Note: Descriptions are shown in the official language in which they were submitted.
1338810
-1- 22-21(1265)
ARTIFICIAL TURF SYSTEMS
Background of the Invention
This invention relates to an artificial
turf playing field comprising a layer of artificial
turf overlying a supporting cushion comprising an
underlaying layer of artificial turf. This invention
also relates to a method and apparatus for
manipulating large sections of artificial turf over a
previously installed field of artificial turf
utilizing a pneumatic cushion.
In multi-use stadiums artificial turf fields
for different athletic contests are arranged with
different shaped fields having distinctive markings on
the playing surface. Such fields include American
football fields, association football fields, and
baseball fields. Considerable time and expense are
required to convert artificial turf surfaces from one
field configuration to another to accommodate different
athletic events.
In some cases the same artificial turf is
utilized for different athletic events. This often
requires that line markings must be removed prior to
new line markings painted on the artificial turf
surface to accom~odate different athletic events.
Moreover, when a field is converted from use as a
baseball playing surface to a football playing surface
individual segments of artificial turf are
generally required to cover dirt surfaces, for
instance at the location of a baseball infield.
In other cases part or all of the
artificial turf for one athletic contest is removed
and different sections of artificial turf are laid
down to provide a playing surface for different
athletic events. Such a procedure generally requires
considerable effort as artificial turf surfaces are
recovered and laid out from large rolls of artificial
*
1338810
- -2- 22-21(1265)
turf. Considerable effort is also required to fasten
and unfasten individual rolls of artificial turf
comprising a unified field. This procedure can be
simplified somewhat using the method and apparatus
for manipulating large sections of artificial turf by
means of a pneumatic cushion as disclosed, for
instance in U.S. Patent 4,39g,954.
In still other cases only a portion of an
athletic field is modified to accommodate different
athletic events. For instance to convert a baseball
playing field of artificial turf to a football
playing field of artificial turf it is known to
provide an overlying section of artificial turf over
a baseball infield. The overlying section of
artificial turf comprises a composite of artificial
turf and polymeric foam support pad which provides a
difference in elevation from one portion of the
football playing field to the other portion of the
football playing ield. As illustrated in Figure 2
attempts have been made to provide a somewhat smooth
transition by providing the edge of the overlying
section (20) with a transition piece of tapered
polymeric foam (21). Such installations are generally
undesirable because of a lateral seam across the field
at the transition can provide a tripping hazard. A
further undesirable feature results from the extreme
thickness of the multiple layers of artificial turf at
that section of the field having the overlying section.
There is footing instability and a marked sensation of
3Q softness on that position of the field having an
overlying section of composite artificial turf with a
foam support cushion as compared that portion of the
field having a single layer of artificial turf.
By this invention applicant has attempted
to provide an artificial turf system which provides
`
_ _ 3 _ 1338810
the advantages of rapid field conversion without the
attendant disadvantages of the prior art.
SUMMARY OF THE INVENTION
By this invention applicant has provided an
artificial turf playing field comprising a layer of
artificial turf overlying a supporting cushion
comprising an underlying layer of artificial turf.
In accordance with an embodiment of the present
invention there is provided an artificial turf playing
field comprising a layer of artificial turf overlying
a supporting cushion comprising an underlying layer of
artificial turf having ribbons extending generally
vertical from a backing.
In accordance with another embodiment of the
present invention there is provided an artificial turf
playing field comprising a layer of artificial turf
overlying a supporting cushion of an underlying layer
of artificial turf laminated to a polymeric foam pad,
the underlying layer of artificial turf having ribbons
extending generally vertical from a backing.
In accordance with a further embodiment of the
present invention there is provided a method of
installing an artificial turf playing field comprising
a layer of artificial turf over a supporting cushion
comprising an underlying layer of artificial turf, the
method comprising providing a pneumatic cushion to
facilitate manipulation of the overlying layer of
artificial turf.
In accordance with still another embodiment of
the present invention there is provided a method for
removably covering a field of artificial turf with an
overlying section of impervious artificial turf which
comprises (a) dragging the leading margin from a roll
of the overlying section across an initial portion of
a field of artificial turf, wherein the roll is
supported on at least one powered support roller;
D
~- - 3a - 1338810
(b) turning the roll comprising the remainder of the
overlying section in place in an unwinding direction
while continuing the application of a pulling force to
further advance the section across the field; (c)
generating pneumatic pressure between the field and
the overlying section to lift the overlying section
within its margin off the field and to minimize
friction between the field and the overlying section;
(d) continuing to apply a pulling force until the
field is covered with the overlying section; and (e)
then relieving the pneumatic pressure to permit the
overlying section to settle onto the field.
Brief Description of the Drawings
Figure 1 schematically illustrates a cross-
sectional view of a portion of an artificial turf
playing field comprising a layer of artificial turf
overlying a support cushion comprising an underlying
layer of artificial turf.
Figure 2 schematically illustrates the prior art
practice of utilizing an overlying layer of artificial
turf adhered to a support cushion with
D
1338810
-4- 22-21(1265)
a tapered segment to provide a transition between the
different elevations of artificial turf.
Figures 3 and 4 schematically illustrate the
usefulness of an overlying layer of artificial turf
over an underlying layer of artificial turf in a
multi-use stadium.
Detailed Description of Preferred Embodiments
This invention provides an artificial turf
playing field comprising a layer of artificial turf
overlying a supporting cushion comprising an
underlying layer of artificial turf. Figure 1 shows
an overlying layer of artificial turf (1) comprising
pile (2) in the form of ribbons of synthetic
thermoplastic material such as nylon, polypropylene
or the like, knitted, tufted or woven or otherwise
secured to a backing (3). This playing surface of
artificial turf overlies a support cushion comprising
an underlying layer of artificial turf (4) which
comprises pile (5) in the form of ribbons of
synthetic thermoplastic material secured to a backing
(6) to which an underlayer in the form of a resilient
pad (7) comprising a foam structure is laminated,
such as by means of a suitable adhesive, or generated
by foaming in place.
Since the overlying layer of artificial
turf is not adhered to a rigid surface means must be
provided to insure dimensional stability of such
overlying layer. Dimensional stability can be
provided by a variety of means, for instance by
applying a coating of polymeric material such as
polyurethane to the underside of the backing (3).
This provides resistance to stretching and wrinkles
that otherwise may develop in the overlying layer of
artificial turf. Moreover, since the overlying layer
of artificial turf must generally be secured by pins
or tensioning members at its periphery, dimensional
- 1338810
-5- 22-21(1265)
stability insures that line markings will have the
same dimensional accuracy each time the overlying
layer of artificial turf is deployed for use.
If the underlying layer of artificial turf
comprises grass-like ribbons extending from a backing
at a pile angle of, for instance, 80 or less from
horizontal, the overlying layer of artificial turf
will tend to walk or creep in the direction of the
pile lay. This could cause disruptions in field
dimensions, wrinkles in the overlying section, or
of lateral movement of the overlying section. It
has been discovered that such problems can be avoided
by utilizing an underlying layer of artificial turf
comprising grass-like ribbons extending generally
vertically from the backing at a pile angle of
about 90 from horizontal. The maintenance of
grass-like ribbons at such pile angle is best
achieved by utilizing crimped, grass-like ribbons at
a high pile density.
A preferred underlying layer of artificial
turf will comprise grass-like ribbons having a ribbon
denier in the range of 300 to 670, a pile height
of 0.38 to 0.50 inches (9.7 to 12.7 millimeters), a
pile density of 600 to 1200 ribbons per square inch
(93 to 186 ribbons per square centimeter~. Such
preferred underlying layer of artificial turf will
provide a stable support for an overlying layer of
artificial turf. Because of the generally 90 pile
angle the blades of the underlying artificial turf
will not compress by laying over but will stand
generally erect even under compression. Accordingly,
a firm footing is provided.
Another aspect of this invention provides a
process for manipulating the large sections of
impermeable artificial turf over an artificial turf
surface on a pneumatic cushion. The manipulation of
~- G - 1338810
large sections of artificial turf over a smooth rigid surface
such as a floor while supported on a pneumatic cushion to
minimize frictional drag is disclosed in U.S. Patent
4,399,954. The present invention provides a significant
improvement obviating the requirement for a smooth rigid
surface. In this regard this invention provides for the
manipulating of a large section or artificial turf on a
pneumatic cushion between an overlying layer of said large
section of artificial turf and a fixed support layer of
artificial turf.
This invention is useful in converting artificial
turf playing fields in multi-use stadiums.
In this regard Figure 3 illustrates a generally
circular shaped stadium (32) having an artificial turf
playing field (34) in a configuration suitable for playing
baseball. Within the stadium are seating segments (36) which
can move in an arcuate direction within the circular
circumference of the stadium generally on arcuate tracks.
When the seating segments are moved to provide a generally
rectangular playing field, for instance for football, the
seating segments are required to move over a portion of the
artificial turf utilized for the baseball playing field. The
seating segments can conveniently be moved on the arcuate
tracks, a portion of which extend into the outfield portion
of the baseball playing field. These tracks can be located
in trenches at locations (38) which are provided with
removable covers having an upper surface of artificial turf
to provide a smooth playing field.
Figure 4 illustrates a stadium with seating
segments rotated into a position to provide for the
installation of a generally rectangular playing field (40).
Playing field (40) in accordance with this
- 3~8810
-7- 22-21(1265)
invention comprises an overlying layer of artificial
turf installed over an underlying layer of artificial
turf (34). The overlying layer of artificial turf is
conveniently stored on a roll in elongated pit (42).
To deploy the overlying layer of artificial turf the
leading margin (46) of the overlying layer of artificial
turf is pulled from the roll within the pit until it
extends beyond pressurized air vents (44). A pneumatic
cushion of air is supplied through vents (44~ to
provide a pneumatic cushion between the overlying
layer of artificial turf and the underlying surface.
The overlying layer of artificial turf supported on
the pneumatic cushion can then be fully deployed by
continuing to pull the leading margin of the overlying
layer.
A sufficient length of artificial turf is
provided so that when the field is fully deployed a
portion of the overlying layer of artificial turf
remains attached to a~cylindrical core stored within
the pit (42). This cylindrical core supporting the
roll of artificial turf is conveniently mounted on
support rollers to facilitate rotation of the roll.
Advantageously, at least one of the support rollers
is powered so that the rotation of the roll can be
facilitated.
To recover the overlying layer of
artificial turf a pneumatic cushion is provided by
blowers directing air under the overlying layer
through ports (44). When the overlying layer is
separated from the underlying support by a pneumatic
cushion, the powered support rollers can be driven to
rewind and recover the overlying layer of artificial
turf in a roll wound on the elongated core.
Optionally the playing field can be installed
with the pit (42) and pors (44) located in the baseball
outfield.
-` 1338811~ -8- 22-21(1265)
The foregoing description of embodiments of
this invention is not intended to be a limitation to
the scope of this invention. As will be apparent to
those skilled in the art, many variations and
modifications can be made to the playing field and
apparatus of this invention as described in the above
embodiments without departing from the spirit and
scope of this invention.
