Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02542371 2006-04-04
TITLE OF THE INVENTION
POST ANCHOR
FIELD OF THE INVENTION
This invention relates to post anchors of a type used to secure a support post
for a
structure, such as a deck, fence or other structure requiring vertical or
horizontal support
posts.
BACKGROUND OF THE INVENTION
One form of post anchor according to the prior art comprises a base with four
upstanding
sidewalls and means such as screws to attach the post anchor to a post within
the cavity
defmed by the sidewalls. Such a post anchor is described in U.S. Patent No.
6,729,089
issued May 4, 2004 to Spragg.
One difficulty encountered with prior art post anchors is that water, such as
rainwater,
tends to run down the post and collect at the base, inside and around the post
anchor
cavity. Standing water or simply contact with wet ground around or inside the
base of a
post may cause the anchored post to rot, warp or corrode or may otherwise
damage the
post. Damage to the post may then destabilize any structure supported by the
post.
If the post anchor is made of metal, standing water inside or around the post
anchor
cavity may also corrode the base and sidewalls of the post anchor, eventually
leading to
failure and destabilization of the supported structure. For this reason, it is
known to
provide a coating to the post anchor to prevent corrosion.
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However, an additional difficulty with prior art post anchors is that,
particularly in the
case of a wood post, the post tends to absorb water and will accordingly
swell, or the post
may simply shorten and expand over time under the weight of the structure
being
supported. In both cases, the post circumference increases and exerts excess
pressure
from inside the cavity of the post anchor. This pressure may deform the post
anchor, and
may also cause any corrosion-resistant coating to crack. Under repeated
swelling cycles
as the post gets wet, then dries off, the cracked corrosion-resistant coating
will peel or
flake off and the post anchor itself will also eventually fail. Apart from the
coating
io failure, a prior art post anchor may still fail under repeated post
swelling cycles, due to
fatigue in the post anchor material from the changes in pressure exerted by
the post.
Exposure to elements besides water can also cause difficulties, as ultraviolet
rays may
cause the post anchor material to break down and eventually fail. It is
therefore desirable
to provide a post anchor with some protection from ultraviolet rays.
Aesthetically, it is often preferable to use a post anchor with an appearance
that blends
into that of the post being supported, and/or into the ground or surface on
which the post
anchor is mounted.
It is therefore an object of the invention to provide an improved post anchor
which
overcomes the above limitations and provides other desirable features.
This and other objects of the invention will be appreciated by reference to
the summary
of the invention and to the detailed description of the preferred embodiment
that follow.
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SUMMARY OF THE INVENTION
According to one aspect of the invention, the post anchor is made from a
thermoplastic
polymer such as polyethylene, preferably with additives to enhance the
ultraviolet
resistance of the polymer. The polymer is textured to provide a grainy
appearance,
similar to a wood grain or other natural grain.
In another aspect of the invention, channels are provided on the inside upper
surface of
the base inside the post anchor to allow water to flow toward a drain hole
extending
io through the center of the base. The base of the post anchor is elevated off
the ground by
shallow feet or extensions to allow the circulation of air or water under the
post.
In yet another aspect of the invention, interior ribs extend medially along
the vertical
extent of each wall to limit deformation of the post anchor under pressure
from the post
as it expands.
In a further aspect of the invention, the corners of the post anchor may be
thicker than the
walls, thereby strengthening the post anchor and reducing the chance of
failure due to
expansion of the post inside the post anchor.
In one aspect, the invention comprises a post anchor, having a base with an
upper surface
and an underside and a plurality of upstanding sidewalls supported on the
upper surface
of the base and defining a cavity, where each sidewall abuts two other
sidewalls to form
two corners and there is an increased thickness about each of the corners. The
increased
thickness may be exterior to the cavity.
In another aspect, the invention comprises a post anchor, having a base with
an upper
surface and an underside, a plurality of upstanding sidewalls supported on the
base and
defming a cavity, and one or more interior ribs on each sidewall. In a more
particular
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aspect, there may be two interior ribs spaced along the sidewall, and the ribs
may extend
perpendicularly to the base.
In yet another aspect, the invention comprises a post anchor, with a base
having an upper
surface and an underside, a plurality of upstanding sidewalls supported on the
upper
surface of the base and defming a cavity, at least one drain hole extending
through the
base and a plurality of channels on the upper surface of the base, the
channels
communicating with the drain hole.
io In another aspect, -the invention comprises a post anchor, having a base
comprising an
upper surface and an underside and a plurality of upstanding sidewalls
supported on the
upper surface of the base and defining a cavity, and a plurality of supports
depending
from the underside of the base. The supports may comprise an extension at each
corner.
is In another aspect, the invention comprises a post anchor, having a base
comprising an
upper surface and an underside and a plurality of upstanding sidewalls
supported on the
upper surface of the base and defming a cavity, a plurality of supports
depending from
the underside of the base, each of the sidewalls abutting two other sidewalls
to form two
corners, wherein the sidewalls have an increased thickness about each of the
corners and
2o each sidewall further comprises one or more interior ribs, and the base has
at least one
drain hole extending through the base and a plurality of channels on the upper
surface of
the base, the channels communicating with the drain hole.
In a further aspect of the invention, the base and sidewalls may be made of a
25 thermoplastic polymer. The polymer may be polyethylene and may further
contain an
ultraviolet resistant additive blended with the polyethylene. In yet a further
aspect, the
polymer may have a textured surface.
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The foregoing was intended as a broad summary only and of only some of the
aspects of
the invention. It was not intended to defme the limits or requirements of the
invention.
Other aspects of the invention will be appreciated by reference to the
detailed description
of the preferred embodiment and to the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The preferred embodiment of the invention will be described by reference to
the
io drawings in which:
Fig. 1 is a perspective view of the post anchor according to the preferred
embodiment;
Fig. 2 is an elevation view thereof;
Fig. 3 is a top view thereof;
Fig. 4 is a sectional view along line 4- 4 of Fig. 2;
Fig. 5 is a bottom view of the post anchor according to the preferred
embodiment;
and
Fig. 6 is an exploded perspective view of the post anchor and a post according
to
the preferred embodiment.
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DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
OF THE INVENTION
Fig. 1 is a perspective view of a preferred embodiment of the post anchor 2.
The post
anchor 2 is preferably made of a thermoplastic polymer, such as polyethylene,
which is
easy to form to the proper shape, corrosion-resistant, waterproof, strong,
lightweight, and
relatively inexpensive. The polyethylene surface can also be worked during the
forming
process to provide a rough, grainy texture, similar to the wood posts which
the post
anchor may support. Polyethylene is also available in many colours, which can
be mixed
io to provide or enhance the appearance of an irregular, grainy surface, or
otherwise
selected to blend into the area where the post anchor is being used. Finally,
polyethylene
is easily modified to include additives, such as ultraviolet protectors, which
may be
useful for outdoor applications.
Post anchor 2 comprises a base 4, supporting four upstanding sidewalls 6,
which define a
cavity 8. Walls 6 may be placed anywhere on base 4, to provide a cavity 8 of
various
dimensions, such as 4" X 4" or any other desired size and shape to accommodate
various
posts. Walls 6 are preferably spaced inward from the edges 10 of base 4, to
leave space
for attachment holes 12 near the edges 10. Screws or other fastening devices
may be
inserted into attachment holes 12 to secure the post anchor 2 to a deck, floor
or any other
suitable support.
Walls 6 intersect at corners 16, which may comprise a thicker layer 17 of
material as an
external augmentation method to strengthen the post anchor 2 at the corners of
cavity 8.
It will be understood that other reinforcing methods may also be used to
strengthen the
post anchor 2 in the corners 16 where walls 6 intersect.
As best shown in Fig. 3, each wall 6 may also include one or more interior
ribs 15 to
provide expansion space in cavity 8 for an inserted post to swell. Each wall
preferably
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contains a pair of interior ribs 15. The maximum size of the post which may be
inserted
into cavity 8 is normally defmed by the front faces 19 of each interior rib
16, as
illustrated by the dotted line in Fig. 4. However, the post anchor 2 provides
expansion
room for the post in spaces 21 in the center of each wal16 between the
interior ribs 15.
Further expansion room is available in spaces 23 in the corners of the cavity
8.
As best seen in Fig. 2, each wall 6 may contain a hole 14, into which a screw
or other
fastening device may be inserted to secure a post (not shown) in cavity 8.
Base 4, which
is best seen in Fig. 3, may also comprise one or more holes 22, through which
screws or
io other fastening devices may be inserted from the underside of base 4 to
secure a post (not
shown) in cavity 8.
The upper surface of base 4 inside cavity 8 contains one or more interior
channels 18.
Base 4 also includes a drain hole 20. Water that accumulates inside the cavity
8 will
collect in an interior channel 18 and eventually drain out of the cavity 8
through the
network of interior channels 18 and drain hole 20.
The underside of base 4 is best shown in Fig. 5. Around each attachment hole
12, or at
any other suitable location, an elevated support 24 removes the post anchor 2
from direct
contact with the surface to which the post anchor is attached. This allows
better drainage
of water through drain hole 20, as well as allowing air and water to circulate
underneath
the base 4. This keeps the post and post anchor 2 away from shallow puddled
water and
allows the underside of the post and post anchor 2 to dry faster, if they do
get wet.
Preferably the elevated supports 24 are shallow extensions or feet.
Fig. 6 shows the post anchor 2 as it would be assembled with a post 26. Post
26 is
inserted in cavity 8 and screws or other fastening devices 28 are inserted
through holes 14
and 22 to secure the post within the cavity 8. The post anchor 2 and the post
26 may then
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be secured to any suitable surface by insertion of screws or other fastening
devices 30
through attachment holes 12 in base 4.
It will be appreciated by those skilled in the art that other variations to
the preferred
embodiments described herein may be practised without departing from the scope
of the
invention, such scope being properly defmed by the following claims.
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