Artificial turf with granule retaining fibers

Abstract

An artificial turf is provided that resists migration of rubber infill into the space above the turf. Artificial grass is attached to and extends upward from a backing material, which may be one or more layers. The artificial grass includes groups of at least two different kinds of fiber sewn through a common path in the backing material. One of the kinds of fibers is an artificial grass blade shaped so as to appear like a blade of grass. The other kind of fiber in each group is pre-stressed/crimped so that the relaxed shape of the fiber is nonlinear, resembling a curlicued or articulated form having lateral excursions. The lateral excursions cause portions of one such pre-stressed fiber to overlap and interfere with another, forming a mesh. The height of the pre-stressed fibers in their relaxed state in the turf is less than the height of the relatively unstressed fiber(s). Resilient granules are embedded in the mesh, and are captivated by the interfering pre-stressed fibers. In one embodiment, the pre-stressed fiber is constructed of nylon material, and the relatively unstressed artificial grass blade of polyethylene.

1 . An artificial turf comprising:
 a backing; and   a plurality of resilient first fibers pre-stressed so as to have a non-linear shape with lateral excursions when not under tension, and a plurality of second fibers shaped to resemble grass blades, wherein at least one first and at least one second fiber are sewn through common openings in said backing, and extend upward from said backing to a cut end.   
     
     
         2 . A turf as recited in  claim 1  wherein said first fibers extend upward from said backing a first height and said second fibers extend upward from said backing a second height greater than said first height. 
     
     
         3 . A turf as recited in  claim 2  further comprising particles including resilient granules positioned in said turf. 
     
     
         4 . A turf as recited in  claim 2  wherein said second height is in the range of 2 to 3 inches, and said first height is in the range of 1¾ to 2¾ inches. 
     
     
         5 . A turf as recited in  claim 3  wherein a layer of said granules extends upward from said backing a height less than said first height. 
     
     
         6 . A turf as recited in  claim 5  wherein said lateral excursions of said first fiber provide resistance to motion of said particles. 
     
     
         7 . A turf as recited in  claim 6  wherein groups of said first fibers are spaced apart such that lateral excursions of first fibers of one group overlap lateral excursions of first fibers of an adjacent group thereby providing a mesh for resisting movement of said particles. 
     
     
         8 . A turf as recited in  claim 7  wherein said groups of first fibers are in rows separated by distances in the range of ⅜″ to ¾″. 
     
     
         9 . A turf as recited in  claim 1  wherein said first fibers are made from nylon. 
     
     
         10 . A turf as recited in  claim 1  wherein said second fibers are made from polyethylene. 
     
     
         11 . A method of manufacture of artificial turf comprising:
 sewing into a backing a plurality of resilient first fibers pre-stressed so as to have a non-linear shape with lateral excursions when not under tension, and a plurality of second fibers shaped to resemble grass blades, wherein at least one first and at least one second fiber are sewn through common openings in said backing, and extend upward from said backing to a cut end.   
     
     
         12 . A method as recited in  claim 11  wherein said first fibers extend upward from said backing a first height and said second fibers extend upward from said backing a second height greater than said first height. 
     
     
         13 . A method as recited in  claim 12  further comprising
 inserting particles including resilient granules in said turf. 
 
     
     
         14 . A method as recited in  claim 12  wherein said second height is in the range of 2 to 3 inches, and said first height is in the range of 1¾ to 2¾ inches. 
     
     
         15 . A method as recited in  claim 13  wherein a layer of said granules extends upward from said backing a height less than said first height. 
     
     
         16 . A method as recited in  claim 15  wherein said lateral excursions of said first fiber provide resistance to motion of said particles. 
     
     
         17 . A method as recited in  claim 16  wherein groups of said first fibers are spaced apart such that lateral excursions of first fibers of one group overlap lateral excursions of first fibers of an adjacent group thereby providing a mesh for resisting movement of said particles. 
     
     
         18 . A method as recited in  claim 17  wherein said groups of first fibers are in rows separated by distances in the range of ⅜″ to ¾″. 
     
     
         19 . A method as recited in  claim 11  wherein said first fiber is made from nylon. 
     
     
         20 . A method as recited in  claim 11  wherein said second fiber is made from polyethylene.