Note: Descriptions are shown in the official language in which they were submitted.
CA 02520080 2005-09-16
Title of The Invention
HELICAL GROUND ANCHOR AND METHOD OF ITS USE
Technical Field of the Invention
The present invention relates generally to ground anchors. In particular, the
invention relates to
a ground anchor for securing and installing posts for use in fencing or other
construction.
Background of the Invention
Several problems arise when securing posts for construction, such as are used
for fences,
greenhouses, sheds, etc. in loose, wet, inaccessible or otherwise difficult
ground. Firstly, the
retention of a post in the ground is lessened by variable soil conditions such
as soil compactness,
water saturation, and variable water levels which may reduce the amount of
force required to
dislodge a post. Secondly, traditional wooden posts remaining in wet soils
have a limited life
span, usually no more than ten years, as they are susceptible to rot and decay
when immersed in
a moist soil environment. Thirdly, installed posts, whether pounded or
reinforced by a concrete
pour, are difficult to maintain, extract or adapt, and are generally non-
reusable.
These problems may be overcome through use of a tapered helical anchor of
durable material
such as plastic or corrosion resistant metal, and a serviceable platform for
the maintenance of the
above ground portion of the supporting post structure. Temporary and seasonal
fencing is
possible using this durable and reusable design.
There are a number of desirable objectives in relation to screw-type ground
anchors. Such
anchors should preferably be made of plastic or other corrosion resistant
material, and should be
easy to install, maintain, extract and reuse. For ease of manufacture, they
should be of an
integrated design, and preferably hollow to reduce material costs. For optimal
ground entry and
post support, they should ideally provide a notched boring tip, and a
continuous helix which
tapers inward toward the base of the anchor and provides a wide, pitched
thread. The anchor
should also provide a secure post mount which is adaptable to a variety of
posts. Existing
ground anchors achieve some of these objectives, but with varying degrees of
success.
srb'srb01968
i
CA 02520080 2005-09-16
-2-
It is known to provide a screw-type device for anchoring a post. Such a device
is described in
European Patent Patent No. 0542692 to Moore. Moore teaches a helical anchor
pile preferably
made of plastic and having a base plate for anchoring of a post to the top
surface of the anchor.
The anchor in Moore is directed to anchoring an otherwise free-standing
structure such as a
transmission tower.
It is also known to provide a screw-type ground anchor for low stress,
temporary installations
such as beach umbrellas. Such a device is described in U.S. Patent No.
5,046,699 to Perreault.
The anchor in Perreault provides a helix only at the lowermost end of the
anchor. Such a helix is
sufficient for temporary installations designed for easy removal, but would be
insufficient for
long term post installations.
Other helical ground anchors are known. In French Patent No. 2,571,771, Rovera
discloses a
screw-type ground anchor in which the anchoring helix does not taper until the
lowermost region
of the anchor, and the thread pitch is constant. Pylant, in U.S. Patent No.
6,412,235, teaches a
ground anchor with non-tapered screw threads only near the tip of the anchor.
Summary of the Invention
In one embodiment, the invention comprises a ground anchor system for
anchoring a post
comprising a base plate, a housing extending above the base plate, an anchor
extending below
the base plate, the anchor comprising a tapered helix having a thread
encircling a tube which
tapers inwardly towards the lower end of the anchor, and a boring tip at the
lower end of the
anchor.
The base plate, housing, anchor and boring tip may be structurally integrated,
and may be
manufactured by injection over-molding onto a metal tube, by extrusion, or by
casting.
The upper end of the helix may begin at the base plate or below the base plate
a distance of no
greater than 25% of the combined length of the anchor and boring tip. The
lower end of the
helix may end above the end of the boring tip a distance of no greater than
50% of the combined
length of the anchor and boring tip.
srb'sr60196R
CA 02520080 2005-09-16
-3-
The helix may taper inwardly towards the lower end of the anchor at a constant
angle of between
l and 30 degrees relative to the vertical plane, or at a continuously
increasing angle in the range
between 1 and 30 degrees relative to the vertical plane.
The angular pitch of the thread may be constant and may be between 3 and 30
degrees relative to
S the horizontal plane, or the thread mat taper from a first width proximal to
the tube to a second
narrower width distal to the tube.
The housing may comprise solid walls or non-solid walls. At least one interior
wall of the
housing may comprise friction enhancing means. The friction enhancing means
may be at least
one vertical ridge or a plurality of fins. The housing may further comprise
post attachment
means. The post attachment means may be one or more bolts, one or more screws,
or a threaded
adaptor lining the housing for receiving a threaded post. The housing further
may comprise one
or more insertable elements to reduce the horizontal cross-sectional area of
the housing.
The boring tip may be crimped, and there may be an opening between the housing
and the tube
of the anchor. The material used to manufacture the base plate, housing,
anchor and boring tip
may be a plastic. The plastic may be a recycled polyethylene terephthalate,
and it may be a dark
colour.
In another embodiment, the invention comprises a ground anchor system for
anchoring a post
comprising a base, plate, a housing extending above the base plate, an anchor
extending below
the base plate, the anchor comprising a tapered helix having a thread
encircling a tube which
tapers inwardly towards the lower end of the anchor, and a boring tip at the
lower end of the
anchor, wherein the helix begins at the base plate and ends above the end of
the boring tip a
distance of no more than 50% of the combined length of the anchor and boring
tip and tapers
inwardly towards the lower end of the anchor at an angle of between 1 and 30
degrees relative to
the vertical plane, the thread has a constant angular pitch of between 3 and
30 degrees relative to
the horizontal plane and tapers from a first width proximal to the tube to a
second narrower
width distal to the tube, and the base plate, housing, anchor and boring tip
are manufactured by
injection over-molding onto a metal tube.
In yet another embodiment the invention comprises a ground anchor system for
anchoring a post
comprising a base plate, a housing extending above the base plate, an anchor
extending below
srb'srb0196R
CA 02520080 2005-09-16
-4-
the base plate, the anchor comprising a tapered helix having a thread
encircling a tube which
tapers inwardly towards the lower end of the anchor, and a boring tip at the
lower end of the
anchor, wherein the helix begins at the base plate and ends above the end of
the boring tip a
distance of no more than 50% of the combined length of the anchor and boring
tip and tapers
S inwardly towards the lower end of the anchor at an angle of between 1 and 30
degrees relative to
the vertical plane, the thread has a constant angular pitch of between 3 and
30 degrees relative to
the horizontal plane and tapers from a first width proximal to the tube to a
second narrower
width distal to the tube, and the base plate, housing, anchor and boring tip
are manufactured by
extrusion.
In still another embodiment, the invention comprises a ground anchor system
for anchoring a
post comprising a base plate, a housing extending above the base plate, an
anchor extending
below the base plate, the anchor comprising a tapered helix having a thread
encircling a tube
which tapers inwardly towards the lower end of the anchor, and a boring tip at
the lower end of
the anchor wherein the helix begins at the base plate and ends above the end
of the boring tip a
distance of no more than 50% of the combined length of the anchor and boring
tip and tapers
inwardly towards the lower end of the anchor at an angle of between 1 and 30
degrees relative to
the vertical plane, the thread has a constant angular pitch of between 3 and
30 degrees relative to
the horizontal plane and tapers from a first width proximal to the tube to a
second narrower
width distal to the tube, and the base plate, housing, anchor and boring tip
are manufactured by
casting.
In yet another embodiment, the invention comprises a post anchoring system
comprising a base
plate, a housing extending above the base plate, an anchor extending below the
base plate, the
anchor comprising a tapered helix encircling a tube which tapers inward at its
lower end, a
boring tip at the lower end of the anchor, and a post inserted into the
housing, wherein the length
of the anchor is at least 25% of the length of the overall post anchoring
system.
In still a further embodiment, the invention comprises a method of inserting a
post anchor
comprising the steps of vertically positioning the post anchor in a selected
location with the tip of
the post anchor in contact with the ground surface, driving the post anchor by
driving means into
the ground to a position in which the thread of the helix of the post anchor
is in contact with the
ground surface, placing a lever arm in the housing of the post anchor,
simultaneously applying
s~~h~srbo ~ ~~a
i
CA 02520080 2005-09-16
-5-
sufficient downward pressure and rotational torque to the lever arm to rotate
the post anchor into
the ground to a position in which the base plate is in contact with the ground
surface, removing
the lever arm, and positioning and affixing a post into the housing of the
post anchor.
The driving means may comprise a drive shaft integrated with the lever arm.
Other aspects of the invention will be appreciated by reference to the
description of the preferred
embodiment which follows and to the claims.
Brief Description of the Drawings
The invention will be described by reference to the preferred embodiment and
the drawings
thereof in which:
Figure 1 is a perspective view of the ground anchor, according to the
invention;
Figure 2 is a plan view of the ground anchor, according to the invention;
Figure 3 is a cross-sectional view through line 3-3 of Fig. 2; and
Figure 4 is a perspective view of an installation, according to the invention.
Detailed Description of Best Mode and Preferred Embodiment of the Invention
As shown if Figs. 1, 2 and 3, an integrated ground anchor and post mount
housing device 2
comprises a housing 4 adjacent a base plate 6, the base plate adjacent an
anchor segment. The
anchor segment is a hollow tube 8- incorporating a helix 10 extending along a
portion of its
length, and a boring tip 12 at its lowermost end. The housing provides support
for a post or other
upright inserted therein. The base plate 6 connects the housing 4 to the
anchor segment and
defines the extent of insertion of the anchor into the ground. The anchor
segment helix 10 has a
wide and tapered thread 14 extending most of its length. The boring tip 12 is
narrowed, crimped
or cut to assist in the loosing of the soil for anchor segment insertion.
The length of the anchor segment preferably is at least 25% of the above
ground height of the
supported post. The hollow tube 8 may taper inwardly from the base plate
towards the boring tip
12. Refernng now to Fig. 2, the helical portion preferably begins at a
distance a above the
srblsr60196fi
CA 02520080 2005-09-16
-6-
bottom end of the anchor of between 10% and 25% of the total length of the
embedded portion
of the anchor. The helix is continuous and has a taper b which may be fixed or
may vary
between 1 and 20 degrees relative to the vertical plane, increasing in angle
from the terminus to
the base plate. The helix preferably terminates at a distance c below the base
plate. The angular
S pitch d of the thread 14 is preferably a constant angle of between 3 and 30
degrees relative to the
horizontal plane. As in a conventional screw, the thread preferably is
tapered, having a thicker
width proximal to the central vertical axis of the ground anchor and narrowing
distal to the
vertical axis.
The tapered helical thread of the anchor firmly engages with the ground into
which it is threaded
to provide a solid support to a post inserted in the housing. Helix taper and
length, and thread
taper and pitch may be selected to optimize retention and lateral support of a
post in a particular
ground type.
The base plate preferably is of a design and dimensions sufficient for
ensuring the lateral
stability of the anchoring system and of sufficient strength to support the
housing and anchor
1 S segments. The housing preferably provides support to the post and
surrounds the lower end of
the post on all sides for a distance of at least 10% of the overall length of
the post. The housing
may have solid walls 18, as shown in Fig. 1, or non-solid walls. For example,
as shown in Fig.
2, the non-solid walls 20 may have a plurality of openings to reduce material
requirements. One
or more inserts 22 may be used for the accommodation of posts having a
diameter smaller
diameter posts. The inserts may be placed between the post and the housing
walls to ensure a
close fit.
Post support in the housing may be enhanced by one or more of the following
mechanisms:
1. bolts or screws may be used to secure the post within the housing;
2. a threaded adaptor may be disposed on the base plate to permit the post to
be screwed
onto the base plate following anchor installation;
3. a plurality of fins may be integrated into the interior surface of the
housing;
4. the post may be selected or machined to fit snugly in the housing to
enhance friction
between the surfaces of contact of the post and the housing;
5. inserts may be fitted into the housing to permit the securing of smaller
posts.
srb~srb01968
CA 02520080 2005-09-16
In one embodiment, the post may be molded or extruded integrally with the
anchor to create a
monolithic post and anchor structure.
To permit egress of water which may collect in the housing, an opening 24 may
be provided
through the base plate 6 between the housing 4 and the hollow tube 8 of the
anchor segment to
allow for drainage of water.. This opening will also permit the escape of air
displaced by
insertion of the post into the housing.
Preferably, the ground anchor device is manufactured by extrusion, direct-
injection molding or
over-molding from plastic or corrosion-resistant metals such as aluminum. The
hollow post
design facilitates entry into the soil, adds to stability of the anchor in the
ground, allows for
drainage of water and equalisation of air pressure, and reduces material
costs.
The helix of the ground anchor permits the post to be reused, and provides for
increased lateral
stability and retention, particularly in loose soils. The presence of a wide
thread on the helix
provides greater stability to the anchor by increasing the surface area which
is contact with the
soil. The boring tip loosens soil to facilitate entry of the helical thread
into the ground.
An adaptable housing allows for different types of posts to be used in
conjunction with
the ground anchor, and facilitates maintenance and adaptation of the above-
ground portion of the
post as necessary. The base plate provides strength to the physical connection
between the
housing and the helical anchor and increases the lateral stability of the
anchor in the ground.
According to one embodiment of the method of the invention, a host may be
anchored into the
ground according to the following steps:
1. the boring tip of the anchor segment is driven or pushed into the ground
until the edge
of the first thread of the helix makes contact with the ground;
2. a lever arm or drive shaft is placed into the housing;
3. downward pressure and torque are applied to the lever arm or drive shaft to
screw the
anchor segment into the graund until the base plate makes contact with the
ground;
4. the lever arm or drive shaft'~is removed from the housing; and
srb'srb01968
CAI02520080 2005-09-16
_g_
5. a post is placed into the housing and affixed therein.
As shown in Fig. 4, a plurality of ground anchor and post mount housing
devices 2 may be
screwed into the ground surface until the base plates 6 are at the surface of
the ground. A post
26 may be inserted into the housing 4 of each anchor. In one embodiment,
anchored posts may
be joined by rails to form a fence which is easily removable and reusable.
It will be appreciated by those skilled in the art that other variations of
the preferred embodiment
may also be practised without departing from the scope of the invention.
srb~srb01968
