Note: Descriptions are shown in the official language in which they were submitted.
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BACKGROUND OF THE INVENTION
Field of the Invention
The present invention concerns the game of golf, in general,
and more particularly a synthetic turf having a simulated
grass surface; a method of treating it; border strips for
artificial minigolf, and an understructure for an artificial
large size golf course.
Description of the Prior Art
Synthetic turfs are well knowq in the prior a~t, for example
~in U.S. patents Nos.~ ~ ~56,'22~; 4,38~4~5 /and~4,497,853.
They generally include a fabric base tufted with
conventional artificial grass blades held to the fabric base
by an adhesive material such as polyurethane which also
provides a certain cushioning effect.
Also known in the prior art, more particularly in U.S.
patent 3,735,988, i9 a practice putting surface making use
of vertical border strips intended to prevent the golf ball
from rolling off the putting surface.
~ Further~patents found in a prior art search are as follows:
3,~57;3,147; 3,577,681 3,597,297; 3,740,303; 3,801,421;
3,995,~079; 4,061,804; 4,902,540; and 4,902,541.
One drawback with the above-mentioned patents is that these
artificial turfs do not provide a very good imitation of
notural turf.
Also, none of the above-mentioned patents provides an
adequate strip border for minigolf.
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According to one aspect of the present invention, it is an
object to propose an artificial turf providing a better
imitation of a natural turf than the one known in the art.
According to another aspect of the present invention, it is
an object to provide a strip border for minigolf that
present interesting characteristics for golf players.
According to another aspect of the present invention, it is
an object to provide an understructure for a large size golf
surface, allowing modifications of the shape of the golf
surface.
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SUMMARY OF THE INVENTION
According to the present invention, there is provided a
synthetic turf comprising:
- a base made of fabric material;
- a mass of entangled, crimped grass-like frayed blades
made of a material selected from the group consisting of
polypropylene, nylon and polyester; said blades being
grouped into tufts projecting upwardly from said base; and
- a layer of adhesive material fixing lower ends of said
tufts into said base, said blades have a length in the range
of 3/8'! to 2" and a weight in the range of 28 to 60 ounces
per square foot.
Thus, a dense and uniform playing surface is obtained to
allow a golf ball to hold on to its trajectory after being
hit, much as on a natural golf course. The synthetic grass
material, previously tinted green, also loses its luster
during sandblasting and adapts a pale green close to that of
natural grass.
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According to the present invention, there is also provided a
method of treating a grass-like blade surface of a synthetic
turf, said method comprising steps of:
- selecting a synthetic turf including blades made of a
material chosen in the group consisting of polypropylene,
nylon and polyester; said blades being grouped into tufts
projecting upwardly from a fabric base; and
- sandblasting said blades from above said turf at a
distance of about 3 to 4 feet with a jet of sand having a
pressure of about 80 to 120 pounds per square inch directed
at an angle of about 70 to 80 from the horizontal and in a
circular motion.
According to the present invention, there is also provided a
border strip for an artificial golf practice course, this
border strip can be mounted to extend along edges of a
playing surface, said border strip comprising a body made of
polystyrene of type 2, a sheet of polypropylene laminated
over said body, and a synthetic turf covering fixed over
said sheet of polypropylene, said body being shaped so that
said synthetic turf covering forms a ball rolling surface
inclined or square with respect to said playing surface.
Known in the art are vertical border strips intended to
prevent a golf ball from rolling off the putting surface.
These strips are made of hard material and have the effect,
however, of producing big rebound of the ball. To eliminate
this drawback, a border strip as described above is
provided.
According to the present invention, there is also provided
an understructure for an artificial game surface,
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comprising:
- a plurality of platform structures arranged side-by-
side, said platform structures establishing nodal points at
junctions of every group of four adjacent platform
structures:
- a plurality of lifting jacks, each of said jacks being
disposed at one of said nodal points; and
- a plurality of connecting means, each of said means
connecting corners of the adjacent platform structures at
one of said nodal points to the relevant one of said jacks,
whereby said golf surface has a shape that can be modified
by means of said lifting jack.
A description now follows of preferred embodiments of the
invention having reference to the appended drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic elevation view of a portion of a
synthetic turf surface being subjected to a sandblasting
treatment;
Figure 2 is a top plan view of a portion of a golf practice
course;
Figure 3 is a cross-section along line III-III of Figure 2,
showing a border strip according to the present invention;
Figure 4 is a top plan view of a portion of an
understructure for an artificial golf course;
Figure 5 is a top plan view, on an enlarged scale, taken at
a nodal point in the plan view of Figure 4;
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Figure 6 is a cross-sectional view taken along line VI-VI in
Figure 4;
Figure 7 is a top plan view of a portion of the wooden
understructure supporting the lifting jacks;
Figure 8 is a side elevation view, partly brokeh away to
show the inner construction, of the lifting assembly and
platform structure, the view being taken at a nodal point of
the golf course understructure;
Figure 9 is a top plan view of a lifting jack plate; and
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Figures 10 and 11 are plan views of anchor plates located at
the corners of a surface panel of one platform structure of
the understructure.
DESCRIPTION OF THE PREFERRED EM~O IMENTS
Referring to Figure 1, there is shown a synthetic turf 1. It
consists of a base 3 made of a fabric material and from
whLch vertically emerge grass-like blades 5 grouped into
tufts fixed by their lower ends solidly to the base by a
layer of adhesive material. The latter may be polyurethane
or its equivalent~ The blades 5 are made of a material
selected from the group consisting of polypropylene, nylon
and polyester. Also, their length lies in the range from
3/8" and 2n, their weight in the range from 28 to 60 ounces
per~square foot while their denier value is about 5400. The
synthetic turf according to the present invention is shown
in 6,~the~blades of the grass-like turf are frayed by means
of a sandblast process.
Where the turf is to be used on an artificial golf green,
their length is from 3/8" to 3/4" and their weight from 60
to 40 ounces per square foot, respectively. If they are to
be used on a teeing surface, they have a length of about 2 H
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while their weight is of about 28 ounces per square foot.
Also, a second synthetic turf can be juxtaposed to the turf
mentioned above, used for artificial golf green. This second
turf comprises a base made of fabric material, a mass of
entangled crimped grass-like blades made of a material
selected from the group consisting of polypropylene, nylon
and polyester. The blades are grouped into tufts projecting
upwardly from the base. A layer of adhesive material fixes
lower ends of the tufts into the base. The blades have a
length in the range of 3/4" and 1", a weight of about 38
ounces per square foot and a denier value of about 5400.
According to the invention, the surfaces of the blades are
treated by sandbIasting from a sand source in the form of a
hose 7 provided at its end with a nozzle 9. The source must
be capable of giving a sand pressure of 80 to 120 pounds per
square inch. The sand itself should have a screen mesh
particle size in the range from 16 to 40. It preferably is a
~brown or alvine sand having a screen mesh particle size of 24.
In the practice of the method, a person places the nozzle 9
by hand at a distance of about 3 to 4 feet above the turf 1
and the jet 11 is directed against the blades 5 at an angle
of about 70 to 80 from the horizontal. The jet is applied
by~ the pe~rson with a circular motion, in a direction
contrary to that of the blades. Of course, the nozzle can be
moved by a machine.
As ~aid above, the method of the invention makes it possible
to obtain a turf surface wherein the blades become
entangled,~ crimped and frayed so as to hide the base 3
of fabric material properly and completely, resulting in a
dense and uniform playing surface capable of holding a
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running ball on its trajectory, after being hit, very much
as on a natural golf course. The blades also lose their
luster and become pale green close to that of natural grass.
Figures 2 and 3 show another aspect of the inventian in the
form of an artificial golf practice course 13 having a
horizontal planar central playing surface 15 along either
edge of which extend the border strips 17 defining, on their
faces looking toward the central playing surface, ball
rolling surfaces 19 that are inclined at an angle preferably
ranging from 30 to 40, or square. The border strip 17
comprises a body 14 made of polystyrene of type 2, a sheet
16 of polypropylene laminated over said body 14 and a
synthetic turf, that can be of the type described above, is
layed over and made fast with both the playing surface 15
and the rolling surfaces 19. The sheet of polypropylene has
a thickness of 1/2 inch to 1 inch and a density of 2 to 6
pounds per square foot. The grass-like blades have a height
preferably of 3/4" to 1" and a weight of 28 ounces per
square foot. As to the border strips, their height can be
about 8". The inclination of the rolling surface makes it
possible to hold the golf ball more accurately on the golf
after having been hit by the golf player.
Figure 4, illustrating only a portion 21 of an
understructure for an artificial large size golf course made
according to the invention, shows a group of 9 rectangular
platform structures 23 of, for example, 8' x 8'. Please note
that the platforms are not necessarily rectangular. They can
be triangular, for example. These structures are arranged
side-by-side in the form of a checker-board establishing
nodal points 25 at the junctions of every group of four
adjoining panel structures. A lifting jack 27, shown in
Figures 6 and 8, is provided at each nodal point. The
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corners of adjacent platform structures 23 being connected
to the relevant lifting jack~
Each platform structure 23 comprises a rectangular sub-frame
made up of longitudinal channel-shaped side members 29
joining, at their ends, with the ends of transverse channel-
shaped side members 31 and the manner shown in Figure 8. The
sub-frame should also include central transverse
strengthening channel-shaped beams 34 interconnecting the
side members 29, and 31.
As illustrated in Figure 8, the web 33 of one side member 31
is bent inward, at its end, for use as a connecting flange
35 fixed, by self-tapping screws for instance (not shown) to
the web 37 of the crossing side member 29. The same applies
at each corner connection of two meeting members 29 and 31.
The ends of the upper flanges 39 of the side members 31 are
cut off at 41 to allow for the insertion of the members 31
into the members 29 and thus allow the flanges 39 to be made
level with the upper flanges 43 of the side members 29.
Secured to the side members 29 and 31 at their junctions, as
by self-tapping screws (not shown), are L-shaped bottom
corner anchor plates 45 shown in Figure 11 and top corner
anchor plates 47 shown in Figure 10. It will be noted from
Figures 10 and 11, that the plates 45 and 47 are cut out of
rectangular plates of equal size, therefore having side
edges of equal length overlapping one another in the
situation of Figure 8. Also, the combined plates 45 and 47
largely overlap the frame members 29 and 31.
Finally, each platform structure 23 further comprises a
plywood floor panel 49, which can be made of any other
flexible material such as fiber glass, fixed to the anchor
plates 45 and 47, as well as to the upper flanges 39 and 43,
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of the frame members 31 and 29, by any known means such as
by self-tapping screws. In this manner, it will be
understood that the sub-frames 29 and 31, the anchor plates
45 and 47, and the plywood floor panel 49 form a solid body.
It should be noted that the side edges of the floor panel
fall in line with the corresponding side edges of the plates
45 and 47, as best seen in Figure 8.
In this Figure 8, it is seen that each lifting jack 27 is
made up of a lifting rod in the form of a hollow cylindrical
pipe 51 having, fixed transversely at its upper end, a
rectangular jack plate 53, also shown in Figures 5 and 9.
Every platform structure 23, around a nodal point 25, is
secured to the corresponding jack plate 53, at one corner by
a single bolt and nut combination 55 of which the bolt
extends successively through an appropriate hole 57 of the
floor panels 49, hole 59 of the anchor plate 47, hole 61 of
the second anchor plate 45, and finally hole 63 in the jack
plate 53, as shown in Figures 9, lO and 11.
Referring now to Figure 8, it is seen that the floor panels
49 and the anchor plates 45 and 47, overhang the side
members 29 and 31 sufficiently to allow them to avoid the
jack plate 53.
As shown, the anchor plate 45 is formed with a through
torsion slot 65 between each two successive bolt holes 63,
in alignment two-by-two and opening on an edge of the plate.
Each jack 27 further comprises a power screw 67 of which the
upper end is slid into the relevant jack pipe 51 while its
lower end is secured to a wooden supporting understructure
66 shown in Figure 7. The latter is formed of a series of
parallel longitudinal T-shaped beams 69 interconnected by
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cross-beams 71. Each beam 69 has a top rectangular element
73 lying flat on an edgewise rectangular vertical element 75
to which it is nailed. The jack seating plate 77 is fixed,
as by screws, to the top element 73. Finally, adjustment of
S the height of the jack pipe 51 is obtained by power nut 79.
A lock nut 81 serves to hold the jack 27 at a selected
height. As to the wooden understructure 67, it is made to
rest on level ground 83 which is preferably obtained with
compacted sand.
As shown in Figure 8, the top face of each floor panel 49 is
covered with a turf carpet 85, which may be of the type
described above, glued to a cushioning underlayer 87 of
polypropylene, itself secured to the floor panel 49. A
narrow polypropylene strip 89 is made to fill the space
between two adjacent underlayers 87.
Once the wooden understructure 67 has been set firm and
level on the ground 83, the jacks 27 are fixed to it and
operated to lift the platform structures 23 at different
preselected heights for them to define an undulated golf
course forming mounds and depressions. The use of a single
bolt connection 55 joining one corner of a platform
structure 23 to a corner of a jack plate 53, along with the
provision of the slots 65 through the same plate are
intended to relieve the pressure created by the lifting
jacks 27 for providing the different nodal heights.
Although the present invention has been explained
hereinabove by way of a preferred embodiment thereof, it
should be pointed out that any modifications to this
preferred embodiment, within the scope of the appended
claims is not deemed to change or alter the nature and scope
of the present invention.
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