Abstract:
Disclosed is a sensor for detecting the presence of a crop flow in a harvesting machine. The sensor is designed to emit an output signal containing information on whether crop material is passing through the harvesting machine or not. It is suggested that the sensor be designed to detect vibrations produced during the processing and/or transporting of the crop flow in the harvesting machine. Such a sensor is especially suitable for use with arrangements for calculating the area from which crop is being harvested and for mapping yields.

Description:
FIELD OF THE INVENTION 
   The invention relates to a device for detecting the presence of a crop flow in a harvesting machine with a sensor designed to emit an output signal containing information on whether crop material is passing through the harvesting machine or not. 
   BACKGROUND OF THE INVENTION 
   Sensors, for measuring the throughput of crops and based on different physical principles, are used in harvesting machines for indicating the yield and/or for yield mapping. The sensors measure the crop throughput within certain error tolerances. In many systems, throughputs below a certain threshold value can no longer be precisely measured. It is also conceivable, due to the error tolerances of the sensors, that throughputs are measured even though no crop is transported through the harvesting machine. 
   Harvesting machines are, as a rule, also provided with so-called hectare or acre counters or meters used to measure the harvested area. They continue to count a measuring value representing the worked surface if a number of conditions have been met, such as positive, i.e., forward, travel speed, front attachment in harvesting position, and if the crop processing and/or transport devices are in an operating mode. Since the presence of crop material is not checked, the harvested area continues to be counted even if no flow of crop material is actually present. Even given a logical linkage to the signals of the sensors for measuring the crop throughput, the corresponding information is not always correct, and results in incorrect area values. 
   The suggestion was therefore made to combine the sensor for measuring crop throughput with a sensor for detecting the presence of crop flow. To this end, U.S. Pat. No. 6,401,549, which corresponds to DE 199 03471 C uses a light barrier in the discharge device of a field chopper. A measured value different from zero for the crop flow is emitted only if it detects a crop flow. However, the light barrier requires an additional structural component whose parts coming in contact with the crop flow wear down and can become contaminated after being used for a rather long time. 
   Acoustic sensors are used in combines to detect lost grain. They detect oscillations caused by lost grain falling onto impact plates or rods. 
   SUMMARY OF THE INVENTION 
   The invention has the basic problem of making available an improved device for the detection of the presence of a crop flow. 
   An object of the invention is to provide a harvesting machine incorporating a crop flow detecting device which detects vibrations produced during the processing and/or transporting of the crop flow in the harvesting machine. 
   The invention suggests detecting the presence or the absence of the crop flow in the harvesting machine acoustically. If a crop flow is present, it causes noises during the processing and/or during the transport in the harvesting machine. The sensor detects these noises, that is, mechanical or acoustic oscillations. The desired information about the presence of the crop flow is derived from the output signal of the sensor. 
   In this manner, the desired information is obtained by a sensor that can be arranged outside of the crop flow, is not subject to any wear, and is not contaminated during operation. 
   Various embodiments can be considered as the sensor. It would be conceivable to use a microphone that is advantageously arranged in the vicinity of a location at which the crop flow causes the highest possible noise level in order to allow the best possible differentiation from background noises. The microphone can detect the vibrations purely by air sound, i.e., acoustically, or by body sound, i.e., mechanically. It can, in particular, be a knocking sensor, like the one known in devices for adjusting the countercutting knife edge or shearbar in field choppers. It is also conceivable to use a sensor that detects the vibrations optically, e.g., with a laser beam that strikes elements that vibrate upon the presence of a crop flow. The reflected beam, whose direction is influenced by the vibrating elements, is detected by a position-sensitive detector. 
   The output signal of the sensor can also be used to control other elements of the harvesting machine. If, for example, a knocking sensor arranged on the countercutting knife edge of a chopper drum is used, its output signal can be used to adjust the position of the countercutting knife edge as well as to verify a crop flow. In another embodiment, the sensor is arranged on the threshing concave of a combine. Its output signal can be used to adjust the slot of the threshing concave. 
   The sensor, in accordance with the invention, can be used in an area-detecting device, a so-called hectare counter or acre meter, to differentiate the areas on which the actual harvesting is taking place from the remaining areas. The area is only counted if a crop flow is actually present. 
   The sensor can also be used in yield display devices and/or yield mapping devices to only consider values referring to the amount of crop taken up when the sensor furnishes a signal indicating that a crop flow is actually present. Otherwise, the amount of yield is detected as zero. Such yield mapping devices generally operate in a geo-referenced manner. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawings show two exemplary embodiments of the invention that are described in detail in the following. 
       FIG. 1  is a somewhat schematic, left side elevational view of a field chopper. 
       FIG. 2  is a somewhat schematic, right side elevational view of a combine. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring now to  FIG. 1 , there is shown a harvesting machine  10  in the form of a self-propelled field chopper including a main frame  12  carried by front and rear pairs of wheels  14  and  16 , respectively. The harvesting machine  10  is operated from an operator cab  18  located on a forward part of the frame  12  and from which one can view a crop pickup device  20 . Crop material, e.g., corn, grass or the like taken up from the ground by the crop pickup device  20 , is fed to a chopper drum  22 , that chops the crop into small pieces and impels the crop to a transport device or blower  24 . The crop leaves the harvesting machine  10  to a trailer moving alongside via rotatable discharge spout  26 . Comminuting device or kernel processor  28  is located between the chopper drum  22  and the transport device  24  and tangentially feeds the crop to be transported to transport device  24 . 
   The crop is transported between crop pickup device  20  and the chopper drum  22  through lower compression rollers  30  and  32  and upper compression rollers  34  and  36 . The knives distributed over the circumference of chopper drum  22  cooperate with countercutting knife edge or shearbar  38  in order to chop the crop. Countercutting knife edge  38  is provided with adjustment device  40  that is set to move countercutting knife edge  38  in a horizontal direction toward, or away from, the chopper drum  22 . It serves to adjust the cutting slot. A knocking sensor  42  is arranged on the countercutting knife edge  28 . It detects the noises caused by the knives of chopper drum  22  when countercutting knife edge  38  comes closer to chopper drum  22 . The output signals of the knocking sensor  42  are used in a known manner to adjust the position of countercutting knife edge  38 . 
   A throughput sensor  44  is associated with the upper rear compression roller  36 . The compression roller  36  can be moved up by the crop against the force of a spring. Throughput sensor  44  comprises a potentiometer that is adjusted upward by compression roller  36  during its movement. Thus, the throughput sensor  44  produces information about the particular throughput. The throughput sensor  44  is connected to a computer  46  arranged in the operator cab  18 , of which the computer is also connected to a position sensor  48 , that is shown in the form of a GPS antenna as an exemplary embodiment. 
   The computer  46  detects the signals of the throughput sensor  44  and of the position sensor  48  during the harvesting and makes a geo-referenced yield map and also produces a yield display for the operator. An advance or travel speed signal can also be taken into consideration, thereby, that is produced by a known sensor. The yield signal can also be used for automatic control of the advance speed. Since the separation between upper rear compression roller  36  and rear back compression roller  32  does not differ substantially or not at all, given small crop throughputs, from the separation that they assume when there is no throughput at all present, throughput sensor  44  would actually display non-existent measured values in the case of low or lacking throughputs, which however, would be displayed and mapped. 
   In order to improve the accuracy of the yield display and yield mapping, the computer  46  is connected to the knocking sensor  42 . Its analog output signals are digitized in the computer  46  or by a separate transducer. Knocking sensor  42  supplies an output signal whose amplitude and/or frequency contain information about whether crop material is being processed or not at the time, since the chopping of the crop material causes mechanical oscillations in the countercutting knife edge  38  that are picked up by the knocking sensor  42 . The measured values supplied by throughput sensor  44  are only mapped as differing from zero if the output signal of knocking sensor  42  indicates processed crop material. This avoids the above-described mapping errors. 
   Moreover, computer  46  detects the size of the area harvested by the harvesting machine  10 . The signal of the position sensor  48  is used for this. In an analogous manner, the computer  46  detects an area that has been traveled over as having been harvested only when the output signal of the knocking sensor  42  indicates that crop material is being processed. Signals indicating the operating state of the crop pickup device  20  and of the chopper drum  22  can also be considered in the detection of areas. 
     FIG. 2  illustrates a second embodiment of the invention that shows a harvesting machine  10  in the form of a self-propelled combine. It comprises a main frame  50  supported in a movable fashion by a wheel arrangement, comprising rear, steerable wheels  52  and front, driven wheels  54 . 
   A vertically adjustable front harvesting attachment  56  with a mowing beam is used to cut off standing crop material and supply cut material to an oblique conveyor  58 . The oblique conveyor  58  is pivotably connected to the main frame  50  and comprises a conveying device for feeding the harvested material to a guide drum  60 . The guide drum  60  conducts the material upward through the inlet transition section  62  to a rotatable threshing and separating device  64 . Other orientations and types of threshing devices and other types of front harvesting attachments  56 , such as transversally arranged frames carrying individual units in rows, could also be used. 
   The rotating threshing and separating device  64  threshes and separates the harvested crop. The grain and chaff fall through grates on the bottom of the threshing and separating device  64  into a cleaning system  66 . The cleaning system  66  removes the chaff and conveys the clean grain to an elevator  68 . The elevator  68  for clean grain, deposits the clean grain in a grain tank  70 . The clean grain in the grain tank  70  can be unloaded by an unloading auger  72  onto a truck or a trailer. 
   Threshed, grain-free straw is fed from threshing and separating device  64  through an outlet to an ejection drum  74 . The ejection drum  74  ejects the straw at the back of the combine  10 . Note that the ejection drum  74  could also supply the material freed of grain directly to a straw chopper. The operation of the harvesting machine  10  is controlled from an operator cab  76 . 
   The rotatable threshing and separating device  64  comprises a cylindrical rotor housing  78  and a hydraulically driven rotor  80  arranged in the rotor housing  78 . The front part of rotor  80  and rotor housing  78  define a loading section. A threshing section, separating section, and outlet section are downstream from the loading section. The rotor  80  is provided in the loading section with a conical rotor drum comprising helical loading elements for engaging into material that it receives from the guide drum  60  and from the inlet transition area  62 . The threshing section is located immediately downstream from the loading section. In the threshing section, rotor  80  comprises a cylindrical rotor drum provided with a number of threshing elements in order to thresh the material received from the loading section. The separating section is located downstream from the threshing section, in which separating section, the grain still caught in the threshed material is set free and falls through a bottom grate in the rotor housing  78  into the cleaning system  66 . The separating section merges into an outlet section in which the straw freed from the grain is ejected from the threshing and separating device. 
   The throughput sensor  81  is in the form of a known impact plate sensor and is arranged at the outlet of elevator  68  in the transition housing  82 . The grain coming out of the elevator  68  is transported on the bottom of the transition housing  82  by the auger  84  into the grain  70 . A computer  86  is electrically connected to the throughput sensor  81  and a position sensor  88 , shown here as a GPS antenna. The computer  86  can be operated during the harvesting operation, and by using measured values of the throughput sensor  81 , to prepare a geo-referenced yield map and to display the instantaneous yield to the operator. Since the measured values of the throughput sensor  81  have a fair number of errors in the instance of relatively low yields, the computer  86  is connected to another sensor  90  designed to detect whether a crop flow is present at all. The measured values of throughput sensor  81  are only viewed as differing from zero if the sensor  90  indicates the presence of crop flow. Computer  86  can, as in the first embodiment, detect the harvested area, during which the signals of the sensor  90  are considered in the described manner. 
   The sensor  90  is arranged on the threshing section of the rotor housing  78  of the threshing and separating device  64 . The sensor  90  is an acoustic sensor and detects mechanical vibrations generated by the crop during threshing. The signals of sensor  90  are digitized and supplied to the computer  86 . Using the frequency and/or amplitude of the signals of sensor  90 , computer  86  recognizes whether crop is being processed or not. The signals of sensor  90  can also be used to automatically adjust the separation between the rotor  80  and the threshing concave. 
   It remains to be pointed out that the sensor  90  can also be associated with tangentially loaded threshing drums of combines with straw shakers or of combines with separating rotors arranged after a tangential threshing drum. In each instance, this sensor detects the noises caused during the threshing of crop material. 
   Sensor  90  could also be arranged in the oblique conveyor  58  and detect noises caused by the crop when striking edges or when passing any surface. Such sensors are currently being used for detecting stone-like objects (U.S. Pat. No. 4,343,137 A). 
   Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.