Crop threshing or separating – Cleaner – Sieve or grate
Reexamination Certificate
1999-08-17
2001-05-29
Will, Thomas B. (Department: 3671)
Crop threshing or separating
Cleaner
Sieve or grate
C460S085000, C460S090000, C460S145000
Reexamination Certificate
active
06238285
ABSTRACT:
BACKGROUND OF INVENTION
1. Field of Invention
The present invention relates to agricultural harvesting machines, such as combine harvesters, and more particularly to the cleaning means for separating the crop product from discardable material, such as chaff or straw particles.
2. Description of Prior Art
Commonly, combine harvesters comprise a plurality of sieves installed below the threshing concave and straw walkers for receiving the mixture of grain kernels, chaff and short straw from the threshing mechanism and separating the discardable material therefrom while guiding the kernels to a conveyor arrangement for transport to a grain tank on top of the harvester. A fan installed below the sieves assists in making the discardable material airborne and conveying it out of the harvester.
In order to optimize the effectiveness of the cleaning arrangement the mixture of threshed material has to be guided to the sieves in a uniform and even manner. Therefore a grain pan having a corrugated surface is installed below the threshing mechanism. The grain pan is linked to the sieves and is oscillated in unison therewith. The threshed material collected on the grain pan is spread out and conveyed rearwardly to the upper sieve in an even layer.
It has been experienced with certain threshing configurations such as axial flow threshing and separating systems, that the length of the grain pan is sometimes insufficient for completely leveling this layer by the time it reaches the sieves, such that one portion of the upper sieve might get overloaded while another portion might hardly be covered with the crop and chaff mixture. Then the sieve arrangement is not working efficiently as not the full sieve surface is utilized and, moreover, the wind distribution pattern of the fan is disturbed because part of the wind is escaping with no significant resistance through the low load sections of the sieves. The consequent pressure drop also affects the cleaning action on the fully loaded sieve portions. Hence, there is a need for supplementary measures in order to improve the distribution of the threshed crop material at the end of the grain pan.
It is well known in the art to provide upright dividers on the corrugated surface of the grain pan to prevent sideways movement of the crop material. This is particularly useful when the combine harvester is traveling on sideways slopes. Such dividers may also be installed at an angle to the longitudinal axis of the combine harvester to spread out a surplus of threshed material in a particular area of the combine harvester. However each divider is causing an accumulation of material along its surface such that the crop mixture is still delivered in heaps to the sieves. Different crop conditions will also require readjustment of the orientation of the deflectors for continued optimum delivery of the threshed and separated material to the sieves.
It is also known to provide guide plates or baffles between the threshing concaves and the grain pan to improve the distribution of the threshed crop material falling onto the cleaning arrangement. However when there is a major unbalance between different sections of the threshing mechanism, the guide plates have to be set at steep angles, making the system prone to plugging of the concaves.
SUMMARY OF THE INVENTION
It therefore is an object of the present invention to provide an effective and reliable system for improving the distribution of threshed crop material at the rear end of the grain pan.
According to the invention there is provided an agricultural harvesting machine, comprising a threshing and separating mechanism for threshing and separating crop material; and a cleaning means for cleaning the threshed and separated crop material. The cleaning means comprising:
a grain pan means for receiving threshed and separated crop material and transporting the latter rearwardly;
a sieve means installed behind said grain pan means and operable to receive the material from said grain pan means and move it through and along; and
a fan means, operable to cause an air flow through said sieve means for lifting up discardable part from the crop material and transporting it out of the combine harvester.
The harvesting machine being characterized in that at least one portion of said grain pan means is inclined in a sideways direction for sideways movement of a portion of said threshed and separated crop material while it is being transported rearwardly towards said sieve means.
When the grain pan means comprise means for varying the inclination for adjusting the inclination angle thereof, the path of the threshed crop material can be adapted to the actual distribution of the material from the threshing mechanism. A higher setting may be required for small grains such as wheat at a lower setting for larger grains such as corn kernels. Advantageously this adjustment of the inclination can be linked to the adjustment of the threshing mechanism for the different crops.
The number of inclined sections preferably is equal to the number of threshing rotors and concaves, so two inclined grain pan portions are proposed for a twin rotor axial flow combine harvester.
When the overload is concentrated in one narrow area of the grain pan, it may be advantageous to provide substantially horizontal grain pan sections adjacent the inclined portions. Thereby the sideways movement of the crop material is stopped after the heaps in the narrow area are spread out. This avoids accumulation of material at the edges of the inclined portions. The length of these portions should be at least equal to the length of the threshing rotor and concave disposed thereabove and more advantageously to the length of the concave section through which most of the material is provided to the grain pan means.
The inclined area may then constitute a rectangular, a trapezoidal or a triangular surface. In the latter case one can dispose of a fill plate at the rear end of the inclined grain pan portions.
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Dhont André G. J.
Gryspeerdt José G. T.
Jonckheere Marc R. M.
Van Queckelberge Eric P. J.
Miller Larry W.
New Holland North America Inc.
Petravick Meredith C.
Stader John William
Will Thomas B.
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