Note: Descriptions are shown in the official language in which they were submitted.
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DEVICE AND PROCESS FOR CUTTING GRASS WITH A
CONTROLLED THICKNESS FROM GRASS LAND
FIELD OF THE INVENTION
[0001] The present invention relates to cutting grass sods from grass land.
BACKGROUND OF THE INVENTION
[0002] Grass sod is utilized to quickly form large grass surfaces such as
sports
fields, golf courses and lawns. The grass sod is cut from a grass land and
typically
has a breadth of between 24 and 48 inches (60 - 120cm). The cut grass sod is
collected as a roll or a slab. An exemplary device and method for cutting out
large
grass sods are described in WO 95/02317 (PCT/NL94/00159).
[0003] It is desirable that the cut grass sods have a constant or uniform
thickness over its length and breadth. A problem with the conventional
techniques
for cutting broad grass sods is that, when the terrain is sloped over the
breadth of
the grass sod, such as having a slightly hollow or rounded surface profile,
the
thickness of the cut grass sods over the whole breadth is not constant or
uniform.
This varying thickness yields problems during laying of sports fields and the
like
which must be as flat as possible. Moreover, the thickness of the cut grass
sod is
dependent on the application. For example, a golfing green or a high quality
sports
field would utilize a grass sod that is preferably cut as thinly as possible.
Conversely, for gardens or planting grass fields, the grass sods can be cut
thicker.
If the grass sod is cut from a sloping terrain, a temporary "dead" spot can be
produced. This is a particular problem when the grass sod is cut as thinly as
possible, such as for golfing greens or high quality sports fields. In
applications
where thicker grass sods can be utilized, it may be important to cut the grass
sod at
a substantially constant thickness over its length or breadth, or both, in
order to
reduce transportation costs. Moreover, it is desirable to cut the grass sods
at a
substantially uniform thickness over its breadth in order to avoid a stack or
roll of
grass sods from sagging to one side or, in the case of narrow rolls or stacks
of
grass sods, from falling over.
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[0004] It is thus desirable to provide a method and apparatus for cutting a
grass
sod of a substantially uniform thickness over its length and breadth.
SUMMARY OF THE INVENTION
[0005] In an aspect of the present invention, there is provided an apparatus
for
cutting grass sods from a grass land. The apparatus includes a chassis; a
flexible
cutting blade having a cutting edge, adjustably mounted on the chassis for
cutting a
grass sod from the grass land when the chassis is moved relative to the grass
land,
the cutting edge defining a lateral direction; and adjusting means mounted on
the
chassis for flexing the cutting blade so as to adjust a lateral profile of the
cutting
edge. The apparatus may include a frame attached to the chassis. The cutting
blade may have two end portions and a middle portion between the end portions.
The cutting edge may extend from the middle portion towards the end portions.
The
middle portion may be secured to the frame. The end portions may be adjustably
supported by the adjusting means such that each one of the end portions is
moveable with respect to the frame for adjusting the lateral profile of the
cutting
edge. The adjusting means may include two adjustable cylinders mounted on the
frame, each one of the cylinders coupled to one of the end portions of the
cutting
blade for adjusting a position of the end portion relative to the middle
portion. The
apparatus may include measuring means for measuring changes in a lateral
surface profile of the grass land, the measuring means being coupled to the
adjusting means such that the adjusting means adjusts the cutting blade in
response to a detected change in the lateral surface profile of the grass
land. The
measuring means may include at least three running wheels mounted adjacent a
front end of the chassis, the running wheels distributed substantially
parallel to the
lateral direction for measuring the changes in the lateral surface profile of
the grass
land. The adjusting means may automatically adjust the cutting blade in
response
to the detected change. The apparatus may include sensing means for sensing a
thickness of a cut grass sod, the sensing means being coupled to the adjusting
means such that the adjusting means adjusts the cutting blade in response to a
detected variation in the thickness of the cut grass sod. The sensing means
may
include a plurality of sensors distributed substantially parallel to the
lateral direction
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for sensing a lateral variation of the thickness of the cut grass sod. At
least one of
the sensors may detect an electrical signal that is indicative of the
thickness of the
cut grass sod. The adjusting means may automatically adjust the cutting blade
in
response to the detected variation. The adjusting means may adjust the cutting
blade as the chassis moves relative to the grass land such that a grass sod
cut
from the grass land by the cutting blade has a substantially uniform lateral
thickness.
[0006] In another aspect of the present invention, there is provided another
apparatus for cutting grass sods from a grass land. The apparatus includes a
chassis; a cutting blade having a cutting edge, moveably mounted on the
chassis
for cutting a grass sod from the grass land when the chassis is moved relative
to
the grass land; adjusting means mounted on the chassis for adjusting a
position of
the cutting blade relative to the chassis; and sensing means mounted on the
chassis for sensing a thickness of a cut grass sod, wherein the sensing means
is
coupled to the adjusting means such that the adjusting means adjusts a
position of
the cutting blade in response to a detected variation in the thickness of the
cut
grass sod. The adjusting means may automatically adjust the position of the
cutting blade in response to the detected variation. The sensing means may
include a sensor capable of detecting an electrical signal that is indicative
of the
thickness of the cut grass sod. The sensing means may include a plurality of
sensors. The apparatus may include measuring means for measuring changes in a
surface profile of the grass land, the measuring means being coupled to the
adjusting means such that the adjusting means adjusts the position of the
cutting
blade in response to a detected change in the surface profile of the grass
land. The
measuring means may include a running wheel mounted adjacent a front end of
the
chassis for measuring the changes in the surface profile of the grass land.
The
measuring means may include a plurality of running wheels mounted adjacent the
front end of the chassis. The adjusting means may automatically adjust the
position
of the cutting blade in response to the detected change in the surface profile
of the
grass land. The adjusting means may adjust the cutting blade as the chassis
moves
relative to the grass land such that a grass sod cut from the grass land by
the
cutting blade has a substantially uniform thickness. The cutting blade may be
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flexible. The adjusting means may include an adjustable cylinder, the cutting
blade
at least partially supported by the adjustable cylinder. The adjusting means
may
include a plurality of adjustable cylinders each coupled to a portion of the
cutting
blade for adjusting a position of the portion of the cutting blade. The
sensing means
may be disposed between the cutting blade and a back end of the chassis.
[0007] According to a further aspect of the present invention, there is
provided
an apparatus for cutting grass sods from a grass land. The apparatus includes
a
chassis having a front end and a back end; a cutting blade having a cutting
edge,
moveably mounted on the chassis for cutting a grass sod from the grass land
when
the chassis is moved relative to the grass land, the cutting edge defining a
lateral
direction; adjusting means mounted on the chassis for adjusting a position of
the
cutting blade relative to the chassis; and at least three measuring means
disposed
in front of the cutting blade, the at least three measuring means laterally
distributed
for measuring a lateral surface profile of the grass land, wherein the at
least three
measuring means are coupled to the adjusting means such that the adjusting
means adjusts a position of the cutting blade in response to a detected change
in
the lateral surface profile of the grass land. Each one of the at least three
measuring means may include a running wheel. The adjusting means may
automatically adjust the position of the cutting blade in response to the
detected
change in the lateral surface profile of the grass land. The adjusting means
adjusts
the cutting blade as the chassis moves relative to the grass land such that a
grass
sod cut from the grass land by the cutting blade has a substantially uniform
lateral
thickness. The cutting blade may be flexible. The adjusting means may include
an
adjustable cylinder coupled to the cutting blade for adjusting the cutting
blade. The
adjusting means may include a plurality of adjustable cylinders each coupled
to a
portion of the cutting blade for adjusting a position of the portion of the
cutting
blade.
[0008] In another aspect of the present invention, there is provided a method
of
cutting from a grass land a grass sod having a predetermined thickness. The
method includes the steps of setting a cutting blade to cut from the grass
land the
grass sod having the predetermined thickness; positioning sensing means to
detect
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during cutting of the grass sod from the grass land a thickness of a cut grass
sod,
by detecting an electrical signal indicative of the thickness of the cut grass
sod;
detecting a variation in the thickness of the cut grass sod; and in response
to
detecting the variation, adjusting the cutting blade to maintain the cut grass
sod at
the predetermined thickness. The method may also include positioning measuring
means to detect during the cutting of the grass sod from the grass land a
surface
profile of a grass sod to be cut; detecting a change in the surface profile;
and in
response to detecting the change in the surface profile, adjusting the cutting
blade
to maintain the cut grass sod at the predetermined thickness.
[0009] According to a further aspect of the present invention, there is
provided a
method of cutting from a grass land a grass sod having a predetermined
thickness.
The method includes setting a flexible cutting blade to cut from the grass
land the
grass sod having the predetermined thickness; detecting during cutting of the
grass
sod from the grass land changes in at least one of a thickness of a cut grass
sod
and a surface profile of the grass land; and in response to detecting a change
in the
at least one of a thickness of the cut grass sod and the surface profile of
the grass
land, flexing the cutting blade to maintain the cut grass sod at the
predetermined
thickness.
[0010] According to yet another aspect of the present invention, there is
provided an apparatus for cutting grass sods from a grass land, comprising a
chassis having a front end and a back end; a roller mounted on the chassis
such
that the roller contacts a surface of the grass land when the chassis is moved
relative to the grass land; a cutting blade having a cutting edge, moveably
mounted
on the chassis adjacent the roller for cutting a grass sod between the roller
and the
cutting blade from the grass land when the chassis is moved relative to the
grass
land; adjusting means mounted on the chassis for adjusting a position of the
cutting
blade relative to the roller; and detection means for detecting at least one
of a
thickness of a cut grass sod and a surface profile of the grass land, wherein
the
detection means are coupled to the adjusting means such that the adjusting
means
adjusts a position of the cutting blade relative to the roller in response to
a detected
change in the at least one of the thickness of the cut grass sod and the
surface
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profile of the grass land.
[0011] According to yet another aspect of the present invention, there is
provided a method of cutting grass sods from a grass land, comprising: setting
a
cutting blade relative to a roller to cut from the grass land a grass sod
having a
predetermined thickness between the cutting blade and the roller; positioning
detecting means to detect during cutting of the grass sod from the grass land
at
least one of a thickness of a cut grass sod and a surface profile of the grass
land;
detecting, with the detecting means, changes in the at least one of the
thickness of
the cut grass sod and the surface profile of the grass land; in response to
detecting
a change in the at least one of the thickness of the cut grass sod and the
surface
profile of the grass land, automatically adjusting, with adjusting means
coupled to
the detecting means, a position of the cutting blade relative to the roller to
maintain
the cut grass sod at the predetermined thickness.
[0012] In an exemplary embodiment of the present invention, an exemplary
device for cutting one or more grass sods from grass land may include a
chassis,
cutting means for cutting the sods, which cutting means are mounted on the
chassis; and setting means for setting the cutting means. The exemplary device
may include measuring means for measuring the sod thickness, which measuring
means are workably coupled with the setting means. The measuring means may
include rolling and/or dragging means for feeling thickness variations in the
sods to
be cut. The rolling means may include two or more running wheels mounted in
front
of the cutting means, as seen from a side elevation of the device. Sensing
means
may be mounted behind the cutting means as seen in the driving direction of
the
device. The cutting means may include a flexible blade wherein the extent of
flexibility thereof is set up by the setting means.
[0013] Although an experienced driver of the exemplary device may be able to
adjust the cutting means during driving, it is preferable, when the device is
also
provided with measuring means, that setting of the cutting means occurs for as
much as is possible automatically, whereby the thickness of the grass sods can
be
kept constant or varied to a greater extent.
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[0014] The measuring means, rolling and/or dragging means are preferably
mounted on the cutting means so that the slopes in the terrain, from where the
grass sods are to be cut, are constantly felt whereafter immediate adjustment
of the
depth setting of the cutting means can occur.
[0015] In another embodiment, which can also make use of the mentioned
rolling and/or dragging means, sensing means are arranged behind the cutting
means wherein the setting means are adjusted as quickly as possible when an
undesirable depth is measured.
[0016] The cutting means preferably comprise a flexible blade since apart from
the depth setting of the cutting means with respect to the underground, a
partially
hollow or rounded cutting blade can also be set up in order to follow the
sloping
terrain.
[0017] There is also provided an exemplary process for cutting one or more
grass sods from grass land, wherein the thickness of the grass sods which have
been cut out or which are to be cut out, is determined and wherein the cutting
means are set up to depend on the measured thickness.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Further advantages, characteristics and details of the present
invention
will be clarified with respect to the following description of a preferred
embodiment
thereof, which refers to the appended drawings which show:
[0019] Fig. 1 is a perspective view of a preferred embodiment of the present
invention, with which a process according to an exemplary embodiment of the
present invention can also be carried out;
[0020] Fig. 2 is a more detailed perspective view of the portion II from Fig.
1 in a
first working condition; and
[0021] Fig. 3 is a more detailed perspective view of portion I I I from Fig. 2
in a
second working position.
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DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0022] A device 1 according to an exemplary embodiment of the present
invention comprises a chassis 2 whereon wheels 23, 24 are mounted and which is
connected with a tractor (not shown) via a coupling 3 and a rod 4. The device
1 can
also make use of a driven axle 5 of the tractor, in the schematically shown
manner,
and also of other provisions thereof.
[0023] A cutting unit 6 is disposed adjacent the front end of the chassis 2
for
cutting a grass sod S from a grass land. A carrying up transporter 7 and
transport
units 8, 9 and 10 are mounted on the chassis 2 for stacking up the grass sods,
for
example with large breadth, in large rolls or in a zig-zag manner on the
holder P.
Further details of the device illustrated in Fig. 1 are described in the above
mentioned international patent application W095/02317.
[0024] With reference to Fig. 2, and ongoing reference to Fig. 1, the cutting
unit
6 may include a somewhat flexible roller 11 and a cutting blade 12. As is
shown,
and typical in conventional grass sod cutting machines, roller 11 is mounted
on
chassis 2 in such a manner that roller 11 can contact the surface of the grass
land
during operation, when chassis is moved relative to the grass land. Also as
shown,
the cutting blade 12 has a cutting edge, which defines a lateral direction.
The
cutting blade 12 extends laterally between the sides of chassis 2, and is
positioned
behind the roller 11. The cutting blade 12 can be positioned to cut the sod
under
the surface of the grass land. The cutting blade 12 is mounted to a frame part
14
which is movably connected to chassis 2. Frame part 14 is connected to a
rotatable
axle 13. As the axle 13 is driven to rotate, the frame part 14, and hence the
cutting
blade 12, will move back and forth with respect to the chassis 2 and the
roller 11,
as indicated by the double arrow A. The cutting blade 12 is adjustable with
respect
to the roller 11 by the adjustment of the frame part 14, or the suspending of
the
roller 11.
[0025] The cutting blade 12 may be at least somewhat flexible. As shown, the
cutting blade 12 has two end portions and a middle portion between the end
portions. The cutting edge of cutting blade 12 extends from the middle portion
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towards the end portions. The middle portion may be secured in position
relative to
the frame part 14. Each of the end portions may be coupled to, such as
supported
by, an adjustable cylinder 16 or 17, which may in turn be mounted on opposite
sides of the frame part 14. The adjustable cylinders 16 and 17 may be
adjustable,
and may move up and down, as schematically illustrated in FIG. 2 and indicated
by
the double arrows C and D.
[0026] As shown in FIG. 3, the end portions of the cutting blade 12 may be
flexible with respect to the frame part 14. The position of each end portion
relative
to the frame part 14, and the middle portion of the cutting blade 12, may be
adjusted by moving adjustable cylinder 16 or 17, such as upwardly, to flex the
cutting blade 12, as illustrated. As can be understood, the cutting edge of
the flexed
cutting blade 12 has a curved lateral profile, which may make it possible to
cut out a
grass sod from a somewhat hollow sloping terrain, where the grass sod has a
substantially uniform lateral thickness over its whole breadth.
[0027] The hollows and bumps of the terrain may be measured, for example,
with the aid of running wheels 30, 31 and 32 which are secured to the frame
part
33, adjacent the front end of the chassis 2. As illustrated, the running
wheels may
be distributed substantially parallel to the cutting edge for detecting
changes in the
lateral surface profile of the grass land. As such, the running wheels 30, 31
and 32
form parts of the measuring means for measuring the surface profile of the
grass
land, which may be operatively coupled with the adjustable cylinders 16 and
17. No
particular embodiment of coupling is shown in the figures as suitable coupling
techniques for coupling the measuring means to the adjustable cylinders can be
readily provided by persons skilled in the art. Such a coupling may utilize
any
suitable conventional coupling techniques. As can be appreciated, the coupling
between the measuring means and the adjustable cylinders 16 and 17 makes it
possible to adjust the cutting blade 12 in response to a measured change in
the
lateral surface profile of the grass land, in order to keep the thickness of
the cut
grass sod substantially constant or uniform. The adjustments may be made
automatically, to adjust a position of the cuffing blade 12 relative to the
roller 11.
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[0028] As shown in Fig. 2, another preferred embodiment for keeping the
thickness of the sods over the complete breadth constant, utilizes sensors 40,
41,
42, 43, 44, 45 and 46 mounted on the frame (or the carrying-up transporter 7).
The
sensors 40 to 46 may detect the thickness of the cut sods, or changes or
variations
thereof, for example, with the aid of capacitive signals that are indicative
of the
thickness of the cut sods. As can be appreciated, a capacitive signal is a
kind of
electrical signal. As shown, the sensors 40 to 46 may be disposed between the
cutting blade 12 and the back end of the chassis 2, and may be distributed
substantially parallel to the lateral direction, such that they can sense
lateral
variations in the thickness of the cut sods. The sensors 40 to 46 may be
coupled to
the adjustable cylinders 16 and 17, to provide immediate back coupling to the
adjusting cylinders 16 and 17 for immediate adjustment of the positioning of
the
cutting blade 12 relative to the roller 11, in response to sensed
irregularities in the
sod thicknesses. Such adjustments may be made automatically. Thus, the
resulting cut grass sods may have substantially uniform thickness, either
laterally or
longitudinally, or both.
[0029] As illustrated in the exemplary embodiment shown in Fig.2, the sensors
40 to 46 and the running wheels 30 to 32 may be both provided in the same
apparatus for detecting changes in cut sod thickness and grass land surface
profile.
It can be appreciated that, regardless of where or when the changes or
variations
are detected during the cutting of the sods, either before the cutting out of
the sods,
or after the cutting out thereof, the detected changes or variations may be
used to
make a sufficiently accurate adjustment of the cutting blade 12 in order to
keep as
constant as possible the thickness of the sods, or indeed to vary the
thickness
thereof. Such a measurement or detection can of course take place elsewhere in
the device, for example, at the holder P where the cut sods are stacked. An
experienced driver can also visually determine the thicknesses of the sods
stacked
on holder P and adjust manually the cutting blade 12 accordingly.
[0030] As can be appreciated, a grass sod cut according to an embodiment of
the present invention may have a substantially uniform thickness, either
laterally (or
breadth-wise) or longitudinally (or length-wise), or both laterally and
longitudinally.
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[0031] The invention has been described with reference to exemplary
embodiments. Obvious modifications and alterations will occur to others upon
reading and understanding the preceding detailed description. It is intended
that the
invention be construed as inciuding all such modifications and alterations
insofar as
they come within the scope of the appended claims or the equivalents thereof.
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