Note: Descriptions are shown in the official language in which they were submitted.
CA 02933063 2016-06-15
ROUND BALER HAVING A SENSOR FOR DETECTING THE BALE SIZE
The invention relates to a round baler having a bale compression chamber, a
roller, which is
supported against the frame of the round baler so as to be rotatable and,
during the
formation of the bale, so as to be otherwise essentially stationary and which
directly or
indirectly interacts with the bale, and a sensor for detecting the size of a
bale forming in the
bale compression chamber.
Background
Round balers are used for producing bales from stalk-shaped agricultural crop.
Such round
balers comprise a bale compression chamber and associated compression means.
After a
bale has been formed and, if necessary, wrapped with net, yarn, or a film,
said bale is
ejected backward out of the bale compression chamber.
Round balers are usually equipped with sensors for detecting the size of the
bale in the bale
compression chamber. These sensors are used for detecting whether the bale has
already
reached a specified size and the bale formation process should therefore be
terminated,
and/or for detecting the lateral distribution of the crop in the bale
compression chamber in
order to ensure, by means of suitable steering measures, which can be carried
out manually
by the operator of a towing vehicle or via an automated system, that the bale
compression
chamber is sufficiently uniformly filled across its width, since, as a rule,
the picked-up swath
is narrower than the bale compression chamber. For the detection of the
lateral distribution
of the crop in the bale compression chamber, at least two sensors, which are
disposed next
to one another, should be provided in order to detect the size of the bale at
laterally spaced
points of the bale compression chamber.
In the prior art, the size of the bale is detected by means of sensors
interacting directly with
the bale so as to have contact therewith (US 2008/00871777 Al) or so as not to
have
contact therewith (DE 10 2004 042 740 Al), or the tension in belts surrounding
the bale
compression chamber is detected in that the position of spring-loaded rolls
resting against
the belt is detected (US 4 850 271), or the position of spring-loaded idler
pulleys of the belt
is detected using potentiometers or contactlessly (US 4 924 405 A, EP 2 698
055 Al).
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Summary
The previous sensors require either relatively expensive, contactlessly
operating sensors or
mechanical sensors for detecting the position of a roll resting against the
belt or an idler
pulley of the belt, which must be calibrated in a complex manner during the
production of the
baler.
The problem addressed by the invention is considered to be that of providing a
round baler
in which the aforementioned disadvantages are not present or are present to a
reduced
extent.
A round baler is equipped with a bale compression chamber, a roller, which is
supported
against the frame of the round baler so as to be rotatable and, during the
formation of the
bale, so as to be otherwise essentially stationary and which directly or
indirectly interacts
with the bale, and a sensor for detecting the size of a bale forming in the
bale compression
chamber. The sensor is configured for detecting the supporting force with
which the roller
bears against the frame.
In other words, the sensor detects the force with which a roller, which is
rotatable but
otherwise essentially stationary during the formation of the bale, bears
against the frame of
the round baler. Since the roller interacts directly or indirectly with the
bale formed in the
bale compression chamber (in the first case, the bale rests against the roller
and, in the
second case, an endless compression means interacting with the bale, in
particular, rests
against the roller or partially surrounds said roller), the supporting force
of the roller depends
on the size of a bale that is currently being formed in the bale compression
chamber. Such a
supporting force can be relatively easily detected using inexpensive sensors,
such as strain
gauges, load cells, piezoelectric sensors, or the like. In this manner, a
sensor system for
detecting the size of a bale in the bale formation chamber is obtained, which
sensor system
is inexpensively designed and can be calibrated in a non-complicated manner
during
production. The output signal of the sensor indicates the size of the bale,
which, in turn, can
be displayed to the operator of a towing vehicle of the baler and can be used
for controlling
functions of the round baler, in particular for stopping the towing vehicle,
initiating a
wrapping process, and ejecting the bale.
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In particular, one sensor is assigned to each of the two ends of the roller
for the purpose of
detecting the lateral distribution of the crop in the bale compression
chamber. The signals of
the sensors can be displayed to the operator so that he can steer the towing
vehicle and the
baler across the field in the sense of forming a cylindrical bale, or said
signals can be used
by an automatic steering system in the aforementioned sense.
In one possible embodiment, the roller is mounted on a swivellable holder,
which is
preloaded by the force of a spring, while the spring acts on the holder and
the roller in the
sense of tensioning the compression means, and the sensor is configured for
detecting the
force with which the holder bears against a stop, which is connected to the
frame and
against which the tensile force of the compression means pulls the holder.
In another embodiment, the roller is supported against a swivelling part,
which can be
rotated between a bale formation position and a bale ejection position, while
the swivelling
part, in the bale formation position, can be coupled to the frame by means of
a locking bar,
and the sensor is configured for detecting the force transmitted by the
locking bar.
Exemplary Embodiments
Three exemplary embodiments of the invention, which are described in greater
detail in the
following, are depicted in the drawings, wherein the reference numbers should
not be used
to arrive at a restricting interpretation of the claims. In the drawings:
Figure 1 shows a schematic side view of a first embodiment of a round
baler,
Figure 2 shows a schematic side view of a second embodiment of a round
baler, and
Figure 3 shows a schematic side view of a third embodiment of a round
baler.
Figure 1 shows a schematic side view of a round baler 10, which comprises a
frame 12,
which is supported on wheels 14 and can be drawn by means of a drawbar 82 by a
non-
illustrated towing vehicle across a field in its forward direction, which
extends toward the left
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in Figure 1, in order to gather crop by means of a lifter, which is not shown,
and convey said
crop via an inlet channel 20 into a bale compression chamber 16 in which a
bale 18 is then
successively formed. The bale compression chamber 16 is delimited by rollers
22, 24, 26,
which are rotatably mounted in the frame 12 and are adjacent to the inlet
channel 20. In
addition, the bale compression chamber 16 is delimited by an endless
compression means
64 in the form of one or more belts, which are disposed laterally next to one
another and
partially surround the further roller or rollers 28, 30, 32, 34, 36, 38, 40,
42, 62 and 44 as well
as the roller 22, of which one, multiple, or all are rotationally driven
during the formation of a
bale 18. The rollers 28, 30, 38, 40 and 22 are rotatably mounted in the frame
12, i.e., apart
from their rotation about the longitudinal axis, they do not move with respect
to the frame 12
when a bale 18 is formed.
Each of the rollers 32 and 36 is mounted at their two ends on a support 50,
which is
articulated at its upper end on the frame 12 so as to be swivellable about an
axle 74. The
support 50 is rigidly coupled to one arm 52, which is preloaded by means of a
hydraulic
cylinder 54. The support 50 therefore moves upward during the formation of a
bale 18
against a set pressure, which is present in the piston rod chamber of the
hydraulic cylinder
54, when a bale 18 forms and the bale compression chamber 16 thereby becomes
larger
and larger in that the compression means 64, which delimit the bale
compression chamber
16 toward the top and the rear, deflect to an ever-increasing extent, as
indicated in Figure 1
with dashed lines.
The rollers 42, 62 and 42 are fastened on a swivelling part 46, which can be
swivelled
backward and upward about an upper axle 76 by means of an actuator 48 in the
form of a
hydraulic cylinder, in order to eject a bale 18 out of the bale compression
chamber 16. The
bale 18 then rolls on an unloading ramp 78 onto the ground.
The roller 34 is fastened on a holder 58, which is centrally articulated on
the frame 12 so as
to be swivellable about an axle 56, and is preloaded by a spring 60. The
spring 60 tends to
load the compression means 64 in that it pulls the roller 34 upward, in the
counterclockwise
direction. In the normal bale formation operation, the holder 58 rests on a
stop 68 and
moves out of its position shown in Figure 1, in the counterclockwise
direction, only when the
range of motion of the support 50 is insufficient to hold the compression
means 64 taut,
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which is possible only after a finished bale 18 has been ejected and the
formation of a new
bale 18 has begun. The round baler 10 is per se known essentially from EP 1
396 187 Al
and EP 1 364 574 A1.
A sensor 66 is used for detecting the size of a bale 18, which sensor detects
the force with
which the holder 58 rests on the stop 68. This force depends on the tensile
force in the
compression means 64, which, in turn, depends on the size of the bale 18. The
sensor 66 is
designed, in particular, in the form of a strain gauge or a load cell. The
sensor 66 is
connected to an evaluation circuit 70, which is preferably additionally
connected to a further
sensor 66 on the other side of the round baler 10. On the other side of the
round baler 10
are located, in addition, a further holder 58, a further stop 68, and a
further spring 60, which
are independent of the components (holder 58, stop 68, and spring 60) shown in
Figure 1
and therefore can move independently thereof, and so, in the case of non-
cylindrical bales
18, different values are detected by the two sensors 66. The output values of
the sensors 66
are transmitted via the evaluation circuit 70 to a display device 72, which
can be located, in
particular, in the cab of the towing vehicle. A bus line 80, in particular, is
utilized for this
purpose. The operator therefore recognizes the shape of the bale 72 on the
display device
72 on the basis of two bar graphs or any other type of depiction and, if the
bars are not the
same size, he can take countermeasures in order to form a cylindrical bale.
This task can
also be performed by an automated system. The evaluation circuit can also
control the
automated system in order to stop the towing vehicle when a bale 18 has
reached a
specified size, and to wrap said bale with net, film, or yarn, and finally
eject it. Reference is
made in this regard to EP 1 813 146 A2.
In addition, the signal of the sensor 66 or the sensors 66 can be used for
detecting an
overload of the round baler 10. If the output signal of the sensor 66
therefore indicates that a
threshold value is exceeded, which threshold value corresponds to a maximum
tensile force
in the compression means 64, a warning message can be provided to the operator
via the
display device 72, and/or the pressure in the piston rod chamber of the
hydraulic cylinder 54
and, therefore, the tension in the compression means 64 is automatically
reduced. A
proportional control valve (not shown) can be suitably controlled for this
purpose.
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In the embodiment according to Figure 2, the swivelling part 46 can be locked
on the frame
12 by means of a locking bar 84. The locking bar 84, at its front end, is
articulated on the
frame 12 about an axle 86 and encloses a pin 88 connected to the swivelling
part 46. An
actuator, which is not shown, is used for pulling the locking bar 84 downward
out of its
position that is assumed when a bale 18 is formed and that is shown in Figure
2 before the
swivelling part 46 is swivelled by the actuator 48 about the axle 76 in order
to eject a
finished bale 18. The locking bar 84 of the embodiment according to Figure 2
can also be
used in the embodiments according to Figures 1 and 3. The locking bar 84
relieves the
stress on the actuator 48 during the formation of the bale 18. There is no
stress on the
actuator 48 during this time.
In the embodiment according to Figure 2, a sensor 66' detects the force
transmitted by the
locking bar 84. The sensor 66' can likewise be designed in the form of a
strain gauge or a
load cell. Preferably, two locking bars 84 and associated sensors 66' are
provided on both
sides of the round baler 10 and are both connected to the evaluation circuit
70.
The design and the mode of operation of the round baler 10 according to Figure
2 are
identical to the round baler 10 according to Figure 1. The sensors 66' detect
the force in the
locking bar 84. This force depends on the tensile force in the compression
means 64, which,
in turn, depends on the size of the bale 18. The tensile force in the
compression means 64
propagates via the roller 44, the swivelling part 46, and the locking bar 84
to the frame 12.
The signals of the sensors 66' are used in the manner described above with
respect to
Figure 1.
In the embodiment according to Figure 3, the sensor 66" detects the force with
which the
axle or the shaft 90 of the roller 24 disposed above the inlet channel 20
bears against the
frame 12. Analogously, the sensor 66" could also be configured for detecting
the force with
which the axle or the shaft of the roller 22 or 26 bears against the frame 12.
The sensor 66"
can likewise be designed in the form of a strain gauge or a load cell.
Preferably, two sensors
66" are provided on both sides of the round baler 10 and are both connected to
the
evaluation circuit 70.
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The design and the mode of operation of the round baler 10 according to Figure
3 are
identical to the round baler 10 according to Figure 1. The sensors 66" detect
the supporting
force of the roller 24, which, in turn, depends on the size of the bale 18.
The signals of the
sensors 66" are used in the manner described above with respect to Figure 1.
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