Harvesters – Motorized harvester – With condition-responsive operation
Reexamination Certificate
2002-12-18
2004-11-09
Pezzuto, Robert E. (Department: 3671)
Harvesters
Motorized harvester
With condition-responsive operation
C056S208000
Reexamination Certificate
active
06813873
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns a device for ground copying for front attachments to harvesting machines, especially for self-propelled combine harvesters and forage choppers, in accordance with the features in the generic terms of claim
1
.
Such devices for ground copying serve to adjust the front attachments to the unevenness of the ground, so that the crop can be harvested without loss even under these conditions. For this it is adequately known to fix the attachments to the harvesting machine so that they can swivel, so that on the one hand the so-called longitudinal movement of copying can be executed along the axis transverse to the direction of travel of the machine and on the other hand transverse copying can be effected along an axis pointing in the direction of travel. The cases for the application of such devices for ground copying extend to cutting and mowing machines of all types of construction and to gathering devices on the most varied types of harvesting machines. Therefore they have become so important, as all these attachments must have an appropriately wide working width because of the very high productive capacity of the present-day harvesting machines. In the state of the art a multitude of variant embodiments for this have already become known, which can be divided into two large categories.
The first category is described in EP 0 331 893 B1, in which the attachment is fixed on the front side of the harvesting machine so that it can tilt for the purpose of copying longitudinally and transversely. Two hydraulic cylinders arranged at a distance from each other and symmetrically about the central longitudinal axis of the harvesting machine support the attachment from below with a force such that is presses on the ground only with a residual weight and consequently with a slight pressure, in order to be able to follow the irregularities of the ground via skates, running wheels or its ground trough itself for longitudinal copying. For keeping to a set value for the ground pressure either by means of suitable sensors, the pressure in the hydraulic cylinders or the supporting force of the hydraulic cylinders on the chassis of the harvesting machine is monitored. In the event of a deviation from this set value the piston rods of the hydraulic cylinders are driven so far in or out until the set value again prevails, which is associated with a raising or lowering of the attachment. For transverse copying the attachment is equipped in its outer side regions with sprung elastic slide hoops, which detect the ground and via a potentiometer connected to them furnish a measure of the distance of the attachment from the ground. If the signals from both sides differ from each other, two further hydraulic cylinders have pressure applied to them, which are applied in a vertical direction between for example the feeder shaft of the combine harvester and the attachment, which tilt the attachment laterally until on both sides of the attachment the same distance is restored again.
Such devices for ground copying serve to adjust the front attachments to the unevenness of the ground, so that the crop can be harvested without loss even under these conditions. For this it is adequately known to fix the attachments to the harvesting machine so that they can swivel, so that on the one hand the so-called longitudinal movement of copying can be executed along the axis transverse to the direction of travel of the machine and on the other hand transverse copying can be effected along an axis pointing in the direction of travel. The cases for the application of such devices for ground copying extend to cutting and mowing machines of all types of construction and to gathering devices on the most varied types of harvesting machines. Therefore they have become so important, as all these attachments must have an appropriately wide working width because of the very high productive capacity of the present-day harvesting machines. In the state of the art a multitude of variant embodiments for this have already become known, which can be divided into two large categories.
As regards this device for ground copying, it can be criticized on the one hand since because of the constantly flowing hydraulic oil it reacts to a considerable degree much too sluggishly. On the other hand it delivers the control signal for longitudinal copying much too late. Furthermore there is a disadvantage that through ground detection under different weather conditions, through constantly changing leverage ratios and hysteresis phenomena in the lifting system and through the influence of markedly fluctuating dynamic forces, practically no reproducible set values for ground pressure can be realized. The consequence of this is that obstacles cannot be avoided and its operability is put into question even at moderate driving speeds.
The second category of devices for ground copying, one embodiment of which is described in EP 0 748 153 B1, works alongside the facility proposed in the first category via direct ground contact of the attachment now principally without this. For this, ultrasound sensors are fixed on both sides in the region of its sidewalls, which continuously measure the distance of the attachment from the ground and produce a corresponding output signal. In the driver's cab of this harvester a control device is installed, which receives the output signals from the ultrasound sensors and in the event of a deviation from a prescribed set value for the distance it addresses a control valve in the hydraulic circuit of the hydraulic cylinder for raising and lowering the attachment. Since the hydraulic cylinder is arranged analogously to the solution described in the foregoing and is actuated likewise, this system operates just as sluggishly and imprecisely as regards adherence to the set value for the distance between the attachment and the ground. The ultrasound sensors present an additional disturbing factor, as they cannot distinguish between plants or stubble lying on the ground and the ground itself, so that under these conditions they deliver false distances. Because of their arrangement just above the ground, these errors are made especially noticeable. Furthermore, ultrasound sensors react to wind and humidity with a large scattering of the measured values. In addition they are relatively expensive to purchase, so that all these disadvantages taken together could be the reason that such a device for ground copying has not been accepted in practice.
Setting out from the negative experiences from the afore-described solution, a further device for ground copying has been published in EP 0 511 768 B1 and EP 0 936 475 A1, where the ultrasound sensors employed there are fixed far above the ground and in the side region of the attachments. With this it is achieved that only the measurement error for distance caused by stubble or plants lying on the ground is diminished somewhat as a percentage.
A further possibility for a device for ground copying be means of ultrasound sensors is described in EP 0 765 594 A1 with an example of a combine harvester cutter. There the ultrasound sensors measure continuously the distance to the sensor skids attached to the exterior of the cutter with the aid of a plate attached to them, in order to exclude the error from ground sensing. However this measure alone is not sufficient for well-functioning ground copying. Furthermore, the angle of incidence and emission to the plate varies constantly, so that distortions to the measurement of distance occur.
To be assessed analogously is the ground copying in accordance with DE 196 01 420 A1, where a prestressed sliding element of narrow spring steel senses the ground and transmits its movement in consequence of ground irregularities to a signal transmission element. This is formed as a parallelogram of rods, to which a plate is attached, which in contrast to the previously described plate on the sensor skid executes approximately parallel movements. This is irradiated by a wave sensor and reflects its radiation.
Allwörden Wilhelm von
Mende Ingo
Scholtke Henri
Spaida Gisela
Spaida Peter
CNH America LLC
Henkel Rebecca
Maurer Brant T.
Pezzuto Robert E.
Spaida Gisela
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