Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02691432 2009-01-28
WATER DRAINING FOOT MAT
FIELD OF THE INVENTION
[0001] The present invention relates generally to foot mats, and more
particularly to foot mats
for outdoor use that facilitate the removal of water from the surface of the
mat.
BACKGROUND OF THE INVENTION
[0002] Foot mats, which may be referred to as doormats and stair treads, are
often used in
households and workplaces to protect flooring or stepping surfaces from
residues being
transported under footwear. These mats often possess characteristics suited to
remove
particles from footwear and to provide a cushioning effect to a person's step.
[0003] Mats that are intended to be used outdoors should be able to function
adequately in the
presence of rain and snow. Typically snow will accumulate on a mat and make it
difficult to
use, and water may accumulate on a mat. Some mats incorporate heating elements
that
convert electricity to heat for the purpose of melting snow that falls on the
mat. However, this
requires an electricity source, paying for the electricity, and adds to the
cost of the mat.
[0004] Some mats have been disclosed with projections connected to the surface
of a base for
the purpose of allowing water to accumulate on the base while keeping the feet
of people
contacting the mat out of the water. These mats have been designed for use in
automobiles
and generally employ projections with a total cross-sectional area that is
large relative to the
total area of the mat, and generally provide for no way of draining water from
the mat other
than by evaporation or by lifting the mat. Such mats would not function well
in outdoor
conditions where they are exposed to rain and snow, as the snow and water
would accumulate
on the mat.
SUMMARY OF THE INVENTION
[0005] The invention relates to a foot mat for resting on a floor comprising
a. a base having a sloping draining surface for draining water, and
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b. a plurality of substantially regularly spaced projections connected to the
base
for supporting the weight of a person who steps on the mat,
wherein the total cross-sectional area of the projections is no more than one
quarter of
the total area of the draining surface.
[0006] The total cross-sectional area of the projections may be no more than
one eighth of the
total area of the draining surface.
[0007] The top ends of the projections may be substantially in a plane
parallel to the floor. At
least four projections may fall at least partially within any circle inscribed
on the draining
surface having a diameter of three inches. The projections may be cylindrical
and each have
approximately the same width which is at least one eighth of an inch and not
more than one
inch. Each projection may be separated from the nearest other projection by a
distance of at
least twice the diameter of the projections and not more than eight times the
diameter of the
projections, where the distance between projections is the distance between
the central
vertical axes of the projections.
[0008] The base may further comprise a water retaining wall extending
partially around the
edges of the base and have a water exit to permit water to run off the mat
through the water
exit.
[0009] The base may be substantially rectangular and have a front edge, a back
edge, a left
edge, and a right edge. The front edge may be higher than the back edge and
the draining
surface may be sloped to cause water to run off the back edge. The base may
further comprise
a water retaining wall extending partially around the edges of the base and
have a water exit
to permit water to run off the mat through the water exit. The water exit may
be a gap in the
water retaining wall on the front edge. The width of the water exit may be no
less than five
percent of the width of the front edge and no more than twenty-five percent of
the width of
the front edge.
[0010] The base may further comprise first and second water exits and wherein
the draining
surface is sloped to cause water impinging on a portion of the draining
surface to run towards
the first water exit and to cause water impinging on the other portions of the
draining surface
to run towards the second water exit.
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[0011 ] The draining surface may comprise particle retainers for slowing
removal of particles
on the draining surface. A particle retainer may be a depression in the
draining surface.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The present invention will now be described by way of example with
reference to the
following drawings.
[0013] Figure 1 is a perspective view of one embodiment of the invention
showing the upper
side.
[0014] Figure 2 is a perspective view of one embodiment of the invention
showing the lower
side.
[0015] Figure 3 is a partial view of the back edge of one embodiment of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0016] In a preferred embodiment shown in Figure 1, the foot mat includes a
base 1 with a
number of projections 2 connected to the base 1. The base 1 and projections 2
may be
integrally formed from the same substrate or may be elements that are formed
separately and
subsequently attached, for example using an adhesive or thermobonding process.
[0017] The base I is generally formed in a substantially rectangular shape
with the corners
rounded as shown in Figure 1, although other shapes are possible. If the base
1 is substantially
rectangular, one edge may be designated the front edge 7 and the opposite edge
the back edge
8, with the other two edges being referred to as the left and right edges.
[0018] The base I and projections 2 may be made of the same material, which
could be a
thermoplastic material such as thermoplastic polyurethanes of the polyether or
polyester type
or aliphatic polyurethane, or alternatively they may be made of a woven or non-
woven fabric
formed of synthetic or natural materials.
[0019] The foot mat is used by placing it on a substantially level surface, or
floor, such as the
surface of a porch outside the exterior door of a house, with the projections
2 on the upper
side and the underside of the base 1 resting on the floor, where the base is
adapted to lie in a
substantially flat position on the floor.
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[0020] The upper surface of the base 1, to which the projections 2 are
attached, is the draining
surface 3. The draining surface 3 is designed so that water may flow across
it. The draining
surface 3 is designed so that, for any given point on the draining surface 3,
the surface is
formed so that water that is placed on that point will flow to one of the
edges of the mat under
the force of gravity when the mat is resting on a floor. For example, the
draining surface 3
may be in a single plane which is higher at the front edge 7 than the back
edge 8 so that water
placed at any point on the draining surface 3 will flow to approximately the
closest point on
the back edge 8. Alternatively, for example, the draining surface 3 may have
its highest point
near the center of the base 1 such that the height of the base 1 above the
floor monotonically
decreases from that central point to each point on the edges.
[0021] In the preferred configuration shown in Figure 1, the mat has a water
retaining wall 4
which rises above the draining surface 3 along some parts of the edges of the
base 1. The
water retaining wall 4 shown in Figure 1 extends around all edges of the base
1 except for a
relatively small portion, which is referred to as a water exit 5. The width of
a water exit 5 may
be, for example, 5 to 25% of the length of one edge of the base 1.
Alternatively it could
extend along the entire extent of one edge. The base 1 is designed so that
water placed at any
point on the draining surface 3 will flow to a water exit 5. For example, if
the draining surface
3 is in a single plane that is higher at the front edge 7 than at the back
edge 8, then a water exit
5 may be positioned on the back edge 8 of the base 1. Alternatively multiple
water exits 5
may be employed, such as one at each end of the back edge 8.
[0022] The water retaining wall 4 is designed to guide water that flows to an
edge of the base
1 towards a water exit 5 under the force of gravity when the mat is resting on
a floor. The
slope of the draining surface 3 may be designed to direct water impinging on
one portion of
the draining surface 3 to one water exit and water impinging on other portions
of the draining
surface 3 to flow towards a different water exit 5. For example, the draining
surface 3 may be
highest near its center along a line extending from the front to the back edge
and slope down
towards both the right and left edges, with a water exit being located in each
of the right and
left edges. In that case, water impinging on a portion of the draining surface
3 nearer to the
left or right edge respectively will flow towards that edge.
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[0023] A water exit 5 on the back edge 8 of the base 1 can be seen more
clearly in Figure 3,
which shows a partial view of the front edge 8 including a water exit 5 in the
middle
corresponding to the water exit 5 shown in Figure 1. The water exit 5 in this
embodiment is a
gap in the water retaining wall 4. In other embodiments, a portion of the
draining surface 3 in
the neighbourhood of the water exit 5 could be designed to have a lower height
above the
floor with an increased slope to further facilitate the drainage of water.
[0024] It is not essential that the draining surface 3 be smoothly sloping as
long as the height
is substantially monotonically non-increasing from each point on the draining
surface 3 to an
edge, or to a water exit 5 if a water retaining wall 4 is used. For example,
the draining surface
3 could be stepped so that multiple steps form the slope that allows water to
drain.
[0025] In a preferred embodiment, the height of each projection 2, which is
the distance that
the highest point on each projection 2 extends above the draining surface 3,
may be designed
so that the highest points of all projections 2 within any circle
approximately three inches in
diameter are all located approximately in a plane so that they can
simultaneously engage with
a flat surface, such as the sole of a shoe, that is placed on top of them. In
the preferred
embodiment shown in Figure 1, the highest points of all the projections 2 are
approximately
in a single plane that is approximately parallel to the floor when the mat is
resting on a floor.
As seen in Figure 1, the heights of the projections 2 decrease as the
projections are further
away from the front edge 7 in proportion to their distance from the front edge
7 since the front
edge 7 is higher than the back edge 8 and the draining surface 3 is planar.
The height of a
projection may vary, for example, from as small as one eighth of an inch to as
much as one
and a half inches.
[0026] The material or materials used to construct the mat and minimum size
and number of
the projections 1 are selected so that any group of projections in any circle
approximately
three inches in diameter can support the weight of a person without causing
the highest points
of those projections to deviate substantially from being in a plane, so that a
person can step on
the mat while walking without significantly disrupting the person's movement.
This requires a
sufficient number of sufficiently large projections to be located within any
given area.
[0027] For example, a typical configuration as exemplified by Figure 1 would
have the
projections attached in a grid configuration where each projection is
cylindrical, with a
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vertical axis substantially perpendicular to the floor or to the draining
surface 3. The width of
a projection 2 is the maximum width of any cross section through the
projection 2 taken
parallel to the floor when the mat is resting on the floor. Each projection 2
may have a width
of approximately one eighth of an inch to one inch with a spacing of
approximately two to
eight times the width of the projections between the vertical axes of adjacent
projections 2,
but constrained so that at least four projections 2 are at least partially in
any circle inscribed
on the draining surface 3 that is three inches in diameter. A fixed spacing,
so a fully regular
pattern is formed, and projections of the same size are preferred to simplify
the manufacturing
of the mats and optimize the use of material.
[0028] The spacing of the projections 2 is designed so that when snow is
falling on the mat it
will fall between the projections 2 on to the draining surface 3 where it will
melt and then the
resulting water will run across the draining surface 3 to an edge or a water
exit 5. Melting of
snow may be facilitated by sunlight or by a melting agent, such as salt, that
is placed on the
draining surface 3. In order to facilitate the operation of the mat when it is
snowing, the sum
of the cross-sectional area of the projections 2 should be no more than one-
quarter of the total
area of the draining surface 3, or of the mat, and preferably less than one-
eighth of the total
area.
[0029] The projections 2 also serve to help remove material attached to the
bottom of a shoe,
such as mud and snow.
[0030] Alternatively other shapes of projections 2 may be used, such as
conical, frusto-
conical, cylindrical, ovoid, hemispherical or polyhedral shapes. The tops of
the projections 2
may be flat or alternatively may be rounded, which helps to prevent the
accumulation of snow
and other particles on top of the projections 2.
[0031] The projections 2 may be made of a rigid material or alternatively may
be formed from
a compressible material that substantially returns to an uncompressed
configuration following
compression to provide a cushioning effect. The projections 2 may be hollow or
solid, or
partially hollow, and need not be made solely of a single material. For
example, to provide a
superior cushioning effect, each projection 2 could comprise a base portion
connected directly
to the draining surface 3 and a spring portion being the upper portion of the
projection 2. The
base portion may be a relatively incompressible material and the spring
portion relatively
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compressible. The spring portion may be a hollow truncated cone of a diameter
less than that
of the base portion and which deflects in the direction of the draining
surface 3. For example,
the spring portion may be a belleville spring.
[0032] The underside of the base 1 may be solid and flat, or it may
alternatively employ a
number of surfaces which lie in a single plane and are distributed across the
length and width
of the base 1 so that when they are in contact with the floor, the mat rests
in a stable position
on the floor. Figure 2 shows the underside of one embodiment of the invention
that employs a
grid of relatively thin ribs 100. The embodiment shown in Figure 2, like that
shown in Figure
1, has a front edge 7 that is higher than the back edge 8 with a planar
draining surface 3 for
directing water towards the back edge 8. In this design, the draining surface
3 is the upper side
of a relatively thin layer of approximately uniform thickness with the ribs
100 varying in
height so as to achieve a suitable slope for draining water. In the design
shown, the ribs 100
decrease in height proportionally to their distance from the front edge 7.
[0033] The mat may optionally further include particle retainers. A particle
retainer is a
modification of the draining surface 3 that is designed to retain solid
particles on the draining
surface 3. For example, these may be used to slow the removal of salt from the
draining
surface 3 that has been put on the draining surface 3 to help melt snow. One
form of particle
retainer shown in Figure 1 comprises a shallow depression 6 in the draining
surface 3. Such
depressions 6 may retain some particles as well as some water with dissolved
particles which
may evaporate and leave the dissolved material in the depression 6.
Alternatively, ridges
oriented across the path of flowing water on the draining surface 3 may be
employed. For
example, in a configuration with a planar draining surface 3 sloping from the
back edge 7
down to the front edge 8, ridges parallel to the front and back edges could be
employed that
span the width of the mat.
[0034] The foregoing are specific examples of certain aspects of the present
invention. Many
other embodiments, including modifications and variations thereof, are also
possible and will
become apparent to those skilled in the art upon a review of the invention as
described herein.
Accordingly, all suitable modifications, variations and equivalents may be
resorted to, and
such modifications, variations and equivalents are intended to fall within the
scope of the
invention as described herein and within the scope of the appended claims.
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