Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02369256 2002-O1-24
CURBING POR PAVING S'IfONES
The present invention relates to the provision of curbing for paving stones in
general,
and in particular to an extruded plastics curbing which exhibits strong
rigidity when required
but which also can be rendered flexible if necessary.
Background of the Invention
Paving stones are used in landscaping situations, for decorative walkways,
garden
paths, laneways, patios and other projects. The paving stones can be
rectangular or square,
they can included both rectangular and square sections, and they can also
include hexagonal
and other polygonal shapes, including arcuate edges. The stones usually will
be placed in the
desired location, usually on a bed of crushed stone and sand, in a preordained
pattern as
established by the landscape architect. The resulting project may include
straight edges only,
arcuate edges only, or a combination of straight and arcuate edges. In order
to maintain the
edges in the desired position for many years it is known to use curbing,
located below the
upper surface of the paving stones, to define the desired edges of the project
and to hold the
outer peripheral course of paving stones in position, thereby preventing or at
least inhibiting
any movement of the outer peripheral course relative to the remaining paving
stones of the
project.
US Patent No. 5,375,941 dated December 27, 1994 and issued to Strobl, Jr. et
al is
illustrative of known curbing designs as currently available. The curbing
design of that patent
includes a vertical leg against which the paving stones will abut, a plurality
of "belts"
extending perpendicularly to the vertical wall at the bottom edge thereof, a
triangular buttress
connected to each belt and to the vertical wall for strengthening purposes, an
annular boss
in the middle of each buttress for reception of an anchoring nail, and a
"capping strip"
extending parallel to the vertical leg and connecting the free ends of the
belts together along
the length of the curbing. The curbing is injection moulded from a plastics
material and
includes means at each end for interlocking separate lengths together to
create longer
sections of curbing. The curbing as described above i.s intended to support
paving stones
along a straight edge thereof. In order to support paving stones along an
arcuate edge the
capping strip can be severed between one or more pairs of belts to permit
flexure of the
vertical leg.
While the above-described curbing serves its purpose it is expensive to
manufacture
and it can be manufactured only in specified lengths, depending on the size of
the dies that
can be made. Several lengths of curbing may be required to support an edge of
paving stones
that is longer than the longest available length of curbing. The strength of
the joint between
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adjacent lengths will not be as great as that of the main body of the curbing.
Furthermore,
if the capping strip is cut at several places between adjacent belts, the
resulting curbing will
not only be flexible, to accommodate arcuate edges, it could be too flexible
and difficult to
handle, making it very difficult to position the curbing properly on its base.
Once the capping
strip has been cut it is almost impossible for the cut length of curbing to
still be used to
support paving stones properly along a straight edge.
Summary of the Invention
The present invention overcomes the problems associated with the prior art as
exemplified by the above-described US patent. The curbing of this invention
can be extruded
from suitable plastics material and then cut to any desired length, obviating
the need to join
short lengths of curbing together. It includes integrally formed vertical and
base leg portions
giving the curbing a generally L-shape in cross-section. It includes a third
leg portion which
is joined to the vertical leg portion by way of a flexible or living hinge and
which terminates
at an end projection which is adapted for engagement with a corresponding
portion of the
base leg portion. When the third leg is engaged with the base leg along the
length thereof
the curbing is extremely rigid longitudinally, meaning that it will establish
and support a very
straight edge of the paving stones. The third leg need not be engaged with the
base leg
portion of the curbing and if it is not engaged the curbing will be capable of
a certain degree
of flexure for gentle arcuate edges. The base leg portion can be cut at set
locations along the
length thereof to create relatively short sections of base leg portion,
thereby allowing greater
flexibility of the vertical leg portion to accommodate paving stone edges
which are more
sharply arcuate. Zig-zag or angled edges can be accommodated if the base leg
portion and
the third leg portion are cut at the corners established by straight edge
sections of the paving
stones and the third leg portion is engaged with the base leg portion along
each length of
curbing. If the third leg portion is- selectively disengaged from the base leg
portions then a
combination of straight and arcuate sections of a long length of curbing can
be defined.
The base leg portion preferably has a plurality of openings therethrough to
accept
anchoring pins or nails. It also preferably has a plurality of larger openings
therethrough for
the reception of soil or vegetation (grass) which will help to cover the
curbing and will also
help to anchor it to the underlying base.
In summary of the foregoing, therefore, the present invention may be broadly
considered as providing curbing for use in aligning and positioning paving
stones comprising:
an elongated generally L-shaped member having a vertical alignment leg portion
and
a base leg portion extending generally perpendicularly from a bottom edge of
the vertical leg
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portion; means defining a living hinge with the vertical leg portion adjacent
an upper edge
thereof: means defining a locking edge connected to the base leg portion, the
locking edge
being parallel to, spaced from, and facing the vertical leg portion and also
being parallel to and
spaced above the base leg portion; and a third leg portion connected to the
living hinge for
pivotal motion relative to the vertical leg portion, the third leg portion
terminating at a
projection positioned along the free longitudinal edge thereof, the projection
being adapted
for snap engagement with the locking edge.
Brief Descriution of the Drawings
Figure 1 is a perspective view of a length of curbing for paving stones in
accordance
with this invention.
Figure 2 is an end view of the curbing of the present invention.
Figures 2A and 2B show enlarged partial views of two forms of living hinge
usable with
the present invention.
Figure 3 is a top plan view of a length of curbing in accordance with the
present
invention.
Figure 4 is a top plan view of a length of curbing with cut out zones in the
base leg
portion.
Figure 5 shows an end view of the curbing of this invention in abutment with a
paving
stone.
Figure 6 shows an end view of two lengths of curbing interlocked for shipping
or
storage.
Figure 7 is a top plan view showing, somewhat schematically, how the curbing
might
be arranged to define a concave edge for the paving stones.
Figure 8 is a top plan view showing, somewhat schematically, how the curbing
might
be arranged to define a convex edge for the paving stones.
Description of the Preferred Embodiment
Figure 1 provides a perspective view of a length of curbing 10 in accordance
with the
present invention, it being understood that the figure is intended to show a
piece of curbing
generally of indefinite length, notwithstanding that production pieces will
likely be available
in standard lengths of 4, 6, 8, 10 and 12 feet or 1, 2, 3 or 4 meters. The
curbing 10 is
extruded lengthwise from a suitable wear resistant material such as
polyvinylchloride (PVC).
The curbing 10 is generally L-shaped in end view or transverse cross-section,
with a
generally vertical first leg portion 12 and a generally horizontal base leg
portion 14 which
projects from the bottom edge of the vertical leg portion. )<n the preferred
embodiment the
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base leg portion has a longitudinally extending, generally rectangular raised
ridge portion 16
which has a flange 18 projecting towards the vertical leg portion 12 from the
forward edge of
the uppermost surface 20 thereof. Adjacent it free outer edge the base leg
portion i4 has a
pair of upstanding, transversely spaced apart walls 22, 24 with the wall 24
extending valong
the free outer edge of the base leg portion and being shorter in height than
the other wall 22.
The wall 22 includes a short hook or flange 26 projecting towards the free
outer edge of the
base leg portion. The uppermost free edge of the vertical leg portion 12
includes a vertically
extending wall or flange 28 spaced slightly inwardly therefrom, defining a
longitudinally
extending flat shoulder portion 30.
i0 Below the shoulder portion 30 the vertical leg portion 12 is provided with
a
longitudinally extending inwardly projecting flange 32 which terminates at an
integrally
formed or "living" hinge 34 defined by a reduced thickness of the extrudate.
The hinge 34 is
connected to a third leg portion 36 of the curbing, which leg portion
terminates along it free
edge at a latch section 38. The latch section 38 comprises an essentially U-
shaped trough 40
connected at one end to the third leg portion 36, with one edge 42 being free
and
unconnected. The living hinge 34 permits a certain degree of flexure of the
third leg portion
36 relative to the flange 32. The living hinge 34, as indicated above, is
formed from a
reduced thickness of the material which forms the flange 32 and the third leg
portion 36. The
thickness reduction can be achieved by way of opposing grooves 44, 46 in the
upper and lower
surfaces of the flange 32 as seen in Figure 2A or by way of a V-shaped notch
44' in the upper
surface of the flange 32 as seen in Figure 2B.
The ridge 16 is provided along its length with a plurality of equally spaced
apart
through holes 48, preferably circular in configuration. These holes or
openings are relatively
small in diameter and are intended to receive anchoring pins or nails
therethrough, to be
driven into the underlying ground.
The zone 50 of the base leg portion between the ridge 16 and the wall 22 is
provided
with a plurality of equally spaced apart though holes 52 of relatively large
diameter. These
holes or openings are intended to receive dirt, gravel, etc. of the overlying
ground and to also
permit grass or other plant material to pass roots therethrough for further
anchoring of the
curbing.
Another feature of the curbing of this invention is shown in Figures i and 4,
wherein
it is seen that the base leg portion 14 is provided with at least one
transverse cut-out 54
which extends from the outer free edge of the base leg portion inwardly to
adjacent the
vertical leg portion 12. The purpose of this cut-out will become apparent from
the following
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description.
Figure 5 illustrates curbing 10 as it would be used in a landscaping
application. In this
case the curbing 10 is laid on a bed of earth and gravel B that has been
previously graded to
the desired level and compacted to accept the paving stones S. The curbing is
located at the
desired position and pins or anchoring nails P are driven through the
anchoring holes 48 to
hold the curbing in position. The paving stones S are laid with the first
course S-1 laid against
the vertical leg portion 12 of the curbing. The remaining courses can then be
laid as desired.
Once the patio, laneway or whatever has been laid and the contractor is
satisfied, the
remaining backfiil F of earth and gravel, if desired is laid over the exposed
curbing. Sod could
also be laid over the curbing to hide it from view. Earth or the roots of
grass can penetrate
the curbing through the larger holes 52 to help anchor the curbing in place.
Figure 6 illustrates how lengths of the curbing of this invention can be
interlocked
together for storage or transport. It is seen that a first length IO' of
curbing is inverted
relative to a second length 10 and the vertical wall 28 of tree second length
10 is positioned
in the space between the walls 22' 24' of the first length 10' while the
vertical wall 32' of the
first length 10' is positioned in the space between the walls 22, 24 of the
second length 10.
The hooks 26', 26 of the first and second lengths lock with the corner of the
vertical wall 28,
28' respectively to hold the lengths together. The inherent flexibility of the
polyvinylchloride
material from which the curbing is made allows the walls to flex sufficient to
permit the
lengths to be interlocked and to allow them to be separated without damage.
Figures 7 and 8 illustrate somewhat schematically how the curbing of this
invention can
be adapted to create an arcuate perimeter for the paving stones. It will be
appreciated that
all details of the curbing, as for example shown in Figures 1 - 4, are not
illustrated in Figures
7 and 8 for the sake of simplifying the presentation.
Figure 7 shows the curbing defining a concave edging for the paving stones. In
this
case the third leg portion 36 is cut generally transversely in the field
centrally of each cut-out
54. By doing this the only connection between adjacent sections 10-1, 10-2, 10-
3 of the
curbing 10 are the bridging sections 12-1, 12-2 of the vertical leg portion
12. The material
of the curbing is sufficiently flexible to allow each section 10-1, 10-2, 10-3
to be bent relative
to its adjacent section to create the arcuate shape as shown. In the field the
contractor would
fix the first section 10-1 in place, anchoring it with pins or nails and he
would then move the
second section 10-2 to its desired location relative to the first section,
anchoring it in place
when it is at the correct location. The same would then be done with the third
section 10-3.
Of course, any length of curbing could have as many sections as required to
fit the
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landscaping architects plans. Also, if a tighter curve than is possible with
the factory-installed
cut-outs 54 is required the contractor could manually cut the curbing to
create additional cut-
outs 54 along the length of the curbing.
Figure 7 shows the third leg portion 36 locked with the flange 18 of the
raised ridge
16 to give each section additional rigidity. This results in the arcuate edge
being formed as
a plurality of straight sections, as defined by the sections 10-1, 10-2, 10-3,
joined by the
shorter bridging sections 12-1, 12-2 of the vertical leg portion 12. The third
leg portion 36
could be removed completely from the curbing by cutting the leg portion from
the flange 32
along the living hinge 34. This would reduce the rigidity of the vertical leg
portion 12,
allowing an extra degree of flexibility, to help smooth out the arcuate edge.
Figure 8 illustrates a convexly arcuate edge formed in essentially the same
manner as
the concavely arcuate edge shown in Figure 7. The only major difference is
that the third leg
portion 36 must be cut more drastically at each cut-out 54 so that when the
sections 10-1,
i0-2, 10-3 are bent towards each other, rather than away from each other, the
cut ends of
the third leg portion will not interfere with each other. As indicated above,
the third leg
portion at the cut-outs would be cut at the hinge 34 as well as transversely
to remove a
section thereof at each cut-out 54.
Figures 7 and 8 illustrate dramatically the flexibility in the curbing
achievable by using
the cut-outs 54. If only straight curbing is required then the cut-outs 54
need not be provided
at all. Such a length of curbing is shown in Figure 3, representing a more
basic embodiment
of the present invention.
The ends of each length of curbing are cut straight across as there is no need
to
provide separate or integral means for interlocking consecutive lengths of
curbing together.
The anchoring thereof in place by pins, nails and/or earth and gravel is
sufficient to establish
the desired edge for the paving stones.
The curbing of the present invention is easy to manufacture by conventional
extrusion
techniques and it can be produced in any desired length depending on the
particular project
with which it will be used. It can be customized in the field as desired,
simply by cutting with
a sharp knife or cutting snips. It can be laid quickly and easily and the
third leg portion,
integrally formed during manufacture, allows the curbing to have extraordinary
rigidity,
especially when it is used to define a straight edge for the paving stones.
The foregoing has described a preferred form of the present invention. It is
understood
however that a skilled individual could modify the invention without departing
form the spirit
thereof as set forth in the claims appended hereto.
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