Patent Description:
Various factors affect seeding performance and thus crop yields. One such factor is the amount of downforce applied to the row unit for engaging the various ground-engaging implements of the row unit with the soil. Planters are known to have row units with downforce actuators that can provide fixed or adjustable downforce while planting.

<CIT> discloses a seeding implement with a down pressure sensing and adjustment system. Sensors, which may include a frame accelerometer, an opener accelerometer, inclinometers and/or hydraulic sensors provide sensor signals to a controller which are used to control the down force applied by a hydraulic cylinder to maintain a desired seed depth and furrow formation without overstressing the gauge wheel.

The applicant has determined that it may be beneficial to provide seeding implements that can safely navigate over soil obstructions while maintaining adequate downforce. The invention proposes a row unit according to claim <NUM> and a method according to claim <NUM>. In one aspect, the disclosure provides a row unit for a seeding machine operable to plant seeds into soil. A frame supports a furrow opener for opening a furrow in the soil, a gauge wheel for rolling atop the soil, a seed dispenser for dispensing seeds into the furrow, and a furrow closer for closing the furrow. A row unit downforce actuator is operable to push the row unit frame toward the soil to adjustably control soil engagement forces for the furrow opener, the gauge wheel, and the furrow closer. An acceleration sensor is configured to detect accelerations of the row unit. A controller is in communication with the acceleration sensor and the row unit downforce actuator, and the controller is programmed with an algorithm to maintain a target downforce value during operation of the row unit. The controller is further programmed to abandon the target downforce value and relieve the row unit downforce actuator to transition to a floating state that enables the row unit to float over soil obstructions in response to a signal from the acceleration sensor indicative of acceleration of the row unit in excess of a predetermined threshold.

In another aspect, the disclosure provides a method of operating a seeding machine having a row unit operable to plant seeds into soil, the method comprising operating the row unit so that a furrow opener opens a furrow in the soil, a gauge wheel rolls atop the soil, a seed dispenser dispenses seeds into the furrow, and a furrow closer closes the furrow, pushing the row unit frame toward the soil with a row unit downforce actuator to adjustably control soil engagement forces for the furrow opener, the gauge wheel, and the furrow closer, and detecting accelerations of the row unit with an acceleration sensor. A controller in communication with the acceleration sensor and the row unit downforce actuator, executes an algorithm to maintain a target downforce value during operation of the row unit, with an instruction to abandon the target downforce value and relieve the row unit downforce actuator to transition to a floating state that enables the row unit to float over soil obstructions in response to a signal from the acceleration sensor indicative of acceleration of the row unit in excess of a predetermined threshold.

Before embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the accompanying drawings. The disclosure is capable of supporting other embodiments and of being practiced or of being carried out in various ways.

<FIG> illustrates a seeding machine <NUM> (e.g., a row crop planter). The seeding machine <NUM> includes a main frame <NUM>. A plurality of individual row units <NUM> are coupled (e.g., mounted) on a rear portion of the main frame <NUM>, such that the row units <NUM> are pulled over or across a layer of soil <NUM>. Alternatively, the row units <NUM> may be positioned forward of the frame <NUM> and pushed over or across the soil layer <NUM>, or the machine may have a combination of push and pull row units <NUM>. Seed sources, such as storage tanks 22a-22c, are coupled to the main frame <NUM> and hold seed that is delivered, e.g., pneumatically or in any other suitable manner, to a mini-hopper (not shown) associated with each row unit <NUM>. The storage tanks 22a-22c are coupled to the mini-hoppers by way of conduits <NUM>, such as hoses, and a pressurized delivery apparatus (not shown). Each storage tank 22a-22c contains the same or different varieties of seed to be planted in the soil <NUM>. Each row unit <NUM> is connected to a conduit <NUM> such that each row unit <NUM> is coupled to a storage tank 22a-22c to receive seed. As illustrated by way of example only in <FIG>, each row unit <NUM> further includes its own sub-frame <NUM>, to which various components (e.g., a furrow opener, a furrow closer, etc.) are mounted.

<FIG> illustrates an example of a row unit <NUM> that may be used in place of any one or more of the row units <NUM> in <FIG>. Similar to the row unit <NUM>, the row unit <NUM> is also coupled to the main frame <NUM>. In some constructions, a plurality of row units <NUM> are coupled to the main frame <NUM>, similar to the row units <NUM> in <FIG>. As illustrated in <FIG>, each row unit <NUM> includes hoppers 122a, 122b, which hold chemical and seed, respectively (as opposed to the row unit <NUM> receiving seed from bulk storage as in the construction illustrated in <FIG>). The hoppers 122a, 122b are coupled to a row unit sub-frame <NUM>. Each row unit <NUM> also includes a gauge wheel or wheels <NUM> coupled to the row unit sub-frame <NUM>. The gauge wheel <NUM> contacts and rolls along the soil <NUM>, and a furrow opener <NUM> (e.g., an opening wheel or blade or other structure having a stationary or rotating surface that contacts and moves soil away to form a furrow) is coupled to the row unit sub-frame <NUM> for forming a furrow <NUM> (illustrated schematically) in the soil <NUM>. A seed metering device <NUM> coupled to the row unit sub-frame <NUM> receives seeds from the hopper 122b and meters and dispenses the seeds into the furrow <NUM>. A furrow closer <NUM> (e.g., a closing and packing wheel or wheels or other structure having a stationary or rotating surface that contacts and presses soil <NUM>) coupled to the row unit sub-frame <NUM> pushes soil around the seeds to close the furrow <NUM> (see <FIG>). Each row unit <NUM> may also include a seed firmer <NUM> (e.g., an angled arm as illustrated in <FIG>, a press wheel coupled to a press wheel arm, or other structure that firms a seed) coupled to the row unit sub-frame <NUM> that firms each seed and pushes it into the open furrow <NUM> to ensure good seed to soil contact before the furrow <NUM> is closed. The illustrated seed firmer <NUM> is supported on the sub-frame <NUM> by a linkage <NUM>, in particular a parallelogram linkage. <FIG> also illustrates an optional coulter wheel <NUM> and row cleaner <NUM> forward of the furrow opener <NUM>.

The row unit <NUM> also includes a downforce adjustment mechanism <NUM> coupled to the main frame <NUM> and to the row unit sub-frame <NUM>. The downforce adjustment mechanism <NUM> includes springs, pneumatics, hydraulics, linkages, and/or other structures forming an actuator such that when the downforce adjustment mechanism is activated, the downforce adjustment mechanism <NUM> pushes the row unit sub-frame <NUM> of the row unit <NUM> and consequently the furrow opener <NUM> into the soil <NUM> to dig the furrow <NUM>. The gauge wheels <NUM>, however, continue to ride along the top surface <NUM> of the soil <NUM>. A depth <NUM> of the furrow <NUM> is measured from a top surface <NUM> of the soil <NUM> to the bottom <NUM> of the furrow <NUM>, along a direction that is perpendicular to the top surface <NUM> (assuming a flat, non-inclined top surface <NUM>), and therefore depends on a position of the gauge wheels <NUM> relative to the furrow opener <NUM>. In some constructions, the depth <NUM> is equivalent to a distance between a bottom of the gauge wheel or wheels <NUM> and a bottom of the furrow opener <NUM>. The downforce adjustment mechanism <NUM> is mounted on a coupling assembly <NUM> that couples the row unit <NUM> to the main frame <NUM>. In the example shown in <FIG>, a rod of the actuator forming the downforce adjustment mechanism <NUM> is coupled to a link of a parallel linkage <NUM> and is used to exert downward force on the row unit <NUM> through the parallel linkage <NUM>.

<FIG> illustrates an exemplary control circuit for the downforce adjustment mechanism <NUM>, which includes a hydraulic actuator (e.g., double-acting cylinder) as shown. Two control lines 32A, 32B from the actuator are in selective communication with a fluid reservoir <NUM> and an outlet of a pump <NUM> through a multi-position control valve <NUM>. The reservoir <NUM> holds a quantity of fluid at a relatively low pressure (e.g., ambient), or so-called "tank" pressure, while the pump outlet provides a relatively higher fluid pressure source such (e.g., supplied from the reservoir <NUM>) that can be applied to one of the control lines 32A, 32B for applying force to a particular side of the hydraulic actuator of the downforce adjustment mechanism <NUM>. A pressure control valve <NUM> is positioned along the first control line 32A between the control valve <NUM> and the hydraulic actuator. The control valve <NUM> can be a spool valve having a plurality of ports on each side, connectable through various connection passages in accordance with a position of the control valve <NUM>. In the illustrated construction, the control valve <NUM> has four positions, which are labeled in the legend according to a left-to-right convention of the drawing. In the first position, the control valve <NUM> is closed and there are no fluid connections of the components on the respective sides of the control valve <NUM>. In the second position, the two control lines 32A, 32B are coupled to each other to define a "float" position of the downforce adjustment mechanism <NUM>, as neither end of the hydraulic actuator of the downforce adjustment mechanism <NUM> is supplied with pressurized fluid from the pump <NUM> or connected for draining to tank pressure at the reservoir <NUM>. The third position of the control valve <NUM> is an extend position, whereby the first control line 32A is coupled to the outlet of the pump <NUM> and the second control line 32B is coupled to the reservoir <NUM>. In the third position of the control valve <NUM>, the downforce adjustment mechanism <NUM> can increase downforce. The fourth position of the control valve <NUM> is a retract position, whereby the second control line 32B is coupled to the outlet of the pump <NUM> and the first control line 32A is coupled to the reservoir <NUM>. In the fourth position of the control valve <NUM>, the downforce adjustment mechanism <NUM> can decrease downforce.

In addition to the downforce adjustment mechanism <NUM>, which acts as a main downforce actuator on the entire sub-frame <NUM> and all ground-engaging implements depending therefrom, the row unit <NUM> can further include one or more separate downforce adjustment mechanisms <NUM>, <NUM>. For example, a first additional downforce adjustment mechanism <NUM> can be operably coupled to the row cleaner <NUM>. Alternatively or additionally, an additional downforce adjustment mechanism <NUM> can be operably coupled to the furrow closer <NUM>. Each of the downforce adjustment mechanisms <NUM>, <NUM> includes springs, pneumatics, hydraulics, linkages, and/or other structures forming an actuator such that when the downforce adjustment mechanism is activated, it pushes downward to press the implement (i.e., the row cleaner <NUM> or the furrow closer <NUM>) against the soil <NUM> with increased force. In some constructions, the downforce adjustment mechanisms <NUM>, <NUM> change the effective height of the respective implement with respect to the sub-frame <NUM> and/or with respect to the gauge wheels <NUM>. Either or both of the downforce adjustment mechanisms <NUM>, <NUM> can be provided as part of a system or control circuit similar to that of <FIG>, having operational control provided by a control valve like the control valve <NUM> described above, among others.

With continued reference to <FIG>, the gauge wheel(s) <NUM> are coupled to the sub-frame <NUM> with respective arms <NUM> and respective pivots <NUM>. Stops <NUM> are also provided for each gauge wheel arm <NUM> to limit the upward rotation of each gauge wheel arm <NUM>. The stops <NUM> are adjustable to a desired position to set the depth <NUM> of the furrow <NUM>. The position of the stops <NUM> may be manually adjusted, or a remote adjustment assembly may be included such as shown in <CIT>.

The row unit <NUM> also includes at least one acceleration sensor <NUM> operable to sense accelerations of the row unit <NUM>, (e.g., from external ground forces on the row unit <NUM>). The illustrated acceleration sensor <NUM> is supported directly or indirectly by the sub-frame <NUM>. Two different locations for the acceleration sensor <NUM> are shown in <FIG>, but they are examples only. In one example, the acceleration sensor <NUM> is disposed on the sub-frame <NUM>, while in another example it can be disposed on the gauge wheel arm <NUM> or on one or more of the gauge wheels <NUM> themselves. In some constructions, more than one row-based acceleration sensor <NUM> is provided on the row unit <NUM>. These are examples only.

The acceleration sensor <NUM> can take a wide variety of different forms. For instance, it can be an accelerometer that directly generates a signal indicative of acceleration. The acceleration sensor <NUM> can also be a pressure sensor disposed to sense the pressure changes in the downforce adjustment mechanism <NUM> (e.g., within a hydraulic actuator and/or hydraulic circuit coupled to the hydraulic actuator, or within a pneumatic actuator and/or pneumatic circuit coupled to the pneumatic actuator). As accelerations are imparted to the row unit <NUM>, they can be reflected in pressure changes in the downforce adjustment mechanism <NUM>. The acceleration sensor <NUM> can also be a location sensor that generates a signal indicative of its geographic location or position. As that position changes over time, the acceleration can be derived from the position signal and from a signal indicative of a time or rate of change in that position. Thus, if the acceleration sensor <NUM> is a position sensor located on the gauge wheel <NUM>, the rate of change in position over time, per unit of time, yields an indication of acceleration of the gauge wheel <NUM>. The acceleration sensor <NUM> can be another type of sensor as well.

As illustrated in <FIG>, in some constructions signals from at least one acceleration sensor <NUM> are sent to a controller <NUM>, which interprets or calculates an acceleration value. In some constructions a display <NUM> is also provided (e.g., in the operator cab), which displays (e.g., in real time) the acceleration data or data inherently related thereto. The controller <NUM> may be positioned at various locations on seeding machine <NUM>. For example, in some constructions the controller <NUM> is positioned within the operator cab, and signals are sent by wire or wirelessly from the acceleration sensor or sensors <NUM> to the controller <NUM>. In some constructions the acceleration sensor or sensors <NUM> themselves includes a controller <NUM>. Other constructions include different locations for the controller <NUM>.

The controller <NUM> (which may include a memory and a processor for receiving and sending signals and performing calculations) uses the received signals to activate and control movement of the downforce adjustment mechanism <NUM> and to thus control an overall downforce applied to the row unit <NUM>. In some constructions, the controller <NUM>, with data from the acceleration sensor or sensors <NUM>, increases row unit downforce from the downforce adjustment mechanism <NUM> as travel speed of the seeding machine <NUM> increases. This can be done with or without reliance on actual speed data (e.g., from a travel speed sensor <NUM> of the row unit <NUM> or the seeding machine at large). For example, actual acceleration measurements give an indication of travel speed, and may even be a more beneficial parameter on which to base row unit downforce adjustment, as the typical result of increased travel speed is increased bounce or harshness of the row unit <NUM> with respect to the ground. A contributor to this phenomenon is that hydraulics in the downforce adjustment mechanism <NUM> present enhanced rigidity and a general inability to absorb impacts (e.g., rock strikes, etc.) to the row unit <NUM>. Although there are benefits to simply increasing downforce in response to higher seeding machine travel speed (and this may be a function of the control method carried out by the controller <NUM>) the acceleration sensor or sensors <NUM> allow more advanced control of the downforce adjustment mechanism <NUM> during operation of the seeding machine <NUM>. For example, the signals from the acceleration sensor or sensors <NUM> can be used to identify the onset of an impact event to the row unit <NUM>, whereby the controller <NUM> responds to quickly relieve downforce in the downforce adjustment mechanism <NUM>.

With reference to <FIG>, from the start of operation of the seed machine <NUM>, the travel speed sensor <NUM> measures travel speed of the seed machine <NUM> and reports the travel speed signal to the controller <NUM>. Meanwhile, for example (and simultaneously with step <NUM>), the acceleration sensor or sensors <NUM> generates signals (e.g., based on measured acceleration) at step <NUM>, and corresponding acceleration signals are sent to the controller <NUM>, which at step <NUM> receives the signals. With reference to the center column of <FIG>, the method continues with step <NUM> in which an algorithm of the controller <NUM> is used for determining row unit downforce (e.g., a target downforce value). The target downforce value can be calculated by the controller <NUM> based on one or both of the signals from steps <NUM> and <NUM>. From the algorithm, the controller <NUM> generates an input for the downforce system having the adjustment mechanism <NUM> at step <NUM>, and this effects a downforce adjustment at step <NUM>. This downforce control algorithm can be programmed to calculate the appropriate target downforce value (e.g., based on various soil conditions, travel speed, etc.), but may also be manually overridden with a specific command from an operator. The algorithm can be programmed to measure resultant downforce, for example at the downforce adjustment mechanism <NUM> or elsewhere on the row unit <NUM>, and to continuously make adjustments to the downforce as needed (e.g., creating a closed loop). It should also be appreciated that the target downforce value can be a range of values defining a control band in which downforce is to be maintained. The input of step <NUM> can be an input to the control valve <NUM> of <FIG>, which in turn effects the downforce actuator adjustment of step <NUM>. The controller <NUM> may also provide an input to the pump <NUM>, controlling an operation and/or output thereof.

As discussed above, the downforce control algorithm is further programmed with a feature to abandon the target downforce value and relieve the actuator provided by the downforce adjustment mechanism <NUM> in response to a signal from the acceleration sensor or sensors <NUM> indicative of acceleration of the row unit <NUM> in excess of a predetermined threshold. For example, the controller <NUM> can be programmed to momentarily pause the normal downforce control algorithm (e.g., for a predetermined amount of time, or for an indeterminate amount of time that is dependent upon the acceleration observed-the value and/or duration thereof) before automatically resuming. Abandoning the target downforce value effectively transitions the downforce adjustment mechanism <NUM> and the row unit as a whole from a rigid active-downforce state into a deactivated or semi-deactivated impact-absorbing mode or "float" mode in which the downforce is allowed to drop below the target downforce value. This allows the row unit <NUM> to absorb the impact and float over a ground obstruction rather that receiving the impact directly and suffering the potential consequences, such as erratic bounce and/or structural damage. The float mode can include a partial or full relief of pressure in the downforce adjustment mechanism <NUM> timed to coincide with the engagement with the obstruction as identified by the acceleration sensor or sensors <NUM>. The transition to the float mode can be accomplished in some constructions by putting the control valve <NUM> into the second position so that the actuator of the downforce adjustment mechanism <NUM> is positively in the float setting in which its two sides (i.e., extension and retraction sides) are coupled to each other. In other constructions, float mode can include a programmed execution of a downforce reduction strategy that drops downforce below the target downforce value. Such a downforce reduction strategy can reduce downforce by a predetermined amount of force, or by a predetermined ratio or percentage of the target downforce value. However, the downforce reduction strategy should not be confused with setting a new target downforce value, since it is not based on planting performance metrics, but rather the occurrence of the of the row unit acceleration in excess of the threshold. The method of downforce control is not exclusive and may incorporate one or more additional features or functions, such as monitoring furrow depth, controlling forward travel speed of the seeding machine <NUM>, and evaluating soil moisture content to determine downforce and/or depth targets, among others.

As noted in <FIG>, there are additional aspects of the row unit <NUM> and operating methods thereof, each of which can be carried out alone or in combination with other aspect(s) disclosed herein in a particular row unit construction. For example, along the left side of <FIG> an active row cleaner engagement routine is disclosed, and along the right side of <FIG> an active furrow closer engagement routine is disclosed, and these are described below in respective order. Beginning at step <NUM>, an algorithm programmed to the controller <NUM> operates to determine desired soil engagement of the row cleaner <NUM>. This, like the algorithm for row unit downforce, can be carried out on the basis of information from one or both of the steps <NUM>, <NUM> in which travel speed and/or acceleration are reported to the controller <NUM>. That is to say the algorithm may determine an engagement setting for the row cleaner <NUM> (in terms of downforce or relative height) that is based on travel speed, based on acceleration, or based on a combination of travel speed and acceleration. From the algorithm, the controller <NUM> generates an input for the row cleaner downforce adjustment mechanism <NUM> at step <NUM>, and this effects an adjustment at step <NUM>. Like the primary downforce control algorithm, the setting for the row cleaner <NUM> may also be able to be manually overridden with a specific command from an operator. The algorithm can be programmed to measure resultant downforce at the row cleaner, for example at the row cleaner downforce adjustment mechanism <NUM> or elsewhere on the row cleaner <NUM>, and to continuously make adjustments to the row cleaner downforce as needed (e.g., creating a closed loop). The active row cleaner engagement control, however, can also be operated as an open loop control. The row cleaner engagement control can specifically be programmed to reduce the soil engagement setting in response to an increase in travel speed (and likewise increase the soil engagement setting in response to a decrease in travel speed), as the row cleaner <NUM> may gain effectiveness with increased speed. This is one example of a relationship between speed and adjustment of row cleaner engagement setting, which may apply for many soil conditions. However, alternate soil conditions may dictate that the controller <NUM> be programmed to increase the soil engagement setting for the row cleaner <NUM> in response to increased travel speed to maintain the desired efficacy of the row cleaner <NUM>. The row cleaner engagement control provides an implement-specific downforce control method, which is still subject to the overall row unit downforce control method. In other words, the active control of the row cleaner downforce adjustment mechanism <NUM> can operate to vary the proportion of total row unit downforce borne by the row cleaner <NUM> during operation in order to maintain a value at a desired amount or within a desired range.

Claim 1:
A row unit (<NUM>, <NUM>) for a seeding machine (<NUM>) operable to plant seeds into soil (<NUM>), the row unit (<NUM>, <NUM>) comprising:
a frame (<NUM>) supporting a furrow opener (<NUM>) for opening a furrow (<NUM>) in the soil (<NUM>), a gauge wheel (<NUM>) for rolling atop the soil (<NUM>), a seed dispenser (<NUM>) for dispensing seeds into the furrow (<NUM>), and a furrow closer (<NUM>) for closing the furrow (<NUM>);
a row unit downforce actuator (<NUM>) operable to push the row unit frame (<NUM>) toward the soil (<NUM>) to adjustably control soil engagement forces for the furrow opener (<NUM>), the gauge wheel (<NUM>), and the furrow closer (<NUM>);
an acceleration sensor (<NUM>) configured to detect accelerations of the row unit (<NUM>, <NUM>); and
a controller (<NUM>) in communication with the acceleration sensor (<NUM>) and the row unit downforce actuator (<NUM>),
the controller (<NUM>) programmed with an algorithm to maintain a target downforce value during operation of the row unit (<NUM>, <NUM>),
wherein the controller (<NUM>) is further programmed to abandon the target downforce value and relieve the row unit downforce actuator (<NUM>) to transition to a floating state that enables the row unit (<NUM>, <NUM>) to float over soil obstructions in response to a signal from the acceleration sensor (<NUM>) indicative of acceleration of the row unit (<NUM>, <NUM>) in excess of a predetermined threshold.