Patent EA-004454-B1 (EA)
Title: Synthetic grass with resilient granular top surface layer
Inventor: PREVOST JEAN
IPC: E01C13/08
Filed: 2001-06-21
Abstract: 1. A synthetic grass assembly for installation on a supporting substrate, the assembly comprising : a pile fabric with a flexible sheet backing and a plurality of upstanding synthetic ribbons of a selected length, the ribbons extending upwardly from an upper surface of the backing; an infill layer of particulate material disposed interstitially between the upstanding ribbons upon the upper surface of the backing and of a depth less than the length of the ribbons, the particulate material selected from the group consisting of hard and resilient granules; the infill layer comprises: a bottom course of intermixed hard and resilient granules of substantially identical size distribution, disposed upon the top surface of the backing; and a top course substantially exclusively of resilient granules disposed upon the bottom course, an upper portion of the synthetic ribbons extending upwardly from a top surface of the top course. 2. A synthetic grass assembly according to claim 1 wherein the resilient granules in the top course are larger than the resilient granules in the bottom course. 3 A synthetic grass assembly according to claim 1 or 2 wherein the hard granules and resilient granules in the bottom course are of shape defined in the range of 0.5 to 0.99 on the Krumbein scale of sphericity. 4. A synthetic grass assembly according to claim 3 wherein the hard granules and resilient granules in the bottom course are in the range of 0.6 to 0.9 Krumbein scale. 5. A synthetic grass assembly according to any one of claims 1 to 4 wherein the resilient granules are selected from the group consisting of: cryogenically ground rubber; rubber; cork; polymer beads; synthetic polymer foam; styrene; perlite, neoprene, and EPDM rubber. 6. A synthetic grass assembly according to any one of claims 1 to 5 wherein the hard granules are selected from the group consisting of: sand; hard aggregate; silica sand; gravel; slag; granulated plastic; and polymer beads. 7. A synthetic grass assembly according to any one of claims1 to 6 wherein the particulate material of the infill comprises granules of size ranging between 0.5 inches maximum nominal diameter and 50 screen mesh standard. 8. A synthetic grass assembly according to claim 7 wherein the particle sizes of 80% by weight of hard granules and resilient granules in the bottom course are distributed in a range spanning a numerical difference of 40 in screen mesh standard. 9. A synthetic grass assembly according to claim 8 wherein the particle sizes of 80% by weight of hard granules and resilient granules in the bottom course are distributed in a range spanning a numerical difference of 20 in screen mesh standard. 10. A synthetic grass assembly for installation on a supporting substrate, the assembly comprising: a pile fabric with a flexible sheet backing and a plurality of upstanding synthetic ribbons of a selected length, the ribbons extending upwardly from an upper surface of the backing; an infill layer of particulate material disposed interstitially between the upstanding ribbons upon the upper surface of the backing and of a depth less than the length of the ribbons, the particulate material selected from the group consisting of hard and resilient granules, wherein the synthetic ribbons: are longitudinally intermittently slit in a predetermined pattern of slits; an upper portion of the ribbons extending above the infill layer and longitudinally split into individual free-standing strands of a selected width to represent grass blades; and a lower portion of the ribbons having said slits extended open forming laterally linked strands disposed in a lattice structure enmeshing the surrounding particulate infill material. 11. A synthetic grass assembly according to claim 1 wherein the synthetic ribbons are disposed in rows spaced apart a selected minimum distance. 12. A synthetic grass assembly according to claim 11 wherein the maximum distance between rows of synthetic ribbons tufted in the fabric backing is 2.25 inches. 13. A synthetic grass assembly according to claim 12 wherein the maximum distance between rows of synthetic ribbons tufted in the fabric backing is 1.0 inch. 14. A synthetic grass assembly according to claim 13 wherein the maximum distance between rows of synthetic ribbons tufted in the fabric backing is 0.625 inches. 15. A synthetic grass assembly according to claim 1 wherein depth of the infill layer is in the range between 90% to 40% of the length of synthetic ribbons. 16. A synthetic grass assembly according to claim 15 wherein depth of the infill layer is in the range between 85% to 55% of the length of synthetic ribbons. 17. A synthetic grass assembly according to claim 16 wherein depth of the infill layer is in the range between 80% to 70% of the length of synthetic ribbons. 18. A synthetic grass assembly according to claim 1 wherein the synthetic ribbons are fibers selected from the group consisting of: polypropylene; polyethylene; nylon; and plastic. 19. A synthetic grass assembly according to claim 1 wherein the upper portion of the synthetic ribbons are fibrillated into individual strands of a width in the range between 1.0 to 15.0 mm. 20. A synthetic grass assembly according to claim 1 wherein the synthetic ribbons are of a thickness in the range between 45 to 200 microns. 21. A synthetic grass assembly for installation on a supporting substrate, the assembly comprising: a pile fabric with a flexible sheet backing and a plurality of upstanding synthetic ribbons of a selected length, the ribbons extending upwardly from an upper surface of the backing; the backing and pile fabric being suitable for receiving an infill of particulate material interstices to a fraction of the selected length of the ribbons, wherein the synthetic ribbons: are longitudinally intermittently slit in a predetermined pattern of slits; an upper portion of the ribbons longitudinally split into individual free-standing strands of a selected width to represent grass blades; and a lower portion of the ribbons having said slits extended open forming laterally linked strands disposed in a lattice structure adapted to enmesh a surrounding infill particulate material.