Abstract:
A harvesting machine includes a pick-up unit for picking up the harvested crop, a cutting device that is equipped with at least one cutting edge that cooperates with a counter-cutter for cutting and/or chopping the harvested crop, and a monitoring device, which can be operated to generate a signal containing information about the sharpness of the edge and/or its distance to the counter-cutter, with the sharpness and distance each being compared to a target value. The monitoring device receives signals generated by an optical sensor, which visually monitors the cutting device and/or the cut harvested crop, wherein the signal of said sensor is used so that the monitoring device can deduce information about the sharpness of the edge and/or its distance to a counter-cutter, and send out a control signal for effecting automatic sharpening of the cutting edge and/or adjustment of the counter-cutter.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention relates to a harvesting machine comprising a pick-up unit for picking up the harvested crop, a cutting device that is equipped with at least one edge for cutting and/or chopping the harvested crop, and a monitoring device, which can be operated to generate a signal containing information about the sharpness of the edge and/or its distance to a counter-cutter, which is compared to a target value.  
       BACKGROUND OF THE INVENTION  
       [0002]     Harvesting machines of the above kind, such as forage harvesters, baling presses or forage wagons, are equipped with cutting devices for cutting and/or chopping the harvested crop. Such cutting devices are also used on harvester-threshers to chop the threshed straw, if desired. For the cutting results it is important that the edge or edges of the cutting device are sufficiently sharp. In the case of dull edges the energy that is required for the cutting operation increases. If the harvested crop is not chopped in a freely cutting manner, i.e. without the use of a counter-cutter, a counter-cutter may be useful. The distance between the counter-cutter and the edge is likewise critical and should be adjusted as accurately as possible.  
         [0003]     In the currently commercially available harvesting machines it is up to the driver to decide whether and when a sharpening operation of the edge occurs. Adjustment of the counter-cutter currently also only occurs at the request of the driver.  
         [0004]     In various publications devices have been described for determining the sharpness of chopping blades. Pursuant to DE 40 23 113 A and DE 40 23 114 A the tension induced by the edges in inductive transmitters is evaluated. DE 199 03 153 A suggests the detection of the cutting forces. DE 102 35 919 A and DE 103 03 504 A reveal the mechanical detection of vibrations of the counter-cutter to determine sharpness.  
         [0005]     To measure the distance between the edges and the counter-cutter a series of devices have been suggested (DE 41 34 957 A, DE 43 35 786 A, EP 0 706 752 A), in which a vibration sensor is attached on the counter-cutter, the output signal of which sensor is a function of the distance between the counter-cutter and the chopping blades. To measure the distance between the counter-cutter and the chopping blades moreover also magnetic sensors are known, which comprise a permanent magnet that is connected with the counter-cutter and an induction coil, in which the passing chopping blades induce an electro-motive force, which is amplified and detected (EP 0 943 888 A).  
         [0006]     DE 38 16 206 A describes a cutting device for double fabrics, which comprises a knife, whose exact positioning and sharpness is examined by means of an opto-electrical sensor. It is composed of a camera, which detects the knife, and an electronic evaluating unit. Said publication discloses no suggestions for using the sensor in an agricultural harvesting machine.  
         [0007]     Furthermore a series of publications is available in which the harvested crop is monitored visually. U.S. Pat. No. 6,119,442 A describes a harvester-thresher, in which a camera is directed at the harvested crop being processed. The camera signals are evaluated and compared to target values. The operating parameters of the harvester-thresh are modified as a function of the results of the comparison. EP 1 053 671 A suggests to examine the chopped harvested crop by means of a sensor operating in the near infrared region so as to detect contents. The measurement values of the sensors can also be used to deduce characteristics of the harvested crop, such as crude fiber content or fiber length. These publications do not reveal that the signals of the optical sensors are suitable for determining sharpness or for measuring the distance between the counter-cutter and edge.  
       SUMMARY OF THE INVENTION  
       [0008]     It is the object of the invention to provide an improved harvesting machine, in which the decision as to whether sharpening of the edge or an adjustment of the counter-cutter is required can be made automatically and accurately.  
         [0009]     An object of the invention is to provide a harvesting machine including a chopper equipped with a monitoring device for checking the condition of the cutting blades and/or the distance between the cutting blades and the counter-cutter and/or crop condition, with the monitoring device being coupled to a control arrangement for initiating one or the other of a sharpening routine and/or a counter cutter adjusting routine when the monitored condition indicates such action is desirable.  
         [0010]     The foregoing object is achieved by providing a monitoring device with an optically operating sensor, which can be operated such that it monitors the cutting device visually. Its signal is used to deduce information about the sharpness of the edge and/or its distance to the counter-cutter. This system also allows the detection of defective blades and shifted blades. Alternatively, or additionally, the harvested crop that is chopped by the cutting device, the cut length and quality of which depends on the sharpness of the edge and possibly its distance to the counter-cutter, is visually monitored by a sensor, and the sensor&#39;s signal is used to gain information about the sharpness of the edge and/or its distance to the counter-cutter. The monitoring device provides an output signal, which contains information about the sharpness of the edge and/or the distance to the counter-cutter. The output signal and/or information deduced thereof is compared by the driver or automatically with a target value.  
         [0011]     One advantage of using optical sensors is the accuracy that can be achieved. The sensors can, different from the inductive or mechanical sensors used in the prior art, be attached at a specific distance to the cutting device and hence in a position in which they are exposed to the influence of the harvested crop and the vibrations caused by the cutting device only to a relatively limited extent. Moreover a missing or defective cutting blade can be detected immediately, and the driver can be informed.  
         [0012]     Depending on the results of the comparison, the driver can be provided with a visual or acoustic indication, which causes him to perform a sharpening operation and/or to re-adjust the distance between the cutting device and the counter-cutter. The above operations can also be performed automatically without intervention by the driver, possibly while driving or during the harvesting process. The sharpening operation can likewise be detected by the optical sensor so that in the case of a sharpening operation that is terminated at a suitable time based on the signals of the sensor no more material than is required is actually ground off. Similarly, the adjusting operation is terminated as a function of the signal of the optical sensor.  
         [0013]     In one embodiment of the invention, the sensitive area of a sensor of the monitoring device is directed at the cutting device. Hence it detects the shape of the cutting edges of the blade and is adjusted such that it detects its sharpness. If it is also supposed to detect the distance between the edge and the counter-cutter, the sensor preferably additionally also detects the counter-cutter.  
         [0014]     Various possibilities for designing the optical sensor are feasible. On one hand, it can be an imaging sensor, i.e. a camera, which comprises a large-surface image sensor with one- or two-dimensional resolution. Its signal is preferably digitized and processed by means of an image processing software. The result of this processing operation represents information about the sharpness of the edge and/or its distance to the counter-cutter. In order to achieve sufficient illumination, it may be useful to expose the area that is to be depicted to a secondary light source. The light source can illuminate the area in points and scan the surface that is to be examined or it can illuminate a large surface. On the other hand, it can be a non-imaging sensor, i.e. a light-sensitive element, which emits a signal as a function of its illumination level. Such sensors can be used in particular with scanning light sources, e.g. lasers. The sensors described in this paragraph can be used to detect the cutting device and possibly the counter-cutter, and also can be used for detecting the condition of the harvested crop released by the cutting device.  
         [0015]     Especially for examination of the cut harvested crop an optical sensor (spectrometer) can be employed, which operates in the near infrared region. The cut edges of the harvested crop offer different spectra than the uncut surfaces since they have a different surface composition. The spectra that are gained can hence be used to calculate the surface ratio between uncut and cut surfaces and the cut length. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     The drawing shows two embodiments of the invention, which are described more closely in the following.  
         [0017]      FIG. 1  is a schematic, left side view of a harvesting machine constructed pursuant to the invention.  
         [0018]      FIG. 2  is a schematic, left front perspective view of a first embodiment of a monitoring device constructed pursuant to the invention.  
         [0019]      FIG. 3  is a schematic, left front perspective view of a second embodiment of a monitoring device constructed pursuant to the invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0020]     A harvesting machine  10 , illustrated in  FIG. 1  in form of a self-propelled forage harvester, is composed of a frame  12 , which is supported by front and rear wheels  14  and  16 . Operation of the harvesting machine  10  occurs from a driver cabin  18 , from where a pick-up unit  20  for picking up the harvested crop is visible. Harvested crop that is picked up by means of the pick-up unit  20 , e.g., corn, grass or the like, is fed to a cutting device  22  comprising a chopper in the form of a closed cylinder having a plurality of cutting blades  62  arranged about its circumference. The forward edges of the cutting blades  62  cooperate with a counter-cutter or shear bar  38  to chop the harvested crop into small pieces and forward them to a conveying device  24 . The crop leaves the harvesting machine  10  and enters a trailer following along the side of the machine via a discharge chute  26  that can rotate about the vertical axis and is adjustable in its tilt. A kernel processor  28  extends between the cutting device  22  and the conveying device  24 , with which the conveyed harvested crop is fed tangentially to the conveying device  24 .  
         [0021]     The crop is transported between the pick-up unit  20  and the cutting device  22  by a feed roll arrangement including lower pre-pressing rollers  30 ,  32  and upper pre-pressing rollers  34 ,  36 . The counter-cutter  38  is equipped with an adjusting device  40 , which is arranged such that the counter-cutter  38  can travel in the horizontal direction towards the cutting device  22  and away from it. The adjusting device  40  serves to adjust the cutting gap.  
         [0022]     On the top of the discharge chute  26 , an optical (spectroscopic) sensor  68  operating in the near infrared region is arranged, which contains a spectrometer. It supplies the shredded crop flowing through the discharge shaft  26  with broad-band infrared light. The light reflected by the harvested crop is subjected to a wavelength analysis. Based on the spectra that are gained, the contents of the harvested crop can be identified and quantified. Moreover, the spectra contain information about the cut length of the harvested crop since the cut surfaces emit different spectra than those of uncut surfaces. The sensor  68  can be designed as described in EP 1 053 671 A, the disclosure of which is hereby included in the present document by way of reference.  
         [0023]     The monitoring device pursuant to the invention for monitoring the sharpness of the cutting blades  62  as well as the distance between the counter-cutter  38  and the cutting blades  62  of the cutting device  22  is illustrated in more detail in  FIG. 2 . It comprises a monitoring device  42 , which is connected to a first camera  44 . The first camera  44  consists of a lens  46 , an image sensor  48  (e.g. CCD) and a housing  50 . Apart from the camera  44  a first illuminating device  52  comprising a lamp  54  and a collimator  56  is installed. A second camera  58 , the design of which is in agreement with that of the first camera  44 , is likewise connected to the monitoring device  42 . The second camera  58  is assigned a second illuminating device  60 , the design of which agrees with that of the first illuminating device  52 .  
         [0024]     The first illuminating device  52  is arranged in the upper region of the cutting device  22  and illuminates it across a large area. The first camera  44  detects the top of the cutting device  22 . In relation to the driving direction of the harvesting machine  10 , the second illuminating device  60  is located to the right above the counter-cutter  38  and the area of the cutting device  22  adjacent to the counter-cutter  38  and illuminates all the mentioned surfaces. The second camera  50  is located in relation to the driving direction of the harvesting machine  10  to the left above the counter-cutter  38  and the region of the cutting device  22  adjacent to the counter-cutter and monitors the aforementioned surfaces.  
         [0025]     The lenses  46  create images of the cutting blades  62  (camera  44 ) and the cutting gap as well as the region adjacent to the cutting gap of the cutting blade  62  and the counter-cutter  38  (camera  50 ) on the image sensors  48 .  
         [0026]     The signals of the image sensors  48  are fed to the monitoring device  42 . There they are digitized and subjected to an image processing operation, in which, on one hand, based on the signals of the camera  44 , the cutting edges of the cutting blades  62  are extracted and compared to a target shape. If this shows that the cutting edges are not sufficiently sharp, a sharpening device  76  is activated or the driver is provided with an appropriate message. Analogous to this, the sharpening operation is terminated as a function of the signals issued by the camera  44 .  
         [0027]     On the other hand, the gap between the counter-cutter  38  and the cutting blades  62  is extracted from the signals of the camera  50  and compared to a target distance. When it is larger or smaller than corresponding, pre-defined limit values, the monitoring device  42  initiates the automatic activation of the adjusting device  40  in order to bring the counter-cutter  38  into a target position in relation to the cutting blades  62  or indicates to the driver to proceed accordingly. Here as well, the motion of the adjusting device  40  is terminated when the monitoring device  42  detects, based on the signals from the camera  50 , that the counter-cutter  38  has reached its target position.  
         [0028]     The monitoring device  42  also receives signals from the spectroscopic sensor  68 . It conducts a comparison between the cut length that the spectroscopic sensor  68  measured and the cut length that is calculated based on the speed of the cutting device  22  and the pre-pressing rollers  30 - 36 . When the cut length is greater than expected, the sharpening device  76  likewise initiates a sharpening operation, either automatically or by informing the driver. If the signals of the spectroscopic sensor  68  indicate an insufficient cut quality (too large, frayed surface due to unclean cut), then an adjustment of the counter-cutter  38  can be initiated.  
         [0029]     It would also be feasible to forego the second camera  50  and the second illuminating device  60  if only the sharpness of the cutting blades  62  is supposed to be detected. It would also be feasible to use the second camera  50  to determine the sharpness of the cutting blades  62  and forego the first camera  44  and the first illuminating device  52 . It would also be possible to use only the spectroscopic sensor  68  or forego it.  
         [0030]     In the described measuring process in particular, the detection of the cutting edges of the cutting blades  62  is problematic when the cutting device  22  is rotating. Here it is recommended to use a camera  44  with a corresponding speed and resolution or to equip it with a high speed shutter, or to take advantage of the pulsed illuminating device  52 , which emits flashes that are sufficiently short. Alternatively, or additionally, the camera  44  is only used when the cutting device  22  rotates relatively slowly or stands still. Since the camera  50  will only be used to detect the gap between the counter-cutter  38  and the cutting blades  62 , so that a less than sharp image of the cutting blades  62  due to the rotating cutting device  22  is insignificant, while the diacaustic curve they travel is of interest, measurements are less critical.  
         [0031]     A second embodiment of the invention is illustrated in  FIG. 3 . Elements that agree with the first embodiment have been marked with the same reference numbers. Here a laser  64  is used, which, in relation to the driving direction of the harvesting machine  10 , is arranged to the right above the counter-cutter  38 , i.e., where in  FIG. 2  the second illuminating device  64  is located. The laser  64  can be adjusted in two dimensions by means of an adjusting device  66 , i.e., it can swivel motor-driven about the vertical axis and about a horizontal axis extending in the driving direction of the harvesting machine  10 . A camera  70 , the design of which agrees with that of the cameras  44 ,  50  from  FIG. 2 , is arranged in relation to the driving direction of the harvesting machine  10  to the left above the counter-cutter  38 , i.e., where in  FIG. 2  the second camera  50  is located. The adjusting device  66  and the camera  70  are connected to the monitoring device  42 . Instead of the camera  70 , it would also be feasible to use a non-imaging sensor in form of a photodiode or the like.  
         [0032]     The monitoring device  42  causes the adjusting device  66  to gradually scan the gap between the counter-cutter  38  and the cutting blades  42  and the surfaces adjacent to the gap of the counter-cutter  38  and the cutting blades  62  in the driving direction and the perpendicular, horizontal direction thereto. Hereby the camera  70  generates information on the width of the gap. Additionally, based on the light that is reflected by the cutting blades  62 , a conclusion can be drawn about their sharpness. Equivalent to the first embodiment, the sharpening device  76  and/or the adjusting device  40  of the counter-cutter  38  is activated automatically when, during the analysis of the digitized output signals of the camera  70  by means of the image processing software, it is found in the monitoring device  42  that the sharpness and/or gap width are not in agreement with the target values and/or corresponding information is forwarded to the driver. The sharpening and/or adjusting operations are terminated likewise preferably based on corresponding signals of the camera  70 .  
         [0033]     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.