, an up force actuator or cylinder to apply an upward force on the row unit when the weight of the row unit exceeds the needed down force. Alternatively, an up lift cylinder can be used in combination with a mechanical spring down force system. The springs are set to produce more down force than needed and the up lift cylinder is used to counter act the down force to fine-tune the total load on the row unit.
The loads sensed by the three to five sensors are averaged to determine the needed supplemental down force. The pneumatic actuators are then all supplied with the same air pressure to produce the desired soil reaction force on the gauge wheels. However, due to the geometry of the planting machine, all row units may not need to the same air pressure in the actuators to produce the needed down force.
A supplemental downforce system is provided for a ground working implement having a frame and a plurality of ground engaging row units movably mounted to the frame for up and down movement relative to the frame. The downforce system includes at least one actuator between the frame and each row unit to apply an up or down force to each row unit. The actuators are assigned to one group of at least two groups of actuators. A control system controls the down force applied by each group of actuators separately so that each group of actuators is given the amount of supplemental down force that group of row units needs. In a closed loop feedback system, at least one row unit in each group of row units is equipped with a load sensor so that feed back of the soil reaction force on the row unit is supplied to the control system.
With reference to
A number of row units 30 are mounted to the draw bar 16. The row units form ground engaging tools that work in the soil as the machine is operated. Row units 30A form a front rank of row units mounted to the main center section 18 of the frame, not all of which are visible in
With reference to
A seed meter 64 is also carried by row unit frame 50. Seed meter 64 receives seed from a seed hopper 66. The seed meter drive is not shown; numerous types of drive mechanisms are well known. Seed meter 64 delivers seeds sequentially to a seed tube 68 through which the seed falls by gravity to the furrow 58. The seed meter 64 and seed tube 68 form a product dispenser to dispense product to the furrow 58.
A pair of closing wheels 70 follows behind the gauge wheels and are positioned generally in line with double disc furrow opener 56. Closing wheels 70 are preferably biased in a downward direction and have a peripheral edge with a shape which may vary, depending upon the application. Closing wheels 70 push soil back into the furrow 58 to cover the seed or product deposited therein and may also pack the soil.
A supplemental down force system includes, on the row unit 30E, a down force actuator 100 in the form of an adjustable pneumatic down force cylinder 102. The cylinder 102 acts between the draw bar, that is, the right wing section 22, and the parallel links 52 to apply down force on the row unit and the row unit components engaging the soil. The down force applied by the cylinder 102 ensures that there is sufficient force to fully insert the double disc furrow opener 56 into the soil, forming the furrow 58 to the desired depth. The down force applied to the row unit by the cylinder 102 is shown by the arrow FD. While only a down force cylinder is shown, there may also be an up force, or lift cylinder. In other systems, there may be an adjustable spring providing a down force together with a pneumatic lift cylinder to fine tune the total down force on the row unit. In such a system, the spring would be set to provide a down force that is greater than what is needed at any time and the lift cylinder would be controlled to counter-act a portion of the spring down force to produce a desired total down force. Arrow FD represents the entire downforce applied to the row unit.
The row unit weight also produces a down force shown by the arrow FG acting through the center of gravity of the row unit. The force FG varies over time as the level of product in the seed hopper 66 and other hoppers (not shown) changes during operation of the planter 10. (The hopper 66 is relatively small and the amount of product therein does not change appreciably. However, other row unit configurations may have larger product hoppers.) These two downward acting forces, FD and FG are counter-acted by upward forces acting on the row unit. The opener penetrates the soil and has a force FO acting upward on the opener. When the opener 56 is fully penetrating, the gauge wheels 62 will be in contact with the soil and a soil reaction force FR acts upward on the gauge wheels. An additional upward force on the row unit is the force FC acting on the closing wheels 70. Other attachments to the row unit, not shown, such as a coulter or row cleaner will also generate an upward force on the row unit. In systems with a lift cylinder, the down force FD, may at times, be positive and at times negative, meaning it may be directed downward or upward. The force FO will vary during operation with the dynamics of operation, i.e. bouncing in the field, and also with changing soil conditions. For example, at the top of a hill, the soil may be dryer and harder, requiring more force FO to fully penetrate the opener as compared to wetter, softer, soil at the bottom of a hill. If the down force FD is fixed, such as with mechanical springs, when the opener force FO increases, the gauge wheel soil reaction force FR will decrease.
A minimum soil reaction force FR acting on the gauge wheels 62 is desired to have confidence that the opener is fully penetrating the soil to the desired depth. If the reaction force FR acting on the gauge wheel is zero, the gauge wheel is not touching the soil. This occurs when the opener is not fully penetrating the soil to the desired depth. Thus, some level of reaction force FR greater than zero is desired to be maintained to ensure there is full penetration by the opener.
The pressure in the cylinders is controlled by an electronic controller 106 that connects to an actuation system 114. An input device 104 allows the operator to command the system. In an open-loop system, the operator the input device to input commands to increase or decrease the cylinder inflation pressures. The controller 106 then implements the command by actuating the appropriate valves, in the actuation system 114. The operator first inflates the pneumatic cylinders 102 to a desired inflation pressure that will keep the opener fully penetrating. The operator will observe the row unit performance and make adjustments to the cylinder inflation. In the open loop system, the pneumatic cylinders provide an advantage over mechanical springs in that adjustment only requires activation through the input device 104 and not manual adjustment of springs on each row unit.
In a closed-loop system, the operator uses the input device 104 to input into the controller 106 a desired reaction force FR to be maintained on the gauge wheels. The controller 116 operates an actuation system 114 to change the air pressure in the cylinders 102 in response to changes in the opener force Fo. Changes in force FO are determined by measuring the soil reaction force FR acting on the gauge wheels. The magnitude of the force FR is measured by a sensor or load cell that can be located in a variety of locations on the row unit. One example is a load sensor pin 108 in the gauge wheel depth adjustment link 110. Adjustment link 110 bears against and resists upward movement of the pivot arm 112 carrying the gauge wheels 62. A suitable load sensor pin is shown in WO2008/086283 A2. Multiple row units are equipped with a load sensor but not all row units need a sensor. A typical current production down force system may have three to five row units equipped with load sensors. The loads sensed by the sensors are averaged to determine the needed supplemental down force. The pneumatic cylinders 102 are then all supplied with the same air pressure to produce the desired reaction force FR on the gauge wheels. But not all row units need the same supplemental down force. Differences may be caused by different soil conditions experienced by different parts of the machine. Other differences in the needed supplemental down force may be caused by the planter frame geometry. For example, the front rank row units may need a different air pressure than do the rear ranks of row units to produce the desired down force. The wing section row units may need a different down force than the center main section row units.
The controller 106 and the actuation system 114 are configured to control the supplemental down force in two or more groupings of row units. In the following example two groups of row units are controlled separately; the front rank row units and the rear rank row units. Those skilled in the art will appreciate that any number of row unit groups can be provided. The actuation system 114 is shown and described in connection with
At least one row unit in each group of row units will have a load sensor 108 for determining the load FR acting on the gauge wheel. If more than one sensor is provide in the rank, then the values of the load sensors are averaged and the average value used to determine the air pressure to apply to the cylinders 102 of that rank of row units.
The down force system includes the actuators or cylinders 102, either down force or up force or both, together with a control system 98. The control system 98 has an input device 104, an electronic controller 106 and an actuation system 114 to implement the commands from the controller, typically opening and closing valves. It is desirable to include a display 116 to convey information back to the operator such as the commanded load and the measured loads. While the control system is shown with separate components, they can be combined into one or more components with appropriate connections.
A closed-loop control system has been described above. In an open-loop system without the load sensors 108, the operator monitors the furrow opening and closing and manually actuates the pneumatic system valves to adjust the air pressure in the cylinders 102 of each rank separately. Obviously, this manual adjustment will be done infrequently as compared to the continuously monitored closed-loop system.
Those skilled in the art will appreciate that any number of row unit groups can be provided for. The only limitation is one of cost versus benefit. At some point, the cost of adding another group will outweigh the benefit in terms of increased yield from improved planter performance.
The supplemental down force system has been shown and described as a pneumatic system. However, other systems can be used in place of pneumatic such as hydraulics or electro-mechanical systems.
A towed implement has been shown and described. It is apparent that this could be a self-propelled machine instead of a towed implement. No distinction or limitation is intended by the use of the term “implement.”
The supplemental down force system has been described in the context of a row crop planter. However, the down force system can be applied to any agricultural implement having ground working tools such as a grain drill, air seeder, tillage tool, nutrient applicator, etc and can also be applied to non-agricultural machines that engage and work the ground.
Having described the system, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.
