Synthetic turf

Details Synthetic turf Synthetic turf

2001-11-20

2004-04-20

Jones, Deborah (Department: 1775)

Stock material or miscellaneous articles

Pile or nap type surface or component

With particles

C428S017000, C428S095000, C428S327000, C428S143000, C428S167000, C428S220000, C428S317900, C428S332000, C428S402000

Reexamination Certificate

active

06723412

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is directed toward improved synthetic grass surfaces. The invention is more particularly directed toward improved, synthetic grass sports surfaces. The invention is also directed toward a method of making an improved synthetic grass sports surface, and an apparatus for carrying out the method. The invention is further directed toward an improved synthetic grass sports surface having playing lines formed in its top surface and to a method of making the lined surface.
2. Description of the Prior Art
Synthetic grass sports surfaces are well known. They are used to replace natural grass surfaces which do not stand up well to wear and which require a great deal of maintenance. Also, natural grass surfaces do not grow well in partly or fully enclosed sports stadiums. The synthetic grass surfaces stand up to wear much better than the natural grass surfaces, do not require as much maintenance, and can be used in closed stadiums. Some synthetic grass surfaces comprise rows of strips or ribbons of synthetic material, extending vertically from a backing mat with particulate material infilled in between the ribbons on the mat. The ribbons of synthetic material usually extend a short distance above the layer of particulate material and represent blades of grass. The particulate material usually comprises sand, as shown by way of example in U.S. Pat. Nos. 3,995,079, 1976, Haas, Jr. and 4,389,435, 1983, Haas, Jr., but can comprise other materials or a mixture of sand and other materials, as shown in U.S. Pat. No. 4,337,283, 1982, Haas, Jr., by way of example. The particulate material provides resiliency to the synthetic grass surfaces, and the surfaces are often laid on a resilient pad to provide further resiliency to the surfaces.
The known sand-filled synthetic grass sports surfaces have some disadvantages. The surfaces usually become hard after extended use because the sand, between the rows of ribbons, becomes compacted. Compacting occurs, in part, because the rows of ribbons are quite close together, and the sand cannot spread a great deal laterally during use. Compacting also occurs, in part, because the close spacing of the ribbon rows traps debris, worn and torn off the ribbons, in the sand, even when the particulate material comprises rounded sand particles. With an increase in compaction, the surface becomes progressively harder and less resilient. The performance of the surface is shortened, and it has lessened playing qualities. The surfaces also become harder after use because the resilient pads, if used, slowly collapse under use, becoming denser. Removal and replacement of the compacted particulate material, or even loosening of it, is difficult because of the close spacing of the rows of ribbons. It can require expensive equipment to remove and replace the compacted particulate material, or even loosen it, and this adds to the cost of maintaining the surface.
Another problem with the known synthetic grass sport surfaces is the problem of drainage. Water flow through the surfaces has generally been slow. The ribbons are usually attached to the mat by tufting them through the mat, and then the bottom of the mat is coated with a bonding layer to bond the ends of the ribbons to the mat. The bonding layer is non-porous. To provide adequate porosity, the coated mat is punctured to provide holes. However, the particulate material often flows into these holes, plugging them up and thus reducing the drainage qualities of the surface. The loss of the particulate material into and through the holes also requires that it be replaced on top of the mat, adding to the cost of maintaining these surfaces. Compaction of the surface also inhibits drainage.
The known synthetic surfaces also have relatively poor playing qualities. When infilled with rounded sand particles more rounded than angular, because the rounded particles are thought to compact less and cause less abrasion, the surface can become too slippery, particularly when the ribbons are only slightly longer than the thickness of the layer of particulate material. Also, the closely spaced fine ribbons, if penetrated, can tightly grip the cleats and do not tear as easily as grass, thus making release of the cleats more difficult and making playing on the surface more difficult and dangerous than when playing on grass. If a player's cleats do not release easily, he could injure his leg, ankle, or knee. It has also been found that if the athlete's cleat penetrates a seam area, the chances of the shoe not being released or allowed to pivot is much greater.
The known synthetic surfaces, with closely spaced rows of ribbons, also increase the speed of a rolling ball from the speed with which it rolls on natural grass. The closely spaced ribbons create an almost solid, low resistance surface for a rolling ball, thus adversely affecting the playing qualities of the surface. If the surfaces are employed with a resilient base pad, balls bounce more on the surfaces than on grass, subtly changing the nature of the game. The low resistance surface also makes it more slippery for tennis players.
The known surfaces have other disadvantages. Usually the ribbons employed are quite narrow, and they can curl creating an appearance unlike grass. The narrow ribbons also abrade easier, creating debris that can increase compaction of the surface. The close spacing of the ribbon rows also causes skin abrasion on players falling or sliding on the surfaces.
SUMMARY OF THE INVENTION
It is the purpose of the present invention to provide an improved synthetic grass sports surface that is more resilient, and remains more resilient for a longer period of time, than known synthetic grass surfaces.
It is another purpose of the present invention to provide improved synthetic grass sports surfaces that have improved drainage properties and improved playing properties.
It is yet another purpose of the present invention to provide improved synthetic playing surfaces that are relatively less expensive to manufacture, to install, and particularly to maintain.
It is still another purpose of the present invention to provide synthetic playing surfaces that are less abrasive, easier to mark with lines, and easier to seam.
It is another purpose of the present invention to provide a method for making one embodiment of the present invention having improved drainage properties and a machine for carrying out the method.
In accordance with the present invention, it has been found that an improved synthetic grass surface can be provided by employing relatively widely spaced rows of ribbons. The wider spacing of the ribbon rows reduces the compaction of the infill that normally occurs with more closely spaced rows, thus extending the life of the surface with respect to resiliency. Reduced compaction also ensures better drainage. Wider row spacing should also ensure less wear and abrasion of the ribbons, extending the life of the surface and minimizing the formation of ribbon debris which affects compaction and drainage. Wider row spacing also allows better cleat penetration and allows the cleats to release easier, thus improving the playing qualities and reducing the risk of injury. Wider ribbon row spacing can also cause balls on the surface to roll more like they roll on grass, thus improving playing qualities. Wider ribbon row spacing also makes it easier to loosen the particulate material if it does start to compact, and to clean or replace it. Wider ribbon row spacing also reduces abrasion to the players when contacting the surface. Wider ribbon row spacing can make it easier to seam the surface.
In accordance with the present invention, it has also been found that an improved synthetic grass surface can be provided by providing ribbons having a length about twice as long as the spacing between the rows of ribbons. The present invention employs ribbons that are quite long compared to the ribbons now employed. The longer ribbons allow a thicker layer of particulate material to be used which can eliminat

Affiliated with

Also associated with

Rating

Synthetic turf does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Synthetic turf, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Synthetic turf will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3222559