Weighing scales – Structural installation – Vehicle
Reexamination Certificate
1999-08-03
2001-06-19
Gibson, Randy W. (Department: 2859)
Weighing scales
Structural installation
Vehicle
C177S145000, C702S050000
Reexamination Certificate
active
06248963
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a baler. More particularly this invention concerns a system for measuring the density of bales produced by a baler.
BACKGROUND OF THE INVENTION
Straw is particularly useful as animal bedding, horticultural mulch, and for industrial and commercial purposes such as in insulation and packing materials. Straw is produced by cutting standing crop and, normally after stripping off any useful part, spreading it on the field to dry for some time. Hay is the more useful part of the standing crop that is similarly cut and dried in the field, but that is subsequently used as animal fodder or ensilage.
In order to turn the loose straw or hay into a product that can be transported, stored, and accounted for, it is pressed into bales. For commercial purposes the so-called large-format square bale, which is actually parallepipedal, is used. It is produced in a baler that picks the cut crop up off the ground, normally comminutes it somewhat, presses it into bales, applies ties around the bales, and drops the bales on the field behind the machine. In view of the pace of the baling operation, it is normally more expedient for the baler simply to leave a trail of bales in the field that are later picked up by a different crew operating at a different pace.
Ideally, all of the bales produced should be of the same size and weight. The size is determined by the bale length, width, and height. The width and height are established by the size of the pressing passage and the length by the cycling time of the tying device of the baler. The weight is clearly a function of size, and also of the density of the bale, that is how tightly or loosely the straw or hay is packed in it.
The press passage typically has side walls that can be moved horizontally by hydraulic actuators to narrow or widen the width of this passage. Since the downstream end of the passage is always open, it is the friction with the sides of the passage that determines how much pressure resists the piston that packs wads of the straw or hay against the trailing end of the strand that is subdivided by the tying device into bales while still in the passage. Thus as the passage narrows, the friction increases as does the density of the bale and in fact it is the relative spacing of these side walls that is a principal factor, along with the consistency of the material being baled, in the density of the bales being produced.
German 38 20 367 describes a large-format square baler that picks the crop off the ground and packs it in a press passage in which a piston is reciprocated by a crank drive driven from a tractor power takeoff. The drive is supported at its upper side on a beam that is fixed on the side walls of the pressing passage. The rear end of the pressing passage is as described above formed by pivotal wall panels whose spacing can be changed hydraulically. The front wall of the pressing passage carries an inductive position sensor spaced closely to the beam so that its output indicates the amount of bend in this beam which is generally proportional to the force being exerted by the piston. This output is amplified and fed to a threshold discriminator. The output of the amplifier is smoothed and fed to an adding circuit and there compared to a set point. The position of the side-wall panels is adjusted in accordance with the difference.
Such an arrangement makes it possible to maintain the pressing force generally constant but does not really provide a readout of the actual density of the bales being produced. This density is affected by many factors, including the piston force, the composition of the material being baled, the moisture content of the material being baled, and the friction of the walls of the press passage.
European 0,223,350 and 0,223,351 describe an improvement on the system of DE 38 20 367. Here the crank drive for the pressing piston has a pair of piston rods that are each mounted at on end on the crank on the output shaft of the main drive and at the other end on bolts on the pressing piston. These bolts are provided with shear-force sensors in an annular array or with bend-type strain gauges. Thus the pressing force is measured directly, but as mentioned above this is only a factor in the bale's density and does not provide the equipment operator with an exact readout of bale density.
Finally, German 27 34 766 describes another large-format square baler wherein a pivotal side wall of the pressing passage is associated with a sensor and is urged into the passage so that its deflection is a measure of the compaction in the passage. This system is used with a set-point system as above to establish a standard compaction, but still does not give the operator of the machine a display or readout of the densities of the bales being produced.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to provide an improved baling system.
Another object is the provision of such an improved baling system which overcomes the above-given disadvantages, that is which automatically determines the exact density of each bale as it is produced, and that allows this density to be stored, displayed, and/or used to control the system.
SUMMARY OF THE INVENTION
Bales are produced by a baler having a pressing passage of predetermined cross section and from which emerges a succession of the bales that travel rearward from the press passage over an output guide and fall off a rear edge of the guide from the baler. The density of these bales is determined according to the invention by weighing each of the bales in the guide and producing a weight output corresponding to a weight of the bale in the guide and measuring the length of each of the bales in the guide and producing a length output corresponding to a length of the bale in the guide. Then the volume of each of the bales is calculated by multiplying the respective bale length output by an area equal to the cross section of the passage and each calculated volume is divided by the respective weight output to derive the density of the respective bale.
It is a relatively simple matter to continuously determine the bale densities in this manner by standard computer means. The length output Lx is multiplied by the cross-sectional area of the passage to produce a volume Vx which is then divided by the weight Gx for the bale, producing a density &zgr;x for the bale in question. The density will be very exact and will allow the machine operator, if necessary, to adjust the baler to produce bales of different length and/or density while the machine is working. For instance if it is determined that the bales are too dense, the operator can decrease bale length by decreasing the cycle time of the tying device or can reduce back pressure on the bales by increasing the width of the pressing passage. Furthermore the computer can be connected to a level detector which compensates for any nonvertical position of the baler.
According to the invention the derived densities are averaged and displayed for a plurality of bales. Alternately the derived densities are averaged only over a predetermined limited time period.
The bale weight outputs are produced according to the invention by continuously monitoring the downward force with which the bales bear on the guide rear edge, continuously calculating an average of the monitored force, and establishing as a bale weight output the calculated average each time the calculated average peaks before the respective bale drops from the guide rear edge. The bale length outputs are produced by rotating a movable sensor element on the guide displaceable by the bales passing therealong and converting movement of the sensor element into an output corresponding to the respective length output of a bale passing thereover.
Both of these measurements can be made at the rear edge of the guide. Thus as the bale reaches a point where its center of mass is above or slightly rearward of the rear guide edge, the bale will tip up and its full weight will bear on the rear guide portion, so that t
Case Harvesting Systems GmbH
Dubno Herbert
Gibson Randy W.
Wilford Andrew
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