Classifications

• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
  • E01C13/00—Pavings or foundations specially adapted for playgrounds or sports grounds; Drainage, irrigation or heating of sports grounds
  • E01C13/08—Surfaces simulating grass ; Grass-grown sports grounds

Definitions

• This invention relates to an improved synthetic turf surface for grass-type game playing fields.
• Synthetic turf game playing surfaces typically are formed of carpets having upright piles or strands that are fastened to a base or backing sheet.
• the strands may be formed of thin, flat, narrow strips of suitable plastic material which may be gathered into tufts that are fastened to the base sheet.
• the base sheet is formed of a woven cloth, made of a suitable plastic fabric, with a resilient coating or binder applied to the base sheet for anchoring the strands thereto.
• the detailed construction of such pile carpets varied considerably. However, in general, they are made of a weather resistant or outdoor type of construction.
• Such carpets are usually laid upon a prepared, flat ground surface to form a game playing field which is intended to simulate a natural grass playing field surface.
• a resilient underpad is placed beneath the carpet and upon the firm ground support surface to provide a shock absorbing effect.
• a layer of sand or other particulate material is placed upon the upper surface of the carpet base sheet and around the strands.
• Patent No. 3,597,297 issued August 3, 1971 to Theodore Buchholz et al., which discloses a polyurethane underpad having voids; and U.S. Patent No. 4,505,960 issued March 19, 1985 to James W. Leffingwell, which discloses shock absorbing pads made of foamed polyvinyl chloride, polyethylene, polyurethane, polypropylene, etc.
• the present invention relates to a particular plastic underpad surface combined with an artificial grass forming carpet which very closely simulates a natural grass field which is particularly close in feel and performance to the natural grass portions of a typical golf course, as well as being very similar to other natural grass surface game playing fields.
• This invention contemplates combining with a synthetic grass carpet a particular resilient polypropylene molded underpad which, together with the synthetic grass carpet, produces an effect which is strikingly similar to a natural grass playing surface formed particularly for golf courses.
• this invention contemplates utilizing expanded beads of polypropylene of a density of approximately between about 1.3 to 2.8 pounds per cubic foot molded into a thick sheet or pad of open cell structure with a density of between about 1.5 to 3 pounds per cubic foot.
• the combined turf carpet and supporting underpad effect may be enhanced by treating the free ends of the synthetic grass blades with a sandblast which splits or shreds the blade ends into fine slivers which intertwine and entangle with each other to form a dense mat upper surface upon the carpet.
• An object of this invention is to provide an artificial turf with a particular resilient underpad formed of open cell, expanded beads polypropylene plastic which produces, as part of the turf surface, an effect which very closely simulates a natural grass playing field.
• FIG. 1 is a schematic, fragmentary, cross-sectional end view of a synthetic turf pile carpet.
• FIG. 2 is a schematic view similar to FIG. 1 , showing the carpet positioned upon a resilient, molded open cell, expanded bead polypropylene underpad.
• FIG. 3 is a view, similar to FIG. 2, illustrating the step of sandblasting the upper end portions of the blade forming strands of the carpet.
• FIG. 4 schematically illustrates the artificial turf surface with the dense mat formed by the shredded slivers and with a layer of sand deposited by the sandblasting step upon the upper surface of the carpet base sheet.
• FIG. 5 schematically illustrates a further, optional, step of spraying the carpet with a water wash for further severing the slivers on a strand while additionally entangling or intertwining adjacent slivers to form the dense mat surface and, also, a rotary brush treating the upper surface of the mat.
• FIG. 6 schematically illustrates a single U-shaped strand whose free upper ends have been shredded into fine slivers by the sandblasting treatment.
• FIG. 7 schematically illustrates a fragmentary portion of a golf course where the golfer may use a Tee.
• FIG. 8 is an enlarged, fragmentary, schematic, cross-sectional view showing a Tee inserted in a slot provided in artificial turf which has a mat formed on its upper surface.
• FIG. 9 is a view similar to FIG. 8 showing a Tee inserted in a slot formed in turf which is not formed with upper end slivers and a matted surface.
• FIG. 1 schematically illustrates a fragment of a synthetic turf pile carpet.
• the carpet has numerous, closely spaced, tufts 11 which are formed of U-shaped, flat, narrow bent strips or strands 12 that form artificial grass blades.
• the turfs are fastened upon a base or backing sheet 14.
• This sheet may be made of a woven cloth or the like fabric material formed of stable, weather resistant, plastic such as polypropylene or nylon fibers or the like.
• the specific cloth must be flexible but, otherwise, may vary as to its composition.
• the tufts are inserted around or through the fibers forming the base sheet.
• a suitable binder layer 16 may be applied to bind the turfs and base sheet together.
• the binder may be formed of a polyurethane adhesive material or some other suitable, outdoor usable adhesive which remains resilient or flexible.
• the carpet is placed upon a resilient cushion underpad 18.
• This underpad is formed of a relatively thick, molded sheet or pad of resilient, open cell, expanded bead polypropylene.
• the sheet may be approximately between about 1/2 inch to 2 inches in thickness, with a preferred density of approximately 2.36 pounds per cubic foot. The density may be varied within the range of between about 1.5 to 3 pounds per cubic foot.
• the thickness of the pad may also be varied from about 1/4 inch thickness to as much as up to 12 inches thick.
• the upper portions of the strands or blades are sprayed with a blast of sand 20 or similar sandlike particulate material from a pressurized nozzle 21.
• This blast of sand shreds each of the strand upper end portions into numerous slivers 23 (see FIG. 6).
• the slivers extend laterally and intertwine and entangle together to form a dense mat 24.
• the spray nozzle 21 may be moved back and forth from one side to the other in a scanner-like movement across the upper end portions of the blades formed by the strands.
• the exact pressure of the sand blast spray may be varied. However, a preferred blast pressure is in the range of 100 to 120 pounds per square inch.
• the blast may use silica sand of a size range of between about 16 to 40 mesh and, preferably, in the range of between about 20 to 24 mesh or even more preferably in the approximate area of 24 mesh.
• the sandblasting is conducted at a speed of movement and for a length of time which is sufficient to shred the strand end portions into finely divided slivers. For example, the upper, about one-fifth portions of the blades may be shredded into fine slivers that remain attached to their respective blades.
• the force of the sand blast depending upon how long, that is, how slowly the blast is moved across the surface of the carpet, not only shreds the blades, but also forces the sprayed sand downwardly between the strands to deposit sand upon the surface of the base sheet of the carpet.
• the sand layer 25 formed thereby may be kept upon the base sheet of the carpet where it is maintained in position by the dense intertwined or entangled sliver mat formed on the upper ends of the blades.
• a blade height of approximately 5/8 of an inch above the surface of the base sheet, which is useful for a golf green surface may have its upper 20 to 33 percent of its length shredded into fine slivers.
• strands which are approximately 1/16 of an inch, i.e. about 0.07 inches, wide and about 0.002 inches thick, so that they are approximately rectangular in cross-section. They are bent in half, to form two blades, and are gathered into tufts of about 9 to 11 strands. These form about 18 to 22 blades per tuft.
• the upper about 20 percent portions of each blade may be severed into about four slivers.
• each tuft may have as many as about 70 to 80 slivers whose lower ends remain attached to the blade body and whose upper ends extend off into transverse directions to entangle with the slivers of adjacent strands.
• the slivers are about 0.02 inches in width and about 0.075 to 0.125 inches long.
• the carpet may be further treated with a high pressure water spray 27 applied by a pressurized nozzle 28.
• the water spray which, for example, could be at a roughly 100 to 150 pounds per square inch nozzle pressure, acts like a wash which further separates adjacent slivers that were shredded, but not fully separated from each other on the same strand, and simultaneously further twists, bends and entangles the slivers of one strand with slivers on its adjacent strand to further density the mat formed by the intertwined slivers. This forms a denser and more uniform mat surface.
• the mat surface may be further treated by brushing it with, for example, a rotary brush 29 applied upon the mat surface to make the mat surface more uniform.
• the water jet and the brushing may be performed successively or at the same time as schematically illustrated in FIG. 5.
• the force of the sandblasting is sufficiently absorbed through the resilient cushioning pad beneath the carpet to prevent the strands from becoming crushed or permanently deformed or compacted by such force. That is, the strands remain or return to their upright positions after their upper ends are sand blasted. The upright positions are maintained, in part, by the deposited sand layer 25. Similarly, the strands and the mat 24 hold the sand layer 25 in place.
• the sand layer filling may be kept in place and the matted carpet may be rolled and transported to the site where it is to be spread and used with the sand layer.
• the treated carpet may be unrolled and installed at the game surface site when desired and the sand layer will remain in place and additional sand at the use site for a sand filling may not be needed.
• pile carpet construction may be varied.
• an example of a useful carpet for a golf green comprises synthetic grass of approximately 7,600 deniers, an approximate density of 42 ounces per square yard, and a fiber height of approximately 5/8 inch combined with an underpad of 1/2 inch to 2 inches in thickness.
• an example of a fairway portion of a golf course may be in the range of approximately 7,600 deniers synthetic grass, an approximate density of 42 to 55 ounces per square yard, with a fiber height of about 5/8 to 2 inches with an underpad of at least about one inch thick.
• Still another example of the synthetic grass would be a weaving standard in the range of 3,600 to 10,000 deniers, with 13 to 22 stitches per 3 inches, 3/16 gage and a density of about 34 to 65 ounces per square yard of material.
• the raw beaded polypropylene material is commercially available and can be molded into underpads of the desired density.
• expanded polypropylene beads are available from BASF under the trade name of NEOPOLEN P, which is a trademark of BASF. This material is available at densities of 1.3, 1.9 and 2.8 pounds per cubic foot and is referenced by BASF by its trademark EPERAN PP, types PP45, PP30 and LBS 20.
• the resulting pad produced in the desired thickness, can be made in a density ranging from 1.5 to 3 pounds per cubic foot.
• the molded slab or sheet will have an open cell construction.
• the specific density selected may be varied for specific sport activities. For example, a density that has been found satisfactory for a golf green is in the range of approximately 2.36 pounds per cubic foot.
• the particular technique useful for the sandblast treatment involves sandblasting under pressure using commercially available sandblast equipment.
• a pressure in the range of 100 to 120 pounds per square inch is preferred but the pressure may be varied somewhat, such as a low of about 80 pounds per square inch.
• the angle of the projected spray may vary but a preferred angle, which appears to be effective in a minimum of time, is an angle of about 70 to 80 degrees relative to the plane of the carpet.
• the distance of the nozzle from the strands may vary, with the equipment operator selecting the optimum distance by visually observing the shredding action of the spray.
• the distance may be in the range of about 4 to 5 feet, depending upon the speed of movement of the nozzle across the carpet.
• the resulting synthetic turf is particularly useful for golf courses, such as the green portions, approach portions, Tee-off portions and fairway.
• the turf surface also may be used for tennis courts, football or soccer as well as for other sports which utilize grass surfaces. Examples of these are grass hockey, croquet, grass bowling, children playground, baseball, and the like.
• the surface of the artificial turf produced by the method herein closely simulates the feel and action or rebound produced by a natural grass surfaced playing field.
• the completed, matted surface very closely simulates the natural grass surfaces required for golf courses and the similar playing fields.
• This turf may also be useful upon a rooftop or patio or deck surface where the turf will provide an insulated, waterproof covering.
• the turf may be used on golf courses in Tee-off places, that is, at locations where the golfer uses a Tee to support the ball for a drive.
• a number of slits 30 may be made in the turf carpet base sheet and underpad to receive a manually inserted standard Tee.
• the slits 30 may be of a size to closely receive a Tee 31.
• a colored mark 32 may be applied, as by a suitable ink or paint mark, on the surface of the turf.
• FIG. 7 shows the turf with the sliver forming mat
• FIG. 8 shows the turf mold without the surface mat. In either case the slots can be used to receive the golfer's Tee.
• This invention may be further developed within the scope of the following claims. Accordingly, it is desired that the foregoing description be read as being merely illustrative of an operative embodiment of this invention and not in a strictly limiting sense.

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• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Road Paving Structures (AREA)
• Prostheses (AREA)
• Dental Preparations (AREA)
• Materials For Medical Uses (AREA)
• Tires In General (AREA)
• Pyrane Compounds (AREA)
• Vehicle Interior And Exterior Ornaments, Soundproofing, And Insulation (AREA)
• Laminated Bodies (AREA)
• Woven Fabrics (AREA)
• Pens And Brushes (AREA)
• Level Indicators Using A Float (AREA)
• Road Repair (AREA)

Priority Applications (1)

Applications Claiming Priority (3)

Publications (2)

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Family Applications (1)

Country Status (17)

Families Citing this family (30)

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• 1997
  • 1997-06-09 CA CA002206295A patent/CA2206295A1/fr not_active Abandoned
• 1998
  • 1998-06-09 JP JP50119199A patent/JP3739055B2/ja not_active Expired - Fee Related
  • 1998-06-09 AT AT98925367T patent/ATE216448T1/de active
  • 1998-06-09 RU RU2000100343/03A patent/RU2188888C2/ru not_active IP Right Cessation
  • 1998-06-09 EP EP98925367A patent/EP0988423B1/fr not_active Expired - Lifetime
  • 1998-06-09 PT PT98925367T patent/PT988423E/pt unknown
  • 1998-06-09 NZ NZ502184A patent/NZ502184A/en unknown
  • 1998-06-09 WO PCT/CA1998/000559 patent/WO1998056993A1/fr active IP Right Grant
  • 1998-06-09 ID IDW20000047A patent/ID23397A/id unknown
  • 1998-06-09 DE DE69804960T patent/DE69804960T2/de not_active Expired - Lifetime
  • 1998-06-09 AU AU77548/98A patent/AU742420B2/en not_active Ceased
  • 1998-06-09 CN CNB988071002A patent/CN1184381C/zh not_active Expired - Fee Related
  • 1998-06-09 DK DK98925367T patent/DK0988423T3/da active
  • 1998-06-09 ES ES98925367T patent/ES2178218T3/es not_active Expired - Lifetime
  • 1998-06-09 BR BR9810428-4A patent/BR9810428A/pt not_active IP Right Cessation
• 1999
  • 1999-12-08 NO NO19996026A patent/NO316520B1/no not_active IP Right Cessation
• 2001
  • 2001-02-21 HK HK01101234A patent/HK1030248A1/xx not_active IP Right Cessation

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