Measuring and testing – Volume or rate of flow
Reexamination Certificate
1999-02-03
2001-09-04
Raevis, Robert (Department: 2856)
Measuring and testing
Volume or rate of flow
Reexamination Certificate
active
06282967
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to agricultural machinery and, more particularly, to improvements for measuring the throughput of material on conveyors.
The invention specifically relates to an apparatus for measuring where the conveyer blades carrying the material (in particular, cereal grains) are continuously moved in a conveyer shaft. A photoelectric device is mounted on the shaft so that its light beam is aligned substantially parallel to the preferably flat surfaces of the blades. A signal processor determines the distance between the top edge of the material and the passing blade carrying the material from the light-dark periods of the signal. The signal processor determines the apparent volume of material on each blade, taking into account the spacing of the blades, the thickness of the blades, and the cross-sectional area of the shaft.
An apparatus of this general type is known from German patent 30 45 728 C2. Conveyer blades carrying the harvested material (in particular, cereal grains) are aligned approximately perpendicularly to the walls of a rectangular conveyer shaft. An endless chain continuously pulls the conveyor blades through the shaft. The surface of the layer of grain on the blade is approximately horizontal. The shaft is mounted on a combine harvester and is usually inclined to the vertical in the plane of the chain. A photoelectric device is mounted in parallel with the blades and is effective between the side walls of the shaft. The dark period of the light beam for the pass of each loaded blades is measured. The height of the load is determined, taking into account the dark period due to the thickness of the blade itself. The volume of grain being conveyed is determined by multiplying the height by the area of the shaft or a function of the shaft geometry. This apparatus only works relatively accurately when the combine harvester is on a horizontal surface so that the conveyer is in its normal position and when the blades are sufficiently full. However, if the conveyer is transversely or longitudinally inclined relative to its normal position, such as when it is being moved on a slope or at different loadings of the grain tank or when crossing loose earth, its operation is impaired and the computed result is extremely inaccurate. Under such circumstances, the measurement of the volume of grain being conveyed is usually too high.
Furthermore, it is known from German patent 195 44 057 A1 that in order to correct the weight of corn being conveyed in an inclined conveyer, where the weight is being systematically underestimated by a weighing sensor, one may calculate the true quantity of conveyed corn by means of a signal from an inclinometer functioning in two directions. However, this weighing apparatus for the conveyer is complex and the need to decouple the drive mechanism therefrom is also technically complex.
Moreover, it is known from European patent 0 702 891 A1 to associate location data, speed signals and throughput time constants with continuously measured amounts in a harvesting machine so as to establish a harvesting cadastre. Here, one falls back on stored or externally defined standard litre-weights with respect to average quality and average moisture content for the different sorts of cereals. The harvest production performance and the relative losses associated therewith are continuously displayed on an indicator.
An object of the present invention is overcome one or more of the deficiencies noted above.
Another object is to provide an improved measuring apparatus having improved accuracy.
Still another object is to provide an improved apparatus of the type described and having a simplified construction.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided a conveyer for harvested crops having an apparatus for measuring the throughput of material being conveyed through the conveyer, conveyer blades for carrying the material, means for continuously moving the blades in a conveyer shaft, a first photoelectric device mounted so that its light beam is aligned substantially parallel to the surfaces of the blades, a processor for determining the distance between the top edge of the material and the passing blade carrying the material from the light-dark periods of the signals, said processor taking into account the spacing of the blades and thickness of the blades and determining the apparent volume of the material on each blade from said distance and the cross-sectional area of the shaft, sensing means for emitting a photoelectric beam for sensing the orientation and position of the surface of the material on a conveyor blade relative to the light beam and for sending the same to the processor, and the processor being operative to determine the inclination and shape of the surface of the material on a conveyor blade and the volume of the material being conveyed.
The object of the present invention is achieved by connecting sensing means to the signal processor which then determines the inclination and/or shape of the surface of the material via the signals from said further measuring means and finally determines the exact volume of the material being conveyed, depending upon the orientation and position of the surface relative to the light beam.
To accurately determine the volume, the volume measurement effected by the photoelectric device is corrected, taking into consideration the inclinations of the grain surface relative to the surface of the blade both in the direction of the test beam and the direction perpendicular thereto. For this purpose, the inclinations are determined using additional photoelectric devices or separate inclinometers or a combination of the both.
A first advantageous grain volume measuring apparatus is equipped with three photoelectric devices, one of which is located exactly in the middle between two opposite side walls. The other two photoelectric devices are arranged at right angles to the first and are located near the edges of the shaft. Preferably all three photoelectric devices are located at the same height. Any swaying of the shaft exclusively about the axis of the first, central light beam has no effect upon the dark-time or depth measurement, i.e., the period of time between the passing of the base of the blade and the top surface of the grain. The other two photoelectric devices indicate an equal rim level of the grain, which is greater than the relevant depth measured by the first photoelectric device, which depends upon the amount of sway and the half width of the shaft.
If, however, the shaft should only sway about the axis of the other light beams then the inclination will be given by the differing dark-time or depth signals caused thereby in relation to the spacing between the photoelectric devices. The relevant central height of the grain with respect to the half width of the shaft can then be easily determined from the maximum length of the rim as measured by the first photoelectric device and the aforesaid inclination.
If the shaft is inclined differently about the axes of both photoelectric devices, the relevant height of the grain surface needed for determining the volume is likewise given by the length of the rim as measured by the first photoelectric device but reduced by the difference in the length of the rim up to the center of the shaft caused by the inclination. The difference corresponds to the inclination determined by the other two photoelectric devices in relation to the half width of the shaft.
If the two parallel photoelectric devices for determining the inclination are mounted at a spacing corresponding to half the width of the shaft, then no additional conversion is required since the measured difference in length can be deduced directly from the length measured by the first photoelectric device for obtaining the relevant average length.
If, however, the two parallel photoelectric devices are spaced apart by more than half the width of the shaft, then the measurements are more accurate. However, the accuracy of the
Homburg Helmut
Kollmeier Klaus
Claas Selbstfahrende Erntemaschinen GmbH
Husch & Eppenberger LLC
Kercher Kevin M.
Muir Robert E.
Raevis Robert
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