Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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This invention relates to a seed drill having disc
shares which are mounted rotatably in holders arranged to
move in a vertical plane, the individual share discs being at
an acute angle to the direction of travel.
A seed drill of this kind is already known from
German OS 19 36 685. In this seed drill, the discs shares
each consist of two discs spaced laterally from each other,
behind which are arranged rotatably mounted pressure rollers
which close the seed furrows produced by the individual share
discs.
In spite of this arrangement, the known seed drill
has the disadvantage that the seed furrows are often not
closed in such a manner that all of the seeds placed in the
furrows receive a covering of soil enough to ensure uniform
germination. This is attributable to the fact that, especially
at high operating speeds or when the soil is very wet, soil
coming into contact with the outside of the share discs, which
` are at an angle to the direction of travel, is lifted so high,
is turned over, and is slung laterally away from the furrows
in such a manner that it is at least not fully trapped by
the pressure rollers and forced back into the open furrows.
As a result of this, seeds placed in these furrows are not
adequately covered. In areas of low rain~all where the furrows
dry out, the seeds lack the soil cover required for growth
and large crop losses are unavoidable.
Especially where so-called direct sowing is used,
as in countries where the rainfall is low, for which the known
seed drill is intended, another disadvantage arises. When this
method is used, it is customary, in order to achieve satis-
factory growth of the seed, to kill off any vegetation, re-
maining in the untilled fields from the previous crop, by
means of herbicides, either just before seeding or just before
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the seeds start to sprout. If damage is to be avoided, these
chemicals must not come into contact with the seeds. Now,
since the earth is lifted by the share discs and turned over,
if the herbicide is applied before seeding, the vegetation
carrying it thus rests face down upon the soil or in the
furrows, some of it being pressed by the rollers onto the
seeds placed in the furrows. In this way, large quantities
of herbicide may be spread over the area containing the seeds,
so that the seedlings inevitably come into contact therewith
and their development is at least considerably impaired.
If, however, the herbicide is applied after seeding,
just before the seed starts to sprout, in order to kill off
also the weeds arising from the weed seeds disturbed by the
share discs during seeding, it is impossible to prevent seeds,
lying uncovered in the inadequately closed seed furrows, from
coming into direct con-tact with the herbicide. This again
results in damage leading to reduced yields.
Another considerable disadvantage, apart from the
use of herbicides, is that the dead straw left after the pre-
ceding harvest, and any dead and also very tough parts ofvegetation which has grown since the last harvest, are forced
into the soil by the share discs. Seeds then came to rest
upon this material, so that even if the furrows are properly
closed, they cannot receive the cover required for their
growth. These disadvantages of the known seed drill lead to
greatly reduced yields, especially if there is little rainfall
during the vegetation period.
Now it is the purpose of the invention, with all of
the conditions arising during the tilling of fields and, more
particularly, when direct sowing is used, to ensure that soil
lifted by the share discs falls back unturned into the seed
furrows, after they have been seeded, thus providing adequate
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soil cover to enable the seeds to grow,
According -to the invention, this purpose is achieved
in that means for holding down the soil lifted by the share
discs, and connected to holders, are provided, the said means
each co~prising a roller, the lower part of the periphery
thereof, acting as a guide surface, being located above the
depth of penetration into the soil established for the said
share discs, and the said means extending closely adjacent the
outsides of the individual share discs running at an angle to
the direction of travel of the seed drill.
As a result of this arrangement, any soil picked up
by the share discs is lifted so slightly that it falls back
into the seed furrows, behind the discs, without turning, and
closes them. Another highly satisfactory result is that any
vegetation lying upon the ground is clamped, as it is pressed
into the soil by the share discs, between the soil lifted and
the guide surfaces of the rollers, thus springing back upwardly
" for a short distance on the back of the share discs. This
produces gaps between the pieces of vegetation, through which
the seeds can fall to the bottom of the furrows, which consist
mainly of soil, and thus acquire the desired soil cover.
Another advantage is that the said vegetation, now
located above the seeds, at least makes it more difficult for
the soil to dry out. Finally, if the said hold down means
are equipped with rollers mounted to rotate freely, it is
impossible for vegetation and clumps of earth to become jammed
between the said rollers and share discs.
The hold down means are particularly effective if
the axes of rotation of the rollers are located, as seen in
the direction of travel, after the axes of rotation of the
share discs which are mounted on the same holders.
If the rollers are adjustable in height on the
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holders, they may also act as elements restricting the depth
of penetration of the share discs into the soil. In order to
achieve satisfactory operation of the hold down means even
over extremely rocky ground, resilient elements acting towards
the ground are provided, according to the invention, between
the said rollers and holders.
For the purpose of covering seeds sown in particular-
ly wet soil, it is also desirable for the angle between the
rollers and the direction of travel, and that the between the
share discs and the direction of travel, to be different.
Since the angle between the rollers and the direction of
travel is greater than that between the share discs and the
direction of travel, under unfavourable conditions, even with
substantial amounts of vegetation lying upon the ground, not
only will pieces of this vegetation be prevented from becoming
clamped between the share discs and the rollers, but there
will also be a not inconsiderable improvement in the clamping
action of the said rollers upon the pieces of vegetation.
Finally, the holders comprise, according to the
invention, struts running, in a manner known per se from
German OS 25 05 017, in two transverse rows lying one above
the other and at least approximately parallel with each other,
with pressure rollers, located after the share discs, being
attached thereto. This arrangement assures, even over
irregular ground, the desirable constant position of the
rollers of the hold down means and pressure rollers for
satisfactory functioning of the said hold down means and
uniform depth of penetration of the share discs.
In one aspect of the present invention, there is
provided a seed drill for use on soil having disc shares with
outer sides which shares are mounted rotatably in holders
arranged to move in a vertical plane, the individual share
discs being at an acute angle to the direction
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of travel, characterized in that means, for holding down the
soil lifted by the share discs, and connected to holders, are
provided, the said means each comprising a roller, the lower
part of the periphery thereof, acting as a guide surface,
being located above the depth of penetration into the soil
established for the said share discs, and the said means being
arranged close to the outer sides of the said share discs
which run at an angle to the direction of travel.
In a further aspect of the present invention, there
1~ - is provided a drill plough with disc-shares which are mounted
to rotate in holders arranged to move in a vertical plane,
the share-discs whereof, arranged at a distance from each
other, form an acute angle to the direction of travel, while
the depth of penetration, into the ground, of the depth-
guidance elements, arranged behind the said share-discs, is
~adjustable, characterized in that hold-down devices, connected
to the holders are provided for the clods of earth lifted by
the share-discs, each of the said hold down devices com-
prising a roller the~lower part of the circumference of which,
acting as a guiding surface, is located above the depth of
penetration into the ground provided for the said share-
discs and is arranged close to the outer side of the in-
dividual share-discs, which are arranged at an angle to the
direction of travel; in that the axes of rotation of the
rollers are located, as seen in the direction of travel,
behind the axes of rotation~of the share-discs on the same
; holders, and in that the angles ~o~,~ ), between the rollers
and share-discs and the direction of travel are different,
the angle ( ~ ) of the rollers being larger than the angle
: 30 (~ ) of the share-discs.
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The invention is explained hereinafter in greater
detail, in conjunction with the drawing attached hereto, and
which illustrate the invention by way of example wherein:
Fig. 1 is a partial side elevation, in longitudinal
section, of a seed drill according to the invention,
Fig. 2 is a section along the line II-II in Fig. 1,
showing the arrangement of two share discs.
The seed drill comprises a frame 1 upon which is
arranged a number of holders 2 designed in the form of parallel-
ograms and adapted to move in a vertical plane~ Each of these
holders has two upper and two lower struts 3,4 running parallel
with each other, the front ends of which are secured pivotably
to the said frame by means of pins 5, while the rear ends
thereof are secured pivotably to holder part 7 by means of
pins 6. Located below holder part 7 is a longitudinal carrier
8 with a disc share 9 mounted rotatably at the front end
thereof. Share disc 9 consists of two disc shares 10 which
are arranged in the shape of a V in relation to each other
and are at an acute angle ~ to the direction of travel indi-
cated by arrow 11. Moreover, the distance A between the centres
of the said share discs corresponds to the distances between
the rows of seeds to be sown.
A hold down means 12 is provided on holder part 7
for each share di=c 10, the =aid mean= compri=ing a tubular
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part 13 which is displaceable in a bearing tube 14 connected
rigidly to holder part 7 and which can be locked at different
heights by means of eye bolts 15. Arranged displaceably in
tubular part 13 is a guide rod 16, the upper end of which
carries a disc shaped stop 17, while a bent shaft 18 is welded
to the lower end. Mounted rotatably at the free end of this
shaft is a roller 19 which is located close to outer side 20,
running at an angle to the direction of travel 11, of share
disc 10, forming with the said direction of travel an angle of
incidence ~ which is somewhat larger than angle of incidence
of share disc 10. Furthermore, axes of rotation 21 of rollers
19 are located, as seen in the direction of travel 11, behind
axes of rotation 22 of share discs 10.
Arranged on each guide rod 16, between shaft 18 and
tubular part 13, is a resilient element 23 in the form of a
compression spring acting in the direction of the ground 24,
allowing rollers 19 to pass resiliently over any obstacles on
the ground. Finally, each roller 19 is in a position in which
the lower part of outer periphery 26 thereof, which acts as a
guide surface 25, is above the depth of penetration into the
90il required for share discs 10.
The depth of penetration of disc shares 9 into the
soil is determined by pressure rollers 27, one of which is
arranged rotatably, behind each share disc 10, upon longitudinal
carrier 8. The depth of penetration may be varied by means of
adjusting spindle 28 secured to frame 1, by means of which
pins 5 in upper struts 3 may be pivoted towards or against the
direction of travel 11. This causes holder part 7 to pivot,
thus changing the height of pressure rollers 27 in relation
~ 30 to share discs 10.
As shown in Fig. 1, when the machine is in operation,
seed in storage tank 29 is fed in adjustable quantities,
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through metering mechanism 30 and hose 31, to share discs 10.
Individual seeds 32 drop thence into furrows 33 produced by
share discs 10. Earth 34, displaced laterally and carried
along upwardly by the said share discs as the furrows are
produced, with pieces of vegetation 35, comes under rollers
19 and is thus prevented from turning, Thus when this earth
falls back into seed furrows 23, vegetation 35 lies above
seeds 32.
