Patent Publication Number: US-10786949-B2

Title: Ultrasonically welded mat unit and system thereof

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation Application of U. S. patent application Ser. No. 15/928,893, filed on Mar. 22, 2018, which is a Continuation Application of U.S. patent application Ser. No. 15/435,981 filed Feb. 17, 2017, now U.S. Pat. No. 9,944,017, which claims priority to U.S. Provisional Application Ser. No. 62/335,141, filed on May 12, 2016; the disclosures of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates generally to flooring systems. Particularly, the present disclosure relates to mat systems, their directional cleaning of shoes, and their method of fabrication. Specifically, the present disclosure relates entrance mats configured to remove debris from shoes moving in any direction and that are fabricated from non-vinyl materials that do not release noxious chemicals and do not require adhesives to join multiple layers together. 
     Background Information 
     Entrance matting is often considered an essential safety item in commercial, industrial, and residential facilities, Generally, there are a significant number of types of matting for all types of needs. By way of non-limiting example, industrial facilities usually purchase entrance matting in areas where floors tend to be slippery from production residue or moisture. Offices with heavy walk-in traffic and normal employee traffic often purchase matting to create a safe treading condition as well as to protect the floor. Retail stores may have similar entrance matting as well. 
     Entrance matting also helps to prevent tracking dirt and water onto other floor areas. Some mats incorporate an absorbent upper layer to soak up water, snow, and other debris. 
     Typically, entrance mats and matting systems are fabricated from vinyl-based polymers. These materials may be molded into specific shapes and designs. However, the molding process requires that the vinyl-based material be heated to sufficiently mold it to the desired shape. 
     When the temperature of the vinyl-based material is raised for the molding process, there exists a potential danger for the release of noxious and potentially harmful or even toxic off gasses. 
     Even after the material has been formed to a desired shape, often two layers of formed material may be joined together with adhesive. Or, the absorbent top layer may be applied with adhesive. These adhesives may also release harmful or noxious odors/chemicals during the adhesive bonding and curing process 
     SUMMARY 
     Issues continue to exist with mats and mat systems fabricated from vinyl-based materials, and from the fabrication of mat systems requiring adhesive to bond some components together. Thus, a non-vinyl based mat and mat system that can be free of adhesives is needed. The present disclosure address these and other issues. 
     In one aspect, an embodiment of the present disclosure may provide a mat unit that is formed from at least two layers ultrasonically welded together. Each layer is individually formed form non-vinyl nontoxic thermoplastic elastomer (TPE) material. In ultrasonically joining the two layers together, there is no need to use additional materials, such as adhesive (i.e., chemical attachment) or stitched thread (i.e., mechanical attachment) to form the joint/weld point. Once formed from the two layers, the mat unit has four quadrants and a plurality of longitudinal ribs integrally formed in the first layer positioned in the first and third quadrants, and a plurality of transverse ribs integrally formed in the first layer positioned in the second and fourth quadrants. Additionally, there are a plurality of longitudinal ribs integrally formed in the second layer positioned in the second and fourth quadrants, and a plurality of transverse ribs integrally formed in the second layer positioned in the first and third quadrants. 
     In another aspect, an embodiment of the present disclosure may provide a method comprising the steps of: forming a first layer of a mat unit from non-vinyl nontoxic thermoplastic elastomer (TPE) material; forming a second layer of the mat unit from non-vinyl nontoxic TPE materials; curing, at least partially, the first and second layers; adjoining the first layer in direct contact with the second layer at a plurality of intersecting welding contact points; and welding the first and second layers together ultrasonically without any additional material bonding the first and second layers together. In this example, the step of forming the first layer may include the steps of: forming a plurality of transversely extending linear ribs; and forming a plurality of longitudinally extending linear ribs. This example may also include wherein the step of forming the second layer includes the steps of: forming a plurality of transversely extending linear ribs; forming a plurality of longitudinally extending linear ribs; and wherein the step of adjoining the first layer in direct contact with the second layer further includes the step of overlaying a transversely extending linear rib on the first layer with a longitudinally extending linear rib on the second layer; and overlaying a longitudinally extending linear rib on the first layer with a transversely extending rib on the second layer. This example may also include the steps of: forming a second mat unit identical to the first mat unit; aligning the second mat unit next to the first mat unit; connecting the first mat unit to the second mat unit with complementary male-female connectors. Further, this example may include the step of building a box-weave pattern from a plurality of mat units, each mat unit in the plurality ultrasonically formed identical to the first mat unit. 
     In yet another aspect, an embodiment of the present disclosure may provide an ultrasonically formed mat unit comprising: a first layer ultrasonically joined to the a second layer at a contact weld point formed from only material of the first and second layers; four quadrants, including a first quadrant, a second quadrant, a third quadrant, and a fourth quadrant; a plurality of longitudinal ribs integrally formed in the first layer positioned in the first and third quadrants, and a plurality of transverse ribs integrally formed in the first layer positioned in the second and fourth quadrants; and a plurality of longitudinal ribs integrally formed in the second layer positioned in the second and fourth quadrants, and a plurality of transverse ribs integrally formed in the second layer positioned in the first and third quadrants. 
     In yet another aspect, an embodiment of the present disclosure may provide mat unit comprising: four quadrants defined by an imaginary transverse midline perpendicularly intersected an imaginary longitudinal midline; an upper surface spanning the four quadrants; a lower surface spanning the four quadrants below the upper surface; a transversely extending first rib forming a portion of the upper surface in a first quadrant; a longitudinally extending second rib forming a portion the upper surface in a second quadrant; a transversely extending third rib forming a portion of the upper surface in a third quadrant; and a longitudinally extending fourth rib forming a portion of upper surface in a fourth quadrant. This embodiment may further a plurality of transversely extending ribs integrally formed in the first layer positioned in the first and third quadrants, wherein the plurality of transversely extending ribs define gaps therebetween adapted to permit debris removed from a shoe to fall therethrough. 
     Additionally, this embodiment may provide a plurality of longitudinally extending ribs integrally formed in the first layer positioned in the second and fourth quadrants, wherein the plurality of longitudinally extending ribs define gaps therebetween adapted to permit debris removed from a shoe to fall therethrough; and a plurality of longitudinal ribs integrally formed in the second layer positioned in the second and fourth quadrants, and a plurality of transverse ribs integrally formed in the second layer positioned in the first and third quadrants. Furthermore, this embodiment may provide a first side spaced from a second side, wherein the imaginary longitudinal midline extends from the first side to the second side; a first end spaced form a second end, wherein the imaginary transverse midline extends from the first end to the second end; wherein the first quadrant is positioned 180° from the third quadrant, and the second quadrant is positioned 180° from the fourth quadrant; a first male connector in the first quadrant and a first female connector in the first quadrant, wherein the first male connector is positioned orthogonal relative to first female connector. 
     In this embodiment, there may also be a second male connector in the second quadrant and a second female connector in the second quadrant, wherein the second male connector is positioned orthogonal relative to second female connector; and wherein the second male connector is substantially parallel to the first female connector, and the second female connector is substantially parallel to the first male connector. The first and second male connectors and the first and second female connectors may be formed integrally with the plurality of transversely extending ribs integrally and the plurality of longitudinally extending ribs from a non-vinyl nontoxic thermoplastic elastomer (TPE) material. The upper surface formed from TPE material may be ultrasonically welded to lower surface which is also formed from TPE material, wherein the ultrasonic weld location of the upper surface to the lower surface is uniform across a weld junction defining a permanent connection of the lower surface to the upper surface. The second and fourth quadrants orthogonally adjacent the first quadrant may include an opposite gender connector aligned in a parallel plane with the respective first male and female connectors of the first quadrant. 
     In another aspect, an embodiment of the present disclosure may provide an omnidirectional travel path associated with customer movement atop the upper surface, wherein a plurality of ribs in each quadrant collectively remove debris from shoes moving in any direction. The travel path is offset parallel to an imaginary longitudinal midline extending from a first side to a second side of the mat, wherein the travel path first passes over a longitudinally aligned gap formed in the upper surface and then passes over a transversely aligned gap formed in the upper surface, wherein the transversely aligned gap is orthogonal to the longitudinally aligned gap. Alternatively, the travel path may be offset parallel to an imaginary transverse midline extending from a first end to a second end of the mat, wherein the travel path first passes over a transversely aligned gap formed in the upper surface and then passes over a longitudinally aligned gap formed in the upper surface, wherein the transversely aligned gap is orthogonal to the longitudinally aligned gap. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       A sample embodiment of the disclosure is set forth in the following description, is shown in the drawings and is particularly and distinctly pointed out and set forth in the appended claims. The accompanying drawings, which are fully incorporated herein and constitute a part of the specification, illustrate various examples, methods, and other example embodiments of various aspects of the disclosure. It will be appreciated that the illustrated element boundaries (e.g., boxes, groups of boxes, or other shapes) in the figures represent one example of the boundaries. One of ordinary skill in the art will appreciate that in some examples one element may be designed as multiple elements or that multiple elements may be designed as one element. In some examples, an element shown as an internal component of another element may be implemented as an external component and vice versa. Furthermore, elements may not be drawn to scale. 
         FIG. 1  is a top plan view of a mat system formed from connected mat units, and more particularly four mat units are shown connected together; 
         FIG. 2  is a top plan view of a single mat unit having four quadrants; 
         FIG. 3  is a bottom plan view of the single mat unit; 
         FIG. 4  is a side elevation view taken along line  4 - 4  in  FIG. 2 ; 
         FIG. 5  is an enlarged side elevation view of the region labeled “SEE  FIG. 5 ” in  FIG. 4 ; 
         FIG. 6  is an enlarged top perspective view of a first quadrant of a single mat unit; 
         FIG. 7  is an enlarged top plan view of the region labeled “SEE  FIG. 7 ” in  FIG. 1  depicting the connection between adjoining mat units; 
         FIG. 8  is a transverse cross section taken along line  8 - 8  in  FIG. 7  depicting the connection between adjoining mat units; 
         FIG. 9  is a longitudinal cross section taken along line  9 - 9  in  FIG. 7  depicting the connection between adjoining mat units; 
         FIG. 10  is an environmental top plan view of the mat system depicting omnidirectional paths of travels of persons moving atop the mat system; and 
         FIG. 11  is a flow chart detailing an exemplary method of fabricating the single mat unit from non-vinyl materials. 
     
    
    
     Similar numbers refer to similar parts throughout the drawings. 
     DETAILED DESCRIPTION 
     As depicted in  FIG. 1 , a mat system  100  is shown as having a plurality of interconnected or interlocked single tiles or mat units  10 . When the plurality of mat units  10  are connected together, the assembled mat system  100  forms a general basket weave pattern when viewed from above. 
     As depicted in  FIG. 2 , a single tile or mat unit  10  includes a first side  12  opposite a second side  14  defining a longitudinal direction therebetween, a third side  16  opposite a fourth side  18  defining a transverse direction therebetween, and an upwardly facing top surface  20  opposite a downwardly facing bottom surface  22  defining a vertical direction therebetween. Single mat unit  10  further includes four quadrants, namely, a first quadrant  24 , a second quadrant  26 , a third quadrant  28 , and a fourth quadrant  30 . The quadrants are defined by a transversely extending midline  32  perpendicularly intersecting a longitudinal midline  34 . 
     Each quadrant defines a portion of a pair of connectors. Male connectors  36  extend outwardly from the side of the respective quadrant. Each quadrant defines female connectors  38  which are offset generally orthogonally to male connectors  36 . Additionally, in an adjacent quadrant, an opposite gender connector is substantially coplanar with an opposite gender connector of the first quadrant. For example, looking towards the first quadrant  24 , the male connectors  36   a  extend outwardly to the right when viewing single tile unit  10  from above. Female connectors  38   a  are adjacent first side  12  and the second quadrant  26  is positioned to the left or towards the third side  16  and has male connectors  36   b  extending in the same direction of the first side  12  as the female connectors  38   a . Female connectors  38   b  in second quadrant  26  are generally aligned longitudinally orthogonal to that of male connectors  36   b  in second quadrant  26 . Stated otherwise, within each quadrant, the female connectors  38  are aligned in a single direction and the male connectors  36  are aligned in an orthogonal direction to that of female connectors  38 . Male connectors  36  offset to one side of longitudinal midline  34  lie in the same direction as female connectors  38  on an opposite side of midline  34 . For example, male connectors  36   c  in the third quadrant  28  are arranged in the same direction as female connectors  38   d  in the fourth quadrant  30  opposite longitudinal midline  34 . Male connectors  36  are arranged in the same direction as female connectors  38  opposite transverse midline  32 . For example, male connectors  36   b  in the second quadrant  26  are arranged in the same direction as female connectors  38   c  in the third quadrant  28 . The spacing of connectors  36 ,  38  on single mat unit  10  enables unit  10  to be assembled with other identical tile units in order to construct a flooring mat system as shown in  FIG. 1  and as will be described in greater detail below. 
     Each mat unit  10  includes an upper first layer  40  and a lower second layer  42 . Upper layer  40  may also be referred to as a first layer  40 . Lower layer  42  may also be referred to as a second layer  42 . The upper layer  40  includes a plurality of transversely extending linear ribs  44  and a plurality of linearly extending longitudinal ribs  46 . In the shown embodiment of  FIG. 2 , the transverse linear ribs  44  are positioned in the first quadrant  24  and the third quadrant  28  which is aligned diagonally or 180° from the first quadrant  24 . The plurality of longitudinally extending linear ribs  46  are disposed in the second quadrant  26  and the fourth quadrant  30 . The second quadrant  26  is diagonally opposite the fourth quadrant  30  or 180° therefrom. Arranging the transverse linear ribs in a quadrant 180° from the next set of transversely extending linear ribs creates a basket weave pattern which may also be referred to as a standard block pattern of a plurality of mat rib units when they are assembled in a flooring system. One exemplary and non-limiting distinction of the mat system  100  utilizes units  10  is that each unit  10  includes the upper surface altering directions in each quadrant. Thus, if an installer desired to create a basket weave pattern with conventional slotted mats, it would require four individual mat units positioned orthogonal relative to each other, whereas mat unit  10  accomplishes this feat in a single unit, rather than a combination of four. 
     As depicted in  FIG. 3 , lower layer  42  includes a plurality of transversely extending lower layer linear ribs  48  and a plurality of longitudinally extending lower layer linear ribs  50 . The lower level transverse linear ribs  48  are positioned beneath portions of the upper layer  40  that form longitudinal linear ribs  46 . For example, lower level transverse linear ribs  48  formed in lower layer  42  are positioned vertically beneath longitudinal linear ribs  46  formed in upper layer  40 . Thus, the lower layer transverse linear ribs  48  are formed in the second quadrant  26  and the fourth quadrant  30 . Additionally, since the lower level ribs are orthogonal to the top upper layer ribs, the plurality of lower level longitudinal linear ribs  50  are formed beneath portions of the upper layer  40  that define transverse linear ribs  44 . Thus, the lower level longitudinal ribs  50  are formed in the first quadrant  24  and the third quadrant  28 . For example, first quadrant  24  includes lower level longitudinal layer ribs  50  and third quadrant  28  includes lower level longitudinal linear ribs  50  which are each vertically beneath transverse linear ribs  44  formed in the upper layer  40 . The orthogonal arrangement between the upper layer  40  and the lower layer  42  provides overall rigidity and strength to mat unit  10 . Additionally, lower layer  42  may include a plurality of gripping feet  52  arranged throughout the lower layer extending from the downwardly facing bottom surface  22  such that feet  52  engage a subfloor surface. 
     As depicted in  FIG. 4  and  FIG. 5 , the male connectors  36  and the female connectors  38  are offset on opposite sides of longitudinal midline  34  with respect to a single mat unit  10 . In one particular embodiment, two female connectors are positioned offset on the same side relative to longitudinal midline  34 . More particularly, a first female opening  60  is positioned outwardly relative to a second female connector  62  which is positioned inwardly closer to longitudinal midline  34 . The first and second female openings  60 ,  62  are bound by upper most edge  64  which is located approximately half way relative to the vertical height  66  which may also be referred to as thickness  66  of mat tile unit  10 . 
     In one particular embodiment, thickness  66  is preferably less than 0.5 inches so that mat tile unit  10  may fit beneath low clearance doors more easily. Furthermore, it may be desirable for the mat thickness  66  to be not more than about 0.4 inches to ensure proper clearance under low hanging doors. 
     The opening to first female connectors  38  forms a generally L-shaped passageway which will be described in greater detail below. Only a first leg  68  of the L-shaped passageway is seen in  FIG. 4  inasmuch as the second leg  70  ( FIG. 8 ) extends upwardly through the mat  10 . The L-shaped passageway is configured to receive one of the male connectors  36  which is shaped complementary to the L-shaped passageway as indicated in  FIG. 5 . 
     With continued reference to  FIG. 5 , the male connectors  36  may be an equal number of connectors to that of the opposite gender. In this instance, there are two male connectors  36  located offset to one side of longitudinal midline  34 . Each male connector  36  is generally L-shaped including a horizontally extending first leg  72  and a vertically extending second leg  74 . The first horizontal leg  72  extends outwardly from a vertical sidewall  76 . Upwardly facing top surface of first leg  72  is located approximately halfway relative to the vertical thickness  66  such that it corresponds to fit beneath a top edge  64  of female connector  38 . Furthermore, first leg  72  has a horizontal length complementary to that of first passageway leg  68  of female connector  38  to enable the horizontal leg  72  of male connector  36  to slidably be received therein. The second vertical leg  74  extends upwardly from a rigid connection with the top surface of first horizontal leg  72  and is spaced apart from vertical sidewall  76  defining a gap  80  therebetween. Gap  80  has a spaced apart distance complementary to that of a portion of the mat defining the L-shaped passageway of female connector  38  to enable the top portion of the mat  10  to be received in gap  80 . When the male connector  36  is attached to the female connector  38 , top edge  64  of female connector  38  is disposed entirely within gap  80  between vertical wall  76  and vertical leg  74 . 
     Second leg  74  is capped with a cap member  82 . Cap  82  includes a length that is greater than that of the second vertical leg  74  upon which cap  82  resides. The greater length of cap  82  defines an overhang  84  on each side of cap  82 . Overhang  84  may further be defined by inwardly and upwardly tapering edge  86 . Cap  82  may further include one or more upwardly extending nubs  88  extending upwardly from the top surface of cap  82  but terminating below the upwardly facing top surface  20  of upper layer  40 . 
     As depicted in  FIG. 6 , the plurality of longitudinally extending linear ribs  46  are spaced apart from each other preferably at even intervals defining gaps  90  therebetween. The gaps  90  are also aligned longitudinally similar to that of linear ribs  46 . Within each gap  90  are a plurality of lower support members  92  which act as secondary ribs to extend between adjacent spaced apart pairs of linear ribs  46 . The secondary ribs, or support members  92 , are short pieces of material spaced apart from each other within a gap  90  and oriented orthogonal to that of the ribs they extend between. For example, in  FIG. 6 , with the longitudinally extending ribs  46 , the secondary ribs or support members  92 , would be generally aligned in the transverse direction. The same holds true for the second quadrant  26 . However, with respect to the first quadrant  24  and the third quadrant  28  that has transversely extending ribs  44  defining gaps therebetween, the secondary ribs or support members  92 , in the first quadrant  24  and in the third quadrant  28  are oriented in the longitudinal direction which is orthogonal to that of transverse ribs  44 . Secondary ribs  92  are considered part of the upper layer  40  inasmuch as they are formed during the upper layer formation process as will described in greater detail below. The secondary ribs  92  include an upwardly facing top surface that is disposed at a lower vertical level than upper surface  20  defined by ribs  44  and ribs  46 . 
     Preferably, the upwardly facing top surface of secondary ribs  92  is at a similar vertical height of the upwardly facing top surface of nubs  88 . Additionally, with respect to nubs  88 , the secondary ribs  92  in a respective quadrant are oriented orthogonal to the nubs  88  on male connector  36 . For example, as depicted  FIG. 7 , nubs  88  are aligned generally in the transverse direction similar to that of transversely extending linear ribs  44  and the secondary nubs  92  are generally aligned in a longitudinal direction. The same holds true for the remaining quadrants. When nubs  88  are aligned orthogonal to secondary ribs  92  in a respective quadrant, it enables the nubs  88  to be aligned complementary to the nubs  88  in adjoining mat tile unit  10  which will be described in greater detail below. 
     As depicted in  FIG. 7 , when two adjoining mat tile units  10  are connected they form a union  94 . In this example, union  94  is defined between a third quadrant  28 A on a first mat tile unit  10 ′ and fourth quadrant  30 B on a second mat tile unit  10 ″. Furthermore, the outermost edges defined by sidewall  76  may be flush when first mat  10 ′ is connected with second mat  10 ″. There may be some instances where the vertical sidewall  76  forms the outermost edge of the assembled mat system. In this instance, an operator would cut off the outwardly extending male connectors  36  by slicing through first legs  72  with a utility knife or other sharp object to enable the assembled mat tile system to be flushly mounted against a wall of the building structure in which the mat tiles  10  or system  100  are to be installed.  FIG. 7  depicts the assembled tile units prior to the male connectors  36  being slidably removed from fourth quadrant  30 B on second mat tile unit  10 ″. 
     As depicted in  FIG. 8 , the L-shaped male connector  36 , including first leg  72  and second leg  74 , fits in the complementary L-shaped passageway of female connector  38 . When male connector  36  is connected with female connector  38 , the downwardly facing bottom surface of first leg  72  is flush with the bottom surface  42  of second layer  22 . The upwardly facing top surface of second leg  74  is generally flush with upwardly facing top surface  40  of upper layer  20 . An outer perimeter rib  46 A defines surface  76  and is positioned in gap  80 . Note: the outer perimeter rib  46 A is in the second quadrant  26  and fourth quadrant  30  and an outer perimeter rib  44 A corresponds to the first and third quadrants. 
       FIG. 9  depicts the connection of male connector  36  with female connector  38 . Particularly, the overhang  84  on cap  82  is received by and is supported on a ledge  96  defining a portion of the passageway of female connector  38 . When assembled, the overhang  84  acts similar to a hook to substantially preclude male connector  36  from disconnecting with female connector  38 . Stated otherwise, male connector  36  is one-way flexible which enables the male connector  36  to pass upwardly through the vertical portion  70  of L-shaped passageway of female connector  38  such that the overhang  84  flexes downwardly and tapered wall  86  moves upwardly over ledge  96 . When the terminal end of tapered wall  86  passes vertically above ledge  96 , it flexes outwardly and rests above ledge  96 . The tapered wall  86  provides structural support to preclude downward movement of male connector  36  such that male connector  36  is effectively hooked to female connector  38  to ensure that adjoining mat tile units  10 ′ and  10 ″ remain connected together when the system  100  is fully assembled as indicated in  FIG. 10 . 
       FIG. 10  depicts a plurality of individual mat tile units  10  assembled together to form an omnidirectional mat cleaning system  100 . System  100  enables a person walking above the connected mat tile units  10  to have their shoes cleaned regardless of the direction from which they enter a building structure  102 . For example, a first individual  104  may be moving in the direction of arrow A. While moving in the direction of arrow A, the first individual  104  may have their shoes cleaned by the plurality of ribs that are aligned generally orthogonal to the direction of travel along arrow A. A second individual  106  may be moving in the direction of arrow B which is generally orthogonal to that of arrow A. The second individual  106  may have their shoes cleaned by the plurality of ribs that are aligned generally orthogonal to the direction of travel of second individual  106  along arrow B. Similarly, third individual  108  may be entering the building  102  from another direction moving in the direction of arrow C and may have their shoes cleaned by the portions of mat tile units  10  that are aligned orthogonal to the directional movement along arrow C.  FIG. 10  further depicts one or more sliding doors  110 , as one as having ordinary skill in the art would understand, to provide ingress and egress through door openings  112  defined by building structure  102 . As discussed above, doors  110  may be low profile doors that require the thickness  66  of the assembled mat system  100  to be of a substantially low profile and not having a thickness greater than about 0.4 inches. 
     Traditionally, flooring mats are fabricated from vinyl and other polymers which manufacturers believe increases the durability of the mat. However, the use of vinyl during the fabrication process, which is often molded plastic, releases a plurality of noxious and potentially toxic off gases which are clearly harmful both to human machine operators and the environment in general. In conventional two-layer mat systems having an upper layer and a lower layer, when each layer is formed of vinyl, the upper layer and lower layer are adhered together with an adhesive and pressure is applied between the upper layer and lower layer until the adhesive cures securing the upper and lower layer together. 
     In accordance with one aspect of the present disclosure, single mat unit  10  is fabricated from a non-vinyl/TPE material. In doing so, single mat unit  10  upper layer  40  and lower layer  42  incorporate green technology to eliminate any noxious or toxic or noxious off gases during the molding process of upper layer  40  and lower layer  42 . Further, fabrication of single mat unit  10  eliminates the need for any adhesive to bind the upper layer  40  to lower layer  42  during unit  10  fabrication. 
     Upper layer  40  and lower layer  42  fabricated from non-vinyl TPE allow these respective layers to be permanently and fixedly joined together through an ultrasonic welding process. Particularly, upper layer  40  is formed within a mold from non-vinyl TPE. Then, lower layer  42  is formed from non-vinyl TPE in a mold. The lower layer and the upper layer are orthogonally aligned such that their respective longitudinal and transverse linear ribs intersect each other at right angles. Then, with the upper layer and the lower layer adjoining each other, they are operatively connected to an ultrasonic welding machine which produces a high frequency sonic wave to excite the non-vinyl TPE particles in each of the upper layer  40  and lower layer  42 . As the particles forming the respective layers are excited through the ultrasonic welding machine, the particles rapidly excite and bond with each other creating a uniform material defining a permanent junction between the upper layer  40  and lower layer  42  at welding contact points. After the ultrasonic welding machine has been deactivated, mat  10  is allowed to cure. Single mat unit  10  is fabricated from the two layers permanently joined together free of any adhesive between the upper layer and the lower layer. Further, there is no mechanical attachment devices (i.e., stitching or nuts/bolts/screws) connecting the first layer to the second layer. 
     Typically, the ultrasonic welding device or system utilized to join the first layer  40  with the second layer  42  may include press to put the two parts (i.e., the first layer  40  and the second layer  42 ) to be assembled under pressure. The ultrasonic welding device may also include a nest or anvil where the parts (i.e., the first layer  40  and the second layer  42 ) are placed and allowing the high frequency vibration to be directed to the interfaces (the welding contact points). The ultrasonic welding device may also include an ultrasonic stack composed of a converter or piezoelectric transducer, an optional booster and a sonotrode. These elements electrically and acoustically cooperate and are specifically tuned to resonate at the same exact ultrasonic frequency (Typically 20, 30, 35 or 40 kHz). Other common frequencies used in ultrasonic welding of thermoplastics are 15 kHz, 20 kHz, 30 kHz, 35 kHz, 40 kHz and 70 kHz. The ultrasonic welding device may also include a converter configure to convert an electrical signal into a mechanical vibration. The ultrasonic welding device may also include a booster that modifies the amplitude of the vibration. It may also be used in standard systems to clamp the stack in the press. The ultrasonic welding device may also include a sonotrode to apply the mechanical vibration to the parts (i.e., the first layer  40  and the second layer  42 ) to be welded. The ultrasonic welding device may also include an electronic ultrasonic generator delivering a high power AC signal with frequency matching the resonance frequency of the stack. The ultrasonic welding device may also include a controller controlling the movement of the press and the delivery of the ultrasonic energy. 
     In operation and as depicted in the flow chart of  FIG. 11 , a method of fabricating a mat unit  10  for a flooring mat system is generally shown at  400 . Forming a first layer, such as the upper layer  40 , from non-vinyl nontoxic thermoplastic elastomer (TPE) material is shown generally at  402 . This step may be accomplished by molding the first layer in a mold to a desired shape. As shown in the figures, the shape of the first layer is typically rectangular having four quadrants, wherein alternating quadrants can include longitudinally extending and transversely extending linear ribs. 
     Then, forming a second layer, such as the lower layer  42 , from similar non-vinyl nontoxic TPE material is generally depicted at  404 . This step may be accomplished by molding the first layer in a mold to a desired shape. As shown in the figures, the shape of the second layer is typically rectangular having four quadrants, wherein alternating quadrants can include longitudinally extending and transversely extending linear ribs that are offset one quadrant (i.e. rotated 90 degrees) from the design of the first layer. 
     The first and second layers may be allowed to at least partially cure, which is generally depicted at  406 . Then, adjoining the first layer in direct contact with the second layer at a plurality of intersecting welding contact points, which is generally indicated at  408 . 
     Thereafter, welding the first and second layers together ultrasonically without any additional material bonding the first and second layers together, wherein the non-vinyl nontoxic TPE material is uniform at the welding contact points is shown generally at  410 . The step of welding the first and second layers together ultrasonically may be accomplished on a ultrasonic welding machine, which by way of non-limiting example may use high-frequency ultrasonic acoustic vibrations locally applied to the upper layer  40  and lower layer  42  being held together under pressure to create a solid-state weld at the welding contact points. In ultrasonic welding, there are no connective bolts, nails, soldering materials, or adhesives necessary to bind the materials together. 
     Once the first and second layers have been ultrasonically joined together, the manufacturer may add additional components to the assembled mat unit. For example, the mat unit may have non-slip material coupled to the upwardly facing top surface in order to prevent a person from walking on the assembled mat system from slipping or falling. Alternatively, other materials may be coupled to the upwardly facing top surface in remove debris from a shoe as a person walks over the mat. In some versions, this step may allow the use of a non-toxic adhesive to attach the debris removing or non-slip materials to the upper layer  40 . However, there are ways to form the mat tile unit such as having a groove formed in the upwardly facing top surface that receives a non-slip material or debris removing material in a frictional interference fit. 
     Subsequent to the steps of forming a mat unit  10 , the mat units  10  may be packaged and sold to a customer or distributor for installation. In one particular non-limiting embodiment, the mat units  10  are installed in an entranceway to a commercial business ( FIG. 10 ). The assembled mat systems serves the purpose of removing debris from shoes prior to a customer entering a store. Additionally, the assembly mat system may reduce the likelihood of a person slipping when entering the store. 
     As depicted in  FIG. 7 ,  FIG. 8 , and  FIG. 9 , during installation of mat system  100 , a single mat unit  10  is aligned side-to-side with another identical mat unit. The arrangement of the male and female connectors on each mat unit enable the two mat units arrange side-to-side to connect. For the purpose of this example, the two mat units will be referred to as a left unit (such as  10 ″) and a right unit (such as  10 ′) for explanative purposes, however it should be understood that these directions are non-limiting and used for ease of explanation. 
     A left mat unit  10 ″ may be placed to the left of a right mat unit  10 ′. The left unit  10 ″ may have at least two female connectors on its right side. The right unit  10 ′ may have at least two male connectors on its left side. Thus, when the left and right units are placed side-to-side, an installer may connect the male connector of the right unit  10 ′ with the female connector of the left unit  10 ″. 
     The installer may continue this pattern of connecting adjacent male-female connectors to construct the mat system, such as shown in  FIG. 10 , to fit within the install location, preferably a commercial entranceway. The basket weave pattern formed from the assembled mat system encourage debris removal as patrons walk over the mat system, regardless of their path of travel. Further the spaced apart linear ribs formed in the layers defining gaps  90  permit debris to drop through the gaps  90  where they may be later removed during a floor cleaning process. 
     Additionally, portions of the appended claims refer to different numerical ribs. For further description thereof, it is shown in  FIG. 2  and  FIG. 3  that a transversely extending first rib  44 A is in the first quadrant  24 . A longitudinally extending second rib  46 B is in the second quadrant  26 . A transversely extending third rib  44 C is in the third quadrant  28 . A longitudinally extending fourth rib  46 D is in the fourth quadrant  30 . Collectively, ribs  44 A,  46 B,  44 C, and  44 D are all formed in the upper first layer  40 . A longitudinally extending fifth rib  50 E is in the first quadrant  24  below the first rib  40 A. A transversely extending sixth rib  48 F is in the second quadrant  26  below the second rib  46 B. A longitudinally extending seventh rib  50 G is in the third quadrant  28  below the third rib  44 C. A transversely extending eighth rib  48 H is in the fourth quadrant  30  below the fourth rib  44 D. Collectively, ribs  50 E,  48 F,  50 G, and  48  H are all formed in the lower second layer  42 . 
     In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. 
     Moreover, the description and illustration of the preferred embodiment of the disclosure are an example and the disclosure is not limited to the exact details shown or described. 
     As depicted in  FIG. 8 , the L-shaped male connector  36 , including first leg  72  and second leg  74 , fits in the complementary L-shaped passageway of female connector  38 . When male connector  36  is connected with female connector  38 , the downwardly facing bottom surface of first leg  72  is flush with the bottom surface  42  of second layer  22 . The upwardly facing top surface of second leg  74  is generally flush with upwardly facing top surface  40  of upper layer  20 . An outer perimeter rib  46 A defines surface  76  and is positioned in gap  80 . Note: the outer perimeter rib  46 A is in the second quadrant  26  and fourth quadrant  30  and an outer perimeter rib  44 A corresponds to the first and third quadrants 
     In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. 
     Moreover, the description and illustration of various embodiments of the disclosure are examples and the disclosure is not limited to the exact details shown or described.