Note: Descriptions are shown in the official language in which they were submitted.
CA 02266768 1999-03-24
F-6137
POTATO HARVESTING MACHINE
The invention relates to a potato harvesting machine of the introductory
portion of claim 1.
Usually, for harvesting potatoes, banks, in which the potatoes are
contained and out of the upper side of which a portion of the stems and leaves
protrudes, are picked up by equipment and supplied to a downstream screen
conveying
device, on which the topsoil surrounding the potatoes is screened.
Furthermore, in the
harvesting machine, the potatoes are separated from the stems and leaves
portion. For
this purpose, a device is provided, which removes the leaves and stems and is
disposed, for example, at the end of the screen conveying device.
It is an object of the invention to provide a potato harvesting machine,
with which the separation of the potatoes from the leaves and stems, as well
as from
the soil, is improved.
Pursuant to the invention, this objective is accomplished by the
distinguishing features of claim 1. With respect to further advantageous
developments,
reference is made to claims 2 to 12.
By placing the device for removing leaves and stems above the working
end of the screen conveying device, especially a screen conveyor belt,
effective
separation of potatoes from the stems and leavc;s is assured. The stems and
leaves
portion, which protrudes upwards out of the soil bank, is taken hold of in the
original
ground orientation of the potatoes and their stems and leaves, before the
stems and
leaves and the potatoes experience a radical change in position. At the same
time, due
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to the upwardly directed tensional movement, the potatoes are raised, as a
result of
which the screening of the soil is improved. Such a device for removing stems
and
leaves can be assigned to the front region of the screen conveyor belt, so
that the
separation of potatoes from stems and leaves can take place at an early stage.
It is particularly advantageous if the device for removing stems and
leaves is held adjustably and at a variable height above the screen conveyor
belt, as
a result of which it is possible to adapt it to the respective thickness of
the bank or
banks, which have been taken up. If there is a scanning organ for determining
the
optimum height difference between the bank picked up and the device for
removing
leaves and stems, there can be continuous adjustment during the operation.
If there is at least one flail roller for comminuting and moving along the
stems and leaves taken up, there is an additional suction effect for the stems
and
leaves, which further improves the separation of the stems and leaves portion
from the
potatoes.
Further advantages and details arise out of the example of the object of
the invention, which is described in the following and shown in the drawing,
in which
Figure 1 shows a diagrammatic side view of the potato harvesting machine,
Figure 2 shows a view of the part of Figure 1 from the rear,
Figure 3 shows a view, similar to that of Figure 2, with a screen conveyor
belt
intended for picking up two banks,
Figure 4 shows a view, similar to that of Figure 1, for which the device for
removing stems and leaves is assigned to an upper transfer station for
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the potatoes,
Figure 5 shows a view, similar to that of Figure 4, for which the device for
removing stems and leaves is assigned to a lower end of a screen
conveyor belt close to the pick-up region,
Figure 6 shows an alternative arrangement iEor a device for removing stems and
leaves, with rollers aligned parallel to the conveying direction,
Figure 7 shows a detail view of the device of Figure 6, for removing stems and
leaves, above the bank that is to be conveyed and
Figure 8 shows the part of Figure 7 in a vif;w from the rear.
In particular, the potato harvesting; machine 1 has a pick-up device 2,
which is intended for picking up one or more potato banks 3 and on which a
screen
conveying device 4 is disposed downstream, which takes over the bank or banks
picked up and conveys them further within the potato harvesting machine 1.
During
the further conveying, the potatoes 5 are screened so as to separate them
largely from
the soil 6 surrounding them. For this purpose, the screen conveying device 4
comprises a screen conveyor belt 7 or the like, the mesh width of which is
adequate
for permitting passage downwards of the soil, the potatoes 5 remaining on the
screen
conveyor belt 7. Instead of a screen conveyor belt 7, other conveyors, such as
roller
conveyors, which permit passage of the soil downwards, also come into
consideration.
Above the screen conveyor belt ?, there is a device 8 for removing
stems and leaves. This device 8 separates the potatoes 5, which are in the
soil 6, from
their upwardly protruding stems and leaves portion 9.
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The device 8 for removing stems and leaves has two rollers 11, 12,
which are aligned parallel to one another, are opposite to one another and
driven in
the direction of the arrows 10 mutually opposite to one another and which form
the
boundary of a stems and leaves entry gap 13.
In a first example, the rollers 11, 12 are disposed transversely to the
conveying direction of the harvested material. The roller 11, which is
disposed
downstream in the conveying direction, is constructed as a star wheel roller,
which has
conveying fingers protruding essentially radially outwards. Along the
periphery of the
star wheel roller 11, different deformation and displacement zones can be
formed by
different configurations of the conveying fingers. For example, one or more of
the
conveying fingers 29 can be longer than the others, in order to ensure, by
these means,
a different effect on the stems and leaves 9 and on the soil components or
stones
contained in the stems and leaves.
The front roller 12, lying opposite tlhe star wheel roller 11, is constructed
as a smooth roller and is fixed at a rocker arm 14, which is held by means of
a spring
15. As a result, the inlet gap 13 is variable with respect to its width.
Moreover, the
height h of the device 8 for removing stems and leaves can be adjusted
variably above
the bank 3, which has been picked up. The height h should be adjusted as a
function
of the thickness of the bank 3 that has been picked up, in order to obtain
optimum
separation of the stems and leaves portion 9 from the potatoes 5 and, at the
same time,
to ensure that the potatoes 5 are only raised without penetrating into the
inlet gap 13
of the device 8 for removing stems and leaves. To adjust the height, a
scanning organ
16 is assigned to the device 8 for removing stems and leaves and extends in
the
direction of the harvested material located on the screen conveyor belt 7.
When
several banks 3 are picked up, it is possible to provide several scanning
organs 16 for
the individual banks 3. The scanning organ 16 is mounted pivotably at an axis
17 and
lies with its end 18 on the harvested material. 'The swiveling angle of the
scanning
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organ 16 is measured as an electrical signal and passed over a lead 19 to a
control unit
20, which in turn triggers an adjusting organ 21, such as a hydraulic
cylinder, in order
to vary by these means the height of the device 8 for removing stems and
leaves by
swiveling about the axis 22. In the operating position, the rollers 11, 12,
which form
the boundary of the inlet gap, are kept as close as possible above the
harvested
material picked up; the distance should be less Than about 30 cm.
The stems and leaves 9 usually arc: not comminuted by the rollers 11,
12 forming the boundary of the inlet gap 13. The; conveying fingers of the
star wheel
roller 11 are also constructed flexibly in order to ensure that the stems and
leaves are
grasped completely without being separated. Above the rollers 11, 12, there is
at least
one flail roller 23 for comminuting and moving along the stems and leaves 9
that have
been picked up. The flail roller 23 rotates at about 1,000 rpm, that is, at a
speed
speed higher than that of the rollers 11, 12, which rotate at 200 to 500 rpm.
An
arrangement of several flail rollers 23 also comes into consideration. The
flails 24 are
disposed spirally offset over the axial extent 25 of the flail roller 23. This
results in
an averaging of the suction effect on the stems and leaves 9, which are to be
drawn
in, and portions of the stems and leaves 9 with long stems are also drawn into
the inlet
gap 13 optimally by these means. The flail roller 23 is disposed downstream
from a
jettisoning device 26, which is bounded on the upper side by a bordering sheet
of
metal 27 forming the boundary of a jettisoning channel and on the underside by
a
conveyor belt 28, the conveyor belt 28 ejecting the material, brought along by
the
flails 24, next to the potato harvesting machine 1. For this purpose, the
conveyor belt
28 is disposed transversely to the working end of the screen conveyor belt 7.
The device 8 for removing and leaves and stems can be disposed
variably with respect to the working end of the screen conveyor belt 7. In
Figure 4,
a placement close to an upper side transfer region of the harvested material,
which has
been picked up, is shown. In Figure 5, the device for removing stems and
leaves is
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placed close to the pick-up device 2. This arrangement has the advantage that,
by
raising the potatoes 5, there is good mixing of tlhe soil early on and, in
this respect,
the screening process in the further course of the screen conveyor belt 7 is
improved.
In a second embodiment of the invention, the rollers 11, 12 are disposed
in the longitudinal direction of the bank 3, which has been picked up (Figures
6 to 8).
Due to the fact that the flail roller 23 is also disposed longitudinally, the
ej ection duct
26 then requires no further conveyor belt and the conveyed and comminuted
stems and
leaves are ej ected directly at the side. For this arrangement, the rollers
11, 12
preferably are formed similarly to one another.
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