WO2002022960A1

WO2002022960A1 - Method for constructing a field of artificial grass and such a field of artificial grass

Info

Publication number: WO2002022960A1
Application number: PCT/NL2001/000669
Authority: WO
Inventors: Roelof Guido Benning; Jan Frans Marie Geerts
Original assignee: Tapijtfabriek H. Desseaux N.V.
Priority date: 2000-09-15
Filing date: 2001-09-12
Publication date: 2002-03-21
Also published as: NL1016193C2; AU2001294398A1

Abstract

The present invention relates to a method for constructing a field of artificial grass, comprising the steps of A removing the earth from a piece of land to a first level below the final surface level B laying a draining system on or in the bottom of said stripped piece of land, if necessary C filling the stripped piece of land with a base course to the final surface level, and D inserting fibres into said base course, wherein only synthetic fibres are used, wherein at least one end of each of said synthetic fibres extends above the final surface level.

Description

Method for constructing a field of artificial grass and such a field of artificial grass.

The invention relates to a method for constructing a field of artificial grass. From NL-A-8602514, which was filed by the present applicant, it is for example known to use mats for this purpose, on the upper side of which mats synthetic fibres resembling natural grass are present. The use of mats has several drawbacks. Especially in those cases where the field of artificial grass in question is intended for the game of soccer, the mat will be exposed to substantial shearing forces as a result of the sliding-tackles that are made thereon. As a result thereof the mat may detach from the underlying ground. In many cases, moreover, the mat stands in the way of an adequate drainage. A recent development concerns the combining of artificial grass fibres and natural grass, wherein the artificial grass fibres are either present on a mat in the form of an open structure layer, as is the case in the present applicant's patent application EP-A-0 174 755, or inserted into the ground individually, as disclosed in EP-A-0 554 330. It will be understood that one of the specific advantages of the field of artificial grass is thus lost, since the natural grass will grow and require maintenance, this in contrast to artificial grass. Moreover, the underlying ground must be suitable for growing natural grass thereon, whereby in accordance with EP-A-0554330 the ground, from which a layer of earth has been removed before, is successively filled with a 35 - 20 cm thick sand bed and a 15 - 30 cm thick layer of nutrient medium, preferably consisting of humous sand. After the ground structure has thus been prepared, artificial grass fibres are mechanically inserted into the ground, and the upper course is seeded with natural grass, so that a combination of natural grass and artificial grass is obtained. It is an object of the invention to provide a method for constructing a field of artificial grass which requires a minimum amount of maintenance, which is firmly connected to the underlying ground and which moreover is remarkable for an excellent drainage.

Another object of the present invention is to provide a method for constructing a field of artificial grass, which field of artificial grass is suitable for playing outdoor sports such as soccer, hockey, tennis and the like thereon.

In order to accomplish the above objectives, the method according to the invention comprises the steps of:

A removing the earth from a piece of land to a first level below the final surface level

B laying a draining system on or in the bottom of said stripped piece of land, if necessary C filling the stripped piece of land with a base course to the final surface level, and D inserting fibres into said base course, characterized in

^• that only synthetic fibres are used in step D, wherein at least one end of each of said synthetic fibres extends above the final surface level.

As a result of the absence of natural grass, a field of artificial grass which requires a minimum amount of maintenance is obtained according to the present method, whilst on the other hand an excellent fixation of the fibres in the base course is obtained. Another result of the absence of natural grass is that there is no need to provide a combination of a sand bed and nutrient medium as described in EP-A-0 554 330. Finally, in those cases where natural drainage is inadequate, the draining system that is provided under the base course provides an adequate drainage of excess water. In addition, it should be understood that the present method does not use the so-called backing layer, into which the fibres are sewn. According to the present invention, the synthetic fibres are inserted into the base course in such a manner that the use of such a backing layer is not required. Within the framework of this invention, the term field of artificial grass is to be understood to mean a field which, except for undesirable natural growth, such as weeds, consists exclusively of synthetic fibres without natural grass seed being sown therebetween. Preferably, the method according to the invention comprises the features as defined in claims 2 - 12.

The invention furthermore relates to a field of artificial grass or a part thereof, comprising a granular base course, whose upper surface lies at surface level, as well as fibres extending into said base course, at least one end of which extends above said surface level.

The present invention furthermore relates to a field of artificial grass or a part thereof, comprising a granular base course, a upper course consisting of sand and/or rubber lying on top of said base course, whose upper surface lies at surface level, as well as fibres extending through said base course and said upper course, at least one end of" Which extends above said surface level. The advantages of such a field of artificial grass have already been explained in the above with regard to the method according to the invention.

Preferably, the field of artificial grass comprises the features as defined in claims 13 - 21.

The invention will now be explained in more detail by means of a description of an exemplary embodiment, wherein reference is made to the accompanying figure. It should be understood, however, that the present invention is by no means limited to such a special example, but that such an example is merely given by way of illustration. The figure is a cross-sectional view of a part of a field of artificial grass. The field of artificial grass has been constructed in ground 1 and substantially consists of three layers 2, 3, 4. Drainage layer 2 consists of gravel. Drainage layer 2, which is about 3 cm thick, effects an adequate drainage of excess rain water. Instead of gravel, drainage layer 2 could also comprise a drainage system with pipes, depending on the natural draining capacity of the underlying ground and on the climate in which the field of artificial grass is to be used. Base course 3 consists of earth which has become available upon stripping of the ground 1 and which has subsequently been screened, if desired. It is not necessary, therefore, to carry off the earth that has been removed. The base course 3 is about 12 cm thick. Fibres 5 have been inserted into said base course 3 in regularly spaced-apart relationship, in such a manner that said fibres extend in said base course 3 in the form of a U, wherein the free ends extend about 5 cm above the upper side of base course 3. The insertion of the fibres into base course 3 can take place in a simple manner, partly because the base course 3 consists of screened earth. Fibres 5 are built up of six or eight twisted-together filaments, for example, which fibres are known from EP-0648868, which was filed in the name of the present applicant, which fibres 5 may have been unravelled insofar as they extend above base course 3, so that twelve or sixteen filament ends per fibre are available. In certain embodiments it is desirable to use fibrillated fibres. In this example, an upper course 4 is present on top of base course 3, between said filament ends. Said upper course, which is about 3 cm thick, consists of sand and/or rubber. The rubber that may be used makes the substructure feel resilient, whilst the sand ensures a dense packing and thus a proper boring of the fibres into the ground. It is also possible, however, to leave out the upper course 4 and only use the base course 3, whose upper surface forms the surface level in such an embodiment. In the first place, the ground 1 has been stripped of earth to a depth of 18 cm for the purpose of constructing such a field of artificial grass. Gravel for the drainage layer 2 has been deposited on the bottom of the stripped part. The earth that was removed during said stripping operation has been screened and subsequently been deposited on drainage layer 2 as base course 3. Since base course 3 consists of screened earth, fibres 5 can be inserted into base course 3 without any difficulty. In certain embodiments it may be desirable for the base course 3 to comprise rubber and/or sand in addition to the earth, which earth may have been screened. Subsequently, the ends of the above- discussed special fibres 5 are unravelled, thus forming twelve or sixteen filaments per fibre. Finally, an upper course 4 is brushed between the filaments, if desired. In order to prevent undesirable growth of weeds, fungi, bacteria and other organisms, it is desirable in certain embodiments to incorporate growth retarding agents, such as herbicides, fungicides and the like in the upper layer.

Claims

1. A method for constructing a field of artificial grass, " comprising the steps of A removing the earth from a piece of land to a first level below the final surface level B laying a draining system on or in the bottom of said stripped piece of land, if necessary C filling the stripped piece of land with a base course to the final surface level, and

D inserting fibres into said base course, characterized in that only synthetic fibres are used in step D, wherein at least one end of each of said synthetic fibres extends above the final surface level.

2. A method according to claim 1, characterized in that step C is substituted for step C, which step C comprises the filling of the stripped piece of land with a base course to a second level between said first level and the final surface level, and in that an additional step E is carried out after step D, which step E comprises the provision of an upper course on top of the base course to the final surface level.

3. A method according to claim 2, characterized in that the upper course according to step E comprises a particulate' material , which gives the field of artificial grass the damping power that is required for practising the intended sports activity thereon.

4. A method according to claims 2 - 3, characterized in that said upper course according to Figure E comprises sand and/or rubber.

5. A method according to claims 2 - 4, characterized in that the bottom side of the base course according to step C lies at a level of 5 - 25 cm below the final surface level.

6. A method according to claims 2 - 5, characterized in that after step D the ends of the synthetic fibres project 2.5 - 8 cm above the second level according to step C.

7. A method according to any one of the preceding claims, characterized in that the base course according to step C, C comprises earth.

8. A method according to claim 7, characterized in that said earth originates from the stripped part according to step A.

9. A method according to any one of the preceding claims, characterized in that said earth is screened before step C, C is carried out.

10. A method according to any one of the preceding claims, characterized in that the base course according to step C, C furthermore comprises rubber and/or sand.

11. A method according to any one of the preceding claims, characterized in that the synthetic fibres according to step D each comprise at least three filaments, whose ends extend above the final surface level .

12. A method according to any one of the preceding claims, characterized in that the spacing between synthetic fibres lying adjacently to each other ranges between 0.5 cm and 1.5 cm.

13. A field of artificial grass or a part thereof, comprising a granular base course, whose upper surface lies at surface level, as well as synthetic fibres extending into said base course, at least one end of which extends above said surface level.

14. A field of artificial grass or a part thereof, comprising a granular base course, an upper course consisting of sand and/or rubber lying on top of said base course, whose upper surface lies at surface level, as well as synthetic fibres extending through said base course and said upper course, at least one end of which extends above said surface level .

15. A field of artificial grass or a part thereof according to claims 13 - 14, characterized in that the thickness of said base course ranges between 5 cm and 25 cm and in that the thickness of the upper course that may be present ranges between 1.5 cm and 6 cm.

16. A field of artificial grass or a part thereof obtained by - implementing the method according to any one of the claims 1 - 12.

17. A field of artificial grass according to claims 13 - 16, characterized in that said synthetic fibres are made of a material from which artificial grass is made.

18. A field of artificial grass according to claims 13 - 16, characterized in that said synthetic fibres are made of a natural material or another material which is resistant to wear when loaded mechanically.

19. A field of artificial grass according to claims 13 - 18, characterized in that the density of said synthetic fibres per unit area is greater in those areas where the field is played on more intensively.

20. A field of artificial grass according to claims 15 - 19, characterized in that said synthetic fibres are provided with protrusions along substantially their entire length, or in that said synthetic fibres are twisted together so as to obtain an improved anchoring of the fibres in said base course and/or said upper course.

21. A field of artificial grass according to claims 13 - 20, characterized in that said synthetic fibres are loop-shaped or V-shaped once they are inserted into the base course and/or the upper course.

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