AU598656B2 - Sports surface - Google Patents

Description

d -T AUSRALT& 598656 Form PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE Short Title: Int. Cl: Application Number: Lodged: This document cot he lSectiondme ts ade und e r ctin 49 and is correct for printing.

t Complete Specification-Lodged: Accepted: Lapsed: Published: Priority: Pelated Art: TO BE COMPLETED BY APPLICANT Name of Applicant: a Address of Applicant: S Address of Applicant: SUPER-GRASSE PTY. LIMITED 65-75 Captain Cook Drive, Caringbah, N.S.W.

Actual Inventor: Address for Service: Complete Specification for the HALFORD MAXWELL, Patent Trade Mark Attorneys, 49 51 York Street, SYDNEY. 2000.

invention entitled: 'SPORTS SURFACE'.

The following statement is a full description of this invention, including the best method of performing it known to us -2- This invention relates to artificial surfaces particularly although not exclusively adapted to the playing of sports, such surfaces comprising a tufted pile and a supporting backing.

Such surfaces are now in widespread use in sports such as tennis, bowls, football, hockey, baseball and indoor cricket and are finding increasing applications in other sports, for example equestrian sports.

o oo i 0 0 ;00 a00* 1 p An object of the present invention is _o provide a surface which, while having general application in such sporting areas and in non-sport surfaces, is particularly well adapted for games such as tennis, where the manner of bounce and rebound of a ball from the surface is of great concern, and in lawn bowls where the influence of the surface on the rolling trajectory of the bowl is crucial j to its performance.

Synthetic turf surfaces employed on tennis courts are typically formed by a tufted pile of a material such as polypropylene, suitably in the form of a flat fibrillated yarn which is tufted into a backing material, which may for example be an ultra-violet stabilised woven polypropylene fabric. The~pile height and denier is chosen to suit the particular application, and upon installation the pile is normally filled with a granular material such as sand.

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-3- A disadvantage of such artificial surfaces when employed in games such as tennis, baseball and cricket, is the anisotropic bounce characteristic of the surface, whereby the trajectory of a ball as it bounces from the surface will depend on the direction of travel. A ball hit "against the grain" will bounce higher and more slowly than a ball hit "with the grain." Studies of such materials have shown that this characteristic results from a "lean" which is imparted to the pile as a result of the tufting process, and as result of the twist which is applied to the fabric during manufacture of the surface.

5 This problem is not, it has been found, overcome by careful filling of the pile, and the present invention seeks to overcome the problem in a new way.

By the use of the present invention, the surface is rendered isotropic in its bounce characteristics to a degree which enables, in a preferred form of the invention, an appearance of "grain" or mowing lines to be imparted to the material for aesthetic purposes, while retaining its non-directional characteristics.

As is well known in the manufacture of fabrics such as the tufted fabrics in question, a twist is imparted to the yarn prior to tufting, normally by winding the flat, fibrillated yarn onto cones, where it is left for long enough to be set in a twist, or helical configuration.

Depending on the direction in which the yarn is wound, the twist will be in one or the other of two directions, these i4 -4being distinguished as or twists.

The invention is based on the discovery that if alternating rows (or groups of rows) of the pile are formed from yarn having opposite twist, so that for example every second row has an twist while the intervening rows have a twist, the tendency for the pile to lean in a particular direction is substantially reduced.

ooe O 0 °The accompanying drawings illustrate the manner in which *0o.

°0 0 0 this is carried out.

0*00 0 Fig. 1 shows a fragmentary lateral cross-section of a finished synthetic turf product incorporating the invention. This comprises a backing 10 of polypropylene

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fabric, into which are tufted rows 11, 12 of pile comprising a fibrillated polypropylene yarn. Each of the rows 11 is formed from yarn having an twist, and each 20 row 12 from yarn having a twist.

Fig. 2 shows schematically, in plan view, layout of the rows 11 and 12 in a fragment of the product.

The synthetic turf product is finished by a latex or other suitable binding layer 13 applied over the loops of the pile.

As will be seen particularly in Fig. 2, the rows of the i pile aT, spaced in pairs in the longitudinal direction of the material, to give the directional appearance referred to above, reproducing the effect of mowed grass, but without producing disturbing directionality in bounce or roll, due to the alternation of the twist in the rows.

Whilst it is preferred that adjacent rows comprise yarn of opposite twist, it may be found acceptable to alternate the twist in groups of rows, for example by having a pair P1' 10 of adjacent rows of twist, the next pair of twist, and so on.

These and other variations within the scope of the t4

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invention will be apparent to the skilled reader, and are included within the scope of this disclosure.

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Claims (4)

1. A synthetic turf material comprising a tufted pile consisting of parallel rows of tufts, characterized in that adjacent rows are formed from yarn having respectively an twist and a twist whereby to impart to said turf material a substantially isotropic bounce characteristic.

2. A synthetic turf material comprising a tufted pile consisting of parallel rows of tufts, characterized in that adjacent groups of rows across a ball impact width are formed from yarn having respectively an "S" twist and a twist whereby to impart to said turf material a substantially isotropic bounce characteristic.

00003. A synthetic turf material according to claim 1 or 2 further comprising a backing fabric into which said tufts are looped, a binding layer being applied over the loops of said pile.

4. A synthetic turf material substantially as described herein with reference to the accompanying drawings. DATED this 2nd day of April, 1990. SUPER-GRASSE PTY. LIMITED Patent Attorneys for the Applicant: 000 HALFORD CO.