Abstract:
A fill tube and sensor assembly has a single electronic sensor to detect the level of product in a hopper of an agricultural implement relative to a fill line. The electronic sensor can be positioned at various heights relative to the fill tube to provide variability in the height of the fill line. The sensor provides a full level signal until product is drawn from the fill tube. Once the product is dispensed from the fill tube and into the general interior volume of the hopper, the single sensor provides an empty level signal that can be used to alert an operator of a diminished product supply or control operation of the farm implement.

Description:
FIELD OF THE INVENTION 
   The present invention relates generally to agricultural implements, and in particular, to a product fill level sensor apparatus operative to detect the level of product in a product container or hopper of an agricultural implement. 
   BACKGROUND OF THE INVENTION 
   Seed and fertilizer planting farm implements typically have a seed and/or fertilizer storage container that is mounted to the farm implement. As the farm implement is traversed across a field, a product metering assembly dispenses product from the container along a seedbed in a metered fashion. 
   Generally, it is desirable to provide a product fill status to an operator regarding the fill level of product in the container. Typically, two separate sensors will be associated with the container. One sensor is mounted near the inlet of the container and the other sensor is mounted near the outlet of the container. The inlet sensor is used to determine when the container is full of product and the outlet sensor is used to determine when the container is empty of product. In this regard, conventional fill level detection systems have relied upon two separate sensors to provide separate full and empty signals. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to a fill tube and sensor assembly in which a single electronic sensor, rather than two or more sensors, is used to detect the level of product in a hopper of an agricultural implement relative to a variable fill line. The sensor assembly includes an electronic sensor that can be positioned at various heights relative to the fill tube to provide variability in the height of the fill line. The fill tube is designed to be filled in a manner that is similar to the filling of the hopper as a whole, but product is not dispensed from the fill tube until the level of product in the hopper is lower than the discharge end of the fill tube. In this regard, a single sensor provides a full level signal until product is drawn from the fill tube. Once the product is dispensed from the fill tube and into the general interior volume of the hopper, the single sensor provides an empty level signal that can be used to alert an operator of a diminished product supply or control operation of the farm implement accordingly. 
   Therefore, in one aspect of the invention, a bin for use with an agricultural implement and configured to contain agricultural product that is to be selectively withdrawn as the agricultural implement traverse a field is disclosed. The bin includes a container having a first opening that allows product to be deposited into the container and a second opening that allows product to be withdrawn in a metered fashion from the container. A single electronic sensor provides a first signal when product within the container is above a predefined fill level and provides a second signal when product within the container is below the predefined fill level. 
   In accordance with another aspect, the present invention is directed to a farm implement that includes a feed tube for delivering product to a seedbed. A product container is operably associated with the feed tube and adapted to hold product to be dispensed through the feed tube. The farm implement includes a measuring gauge disposed in the product container at a height such that product does not fill the measuring gauge unless a product level in the product container exceeds the height. The farm implement further includes a sensor associated with the measuring gauge that outputs either a first signal indicating that product in the product container is above a predefined fill level or a second signal indicating that product in the product container is below the predefined fill level, wherein the predefined fill level is lower than the height. 
   According to yet a further aspect of the invention, a product container for use with a farm implement designed to dispense product is disclosed. The product container includes a hopper and a fill tube designed to be mounted to an interior wall of the hopper. The product container further includes a single sensor associated with the fill tube and adapted to provide a first signal when product in the fill tube is above a variable fill level and provide a second signal when product in the fill tube is below the variable fill level. 
   Other objects, features, and advantages of the invention will become apparent to those skilled in the art from the following detailed description and accompanying drawings. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred exemplary embodiments of the invention are illustrated in the accompanying drawings in which like reference numerals represent like parts throughout. 
     In the drawings: 
       FIG. 1  is a schematic perspective view of a seed planting assembly supporting a plurality of seed planting units constructed in accordance with a preferred embodiment of the invention; 
       FIG. 2  is a side elevation view of a seed planting unit illustrated in  FIG. 1  with a center drain fill tube and sensor assembly; 
       FIG. 3  is a partial isometric view of a fill tube and sensor assembly for use with the seed planting unit shown in  FIG. 2 ; 
       FIG. 4  is a sectional view of the fill tube and sensor assembly of  FIG. 3  taken along line  4 - 4  of  FIG. 3 ; 
       FIG. 5  is a block diagram representation of an electronic fill level sensor incorporated into the sensor assembly shown in  FIGS. 3-4 ; 
       FIG. 6A  is a sectional view of the fill tube and sensor assembly taken along line  6 A- 6 A of  FIG. 4  with the level of product in the fill tube below a given fill line; 
       FIG. 6B  is a sectional view of the fill tube and sensor assembly taken along line  6 B- 6 B of  FIG. 4  with the level of product in the fill tube above the given fill line; and 
       FIG. 7  is a partial side elevation view of a product bin having an edge drain fill tube and sensory assembly according to another aspect of the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIG. 1 , a seed planting assembly  10  includes a laterally extending toolbar  12  connected at its middle (or other location) to a forwardly extending tow bar  14 . Tow bar  14  includes a connector  16  disposed at its longitudinally forward end and configured to mate with a corresponding hitch, or the like, of a towing tractor (not shown). Toolbar  12  is supported by a chassis  18  that is connected to tow bar  14  via a hinged bracket assembly  20 . Chassis  18  is supported on the ground by two pair of wheels  22 . Outer portions of tool bar  12  are supported by outer wheels  24  having an adjustable height to thus control the height of the toolbar  12 . 
   A plurality of seed planting units (or row units)  26  extends longitudinally rearwardly from toolbar  12 . In particular, referring also to  FIG. 2 , each planting unit  26  includes a frame  28  that is connected at its front end  30  to toolbar  12  via a mounting assembly  32 . Mounting assembly  32  includes a pair of upper support beams  34  (one illustrated) and a pair of lower support beams  36  (one illustrated) that are hingedly connected to frame or drill  28  at one end, and to a mounting structure  38  at another end. Mounting structure  38  is, in turn, connected to tool bar  12 . 
   Frame  28  defines a front end  30  having a first pair of aligned apertures (not numbered) extending laterally therethrough. Corresponding apertures (not numbered) extend through the rearward ends  40  of each upper support beam  34 . A pin  42  extends through each pair of aligned apertures, and is fastened to provide a joint  44  that enables planting unit  26  to pivot about mounting assembly  32 . 
   Likewise, the front end  30  of frame  28  defines a second pair of laterally extending apertures (not shown) disposed below the first pair of apertures. The second pair of apertures is laterally aligned with corresponding apertures (not shown) extending laterally through the rearward ends  46  of each lower support beam  36 . A pin  48  extends through each pair of aligned apertures and is fastened to provide a joint  50  that enables planting unit  26  to pivot about mounting assembly  32 . 
   Each upper support beam  34  further defines a forward end  52  that defines corresponding apertures (not shown) extending laterally therethrough. Likewise, each lower support beam  36  defines a forward end  54  that defines apertures (not shown) extending laterally therethrough. Mounting structure  38  extends rearwardly from tool bar  12 , and defines laterally extending apertures (not shown) that are aligned with the apertures extending through forward ends  52  and  54 . Upper and lower pins  56  and  58  extend through the corresponding apertures and form corresponding joints  60  and  62  that pivotally connect the forward ends  52  and  54  of support beams  34  and  36  to mounting structure  38 . 
   It should thus be appreciated that while the right-hand side of mounting assembly  32  (taken with respect to a view from rear-to-forward) is illustrated as being mounted onto the right-hand laterally outer walls of frame  28 , the left-hand side of mounting assembly  32  is likewise mounted onto the left-hand laterally outer walls of frame  28  in a symmetrical and parallel manner with respect to the right-hand side of the mounting assembly. Accordingly, while the left support beams  34  and  36  are connected to the left side of planting unit  26  and mounting structure  38  such that both pairs of beams  34  and  36  are parallel to each other during operation. 
   As is well-known in the art, planting units  26  are mounted in a side-by-side (lateral) relation relative to each other along the toolbar  12 . While sixteen such row units are illustrated in  FIG. 1 , the present invention contemplates that more or less than sixteen row units can be assembled on a single toolbar  12 . During operation, forward movement of the tractor causes row units  26  to ride along the ground, forming a plurality of seed trenches into which product, such as seeds, is dispensed and are subsequently closed. 
   Referring again to  FIG. 2 , each planting unit  26  preferably includes a conventional seed trench opening assembly  64 , each of which including a pair of laterally spaced seed trench opener discs  66  (also referred to as reels or coulters) that converge forwardly and downwardly to define a convergence point  68 . A seed trench firming point  70  is disposed rearwardly from convergence point  68 , and an opener shoe  72  is disposed rearwardly from seed trench firming point  70 . Firming point  70  preferably extends slightly downwardly from the opener shoe  72 , and firms the seed trench that is formed by convergence point  68 . Firming point  70  and opener shoe  72  are preferably integrally connected. The depth of the seed trench can be controlled by a pair of gauge wheels (not shown) that are supported by gauge wheel arms  74  as understood by those having ordinary skill in the art. Alternatively, the planting unit  26  can be provided with a runner opener type for providing a seed trench in the ground as is appreciated by one having ordinary skill in the art. Planting unit  26  further includes a pair of seed trench closer discs  76  disposed rearwardly from opener shoe  72 . A press wheel  78  is disposed rearwardly from closure discs  76 . 
   A pair of screw and spring assemblies  80  (one shown) is displaced laterally from each other and extends downwardly from a first support member (not shown) extending laterally between the upper support beams  34  to a second support member (not shown) extending laterally between the lower support beams  36 . Assemblies  80  are angled with respect to support beams  34  and  36 , and can thus be actuated in a known manner to increase and decrease the down pressure exerted onto seed trench opening assembly  64  to control downward force on the opening discs  66 , as is well understood by those having ordinary skill in the art. A knob  82  extends rearwardly from frame  28 , and can be rotated to adjust the depth of gauge wheels (not shown) which control the desired seed trench depth as appreciated by one having ordinary skill in the art. 
   Planting unit  26  further includes a seed hopper  84  that provides storage for seed material that is to be gravitationally deposited into the seed trench that is formed as the seed trench opening assembly  64  moves across the field during operation. It should be appreciated, however, that a hopper container, smaller than container  84 , can alternatively be connected to a centralized bin or large hopper in a conventional manner. In the illustrated embodiment, seeds are delivered from seed hopper  84  to a seed metering assembly  86  that acts under vacuum received by connector  88 . The received seeds are then delivered into a seed tube  90  at a uniform rate. Seed tube  90  defines a conduit having an outlet end immediately downstream of firming point  70  and upstream of seed trench closer discs  76 . Seed tube  90  thus receives seeds from metering assembly  86  and defines a substantially vertical passage through which the seeds are delivered through the opener shoe  72  and into the seed trench. The components of seed metering assembly  86  are further described in U.S. Pat. No. 6,109,193, the disclosure of which is hereby incorporated by reference. In a similar manner, seed hopper  84  may also be used to deposit fertilizer to the seed bed. Alternately, a separate hopper (not shown) containing fertilizer may be used. 
   During operation, as the tractor pulls the tool bar  12  across and over the ground, the seed trench opening assembly  64  opens a seed trench in the ground. Seeds from the hopper  84  flow into the seed metering assembly  86  in bulk and are subsequently deposited into the seed trench via seed delivery tube  90  at a controlled rate. The seed trench closer discs  76  trail the seed trench opening assembly  64  and, as the seed planting unit  26  is drawn across the field, close the seed trench together and over the seed dispensed by the seed metering assembly  86 . The trailing press wheel  78  compacts the soil closed over the delivered seeds. 
   Planting unit  26  can also be equipped with a pesticide hopper  92  that is mounted towards a rear end of the planting unit. Hopper  92  preferably includes an insecticide and is provided with conventional dispensing apparatus for applying controlled amounts of insecticide where desired in combination with the planting of seeds by each planting unit  26 . 
   Referring again to  FIG. 1 , each planting unit  26  can be coupled to an air moving system  94  that includes one or more air moving units (collectively identified as  96 ). While air mover unit(s)  96  is configured to provide negative pressure, they can alternatively function as blower units if a positive pressure seed metering assembly is implemented in planting units  26 . Air moving system  94  includes a lower lateral tubing member  98  that is connected at its middle to one of the air moving units  96 , and extends laterally outwardly therefrom in both directions. A plurality of openings (not shown) are formed in tubing member  98  that connect to a forward end of a corresponding plurality of flexible intake tubes that, in turn, connect with the corresponding metering assembly connector  88 . 
   A bifurcated arrangement is illustrated with respect to a pair of upper lateral tubing members  100  that are connected at their laterally inner ends to one or more air mover units  96 . Tubing members  100  extend parallel to, and are disposed above, tubing member  98 , and are connected at their outer ends to outer tubing members  102 . Outer tubing members  102  are vertically aligned with lower tubing member  98 , and extend across those planting units  26  that are disposed laterally outwardly with respect to lower tubing member  98 . A plurality of openings (not shown) are formed in tubing members  102  that connect to a plurality of flexible intake tubes that, in turn, connect with the corresponding metering assembly connectors  88  of laterally outwardly disposed planting units  26 . 
   During operation, air moving units  96  draw air through the metering assemblies  86  of all planting units  26  to which the lateral tubes  98  and  102  are operably connected. The number of air mover units  96  implemented in a given seed planting assembly depends largely on the number of planting units  26  and the airflow rating of each air mover unit. 
   The present invention recognizes that certain seed types (for example, soybeans) are well suited to be planted in seed trenches that are laterally spaced a distance equal to the distance between adjacent seed trench opening assemblies  64  of all planting units  26  disposed on tool bar  12 . However, in order to accommodate other seed types (for example, corn) that require additional distance between adjacent seed trenches in order to grow properly, it is necessary, from time to time, to raise certain planting units  26  above the ground  104 . 
   It should thus be appreciated that the term “raised position” as used in the present application refers to a position whereby planting unit  26  has been translated upwardly to a height sufficient to cause at least the corresponding seed trench opening assembly  64  (and preferably closer disc  76  and press wheel  78 ) to become suspended above the ground  104 . Accordingly, raised planting units  26  will not form a seed trench in the ground  104  when the seed planting assembly  10  is driven across the ground  104 . In one preferred embodiment, alternating planting units can be raised from the ground  104 , thereby doubling the distance between adjacent seed trenches compared to the distance that is achieved when all planting units are engaged, such as described in U.S. Pat. No. 7,111,566, the disclosure of which is incorporated herein. Additionally, each planting unit  26  may include a vertical positioner assembly and associated linkages such as described in U.S. Pat. No. 7,111,566 to raise and lower the planting unit. 
   Referring again to  FIG. 2  and further reference to  FIG. 3 , hopper  84  includes a center drain fill tube  106  adapted to provide product fill level information. More particularly, the fill tube  106  is designed to be mounted to an interior wall  108  of the hopper  84  and includes a single electronic sensor assembly  110  that monitors the level of product within the hopper  84  relative to a single fill level. Alternately, the fill tube  106  may be integrally formed with wall  108 . When the product in the fill tube  106  is above the fill level, a suitable signal is provided and, conversely, when product in the fill tube  106  is below the fill level, a suitable signal is provided. In a preferred embodiment, the height of the electronic sensor assembly  110  is set such that when product falls below the fill level, an operator will know that it is time to refill the hopper  84  or be able to assess how much product is available for dispensing until the hopper  84  becomes empty. 
   The fill tube  106  has a generally cylindrical shaped housing  112  providing an open fill (inlet) end  114  and an open discharge (outlet) end  116 . In one embodiment, the open discharge end  116  is slightly angled toward the interior of the hopper  84 . Thus, when product is loaded into the hopper  84 , product will also be loaded into the fill tube  106 . As product is dispensed from the bottom of the hopper  84 , the level of product within the hopper  84  will decrease. More particularly, as product is dispensed, the volume in the hopper  84  previously occupied by the dispensed product will be filled as product falls by gravity from higher levels in the hopper  84 . When the level of product in the hopper  84  falls below the discharge end  116 , the level of product in the fill tube  106  will be drawn down. When the level of product in the fill tube  106  falls below a defined fill level, the fill level sensor assembly  110  provides an output signal that can be used to signal the operator that the fill level in the hopper  84  is below that fill level, e.g. empty. For example, the output signal can be used to illuminate an indicator light (not shown) in the operator cab of the farm implement  10 , sound an audible alarm, or both. 
   In this regard, as product drains from the center of the hopper  84  first, the larger body of product material is generally undisturbed within the hopper. As the fill level in the hopper  84  approaches empty, there may be some drawdown of product within the fill tube  106 . As the product level in the hopper  84  further approaches empty, a gap will eventually occur between the discharge end of the fill tube  106  and the fill level within the hopper  84 . As the level of product in the fill tube  106  is higher than that in the hopper  84 , product will drain relatively quickly from the fill tube  106 . Once the product level in the tube  106  drops below the fill level, a corresponding signal is provided. In this regard, the fill tube  106  has a cross-sectional area of the fill tube  106  is large enough to allow product to pass freely once the product level in the hopper  84  drops below the discharge end of the fill tube  106 . 
   Referring now to  FIG. 3 , a vertically oriented slot  118  is formed in the housing  112  and defines a path along which the electronic sensory assembly  110  may be variably positioned. Thus, in one embodiment, an operator may position the electronic sensor assembly  110  at a desired height relative to the fill tube housing  112  by incrementing the electronic sensor assembly  110  within the slot  118 . 
   The sensor assembly  110  is coupled to a mounting assembly  120  that permits the sensor assembly  110  to be variably positioned within slot  118 . In one embodiment, the mounting assembly  120  includes a series of plates  122  mounted to the interior surface of the housing  112  and designed to bypass one another as the sensor assembly  110  is repositioned within the slot  118 . The plates  122  are mounted to the interior surface of the housing  112  in a manner that allows the sensor assembly  110  to be positioned at various elevations along the slot  118  without requiring a separate locking or similar device to secure the sensor assembly  110  at a given elevation. Moreover, the plates  11  and the sensor assembly  110  collectively keep the slot  118  closed regardless of the position of the sensor assembly  110 . As such, product is kept from falling out of the fill tube housing  112  through the slot  118 . 
   The sensor assembly  110  includes a sensory circuitry ( FIG. 5 ) contained within a sensor housing  124 , that as shown in  FIG. 4 , extends partially into the interior of the fill tube  106 . The sensor housing  124  is coupled to a handle  126  to allow an operator to manually slide the sensor assembly  110  along slot  118  to a desired position. A cable  128  extends from the handle  126  and includes a power lead (not shown) electrically connected to the sensor circuitry to provide power to the sensor circuitry. Additionally, the cable  128  may include control and data wires (not shown) to communicate control commands to the sensor circuitry and readout data. Alternately, wireless communication and data transfer techniques and associated hardware/software could be used for sensor control and data transfer. 
   In one preferred embodiment, and referring now to  FIG. 5 , the sensory circuitry  130  generally includes a transmitter  132  and a receiver  134  both communicatively coupled to a processor  136  or similar control device. With further reference to  FIGS. 6A-6B , under the control of the processor  136 , the transmitter  132  is caused to transmit an infrared signal, for example, within the interior of the fill tube  106  along a fill line  138 . The receiver  134  detects the infrared signal, as reflected by the contents within the fill tube  106 , if any. The processor  136  compares the intensity of the emitted signal to the intensity of the received signal to determine if the level of product in the fill tube  106  is above or below the fill line  138 . 
   For example, the processor  136  may control the transmitter  132  to emit an infrared signal at a given signal strength along the fill line  138 . If the level of product  140  in the fill tube  106  is at or above the fill line, such as in  FIG. 6B , a portion of the infrared signal will be absorbed by the product  140  and not reflected back toward the receiver  134 . Since there is a significant difference in the intensities of the two signals, the processor  136  will output a signal indicating that product  140  in the fill tube  106  and thus the hopper  84  as a whole is above the given fill line  138 . In one embodiment, an indicator lamp  142  proximate the operator cab of the farm implement is suitably activated to indicate that the product level is above the fill line. For instance, the lamp  142  may include a green LED that is energized when the product level is at or above the fill line. 
   On the other hand, if the level of product in the fill tube  106  is below the fill line  138 , such as in  FIG. 6A , then the intensity of the received infrared signal will be similar to that of the emitted infrared signal as the signal will be reflected back by the interior surfaces of the fill tube housing  112 . The processor  136  may provide a suitable “low product level” signal to the lamp  142  or sound an alarm. For instance, the lamp  142  may include a yellow or red LED that is activated in response to the low product level signal. 
   In a preferred embodiment, the sensor is positioned at the discharge end of the tube so that an empty signal is provided when the product is completely drawn from the fill tube; however, it is understood that the sensor could be positioned at other levels, thereby charging the position at which an “empty” signal is provided. 
   Referring now to  FIG. 7 , a portion of a hopper  144  having an edge drain fill tube  146  with a fill level sensor  147  is shown in accordance with an alternate embodiment of the present invention. In this configuration, the discharge wall  148  of the hopper  144  is much steeper than that of the hopper  84  shown in  FIG. 2 . The fill tube  146  is secured to an interior wall  150  of the hopper  144 . In this type of hopper  144 , product moves down in a more even manner across the diameter of the hopper compared to hoppers with a flatter drain wall, such as illustrated in  FIG. 2 . Thus, product will drain from the fill tube  146  in an incremental fashion similar to the incremental drawdown from the hopper  144  as a whole until the level of product level drops below the discharge end of the fill tube. Once that occurs, product will dispense from the fill tube  146  relatively quickly. 
   It is recognized that other types of sensors other than infrared sensors may be used, such as ultrasonic sensors, for example. Additionally, it is recognized that the fill tube could be constructed of multiple linear sections that can be retracted or extended to vary the overall length of the fill tube. It is also contemplated that tubes of different diameters could be used to account for different sized product material. 
   It will be appreciated that the length of the fill tubes described herein may be matched to the depth of the hopper. In this regard, in one embodiment, the length of the fill tube is adjustable so that the same fill tube can be used for deeper as well as shallower hoppers. 
   Many changes and modifications could be made to the invention without departing from the spirit thereof. The scope of these changes will become apparent from the appended claims.