U.S. patent application number 10/411607 was filed with the patent office on 2004-10-14 for ground anchor for use with natural ground cover.
Invention is credited to Smith, Michael C..
Application Number | 20040202512 10/411607 |
Document ID | / |
Family ID | 33131026 |
Filed Date | 2004-10-14 |
United States Patent
Application |
20040202512 |
Kind Code |
A1 |
Smith, Michael C. |
October 14, 2004 |
Ground anchor for use with natural ground cover
Abstract
A biodegradable ground anchor for use in conjunction with a
ground cover. The anchor includes a head portion that has opposite
surfaces and a peripheral surface. A pair of integral legs depend
away from one of the opposite surfaces. The legs are generally
parallel with respect to each other. Each of the legs includes a
pair of fins. The distal end of each leg terminates in a point. The
ground anchor is made from a polylactide polymer that is
biodegradable.
Inventors: |
Smith, Michael C.;
(Fairview, TN) |
Correspondence
Address: |
BELSHEIM LAW OFFICE
STEPHEN T. BELSHEIM
179 BELLE FORREST CIRCLE
SUITE 102
NASHVILLE,
TN
37221
US
|
Family ID: |
33131026 |
Appl. No.: |
10/411607 |
Filed: |
April 10, 2003 |
Current U.S.
Class: |
405/259.1 ;
52/155 |
Current CPC
Class: |
E02D 5/80 20130101 |
Class at
Publication: |
405/259.1 ;
052/155 |
International
Class: |
E02D 005/74; E21D
020/00 |
Claims
1. A biodegradable ground anchor for use in conjunction with a
ground cover, the anchor comprising; a head portion having opposite
[surface] top and bottom surfaces and a peripheral surface; a pair
of integral legs depending away from one of the opposite surfaces,
the legs being generally parallel with respect to each other; each
of the legs including a pair of fins; the distal end of each leg
terminating in a point intended to assist in penetrating the
ground; and the ground anchor being made From a polyactide polymer
that[s] is biodegradable.
2. A ground cover blanket system comprising: a ground cover
blanket, the blanket having cross-hatched members; a biodegradable
ground anchor for penetrating the ground, the ground anchor
comprising a head portion having opposite [surface] top and bottom
surfaces and a peripheral surface; a pair of legs depending away
from one of the opposite surfaces, the legs being generally
parallel with respect to each other; each of the legs including a
pair of fins; the distal leg of each leg terminating in a point;
and the ground anchor being made from a polylactide polymer that is
biodegradable.
3. The ground cover blanker system of claim 2 wherein the
groundcover blanket is a soil erosion control blanket.
4. The ground anchor of claim 1 wherein the head portion being
generally rectangular in shape.
5. The ground anchor of claim 1 wherein the head portion being
generally square in shape.
6. The ground anchor of claim 1 wherein the head portion being
generally oval in shape.
7. The ground anchor of claim 1 wherein the head portion being
generally circular in shape.
8. The ground anchor of claim 1 wherein the legs depend away from
the bottom surface of the head portion.
9. A biodegradable ground anchor for use in conjunction with a
ground cover wherein the ground anchor is driven into the ground so
as to retain the ground cover to the ground, the ground anchor
comprising: a head portion having opposite top and bottom surfaces
and a peripheral surface, and the top surface of the head portion
being impacted upon the ground anchor being driven into the ground;
a pair of integral legs depending away from the bottom surface of
the head portion, the legs being generally parallel with respect to
each other, and the legs being sufficient rigid so as to maintain
their structural integrity upon being driven into the ground; each
of the legs including a pair of chevron-shaped fins; the distal end
of each leg terminating in a point that assists in the ground
anchor penetrating the ground; and the ground anchor being made
from a polylactide polymer that is biodegradable so that the
structural integrity of the ground anchor diminishes as the ground
anchor remains in the ground.
Description
BACKGROUND OF THE INVENTION
[0001] Soil erosion has been a concern for a number of years. In
many types of construction projects the movement or excavation of
soil has left soil bare and subject to erosion. One exemplary
excavation project is road construction. While grass seed or other
ground cover may be planted on the bare soil, the seed may be
washed away before it can grow so that erosion may still be a
problem.
[0002] In an effort to combat soil erosion, there has been
developed a soil erosion control blanket. One such blanket is the
Robexshield.TM. RS-1 straw erosion control blanket. U.S. Pat. No.
5,786,281 to Prunty et al. also shows an erosion control blanket.
Typically, erosion control blankets have been placed on the bare
soil and then attached to the ground via ground spike or spikes.
Ground spikes are positioned in a pattern so as to securely attach
the soil erosion control blanket to the ground. Over the course of
time it is not unusual for the ground spikes to work themselves in
a direction so that the upper end of the ground spike is exposed
above the surface of the ground.
[0003] As the grass or other ground cover grows it will become
necessary to mow the grass or the ground cover. When mowing in an
area in which ground spikes have a portion exposed above the
ground, there is a reasonable possibility that the mower blade may
impact the ground spike so as to pull it out of the ground and
project it away from the mower. In another type of occurrence, the
mower blade may impact a ground spike fully inserted into the
ground when the blade scraps or digs into the ground. Either one of
these occurrences can result in the ground spike being projected
towards a person such as occupants of a motor vehicle in the case
of road side mowing thereby exposing such persons to the dangers
connected with being struck with the flying ground spike. It this
becomes apparent that there would be a benefit if there would be a
ground anchor that did not have the tendency to work its way up out
of the ground. This could occur through the use of structure that
would help maintain the ground anchor in the ground.
[0004] Still referring to the potential harm associated with a
mower blade striking a ground spike, it would also be desirable if
there would be a ground anchor that had a structure so that it
would not be able to be effectively projected upon impact with a
mower blade. For example, that the ground anchor would have the
tendency to disintegrate upon impact with the mower blade.
[0005] In the case of steel ground spikes, and even ground spikes
made out of other material, the absence of a biodegradable property
or the presence of a slow biodegradable property can be
undesirable. It would thus be desirable to provide a ground anchor
that is biodegradable. It would also be desirable to provide a
ground anchor that remains biodegradable only for an amount of time
sufficient (or that can be designed to remain biodegradable only
for an amount of time sufficient) to secure the soil erosion
control blanket for an adequate period of time until there is no
longer a need for the erosion control blanket. For example it would
be desirable to provide a ground anchor that decomposed at a
predetermined rate so that at the time of the first mowing (or at
least during the earlier mowings) it would not have the structural
integrity to be projected (or projected any significant distance)
upon impingement with a mower blade.
[0006] Heretofore, ground spikes have been generally driven into
the ground by hand to secure the erosion control blanket. The
nature of this activity is inherently physically detrimental to the
worker. It would thus be desirable to provide a ground anchor that
could be driven by a gun or the like so as to decrease the physical
stress to the worker.
SUMMARY OF THE INVENTION
[0007] In one form thereof, the invention is a biodegradable ground
anchor for use in conjunction with a ground cover. The anchor
includes a head portion that has opposite surfaces and a peripheral
surface. A pair of integral legs depend away from one of the
opposite surfaces. The legs are generally parallel with respect to
each other. Each of the legs includes a pair of fins. The distal
end of each leg terminates in a point. The ground anchor is made
from a polylactide polymer that is biodegradable.
[0008] In another form thereof, the invention is a ground cover
blanket system that comprises a ground cover blanket that has
cross-hatched members and a biodegradable ground anchor. The ground
anchor has a head portion with opposite surface surfaces and a
peripheral surface. The anchor also has a pair of legs that depend
away from one of the opposite surfaces wherein the legs are
generally parallel with respect to each other. Each of the legs
includes a pair of fins. The distal leg of each leg terminates in a
point. The ground anchor being made from a polylactide polymer that
is biodegradable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Set forth below is a brief description of the drawing
figures that make up a part of this patent application:
[0010] FIG. 1 is an isometric view of an erosion control blanket
positioned on the ground (or earth strata) and earth strata
sectioned away so as to show a ground anchor (10) prior to entry
into the earth strata, a ground anchor (10A) partially into the
ground, and a ground anchor (10B) fully inserted into the
ground;
[0011] FIG. 2 is an isometric view of a first specific embodiment
of a ground anchor wherein a portion of the head section of the
ground anchor is broken away to show the joinder of the leg to the
head portion;
[0012] FIG. 3 is an isometric view of a second specific another
embodiment of a ground anchor wherein the ground anchor has a round
head;
[0013] FIG. 3A is an isometric view of a gun (along the line of a
double barreled shotgun) that installs (or drives) the ground
anchors shown in FIG. 3 into the ground;
[0014] FIG. 4 is an isometric view of a third specific embodiment
of a ground anchor wherein the ground anchor has a square head;
and
[0015] FIG. 5 is a side view of the ground anchor shown in FIG.
2.
DETAILED DESCRIPTION
[0016] Referring to the drawings, FIG. 1 illustrates a specific
embodiment of the ground anchor generally referred to as 10 in
conjunction with a soil erosion control blanket 12. Although other
blankets may be applicable to use, one preferred blanket is the
RS-1 Straw Erosion Control Blanket made by Robexshield, 5830
Highway 161, Springfield, Tenn. 37172. Applicants also contemplate
that the ground anchors of the present invention may be used in
conjunction with various types of ground cover (e.g., turf, seed
blankets, and the like) wherein the ground cover must be secured to
the ground.
[0017] Soil erosion control blanket 12 is shown rolled out on top
of the ground. The blanket 12 is essentially flat on the surface of
the ground 14. Referring to the position of the ground anchors,
ground anchor 10 is shown in a position above the ground prior to
being driven into the ground. The ground anchor designated as 10A
is a ground anchor that has been partially driven into the ground.
The ground anchor designated as 10B is a ground anchor that has
been completely driven into the ground so as to engage a part of
the blanket 12 and thereby attach the blanket 12 to the ground (or
earth strata) 14. As can be appreciated, a number of different
nailing or stapling arrangements of the ground anchors 10 may be
used to attach the blanket 12 to the ground 14.
[0018] Referring to FIG. 2, the ground anchor 10 includes an oval
head 16 at the upper end thereof. In the drawing a portion of the
head 16 is broken away. Head 16 has a top surface 18 and an oval
peripheral surface 20. Head 16 further includes a bottom surface
24.
[0019] A pair of generally parallel legs 26 depends from the head
16 of the ground anchor 10. Although it is not illustrated in the
drawings, for manufacturing purposes a small tab extends between
the legs to maintain the position of the legs while they are still
hot or warm from the injection molding operation. The legs 26 are
integral with the head 16.
[0020] Each one of the legs 26 has an upper (proximal) end 28 that
joins the bottom surface 24 of the head 16. Each leg 26 also has a
distal end 30 that comprises a sharp point. The distal end 30 (or
point) is the termination of the tapered (or conical) portion 32
adjacent the distal end 30. Each leg 26 has two pairs of fins 36
and 38 spaced between the proximal end 28 and the distal end 30.
These fins 36, 38 are positioned closer to the distal end 30 than
to the proximal end 28. Each fin 36, 38 has a chevron shape. Each
fin 36, 38 is swept back in the direction of the proximal end 28 so
that these fins 36, 38 resist the tendency of the ground anchor 10
to work its way out of the ground.
[0021] Referring to FIGS. 2 and 6, the overall length of the ground
anchor is dimension "A". The longitudinal dimension of the head 16
is dimension "B". The transverse dimension of head 16 is dimension
"C". The thickness of head 16 and legs 26 is dimension "D". The
spacing of the legs 26 is dimension "E". Exemplary dimensions and
ranges of dimensions are set forth in Table 1 below that presents
the above dimensions.
1TABLE 1 Dimensions Of Ground Anchor Dimension Magnitude (Inches) A
2.0-6.0 B 1.375 C 0.5 D .150-.190 E 1.0
[0022] It should be appreciated that there is no intention to
restrict the present invention to the above dimensions. These
dimensions may vary depending upon the specific application for the
ground anchor.
[0023] Referring to FIG. 3, the ground anchor as generally
designated 50 includes a round head 52 at the upper end thereof.
Head 52 has a top surface 54 and a round peripheral surface 56 Head
52 further includes a bottom surface (not shown). A pair of
generally parallel legs 58 depend from the head 52 of the ground
anchor 50. Legs 58 are integral with the head 52. As mentioned
earlier, there is a small tab 63 of material that extends between
the legs to maintain their position while still hot or warm after
the injection molding operation. Each one of the legs 58 has an
upper (proximal) end that joins the bottom surface of the head 52.
Each leg 58 also has a distal end 66 that comprises a sharp point.
The distal end 66 (or point) is the termination of a tapered (or
conical) portion 64. Each leg 58 has two pairs of fins 60 and 62
spaced between the proximal end and the distal end 66. These fins
60, 62 are positioned closer to the distal end 66. Each fin 60, 62
has a chevron shape so that each fin 60, 62 is swept back in the
direction of the proximal (or upper) end. These fins (60,62) resist
the tendency of the ground anchor 50 to work its way out of the
ground.
[0024] Referring to FIG. 3A, the ground anchor 50 is shown in
conjunction with a anchor gun 100. The purpose of the anchor gun
100 is to drive the ground anchors 50 into the ground without the
workers having to bend over each time as is required with manually
driving or nailing the anchors into the ground. It is physically
easier and leads to less of a chance for physical injury if the
worker does not have to bend over each time, but instead, can use a
anchor gun along the lines of anchor gun 100 which does not require
the worker to bend over for installation of each anchor.
[0025] Anchor gun 100 has a firing mechanism enclosed by a housing
102 and a handle 104 that extends from the housing 102. As one
option, the firing mechanism may be pneumatically driven. The
anchor gun 100 further has a trigger 106. The anchor gun 100 is
shown as having two barrels 108 wherein the anchors 50 feed into
the barrels 108 through openings 110. The length of each one of the
barrels 108 is such so that the worker does not have to bend over
to insert a anchor into the ground. By using the anchor gun 100,
the worker does not have to bend over and manually drive the ground
anchor into the ground. It should be appreciated that the anchor
gun may take on any one of a number of different configurations so
as to be useful for the insertion of ground anchors into the
ground.
[0026] Referring to FIG. 4, the ground anchor generally designated
as 70 includes a square head 72 at the upper end thereof. Head 72
has a top surface 74 and a square peripheral surface 76. Head 72
further includes a bottom surface. A pair of generally parallel
legs 78 depend from the head 72 of the ground anchor 70. Legs 78
are integral with the head 72. Like for the above embodiments, for
a manufacturing viewpoint it is preferred that a small tab of
material extends between the legs so as to maintain their position
after injection molding while the part is still hot or warm and
subject to deformation.
[0027] Each one of the legs 78 has an upper (proximal) end that
joins the bottom surface of the head 72. Each leg 78 also has a
distal end 86 that comprises a sharp point. The distal end 86 (or
point) is the termination of a tapered (or conical) portion 84.
Each leg 78 has two pairs of fins 80 and 82 spaced between the
proximal end and the distal end 86. Each fin 80, 82 has a chevron
shape so that each fin 80, 82 is swept back in the direction of the
proximal end. Like for the other fins, these fins (80, 82) resist
the tendency of the ground anchor 70 to work its way out of the
ground.
[0028] Ground anchors 10, 50 and 70 are made from an injection
moldable polymer that is biodegradable. One example of such a
material is PLA Polymer 3000D sold by Cargill Dow Natureworks.RTM.,
15305 Minnetonka Blvd., Minnetonka, Minn. 55345. According to
published literature, the PLA Polymer 3000D is a polyactide resin.
Based upon information from published literature, the Tables 2 and
3 below present the typical processing temperature profile of PLA
Polymer 3000D and the Typical Material Application Properties for
PLA Polymer 3000D.
2TABLE 2 Processing Temperature Profile Melt Temperature
390.degree. F. (200.degree. C.) Feed Throat 70.degree. F.
(20.degree. C.) Feed Temperature (crystalline pellets) 330.degree.
F. (165.degree. C.) Feed Temperature (amorphous pellets)
300.degree. F. (150.degree. C.) Compression Section 380.degree. F.
(195.degree. C.) Metering Section 400.degree. F. (205.degree. C.)
Nozzle 400.degree. F. (205.degree. C.) Mold 75.degree. F.
(25.degree. C.) Screw Speed 100-175 rpm Back Pressure 50-100 psi
Mold Shrinkage .004 in/in. +/- .001
[0029] In the processing of the material, applicant prefers that
the injection molding occur at a temperature that range between
about 380 degrees Fahrenheit and about 431 degrees Fahrenheit.
3TABLE 3 Typical Material Application Properties PLA Resin ASTM
(General Purpose Method Physical Properties Specific Gravity 1.21
D792 Melt Index, g/10 min (190 C/2.16 K.degree. 10-30 D1238 Clarity
Transparent Mechanical Properties Tensile Yield Strength, psi (MPa)
7,000 (48) D638 Tensile Elongation, % 2.5 D638 Notched Izod Impact,
ft-lb/in (j/m) 0.3 (0.16) D256 Flexural Strength (MPa) 12,000 (83)
D790 Flexural Modulus (MPa) 555,000 (3828) D790
[0030] According to literature, the PLA polymer 3000D has been
shown to biodegrade in a fashion similar to paper under simulated
composting conditions per ASTM D5338 at 50 degrees Centigrade.
Although the soil conditions may vary, it is applicant's intention
that the ground anchor will biodegrade at a rate such that as of
the time of the first mowing (or the second mowing) in the case of
ground cover that the ground anchor will not have the structural
integrity to be propelled upon impingement by a lower blade. It is
also applicant's intention that the ground anchor will have
sufficient structural integrity so as to maintain the soil erosion
control blanket in position for the extent necessary. Applicant
notes that the time it takes for the anchor to biodegrade can be
varied by varying the thickness of the anchor. For example, a
thinner anchor would be expected to degrade sooner than a thicker
anchor.
[0031] All patents, patent applications, articles and other
documents identified herein are hereby incorporated by reference
herein.
[0032] Other embodiments of the invention may be apparent to those
skilled in the art from the consideration of the specification or
the practice of the invention disclosed herein. It is intended that
the specification and any examples set forth herein be considered
as illustrative only, with the true spirit and scope of the
invention being indicated by the following claims.
* * * * *