Note: Descriptions are shown in the official language in which they were submitted.
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HAND-HELD FOOT ACTIVATED EXTRACTOR
FIELD OF THE INVENTION
The present invention relates to hand tools dedicated to weed removal and turf
aeration. More specifically, the present invention is directed to a hand-held
and
foot activated extractor providing automatic side ejection of turf or weed
root plug.
BACKGROUND OF THE INVENTION
Besides powered lawn aerators, some types manually operated turf aerators and
weed extractors already known in the prior art and available on the market.
Most
types either perform lawn aeration or weed extraction and require manual
actuation of a lever or piston to eject the plug of weed roots or soil at the
end of
each extraction cycle. Such manual tools for the removal of plugs from the
ground
are disclosed in US patents such as No. 4,819,735 (Puckett), 5,338,078 (Basek)
and 5,469,923 (Visser). Of course, manually operating a piston or like device
for
ejecting the plug after every cycle is tedious, requiring more time and energy
to
complete a weed extraction or an aeration job.
Some manual lawn aeration tools do not require plug removal since holes are
created by forcing solid prongs into the ground as taught in US patent No.
5 813,471 (Ramsey). However, it is well known that such a process creates
holes
by compacting the soil around it since no material is actually removed from
the
ground. Therefore, overall lawn compaction and soil hardness are not
efficiently
treated through such a technique, and holes tend to return to a closed status
more
rapidly. Also, such tools can obviously not be used for weed removal.
The prior art teaches a few examples of hand-held and foot activated weed
removal tools that can be used as well for aerating small lawn areas, and that
are
claimed to provide easy expulsion of the plug. US patent No. 6,330,921
(Barber)
and US patent application No. 2003/0037715 (Santa Cruz et al.) discloses such
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tools. Barber teaches a tool wherein a short annular cutting blade is
connected to
a retainer at a distal end of an elongate handle-attachment assembly. The
connection provides an axial gap between the annular blade and the retainer,
the
gap being open towards opposite sides of the attachment to facilitate removal
of
earth plugs cut by the annular blade. In the Santa Cruz application, the
efficient
end of the elongated tool in made from typical tubular metal stock provided
with an
elongate side opening for weed expulsion. From experience, it can be stated
that
such concepts do not provide efficient expulsion of the plug, which tends to
remain
jammed in the cutting means or be pushed and compressed against the portion of
the tube or retainer above the ejection opening when introducing a next plug
into
the tool, without first removing the previous one. Both situations necessitate
some
manual intervention from the user to clear the tool.
It would therefore be a significant advance in the art of plug extracting
tool, for
weed removal or lawn aeration, to provide a hand-held foot powered extractor
featuring self-clearing by auto-ejection of the previously cut plug every time
a new
plug is pushed in at the cutting end.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a hand-held foot activated
extractor for weed removal or lawn aeration which obviates the limitations and
drawbacks of the prior art tools, namely by featuring optimal cutter
configuration
and plug auto-ejection.
More specifically, in accordance with the present invention, there is provided
a
hand-held foot activated extractor comprising a stick having a first end with
a
handle and a second end with an extractor assembly. The extractor assembly
comprises a hollow tine defining i) a distal hollow frustoconical cutter
portion
defining a circular inlet provided with a cutting edge and a larger diameter
outlet, ii)
a hollow intermediate portion defining an arcuate wall extending
longitudinally from
the outlet of the distal hollow frustoconical cutter portion, an elongated
opening
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facing the arcuate wall and an elongated deflector sloping between the arcuate
wall and the elongated opening, and iii) a proximal stick connecting portion.
The
extractor assembly is also provided with a step projecting perpendicularly
from the
proximal stick connecting portion. In use, a material forced at the inlet of
the
frustoconical cutter portion loses frictional contact therein as it reaches
the outlet
thereof, and is directed by the deflector from the outlet toward the opening
for
ejection of the material from the extractor assembly.
The present invention also relates to the use of a hand-held foot activated
extractor according to the invention for removing weed roots or turf.
The present invention further provides a method of use of a hand-held foot
activated extractor according to invention. The method comprises the following
steps:
a) gripping the extractor handle with one hand and the extractor stick with
another hand to position the cutter edge on a turf area to be punched for
extraction of a plug containing a weed with roots or a healthy turf for
aeration,
b) placing a foot on the step of the extractor assembly,
c) applying a substantially vertical force therewith to insert the cutter into
the ground,
d) lifting the foot and pulling back with the hands the extractor containing
the extracted plug into the cutter, thereby leaving a neat hole into the
ground, and
e) repeating steps a) to d) so as the plug extracted into step d) is pushed
further downstream into the hollow tine by a next plug being forced into
the inlet during step d).
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Other features and advantages of the present invention will be better
understood
upon reading the following non restrictive description made with reference to
the
appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1a is a perspective view of a hand-held foot activated extractor
according to
a preferred embodiment of the present invention;
Figure 1 b is a front elevational view of the extractor of Figure 1 a;
Figure 1c is a side elevational view of the extractor of Figure 1a;
Figure 1d is an exploded view of the extractor of Figure 1a;
Figure 2a is as perspective view of an extractor assembly of the extractor of
Figure
1;
Figure 2b is a front elevational view extractor assembly of Figure 2a;
Figure 2c is a side elevational view of extractor assembly of Figure 2a;
Figure 2d is a top plan view of the extractor assembly of Figure 2a;
Figure 3a is a perspective view of a hollow tine of the extractor assembly of
Figure
2;
Figure 3b is a front elevational view of the hollow tine of Figure 3a;
Figure 3c is a side elevational view of tan hollow tine of Figure 3a;
Figure 3d is a plan view of the hollow tine of Figure 3a;
Figure 3e is cross sectional view of the hollow tine of Figure 3a, taken along
line
E-E of Figure 3d;
Figure 4a is a perspective view of a step of the extractor assembly of Figure
2;
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Figure 4b is a top plan view the step of Figure 4a;
Figure 4c is a side elevational view of the step of Figure 4a;
Figure 4d is front elevational view of the step of Figure 4a;
Figure 5 shows a side cross sectional elevation of a hollow tine according to
an
5 alternate embodiment of the extractor of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Figures la to 1d show different views of a hand-held foot activated extractor
1
according to the present invention. Extractor I mainly comprises a stick 2 to
which
a handle 3 is mounted at a proximal end thereof and an extractor assembly 20
assembled at a distal end thereof using a pair of rivets 4. Stick 2 is
preferably
made from wood, a rigid, light and cheap material often used in outdoor tools,
while handle 3 can be injection molded from an elastomer material to provide
an
efficient grip and enable easy press fit onto the wood stick 2. Thereby,
extractor 1
can be firmly held by a user, using both hands. The extractor assembly 20,
best
seen from Figures 2a to 2d, has a tapering receptacle 21 to receive the
frustum
portion 5 at the distal end of stick 2. Assembly 20 is assembled to stick 2 by
mounting rivets 4 through holes 22 registering with drilled holes (not shown)
in
frustum 5.
As shown in the different views of Figures 2a to 2d, assembly 20 comprises a
step
23 and a hollow tine 30. Hollow tine 30 is preferably formed from a single
piece of
sheet metal. Advantageously, step 23 and tine 30 (see Figures 3a to 3e for
details)
are both preferably made from strong wear and weather resistant material such
as
galvanized or stainless steel (or steel painted after forming), die cut and
folded
from sheet form. Step 23 (see Figures 4a to 4d) comprises a foot engaging
surface 24 provided with anti-slip ridges 25, and side panels 26 welded to the
outer surface of the receptacle end 31 of tine 30 at their straight edges 27
to
ensure a strong and stable assembly of step 23. The foot engaging surface 24
extends substantially orthogonal to the longitudinal axis of stick 2 and tine
30, so
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that a user can conveniently push the step with a foot to help driving the
tine into
the ground.
Tine 30, best viewed from Figures 3a to 3e, comprises three principal
portions.
The proximal stick mounting frustoconical receptacle portion 31 with holes 22
as
described above, a distal frustoconical cutter portion 32 and an intermediate
portion comprising an embossed arcuate wall 33 and an elongated opening 34.
The cutter portion 32 defines a circular cutting edge 35 bordering a circular
inlet
36. The frustoconical cutter 32 also defines an outlet 37 of larger inner
diameter
than inlet 36. The tapering angle defined by the inner frustoconical surface
of the
cutter portion tapering in the direction of the cutting edge should be from 1
to 10
degrees, with a preferred value of 5 degrees. This important feature is meant
to
ensure that the cut material, forming a plug having a diameter substantially
equal
to that of cutting edge 35, forced into inlet 36 gradually loses friction with
the inner
peripheral wall 38 as it moves toward cutter outlet 37. Thereby, the plug
becomes
substantially loose and easy to transport toward opening 34 for ejection. This
feature also ensures that minimal pressure is required to force a next plug
into
inlet 36 still containing the previous plug that must be pushed further
downstream
by said next plug being cut, but still enough pressure, which combined with
the
length of the cutter 32, provide sufficient friction to pull out the plug from
the
ground. In order to enable the extractor to be usable effectively for weed
removal
as well as for turf aeration, the inlet diameter is preferably selected to be
between
1.5 and 3 cm, with a preferred value of about 2 cm. Also, the length of the
elongated opening 34 is advantageously selected to be between 2 and 6 cm.
According to a preferred embodiment, the cutter portion 32 defines a
peripheral
wall 38 of generally uniform thickness extending between the cutting edge 35
and
the outlet 37.
Since the cutter is advantageously made from uniform thickness sheet material
for
ease of production and low cost, the outer shape of the cutter portion 32 is
generally identical to its inner shape, with slightly larger dimensions. The
conical
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shape added to the effect of thickness tends to create ground compression
around
the hole and increase the force required to drive the cutter into the ground.
To limit
these side effects to an acceptable extent, wall thickness is minimized to
about 1.6
mm to provide sufficient structural force, and a tapering angle below or equal
to 10
degrees also provides good results. In other words, this means that the cutter
portion defines an outer frustoconical surface tapering in the direction of
the
cutting edge with an angle of 0 to 10 degrees. However, an outer tapering
angle is
not necessary for adequate performance of the extractor 1; therefore an
alternate
embodiment with a straight cylindrical outer surface of the cutter portion 32
can be
contemplated, as long as the inner configuration still provides a tapering
angle to
promote easy plug ejection. The inventor although considers this embodiment as
generally less cost effective to produce.
The height of the cutter portion 32, from the cutting edge 35 to the outlet 37
is
another factor governing adequate performance of the extractor 1. It must be
long
enough to effectively retain the plug into the cutter by friction so to pull
it out from
the ground, leaving a clear hole, but not too long to produce excessive
friction with
the soil and peripheral ground material surrounding the hole so to prevent the
same from being pulled out, thus forming ribbed craters and damaging the
ground
surface. Therefore, the length of the cutter portion from the cutting edge to
the
outlet is preferably larger than the diameter of the cutting edge with a ratio
between 1.1 and 1.5. A ratio of the cutter height to inlet diameter of about
1.5 has
been found to allow optimal performance in the preferred embodiment featuring
a
thin wall frustoconical cutter portion as described heretofore.
It is also worth mentioning that while a circular geometry of the cutter
portion 32
has been described so far, equivalent functions and performance would be
obtainable from a cutter having a substantially different cross section. For
example, a pyramidal square or triangular cross section cutter can be
contemplated. Therefore, the scope of the present invention should be deemed
to
include all alternative shapes, although the round shape is adequate and more
practical for the applications contemplated herein.
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The intermediate third portion of the hollow tine 30, connecting the distal
cutter
portion 32 to the proximal stick mounting receptacle portion 31 will now be
described in detail referring to Figures 3a to 3e.
The intermediate portion comprises an arcuate U shaped wall 33 provided with a
deflector defined by a longitudinal wedge shaped embossment 39 tapering in the
direction of the cutter outlet 37. The wall 33 of this intermediate portion
comprises
an arcuate back portion and two longitudinal non-convergent wing portions 40
extending from each side of the arcuate portion and being tangent to this
arcuate
portion and forming longitudinal edges of the elongated opening 34.
The wall 33 covers about half of the periphery of the intermediate portion,
while
the opposite second half defines the elongated opening 34 having a length
substantially equal to that of the wall 33. The opening 34 serves as an exit
for
ejection of extracted plugs out of the extractor 1. Therefore, lateral sides
of wall 33
defining the pair of straight non-converging wings 40 extending slightly
beyond the
centre axis of tine 30 render the hollow intermediate portion stronger and
help to
properly guide extracted plugs toward the opening 34 without causing any
restriction. To ensure proper deviation of plugs toward opening 34, the higher
relief
portion near the downstream end of the longitudinal wedge shaped embossed
deflector 39 projects from the inner surface of wall 33 to a distance
approximately
equal to half the diameter of the cutting edge 35.
In operation, a user holds the extractor 1 by gripping handle 3 and stick 2
with two
hands to position the cutter edge on a turf area to be punched for extraction
of a
plug containing the roots of a weed or a healthy turf for aeration. The large
opening 34 may serve as a window to help the user to accurately position the
cutter in the case of weed removal. The user then places a foot on surface 24
of
step 23 and applies a substantially vertical force therewith to drive the
cutter into
the ground, preferably to a depth of about 5 to 8 cm, and then lifts the foot
and
pulls back the extractor with the hands. A plug is extracted and remains into
the
cutter leaving a neat hole into the ground. Repeating the process causes the
first
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plug to be pushed further upstream into the hollow tine by the next plug being
forced into inlet during the insertion phase. Depending on the depth of
insertion,
the first plug will typically be ejected through the opening 34 each time a
next plug
enters completely into the tine. Embossment 39 sloping in the direction of the
opening 34 ensures that a plug entering the intermediate portion of the hollow
tine
30 is deviated toward the opening and exits the extractor instead of naturally
hitting the bottom of the distal end of stick 2 causing rapid clogging of the
tine.
It should be noted that the deflector 39, formed by a longitudinal wedge
shaped
embossment in wall 33 according to the embodiment described heretofore, could
be implemented differently for substantially equivalent results. The basic
principle
must remain to provide a sloping member along a path originating from the
intersection of wall 33 and outlet 37 and crossing the center axis of the
tine. In
other words, the deflector 39 is preferably defined by a sloping member
extending
from a proximal end of the opening 34 and sloping inwardly into the hollow
tine
toward an intersection between the wall 33 and the outlet 37. For example, a
tab
50 (see Figure 5) extending from the base of the receptacle portion 31 above
opening 34 into the direction of the lower portion of wall 33 could be
provided.
Such a tab could be formed from material removed to create opening 34.
One can thus easily appreciate that the above described embodiments of the
hand-held foot activated extractor according to the present invention obviate
the
limitations and drawbacks of the prior art devices, namely by providing
reliable and
neat extraction as well as automatic ejection of the plugs. Therefore, it can
be
seen that the extractor can be advantageously used for removing weeds or
performing small elongated holes into a ground for aeration or any other
purpose.
Although the present invention has been described hereinabove by way of
preferred embodiments thereof, it can be modified, without departing from the
spirit and nature of the subject invention as defined in the appended claims.
