Patent Publication Number: US-2019177922-A1

Title: Removable active panel system

Description:
TECHNICAL FIELD 
     The present subject matter relates generally to the field of synthetic turf, and more particularly to a removable active panel system for use in connection with playing surfaces where sections of turf for athletic events may be exchanged or removed between events. 
     BACKGROUND ART 
     Artificial turf fields, pitches, and courts may be utilized in place of natural grass surfaces. An artificial turf field may comprise rows of synthetic ribbons that extend generally vertically from a backing layer. The synthetic ribbons may be designed to resemble grass. An infill layer of particulate material may be interspersed between the ribbons on the backing layer. In this arrangement, the synthetic ribbons are designed to extend a distance above the infill layer of particulate material. The infill may comprise, for example and without limitation, sand, rubber, a mixture of sand and rubber, or other granulated particles such as thermoplastic elastomers or rubbers, EPDM rubber, or cork. The infill of particulate material provides resiliency to the surface and helps keep the ribbons in an upright position. 
     Generally, the ribbons and backing of artificial turf known in the prior art is formed by tufting the ribbons through one or more layers of backing. The backing may comprise a single layer of material or multiple layers of material, and the individual layers may be woven and/or nonwoven material. 
     The tufting is generally performed using a conventional tufting machine analogous to a giant sewing machine with hundreds of needles. Multiple ends of yarn are fed to a bank of heavy needles with a typical span of twelve to fifteen feet. The tufting process involves passing a previously constructed primary backing under the needles and anchoring each stitch. The ribbons are thereby stitched into the backing fabric, leaving loops which form the turf pile. The pile may be loop pile, cut pile, or a combination of cut and loop introduced simultaneously in the turf by pushing off certain loops from the hook before they are cut. 
     Once the ribbons are tufted in place through the primary backing, a secondary backing may be applied to the primary backing. 
     BRIEF SUMMARY 
     With parenthetical reference to the corresponding parts, portions or surfaces of the disclosed embodiment, merely for the purposes of illustration and not by way of limitation, a removable active panel system is provided for installing removable artificial turf panels in a playing surface, the system comprising an artificial turf panel having a plurality of upstanding ribbons extending from a backing layer, at least a portion of the backing layer comprising at least one of a magnet and a ferromagnetic material, a support layer supporting the artificial turf panel and having a channel formed therein, the channel comprising at least one of a magnet and a ferromagnetic material, wherein the artificial turf panel is removably attached to the support layer by magnetic engagement of at least one of the magnet and ferromagnetic material of the artificial turf panel with the other of the at least one of the magnet and the ferromagnetic material of the support layer. 
     The panel may have an infill layer interspersed between the upstanding ribbons extending from the backing layer. The magnet may comprise a permanent magnet. The ferromagnetic material may comprise a permanent magnet. The magnet may comprise an electromagnet. The backing layer may comprise a primary backing layer and a secondary backing layer. The at least one of a magnet and a ferromagnetic material of the backing layer may comprise a magnetic additive in at least a portion of the secondary backing layer. The secondary backing layer may comprise urethane. The at least one of a magnet and a ferromagnetic material of the backing layer may comprise a permanent magnet fixed to at least a portion of the secondary backing layer. The support layer may comprise an elastomeric material. The support layer may comprise a layer of stone, concrete or asphalt disposed below the layer of elastomeric material. The support layer may comprise stone, concrete and/or asphalt. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are incorporated herein as part of the specification. The drawings described herein illustrate embodiments of the presently disclosed subject matter and are illustrative of selected principles and teaching of the present disclosure and do not illustrate all possible implementations thereof. The drawings are not intended to limit the scope of the present disclosure in any way. 
         FIG. 1  is a plan view of a turf system having removable panels according to an embodiment of the present disclosure. 
         FIG. 2  is a plan view of an end zone schematic layout according to an embodiment of the present disclosure. 
         FIG. 3  is a cross-sectional view taken along lines  3 - 3  of  FIG. 2 . 
         FIG. 4  is a schematic diagram depicting the installation of removable panels according to an embodiment of the present disclosure. 
         FIG. 5  is a top view of a schematic diagram depicting steps for forming a channel in an elastomeric layer according to an embodiment of the present disclosure. 
         FIG. 6  is a schematic diagram depicting the formation of an internal seam according to an embodiment of the present disclosure. 
         FIG. 7  is a schematic diagram depicting the installation of removable panels according to another embodiment of the present disclosure. 
         FIG. 8  is a schematic diagram depicting the installation of removable panels according to another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     It is to be understood that like reference numerals are intended to identify the same structural elements, portions or surfaces consistently throughout the several drawing figures, as such elements, portions or surfaces may be further described or explained by the entire written specification, of which this detailed description is an integral part. Unless otherwise indicated, the drawings are intended to be read (e.g., cross-hatching, arrangement of parts, proportion, debris, etc.) together with the specification, and are to be considered a portion of the entire written description of the invention. As used in the following description, the terms “horizontal”, “vertical”, “left”, “right”, “up” and “down”, as well as adjectival and adverbial derivatives thereof, (e.g., “horizontally”, “rightwardly”, “upwardly”, etc.), simply refer to the orientation of the illustrated structure as the particular drawing figure faces the reader. Similarly, the terms “inwardly” and “outwardly” generally refer to the orientation of a surface relative to its axis of elongation, or of rotation, as appropriate. 
     Additionally, it is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. Hence, specific dimensions, directions or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless expressly stated otherwise. 
     Referring now to  FIG. 1 , in an embodiment, a multipurpose artificial turf system  10  includes removable panels  13 . The turf system  10  may include some areas of the turf that are permanently installed and some areas that comprise the removable panels  13 . As illustrated in  FIG. 1 , in an embodiment, the turf system  10  may be installed to create an American football field. In an embodiment, removable panels  13  may be used to decorate special events or may be used for providing individual team logos where more than one team may share the venue for home games. Removable panels  13   a ,  13   b , and  13   c  are located at midfield and may be used to depict logos related to the team, league, or to special events such as championships or all-star games. Removable panels  13   d - k  and removable panels  13   l - s  are located at opposite end zones. The surrounding turf  16  and the remainder of the field  19  are permanently installed. At the top of the figure, additional removable panels  22   a - o  are provided to convert the turf system  10  to a baseball field configuration. Other configurations for additional or alternative playing surfaces such as, without limitation, for a soccer field/football pitch or rugby field, will be evident to those of ordinary skill in the art based on this disclosure. 
     As illustrated in  FIG. 2 , in an embodiment, an American football field end zone portion  25  may be divided into six subsections  28   a - f . In other embodiments, the end zone portion  25  may be divided into any number of sections as will be evident to persons of ordinary skill in the art based on this disclosure. In an embodiment, the end zone portion subsections  28   a - f  provide for attachment of removable panels  31  along their outside edges  34   a - d . The end zone portion  25  has a border area  37  that extends around the periphery of the end zone portion  25 . In an embodiment, the border area  37  may have a width between 2 inches and 6 inches. Interior seam areas  40 ,  43 , and  46  extend between the sides of the border area  37 . In an embodiment, the interior seam areas  40 ,  43 ,  46  may have a width of approximately twice the width of the border area  37 . 
     As illustrated in  FIG. 3 , in an embodiment, the turf system  10  includes several supportive layers. In this embodiment, a first supportive layer  50  may comprise a concrete slab. The first supportive layer  50  may also be referred to as the base layer. A second supportive layer  53  may be provided on top of the concrete slab  50 . In an embodiment, the second supportive layer  53  may comprise stone. The supportive layer  53  may be referred to as an intermediate layer. A third supportive layer  56  may be disposed on top of the second supportive layer  53 . In an embodiment, the third supportive layer  56  may comprise a porous asphalt. A fourth supportive layer  59  of an elastomeric material may be provided on top of the stone and asphalt layers  53 ,  56 , respectively. The additional supportive layers  53 ,  56 ,  59  above the concrete slab  50  provide for drainage and cushioning beneath the artificial turf system playing surface. While a multi-layer support system  50 ,  53 ,  56 ,  59  is shown and described, different numbers and/or types of layers may be used as alternatives without deviating from the present disclosure. For example, and without limitation, the base layer may comprise either porous or non-porous asphalt with a top cushioning elastomeric layer, or the base layer may comprise the only supportive layer beneath the artificial turf system playing surface. 
     A top layer  62  of the artificial turf system  10  is comprised of the artificial or synthetic turf. The top layer  62  includes turf fibers  65  on one side and a backing  68  on the opposite side. The backing  68  may be disposed directly onto the elastomeric layer  59 . In an embodiment, the backing  68  may be permanently attached to the elastomeric layer  59  in certain areas of the field and may be removably coupled with the elastomeric layer  59  in other areas, such as at midfield and the end zones, as removable panels  13 ,  31 . 
     As illustrated in  FIG. 2 , in an embodiment, rails  120  may be disposed in the seam areas  40 ,  43 ,  46  and border areas  37  for supporting one or more trays of natural grass turf. The rails  120  may be disposed generally parallel to the seam areas  40 ,  43 ,  46  and border areas  37  in which they are located, respectively. In an embodiment, the rails  120  may comprise, but are not limited to, steel, aluminum, and/or alloy. One or more removable panels  31  may be removed and one or more trays of natural grass turf may be inserted/supported on the rails  120 . 
     The turf top layer  62  includes a primary backing layer  68  and a plurality of upstanding synthetic ribbons  65  representing blades of grass, extending upwardly from the upper surface of backing layer  68 . In this embodiment, ribbons  65  are fibrillated slit-film and/or extruded polyethylene ribbons. Fibrillation means that the yarn is of a flat, tape-like character and includes longitudinally extending slits across its width. With light brushing, these slits tend to split along the slits into several individual free standing strands of a width that is thinner than the full width of the yarn and thereby more closely resembles blades of grass. 
     In an embodiment, an infill layer  69  may be provided above the top layer  62 . The infill layer  69  may be interspersed between the upstanding ribbons  65  on the backing layer  68 . In this arrangement, the synthetic ribbons  65  are designed to extend a distance above the infill layer  69 . The infill layer  69  may comprise, without limitation, sand, rubber, a mixture of sand and rubber, and/or other granulated particles such as thermoplastic elastomers, rubbers, EPDM rubber, cork and/or organics. The infill layer  69  of particulate material provides resiliency to the top layer  62  and helps keep the ribbons  65  in an upright position. 
     Generally, the ribbons  65  and backing layer  68  are formed by tufting the ribbons  65  through one or more layers of backing  68 . The backing  68  may comprise a single layer of material or multiple layers of material, and the individual layers may be woven and/or nonwoven material. 
     The tufting is generally performed using a conventional tufting machine, which is analogous to a giant sewing machine with hundreds of needles. Multiple ends of yarn are fed to a bank of heavy needles with a typical span of twelve to fifteen feet. The tufting process involves a previously constructed primary backing passing under the needles and anchoring each stitch. The ribbons  65  are thereby stitched into the backing fabric, leaving loops which form the turf pile. The pile may be loop pile, cut pile, or a combination of cut and loop introduced simultaneously in the backing  68  by pushing off certain loops from the hook before they are cut. 
     Once the ribbons  65  are tufted in place through the primary backing, the backing  68  is further coated on its back side with a urethane or latex coating, which may be referred to as a secondary backing, to help adhere the stitched ribbons  65  to the backing member  68  and to provide dimensional stability. In an embodiment, the secondary backing may include fiberglass disposed in the urethane or latex coating. The fiberglass in the secondary backing increases the stiffness of the backing layer  68 . 
     Turning now to  FIG. 3 , in an embodiment, an infill layer  69  may be provided in the top layer  62 . The infill layer  69  may be a mixture of rubber and sand particles interspersed between the upstanding ribbons  65  on the backing layer  68 . In an embodiment, the synthetic ribbons  65  extend a length of about one (1) inch or greater from the upper surface of backing layer  68 . The height of infill layer  69  may extend from about 50% to 80% the height of the ribbons  65 , which means that ribbons  65  extend a distance of about 50% to 20% of their height above the top surface of the infill layer  69 . In other embodiments, other ratios may be used as alternatives. 
     With continued reference to  FIG. 3 , in an embodiment, the end zone area may include three longitudinal channels  71   a - c  disposed in the elastomeric layer  59 . Materials for engaging with the removable active panels  31  may be disposed in the three longitudinal channels  71   a - c , as described in greater detail below. In other embodiments, the number and shape of the channels  71  may be varied as desired. 
     As illustrated in  FIG. 5 , in an embodiment, the elastomeric layer  59  may be disposed on top of the porous asphalt layer  56 . In production of the artificial turf system  10 , the elastomeric layer  59  may be applied to the porous asphalt layer  56  via a paving process as will be evident to those of ordinary skill in the art based on this disclosure. During the paving process, one or more channel forms  93  are positioned where longitudinal channels  71  are desired. In an embodiment, the forms  93  may be constructed of a sturdy lightweight material such as, but not limited to, aluminum. The forms  93  fill the space for the channels  71  to prevent elastomeric material  59  from entering the channel space during paving. After the elastomeric layer  59  dries and sets/cures, the forms  93  are removed. Alternatively, and without limitation, the layer  59  may be applied as a continuous flat surface and channels  71  may thereafter be cut, ground, or otherwise formed via a subtractive process into layer  59 . At this stage of production, the channels  71  are longitudinal empty spaces located in the portion of the elastomeric material  59  defining the seam areas  40 ,  43 ,  46  and border areas  37  (see  FIG. 2 ). The attachment of the removable turf panels  31  is described in greater detail below. 
     As illustrated in  FIG. 7 , in an embodiment, the removable turf panels  31  may include a plurality of bars  100  containing a ferromagnetic material such as iron or the like. The ferromagnetic bars  100  may be disposed in the backing layer  68  of the removable panel top layer  62 . Alternatively, the ferromagnetic material may be formed as a unitary structure (not depicted). In an embodiment, the longitudinal channel  71  may be provided with a pad  75  for permanent attachment to the third supportive layer  56 . In an embodiment, a permanent magnet  103  may be disposed on the pad  75  in the channel  71 . As an alternative, the permanent magnet  103  may be disposed on the backing layer  68  of removable panel  31  and the ferromagnetic material may be disposed on the pad  75 . 
     As another alternative, the backing layer  68  may be provided with a number of magnetic strips  100 A and corresponding magnetic strips  103 A may be provided on the pad  75  in the channels  71 , or in the channels  71  without a pad  75 . In an embodiment, the magnetic strips  100 A,  103 A may comprise flexible magnet sheets. The magnet sheets may include a ferromagnetic material integrated with a polymeric material or other flexible binder. In an embodiment, the magnetic strips  100 A,  103 A may be separated with a relatively small pull force normal to the field surface to facilitate efficient removal of the removable panels  31 . However, to ensure that shear forces applied to the removable panels  31  during an athletic event do not cause shifting of the removable panels  31 , the magnetic attraction between the magnetic strips  100 A,  103 A is greater in a plane parallel to the playing surface than in a plane normal to the playing surface. Thus, magnetic strips  100 A,  103 A have a magnetic attraction that provides improved dimensional stability parallel to the playing surface to prevent shear slip of the removable panel  31  relative to the multi-layer support system  50 ,  53 ,  56 ,  59 . 
     In an embodiment, the inside surface of one or more of the magnetic strips  100 A,  103 A may have a high coefficient of friction material applied thereto. The high coefficient of friction material may include, but is not limited to, a polymeric material. In an embodiment, to prevent shear slip of the removable panels  31 , a rough coating may be applied between the magnetic strips  100 A,  103 A. 
     When the panel  31  is aligned with the channel  71  and pushed down in the direction of arrow  106 , the ferromagnetic material  100  and the permanent magnet  103  attract and provide a magnetic force to hold the panel  31  in position in the turf system  10 . The magnetic bond is strong enough to hold the turf panel  31  securely in position, but may be manually separated during removal of the turf panel  31 . As an alternative, the permanent magnet  103  may be replaced by an electromagnet which becomes magnetic when energized by an electrical current and/or the ferromagnetic material  100  may comprise permanent magnets. 
     Turning to  FIG. 8 , an alternate embodiment is shown. In this embodiment the backing  68  of the turf panel is provided with an additional secondary layer  107  formed from a plastic or elastomeric resin or urethane containing a magnetic additive or a magnetic powder. In addition, or as an alternative, the primary backing  68  may be provided with a magnetic additive or magnetic powder. As illustrated in  FIG. 8 , the magnet for engaging with the ferromagnetic material in the backing  68  may be an electromagnet  109  provided with a current through an electrical circuit  110  connected thereto. 
     Turning now to  FIG. 4 , in an alternative embodiment, the attachment of the removable turf panels  31  may include a hook and loop system  78 ,  81 . As illustrated in  FIG. 4 , a removable turf panel  31  is attached along edge  34   c  to the border area  37 . The longitudinal channel  71   c  is provided with a pad  75  for permanent attachment to the sublayer. As shown, pad  75  is supported by the porous asphalt layer  56 . Alternatively, the pad  75  may be supported by a different sublayer or a partial layer  59  of elastomeric material. The pad  75  may have a top surface  79  that is provided with a hook and loop fastening material  78 . The pad  75  is constructed of any material suitable for attachment to a sublayer on one side and for attachment of the hook and loop fastening material  78  on the opposite side. The removable panel  31  may also be provided with hook and loop fastening material  81  disposed on the backing layer  68 . The hook and loop fastening material  81  attaches to the corresponding hook and loop fastening material  78  when the panel  31  is positioned and a force is applied in the direction of arrow  90 . 
     Turning to  FIG. 6 , an internal seam such as located along interior seam area  40  ( FIG. 2 ) is shown. The edges of two adjacent panels  31  are disposed adjacent to each other and removably attached by means of cooperating hook and loop fastening materials  78 ,  81 . 
     One or more features of the embodiments described supra may be combined to create additional embodiments which are not depicted. The present invention contemplates that many changes and modifications may be made. Therefore, while the presently-preferred form of the removable active panel system has been shown and described, and several modifications and alternatives discussed, persons skilled in this art will readily appreciate that various additional changes and modifications may be made without departing from the scope of the invention.