Abstract:
An apparatus for indicating a grain tank fill level for a grain tank ( 20 ) of an agricultural harvester ( 10 ), the harvester ( 10 ) having a chassis ( 12 ), an operator cabin ( 18 ) on the chassis ( 12 ); a threshing, separating, and cleaning means ( 24 ) on the chassis ( 12 ) for processing crop, a grain tank ( 20 ) on the chassis ( 18 ) for storing harvested grain and having an actual fill level of grain, a display ( 48 ) disposed in front of the operator in the direction of travel for displaying a fill level of the grain tank; a calculating means ( 46 ) coupled to the display ( 48 ) for calculating a fill level of the grain tank to be displayed on the display ( 48 ), and an operator input device ( 70 ) coupled to the calculating means ( 46 ) for selecting between first and second modes of operation, wherein the calculating means ( 46 ) is configured to repetitively and automatically calculate the fill level of the grain tank ( 20 ) in a first mode of operation and configured to repetitively and automatically indicate a scaled fill level that is scaled to a reference fill level different from the actual fill level in a second mode of operation, and further wherein the operator input device ( 70 ) is configured to indicate to the calculating means ( 46 ) the reference fill level when the operator input device ( 70 ) is selected by the operator.

Description:
FIELD OF THE INVENTION 
     The invention relates to agricultural equipment. More particularly, it relates to harvesting equipment. Even more particularly it relates to grain tank level indicators for agricultural harvesters. 
     BACKGROUND OF THE INVENTION 
     Agricultural harvesters are configured to receive cut crop from harvesting devices mounted at the front of the agricultural harvester, to thresh, separate, and clean that crop and to store that crop in a reservoir on the agricultural harvester commonly called a grain tank or grain bin. The grain tank or grain bin is typically an open topped structure disposed at the very top of the agricultural harvester. 
     When the grain tank is full, the operator must stop the agricultural harvester and wait until it can be unloaded. It is generally preferred not to stop the agricultural harvester for the unloading process, but to permit the harvester to cut and process crop continuously, unloading the harvester to a secondary vehicle, often called a grain cart (typically pulled by an agricultural tractor) or grain truck as the agricultural harvester moves through the field with the grain cart or truck alongside. 
     To ensure that unloading happens at the appropriate time, the operator of the harvester must regularly and periodically check the level of grain in the grain tank. For prior art agricultural harvesters, this requires that the operator stop watching the field he is harvesting, turn his head, crane his neck, and look through a small window at the top of the grain tank, to see whether the crop has reached an almost-full level. The operator will see nothing in the small window until the grain bin reaches perhaps 95% full. 
     This last-minute visualization means that the farmer may have to stop harvesting, send a radio communication and wait for the grain truck to arrive. This is a very inefficient use of the combine, since any time spent waiting and not harvesting is wasted time. 
     To give the operator a better estimate of the level of grain in the grain tank and to permit him to keep looking forward at the field he is harvesting, some manufacturers provided grain tank level sensors fixed to the wall of the grain tank. These sensors signal a circuit (when actuated) to indicate the corresponding fill level of the grain tank. The switches may be located to actuate at different fill levels, such as 75% and 100% of full. 100% of full meaning in this context that the grain tank is filled to its recommended carrying capacity. 
     In these arrangements, a visual or audible signal is provided to the operator in the operator cabin indicating the level of grain in the grain tank. Visual signals are presented in front of the operator so the operator can determine the level of grain without having to turn his head. Unfortunately, these arrangements indicate only a few levels to the operator, each level corresponding to a different level switch in the grain tank. 
     More recently, new arrangements have been invented that indicate the grain level in the grain tank with a higher resolution. For example, one design includes an ultrasonic sensor disposed above the grain tank that shines downward on the top of the grain. The ultrasonic sensor is capable of determining the height of grain in the grain tank to within a few cm. See, for example, U.S. patent application Ser. No. 11/402,782, which is assigned to Deere &amp; Co. the assignee of the present application. 
     In another arrangement, the grain level in the grain tank is calculated by integrating an inlet grain flow rate of the grain coming into the grain tank and an outlet grain flow rate of the grain leaving the grain tank via an unloading conveyor. See, for example, U.S. patent application Ser. No. 12/164,926, which is assigned to Deere &amp; Co., the assignee of the present application. 
     In both these applications, the operator is provided with the fill level of the grain tank. Since these arrangements have been developed, a new concern has arisen. The operator may not want the actual level in the tank indicated. Instead, the operator may wish to have the display indicate an arbitrary level or volume of grain in the grain tank different from the actual level or volume. For example, the operator may wish to contact the grain truck driver when the grain tank is 85% full to signal him to return for further unloading. Alternatively, the operator may want the display to indicate “full” when the grain tank is only 60% full in order to avoid getting stuck in soft ground. In both of these cases the operator has preference for displaying the grain tank as “full” at a level that he deems full under the conditions, which may be less than the absolute volumetric capacity of the grain tank. 
     To date, no system known to the inventors provides the operator with an easy way to change the scale values of the display in the operator cab. While the means described above permit the accurate measurement of the level of grain, they do not permit the operator to scale the display according to arbitrary grain tank fill levels that he deems most useful. It is an object of this invention to provide such a system. 
    
    
     
       SUMMARY OF THE INVENTION 
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of an agricultural combine in accordance with the present invention. 
         FIG. 2  is a schematic diagram of the fill level display. 
         FIGS. 3A-3F  are alternative display arrangements. 
         FIG. 4  is a flow chart of the operation of the fill level display. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In reference to  FIG. 1 , a combine  10  is shown comprising a self-propelled vehicle  12  having a feederhouse  14  extending from the front of the vehicle, and a harvesting head  16  supported on the forward end of the feederhouse. The combine  10  travels in a direction “V” over the field to harvest crop. 
     Self-propelled vehicle  12  has an operator cabin  18  located above feederhouse  14 . Behind operator cabin  18  is a grain tank  20  which has an open top  22 . A rotor  24  for threshing cut crop material is disposed to receive cut crop material from feederhouse  14 . 
     Grain threshed from the crop is conveyed to a cleaning and separating mechanism  26  disposed underneath threshing rotor  24 . Unwanted plant material separated from the grain is conveyed rearward to a chopper  28 , which chops the unwanted crop material and distributes it over the ground. 
     A grain elevator, here shown as an auger  30 , is disposed underneath the cleaning and separating mechanism  26  to gather all the grain and carry it upward where it is deposited in the grain tank  20 . 
     A first unloading conveyor  32 , here shown as an auger, has an inlet  34  (adjacent outlet  33  of grain tank  20 ) disposed at the bottom of grain tank  20 . 
     Grain exiting grain tank  20  enters inlet  34  under the force of gravity and is carried to an outlet  35  located at the other end of unloading conveyor  32 , from which the grain is expelled and falls into the grain cart or grain truck immediately adjacent to combine  10 . 
     In reference to  FIG. 2 , grain tank  20  receives grain through a grain tank inlet  38 . A flow sensor  40  is disposed at grain tank inlet  38  to sense the passage of grain into the grain tank  20 . Flow sensor  40  is coupled to electronic control unit  46  to provide a signal indicative of the rate of grain passing through grain tank inlet  38 . Grain entering the inlet  38  of grain tank  20  impinges against flow sensor  40 , which is preferably a mass flow sensor. The signal provided by flow sensor  40  is indicative of the mass flow rate flowing into grain tank  20 . 
     A level sensor  42  is disposed to sense the level of grain inside grain tank  20  in a simple form this sensor may be a switch that is configured to be actuated when submerged by grain, thus indicating that grain has reached the level of the switch at the moment it is actuated. 
     Level sensor  42  may be a switch configured to transmit a signal indicating that the grain has reach the height of level sensor  42  inside grain tank  20 . 
     An alternative level sensor  42 ′ may be employed such as an ultrasonic sensor configured to sense the level of grain in the grain tank by reflecting ultrasonic signals off the surface of the grain in the grain tank. In this arrangement, level sensor  42 ′ is capable of generating a signal indicating a plurality of grain levels in the grain tank  20 . 
     Similarly, additional level sensors (for example level sensor  44 ) may be disposed to sense additional levels of grain in the tank different than the level provided by level sensor  42 . 
     Level sensor  42  may be a switch configured to transmit a signal indicating that the grain has reach the height of level sensor  42  inside grain tank  20 . 
     An electronic controller  46  is provided to which level sensors  42 ,  42 ′, and  44  are coupled. These level sensors are configured provide signals to electronic controller  46  that are indicative of the level of grain in grain tank  20 . 
     Electronic controller  46  preferably comprises a digital microprocessor with RAM and ROM, and further with driver circuits for reading the signals from sensors  40 ,  42 ,  42 ′,  44 , processing those signals. Electronic controller  46  is configured to provide an output signal to a display  48  disposed inside the operator cabin  18  in front of the operator  50 , visible to the operator  50  when combine  10  is traveling in the forward direction of travel “V”. The output signal provided to display  48  indicates the amount of grain in grain tank  20 . 
     The grain tank has fixed contours, and thus there is a one-to-one relationship between the level of grain in the grain tank  20  and the volume, amount and weight of grain in the grain tank  20  for any particular grain that is harvested. Therefore, the level of grain in the tank provided by the sensors also provides the volume of the grain in the grain tank  20  according to a simple relationship that depends on the contours of any particular grain tank  20 . The signals from sensors  42 ,  42 ′,  44  indicate the level of grain in grain tank  20  and therefore also indicate the volume or weight of grain in grain tank  20  as well. More generally, they indicate the amount of grain in the grain tank. Similarly the signal from flow sensor  40  when integrated over time also indicates the volume or amount of grain in grain tank  20 . 
     Electronic controller  46  is configured to determine the amount of grain in grain tank  20  in a variety of ways depending upon which sensors  40 ,  42 ,  42 ′,  44  is employed. These are described in more detail herein in conjunction with  FIG. 4 . 
     During general harvesting operations electronic controller  46  is configured to determine the amount of grain in grain tank  20  as the agricultural harvester travels through he field harvesting crop, either by estimation and/or by the use of signals from one or more of sensors  40 ,  42 ,  42 ′,  44  Electronic controller  46  configured to determine a an amount of grain in the grain tank. Electronic controller  46  is further configured to send an output signal indicating the amount of grain in the grain tank  20  to display  48 , energizing the display elements of the display  48  to visually indicate the amount of grain. 
       FIG. 3A-3F  show several possible arrangements of display  48 . In  FIG. 3A , a simple arrangement of display elements is shown. These 4 elements,  50 ,  52 ,  54 ,  56  are arranged in a line, and are controlled by electronic controller  46  which sequentially energizes them starting with the element  50 , the bottom element, to indicate that grain tank  20  is filled to the 25%, 50%, 75%, and 100% level. 
     Electronic controller  46  is configured to sequentially energize each of these display elements  50 ,  52 ,  54 ,  56  as the grain tank  20  reaches each of these successive levels. 
     A similar arrangement is shown in  FIG. 3B , in which there are 10 display elements  56 , the illumination of each element indicating an additional 10% of grain tank being filled with grain. As in the previous example, electronic controller  46  is configured to successively illuminate these elements starting from the bottom as the level of grain in the grain tank  20  reaches each of these levels. In both of these arrangements, a legend is provided alongside each of the display elements to indicate the level of grain in grain tank  20 . 
       FIG. 3C  shows another embodiment, in which the display does not indicate the percentage of fill, but rather the level of grain in the grain tank indicated in bushels. In this case, each display element  58  of display  48  indicates successive increases in the level of grain in grain tank  20  of 30 bushels. 
       FIG. 3D  shows another alternative display  48  having two display elements  60 ,  62 , each of which being able to display a digit (preferably digits 0-9), and a third display element  64  configured to display the digit “1”. In this embodiment, electronic controller  46  is configured to apply a signal to display  48  causing it to display the level of grain in the grain tank  20  measured in a percentage of the total capacity of the grain tank  20 . 
       FIG. 3E  shows an alternative display  48  in which a plurality of display elements  66  are disposed in a circular arrangement. In this arrangement, electronic controller  46  is configured to successively light each of the display elements  66  just as it successively lights each of the display elements of  FIGS. 3A-3C . 
       FIG. 3F  shows another arrangement of display  48  arranged as a quadrant gauge and having a plurality of display elements  68  disposed in an arc. In this arrangement, electronic controller  46  is configured to selectively light the display elements  68  starting from the left side (identified by the number “0” and extending to the right side (identified by the number “100”). 
     Referring back to  FIG. 2 , an operator input device  70  is coupled to electronic controller  46  and is configured to be manipulated by operator  50 . When manipulated, operator input device  70  generates a signal which it provides to electronic controller  46 . Electronic controller  46 , upon receiving this signal, sets the maximum range of the display equal to the current level of grain in the grain tank  20 . Once the maximum range of the display has been changed, electronic controller  46  scales its output signal that it applies to display  48  such that display  48  generates its “full” level (i.e. 100%, or 300 bushels in the examples shown in  FIGS. 3A-3F ) whenever it determines that the level of grain has risen to the same height during subsequent grain tank filling operations. 
     Electronic controller  46  executes the series of instructions shown in  FIG. 4  to perform this task. 
     In  FIG. 4 , step  71  indicates the start of the process when the combine  10  is initially started up. In step  72 , electronic controller  46  sets “REF_LEVEL”, the reference level of grain in the grain tank equal to a default value of “X”. In the preferred embodiment, REF_LEVEL initially holds a number that equals the level of the grain tank when electronic controller  46  shows the grain tank 100% filled. It is the predetermined level of grain in the grain tank. 
     Electronic controller  46  also sets a variable called “CURR_LEVEL” to zero. Buried this variable stores the running integrated value which indicates the actual level of grain in the grain tank that is continually calculated by electronic controller  46  by integrating the signal from flow sensor  40 . 
     The grain tank is assumed to be initially empty, and hence the current level of grain in the grain tank (i.e. CURR_LEVEL) is zero. In an alternative arrangement, CURR_LEVEL, the level of grain in the grain tank, can be saved when the combine  10  is shut down. Thus, the combine could be shut with a partially filled grain tank  20  and a saved value of CURR_LEVEL that reflects this quantity of grain equal to this partially filled grain tank  20 . For ease of explanation herein, we take the simplest example: the grain tank is initially empty, and CURR_LEVEL is therefore equal to zero. 
     In step  74 , electronic controller  46  enters a polling loop which constitutes steps  74 ,  80 ,  82 , and  84  (and optionally step  86 ) in which it repetitively reads sensor  40  and performs certain additional calculations described in detail below and. 
     In step  74  electronic controller  46  polls sensor  40 . The value from sensor  40  is indicative of the instantaneous flow rate of grain into grain tank  20 . 
     In the next step, step  80 , a first arrangement of electronic controller  46  calculates the proportional fill level of grain tank  20 . Electronic controller  46  adds the sensor  40  reading to the variable CURR_LEVEL, which is the running integrated value indicating the instantaneous amount of grain in the grain tank  20 . In the preferred embodiment, electronic controller  46  calculates this fill level by dividing CURR_LEVEL by REF_LEVEL. This provides the grain level of grain tank  20  expressed as a decimal. 
     In an alternative step  80 , a second arrangement of electronic controller  46  does not monitor sensor  40 , but monitors sensor  42 ′ and uses its reading as the CURR_LEVEL of grain in the tank, and subsequently dividing CURR_LEVEL by REF_LEVEL as described above. The signal provided by sensor  42 ′ may be scaled to accommodate the different cross sectional areas of the tank. For example, a unit change in the height of the grain when the grain is at the bottom of the tank  20  indicates a much smaller change in grain quantity since the bottom of the tank has a small horizontal cross sectional area as compared to the top. 
     Putting the matter in more familiar terms, the volume of water necessary to change the height of water in a water glass by one centimeter is much smaller than the volume of water necessary to make a one centimeter change in the height of water in a swimming pool. After this calculation of the level of grain, the electronic controller  46  continues by dividing CURR_LEVEL by REF_LEVEL as described above. 
     In another alternative step  80 , a third arrangement of electronic controller  46  calculates the level of grain in the tank by adding a predetermined volume of grain to CURR_LEVEL. This requires no input from the sensors and relies on the fact that the auger  30  deposits the same predetermined quantity of grain into the grain tank  20  over every interval of time that the auger  30  is operating. After this, electronic controller  46  divides CURR_LEVEL by REF_LEVEL as described above. 
     In another alternative step  80 , a supplemental arrangement of electronic controller  46  is configured to monitor sensors  42 ,  44 , or  42  and  44  to provide additional precision. Sensors  42 ,  44  are actuated when the grain reaches the level of the sensors  42 ,  44  in the grain tank  20 . Electronic controller stores a grain tank  20  fill level associated with the actuation of each of the sensor  42 ,  44  called herein SENSOR_ 42 _LEVEL and SENSOR_ 44 _LEVEL. Electronic controller  46  supplementally monitors these sensors in step  80 . electronic controller  46  determines whether sensors  42  or  44  have changed state since the last executed step  80 . If so, electronic controller sets CURR_LEVEL equal to level of grain indicated by the sensor  42 ,  44  that just changed state (i.e. either it sets CURR-LEVEL to either SENSOR_ 42 _LEVEL or SENSOR_ 44 _LEVEL). This replaces the currently calculated CURR_LEVEL with a new CURR_LEVEL based upon the readings from sensor  42  and/or  44 . 
     In step  82 , electronic controller  46  transmits a signal to display  48  commanding it to display the proportionate level of fill of grain tank  20 . Different displays have different types of driver circuits and require different methods of communicating this information. These different methods of driving display  48  are well-known in the art, and therefore are not described in detail. It is sufficient that whatever method is provided to energize the various display elements, that the energized elements indicate the proportion of grain in the grain tank. For example, and using the example described above, if CURR_LEVEL divided by REF_LEVEL equals 0.50, display  48  should display in some manner that grain tank  20  is 50% filled. Preferably, this can be done by energizing half (i.e. 50%) of the display elements. It can also be done by driving the display of  FIG. 3D  to say “50%”. It can also be done by driving the display of  FIG. 3C  to indicate 150 bushels, which is 50% of the full range (300 bushels) of the display. Again, the manner in which the signals are sent may be complex, but the result should be as described. Intermediate proportions of fill would be similarly calculated and the display  48  driven in a similar manner to display those different proportions. 
     In step  84 , electronic controller  46  polls operator input device  70  and determines whether the operator is selecting input device  70 . If the operator has selected operator input device  70 , electronic controller  46  branches in its execution path, following the “yes” route and executes step  86 . if the operator has not selected operator input device  70 , 
     In step  86 , electronic controller  46  sets REF_LEVEL equal to CURR_LEVEL for all future loops through polling loop  76 . 
     The effect of manipulating the operator input device  70  is to set the current level of grain in the grain tank equal to 100%, and to scale all lesser quantities of grain in the grain tank (i.e. smaller numeric values of CURR_LEVEL) proportionately. From this point on, until the operator again presses operator input device  70 , electronic controller  46  will drive display  48  to display not the actual percentage of fill of the grain tank or total bushels in the grain tank, but some lesser value, equal to the percent of grain in the grain tank proportionate to the actual fill level at the time the operator manipulated the operator input device. 
     For example, assume the operator selects operator input device  70  when the actual fill level is 50%. From then on, electronic controller  46  will scale the display  48  such that “0%” appears on the display  48  when the tank is empty (i.e. 0% full), and 100% appears on the display  48  when the grain tank  20  is 50% full. 
     This may be useful, for example, if the grain cart has a limited capacity, and can only receive 50% of the grain tank capacity at that time. If this was the case, the operator would want to know when he has one grain cart&#39;s worth of grain stored in the grain tank Having display  48  show “100%” when it is time for the grain cart to unload the combine would be a convenience to the operator. 
     The operator can follow the same process to reset electronic controller  46  to its original state. Assume that the scaling in the previous two paragraphs has already been performed, and therefore that display  48  indicates a completely full state (i.e. 100% or  300  bushels) when the grain tank  20  is less than completely full. To reset the system to its original state, the operator will simply fill the grain tank  20  beyond the level at which the now-scaled display  48  shows “100%” (which was configured to occur when the grain tank  20  was only 50% full in actuality), and continuing to fill grain-tank  20  until the grain tank is 100% full in actuality. At this point, the value of CURR_LEVEL will be twice as great as the value of REF_LEVEL. 
     At this point, the operator can Select operator input device  70 . the resulting answer in step  84  of  FIG. 4  will be “yes”, and electronic controller  46  will reset REF_LEVEL to CURR_LEVEL, and display  48  will henceforth indicate “100%” when grain tank  20  is filled to an actual 100% of its capacity. According to the algorithm shown in  FIG. 4 , this has the additional effect of automatically scaling all of the intermediate values of grain tank  20  fill (i.e. 0%-99%) in a similar fashion. 
     Whenever the operator unloads the combine into the grain tank or grain truck accompanying the combine, he will reset CURR_LEVEL to 0 (using another device), and thereby always start filling an empty grain tank  20  with CURR_LEVEL set to zero. This resetting can occur in a variety of ways, for example by another operator input device. 
     In another arrangement, CURR_LEVEL can be determined by monitoring the signal from alternative sensor  42 ′, which indicates the actual height of grain in the grain tank  20 . Since the contours of the grain tank are fixed, the height of grain in the grain tank  20  at any time corresponds to a corresponding quantity of grain in the grain tank. Thus, electronic controller  46  can alternatively read the signal from sensor  42 ′ in step  74 , and in step  78  calculate CURR_LEVEL from that value by applying a mathematical operator to the value, the mathematical operator being a function of the contours of the particular grain tank. 
     In yet another alternative arrangement that employs one or both of sensors  42 ,  44 , electronic controller  46  can increment CURR_LEVEL in proportion to the amount of time that auger  30  is operating and filling grain tank  20 , thereby estimating the current level of grain in the tank as a function of the amount of time that auger  30  operates. This value can be corrected whenever the level of grain reaches the predetermined level of grain at which sensor  42  or sensor  44  are actuated. Since sensor  42  and sensor  44  are at predetermined physical heights within the grain tank, each corresponds to an absolute level of grain in grain tank  20 .