Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relates to a machine for the
root-pruning of plants growing in rows, such that the root
system of the plants will be small in circumference but
finely-branched, the machine having for each plant row a knife
unit with mobile knives, of which a first kni~e lies in a
vertical plane parallel to the direction of travel of the
machine, and a second knife has a substantially vertical
portion and a substantially horizontal portion.
In the nursing of plants which are later to be planted-
out at a permanent locality it is desirable, for at least
two reasons, that the root system of the plants be small in
circumference but well-developed and finely-branched. Firstly,
such a root system entails that the final planting can be
effected with a very high probability of survival for the
plants, since such a root system has a large number of fine, .
nutrient-absorhing roots of the type which, in an unpruned ~.-
root system, is primarily to be found at the peripheral portions
of the root system. Secondly, in machine-lifting of the plants,
long, unpruned roots have a tendency to become entangled in
the Iifting machine or prematurely to pull up adjacent plants ~ .
so that these cannot be grasped by the lifting members of the
machine.
. The object of the present invention is to provide .;
a machine of the type disclosed by way of introduction, the
machine being designed to carry out, rapidly and without
operational trouble, root-pruning of the plants so that the ;.
plants can develop the intended root sys.tem. -
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Accordingly~ this invention provides
a machine for the root-pruning of plants growing
in rows, such that the root system of the plants will be
small in circumference but finely-branched, the machine
having for each plant row a knife unit for forming a
groove in the ground and root~pruning the plants, each
said knife unit comprising a first and second knife, said
first knife being forward of said second knife and lying
in a vertical plane parallel to the direction of travel of
lO the machine, said second knife having a cutting blade
comprising a substantially vertical blade portion and a
substantially horizontal blade portion,said first and
second knives being rigidly interconnected and arranged for
reciprocatory movement in a direction parallel to the direc-
15 tion of travel of the machine, and a compactor disposedbehind said second knife for reclosing the groove made in
the ground by the knife unit.
The nature of the present invention and its objects
will be more readily understood from the following brief
20 description of the accompanying drawings, and discussion
relating thereto.
In the accompanying drawings:-
Fig. l is a side elevation of the machine according
to the invention;
Fig. 2 is a rear view of the machine, certain
l~ details having been omitted for greater clarity; and
Fig. 3 is a cross-sectional view of a drive
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mechanism embodying the present invention for setting the
knife support in rapid penulating motion.
As will be apparent from the drawings, the machine
! iS built up around a horizontal, transvexsely directed frame
member l from which extend forwardly two supporting brackets
2 which are connected with their forward ends to a ¢onventional
three-point hitch 3. To permit towing, the machine is connected
to a tractox by means of the tractor drawbars 5, lift rod 6
and power take-off 4. The frame member l is supported at a
definite height above the ground and laterally steered by two
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steerable front wheels 7, whose wheel forks 8 are pivotally
mounted in fastening arms 9 projecting obliquely downwardly-
forwardly from the ~rc~me member 1. A steering rod 11 is fixed
in the upper end of one fork 8, by means of which rod the
fork can be swung about a substantially vertical pivot axis.
Furthermore, the two forks 8 are interconnected by means of a
steering tie rod 10 which transfers the steering movements o the
steering rod from one fork to the other.
A number of pruning assemblies 12 is disposed behing the
transversely extending frame member 1 and fixed therein. As
is apparent from Fig. 2, the machine in the illustrated
embodiment has six identical pruning assemblies 12 and the machine
can thus root-prune six plant rows simultaneously. Naturally,
tha machine may also be provided with a different number of
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pruning assemblies,being thus designed for pruning a greater
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: or lesser number of plant rows simultaneously. ~.
One upper and one lower guide element 15 are disposed
on the rear side of the frame member 1 to facilitate fixation Of
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the pruning assemblies 12. ~hese guide elements are parallel
- with each other and with the upper and lower sides of the
frarne member, respectively. In order to permit fixation, each
pruning assembly 12 has, at its upper end, a vertical and
transversely directed fixation plate which, at its forward end,
has a horizontal guide element 16 whose dimensions are such
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that it fits in between the guide elements 15 on the rear side
of the frame member 1. The fixation plates 17 and thus, the
pruning assemblies 12 are fixedly screwed by means of screws 18
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to the transverse frame member 1. n this instance, the
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transverse frame member 1 is provided with several different
series of threaded holes which are spaced such mutual distances
apart that the pruning assembli~s 12 can be so placed in
relation to each other that they are correctly aligned with
the plant rows generally irrespective of the row spacing.
Like the pruning assemblies 12, the fastening arms 9
of the steerable front wheels 7 are disposed in such a manner
that they can be moved laterally, whereby the track gauge of
the machine is adaptable to a certain row spacing or to a
certain width of the bed in which the plants are growing. In
order to permit this change of the track gauge, the fastening
arms 9 can be anchored in the transverse frame member l in
many different ways, but they are suitably fixed to the under-
side of the frame member in the same manner as the pruning
assembli~s 12 are fixed to the rear side thereof.
As is particularly clearly apparent from Fig. 1, each
pruning assembly 12 has a vertical frame portion 14 of
U-shaped cross-section which is open rearwardly and has a
gently rounded forwardly facing bottom. The fixation plate 17
of the pruning assembly is located in the upper forwardly
facing end of the vertical frame portion 14. Two bearing
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bushings l9 are disposed in the lower end of the ver~ical
frame portion 14 on the inside, the bushings being coaxial
and their common central axis being horizontal and at right
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~ angles to the direction of travel of the machine. A journal
`~ is pivotally accommodated in these bearing bushings and is
rigidly connected to the forward end of a ~ertically adjustable,
rearwardly directed~arm 20. As a result, the arm 20 will permit
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being pivoted in a vertical plane parallel to the direction
of travel of the machine. ~n ~djustment device 21 is rigidly
fixed at the rear end of the arm 20. This adjustment device 21,
which is disposed substantially vertically, serves for vertical
adjustment of the arm 20 in relation to that wheel 23 which
supports the rear end of the arm. The wheel 23 is connected
to the adjustment device 2:L by the intermediary of a rearwardly
directed arm 24 which is anchored with its forward end in the
adjustment device such that the arm can be pivoted through a
certain angular range about a vertical axis extending through
its forward end. Because of the pivotability o the rearwardly
directed arm 24, the wheel 23 will not prevent steering of the
machine laterally. A device, located straight above the wheel
23 on the rearwardly directed arm 24, is provided for the
fixation of one or more weights 25 whose object will be
described below. The adjustment device 21 is provided internally
with a screw whlch, by means of an adjustment knob 22, realizes
vertical adjustment of the rearwardly directed arm with the
wheel 23 in relation to the arm 20.
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^ A drive mechanism 26 is disposed at the upper end of
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; the vertical frame portion l4. In this drive mechanism is
anchored a rearwardly directed connecting arm 27 which ~an be
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put in reciprocatory motion by the drive mechanism. The rear
end of the connecting arm is conhected by the intermediary of
a linkage to the upper end of knif~ support 28 which is
designed as a substantiall~y vertical rod. Furthermore, the
knife support 28 is, at a lower portion, connected by means
of a linkage 31 to the vertically adjustable arm 20 but extends
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beneath said arm and has, at its lower end, fixing means for
the knife unit 13 of the pruning assembly 12. The length
the connecting rod 27, the upper portlon of the knife support
28, the portion of the arm 20 connecting the knie support
with the vertical frame portion 14, and the distance between
the bearing bushing 19 and the drive mechanism 26 in the ver~i-
cal frame portion 14 are such that said parts together form
a parallelogram suspension for the knife uni~ 13. As a re-
sult, the knife unit 13 is movable in a vertical sense without
any change in its other orientation relative to the ground.
The adjustment of the height position of the knife unit 13
relative to the ground, that is, its cutting depth, is rea- ~`
lized by means of the adjustment knob 22~ To ensure that the
knife unit actually works at the cutting depth intended, the
rearwardly directed arm 24 is loaded with a suitable number
of weights 25 which also have the purpose of sub~ecting the
wheel 23 running straight above the`groove in the ground,
which has been produced by the knife unit 13, to such a load
that the groove in the ground is closed, whereby water loss
and desiccation of the portions of the soil adjacent to the
groove are avoided.
As is particularly clearly apparent from Fig. 1, the
kr:ife unit 13 comprises a first or leading knife 29 and a rear
or main knife 30. Both of these knives are secured by dovetail
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- fastenings in the lower end of the knife support 28 and locked
in their positions by means of screws. By this design of the
fastening of the knives a rapid and simple exchange is possible,
if need be. As the dovetail fastening for the leading knife 29
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is transversely directed, there is a certain possibility of
adjusting the leading knife 29 laterally in relation to the
mair~ knife 30. The leadLng knife 29 is ~lanar and has a
straight edge which commences above the soil surface and
makes an acute angle with said surface. The rear lower end
of the edge of the leading knife lies at a certain depth ~ ,
beneath the soil surface (20-60 mm~ and,as is a~parent from
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`~ Fig. 2,runs ~traight in front of the u~er portion of the
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' main knife 30. As is apparent fr,om Fig. 1, the main knife ,
30 is elongated and dixected as an extension of the knife ~ -,
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support 28, that is, substantially at right angles to the
',~ soil surface. The edge of the main knife 30 has an upDer ver-
,,~ tical portion and a lower, gently curved portion which ends
' substantially straight beneath the plant row to be ~runed.
, Moreover, the main knife is of such a length that the cutting "
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', depth for the lower portion of its edge normally lies at
60-120 mm. The lower portion of the main knife 30 further
"',~ slightly tapers at the front edge 50 that its edge as viewed
, from~above will in some degree incline to the transverse di-,
rection of the machine; whereby the lower knife end which is
; bent inwardly'beneath the plant row will lie slightly rear-
"~ wardly of the upper knife portion which is located straight
', to the rear of the leading knife. Moreover, the main knife
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' is slightly twisted at least along the gently curve ~ortion, ~ .
whereby the rear edge of that portion of the k~ife whioh
extends inwardly~beneath the plant row will ~e situated a
~ slightly lesser distance beneath the soil surface than its
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~ . edge. This twist or clearance of the lower portion of the
1(~87~5~
main knife is clearly apparent in Fig. 1 wher~ the cl~arance
angle is designated u and can suitably amount to a value less
than 10. The above described design of the main knife is
specially suited for preventing plant portions getting stuck
thereto. The leading knife 29 has for its object to cut off
such plant portions as are located above the soil surface or
immediately beneath it and to provide a groove in which the
upper substantially vertical portion of the main knlfe shall
run.
To improve or on the whole make Possible the function
of the knife unit 13 it has proved that in addition to the
actual forward movement through the soil the knife unit has
to effect rapid reciprocatory movements. It has proved most
suitable for the leading knife 29 to move in such a way that
its edge effects rapid reci~rocatory movements in its longi-
tudinal direction. On the other hand, the main knife 30, to
ensure the best possible function, must effect rapid movements
transversely of the direction of the edge, that is, back and
forth in the direction of travel of the machine. These rapid
reciprocatory movements are generated by the drive mechanism
26 and are transferred via the substantially horizontal connect-
ing arm 27 to the upper end of the knife support 28. Baing
mounted for pivotment about a pivot axis 31 in relation to the
vertically adjustable arm 20, the knife sup~ort 28 will effect
a rapid pendulating movement about the pivot axis 31. As a
result, the main ]cnife which is arranged as an extension of
the knife support 28, will efect a reciproCatQry movement in
the direction of travel of the machine, said movement thus
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taking place substaintially a-t right angles to the edge of the
main knife. In order khat the leading knife 29 shall be given
a reciprocatory movement along its edge, said leading kni~e
is, as mentioned in the foregoing, arranged so as to make an
acute angle with the soil surface, but in addition it is placed -
in such a way in relation to the pivot axis 31 of the knife
support that the normal of the edge passes through the pivot
axis 31 or at least in its immediate vicinity. To permit
adjustment of the edge angle of the leading knife 29 relative
to the ground and at the same time adjustment of the clearance
angle ~ of the main knife, the connection arm 27 is of vari-
ble length.
As already mentioned, the drive mechanism 26 sets
the knife support 28 in a rapid penulating movement via the
connecting arm 27. The drive mechanism 26 (Fig. 3) is here
1 formed as an eccentric mechanism, the connecting arm 27
j functioning as a connecting rod. The eccentric mechanism 26
; is located within the upper end of the vertical frame portion
14 and is driven by and movable along a drive shaft 32 which
is mounted by sultable bearings in the vertical frame members.
The drive shaft 32 has a sprocket 33 and a chain 34 (Fig. 1)
running over said sprocket and connecting the drive shaft to
'l a corresponding sprocket of a miter wheel gearing 35. The
miter wheel gearing 35 is connected via the power take-o~f 4
to the tractor power take-off. In normal operation, tha power
take-off rotates at a speed of the order 400 rpm, while the
l drive shaft 32 rotates at a speed of the order 750 rpm. As
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1 ~ a result, the knife unit 13 will effect reciprocatory movements
at a frequency of approximately 750 strokes per minute. To
~ 30 permlt adjustment of the stroke length of the reciprocatoFy
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movements of the knife unlt the eccen-tric mechanism is
provided with an inner eccentric 38 which can be fastened
with the aid of a clamping sleeve to the drive shaft 32 and
which is accommodated in an eccentric hole in an outer
eccen-tric ring 37, the inner eccentric 38 and the outer
eccentric ring 37 being rigidly interconnectible so that
they will together form an eccen~ric of adjustable eccentricity.
A suitable bearing 40 is provided between the outer eccentric
ring and the crank end 36 of the connecting arm 27. By turn-
` lO ing the outer eccentric ring 37 relative to the inner eccen-
tric 38 and locking it in the set position the eccentric
mechanism can be so adjusted that the stroke of the knife
unit varies between lO (as represented by the shaft 32 in
its solid line position), and 30 mm as represented by the
shaft 32 in its dashed position, a stroke of about 2Q mm
being normally used.
The machine described in the foregoing is only an
embodiment of the invention and can therefore be modified by
one of ordinary skill in the art in several ways without
20 going outside the boundaries of the invention. Thus, it may
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be suitable in some cases that the person who in the described
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i embodiment of the machine walks after it and supervises its
function~and steers it laterally instead rides in a seat
arranged on the machine. In this case, the steering rod ll
is of another appearance and is suitably provided within ~asy
reach of the operator in his seat. Moreover, the adjustment
devlce 21 may also suitably be designed in such a way as to
be conveniently operable from the seat. ;
Even thou~h the knife unit 13 described in the fore-
30 going and shown in the drawings has proved to function in a
very advantageous manner, the leading knife 29 may be replaced -
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by a rotary circular knife which may either be suspended
in a knife support 2S or in the vertically adjustable arm 20.
The machine described above can also to great advan-
tage simply be used for weeding between the growing plant rows.
For this purpose, the knife units only are removed and replaced
by downwardly directed ~rmswhich are late~ally bent such that
the lower ends thereof run midway between the nlant rows. At
the lower ends of the arms are secured weeding knives which
as viewed from above may suitably be V-shaped and directed
with their apices forwardly and placed straight below the
pivot axis 31. To prevent weed collecting so far downwards
on the downwardly directed arms that the weeding knives or
the ground is influenced, the arms are arcuately curved rear-
wards so that their lowermost portions heavily slope rear-
wardly-upwardly in a known manner, whereby the weeds will be
lifted. It may also be suitable to secure,in the ~runing
assemblies,indicating antennae which show the lateral exten-
sion of the weeding knives, thereby to facilitate lateral
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steering. To prevent the wheels 23 sinking into the soil
loosened by the weeding knifes, the wheels should have as
large ground-engaging surfaces as ~ossible, that is, be
as wide as possible~
Although the machine is shown in a six-row embodiment
with six pruning assemblies, the machine may of course~have
another number of such assemblies, both a Iesser and a greater~
number.
Finally, lt may also in certain circumstances be
s~itable to use instead of the mechanical power transmission
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to the drlve shaft 32, for example a hydraulic ~ower trans-
mission. In this case a hydraulic motor drivin~ the shaft 32
could cause the knife support to pendulate at a frequency
continuously varying within a wide range. With a multi-row
embodiment of the machine it is also suitable to shift the :
phaces of the movements of the various knife su~ports in rela-
tion to each other, which may simply be done in such a manner
that the eccen~rics are angularly turned about the drive
shaft 32 relative to each other so that the largest radii of
the eccentrics will be substantially uniformly distributed
over the circumference of the drive shaft. By this arrangement,
the moment necessary for driving the knife su~ports 28 will be
more uniormly distributed around the drive shaft 32.
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