Infilled artificial turf surfaces have become increasingly popular in recent years, particularly as a playing surface for athletic fields used for football, soccer, lacrosse, field hockey, etc. Such infilled artificial turfs are disclosed in, for instance, U.S. Pat. No. 6,551,689, which is expressly incorporated by reference herein, in its entirety.
Generally, an infilled artificial turf comprises a subsurface drainage system, with various drainage components located within a compacted base. The compacted base usually includes a soil sub-base, a lower layer of stone or gravel, and a layer of finer gravel located above the stone. This substructure provides a level and compact base, or foundation, to support the athletic field located thereabove.
The actual artificial turf components comprise a horizontally oriented backing often called a “primary,” and grass-like fibers extending upwardly from the primary, with a particulate infill material located within and among the grass-like fibers to support the fibers and help to maintain a grass-like playing surface. Infill materials may comprise sand particles, coated sand, resilient particles, or a mixture of these various types of particles. One commonly used resilient particulate includes ambiently or cryogenically ground crumb rubber, which is produced from used automotive or truck tires. With a sand/rubber mixture, the sand provides ballast and weight for holding down the turf component on the base, and also provides a desired degree of firmness, while the rubber particles provide a desired degree of resiliency and shock absorption.
Despite the relatively wide variety of possible infill materials, for practical and economic reasons, most infilled artificial turf athletic fields have used an infill comprising a mixture of sand and crumb rubber. For these types of fields, the total weight of the infill on a particular field, such as a normal U.S. sized football, is in the range of about 250-750 thousand pounds. This presents an enormous amount of infill for the owner to dispose of when replacing the field, and such disposal presents correspondingly significant logistics and practical problems. More particularly, because these infills include crumb rubber, and many jurisdictions now wish to discontinue any further use of crumb rubber as an infill, due to environmental concerns, there are limits on what the owner or the contractor is able to do with an already-used infill from a worn-out infilled artificial turf.
For a significant number of institutions which have installed and used this type of infilled artificial turf field, including professional teams, colleges and universities, and high schools, the first generation, or originally installed, infilled artificial turf has now worn down and/or needs to be replaced, or has outlasted its warranty. Because of the continuing popularity of infilled artificial turf fields, the owners of such worn down artificial turfs often choose to replace the existing and worn infilled artificial turf field with a new infilled artificial turf field. As a result of this situation, these athletic field owners have a need to optimize the efficiency and the cost-effectiveness in removing an existing in-place infilled artificial turf and installing a new infilled artificial turf. The present applicant has developed a line of equipment that helps such owners in meeting that need. This equipment is shown and described in PCT Patent Application No. PCT/US2014/025514 (the “PCT '514 application”), entitled “Apparatus For Infill Extraction And Collection,” which is expressly incorporated by reference herein, in its entirety. This equipment is identified via the trade name Turf Reclamation Services, as shown at www.recyclingartificialturf.com.
More particularly, this equipment includes an infill extractor/collector device which has achieved significant success in removing an existing infilled artificial turf field, and in extracting and reclaiming the already-used infill from the removed turf. As taught in the PCT '514 application, the extracted and reclaimed infill can be reused as the infill for the next field located at the same site, with or without on-site cleaning prior to re-use. Alternatively, it can be sent offsite for reuse elsewhere, with or without cleaning before pre-use. As another alternative, although not preferred, the already-used infill may simply be discarded in a landfill.
Regardless, because of the significant volume and weight of the extracted and reclaimed infill, i.e., as noted above, over 250,000 pounds, it is important for the field owner to make a determination as to what to do with the existing infill before the existing turf is removed. Among other reasons, it is difficult to dispose of such a large volume of extracted infill, particularly if the infill includes crumb rubber particles from vehicle tires. In some jurisdictions disposal in a landfill is not an acceptable or available option, for a number of reasons. In other situations the field owner may wish to reuse the extracted infill in the new field. Under this scenario it is best to first clean the already-used infill. Although such cleaning is technically possible, it can be prohibitively expensive. Thus, such cleaning of the reclaimed infill prior to reuse often does not occur. In still other situations the field owner may choose to use a different type of infill with the new field, rather than the originally used sand/rubber mixture.
For all of these reasons there remains a need to extract and collect the particulate infill from an already-used infilled artificial turf, and to identify a proper way to dispose of or repurpose the already-used infill that has been extracted and collected. In some cases, the already-used infill may represent the best particulate infill for reuse in the new field, at the same site. In other cases, particularly if the field owner wishes to install a new infilled artificial turf with a different type of infill, perhaps a newer type of infill, then the need to bag and transport the extracted infill to another site, whether for reuse or subsequent disposal, may represent an unreasonable expense.
As noted above, the synthetic backing of an infilled artificial turf resides on a compacted base. The top surface of the base often comprises a gravel particulate referred to as “fines.” Typically, for practical reasons the base also comprises materials that are relatively convenient to obtain in the particular geographical area where the field is located. In many parts of the continental United States limestone is prevalent and/or readily accessible. This often means that the “fines” within the particulate at the top of the base will include limestone.
Unfortunately, limestone fines have a tendency to consolidate and compact over time, and in some situations become cement-like in nature. This can create an impenetratable crust on the topmost surface of the base, of about 2-3 inches in depth. This crust is not necessarily difficult to break up, when it is time to install the new field. However, the problem is that simply breaking up the crust serves as merely a temporary fix. That is, shortly thereafter the topmost surface of the base may again eventually reach the same condition, namely, that of an impenetratable crust which can inhibit the normal water drainage of the field.
With an in-place field, when this type of crusting occurs at the top of the compacted base, and the drainage becomes impaired, the only way to fix the problem is to cut through the artificial turf residing thereabove. In other words, the synthetic turf must be cut to allow access to the problematic surface located therebelow. Obviously, this requires downtime for the field itself, and it also causes inconvenience and costs associated with repairs. Moreover, because the likelihood of recurrence could be relatively high, the overall burden associated with this downtime and repair work can become significant.
It is an object of the present invention to decrease the costs associated with installing a new athletic field at the site of an already existing infilled artificial turf field.
It is another object of the present invention to enable a field owner to identify and use the best possible infill material for a newly installed infilled artificial turf, with minimal cost considerations related to the disposal of the already-used infill extracted from a preexisting infilled artificial turf.
It is still another object of the present invention to improve the drainage characteristics of the base used for a newly installed infilled artificial turf, particularly at field sites of a preexisting infilled artificial turf.
It is yet another object of the present invention to achieve these objects while also accommodating the needs of field owners who choose to use a newer or different infill for the new infilled artificial turf, and also those filed owners who choose to bag and haul away the already-used, extracted infill.
It is even yet another object of the present invention to overcome real or potential drainage problems with newly installed infilled artificial turf fields, particularly drainage problems associated with a compacted base that includes limestone fines.
The present invention achieves these objects by modifying an existing infill extractor/collector so as to divert the already-used and extracted infill directly to the top of the compacted base of a preexisting infilled artificial turf, so that the extracted infill can thereafter be incorporated into the top of the compacted base so as to improve the overall drainage characteristics of the artificial turf field to be subsequently installed at the same site. This incorporation of the already-used infill, particularly the crumb rubber, into the top surface of the base mixes resilient particles within the limestone and the sand and helps to maintain vertical infiltration rates, which promotes water drainage and reduces compaction within the upper surface. Preferably, using the infill extractor of the type shown in the PCT '514 application, the extracted infill is placed in windrows next to the strip of turf from which it has just been extracted, and the rows of extracted infill are then spread so as to be evenly distributed onto the compacted base. Thereafter, the base is tilled so as to distribute the extracted infill within the upper 2-3 inches thereof, so as to change the substructure at the top of the base.
The present invention enables an already-used and extracted infill to be repurposed for a newly installed infilled artificial turf, and does so in a manner that eliminates the inconvenience and costs associated with bagging and shipping the extracted infill offsite. More specifically, the present invention eliminates the problems associated with disposing of up to 750,000 pounds of already-used infill. The present invention improves the drainage of the new athletic field, by changing the soil structure at the top of the base so as to maintain vertical infiltration rates. This is particularly true in locations where the “fines” of the base include a significant amount of limestone, and the already-used and extracted infill comprises a mixture of sand and crumb rubber particles, wherein the rubber particles are from reclaimed tires.
According to one aspect of the present invention, the extracted infill is used for the newly installed infilled artificial turf at the same site, except that it is used for a different purpose, namely, that of maintaining acceptable vertical infiltration rates for the compacted base that is located below the newly installed artificial turf.
To practice the present invention in a cost-effective manner on an entire field, while at the same time also accommodating the needs of users who wish to reclaim, clean, or perhaps haul away the preexisting infill, applicant modified its existing infill extractor/collector so as to be operable in either of two modes. The first “conventional mode” is disclosed in the PCT '514 application cited above, whereby infill is collected in bags, i.e. super sacks and then cleaned and/or reused at the same site, or hauled away to a different site. A second mode involves the use of a temporary diverting plate within the frame of the infill collector cart, so as to divert the extracted and collected infill from the turf strip that is being placed back on the base. This lateral diverting of the collected infill occurs via a hole cut in the bottom of the bag. The infill that is extracted, collected, and then conveyed to the cart is then diverted, or redirected, by the diverting plate to create a continuous pile of infill alongside the turf strip that has just been placed back on the base behind the extractor/collector.
There is also an alternate structure for achieving this second mode, by removing the lower first end of the collection auger, and then mounting in its place an outlet or extension to convey the extracted infill directly to the side of the mobile unit.
Those skilled in the art will better understand the present invention by referring to the accompanying drawings, which are described below.
This specification refers to the infill extractor/collector 10 disclosed in the above-described PCT '514 application, and particularly to
Moreover, along with the diverter 24, the bag 14 used in this example includes a hole 14a at the bottom, to enable infill 18 to be diverted laterally away from the travel path of the infill extractor/collector 10.
Thus, as described, the present invention involves a simple modification to an existing device, namely the extractor/collector disclosed in the PCT '514 application, so that that device can be used in its original, or conventional mode, to continue to collect and bag extracted infill from a worn out infilled artificial turf. Alternatively, as shown in
To the extent that the reclaimed crumb rubber from the worn out synthetic turf has not been removed from the field site, but instead has been repurposed into a lower level of the field, within the subsurface, it still remains above the water table. In this condition it presents no greater environmental concern than it previously did, when it resided above the artificial component of the turf as the infill particulate. Moreover, relocating of the crumb rubber particles below the artificial components enables the field owner to make use of newer, more environmentally progressive infills within the artificial turf surface. Thus, the overall environment situation with respect to the water table is made no worse, while the environmental situation with respect to the infill for the artificial turf itself may have been improved.
To test this concept, applicant used three trial plots. One trial plot had an infill comprising 100% rubber. Another one used an infill with a one-to-one ratio of sand and rubber, by weight, and a third trial plot used a two-to-one ratio of sand to rubber, by weight. For each of these three trial plots, applicant mixed in fine gravel, to mimic the tilled result of incorporating an extracted infill into the uppermost surface of a base at an existing field site. Applicant then spread the three sample mixtures over coarse #57 gravel, to simulate the compacted base onto which an artificial turf is typically installed.
For each of the three sample plots, one half of the plot had a pad installed below the artificial turf, while the other half did not have a pad. Artificial turf was then installed over the entire trial area and infilled with a sand/rubber mixture. Applicant took G-Max readings (a measure of surface harness) several days later, in an effort to detect any difference resulting from variation in sand/rubber ratios, the infills, or the presence or the absence of the pad. In each case, the pad resulted in a lower G-Max rating relative to the absence of a pad, but for each of the three plots the sand rubber incorporation ratio made no difference.
Two months later, applicant again took G-Max readings of the three trial plots and again saw no differences based on infill variation. Thereafter, the artificial turf was rolled back from the no-pad halves of the samples to enable the top surfaces of the test bases to be exposed to the elements. After about six weeks, these sample no-pad half sections were analyzed for infill migration. This was done by cutting sections through the incorporation layer and into the #57 gravel layer located therebelow, to determine if any separation, i.e. any horizontal stratification, had occurred between the infill mixture and the fine gravel. No such stratification was detected. In other words, the fine gravel remained thoroughly mixed with the incorporated infill material. Applicant concluded that the infill material remained intermixed with the gravel at the top surface of the base, regardless of the sand/rubber ratio of the infill material. Applicant also concluded that the incorporated mixture minimized the likelihood of compaction over time, and that vertical infiltration rates for the resulting base would be maintained at an acceptable level.
Based on these test results, applicant believes that the present invention eliminates the need for the current field owner to dispose of between 250,000 and 750,000 pounds of extracted infill from the original field, and thereby represents a significant cost savings for the field owner. Moreover, by incorporating the extracted infill into the top surface of the compacted base, the field owner improves on the existing drainage conditions for the base located at the site of the new athletic field. For those who are responsible for removing an existing field and replacing it with a new field, the present invention simplifies that process, by eliminating the need to bag and collect all of the used and collected infill and then to move the bagged and collected infill to another site. The elimination of these steps presents a significant savings of time and cost for these tasks. Further, the present invention eliminates the need to dispose of the infill at a landfill, and thus represents a significant environmental advantage.
Those skilled in the art will understand and appreciate that this specification explains the details of the present invention in the context of several exemplary embodiments, and that those exemplary embodiments are not intended to limit the scope of the present invention, or to be used to limit the scope of the following claims. Further, those skilled in the art will also appreciate that the objects set forth in this specification are not intended to be construed as limitations. Rather, they are intended to provide the reader with a practical understanding of the various benefits achieved via certain aspects of the present invention, particularly according to the presently disclosed preferred embodiments. Also, each claim of this specification recites a combination of subject matter features that applicant considers to be new, useful, and obvious over the prior art, regardless of whether that subject matter achieves one or more of the above-described objects, or maybe even only partially achieves one or more of those objects. This specification explains the story of this invention, i.e. how it came to be, and why it represents an improvement over the existing state of the art. Applicant does not intend for this specification to be used as a roadmap by a would-be infringer to focus unduly on the above-stated objects of the invention, rather than the claims themselves. Stated alternatively, applicant does not intend that each of the appended claims is required to achieve every one of the above-stated objects, and those skilled in the art will understand that.
This application claims priority to PCT Application Serial No. PCT/US2017/052779, filed on Sep. 21, 2017, which claims priority to U.S. Provisional Application No. 62/397,652, filed on Sep. 21, 2016, each of which is expressly incorporated by reference herein, in its entirety.
Number | Date | Country | |
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62397652 | Sep 2016 | US |
Number | Date | Country | |
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Parent | PCT/US2017/052779 | Sep 2017 | US |
Child | 16281358 | US |