U.S. patent application number 12/026866 was filed with the patent office on 2008-05-29 for artificial turf with granule retaining fibers.
This patent application is currently assigned to Textile Management Associates, Inc.. Invention is credited to George S. Avery.
Application Number | 20080124496 12/026866 |
Document ID | / |
Family ID | 39464034 |
Filed Date | 2008-05-29 |
United States Patent
Application |
20080124496 |
Kind Code |
A1 |
Avery; George S. |
May 29, 2008 |
ARTIFICIAL TURF WITH GRANULE RETAINING FIBERS
Abstract
An artificial turf is provided that resists migration of rubber
infill into the space above the turf. Artificial grass is attached
to and extends upward from a backing material, which may be one or
more layers. The artificial grass includes groups of at least two
different kinds of fiber sewn through a common path in the backing
material. One of the kinds of fibers is an artificial grass blade
shaped so as to appear like a blade of grass. The other kind of
fiber in each group is pre-stressed/crimped so that the relaxed
shape of the fiber is nonlinear, resembling a curlicued or
articulated form having lateral excursions. The lateral excursions
cause portions of one such pre-stressed fiber to overlap and
interfere with another, forming a mesh. The height of the
pre-stressed fibers in their relaxed state in the turf is less than
the height of the relatively unstressed fiber(s). Resilient
granules are embedded in the mesh, and are captivated by the
interfering pre-stressed fibers. In one embodiment, the
pre-stressed fiber is constructed of nylon material, and the
relatively unstressed artificial grass blade of polyethylene.
Inventors: |
Avery; George S.;
(Minneapolis, MN) |
Correspondence
Address: |
JOHN S. PRATT, ESQ;KILPATRICK STOCKTON, LLP
1100 PEACHTREE STREET
ATLANTA
GA
30309
US
|
Assignee: |
Textile Management Associates,
Inc.
Dalton
GA
|
Family ID: |
39464034 |
Appl. No.: |
12/026866 |
Filed: |
February 6, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10733806 |
Dec 10, 2003 |
|
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12026866 |
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Current U.S.
Class: |
428/17 ;
156/72 |
Current CPC
Class: |
A41G 1/009 20130101;
D05C 17/02 20130101 |
Class at
Publication: |
428/17 ;
156/72 |
International
Class: |
A41G 1/00 20060101
A41G001/00; D05C 15/00 20060101 D05C015/00 |
Claims
1. An artificial turf comprising: a backing; and a plurality of
resilient first fibers pre-stressed so as to have a non-linear
shape with lateral excursions when not under tension, and a
plurality of second fibers shaped to resemble grass blades, wherein
at least one first and at least one second fiber are sewn through
common openings in said backing, and extend upward from said
backing to a cut end.
2. A turf as recited in claim 1 wherein said first fibers extend
upward from said backing a first height and said second fibers
extend upward from said backing a second height greater than said
first height.
3. A turf as recited in claim 2 further comprising particles
including resilient granules positioned in said turf.
4. A turf as recited in claim 2 wherein said second height is in
the range of 2 to 3 inches, and said first height is in the range
of 13/4 to 23/4 inches.
5. A turf as recited in claim 3 wherein a layer of said granules
extends upward from said backing a height less than said first
height.
6. A turf as recited in claim 5 wherein said lateral excursions of
said first fiber provide resistance to motion of said
particles.
7. A turf as recited in claim 6 wherein groups of said first fibers
are spaced apart such that lateral excursions of first fibers of
one group overlap lateral excursions of first fibers of an adjacent
group thereby providing a mesh for resisting movement of said
particles.
8. A turf as recited in claim 7 wherein said groups of first fibers
are in rows separated by distances in the range of 3/8'' to
3/4''.
9. A turf as recited in claim 1 wherein said first fibers are made
from nylon.
10. A turf as recited in claim 1 wherein said second fibers are
made from polyethylene.
11. A method of manufacture of artificial turf comprising: sewing
into a backing a plurality of resilient first fibers pre-stressed
so as to have a non-linear shape with lateral excursions when not
under tension, and a plurality of second fibers shaped to resemble
grass blades, wherein at least one first and at least one second
fiber are sewn through common openings in said backing, and extend
upward from said backing to a cut end.
12. A method as recited in claim 11 wherein said first fibers
extend upward from said backing a first height and said second
fibers extend upward from said backing a second height greater than
said first height.
13. A method as recited in claim 12 further comprising inserting
particles including resilient granules in said turf.
14. A method as recited in claim 12 wherein said second height is
in the range of 2 to 3 inches, and said first height is in the
range of 13/4 to 23/4 inches.
15. A method as recited in claim 13 wherein a layer of said
granules extends upward from said backing a height less than said
first height.
16. A method as recited in claim 15 wherein said lateral excursions
of said first fiber provide resistance to motion of said
particles.
17. A method as recited in claim 16 wherein groups of said first
fibers are spaced apart such that lateral excursions of first
fibers of one group overlap lateral excursions of first fibers of
an adjacent group thereby providing a mesh for resisting movement
of said particles.
18. A method as recited in claim 17 wherein said groups of first
fibers are in rows separated by distances in the range of 3/8'' to
3/4''.
19. A method as recited in claim 11 wherein said first fiber is
made from nylon.
20. A method as recited in claim 11 wherein said second fiber is
made from polyethylene.
Description
FIELD OF THE INVENTION
[0001] The present invention relates generally to artificial turf,
and more particularly to an artificial turf including a plurality
of groups, of fibers, each group including both straight and
non-linear fibers sewn into a backing through a common opening,
with the non-linear fibers providing captivation of granular
infill.
DESCRIPTION OF THE PRIOR ART
[0002] Artificial turf is used in a variety of areas, such as on
athlete playing fields for football, soccer, baseball, tennis, etc.
The artificial turf is usually made to simulate a natural grass
field. U.S. Pat. No. 5,601,886 by Ishikawa et al. describes an
artificial turf consisting of alternate rows of longer and shorter
artificial grass filaments sewn into a backing. A layer of sand is
deposited into the artificial turf so as to cover the shorter
filaments. A disadvantage of this structure is that the sand infill
tends to compact and harden, and has an abrasive quality.
[0003] U.S. Pat. No. 4,396,653 by Tomarin discloses sewing pile
fibers into a backing, and then depositing a bottom layer of
rubber-like particles, and then a binder for gluing some of the
particles together. A second layer of sand is then deposited over
the first layer wherein the depth of the first and second layers is
less than the height of the pile fiber.
[0004] U.S. Pat. No. 6,527,889 by Paschal et al describes a
structure that appears similar in purpose to that of Tomarin's,
wherein the rubber particles of a first bottom layer are coated
with a bonding agent. Application of water to the layer then
activates the bonding agent for adhering the particles together. A
second, top layer of rubber particles is then deposited over the
bottom layer.
[0005] U.S. Pat. No. 6,299,959 by Squires et al. discloses a
grass-like surface formed with polyethylene co-polymer slit fibers
tufted through a fiberglass reinforced backing. Three layers of
infill are then deposited. The bottom layer is rubber granules, and
the top two layers are each a mixture of rubber and sand.
[0006] The above described patents using rubber granules or rubber
and sand mixtures provide a more resilient, shock absorbent
surface. A disadvantage is that some of the rubber particles become
air-borne upon impact with the turf. For example, football players
impact turf with shoulders and helmets, etc., bringing the player's
faces close or in contact with the turf. The small "rubber
granules" are often created by grinding up used automobile tires,
and include the various components, including natural and synthetic
rubber and ground up steel belt. These finely ground particles can
be ingested by players, and may be a health hazard, or at least a
potential irritant.
SUMMARY
[0007] It is an advantage of this invention in that it provides an
artificial turf having an improved stability.
[0008] It is a further advantage of this invention in that it
provides a combination of good shock absorption with stability of
rubber infill.
[0009] It is a still further advantage of this invention in that it
provides improved retainment of rubber infill in combination with
good shock absorption, and reduces the quantity of infill that
escapes into the air above the turf.
[0010] In one embodiment of this invention, an artificial turf is
provided that resists migration of rubber infill into the space
above the turf. Artificial grass is attached to and extends upward
from a backing material, which may be one or more layers. The
artificial grass includes groups of at least two different kinds of
fiber sewn through a common path in the backing material. One of
the kinds of fibers is an artificial grass blade shaped so as to
appear like a blade of grass. The other kind of fiber in each group
is pre-stressed/crimped so that the relaxed shape of the fiber is
nonlinear, resembling a curlicued or articulated form having
lateral excursions. The lateral excursions cause portions of one
such pre-stressed fiber to overlap and interfere with another,
forming a mesh. The height of the pre-stressed fibers in their
relaxed state in the turf is less than the height of the relatively
unstressed fiber(s). Resilient granules are embedded in the mesh,
and are captivated by the interfering pre-stressed fibers. In one
embodiment, the pre-stressed fiber is constructed of nylon
material, and the relatively unstressed artificial grass blade of
polyethylene.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 illustrates an artificial turf according to the
present invention;
[0012] FIG. 2 illustrates two fibers through one needle, and fiber
tension;
[0013] FIG. 3 is a table of example dimensions of fiber and infill
height;
[0014] FIG. 4A shows one type of artificial grass fiber
construction; and
[0015] FIG. 4B shows the fiber of FIG. 4A rolled up.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] While the present invention will be described herein with
reference to particular embodiments thereof, a latitude of
modifications, various changes and substitutions are intended, and
it will be appreciated that in some instances some features of the
invention will be employed without a corresponding use of other
features without departing from the spirit and scope of the
invention as described with respect to the preferred embodiments
set forth herein.
[0017] Referring now to FIG. 1 of the drawing, the artificial turf
10 of the present invention is illustrated. A backing material 12
has two different kinds of fiber 14 and 16 sewn into it, with both
fiber 14 and 16 passing through the same passages 18 in the backing
12. Fiber 14 is an artificial grass blade that can be constructed
in a number of ways to give the turf a grass like appearance. Fiber
16 is pre-stressed into a non-linear shape, creating a mesh for
retaining infill 24. The tops 20 and 22 of the fibers are cut,
forming a "cut fiber" carpet/artificial turf, resulting in the
fiber 14 appearing grass-like. The fibers 14 are relatively
un-stressed and have only minor deviations from linearity, similar
to a linear/straight grass blade appearance. Fibers 16 are
pre-stressed prior to being sewn into the backing. During the
sewing process, fibers 14 and 16 are both threaded together through
the same sewing machine needle passages, and therefore pass through
the same openings 18 in the backing through which the needle is
inserted. Axial/longitudinal tension on the fibers 14 and 16
provided by the sewing machine keep both fibers 14 and 16 under
tension, and most importantly, fibers 16 are held in an uncrimped,
straight line. Upon being sewn into the backing 12, the tension on
fiber 16 is released and it returns to its pre-stressed/crimped
condition, that could be described as curlicued. The
lateral/horizontal excursions such as excursion "x" of the fibers
16 provide resistance to migration of particles 24 placed in the
artificial turf, which most commonly are ground up used tires, the
resulting granules having a resilient, shock absorbing
characteristic.
[0018] In one embodiment, the fibers 14 are constructed of
polyethylene and fibers 16 of nylon. The polyethylene has a slick
surface which helps avoid injury from, for example a football
player twisting an ankle due to turf resistance/friction. The
dimensions of the stitch spacing S and row spacing R, are selected
along with the design of the pre-stressed shape of the fiber 16, so
that lateral excursions of a fiber 16 from one passage 18 overlap
the excursions of a fiber 16 from an adjacent passage 18. In this
way, an effective mesh of fiber 16 is formed that resists migration
of the rubber particles 24, both upward and horizontally.
[0019] FIG. 2 is provided to illustrate the tension applied to the
fibers 14 and 16 during the process of sewing. The initial ends 26
of the fibers 14 and 16 are secured during the process. The needle
28 is inserted through the backing 12, taking both fibers 14 and 16
through a common passage 18. A hook 30 grabs the loop of fibers and
keeps the fibers from retracting back through the passage 18 as the
needle 28 is retracted. The sewing machinery then inserts the
needle 30 through the backing again at a stitch space "S" (FIG. 1)
from the first space 18 and the hook 30 grabs the material again. A
cutting tool (not shown) follows along or is integrated with the
hook apparatus 30 and cuts the loop ends 32, at which time the
tension on the cut fiber 16 is released and the fiber 16 returns to
its curlicued/non-linear state as shown in FIG. 1.
[0020] In one embodiment, the fibers 14 are constructed of
polyethylene, and extend upward from the backing a distance H1 of
approximately 3 inches. The retracted, rest state curlicued fibers
16 extend upward from the backing a distance H2 of approximately 21
inches. The height H3 of the rubber infill granules 24 in this
particular embodiment is approximately 13/4 inches. This
combination of heights and other examples are listed in FIG. 3.
Other dimensions are also included in the spirit of the present
invention, as will be apparent to those skilled in the art. In
general, the height H2 of the curlicued fiber 16 must be shorter
than the height of the relatively straight fiber 14, and the height
of the infill H3 is less than the height H2 in order to optimize
the captivation of the granules, but can also be somewhat higher,
particularly if a different granule material is used above the
fibers 16 that is less irritating to those who play on the
turf.
[0021] As described above, the straight fiber 14 may be constructed
from polyethylene, which provides a slippery surface similar to
grass. Other materials that simulate the grass-like property of low
resistance/friction are also included in the spirit of the present
invention. The nylon fiber 16 is selected for its resiliency and
ability to hold the granules 24 in the turf. Other materials for
fiber 16 that will retain the granules in a similar way are also
included in the present invention.
[0022] The grass-like fibers 14 can be constructed in a variety of
ways that will be apparent to those skilled in the art for use in
the turf of the present invention, and the present invention
includes the use of these constructions in the turf structure as
described in reference to the figures of the present disclosure.
FIG. 4A illustrates the construction of one type of grass-like
structure for use as an artificial grass blade. A length of
polyethylene or other material of width "W" is sliced through in
places 38 as indicated. The material is then rolled up, or
pre-stressed to automatically roll up, as indicated in FIG. 4B, and
when sewn into an artificial turf backing it resembles a blade of
grass.
[0023] The granules 24 made by grinding up used tires are an
example of resilient material that can be used as an infill. Other
materials that provide a shock absorbing layer are also included in
the present invention, including mixtures of resilient and
non-resilient granules, such as a mixture of sand and rubber
granules, etc.
[0024] While the present invention has been described herein with
reference to particular embodiments thereof, a latitude of
modifications, various changes and substitutions are intended in
the foregoing disclosure, and it will be appreciated that in some
instances some features of the invention will be employed without a
corresponding use of other features without departing from the
spirit and scope of the invention as set forth in the appended
claims.
* * * * *