U.S. patent application number 10/037911 was filed with the patent office on 2003-05-15 for vertical to horizontal draining synthetic turf.
Invention is credited to Daluise, Daniel A..
Application Number | 20030092531 10/037911 |
Document ID | / |
Family ID | 21897014 |
Filed Date | 2003-05-15 |
United States Patent
Application |
20030092531 |
Kind Code |
A1 |
Daluise, Daniel A. |
May 15, 2003 |
Vertical to horizontal draining synthetic turf
Abstract
Vertical to horizontal draining system and a synthetic turf
having such a system. The draining system of the present invention
prevents water from accumulating on the turf surface, which could
cause the top-dressing layer to "float" and be moved by water
inundation. The draining system of the present invention also
obviates the need for extensive excavation, underdrain systems and
free-draining replacement materials. The draining system of the
present invention incorporates a dynamic drainage blanket,
preferably sandwiched between two permeable porous geosynthetic or
non-woven materials. The synthetic turf system of the present
invention allows the use of an infilled synthetic turf over
impermeable or semi-permeable surfaces, including impermeable
soils, asphalt and concrete without having to remove such
surfaces.
Inventors: |
Daluise, Daniel A.;
(Southboro, MA) |
Correspondence
Address: |
Kevin S. Lemack
Nields & Lemack
176 E. Main Street
Westboro
MA
01581
US
|
Family ID: |
21897014 |
Appl. No.: |
10/037911 |
Filed: |
November 9, 2001 |
Current U.S.
Class: |
482/1 ;
472/92 |
Current CPC
Class: |
E01C 13/083 20130101;
A63C 19/04 20130101; E01C 13/08 20130101; E01C 13/02 20130101 |
Class at
Publication: |
482/1 ;
472/92 |
International
Class: |
A63C 019/04 |
Claims
What is claimed is:
1. A synthetic turf comprising: a sub-surface layer; a drainage
blanket over said sub-surface layer, said drainage blanket
comprising fused entangled filaments sandwiched between permeable
fabric; a pile fabric over said drainage blanket; and an infill for
said pile fabric.
2. The synthetic turf of claim 1, wherein said infill comprises
non-resilient particles.
3. The synthetic turf of claim 2, wherein said drainage blanket
extends into a trench drain.
4. The synthetic turf of claim 1, wherein said pile elements
comprise polyethylene.
5. The synthetic turf of claim 1, wherein said drainage blanket
further comprises a permeable geotextile fabrics sandwiching a core
which allows for the free flow of water.
6. The synthetic turf of claim 5, wherein said pile fabric is
tufted to a backing, said backing comprising two fibrillated outer
woven layers enclosing an open weave, dimensionally stable center
layer.
7. A method of creating a playing field formed of a synthetic turf,
comprising: forming a sub-surface layer; positioning a drainage
blanket over said sub-surface layer, said drainage blanket
comprising fused entangled filaments sandwiched between permeable
fabric; positioning a pile fabric over said drainage blanket;
providing an infill for said pile fabric; providing a drainage
trench for draining water away from said playing field; and
creating a path for the flow of water from said drainage blanket to
said drainage trench.
8. The method of claim 7, wherein said path is created by extending
said drainage blanket into said drainage trench.
9. The method of claim 7, wherein said drainage trench includes a
perforated pipe.
10. The method of claim 7, further comprising forming lines in said
playing field by tufting a portion of backing material and leaving
abutting portions of said backing untufted, and adhering said
untufted portions to said pile fabric.
Description
BACKGROUND OF THE INVENTION
[0001] Artificial turf has long been used in athletic venues. It is
a general object of such surfaces to mimic natural grass turfs
while eliminating the high maintenance required and poor durability
of natural surfaces. Artificial turf filled with a mixture of sand
and rubber has been shown to reduce the potential for certain
turf-induced injuries by greatly reducing abrasion. For example,
U.S. Pat. No. 4,337,283 discloses an artificial turf comprising a
subsurface, a pile fabric having a flexible backing on the
subsurface, and a compacted top-dressing layer comprising a mixture
of from 25 to 95 volume percent resilient particles such as rubber,
and from 5 to 75 volume percent fine sand. The top-dressing layer
is interspersed among the pile elements of the pile fabric and on
the backing. The purpose of the top-dressing layer is to stabilize
the pile elements, prevent graininess (i.e., prevent the tendency
of the pile fabric to lay in a given direction), absorb shock, and
improve the footing of a player running or walking across the
surface. Although the use of fine sand in the top-dressing layer
adds weight and reduces sponginess to the pile fabric layer and is
less abrasive than "large" sand, it still suffers from undesirable
abrasiveness. Moreover, the sand has a much higher specific gravity
than the rubber, and thus the two materials tend to separate and
cannot be kept in a uniform mix or be spread uniformly over the
area of a field. After installation, the lighter rubber material
rises to the top.
[0002] One problem encountered with the use of synthetic turfs is
adequate water drainage. Conventional turf systems rely on gravity
and the slope of the sub-base for water drainage. Playing surface
flooding can not only render the surface non-functional, but also
can cause dislodgement and movement of the infill materials. U.S.
Pat. No. 5,976,645 discloses methods for installing vertically
draining infilled synthetic turf systems which rely on extensive
sub-surface construction to protect the playing surface and infill
from water inundation. Previous systems relied on the installation
of 6 to 18 inch open graded, free draining stone base in
conjunction with an underdrain conduit system. Because of the
excavation required, the removal of materials and the placement of
new materials, such stone base systems significantly add to the
cost of installing the synthetic turf.
[0003] It therefore would be desirable to provide a synthetic turf
that exhibits excellent water drainage without requiring the
excavation, material removal, free-draining replacement materials
and complex underdrain system previously thought necessary.
[0004] It also would be desirable to provide a drainage system for
a synthetic turf that can be installed faster and more economically
than previous vertically draining systems.
SUMMARY OF THE INVENTION
[0005] The problems of the prior art have been overcome by the
present invention, which marries a vertically draining synthetic
turf system to a horizontal underdrain system. The draining system
of the present invention prevents water from accumulating on the
turf surface, which could cause the top-dressing layer to "float"
and be moved by water inundation. The draining system of the
present invention also obviates the need for extensive excavation,
underdrain conduit and free-draining replacement materials. The
draining system of the present invention incorporates a drainage
blanket, preferably sandwiched between two permeable porous
geosynthetic or non-woven materials.
[0006] The synthetic turf system of the present invention allows
the use of an infilled synthetic turf over impermeable or
semi-permeable surfaces, including impermeable soils, asphalt and
concrete without having to remove such surfaces.
BRIEF DESCRIPTION OF THE DRAWING
[0007] FIG. 1 is a cross-sectional view of the artificial turf in
accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0008] Turning now to FIG. 1, there is shown generally at 10 a
synthetic turf having a sloped sub-surface base 2 layer. The
subsurface base 2 is pre-existing; no excavation need be performed
unless a proper grade (to a tolerance of about 1/2" per 10 feet)
must be established. Preferably the slope of the sub-surface base 2
is 0.5% to about 1% from the field centerline in order to
facilitate drainage, and the sub-base is compacted to the maximum
practical density of the existing soils to form a firm and stable
surface. Conventionally, the sub-surface layer had to be excavated
and made permeable by the introduction of gravel or the like, which
required materials and labor. The present invention obviates this
need.
[0009] Positioned over the sub-base layer 10 is a dynamic drainage
blanket 12. The drainage blanket 12 is composed of a stiff,
non-degradable, non-obstructive (to the flow of water) material.
The blanket should be capable of evacuating at least 2 inches per
hour of rainfall from the entire playing area of the turf, even
with the minimum gradient (slope) of 0.5%. One preferred material
is Enkadrain.RTM., such as Enkadrain.RTM. 9812, commercially
available from Colbond, Inc., which is a high density polyethylene
core of fused, entangled filaments and a geotextile fabric bonded
to two sides. The tangled filaments are molded into an elliptical
pattern while maintaining a flexible design. The thickness of the
material is about 0.4 inches. The blanket 12 should be supplied in
minimum two hundred foot lengths or such length as necessary to
allow the blanket widths to be installed across the full width of
the playing field, from one side to the other, in the direction of
slope, with no seams or breaks to inhibit the flow of water. The
widths of the drainage blankets 12 are then bonded together by any
suitable means, preferably using a weather-proof cold adhesive, by
heat-welding, or with a hot-melt adhesive.
[0010] Preferably the blanket 12 is sandwiched between two
permeable geosynthetic or non-woven materials, which allows some of
the rainfall to percolate into the sub-soil. The commercially
available Enkadrain.RTM. material includes the geotextile fabric
sandwich layers. The sandwiching layers are preferably made of a
needle punched polypropylene, and are permeable to water. Each
layer is about {fraction (1/16)}" thick and surrounds a core that
is about 0.4" thick, although these dimensions are not critical.
Other commercially available products include HYDRAWAY WD-100
manufactured by Monsanto. This product incorporates a rigid
interior core composed of round plastic studs sandwiched between
two permeable geosynthetic fabrics.
[0011] The drainage blanket 12 should be used in the widest widths
possible to reduce the number of seams. It is attached to the top
perimeter anchor installed for the synthetic grass and is extended
beyond, into an abutting or near-by trench drain 30 with a direct
or an indirect connection through the drainage stone 32 to an
outflow pipe 35. More specifically, a trench is formed at the edge
of the field and filled with concrete 14. Although FIG. 1 shows
formed concrete, the particular configuration of the trench need
not be so formed, as long as sufficient concrete is poured to
properly function as an anchor. A length of material, preferably
pressure treated (P.T.) wood, is coupled to the concrete by any
suitable means, such as by nailing. The drainage blanket 12 is then
secured to the pressure treated wood, and extends beyond the same.
A second, preferably deeper trench is formed at or near the
concrete anchor, and a perforated drainage outflow pipe 35 is
positioned in the trench. Preferably the perforations in pipe 35
are at or near the bottom of the pipe as the pipe lies in the
trench. The drainage blanket 12 is positioned in the trench to
direct the flow of water towards the pipe 35. The drainage blanket
12 can be in direct communication with the pipe 35, but this is not
absolutely necessary. The trench is then filled with drainage stone
32 or the like to allow water to permeate towards the drainage pipe
35. Water accumulating in the drainage pipe 35 flows out of the
(sloped) pipe and into a further drainage facility as is
conventional in the art.
[0012] One embodiment of the playing surface 1 includes a pile
fabric 9 of individual tufted yarn or yarn-like filaments. The
material used for the yarn filaments is not particularly limited,
and can include polypropylene or polyethylene, or a
polyethylene/polypropylene blend yarn, or other suitable yarn
material. A 100% polyethylene yarn is preferred due to its low
abrasiveness and its grass-like appearance. Tufting through the
backing at a yarn density of about 10 to 60 oz/yd.sup.2, preferably
about 35-45 oz/yd.sup.2, so that the yarn is upstanding and
substantially uniform in height, can be carried out to provide a
higher weight playing surface.
[0013] Conventional artificial turfs have used partially non-woven
backings. However, the characteristics of the non-woven layer are
such that in the tufting and coating process, the non-woven layer
tends to stretch as it is being pulled by the rollers and/or tenner
chain. While the material usually returns to its original
dimensions, this distortion during the manufacturing process
renders the process more difficult and costly to control. In
addition, the physical structure of the non-woven material makes it
difficult to penetrate with sewing needles, both during the tufting
process and also during the seaming process at the job site
installation. This difficulty in penetrating the non-woven material
also limits the weight of the non-woven material that may be used,
which in turn limits the functional ability of the non-woven layer
to impart the desired dimensional stability and weight to the
primary backing of the artificial turf.
[0014] In accordance with one embodiment of the present invention,
this problem is overcome by using a three-layer sandwich
construction for the backing that incorporates only woven fabrics.
The outside layers of the sandwich are a woven polyolefin with a
scarified or fibrillated ("fuzzy") side, commonly referred to in
the industry as "FLW". The fibrillated side is oriented to the
outside of both of the outside layers. The interior layer of the
sandwich is an open weave, isotropic, polymeric material with
excellent dimensional stability (less than 0.2% in any direction),
as manufactured by Amaco Fabrics and Fibers Co. Having the
dimensional stable layer sandwiched bewteen equal fabric layers,
with identical coefficients of expansion, balances the stresses
produced between the stable and unstable layers, eliminating the
tendency for the backing to bend during temperature change as it
does when the stabilizing layer is asymmetrically situated.
[0015] It is also important to orient the scarifed, fibrillated
side of the outside layers (FLW) to the outside of the sandwich,
i.e., so that the fuzzy sides oppose one another. By constructing
the sandwich so that both sides expose the "fuzzy" material is a
significant aid in the field installation of the synthetic turf.
The fibrillated surfaces provide a superior substrate for the
application and bonding of adhesives used in the seaming process,
especially in the incorporation of permanent "inlaid" lines and
markings. The extended fibers provide much greater bonding surface
area and minimize or prevent the adhesives from leaking through the
backing material. Because the fibrillated fabric is on both sides
of the backing, the adhesive can bond one fibrillated side to
another in the installation process. This produces a bond strength
that is more than twice that attainable with prior backing
constructions.
[0016] The top-coating or infill layer 6 is preferably devoid of
sand and its concomitant abrasiveness. It is preferably composed
entirely of resilient material, preferably rubber, including
natural rubber, synthetic rubber such as styrene butadiene (ground
tire rubber), butyl rubber, neoprene, urethane rubber, nitrile
rubber, etc. Preferably a blend of ground tire rubber and high
density rubber is used, with the preferred amount of high density
rubber being about 0-25% of the mix. The incorporation of round,
coated, hydrophobic non-resilient particles, constituting about 2
to 5% by weight of the total infill mix, also can benefit the turf
in several ways. They can reduce the resilience of the infill to a
small degree but enough to "deaden" the feel of the turf. This
produces a feel under the foot that is more like natural grass and
less "spongy". The feel can be specifically adjusted for individual
taste by varying the non-resilient component. In addition, the
incorporation of these particles inhibits the development of static
electricity in the infill matrix, which is a common problem with a
100% ground rubber infill. Because these particles are round,
coated and hydrophobic, they cannot compact (like sand) and
therefore do not inhibit water drainage or reduce the G-max
performance of the system over time.
[0017] The depth of the infill should be substantially uniform and
between about 0.5 inches and 1.75 inches, and is preferably about
1.25 inches in the case where the pile height is 2". Typically the
infill should be between 3/4" and 1" below the full pile
height.
[0018] Other conventional infills, including sand and a combination
of sand and resilient material, also can be used.
[0019] To install synthetic turf in accordance with the present
invention, the vegetative layer (grass and loam), if any, is
removed, and the existing base materials are contoured, graded and
compacted. A minimum 0.5% gradient on the sub-base materials is
necessary, with a slope up to 2% being acceptable. Once the
sub-base materials are fine graded, the dynamic drainage blanket is
placed over the entire area. Preferably the dynamic drainage
blanket is placed in the widest widths possible (most preferably
widths of at least six feet) to reduce the number of seams. The
widths of drainage blanket are then bonded together with an
adhesive, such as a weather-proof cold adhesive, by heat-welding or
with a hot-melt adhesive. The dynamic drainage blanket extends
beyond the playing field to overlap an abutting trench filled with
drainage stone leading to an outflow pipe or conduit. It is secured
to the top of a perimeter anchor installed for the synthetic grass.
Where natural or exiting drainage conditions and contours allow,
the dynamic drainage blanket may be allowed to outflow freely onto
adjacent ground.
[0020] The infilled vertically draining synthetic grass is then
placed over the blanket and installed in its usual manner. The
dynamic drainage blanket has the substantial advantage of enhancing
the system with additional shock attenuation, thus reducing G-max
readings, while not affecting the natural feel of the turf.
Expensive dynamic bases ("E-layers") are not necessary to enhance
G-max.
[0021] The particular Enkadrain product chosen is preferred because
it maximizes the G-max capabilities of the surface without
significantly changing the natural "feel" and playability of the
surface.
[0022] There are three different methods that have been used to
incorporate game lines into an infilled artificial turf surface.
The first involves actually tufting the line directly in the
surface using a different color yarn during the manufacturing
(tufting) process. A second method involves installation of the
lines by cutting and removing the turf from the area that the line
will occupy and then inserting the line material and bonding it to
the abutting turf. The third method is to simply paint the lines.
The present invention utilizes a new method for in situ
installation of game lines. Common line material consists simply of
the same backing material as used for the turf proper, tufted with
the same yarn color as the desired line, where this roll of turf is
then cut into strips of line material of the desired width. In
accordance with the present invention, the backing of the turf is
tufted in specific width lines (usually four inches) with intervals
of untufted backing (usually a minimum of 12 inches between the
lines. After the roll is tufted and coated, it is then cut in the
untufted portion midway between each sewn line segment. This yields
line material with a tufted line having a left and right untufted
flange of at backing material, with each flange having a width of
at least 6 inches each. Adhesive is then applied to the top of the
flange of the line material and the bottom of the abutting turf of
the playing field, and the flanges are inserted under the abutting
turf. The tuft and line are then pressed together by application of
weight such as with a roller. Less time and less adhesive are
required than with conventional methods, and the level of skill and
precision necessary to successfully carry out the seaming process
is reduced. Preferably the line material backing is an FLW backing
layer with the fleeced side facing up, which results in more
surface area for bonding to the turf.
* * * * *