Harvesters – Motorized harvester – With condition-responsive operation
Reexamination Certificate
2001-05-08
2003-04-15
Will, Thomas B. (Department: 3671)
Harvesters
Motorized harvester
With condition-responsive operation
C701S050000
Reexamination Certificate
active
06546705
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for controlling an agricultural baling machine when combined with and connected to a tractor and, more particularly, to a method and apparatus for maximizing the work output of a baler by maximizing the flow rate of material through the baler.
In the field of agricultural vehicles it is well known to provide a baler, that is towable behind a tractor, to gather and form into bales biological matter left after a harvesting or mowing operation. “Biological matter” as used herein includes but is not limited to straw, grass, hay, forage and silage. “Tractor” as used herein includes any vehicle capable of propelling and providing power to a baler.
A baler is in use hitched to the tractor hitch and draws power from the tractor power take off (PTO) shaft, for the purposes of gathering and compacting biological matter. The biological matter typically lies in swaths or windows in a field. The baler gathers the biological matter, typically lying over a distance of several tens of meters, into an intake at the front of the baler. The baler compacts the biological matter into a bale of predetermined shape. The baler includes mechanisms for tying the bales with strong twine and knotting the twine; and then ejecting each completed bale, as it is formed, from the rear of the baler.
A development occurred in the baler art in the late 1970's. This was the introduction of so-called “large rectangular balers”, or “large square balers”. Some known large rectangular balers are capable of producing cubical bales each weighing a ton or more. This represented a significant increase, in baling capacity, over the previously available balers.
However it is becoming increasingly common for operators to use so-called “Midi” balers that typically produce bale masses in the range 250-750 kg. The invention is particularly but not exclusively suitable for use in such Midi-balers.
During use the pre-compression chamber forming part of a rectangular baler periodically transfers biological matter to a main baling chamber. A piston, in the baling chamber, that reciprocates under power from the tractor PTO shaft, compresses the biological material into a bale whose density is dictated by numerous factors including the volume of each charge from the pre-compression chamber.
Rectangular balers operate most efficiently when the swaths of biological material through which they are towed are of constant density. This ensures that the pre-compression chamber fills at a substantially constant rate. In practical use of large rectangular balers, however, the swath density is rarely constant over an entire field, or even from place to place in a swath. This can be for a number of reasons, including variations in crop density before harvesting; and variations in efficiency of the harvesting process leaving different amounts of biological material in different parts of the swaths. Such variations in the swaths often arise when, during harvesting, a harvesting machine (typically a combine harvester) has to slow down or stop part way along a row of crop. The variations also arise at junctions between swaths, in non-rectangular fields.
Heretofore, the operator of a tractor/baler combination has had to rely on visual inspection of the swaths as the tractor approached them, in order to judge the swath density. If the operator perceived a region of low swath density he would attempt to increase the tractor forward speed to try and temporarily increase the rate of intake of biological material into the pre-compression chamber, with the aim of maintaining a generally constant throughput of biological material through the baler.
Similarly if the operator noticed a region of high density in the swath he would attempt to reduce the tractor speed by an appropriate amount.
This method of regulating the throughput of biological material is inefficient for numerous reasons, including, at least:
a lack of consistency in the remedial action taken to overcome low and high swath densities;
the possibility of overloading the tractor engine when attempting to accelerate the tractor, e.g. as a result of performing transmission shifts that are not timed correctly and hence coincide with peak PTO shaft loadings. This can have an adverse effect on the engine loading and can in any event cause the tractor to slow or stop, thereby affecting work rate;
failure to notice or respond adequately to high swath densities leading to blockages, in the pre-compression chamber, that require halting of the baling operation to clear; and
the tractor operator taking remedial action for too long or too short a period.
In sloping fields the above-noted problems are frequently more acute than in flat fields.
In general it is desirable to maximize work rate during baling operations. One reason for this is that the moisture content of the biological material frequently affects its specific mass, quality and value. It is likely that delays and inefficiencies in baling operations will allow unacceptable moisture content changes, especially in countries, such as those in Northern Europe, whose climates are variable at most times of year.
The prior art discloses several attempts at improving the consistency of the charge supplied from the pre-compression chamber to the baling chamber.
In GB-A-1.575.243 and U.S. Pat. No. 4,034,543 mechanisms temporarily halt both the baling plunger and the stuffer fork that supplies charges of biological material from the pre-compression chamber, when a mass sensor detects underloading of the said chamber.
However, U.S. Pat. No. 4,135,444 notes that the technique of GB-A-1.575.243 and U.S. Pat. No. 4,034,543 is sub-optimal because the need to accelerate and decelerate the massive plunger leads to failure of mechanical components, such as clutches, in the baler.
U.S. Pat. No. 4,135,444 proposes temporary halting of only the stuffer forks, while the plunger continues to reciprocate, until the charge in the pre-compression chamber is adequate. However there is no disclosure in U.S. Pat. No. 4,135,444 of how to accommodate swaths of high density, that lead to overloading of the pre-compression chamber and/or the tractor engine.
Also, none of the aforementioned documents discloses an apparatus or method whose aim is to maximize the overall work rate of the tractor/baler combination; nor does any of them disclose a method or apparatus that may compensate for the effects of field slope on baler throughput.
SUMMARY OF THE INVENTION
It is an object of the present invention to overcome the aforementioned disadvantages of the prior art by providing a method and apparatus for controlling the operation of a baler by monitoring the flow rate of the baler and adjusting the speed of the tractor towing the baler to optimize the crop throughput.
It is an feature of this invention to comparing the assessed flow rate against an optimal flow rate, and adjusting the tractor speed in dependence on the outcome of the comparison.
It is an advantage of this invention that the tractor speed is changed only when necessary, as determined by the assessed flow rate of biological material.
It is another object of this invention to adjust the flow rate of the baler by adjusting the tractor forward speed, both when the flow rate of material through the baler is too high and when the flow rate is too low.
It is another feature of this invention that the method of controlling the tractor/baler combination optimizes flow rate and prevents blocking of the pre-compression chamber.
It is still another object of this invention to repeat the method steps cyclically in dependence on the pulses of the clock of a microprocessor arranged to carry out the method.
It is still another feature of this invention that the correction effected by adjustment of the vehicle speed may take effect only for the duration of the sub-optimal flow rate through the baler.
It is yet another object of this invention to use transmission shifts to change the speed of the tractor thereby allowing the tractor engine to run
Lowe John Charles
Naaktgeboren Adrianus
Paquet Bert J. F.
Scarlett Andrew James
Semple David Alexander
Mammen Nathan
Miller Larry W.
New Holland North America Inc.
Stader John William
Will Thomas B.
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