CZ291161B6 - Synthetic grass surface - Google Patents

Abstract

In the present invention there is disclosed a synthetic grass surface (1) having a flexible backing member (3) and parallel rows (5) of synthetic ribbons (7), representing blades of grass, projecting upwardly from the backing member. A particular material (9) being represented by a mixture of silica sand and cryogenically ground crumb rubber is laid on the backing member (3) of the synthetic grass (1), and it is preferred when the thickness of the particulate material (9) is at least two-thirds the length of the ribbons (7).

Description

Technical field

The present invention relates to improved artificial grass surfaces. More specifically, it relates to improved artificial grass sports surfaces. The invention is further directed to an improved artificial grass sports surface with marked lines on the surface and to a method for preparing the line marked surfaces.

BACKGROUND OF THE INVENTION

Artificial grass sports surfaces are well known. They are used as a replacement for natural grass surfaces that are easy to wear and require considerable maintenance. Natural grass surfaces also do poorly in partially or fully enclosed sports stadiums. Artificial grass surfaces are more resistant to wear than natural grass surfaces, do not require much maintenance and can also be used in enclosed stadiums. Some artificial grass surfaces have rows of strips or strips of artificial material vertically extending from the backing mat, the gaps on the backing mat between the rows of strips being filled with bulk material. The strips of artificial material usually protrude a shorter section of their length above the surface of the bulk material and represent grass blade. Typically, the bulk material is sand as in U.S. Pat. Nos. 3,995,079, Haas Jr., 1976, and US 4 389 435, Haas Jr., 1983, but may also include other materials or a mixture of sand and other materials, as exemplified by e.g. in U.S. Pat. No. 4,337,283, Haas Jr, 1982. Loose material provides elasticity to artificial grass surfaces, and these surfaces are often placed on resilient pads to increase surface elasticity.

Existing sand-filled artificial grass sports surfaces have some disadvantages. After prolonged use, the surfaces of the garment harden because the sand compacts between the rows of strips and becomes compact. This is partly because the rows of strips are close together and the sand cannot move sideways sufficiently under operating conditions. The compaction is partly due to the fact that the close proximity of the rows of strips retains in the sand fragments of strips caused by abrasion and tearing, even if the bulk material contains rounded particles of sand. With the compacting process, the surface gradually hardens and loses its elasticity. The service life of the surface will be shortened and its sporting quality will deteriorate. During use, the surfaces harden because the elastic pads slowly collapse and their density increases. The removal and replacement of the compact bulk material and its mere loosening are made more difficult due to the close proximity of the rows of these strips. Sometimes removal and replacement, as well as mere disintegration of a compact bulk material, may require costly equipment and may increase the cost of surface maintenance.

Another problem of known artificial grass sports surfaces is dewatering. Water generally flows slowly through these surfaces. The strips are usually attached to the mat by the tufting technique and then the bottom of the mat is coated with a coating layer that connects the ends of the strips to the mat. This coating layer is not porous. To provide the necessary porosity, the coated mat is perforated to form holes. However, the particulate material often flows into these openings, clogging them and impairing the drainage ability of these surfaces. The flow of these particles into the holes makes it necessary to replace the top of the mat and thereby increase the maintenance costs of these surfaces. The compacting of this surface also prevents its drainage.

Known artificial surfaces also have relatively poor sporting properties. When the rows are filled with sand particles that are round rather than square because, in the opinion that the round particles are less compact and less abrasive when falling, the surface becomes too slippery, especially when the strips are only slightly longer than the thickness of the bulk material layer . Fine stripes of artificial grass in densely cramped rows molds on the soles of sports shoes hold firmly when pressed

They do not tear as easily as grass, making it difficult to release these moldings, and playing on these surfaces becomes more difficult and dangerous. If moldings on the player's soles are not easily released, injury to the player's lower extremities, knee or ankle may result. It has also been found that when these moldings on an athlete's shoe are buried in the mat joint area, the likelihood that the shoe 5 will not loosen or rotate around the point of contact is much greater.

Known artificial surfaces with strips of grass in densely cramped rows also increase the speed of a rolling ball compared to the speed at which it rolls on natural grass. The densely cramped strips create a near-solid surface with low resistance for the rolling ball, thereby adversely affecting the 10 sports surface qualities. When using surfaces deposited on an elastic backing, the balls bounce off the surface more than in the case of natural grass, and thus slightly change the character of the game. For tennis players, less resistance also makes surfaces more slippery.

The known surface also has other drawbacks. The strips used tend to be quite narrow, as a result of which they curl and do not resemble grass. The narrow strips are also more easily subject to scuffing and the resulting fragments increase the compactness of the surface. Densely cramped rows of stripes also cause scratches to players when they fall or slip on the surface.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide improved artificial grass sports surfaces that are more elastic and resilient to remain longer than known artificial grass surfaces.

Accordingly, it is an object of the present invention to provide an artificial surface having a flexible substrate and parallel rows of artificial strips representing blades of grass leaves pointing upwardly from the substrate, the surface comprising an essentially thick layer of bulk material deposited on the substrate. substantially in an upright position relative to the substrate, and the particulate material is a mixture of resilient and hard bulk material, which is a mixture of cryogenically ground rubber and sand.

Another object of the present invention is to provide an improved artificial grass sports surface, wherein the layer thickness of the bulk material is at least 2/3 of the length of the strips from the substrate to the free ends of the strips.

According to the present invention, the surface is provided with an improved filler layer of bulk material, which is a filler of quartz sand and ctyogenically ground rubber particles. Cryogenically ground rubber particles are easier to wet than rubber particles milled by another technique and thus allow faster dewatering. Cryogenically ground rubber has less square particles than 40 otherwise ground rubber and has less tendency to bind microscopic air bubbles. The ratio of sand to rubber may vary according to the end use of the surface, the more elastic the surface is required, the more rubber must be. This reduces the tendency of the rubber particles to float to the surface when flooding the pitch, which could result in loss of material and a change in the sporting properties of the surface. Cryogenically ground rubber means rubber particles prepared by removing 45 rubber from used tires by cryogenic grinding of rubber. Disintegration of the rubber in the frozen state leads to the formation of rubber particles with smoother and less rugged surfaces than that produced by non-cryogenic processes.

It is another object of the present invention to provide improved artificial grass sports surfaces that are better dewatered and have better sports characteristics.

It is another object of the present invention to provide improved artificial sports surfaces having relatively lower manufacturing costs, lower laying costs, and particularly maintenance.

-2GB 291161 B6

Yet another object of the present invention is to provide artificial sports surfaces in which it is relatively less expensive to manufacture, install and particularly maintain.

Yet another object of the present invention is to provide artificial sports surfaces that are less abrasive, easier to line, and whose parts are easier to join.

According to the present invention, it has been found that improved artificial grass surfaces can be achieved by using larger spacing between individual rows of strips. The wider spacing of the rows of strips reduces the compacting of the loose fill between rows that normally occurs with more cramped rows, thereby extending the surface life in terms of elasticity. Lower density also ensures better drainage. Wider strip lines also contribute to less strip wear and abrasion, thereby extending surface life and minimizing the formation of strip fragments affecting compaction and drainage. Wider rows also allow better penetration of the moldings on the outsoles and easier release, which improves the quality of the game and reduces the risk of injury. Wider lines also result in the ball rolling in a way that is more similar to the movement of the ball on natural grass, which increases the quality of the game. The wider rows also make it easy to disassemble bulk material that begins to compact, clean and replace. The wider strip lines also reduce the abrasion of the players that have come into contact with the surface. Wider rows can facilitate joining of surface parts.

According to the present invention, this surface is prepared to form lines that are distinguished on the playing field according to the rules of the sport. An example of such lines is the lines dividing the football pitch, which divide the pitch at regular intervals. These lines are generally applied to the surface of the ground by ground chalk or other similar marking material. According to the invention, the surface may be provided with permanent lines embedded in the surface. They are inserted when joining the individual parts of the underlying surface layers.

BRIEF DESCRIPTION OF THE DRAWINGS

After a general description of the nature of the invention, reference is now made to the accompanying drawings which illustrate, by way of illustration, a preferred embodiment of the invention:

Figure 1 is a cross-section of an artificial grass surface according to the invention.

Figure 2 is similar to Figure 1 and shows the free ends of the strips in a natural lodged position.

Figure 3 is a side view of the applicator.

Figure 4 shows a cross-section along line 4-4 in Figure 3.

Figure 5 shows a top view of the machine.

Figure 6 shows a detailed top view.

Figure 7 shows a perspective view of a substrate after coating with a covering material.

Figure 8 shows an exploded end view of the sports surface joint, wherein the joint forms the marked signal line of the sports field.

Figure 9 shows an overall view of the joint of Figure 8.

DETAILED DESCRIPTION OF THE INVENTION

The artificial grass surface 1 according to the invention has, as shown in FIG. 1, a thin and flexible substrate 3 with parallel rows of strips 5 or strips 7 extending upwardly from the substrate 3. On the substrate 3 lies a relatively thick layer of filler bulk material 9, which keeps the strips 7 in an approximately upright position on the substrate 3.

As can be seen, the flexible substrate 3 can consist of two layers 11 and 13 of the substrate. The backsheet 11 may be a woven or needled polypropylene fabric. The topsheet 13 may also be a woven or needled polypropylene fabric. Plastic strips or strips 7 are tufted in the substrate 3 and pass through both layers as shown in Figure 2.

Although the substrate 3 has been bilayered, it can also be formed from a single layer or vice versa from multiple layers, for example three. The one or more layers in the substrate 3 may be a needled woven fabric 15 to improve dewatering, but when only one layer is used, it must be relatively thick. At least one of the layers 11 in the substrate 3 may be needled by crimped fibers (flw) 15, as shown in Figure 2, to remove moisture through the layer. These crimped fibers further improve surface drainage.

The strips 7 are made of suitable synthetic plastics extruded into a tape that is relatively wide and thin. The preferred material is polyethylene, which is soft and has good wear resistance. However, polypropylene can also be used to prepare the strips. The tape may have a width ranging from one quarter inch (0.635 cm) to one inch (2.54 cm), but a width of about half inch (1.27 cm) is preferred. The tape thickness is between 65 and 150 microns.

Strips 7 are cut from the extruded strip and tufted in parallel rows 5 in the substrate 3 by tufting them in parallel rows 5. Two to eight strips (0.7874 strips per cm to 3.15 strips per cm) are sewn per inch of stripe row and is preferred number of 4 strips per inch (1,575 strips per cm). These strips are mechanically spun or split to a width of one eighth, an inch (0.3175 cm) or more.

Spinning, which is carried out mechanically in the production of the tape, results in a hair-like strip because the resulting fibers are interconnected.

The distance between the rows of strips depends on the type of sport for which the course is intended. For example, the 35 moldings on the soles of shoes for various athletic disciplines are about three-quarters of an inch apart. Moldings on soles of American football or European football shoes may be wider than moldings on basketball shoes. The distance between rows of strips depends on the type of sport for which the pitch is intended and is the result of the distance between the moldings on the players' shoes. Similarly, it is believed that for sports such as horseback riding, considerable distances of 40 between the rows will be needed due to the broader hooves of horses. For equestrian disciplines, it is anticipated that gaps between rows of up to 2 and a quarter inches (5,715 cm) will be required with proportionally longer strips of artificial grass up to 5 inches (12.7 cm).

Relatively wide strips are preferred, at least half an inch wide, because the wider strips do not twist as easily as narrower and are more resistant to wear and abrasion. The wider strips 7 also better cover and retain the loose filler material in the lodged position as shown in Figure 2. At least the free ends of the strips 7 are fiberized over the bulk material layer 9, giving the impression of a more dense grassing of the surface. The ends of the strips can be further spun using a steel brush and other mechanical spinning agents even after the installation of artificial turf and loose filler.

Here, too, it is possible to combine strips of different thicknesses. Depending on the intended use of the pitch, for example, stiffer and softer stripes can be combined to control the ball rolling speed. The stiffer strips have more memory, which, in comparison with the softer ones, returns them to an upright position.

-4GB 291161 B6

An example of such a blend is a thicker strip having a weight of 11,000 denier and a thickness of about 100 to 120 microns. The softer strip could be from 5700 denier more and 80 micron thick. Any combination of these stiffer and softer strips will result from the special requirements for the course. The ratio of the stiff and soft strips may be 1: 1. These stiffer and softer strips may alternate or be sewn together.

The rows 5 of the strips 7 are spaced at a distance A that is between five eighth of an inch and two and a quarter of an inch. These gaps between rows depend on the sporting purpose of the course, with narrower gaps used for surfaces designed for less demanding physical activities, such as golf greens, and larger spacings used when greater physical strain is expected, such as horse racing.

The relatively wide gaps between the rows of strips have several advantages. The wide spacing between the rows reduces the tendency of the surface to compact. With reduced compactness, surface drainage is improved. Wide gaps also reduce the amount of strip preparation material. Wide gaps further improve the sporty surface quality. A player doing sports on this surface has the advantage of increasing the grip of the shoe, since its moldings on the sole better sink into the bulk material between the rows of strips. At the same time, the moldings are easier to release because there is more space between the rows to allow loose material to be dislodged. The wide spacing between the rows also facilitates loosening, cleaning and even replacement of loose filling material. Sufficient space between the rows allows pneumatic uncoupling of this material and cautiously loosening it. Loose and loosened material can be removed, cleaned, debris-free and returned to the substrate layer between rows. The service life of the surface is prolonged and the cost of replacing the bulk material is reduced. The wide spacing between the rows also makes it easier to stitch adjacent parts of the surfaces without producing significant seams, as there is more room for these joints.

With regard to the length of the strips, the length L of the strips 7 is the distance between the substrate 3 and the ends of the strips 7 and is at least twice the distance (gap) A between the rows 5 of the strips and is preferably 3 to 6 times. The length of the L strips is between one and a quarter inches (3.175 cm), but preferably between three inches (7.62 cm) and five inches (12.7 cm), with shorter strips used for surfaces with smaller row spacing and longer strips are used in case of larger gaps between rows. Longer strips (as compared to previously used) allow the use of a thicker padding layer 9, thereby providing a more flexible layer not requiring resilient pads. This eliminates the cost of this washer and its installation. The thicker filler layer 9 allows for better drainage, since a higher water level is generated and thus a higher pressure altitude is created on the ground surface. Longer strips can also provide a greater length of strips above the padding even with a thicker layer of the bulk padding, with loose strips above the padding protecting the player from falling off with sand and other bulk material when dropped. The strips may overlap the filler layer in lengths from one quarter of an inch (0.635 cm) to one inch and a half (3.81 cm). Depending on the end use of the surface, the thickness of the padding layer may be from one inch (2.54 cm) to four inches (10.16 cm). The padding layer typically has a thickness T of about two-thirds of the length of the strips L.

Preferably, the layer 9 comprises a mixture of hard rock sand such as silica and cryogenically ground rubber pulp. Cryogenically ground rubber pulp is preferred because its particles are more rounded, reducing abrasion and preventing compaction. Less angular rubber particles also become easier to wet, which facilitates dewatering. In addition, the particles have less tendency to flush away when the playground is flooded because the rounded particles are less bound to microscopic air bubbles. The particle size can vary between 4.7 mm (4 mesh) and 0.204 mm (70 mesh), but is preferably between 1 mm (15 mesh) and 0.5 mm (30 mesh) in the case of sports where players are contact with the surface is exposed to the risk of chafing and between 4.7 mm (4 mesh) and 0.5 mm (30 mesh) where this is not the case. The quartz sand may be replaced by a sorted hard rock pulp, a hard plastic of a higher weight, or other loose sand type material. Cryogenically ground rubber pulp may be replaced by other elastic materials such as cork, styrene, EPDM rubber, neoprene or

Other similar materials when the shape of the particle resembles the shape of cryogenically ground rubber.

In some cases, some or all of the resilient materials may be replaced by other materials with specific tasks. As an example, perlite may serve as a substitute for elastic material, which additionally reduces compaction and possibly absorbs moisture.

The mixture of sand and elastic material may have different compositions depending on the intended use of the surface. When it requires more flexibility, more rubber is used. With relatively thick layers, the bulk material layer 9 can be divided into two layers, of which the bottom 17 on the substrate 3 of Figure 2 has smaller particles and the top layer 19 has larger particles, which facilitates drainage. The particle 10 in the backsheet 17 may mainly comprise sand of about 0.398 mm (40 mesh) to about 0.204 mm (70 mesh). In this case, the topsheet 19 comprises larger sand particles in conjunction with a 30 mesh grain rubber particle. The predominant or exclusive use of sand in the bottom layer reduces the cost of the surface.

The surface 1 is prepared by sewing the strips 7 into the substrate 3 in rows 5 spaced from five to eight inches (1.5875 cm) to two and a half inches (6.35 cm), with 2 to 8 strips per sewn inch. After sewing the strips 7, a material can be applied to the underside of the substrate to adhere the strips to the substrate. In this way, the entire substrate can be coated.

One embodiment of the present invention using a porous substrate is preferred, but only some portions of the substrate are coated to improve drainage and reduce costs.

In this embodiment, after sewing the strips 7, the substrate 3 passes through the top side down with a standard device for coating the underside of carpets. This applicator 31 schematically shown in Figures 3, 4, 5 and 6 has a support plate 33 on which, as it passes through the machine, the substrate 3 of the sewn-on strip is displaced. There is a device (not shown) for moving the substrate 3 along the support plate 33 from one side to the other, as shown by arrow 34 in Figure 3. The support 3, when moved on the support plate 33, passes under the ridge-shaped device 35 with a row of parallel fingers. 37 resting from above on the base of the substrate 3 against the support plate 33. The distance between the fingers 37 may be varied so that one finger covers the gap between each pair of adjacent 30 rows of strips of artificial grass strips on substrate 3. the beginning of the fingers 37 than their ends. There is an application device 40 which, prior to the spreading knife 39, applies coating material M to said comb device 35 over its entire width. As the substrate 3 is moved to the right under the application device as shown in Figure 3, the coating material M to the spreading knife 39 is also carried along with the substrate, where it is spread and laid on narrow zones 41 35 of substrate 3 not covered by fingers 37. the strips 5 and the ends of the strips in these rows are covered with a coating material M which adheres the strips 7 to the substrate 3. The fingers 37 prevent the coating material M from being applied to the narrow strips 43 of the substrate 3 adjacent the rows of strips 5. 37, the backside of the substrate 3, as shown in FIG. 7, is provided with strips 45 of coating material M which cover the rows 40 of the strips 5, leaving adjacent zones 43 on the substrate 3 exposed by finger action to form a very porous and well draining surface. The coating provided by the applicator has a much lower material consumption than the coating over the entire surface of the substrate, thereby providing additional material savings that make this surface cheaper.

Application can also be accomplished by methods other than the coating of rows of strips described above. For example, a plurality of nozzles can apply thin lines of coating to the rows of strips, and the spreading knife can press them onto the underside of the mat while leaving relatively wide and long portions of the substrate uncovered and therefore functional during dewatering. Coating rollers of different diameters can also be used for coating.

The lines can be made to mark the playing surface on the playing surface by joining adjacent edges of the sports surface parts with a specific joint. As shown in Figure 8, a joint strip 5L is inserted below the adjacent but spaced apart edges 53 and 55 of adjacent surface portions 57 and 59. The joint strip 51 has stitched strips 63 in its center portion 65, but no strips

291161 B6 does not have on its wide side edges 67 and 69. The central panel 65 is located between the edges 53 and 55 of the surface panels 57 and 69, wherein the sewn strips 63 in the central panel 65 may have different colors and / or different lengths the strips 7 of the surface parts 57 and 59, thereby forming a line 71 indicating the playing surface. The wide side flanges 67 and 69 of the connector 51 may be needled on the crimped pile fabric. Adhesive A is applied to the upper side of the wide side skirts 67 and 69 to adhere the overlying surface parts 57 and 59. The curled pile fabric facilitates the bonding of the joint strip 51 to the surface portions 57 and 59. The joint strip 51 is underneath The central panel 65 can be coated with a coating material M, preferably also under the side flanges 67 and 69. This prevents leakage of the adhesive A used on the joint by the strip 51 and possible sticking to the substrate.

After joining the strip 51 to the surface parts 57 and 59, as shown in Figure 9, and hence joining the parts, the strips 63, due to their different appearance compared to the strips 7 on the surface of the parts 57 and 59, represent a line 71.

Also used is a surface with long strips of artificial grass of at least four and a half inches (11.43 cm), the thickness of the bulk material layer corresponding to this stripe length. This surface can be used for growing plants. The loose filler material may be a crop growth material, for example a moisture retention material for the plants and a material that allows the development of a strong root system. The bulk material layer may be comprised of one or more layers of the support material. In some cases, the support material may have a specific gravity less than water, and as the backsheet below the topsheet remains in place and is not carried away by water. These surfaces would be particularly useful in arid areas. The irrigation tubes can be laid directly in the bulk material layer. The backing layer may have a porosity such that it retains moisture in the bulk material and promotes plant growth. The strips would minimize the amount of bulk material that would blow winds in windy areas.

A pitch using long strips and thick layers of loose material containing cryogenically ground rubber could be used as an environment for growing natural grass, with its root systems developing in the loose material.

PATENT CLAIMS

Claims (2)

Artificial grass surface (1), characterized in that it has a flexible substrate (3) and parallel rows (5) of artificial strips (7) representing blades of grass leaves and pointing upwards from the substrate (1), the surface necessarily comprising a thick layer of bulk material (9) deposited on the substrate, wherein the bulk material (9) keeps the strips substantially upright relative to the substrate (3), and the particulate material (9) is a mixture of cryogenically ground rubber and sand. Surface according to claim 1, characterized in that the thickness of the layer (T) is at least 2/3 of the length (L) of the strips (7) from the substrate (3) to the free ends of the strips (7).