DESCRIPTION

The present invention relates to a resilient carpet, to a resilient carpet for use in combination with a grass carpet, and to its production method.

Said resilient carpet is usable in particular for sports underflooring. More particularly, the invention is suitable for use as a foundation for synthetic or natural grass coverings, for example for football pitches, to provide them with correct resilience and draining.

Another very important application is in building construction as a thermal and acoustic insulant, or as anti-trauma protection in the field of recreational and sporting activities.

The foundation for synthetic grass coverings constitutes a fundamental element in attaining the performance required to ensure suitability of a playing field.

It must also ensure correct drainage for rain water which could otherwise compromise play.

Drainage normally takes place vertically, i.e. water penetrates vertically and directly into the grass covering and into the foundation carpet and is discharged directly into the ground.

Otherwise drainage can take place horizontally, with horizontal water transportation by suitable channelling.

Resilient foundations for grass coverings are known, formed from SBR granules obtained by shredding used tyres, normally mixed or aggregated with resins. An object of the invention is to provide a resilient carpet of simple construction.

Another object is to provide a carpet of low cost and easy to lay. A further object is to ensure a considerable draining effect.

Another object is to ensure that the carpet satisfies the requirements of the sporting federations, complies with legal regulations and passes all those checks required for the various certificates and validations.

These and further objects are attained, according to the present invention, by a resilient carpet comprising a plurality of pockets filled with granular material; said pockets being formed by a lower first fabric layer and an upper second fabric layer which are joined together to form a plurality of tubular elements; characterised in that said granular material comprises ground vulcanized rubber; and by comprising at least one heating tape associated with said resilient carpet.

These objects are also attained by a method for producing a resilient carpet comprising the steps of: joining a lower first fabric layer to an upper second fabric layer to form a plurality of adjacent tubular elements, by sewing or welding or directly on a loom during weaving; locating a heating tape on said upper second fabric layer; filling said tubular elements with granular material comprising vulcanized rubber.

Further characteristics of the invention are described in the dependent claims. The characteristics and advantages of the present invention will be apparent from the ensuing detailed description of one embodiment thereof, illustrated by way of non-limiting example in the accompanying drawings, in which:

Figure 1 is a schematic view, seen from above, of a resilient carpet before filling, in accordance with the present invention;

Figure 2 is a schematic view, seen in profile, of a resilient carpet before filling, in accordance with the present invention;

Figure 3 is a schematic view, seen in section, of a resilient carpet after filling, with a sheet of impermeable fabric material below it, in accordance with the present invention;

Figure 4 is a schematic view, seen in section, of a resilient carpet after filling, in accordance with the present invention;

Figure 5 is a schematic perspective view of a resilient carpet after filling, without the upper layer, in accordance with the present invention;

Figure 6 is a schematic sectional view of a natural grass carpet combined with a resilient carpet, in accordance with the present invention;

Figure 7 is a schematic sectional view of a synthetic grass carpet combined with a resilient carpet, in accordance with the present invention.

With reference to the accompanying figures, a resilient carpet according to the present invention comprises a lower first fabric layer 10 and an upper second fabric layer 1 1 . The two fabric layers 10 and 11 are joined together, preferably by a lateral stitch seam 12 along a long side of the fabric, and straight stitch seams parallel to each other and preferably equidistant, positioned transversely to the two fabric layers. These stitch seams form a plurality of tubular elements 14. The term "tubular element" denotes an article of elongated cylindrical shape, in this particular case in the form of virtually cylindrical elongated pockets positioned transversely to the length of the fabric and separated from each other by stitch seams 13.

The tubular elements 14 are separated from each other by the stitch seams 13 which form channels 15 both above and below the carpet. In this respect, a transverse space is formed both above and below the carpet, between the stitch seam and the crest of the adjacent tubular elements. These spaces enable water to drain both vertically and horizontally.

The distance between the various stitch seams is preferably between 1 and 10 cm, and more preferably between 2 and 5 cm.

The two fabric layers preferably have a width between 0.5 m and 4 m and can have any desired length.

The two fabric layers are preferably made of polyester non-woven fabric of weight about 100-400 g/m ² .

Alternatively the two fabric layers can be fabrics of synthetic or natural origin, obtained by calendaring or weaving.

As an alternative to the stitch seams, the fabric layers 10 and 1 1 , preferably of polyester, could be joined together to form the plurality of tubular elements 14 by thermowelding or ultrasound, or even more advantageously by forming the tubular elements and the closure of a long side directly on the loom during weaving, to form a single fabric, known by the name of double tech (double technique with tubular elements of predetermined width). The fabric can be obtained directly during weaving by interweaving weft and warp. Several equidistant tubular elements of the desired width are obtained in the weft direction.

A necessary characteristic to obtain good drainage is that the fabric is water permeable.

In particular cases one or even both of the fabric layers can be impermeable (for example polythene, PVC, fabrics made impermeable by spreading, adhesive-bonding, etc.). One of the fabric layers can also be combined with an aluminium sheet of a few tenths of a millimetre thick (adhesive-bonding it with glue or by thermowelding using an intermediate polyethylene sheet). With an aluminium sheet, in addition to providing an impermeable layer there is also a heat shield and a screen for electromagnetic waves, besides distributing heat over the entire surface if combined with the heating tape.

With the aforedescribed modifications particular characteristics are obtained for the carpet at the expense of vertical drainage and using only horizontal drainage through the upper channels 15.

A carpet of horizontal drainage type according to the present invention can also be formed by positioning below it a sheet of impermeable fabric material 16. In this case the horizontal drainage takes place along the channels 15 below the carpet and running along the fabric 16.

In an advantageous embodiment of the carpet, the upper second fabric layer 1 1 is formed with two superimposed layers 20 and 21 , each possibly of lesser weight than the layer 11 alone. A heating tape 22 is positioned within the space created between the layers 20 and 21.

The heating tape 22 consists of a multi-layer sheath of width 12-16 mm and overall thickness 0.4 mm, in which the active element is a C- shaped (double layer) double aluminium thin film conductor, with the openings physically closed and disposed at the upper and lower end, all covered and protected by two layers of high characteristic polypropylene of 25 μιτι thickness.

This sheath is preferably disposed in runs in a direction perpendicular to the tubular elements of the substrate, with a distance apart suitable for obtaining the desired heating power per square metre.

The heating tape 22 is powered at low voltage (< 48 V a.c.) by connection to a unit for regulating the feed voltage and consequently the tape temperature. Temperature sensors can also be provided to control the correct operation of the tape 22.

The carpet is produced by joining the fabric layers together along only three sides, leaving a long side non-stitched, for filling the tubular elements 14. If a heated carpet is to be produced, the heating tapes and the further fabric layer are positioned. Specifically, the tape 22 is disposed on the upper layer in an arrangement depending on the power to be obtained per square metre, and the electrical connection cables are fitted. Preferably, a tape 22 redundant to the first is also fitted for use if the first is interrupted. Alternatively, the power to be obtained per square metre can be split between two tapes 22, to provide greater versatility by activating one tape or the other, to reduce the consumed power and/or to obtain at least part of the heating if one tape is interrupted.

The heating tape 22 is coupled to the upper layer 11 of the tubular element structure of the system substrate by placing it on it and then gluing a further fabric layer (or aluminium sheet) to the substrate (while still at the flat stage, before filling the tubular elements); or thermowelding a further fabric layer (or aluminium sheet) to the substrate (while still at the flat stage, before filling the tubular elements) with interposition of a polyethylene sheet.

The two non-stitched flaps of the fabric layers are then slightly moved apart and the various tubular elements which form are filled with granular material.

The granular material is preferably granular SBR, in particular a granulate of vulcanized rubber ground into particles of minute size, for example between 0.5 and 5 mm, either used as such or encapsulated (covered) in a polyurethane resin film.

As an alternative to granular SBR, other synthetic plastic elastomer materials can be used, for example natural materials such as coco and cork, or inert materials such as sand, various grits, lapillus, expanded perlite, leca, etc.

Based on the characteristics to be obtained for the finished product, several natural or synthetic products can also be mixed together. The granular material is inserted into each tubular element 14 by a pipe through which by means of compressed air (or mechanically or by gravity) the material is forced into the tubular element in the required quantity, gradually moving the pipe rearwards as the tubular element is filled, to obtain the desired density according to its use. When filling is complete the open last side is sewn (or closed by other means) to obtain a plurality of adjacent tubular elements 14, divided only by transverse stitch seams 13 and having an elliptical cross-section, i.e. a circle elongated in the longitudinal direction of the two fabric layers 10 and 11.

In one embodiment of a resilient carpet for synthetic grass pitch foundations, a polyester fabric was used, forming the tubular elements 14 directly on the loom by weft and warp weaving, known as double tech, of weight 250 g/m ² . The tubular elements 14 were formed with a pitch of 2 cm. The tubular elements were filled with a covered SBR granulate of particle size between 0.5 and 3 mm, to obtain a carpet of weight about 6/7 kg/m ² . In this case tubular elements are obtained having a height of about 1 cm.

When used as a foundation for natural grass coverings 23, a heating carpet is used with granular leca filling which acts as a slow release water reservoir, while the heating maintains the temperature of the root substrate under control.

In the case of synthetic grass coverings, the carpet of the present invention is laid, on which the synthetic grass covering 25 is superimposed, filled with high-performance infill 24 (rubber granules or organic granules).

The carpet produced in this manner enables a final product to be obtained which conforms to the regulations of sporting federations, in particular a shock absorption greater than 60% being obtained, together with a vertical deformation between 4 an 8 mm, and optimal vertical and horizontal drainage exceeding 360 mm/h.

As the carpet is made with free granules it does not present a spring effect, hence considerably reducing return vibrations and safeguarding the player's limbs.

Moreover the toxicological values conform to the DIN 18035-7 standard.

The carpet of the present invention enables optimal drainage, both horizontal and vertical, to be obtained.

The fabric is permeable, the granulate does not comprise glues or binders, hence enables water to pass vertically through the granulate interstices and into the channels 15, to reach the underlying ground. For vertical drainage see Figure 3 and for horizontal drainage see Figure 5.

Because of its shape the carpet obtained in this manner can be stored and transported by rolling it about itself, so saving space. This also facilitates carpet installation, by unrolling it along the place of installation.

The carpet of the present invention can be fixed or coupled to other carpets or articles for other uses, or to any other element required to 5 form a playing pitch.

The material used for the carpet of the present invention can be in the form of particular fabrics known as geocomposites, which are often used as separators for the layers of a playing pitch for horizontal drainage,

i n As these elements are coupled directly to the carpet, compared with traditional systems in which they are installed separately, there is a further lowering of installation costs.

The solution described herein is usable as a foundation in football pitches, in gymnasiums, in children's play areas, etc., to eliminate the i s rigidity of concrete foundations and give a sports flooring those shock absorption and elastic rebound characteristics necessary for sports activities, and as antitrauma protection on walls, edges, poles, etc. Their acoustic and/or thermal insulating qualities enable these carpets to be advantageously used as insulants in the building and0 industrial sector.

A carpet of the present invention is easily produced by preparing the two fabric layers with a series of stitch seams as aforestated and then filling the tubular elements with the granulate, and finally closing the last side which has remained open.

5 By virtue of its composition and structure, the carpet of the present invention ensures effective water drainage by defining a water outflow zone, and excellent impact absorption characteristics.

In addition the heating makes the playing pitch also usable during winter, whether of synthetic grass or of natural grass. The heating protects it from freezing of melting snow on the playing pitch and by maintaining the temperature of the radication substrate under control for natural grass pitches.