Patent Publication Number: US-2012024454-A1

Title: Method for fabricating an anti-fatigue mat employing multiple durometer layers

Description:
CROSS REFERENCE TO RELATED PATENT APPLICATIONS 
     This patent application is a continuation of, and claims priority to, the U.S. patent application entitled “Method For Fabricating An Anti-Fatigue Mat Employing Multiple Durometer Layers”, inventor Robert L. McMahan, Ser. No. 12/700,718, filed Feb. 4, 2010, which is a divisional of, and claims priority to, the U.S. patent application entitled “Method and Apparatus For Fabricating An Anti-Fatigue Mat Employing Multiple Durometer Layers”, inventor Robert L. McMahan, Ser. No. 12/016,198, filed Jan. 17, 2008, which is a continuation-in-part of, and claims priority to, the U.S. patent application entitled “Method For Fabricating An Anti-Fatigue Mat”, inventor Robert L. McMahan, Ser. No. 11/537,648, filed Sep. 30, 2006, that is assigned to the same Assignee as the subject patent application. The disclosure of Ser. No. 12/016,198, filed Jan. 17, 2008, is incorporated herein by reference in its entirety and the disclosure of Ser. No. 11/537,648, filed Sep. 30, 2006, is incorporated herein by reference in its entirety. Patent application Ser. No. 12/700,718, filed Feb. 4, 2010, patent application Ser. No. 12/016,198, filed Jan. 17, 2008 and patent application Ser. No. 11/537,648, filed Sep. 30, 2006 are assigned to the same Assignee as the subject patent application. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     The disclosures herein relate generally to mats and more particularly to methodology and apparatus for manufacturing resilient floor mats for reducing user fatigue. 
     BACKGROUND 
     Floor mats have been used for years to provide a cushion for the person standing on the mat. However, fatigue can still result when a person stands on a mat for an extended period of time. Persons who work standing up most of the day, such as cashiers, assembly line operators, people in home or commercial kitchens and many others still experience fatigue after standing on a conventional mat for long periods of time. Often floor mats are provided with non-slip surfaces to lessen slippage and to thus promote safety. 
     Mats of resilient foam are known to reduce user fatigue. Unfortunately however, foam mats have the disadvantage of becoming brittle over time. Conventional foam mats lose their properties as air cells in the mat compress. Moreover, conventional foam mats collect moisture over time. This condition can promote the growth of bacteria and fungus. These undesirable characteristics result in foam mats becoming unsuitable for use as they become older. 
     A mat containing gel sandwiched between various cover layers may address these problems. For example, my U.S. Pat. No. 6,851,141 discloses a resilient mat, one embodiment of which includes a resilient gel inner layer surrounded by a support ring to which an upper cover member and a lower cover member are attached. However, manufacturing such gel-based mats can be difficult. For example, difficulties can be encountered in adhering the upper cover member to the lower cover member. Moreover, undesired wrinkling of the cover members may also be experienced during the manufacture of a gel-based mat. Undesired wrinkling or creasing may also occur when a gel-based mat is stored for shipping in a rolled-up position for an extended period of time and then later unrolled by the user prior to use. 
     What is needed is a method of manufacturing a gel-based mat that addresses one or more of the above described problems. 
     SUMMARY 
     Accordingly, in one embodiment, a method is disclosed for fabricating an anti-fatigue mat. The method includes positioning a first flexible support sheet on a first frame member. The method also includes positioning a second frame member on the first flexible support sheet, the second frame member including an aperture configured to accept heated liquid gel therein. The method further includes dispensing the liquid gel into the aperture in the second frame member so that the liquid gel covers a surface of the first flexible support sheet exposed by the aperture, the gel exhibiting a first predetermined durometer when cooled. The method still further includes positioning a barrier layer on the second frame member and covering the liquid gel, the barrier layer exhibiting a second predetermined durometer. The method also includes cooling the liquid gel to form a gel layer exhibiting the first predetermined durometer. 
     In another embodiment, an anti-fatigue mat is disclosed that includes a first flexible sheet. The mat also includes a resilient gel layer situated on the first flexible sheet and exhibiting a first predetermined durometer. The mat further includes a flexible barrier layer situated on the resilient gel layer, the flexible barrier layer adhering to the resilient gel layer, the flexible barrier layer exhibiting a second predetermined durometer different from the first predetermined durometer of the resilient gel layer. The mat still further includes a second flexible sheet situated on the flexible barrier layer, the flexible barrier layer being moveable with respect to the second flexible sheet. 
     In yet another embodiment, an anti-fatigue mat is disclosed that includes a first flexible sheet. A resilient gel layer is situated on the first flexible sheet and exhibits a first predetermined durometer. The mat also includes a flexible barrier layer situated on the resilient gel layer, the flexible barrier layer adhering to the resilient gel layer. The mat further includes a second flexible sheet situated on the flexible barrier sheet, the flexible barrier sheet being moveable with respect to the second flexible sheet, the second flexible sheet exhibiting a second predetermined durometer different from the first predetermined durometer of the resilient gel layer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The appended drawings illustrate only exemplary embodiments of the invention and therefore do not limit its scope, because the inventive concepts lend themselves to other equally effective embodiments. 
         FIG. 1  shows a portion of a frame assembly used to fabricate an anti-fatigue mat. 
         FIG. 2  shows a portion of the frame assembly with a sheet member in position thereon. 
         FIG. 3  shows a complete frame assembly. 
         FIG. 4  is cross section of the frame assembly of  FIG. 3  taken along section line  4 - 4 . 
         FIG. 5  is a cross section of the frame assembly of  FIG. 3  taken along section line  5 - 5 . 
         FIG. 6  shows the frame assembly of  FIG. 3  at a gel dispensing station. 
         FIG. 7  shows the frame assembly of  FIG. 6  at a gel dispensing station taken along section line  7 - 7 . 
         FIG. 8  shows the frame assembly of  FIG. 6  at a gel dispensing station taken along section line  8 - 8 . 
         FIG. 9  shows a vacuum press station for positioning a flexible sheet on a gel layer in the frame assembly. 
         FIG. 10  shows the vacuum press station of  FIG. 9  after the vacuum press picks up the flexible sheet. 
         FIG. 11  shows the vacuum press station of  FIG. 9  prior to placement of the flexible sheet on the gel layer. 
         FIG. 12  shows the vacuum press station of  FIG. 9  after the head is closed to deposit a flexible sheet on the gel layer in the frame assembly. 
         FIG. 13  shows the vacuum press station of  FIG. 9  when the head is reopened after the deposit of a flexible sheet on the gel layer in the frame assembly. 
         FIG. 14  shows a pre-cooler and main cooler employed in the assembly line used to fabricate a mat using the disclosed methodology. 
         FIG. 15  shows the uncut mat after removal from the frame assembly. 
         FIG. 16A  is a cross section of the uncut mat taken along section line  16 A- 16 A of  FIG. 15  in an embodiment that employs a vinyl strip to promote the adherence of the sheets forming the mat together. 
         FIG. 16B  is a cross section of the uncut mat taken along section line  16 A- 16 A of  FIG. 15  in an embodiment that employs a direct RF weld to connect the sheets forming the mat together. 
         FIG. 17A  is a perspective view of a lower jig used to retain the uncut mat. 
         FIG. 17A  is a cross section of the lower jig of  FIG. 17A  taken along section line  17 B- 17 B that includes a corresponding cross section of the uncut mat that is about to be placed therein. 
         FIG. 18A  is a perspective view of the lower jig with the uncut mat therein shown with a flexible sheet thereon. 
         FIG. 18B  is a cross section of the uncut mat and lower jig taken along section line  18 B- 18 B of  FIG. 18A . 
         FIG. 19A  is a perspective view of the complete jig with the uncut mat therein. 
         FIG. 19B  is a cross section of the complete jig and uncut mat taken along section line  19 B- 19 B of  FIG. 19A . 
         FIG. 20  is a perspective view of the uncut mat after RF welding and removal from the complete jig. 
         FIG. 21  is a representation of the RF welding station used to create the RF weld of  FIG. 20 . 
         FIG. 22  is a representation of a cutting station used in the assembly line to fabricate the mat. 
         FIG. 23  is a perspective view of the mat after cutting the mat at its periphery to remove excess material. 
         FIG. 24A  is a cross section of the trimmed or cut mat of  FIG. 23  taken along section line  24 A- 24 A showing a vinyl layer used to promote connection between the sheets of the mat. 
         FIG. 24B  is a cross section of the trimmed or cut mat of  FIG. 23  taken along section line  24 A- 24 A wherein the sheets of the mat are directly connected together without an intervening vinyl strip. 
         FIG. 25  is a flowchart describing representative steps employed in the disclosed mat fabrication methodology. 
         FIG. 26A  is a cross section of the completed mat showing a layer near the peripheral edge of the sheets of the mat to promote coupling of the sheets together adjacent the peripheral edge. 
         FIG. 26B  is a cross section of the completed mat showing the peripheral edges of the sheet of the mat directly connected to one another. 
         FIG. 26C  is a cross section of the completed mat in the normal use position. 
         FIG. 27A  is a cross section of another embodiment of the disclosed mat that employs an intermediate buffer sheet or layer. 
         FIG. 27B  is a cross section of the mat of  FIG. 27A  together with a cold plate for removing heat during mat fabrication. 
         FIG. 27C  is a cross section of the mat of  FIG. 27A  ready for RF welding. 
         FIG. 27D  is a cross section of the mat of  FIG. 27A  ready for stitching at its peripheral edge. 
         FIG. 27E  is a cross section of the mat of  FIG. 27C  shown in a lower jig of an RF welder. 
         FIG. 27F  is a cross section of the mat of  FIG. 27E  shown position in an RF welder including both a lower jig and an upper jig. 
         FIG. 28A-FIG .  28 G show cross sections of another embodiment of the disclosed mat during fabrication of the mat wherein the mat includes a resilient layer, such as a gel layer, that exhibits a first durometer and a barrier layer that exhibits a second durometer. 
         FIG. 29A-FIG .  29 F show cross sections of another embodiment of the disclosed mat during fabrication of the mat wherein the mat includes a layer, such as a resilient gel layer, that exhibits a first durometer and base sheet that exhibits a second durometer. 
         FIG. 30A-30B  summarize embodiments of the disclosed mat wherein the barrier layer exhibits the second durometer. 
         FIG. 31A-31B  summarize embodiments of the disclosed mat wherein the base sheet exhibits the second durometer. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a portion of a frame assembly  100  that the disclosed methodology employs to fabricate a mat filled with resilient material. In one embodiment, the resilient material is a viscoelastic polymer material such as a synthetic rubber-based gel, a polyurethane-based gel or a silicon-based gel. Frame assembly  100  includes a base frame member  105  that is fabricated of metal such as aluminum for example. Frame assembly  100  also includes a central frame member  110  that is spaced apart from base frame member  105  by spacers  115 . In one embodiment, spacers  115  are fabricated of Teflon™ material. (Teflon is a trademark of DuPont.) Spacers  115  space base frame member  105  and central frame member  110  sufficiently far apart to allow cooling air to flow in the space or channel between these members. In this manner, convective cooling may be provided to a mat fabricated in the frame assembly as later described in more detail. Other cooling apparatus such as liquid cooling apparatus may be used in place of the convective cooling apparatus described above. 
     Central frame member  110  includes registration marks  120  that are used to register a support sheet in a step of the disclosed method. More particularly, turning to  FIG. 2 , a flexible support sheet  205  is registered or aligned with registration marks  120  as shown. In one embodiment, the support sheet  205  forms the side of the mat that faces the user while in use on a floor or other surface. The support sheet  205  contrasts with the base sheet of the mat (not shown in this view), namely the opposite side of the mat which faces the floor or other surface while the mat is in use. In this particular embodiment of the disclosed method, the mat is fabricated in an inverted orientation, namely with the support sheet  205  being placed lowermost in assembly  100  and the base sheet being placed uppermost in the assembly as shown below. However, this order may be reversed if desired. 
     Assembly  100  also includes an aperture frame member  210  having an aperture  215  therein. Aperture frame member  210  is mechanically rotatably coupled to central frame member  110  by a hinge  220  as shown.  FIG. 2  shows assembly  100  in the open position with support sheet  205  registered in position on central frame member  110 . Once support sheet  205  is so registered, aperture frame member  210  is rotated from the open position to the closed position in the direction indicated by arrow  225 . Aperture frame member  210  includes screw holes  230 A that align with threaded screw holes  230 B in central frame member  110  when the aperture frame member  210  is closed. The aperture  215  typically exhibits the same geometry as the desired geometry of the mat being fabricated. In other words, if a rectangular, square, circular or elliptical mat is being fabricated, then aperture  215  exhibits a rectangular, square, circular or elliptical geometry, respectively. The frame members  105 , 110  and  210  may also exhibit the same geometry as aperture  215  although such structures are larger than aperture  215 . While in one embodiment, frame members  105 ,  110  and  210  are fabricated of aluminum, it is also possible to fabricate the frame members from silicon, steel and other durable materials. 
       FIG. 3  shows a frame/mat structure  300  that includes frame assembly  100  in the closed position with support sheet  205  retained therein. With frame assembly  100  so closed, holes  230 A align with screw holes  230 B. Screws  305  are placed in holes  230 A and threaded into corresponding threaded holes  230 B. Screws  305  are tightened into threaded holes  230 B until frame assembly  100  snugly holds support sheet  205  in place. In one embodiment, the four inner edges  210 A,  2108 ,  210 C and  210 D of aperture frame member  210  are angled inward to provide a non-trip feature to the manufactured mat as described below in more detail. In this particular example, an angle of 45 degrees is used for inner edges  210 A,  2108 ,  210 C and  210 D with respect to the major plane of aperture frame member  210 . Angles smaller or larger than 45 degrees may also be used depending on the particular application. Frame assembly  100  together with support sheet  205  forms a gel-receiving cavity  310  as described in more detail below. 
       FIG. 4  is a cross section of the frame/mat structure  300  of  FIG. 3  taken along section line  4 - 4  of  FIG. 3 .  FIG. 4  shows gel-receiving cavity  310  prior to injection of liquid gel therein.  FIG. 5  is another cross section of frame/mat structure  300  of  FIG. 3  except taken along section line  5 - 5  of  FIG. 3 . 
       FIG. 6  shows a work station  600  as a portion of an assembly line  602  in which a mat is fabricated according to the disclosed methodology. The particular view of workstation  600  shown in  FIG. 6  shows frame/mat structure  300  prior to dispensing gel into the gel receiving cavity  310 . Workstation  600  includes a conveyer belt  605  upon which frame/mat structure  300  is situated before liquid gel is dispensed therein. In one embodiment, gel is supplied to a heater  610  that heats the gel to a temperature at which the gel melts and becomes liquid, for example approximately 410° F. in one embodiment. It may also be possible to supply liquid gel to gel receiving cavity  310  without heating the gel if the gel is liquid at ambient or room temperature, for example approximately 75° in one embodiment. In such an embodiment the gel would be designed to cure over time into a gel layer exhibiting a desired durometer or softness. A hose  615  supplies liquid gel from heater  610  to a dispenser head  620  that is situated above conveyer belt  605  on assembly line  602 . To fill cavity  310  with liquid gel, a controller (not shown) instructs conveyer belt  605  to move in the direction indicated by arrows  625 . As cavity  310  passes below dispenser head  620 , dispenser head  620  dispenses heated liquid gel into cavity  620  so that cavity  620  is filled with gel before frame/mat structure  300  exits dispenser head  620 . The controller (not shown) may be programmed to instruct dispenser head  620  to commence dispensing gel when cavity  310  starts to pass below dispensing head  620  and to cease dispensing gel slightly before cavity  310  exits dispensing head  620 . 
       FIG. 7  shows a cross section of frame/mat structure  300  taken along section line  7 - 7  of  FIG. 6  after liquid gel  705  is dispensed into cavity  310 . A criss-cross hatching denotes gel  705  in cavity  310  in  FIG. 7 . The outer edge  705 A of gel layer  705  exhibits an angle of 45 degrees to provide the anti-trip feature mentioned above. As mentioned above, other angles may also produce acceptable results.  FIG. 8  shows a similar cross section of frame/mat structure  300  except this cross section is taken along a different section line  8 - 8  of  FIG. 6 . 
       FIG. 9  shows a perspective view of another portion of the assembly line  602  including a pressing station  905 . This view illustrates pressing station  905  prior to the arrival of sheet/mat structure  300  so that the preparation of a flexible base sheet  920  may be seen. Pressing station  905  includes a registration panel  910  fabricated from a solid material such as wood or metal. Registration panel  910  rotates or swings from side to side about a pivot  915 . An operator or automated equipment places and aligns a base sheet  920  between registration marks  925 . In one embodiment, when fabrication of the mat is complete, base sheet  920  becomes the surface of the mat that faces the floor or other surface on which the mat is used. In one embodiment, base sheet  920  is actually placed on registration panel  910  when registration panel  910  is swung into position on a worktable  930 . Then when registration of base sheet  920  between registration marks  925  is complete, panel  910  is swung from its position atop worktable  930  to a location under vacuum press  935  as shown in  FIG. 9 . 
     Press  935  includes a head  940  with a flat surface  940 A that is capable of holding a sheet of material such as base sheet  920  thereto under vacuum. A vacuum hose  945  connects to press  935  to provide partial vacuum to head  940 . When the registered base sheet  920  is in position below press head  940  as shown in  FIG. 9 , an operator or automated controller rotates press head  940  downward as indicated by arrow  950  until the press head contacts base sheet  920 . Base sheet  920  is then held to press head  940  by the partial vacuum. 
       FIG. 10  shows that base sheet  920  adheres to press head  940  via vacuum action when press  920  is opened as indicated by the direction of arrow  955 . With base sheet  920  so positioned on press head  940 , registration panel  910  is rotated or otherwise moved to table  930  to leave press station  905  clear to receive frame assembly  700 .  FIG. 10  shows registration panel  910  prior to being moved to table  930 . 
       FIG. 11  shows frame/mat structure  300  after being moved into position below press head  940  on assembly line  602 . Frame/mat structure  300  is filled with liquid gel as depicted in  FIGS. 7 and 8 . With frame/mat structure  300  and base sheet  920  so positioned, an operator or programmable controller closes press head  940  onto frame/mat structure  300  as shown in  FIG. 12 . To assure that air bubbles are not trapped in the liquid gel, when press head  940  is closed an operator or programmable controller first applies pressure to one end  940 B of press head  940  and then continues applying pressure across press head  940  until ending with the application of pressure at end  940 C. Press  935  is configured such that press head  940  holds base sheet  920  (not visible in  FIG. 12 ) in registration with support sheet  205  (also not visible in  FIG. 12 ). In other words, press head  935  assures that base sheet  920  aligns with support sheet  205  when press head  935  deposits base sheet  920  on frame/mat structure  300 . 
       FIG. 13  shows press  935  after it has been opened to reveal the frame/mat structure  1300  formed by base sheet  920  and frame/mat structure  300  on which base sheet  920  now rests. Gel layer  705  is shown in dotted lines to indicate that gel layer  705  is below base sheet  920  in this particular view. As seen in  FIG. 13 , base sheet  920  overlaps the edges of gel layer  705  to provide a margin or periphery region which will be attached to a similar margin of support sheet  205 . Press  935  thus functions to place base sheet  920  on gel layer  705  and support sheet  205  therebelow in a vertically aligned manner. Instead of using press  935  for this purpose, it may also be possible to employ a roller to roll on a sheet such as sheet  920 . 
     Returning to  FIG. 10 , it is seen that a pre-cooler  1305  is the next work station of the assembly line  602  after pressing station  905 . After press  935  presses base sheet  920  to frame/mat structure  300  to form frame/mat structure  1300 , frame/mat structure  1300  moves down the assembly line and enters pre-cooler  1305 . In one embodiment, pre-cooler  1305  chills assembly  1300  at an air temperature of approximately 50° F. for approximately 3 minutes. Different temperatures and times can be used depending upon the particular application. 
       FIG. 14  shows frame/mat structure  1300  after an operator or programmed controller moves frame/mat structure  1300  down the assembly line  602  from pre-cooler  1305  to a position under a main cooler  1405  that acts as a main cooling station in the line. In one embodiment, main cooler  1405  includes a pneumatic driven press plate  1410 . A coolant receiving vessel or chamber  1415  is situated on press plate  1410 . In one embodiment, chamber  1415  is filled with ice to maintain the temperature of the press plate at 32 degrees F. In another embodiment, chamber  1415  is replaced with coolant carrying pipes in which a liquid such as alcohol flows to maintain the temperature of press plate  1410  at temperatures lower than 32 degrees F. 
     Before frame/mat structure  1300  enters main cooler  1405 , a controller  1420  instructs press plate  1410  to raise up a sufficient vertical distance to allow frame/mat structure  1300  to enter the space under press plate  1410 . With frame/mat structure  1300  so positioned under main cooler  1405 , controller  1420  instructs press plate  1410  to move downward to apply cooling pressure to frame/mat structure  1300 . In a manner similar to that discussed with reference to  FIG. 12 , press plate  1410  first applies pressure to assembly  1300  at plate end  1410 A and then continues to apply pressure along press plate  1410  along its length until pressure is applied at plate end  1410 B. In one embodiment, frame/mat structure  1300  remains in main cooler  1405  for approximately 2 minutes. Frame/mat structure  1300  may remain in main cooler  1405  for less or more time depending upon the particular application. 
     Frame/mat structure  1300  next exits main cooler  1405 . An operator or machine under program control removes screws  305  (shown above in  FIG. 13 ) from aperture frame member  210 . Aperture frame member  210  is then removed from the remainder of the assembly. This allows the uncut mat formed by support sheet  205 , gel layer  705  and base sheet  920  to be easily removed from central frame member  110 . As seen in  FIG. 15 , since the mat is uncut around its peripheral edges  1500 A,  1500 B,  1500 C and  1500 D, the mat is referred to as uncut mat  1500  at this point in the fabrication process. The rightmost end of uncut mat  1500  is flared open to show gel layer  705  between support sheet  205  and base sheet  920 . It is noted that the mat is still inverted at this point in the fabrication process with support sheet  205  on the bottom and base sheet  920  on top. 
     As part of the process for completing uncut mat  1500 , support sheet  205  and base sheet  920  are connected to one another along the 4 edges  1500 A,  1500 B,  1500 C and  1500 D. In one embodiment, wherein both support sheet  205  and base sheet  920  are fabricated from a resilient material such as vinyl, 4 strips of like material, namely vinyl in this case, are positioned around the periphery of uncut mat  1500 .  FIG. 15  shows these 4 strips as vinyl strips  1505 A,  1505 B,  1505 C and  1505 D which are respectively positioned adjacent edges  1500 A,  1500 B,  1500 C and  1500 D as shown. These vinyl strips are positioned between support sheet  205  and base sheet  920  to facilitate the adherence of support sheet  205  to base sheet  920  along the edges of the mat. The vinyl strips  1500 A- 1500 D may be manually positioned at the locations shown in  FIG. 15 . Alternatively, support sheet  205  may be prefabricated with the vinyl strips already present thereon prior to beginning the fabrication process. In yet another embodiment, base sheet  920  may be prefabricated with the vinyl strips already present thereon prior to the start of the mat fabrication process. In one embodiment, support sheet  205  includes a decorative fabric to improve the appearance of the mat. For example, a synthetic leather material may be bonded to a fabric backing material to form flexible support sheet  205 . When the user stands on the mat, the support sheet  205  is oriented upward so that the decorative fabric is visible to the user. Support sheet  205  may thus provide a cosmetically appealing surface. Flexible base sheet  920  faces downward toward the floor or other usage surface. Base sheet  920  is intended to provide a high friction or non-slip surface so that when placed on the floor, the mat is stable and does not slide during use. One material that may be employed for base sheet  920  is a high friction vinyl or urethane laminated to a fabric backing. 
       FIG. 16A  shows a cross section of uncut mat  1500  taken along section line  16 A- 16 A of  FIG. 15 . Gel layer  705  is sandwiched between support sheet  205  and base sheet  920 . Vinyl strips  1505 C and  1505 A are also visible in the cross section of  FIG. 16A . In a subsequent process step, vinyl strips  1505 A- 1505 D will be melted by a radio frequency (RF) welder to cause support sheet  205  to bond with base sheet  920 . In another approach depicted in  FIG. 16B , the vinyl strips  1505 A- 1505 D are omitted so that peripheral edges of support sheet  205  directly contact the peripheral edges of base sheet  920  prior to placement in the RF welder. In this manner, support sheet  205  and base sheet  920  are directly RF welded together around their respective peripheral edges. In yet another embodiment, the vinyl strips  1505  are replaced with an adhesive, such as hot melt or Epoxy, that causes support sheet  205  to adhere to base sheet  920  around the periphery of uncut mat  1500 . (Epoxy is a trademark of The Dow Chemical Company.) 
     Returning now to  FIG. 16A , vinyl strips  1500 A- 1500 D are positioned as shown and described above. Uncut mat  1500  is next placed in a lower jig  1700  that is illustrated in  FIG. 17A . More particularly, after strip placement, uncut mat  1500  is positioned in lower jig  1700  as indicated in  FIG. 17B .  FIG. 17B  is a cross section of lower jig  1700  and uncut mat  1500  as uncut mat  1500  is oriented for placement in lower jig  1700 . The cross section of lower jig  1700  depicted in  FIG. 17B  is taken along section line  17 B- 17 B of  FIG. 17A . Lower jig  1700  exhibits geometry similar to the geometry of uncut mat  1500 . For example, if mat  1500  is rectangular, square, circular or elliptical, then lower jig  1700  is correspondingly rectangular, square, circular or elliptical. Lower jig  1700  includes a raised portion  1705  that acts as a funnel for RF energy when lower jig  1700  and uncut mat  1500  are later placed in the RF welder.  FIG. 17B  shows uncut mat  1500  in the inverted position and positioned above lower jig  1700  immediately before uncut mat  1500  is placed in lower jig  1700 . It is noted that raised portions  1705  of lower jig  1700  include angled surfaces  1710  extending adjacent the inner perimeter of raised portions  1705 . Raised portions  1710  receive and mate with the angled surface of support sheet  205  as shown. Support sheet  205  follows the angled contours of gel layer  705  and angled surfaces  1710 . 
       FIG. 18A  shows uncut mat  1500  fully placed in lower jig  1700  prior to being moved into the RF welder. The raised portion  1705  of lower jig  1700  is shown in dotted lines below uncut mat  1500 .  FIG. 18B  is a cross section of lower jig  1700  and uncut mat  1500  of  FIG. 18A  taken along section line  18 B- 18 B. 
       FIG. 19A  shows an upper jig  1905  situated above lower jig  1700  and uncut mat  1500  to form a completed jig assembly  1900 .  FIG. 19B  is a cross section of jig assembly  1900  of  FIG. 19A  taken along section line  19 B- 19 B. Upper jig  1905  includes a raised portion  1910  that vertically aligns with raised portion  1705  of lower jig  1700 . With raised portions of upper jig  1905  and lower jig  1700  so aligned, assembly  1900  is placed in an RF welding chamber or station (not shown). When the RF welding station is activated, RF energy is directed between the raised portions  1910  of upper jig  1905  and the raised portions  1705  of lower jig  1700 , thus melting vinyl strips such as strip  1505 C seen in  FIG. 19B . This causes the edges of uncut mat  1500  to be welded together at welded region  1915  as seen in dotted line in  FIG. 19A . The inner boundary  1915 A and outer boundary  1915 B of welded region  1915  are indicated by the dotted lines. After completion of RF welding, upper jig  1905  is raised and the welded uncut mat is removed from lower jig  1700 . Alternatively, the edges of the uncut mat could be welded together without a jig by using ultrasonic welding. Ultrasonic welding may be particularly applicable the larger the size of the mat becomes or for mats with irregular shapes. 
       FIG. 20  is a perspective view of the uncut mat after RF welding. Once RF welding is complete and removed from the jig, the uncut mat is designated as uncut mat  2000 .  FIG. 20  shows the welded region  1915  in dotted lines extending around the peripheral edge of uncut mat  2000 . It is noted that in  FIG. 20 , the mat is no longer in the inverted orientation, but rather is in the normal orientation ready for use.  FIG. 21  is a representation of the RF welder unit or station  2105  in which uncut mat  1500  was welded to become uncut mat  2000 . 
     When RF welding is complete, uncut mat  2000  is moved to a cutting station  2205  shown in  FIG. 22 . In one embodiment, a cut is made around the edge of uncut mat  2000  such that approximately ½ of the width of the welded region  1915  is removed. In other embodiments, more than or less than ½ the width of the welded region may be removed depending upon the particular application.  FIG. 23  shows the resultant cut mat  2300 . The inner boundary  1915 A of welded region  1915  remains and is shown in dotted line. 
       FIG. 24A  shows a cross section of cut mat  2300  taken along section line  24 A- 24 A of  FIG. 23 . More particularly,  FIG. 24A  shows the embodiment wherein vinyl strip  1505  is situated adjacent gel layer  705  and between base sheet  920  and support sheet  205 . In the RF welding process, vinyl strip  1505  melts around the mat&#39;s periphery thus causing the edge of the base sheet  920  and support sheet  205  to adhere to one another.  FIG. 24B  shows the same cross section of cut mat  2300  except in the embodiment wherein placement of vinyl strip  1505  is omitted such that base sheet  920  and support sheet  205  bond directly to one another when placed in the RF welder. In yet another embodiment, an adhesive such as hot melt or Epoxy may be substituted for the vinyl strip  1550  around the periphery of the mat and the RF welding operation may be omitted. In this embodiment, the adhesive seals base sheet  920  to support sheet  205  around the periphery of the mat. 
       FIG. 25  is a flowchart that shows one embodiment of the disclosed methodology for fabricating a resilient mat. In this particular embodiment, the mat is fabricated with an inverted orientation with the support sheet  205  (on which the user stands or otherwise contacts) on the bottom and the base sheet  920  (which faces the floor or other surface) on top in the frame assembly. However, in another embodiment, this order is reversed such that the mat is fabricated in a normal orientation with base sheet  920  on the bottom and the support sheet  205  on the top in the frame assembly. 
     Process flow commences with start block  2500 . The gel is prepared by heating gel to a temperature of approximately 380 degrees F. in one embodiment, as per block  2505 . The aperture frame member  210  is then opened either manually or by a process controller, as per block  2510 . An operator or process controller then registers support sheet  205  on central frame member  110 , as per block  2515 . Once support sheet  205  is registered, aperture frame member  210  is closed. Screws are then used to secure aperture frame member  210  to central frame member  110 , as per block  2520 . Liquid gel  705  is then dispensed into the gel receiving cavity  310  in the frame/mat structure formed by support sheet  205 , central frame member  110 , aperture frame member  210  and base frame member  105 , as per block  2525 . 
     The base sheet  920  is now prepared for positioning on gel layer  705 . Base sheet  920  is registered on registration panel  910 , as per block  2530 . The head  940  of vacuum press  935  then swings downward and contacts base sheet  920 . Vacuum is then applied to head  940  such that head  940  captures base sheet  920  thereon in registered fashion, as per block  2535 . Head  940  with base sheet  920  thereon now swings upward to clear the workspace at vacuum press  935 , as per block  2540 . The assembly formed by base frame member  105 , central frame member  110 , spacers  115 , aperture frame member  210  and gel layer  705  is then moved into position below head  940  of the vacuum press. The head  940  of the vacuum press then swings downward such that base sheet  920  contacts gel layer  705  and aperture frame member  210 , as per block  2555 . The vacuum is released in head  940  and head  940  swings upward leaving base sheet member  920  atop gel layer  705  and vertically aligned with support sheet  205  below, as per block  2560 . In other words, base sheet  920  is registered with respect to support sheet  205  when base sheet  920  is deposited on gel layer  705  by vacuum press  935 . 
     The frame/mat structure formed by base sheet  920 , support sheet  205 , gel layer  705  and the frame members is then moved into pre-cooler  1305  to reduce the temperature of the frame/mat structure, as per block  2565 . The frame/mat structure is then moved along the assembly line to main cooler  1405  to further reduce the temperature of the frame/mat structure, as per block  2570 . At the main cooler, a cold plate contacts the frame/mat structure. First pressure the cold plate applies pressure to one end of the frame/mat structure. The cold plate then applies pressure across the frame/mat structure until reaching the opposite end of the frame/mat structure, as per block  2575 . After cooling, the frame/mat structure is removed from main cooler  1405 , as per block  2580 . Next, screws  305  are removed to allow the opening of aperture frame member  210 , as per block  2585 . The uncut mat is then removed from the frame, as per block  2590 . Vinyl strips  1505  are then applied around the periphery of the uncut mat between support sheet  205  and base sheet  920 , as per block  2591 . Vinyl strips  1505  are positioned adjacent the outermost portion of gel layer  705  near the periphery of the uncut mat. 
     The uncut mat with vinyl strips  1505  is then placed in lower jig  1700 , as per block  2592 . Next, upper jig  1905  is positioned above the uncut mat and lower jig  1700  in preparation for RF welding, as per block  2593 . The jig containing the uncut mat is then moved to RF welder  2105 , as per block  2594 . RF welder  2150  then conducts an RF welding operation that melts the adhesive strips  1505  thus causing support sheet  205  and base sheet  920  to adhere to one another, as per block  2595 . The welded but still uncut mat is then removed from RF welder  2150 , as per block  2596 . Next, the mat is cut in the welded region to trim away superfluous edge material, as per block  2597 . The mat is now complete and the fabrication process ends at end block  2598 . 
     Gel layer  705  provides a very pleasing feel when the user steps on the fully assembled mat. This is especially true when the user steps on the mat without wearing shoes. In one embodiment, the durometer or softness of gel layer  705  should be sufficiently high that it is comfortable for the user to step on the mat and yet sufficiently firm that the user is stable when standing on the mat. Stability here refers to the avoidance of undue lateral motion when standing on the mat. Thus, in one embodiment, the durometer of gel layer  705  is selected to be 50 on the Shore A scale with a tolerance of approximately minus 5 and approximately plus 2. Durometers greater or less than this range can also be used depending on the particular user application. In one embodiment, gel layer  705  may be formed of any synthetic rubber material that includes thermoplastic rubber and mineral oil provided that the durometer of gel layer  205  is as described above. Gel may be stored in semi-solid form prior to placement in heater  610  of  FIG. 6 . In one embodiment, heater  610  provides heated liquid gel to assembly  300 . Gel is provided to assembly  310  in liquid form so that the gel can take the form of gel receiving cavity  310  while the mat is being fabricated. 
     In one embodiment shown in  FIG. 26A , a buffer layer  2605  of polyurethane is sprayed or otherwise applied to the inner side of support sheet  205  that faces gel layer  705 . Another buffer layer  2610  is similarly applied to the inner side of base sheet  920  that faces gel layer  705 . In actual practice, buffer layers  2605  and  2610  are applied to support sheet  205  and base sheet  920  prior to placing these sheets in the frame assembly. Buffer layers  2605  and  2610  perform one or both of the following two functions. Buffer layers  2605  and  2610  prevent mineral oil in gel layer  705  from undesirably migrating from gel layer  705  through the base sheet or support sheet to the exterior of the mat. Buffer layers  2605  and  2610  may also allow gel layer  705  to move within the mat so that, when the mat is rolled up and then later unrolled, a smoother mat is achieved.  FIG. 26B  shows the same buffer layers  2605  and  2610  in the embodiment of the mat wherein the outer edge of support sheet  205  and base sheet  920  are directly RF welded to one another without the use of intermediate vinyl strips  1505 . 
     While  FIG. 26A  shows a cross section of the completed mat  2600  in the inverted orientation in which the mat was fabricated,  FIG. 26C  shows the same mat  2600  that has been rotated 180 degrees to the normal use orientation. In the normal user orientation, base sheet  920  is on the bottom of the mat and support sheet  205  is on the top side of the mat. Angled surface  205 A of support sheet  205  provides the anti-trip feature mentioned above. The angling of surface  205 A makes it less likely that a user will trip on an edge of the mat than if the edge of the mat were perpendicular. 
     In an alternative embodiment, rather than spraying or applying buffer layers  2605  and  2610  as described above, an intermediate sheet or buffer sheet  2705  is positioned on gel layer  705  prior to installation of base sheet  920  on the mat. For example, rather than using press  940  to position base sheet  920  on liquid gel layer  705 , press  940  may position a buffer sheet  2705  on gel layer  705  to form the partially assembled mat  2700  depicted in  FIG. 27A . In one embodiment, buffer sheet  2705  covers gel layer  705 , but does not extend into the margin  2710  adjacent the peripheral edge of the mat. Buffer sheet  2705  is fabricated from a material that slides easily with low friction with respect to base sheet  920  that is placed on buffer sheet  2705  in a subsequent step. However, prior to placement of base sheet  920  on the mat assembly, a cold plate cooler  2715  may be placed on the mat assembly as shown in  FIG. 27B  to cool and remove heat from the mat assembly. Cold plate cooler  2715  may include cooling channels  2720  in which a convective gas coolant such as air or a liquid coolant such as alcohol flows. After cooling the mat assembly to the ambient or room temperature, for example approximately 75° F., the cold plate  2715  is removed from the mat assembly. 
       FIG. 27C  shows mat assembly  2700  after base sheet  920  is situated thereon. Base sheet  920  may be attached to support sheet  205  at margin  2710  directly by RF welding in a manner similar to that depicted in  FIG. 26B  or indirectly via a vinyl strip as shown in  FIG. 26A . Alternatively, the peripheral edge of support sheet  205  may be adhesively coupled to the peripheral edge of base sheet  920  at margin  2710 . In yet another embodiment, the peripheral edge of support sheet  205  may be sewn or stitched to the peripheral edge of base sheet  920  at margin  2710  to connect the two sheets together. As depicted in  FIG. 27C , the mat assembly is still in the inverted position rather that the orientation that the user actually employs. 
       FIG. 27D  shows another embodiment of the mat assembly wherein a sewn peripheral edge holds support sheet  205  and base sheet  920  together to form mat assembly  2750 . In this particular sewn embodiment, a wraparound flap  2725  is positioned at the outer edge of mat assembly  2750  as shown in  FIG. 27D . The mat assembly is then sewn or stitched at margin  2710  through upper flap  2725 A, base sheet  920 , support sheet  205  and lower flap  2725 B to hold the assembly together. 
     As mentioned above, buffer sheet  2705  is fabricated from a material that slides with respect to base sheet  920  that is placed on buffer sheet  2705 . However, buffer sheet  2705  adheres to gel layer  705 . One material that is suitable for buffer sheet  2705  is a fabric such as a cotton or Nylon sheet, for example. Such a material adheres to the gel but allows the base sheet  920  to move with respect to buffer sheet  2705  and the gel layer  705  attached to buffer sheet  2705 . A pocket of air (not shown) may exist between buffer sheet  2705  and base sheet  920 . 
     By allowing base sheet  920  to move with relatively low friction with respect to gel layer  705 , buffer sheet  2705  may prevent wrinkling of the mat assembly when the mat assembly is rolled up for shipment and then unrolled for actual use. Buffer sheet  2705  may also form a barrier that reduces migration of liquid contained in gel layer  705 . For example, if gel layer  705  contains any oils that may separate from the gel over time, then buffer sheet  2705  acts as a barrier that stops or reduces the flow of such liquids to the base sheet  920  of the mat. 
     Positioning buffer sheet  2705  on gel layer  705  as shown in  FIG. 27A  and  FIG. 27B , allows cold plate  2715  to quickly draw heat out of the heated gel layer  705 . This speeds up the manufacturing process. Moreover, buffer sheet  2705  prevents cold plate  2715  from sticking to gel layer  705  which could otherwise damage the mat assembly. In one embodiment, cold plate  2715  is applied to the mat assembly of  FIG. 27B  immediately after application of buffer sheet  2705  to gel layer  705  to remove heat therefrom prior to installing base sheet  920  on the mat assembly. In one embodiment, when heat is so removed from the mat assembly, the previously liquid gel layer  705  becomes semi-solid. 
     As described above with respect to  FIG. 27C , RF welding may be employed to hold mat  2700  together at margin  2710 . More particularly, RF welding forms a weld that bonds support sheet  205  to base sheet  920  at margin  2710 . One RF welding apparatus that may be used to weld these components together is lower jig  1700  of  FIG. 17A ,  17 B and upper jig  1905  of  FIG. 19A ,  19 B.  FIG. 27E-FIG .  27 F, taken together, show an alternative jig for RF welding support sheet  205  to base sheet  920  in the embodiment that includes buffer sheet  2705 . More particularly,  FIG. 27E  shows mat assembly  2700  situated in lower jig  1700 , namely the same lower jig depicted in  FIG. 17A ,  17 B. However,  FIG. 27F  shows mat assembly  2700  with a different upper jig  2760  than upper jig  1905  of  FIG. 19A ,  19 B. Whereas upper jig  1905  includes protrusions  1910  to help direct the RF energy employed in the RF welding process, upper jig  2760  of  FIG. 27F  exhibits a flat surface  2760 A that contacts support sheet  920 . When upper jig  2760  is moved and pressed into contact with mat assembly  2700 , the flat surface  2760 A helps reduce wrinkling in the mat. The raised portions  1705  of lower jig  1700  assure that the RF welding energy flows through support sheet  205  and base sheet  920  at margin  2710  to form the RF weld at that location as desired. 
     It may be desirable to provide mats with different feels to the user for different applications. For example, in some applications it may be desirable for the mat to exhibit a sturdy or more firm feeling to the user standing on the mat. In other applications, it may be desirable to provide the user with a softer feel while standing on the mat.  FIGS. 28A-28G  show process steps in fabricating a mat  2800  that exhibits multiple durometers, namely one layer of the mat exhibits a predetermined durometer and another layer of the mat exhibits a different durometer. Durometer is a measure of the stiffness, resilience or rigidity of a material. The mat fabrication process that  FIGS. 28A-28G  depict is similar to the process that  FIGS. 27A-27F  depict. However, in the process of  FIGS. 28A-28G , buffer sheet  2705  exhibits a durometer different from the durometer of layer  705 . Buffer sheet  2705  is also referred to as a barrier sheet or layer. Like numbers indicate like elements when comparing the structures of  FIG. 28A-28G  with the structures of  FIG. 27A-27F . 
       FIG. 28G  shows completed mat  2800  after removal from jigs  1700 ,  2760  of  FIG. 28F . In  FIG. 28G , completed mat  2800  is rotated into the normal use position, namely with flexible support sheet  205  facing upward toward the user and flexible base sheet  920  facing downward toward the floor or other surface on which the mat is used. Layer  705  exhibits a first durometer (durometer  1 ) and layer  2705  exhibits a second durometer (durometer  2 ) that is different from the first durometer. In one embodiment, layer  2705  exhibits a durometer greater than the durometer of layer  705 . Layer  2705  may be a foam material such as polyurethane foam with a durometer greater than the durometer of layer  705  which may be a gel layer. For example, in one embodiment, foam layer  2705  may exhibit a durometer of approx. 55-approx. 75 on the OO Shore scale while gel layer  705  exhibits a durometer of approx. 15-approx. 30 on the OO Shore scale. These Shore values are provided for purposes of example and should not be regarded as limiting. Other durometer values outside of these ranges may produce acceptable results depending on the particular application. As stated above, in this embodiment, the durometer of buffer or barrier layer  2705  is greater than the durometer of layer  705 . Stated alternatively, the durometer of layer  705  is less than the durometer of layer  2705 . One application of such a mat  2800  wherein layer  705  exhibits a lower durometer is an application where the user standing on the mat prefers a softer feel. In this embodiment, layer  2705  acts as both a barrier layer that prevents migration of oil from gel in layer  705  and also as a second durometer layer.  FIG. 28G  depicts flexible base sheet as the lowermost layer of mat  2800 . When the durometer of buffer layer  2705  is greater than the durometer of layer  705 , this provides the resultant mat  2800  with additional structural integrity. 
     In an alternative embodiment, layer  705  exhibits a durometer greater than the durometer of layer  2705 . Referring again to  FIG. 28G , layer  705  may be a gel layer that exhibits a higher durometer than buffer or barrier layer  2705  below. Buffer layer  2705  may be fabricated of lower durometer polyurethane foam. In this embodiment, layer  705  may exhibit a durometer of approx. 55-approx 75 on the OO Shore scale while layer  2705  exhibits a durometer of approx. 15-approx. 30 on the OO Shore scale. Again, these Shore values are provided for purposes of example and should not be regarded as limiting. Other durometer values outside of these ranges may produce acceptable results depending on the particular application. One application of such a mat  2800  wherein layer  705  exhibits a durometer greater than the durometer of layer  2705  is in styling salons and other areas where high heel shoes may be worn. This mat structure lessens the likelihood of puncture and wear damage from shoes that concentrate weight on a small surface area of the mat. In this embodiment, layer  2705  acts as both a barrier layer that prevents migration of oil from gel in layer  705  and also as a second durometer layer. 
       FIGS. 29A-29E  depict an embodiment of a mat  2900  that includes a buffer or barrier layer  2705  that is separate and distinct from the first and second durometer layers. The mat fabrication steps that  FIGS. 29A-29C  depict are similar to the steps depicted in  FIGS. 27A-27C  with like numbers indicating like elements. As seen in  FIG. 29C , mat  2900  includes a buffer or barrier layer  2705  that separates gel layer  705  from flexible base sheet  920 . Gel layer  705  exhibits a first durometer (durometer  1 ), while flexible base sheet  920  exhibits a second durometer (durometer  2 ).  FIG. 29D  shows mat  2900  rotated to position for use by the user, namely with flexible support sheet  205  facing upward toward the user and flexible base sheet  920  facing downward toward the floor or other base on which the mat is used. In one embodiment, gel layer  705  exhibits a first durometer that that is less than the second durometer of flexible base sheet  920 . For example, in one embodiment, gel layer  705  exhibits a durometer of approx. 15-approx. 30 on the OO Shore scale while flexible base sheet  920  may exhibit a durometer of approx. 55-approx 75 on the OO Shore scale. In another embodiment, gel layer  705  may exhibit a first durometer that is greater than the second durometer of flexible base sheet  920 . For example, in one embodiment, gel layer  705  may exhibit a durometer of approx. 55-approx 75 on the OO Shore scale while flexible base sheet  920  exhibits a durometer of approx. 15-approx. 30 on the OO Shore scale. Again, these durometer values are representative and should not be taking as limiting. 
     In the mat  2900  embodiment depicted in  FIG. 29D , flexible base sheet  920  includes an integral high friction or non-slip external surface that contacts the floor to prevent slippage. For example, flexible base sheet  920  includes rubber-like portions that contact and grip the floor or other surface to lessen or prevent movement on the floor. In this particular embodiment, the high friction or non-slip external surface is an integral part of flexible base sheet  920 . 
       FIG. 29E-29F  depict another embodiment as mat  2900 ′ which is similar to mat  2900  except that mat  2900 ′ includes a layer  2905  of high friction or non-slip material that is separate from, but attached to, flexible base sheet  920 . In other words, in this embodiment, a non-slip surface is not integral to flexible base sheet  920 . Non-slip layer  2905  may be attached to flexible base sheet  920  by adhesive therebetween. In one embodiment shown in  FIG. 29E , after non-slip layer  2905  is attached to flexible base sheet  920 , the mat assembly is then sewn or stitched at margin  2710  through non-slip layer  2905 , upper flap  2725 A, base sheet  920 , support sheet  205  and lower flap  2725 B to hold the assembly together. The resultant mat  2900 ′ is then rotated to the in-use position as shown in  FIG. 29F . 
       FIGS. 30A ,  30 B,  31 A and  31 B summarize mat embodiments described above. More particularly,  FIGS. 30A and 30B  respectively show mats  3001  and  3002  wherein the barrier layer is the second durometer layer.  FIGS. 31A and 31B  respectively show mats  3101  and  3102  wherein the base sheet is the second durometer layer. 
     In more detail,  FIG. 30A  shows mat  3001  wherein barrier layer  2705  is the second durometer layer. Mat  3001  includes support sheet  205 . Mat  3001  also includes a layer  705  that exhibits a first durometer (durometer  1 ) and a barrier layer  2705  that exhibits a second durometer (durometer  2 ) that is different from the first durometer. The second durometer layer  2705  forms a barrier layer that prevents oils, if any, from first durometer layer  705  from reaching base sheet  920 . In one embodiment of mat  3001 , the first durometer layer  705  exhibits a lower durometer than the second durometer barrier layer  2705 . In another embodiment of mat  3001 , the first durometer layer  705  exhibits a higher durometer than the second durometer barrier layer  2705 . In mat  3001  of  FIG. 30A , base sheet  920  includes an integral non-slip surface to prevent or lessen slippage of mat  3001  on a floor or other surface.  FIG. 30B  shows a mat  3002  that is similar to mat  3001  except that mat  3002  includes a non-slip layer  3005  that is separate from base sheet  920  to which it adheres. The layers of mats  3001  and  3002  may be sewn at their margins  2710  or otherwise bonded together as described above. 
       FIG. 31A  shows mat  3101  wherein the base sheet  920  is the second durometer layer. Mat  3101  includes support sheet  205 . Mat  3101  also includes a layer  705  that exhibits a first durometer (durometer  1 ) and a barrier layer  2705 . Mat  3101  further includes base sheet  920  that acts as a second durometer layer that exhibits a durometer that is different from the first durometer of layer  705 . In one embodiment of mat  3101 , the first durometer layer  705  exhibits a lower durometer than the second durometer base sheet  920 . In another embodiment of mat  3101 , the first durometer layer  705  exhibits a higher durometer than the second durometer base sheet  920 . In mat  3101  of  FIG. 31A , base sheet  920  includes an integral non-slip surface to prevent or lessen slippage of mat  3101  on a floor or other surface.  FIG. 31B  shows a mat  3102  that is similar to mat  3101  except that mat  3102  includes a non-slip layer  3105  that is separate from base sheet  920  to which it adheres. The layers of mats  3101  and  3102  may be sewn at their margins  2710  or otherwise bonded together as described above. 
     A methodology for fabricating a resilient mat is thus disclosed in the above description. The fabricated mat is typically comfortable on which to stand or otherwise use to support a part of the body. The layers that exhibit the first and second durometers cooperate to influence the feel of the mat to the user. It should be understood that the steps in the described method need not necessarily be performed in the order described. 
     Modifications and alternative embodiments of this invention will be apparent to those skilled in the art in view of this description of the invention. Accordingly, this description teaches those skilled in the art the manner of carrying out the invention and is to be construed as illustrative only. The forms of the invention shown and described constitute the present embodiments. Persons skilled in the art may make various changes in the shape, size and arrangement of parts. For example, persons skilled in the art may substitute equivalent elements for the elements illustrated and described here. Moreover, persons skilled in the art after having the benefit of this description of the invention may use certain features of the invention independently of the use of other features, without departing from the scope of the invention.