WO2019191533A1

WO2019191533A1 - Golf practice mat with virtual divot feature

Info

Publication number: WO2019191533A1
Application number: PCT/US2019/024738
Authority: WO
Inventors: Brian Carr
Original assignee: Brian Carr
Priority date: 2018-03-30
Filing date: 2019-03-29
Publication date: 2019-10-03
Also published as: US20210038962A1

Abstract

An artificial turf for golf mimics visual and physical aspects of natural turf. The artificial turf includes a resilient, slow recovery, foam layer that temporarily deforms proximate to where the club head contacts the artificial turf during a swing, thereby allowing an uninterrupted swing arc with a descending angle of attack and forming a virtual divot cavity that mimics physical aspects of a natural turf divot. Trans-chromic synthetic grass blades on the surface of the artificial turf exhibit a temporary color change caused by contact with the club head during a swing, thereby forming a virtual divot cavity that mimics visual aspects of a natural turf divot. The slow recovery foam and trans-chromic grass blades enable analysis of the golf swing based on the virtual divot. The artificial turf may be incorporated into a practice mat.

Description

GOLF PRACTICE MAT WITH VIRTUAL DIVOT FEATURE

TECHNICAL FIELD

[001] The subject matter of the present disclosure is generally related to artificial turf and golf practice mats.

BACKGROUND

[002] Many sports are played on natural turf. Natural turf includes soil and natural grass that requires frequent maintenance. Artificial turf is also used as a playing surface in some sports. Artificial turf has synthetic fibers that mimic the appearance of natural grass. Artificial turf is more durable than natural turf and does not require sunlight, irrigation, or trimming. Consequently, artificial turf is often favored for covered stadiums and other indoor venues. However, artificial turf does not provide the same feel as natural turf as a playing surface.

[003] The game of golf is typically played outdoors on natural turf. However, artificial turf practice mats are often used for golf practice ranges, indoor golf simulators, and other situations in which natural turf would be subject to excessive wear, be difficult to grow, or would otherwise be impractical. Although a wide variety of artificial turfs are known, existing artificial turf golf practice mats do not accurately mimic all the characteristics of natural turf that are significant to the sport of golf.

SUMMARY

[004] All examples, aspects and features mentioned in this document can be combined in any technically possible way.

[005] In accordance with an aspect an apparatus comprises: an artificial turf comprising a trans-chromic material. In some implementations the trans-chromic material is part of synthetic blades of grass. In some implementations, the trans-chromic material is a thermochromic material. In some implementations the artificial turf comprises a resilient compressible layer. In some implementations the thermochromic material exhibits a base thermochromic coloration at 20 to 25 degrees Celsius. In some implementations the base thermochromic coloration is green. In some implementations the thermochromic material exhibits an activated thermochromic coloration, different than the base thermochromic coloration, above 25 degrees Celsius. In some implementations the activated thermochromic coloration is tan, brown, or red. In some implementations the synthetic blades of grass comprise a thermochromic additive that is introduced to a base material. In some implementations the base material comprises at least one of nylon, polyethylene, ethylene-vinyl acetate, and poly ethylene-vinyl acetate. In some implementations the thermochromic additive comprises at least one of spirolactones, fluorans, spiropyrans, fulgides, bisphenol A, parabens, 1,2, 3-triazole derivates, and 4-hydroxycoumarin. In some implementations the trans-chromic material comprises polymeric imitation opals. In some implementations the resilient compressible layer comprises viscoelastic foam. In some implementations the resilient compressible layer comprises polyurethane foam. In some implementations the resilient compressible layer has a thickness of from 2 to 4 cm. In some implementations the resilient compressible layer has a recovery time from a compressed state to a decompressed state of from 5 to 20 seconds.

[006] In accordance with an aspect an apparatus comprises: a golf practice mat comprising: a stance mat; and an artificial turf located in an opening in the stance mat, the artificial turf comprising synthetic blades of grass comprising a trans-chromic material. In some implementations the artificial turf comprises a resilient compressible layer. In some implementations the trans-chromic material is a thermochromic material which exhibits a base thermochromic coloration at 20 to 25 degrees Celsius and exhibits an activated thermochromic coloration, different than the base thermochromic coloration, above 25 degrees Celsius. In some implementations the resilient compressible layer comprises viscoelastic foam or polyurethane foam.

[007] In accordance with an aspect an apparatus comprises: an artificial turf comprising: synthetic blades of grass comprising a thermochromic material that exhibits a base thermochromic coloration at 20 to 25 degrees Celsius and exhibits an activated thermochromic coloration, different than the base thermochromic coloration, above 25 degrees Celsius; and a resilient compressible layer comprising at least one of viscoelastic foam and polyurethane foam. BRIEF DESCRIPTION OF THE FIGURES

[008] The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[009] Figure 1 illustrates a proper golf swing.

[0010] Figure 2 illustrates ascending and descending angles of attack.

[0011] Figure 3 is a profile view of artificial turf with natural turf-like characteristics.

[0012] Figures 4 and 5 illustrate a proper swing and virtual divot with the artificial turf of figure 3.

[0013] Figures 6A, 6B, and 6C illustrate analysis of a golf swing with the artificial turf. [0014] Figure 7 illustrates a golf practice mat that incorporates the artificial turf.

DETAILED DESCRIPTION [0015] United Stated Provisional Patent Application 62/650,319, titled GOLF PRACTICE MAT WITH VIRTUAL DIVOT FEATURE, and filed on March 30, 2018, is incorporated by reference.

[0016] To understand the characteristics of turf that are significant in the sport of golf it is helpful to understand aspects of a proper golf swing. Referring to figures 1 and 2, the game of golf involves striking a golf ball 100 with a golf club to launch the golf ball toward a hole. The golf club includes a shaft 102 with a grip at one end and a club head 104 at the other end. The golfer holds the grip and swings the club to strike the golf ball 100 with the club head 104. The swing starts with a backswing in which the club head moves in an arc away from the golf ball, and then changes to a fore-swing direction in which the club head moves in an arc toward the ball. After striking the golf ball the golfer continues to swing the club in a follow-through motion until the swing is completed. A swing in which the club head travels in an uninterrupted arc 106 with a descending angle of attack 202 relative to the golf ball is generally considered good technique. An aspect of such a swing is that the club head 104 contacts the golf ball 100 before traversing a low point 108 of the uninterrupted swing arc 106. Ideally, a central portion of the face of the club head 104, commonly referred to as the "sweet spot," is where the club contacts the golf ball 100. Contact with the sweet spot with a descending angle of attack 202 in an uninterrupted arc 106 most efficiently launches the golf ball with desired speed, loft, backspin, and distance. It should therefore be understood that characteristics of turf that enable such a swing are significant in the sport of golf.

[0017] A well-known result of a good golf swing on natural turf is creation of a divot. When the sweet spot of an iron-type golf club is properly aligned with a golf ball resting on the surface of the turf in an uninterrupted swing arc 106 with a descending angle of attack 202, the club head contacts the turf 110 shortly after contacting the golf ball 100. More specifically, the lower portion of the club head 104, including the leading edge and sole, traverses the turf 110 down to and through the low point 108. Traversal of natural turf by the club head results in a portion of natural turf known as a“divot” being partially or completely cut away from the adjacent soil. A shallow depression is created where the divot is cut away from the adjacent soil. The shallow depression may also be referred to as a divot. The divot indicates where the leading edge of the club made contact with the natural turf relative to the location of the golf ball, the plane of the swing arc, the direction of travel of the club head upon impact with the natural turf, where was the golf ball struck relative to the ideal horizontal and vertical sweet spot locations on the club head face, and how far and deep the club head travelled through the natural turf and thus the elevation of the swing arc, among other things that enable analysis of the swing. It should therefore be understood that characteristics of turf that enable formation of divots are significant in the sport of golf.

[0018] One of the shortcomings of existing artificial turf and golf practice mats is that a swing characterized by a descending angle of attack 202 in an uninterrupted arc 106 is inhibited. If the golfer attempts an uninterrupted swing arc 106 with a descending angle of attack 202 then the club head is sharply deflected by unyielding artificial turf, thereby interrupting the swing arc. Consequently, the golfer is forced to use an altered swing arc 204 to reduce the force of impact with the artificial turf. The altered arc 204 results in an ascending angle of attack 200 upon contact with the golf ball. The ascending angle of attack 200 typically results in a poor-quality golf shot. Consequently, existing artificial turf may reinforce improper swing technique.

[0019] Another shortcoming of existing artificial turf and golf practice mats is that a swing does not result in generation of a divot. As mentioned above, divots enable analysis of the golf swing. Existing artificial turf and golf practice mats typically do not generate a divot or provide a visual indication of the characteristics of the swing. Some practice mats may have surface materials that are reoriented by contact with the club head to provide some visual evidence, but those materials do not automatically recover a pre-swing orientation or create a divot.

[0020] Figures 3 through 5 illustrate an artificial turf 300 that enables a proper golf swing and generation of a virtual divot 302. The artificial turf may be implemented as a composite of multiple layers that mimic different aspects of natural turf. A first layer 304 may consist of or include synthetic grass blades 306 that form a top or outer surface of the artificial turf 300 and mimic visual aspects of natural turf. The synthetic grass blades may be oriented at pseudorandom angles and have a variety of lengths to mimic the appearance of real blades of grass. The synthetic grass blades 306 are affixed to a second layer 308 that provides a flexible backing surface and anchors the grass blades. A first distal end 310 of each synthetic grass blade is attached to the second layer 308 and a second distal end 312 extends away from the second layer. In addition to anchoring the synthetic grass blades the second layer 308 protects a third layer 314 from the club head. The third layer has properties that allow deformation to mimic physical aspects of natural turf. A fourth layer 316 provides a substrate to which the third layer 314 is affixed. The fourth layer may have characteristics and properties that help to secure the artificial turf in place on an underlying surface. Aspects of individual layers are described in greater detail below.

[0021] The first layer 304, and specifically the synthetic grass blades 306, mimic the visual appearance of natural turf and natural turf divots via selective coloration and color variation. These trans-chromic aspects may be accomplished via use of thermochromic materials. Thermochromism is a material property in which coloration of a material is dependent on the temperature of the material. The synthetic grass blades may have a selected base thermochromic coloration, e.g. green, at typical ambient temperatures such as 20 to 25 degrees Celsius, and a different activated coloration at slightly higher temperatures. Club head swings ranging from 100-160 kph may impart enough frictional energy to the synthetic grass blades to raise the surface temperature of the synthetic grass blades by 5 to 15 degrees Celsius. The thermochromic material may be selected such that the increase in temperature caused by friction from a golf swing results in a thermochromic change in coloration from the base coloration to the activated coloration. For example, the grass blades may change from the green base coloration to a tan, brown, or red activated coloration in response to a golf swing. As the grass blades cool back to ambient temperature the coloration returns to the base coloration. When implemented for a wider range of ambient temperatures, such as for outdoor use, the base coloration and activated coloration may vary as a function of the ambient temperature. In other words, the color would change although not necessarily from a single base coloration to a single activated coloration.

[0022] In some implementations a thermochromic additive is introduced to a base material to create synthetic grass blades that change color in response to the frictional energy associated with a golf swing. The base material may include nylon, polyethylene, ethylene- vinyl acetate, poly ethylene-vinyl acetate, or other suitable materials. The base material may include or be treated with UV inhibitors to protect against color fade and material breakdown from prolonged exposure to sunlight. The thermochromic additive may include a thermochromic liquid crystal or leuco dye such as spirolactones, fluorans, spiropyrans, fulgides, bisphenol A, parabens, 1,2, 3 -triazole derivates, and 4-hydroxycoumarin. The thermochromic additive may be microencapsulated. In microencapsulation, small particles or droplets of the thermochromic material are surrounded by a coating of a different material to create small capsules. The size of the microcapsules may range between 3-5 pm. Pigments may be mixed with the thermochromic microcapsules. In some implementations a thermochromic dye or paint is applied to the exterior surface of the base material. The thermochromic properties may be selected such that the synthetic grass blades temporarily change from a base color, for example green, to a highlight color, for example tan or brown, in response to contact with the golf club during a swing. For a structured color variant, the change may be a spectral shift such as green to blue and back again. The synthetic grass blades may revert to the pre-contact base color in 5 to 30 seconds as the surface of the synthetic grass blades returns to ambient temperature.

[0023] Another trans-chromic method of achieving the desired color change for the synthetic grass blades is using polymeric imitation opals. Natural opals are made up of evaporatively formed silica spheres that reflect and diffract light to form a variety of colors. A polymer opal is comprised of hard nanoparticle spheres distributed in a flexible outer shell that will similarly diffract light and generate a structural color. The size of the nanoparticle and the spacing between them will determine which wavelengths of light will be visible. The nanoparticles are crosslinked polystyrene and the outer layers are a soft polyethylene acrylate. The nanoparticles can be produced to a common size to control their visible structural color. When this synthetic grass material is deformed - stretched or compressed - the spacing of the particles changes and with it, so does the structural color. When the material elastically reforms to its original shape, the original color returns as well. As there are no pigments involved, the color properties will not fade over time.

[0024] The second (backing/interface) layer 308 may be manufactured from materials including, but not limited to, polypropylene, synthetic rubber, or elastomers such as EPDM (ethylene propylene diene monomer (M-class)) rubber with a thickness of 0.3 to 1.5 mm. The second layer may exhibit cut-resistance properties that help to maintain the integrity and durability of the artificial turf. The second layer may also be pliable and readily deform in response to the force applied through contact with the club head during a swing. In some implementations continuous filaments of spunbonded polypropylene are formed into a web that is heat bonded at filament crossover points. The result is a loose web that does not provide significant resistance to the club head during a swing. The synthetic grass blades may be attached to the second layer through a tufting or weaving process. The second layer also provides an interface between the first and third layers.

[0025] The third layer 314 may be manufactured from resilient deformable materials including, but not limited to, foam. Examples include LRPu (low-resilience polyurethane) foam and viscoelastic foams such as“Confor foam” or“memory foam.” viscoelastic foams such as Confor foam and memory foam include polyurethane and other materials that increase viscosity and density. Thickness of the third layer may be 2 to 4 cm, for example, and without limitation. Compression of the third layer proximate to contact with the club head 104 and resulting from the force applied by the club head creates a shallow depression, i.e. a virtual divot 302, that mimics the physical appearance of a divot formed in natural turf. Depth of the virtual divot varies but will typically be from 0.5 to 1.25 cm. The polyurethane foam may be selected such that recovery time from a compressed state to a decompressed state is about 5 to 20 seconds. Consequently, the virtual divot persists for an amount of time that enables analysis of the swing. The third layer may be attached to the second weave layer only along the perimeter.

[0026] The fourth layer 316 may be manufactured from a hard rubber or other material. The fourth layer may have anti-skid properties that resist sliding when horizontal forces are exerted upon it. The fourth layer may be rigid or flexible. The fourth layer may be glued or otherwise affixed to third layer. In some implementations the fourth layer is spray- applied to the third layer. The fourth layer may be bonded to the third layer at the entire contact surface.

[0027] One of the advantageous characteristics of the artificial turf 300 is deformability. Because the third layer is deformable the artificial turf exhibits an amount of resistance to a golf swing that is like natural turf. Deformability helps to enable an uninterrupted swing arc with a descending angle of attack like natural turf. Consequently, proper swing technique can be practiced and reinforced on the artificial turf.

[0028] Another advantageous characteristic of the artificial turf is resiliency. After being deformed by contact with a club head the resilient artificial turf returns to its pre-contact shape and volume, thereby automatically resetting for another swing. Another aspect of resiliency is reversible color variation. Specifically, the synthetic grass blades in the virtual divot formed by compression of the foam layer temporarily change color to mimic the exposed soil of a natural turf divot and then return to the pre-contact color over time. For example, the virtual divot may automatically revert from tan to green in about the same amount of time required for the foam layer to decompress back into its pre-contact shape and volume. The recovery period may be an amount of time that allows visual evaluation of the virtual divot without hindering a succession of swings at a frequency that is common for a practice shot session or virtual golf game. Consistent swing characteristics of any quality of successive swings may increase the recovery time of the shape and color of the artificial turf, thereby providing additional information about the golfer’s swing. Consequently, the artificial turf may be suitable for use with golf simulators and practice ranges that require golf balls to be hit from the same location in succession.

[0029] Referring to figures 6A, 6B, and 6C, another advantageous characteristic of the artificial turf 300 is that the virtual divot facilitates analysis of the golf swing. Because the virtual divot has the shape and appearance of a natural turf divot, the virtual divot may visually indicate characteristics of the swing such as where the leading edge of the club made contact with the artificial turf relative to the location of the golf ball, the plane of the swing arc, the direction of travel of the club head upon impact with the artificial turf, where was the golf ball struck relative to the ideal horizontal and vertical sweet spot locations on the club head face, and how far and deep the club head travelled through the artificial turf and thus the elevation of the swing arc, among other things. In figure 6A artificial turf 300 includes a ball placement mark 602 on which the golf ball is placed. Virtual divot 604 indicates that the club head contacted the artificial turf at location 606 before contacting the golf ball and the left-right (L-R) direction of the swing was properly aligned. The virtual divot 608 shown in figure 6B indicates that the club head contacted the artificial turf at location 610 before contacting the golf ball and the left-right direction of the swing was improperly aligned (moving from right to left). The virtual divot 612 shown in figure 6C indicates that the club head contacted the artificial turf at location 614 before contacting the golf ball and the left-right direction of the swing was properly aligned but the club head face was open (or closed, depending on whether the golfer is left-handed or right-handed), resulting in alteration of the left-right direction/plane of swing.

[0030] Figure 7 illustrates a practice mat 700 made with the artificial turf described above. The practice mat includes a small section 702 of the artificial turf, which may include markings as described above. The fourth layer material of the small section may be wrapped around the edges, e.g. attached to the edges of the second and third layers. The small section 702 is inserted into an opening in a larger stance golf mat 704. The larger stance golf mat may have different properties than the artificial turf, e.g. different firmness and density, to support the golfer. The size of the mat may be selected for portability or to fit into an opening in a floor or other surface. Together, the small section 702 of artificial turf and stance golf mat 704 may provide a realistic experience like golfing on natural turf.

[0031] Several features, aspects, embodiments and implementations have been described. Nevertheless, it will be understood that a wide variety of modifications and combinations may be made without departing from the scope of the inventive concepts described herein. Accordingly, those modifications and combinations are within the scope of the following claims.

Claims

WHAT IS CLAIMED IS:

1. An apparatus comprising: an artificial turf comprising a trans-chromic material.

2. The apparatus of claim 1 wherein the trans-chromic material is part of synthetic blades of grass.

3. The apparatus of claim 2 wherein the artificial turf comprises a resilient compressible layer.

4. The apparatus of claim 3 wherein the trans-chromic material is a thermochromic material exhibits a base thermochromic coloration at 20 to 25 degrees Celsius.

5. The apparatus of claim 4 wherein the base thermochromic coloration is green.

6. The apparatus of claim 4 wherein the thermochromic material exhibits an activated thermochromic coloration, different than the base thermochromic coloration, above 25 degrees Celsius.

7. The apparatus of claim 6 wherein the activated thermochromic coloration is tan, brown, or red.

8. The apparatus of claim 2 wherein the synthetic blades of grass comprise a

thermochromic additive that is introduced to a base material.

9. The apparatus of claim 8 wherein the base material comprises at least one of nylon, polyethylene, ethylene-vinyl acetate, and poly ethylene-vinyl acetate.

10. The apparatus of claim 9 wherein the thermochromic additive comprises at least one of spirolactones, fluorans, spiropyrans, fulgides, bisphenol A, parabens, 1,2, 3-triazole derivates, and 4-hydroxycoumarin.

11. The apparatus of claim 1 wherein the trans-chromic material comprises polymeric imitation opals.

12. The apparatus of claim 3 wherein the resilient compressible layer comprises viscoelastic foam.

13. The apparatus of claim 3 wherein the resilient compressible layer comprises polyurethane foam.

14. The apparatus of claim 3 wherein the resilient compressible layer has a thickness of from 2 to 4 cm.

15. The apparatus of claim 3 wherein the resilient compressible layer has a recovery time from a compressed state to a decompressed state of from 5 to 20 seconds.

16. An apparatus comprising: a golf practice mat comprising: a stance mat; and an artificial turf located in an opening in the stance mat, the artificial turf comprising synthetic blades of grass comprising a trans-chromic material.

17. The apparatus of claim 16 wherein the artificial turf comprises a resilient

compressible layer.

18. The apparatus of claim 17 wherein the thermochromic material exhibits a base thermochromic coloration at 20 to 25 degrees Celsius and exhibits an activated thermochromic coloration, different than the base thermochromic coloration, above 25 degrees Celsius.

19. The apparatus of claim 18 wherein the resilient compressible layer comprises viscoelastic foam or polyurethane foam.

20. An apparatus comprising: an artificial turf comprising: synthetic blades of grass comprising a thermochromic material that exhibits a base thermochromic coloration at 20 to 25 degrees Celsius and exhibits an activated thermochromic coloration, different than the base thermochromic coloration, above 25 degrees Celsius; and a resilient compressible layer comprising at least one of viscoelastic foam and polyurethane foam.