Patent ID: 12240145

DETAILED DESCRIPTION

FIGS.1-51depict the preferred embodiments of articulating composite surface covering mats (herein “mats”) and a method of making mats.

Referring toFIG.1-8, a first embodiment of mat is indicated generally at10. The mat10includes multiple irregularly shaped units12. By the term “irregularly shaped” it is meant that the peripheral side of the unit12appears jagged or roughhewn, or comprises complex curves, and is not a straight line or a simple curve, e.g., a circular arc. However, it should be understood that an irregularly shaped side might comprise a multiplicity of straight-line segments angled with respect to each other, such that the general appearance of the side is irregular. Optionally, one or more portions of sides could consist of or include a straight segment or a regular geometric curve.

All of the units12are at least partially embedded horizontally with at least one section of geogrid14. The geogrid14provides a flexible connection between the individual units12forming the mat10. The mat10is relatively thin and flexible, is of a generally consistent thickness, and can perform as a structurally sound protective shell over stabilized soil or substrate S. In use, multiple mats10are placed next to each other to form an overall surface covering.

The mat10has a generally planar configuration that includes a top surface16, a bottom surface18opposite of the top surface, and a peripheral surface20extending substantially perpendicularly between the top surface and the bottom surface. Likewise, each unit12includes a top surface16A, a bottom surface18A and a peripheral surface20A. The top surface16,16A is preferably irregular, and more preferably has a stone texture or other surface textures to provide a natural appearance (as best seen inFIG.4). Further, the top surface16A can include false joints. Alternatively, for some applications, the top surface16A may be smooth.

The peripheral surface20of the mat10, as viewed from a top plan view, appears irregularly shaped. The peripheral surface20of the mat10generally defines a rectangular or square shape29(seen annotated inFIG.2). However, as will be discussed below, the mat10can have at least three sides. In the preferred embodiment ofFIG.2, there are four total sides including two sides22and two ends24. Each side22,24consists of segments of peripheral surfaces20A of some of the units12located at the exterior of the mat. It is contemplated that the mat10may contain both exterior and interior units12, or may only contain exterior units12(i.e. all units12in the mat10define the peripheral surface20of the mat). The segments of the peripheral surfaces20A of the exterior units12form a center rotation geometry, or “S-curve”.

FIG.2has been annotated to include a peripheral line immediately outside the peripheral surface20of the mat10for purposes of demonstrating the “S-curve” geometry of the sides22,24of the mat. It should be noted that the annotated line is moved outwardly but adjacent to the actual peripheral surface20for purposes of clarity only. The purpose of the annotated line is to show the “S-curve” geometry of the peripheral surface20, prior to surface irregularities being added to the peripheral surface20. That is, the annotated line demonstrates the foundational S-curve geometry of the peripheral surface20of the mat10, before that foundational geometry is obscured visually to the eye by adding irregularities to the peripheral surface20so that each unit12look like natural stone.

By the term “S-curve” it is meant that a first segment21A of each side22,24extending from the centerpoint CP to the endpoint EP would be identical to a second segment21B of each side extending from the centerpoint to the opposite endpoint if the first segment21A was rotated 180-degrees about the centerpoint. The resulting S-curve may be smoothly curved, non-smoothly curved, regular, or irregular.

For purposes of this patent application, the term “S-curve” is used in its broadest sense to mean any shape that is a center 180-degree rotation, other than a straight line. For further disclosure of S-curve geometry, reference is made to U.S. Pat. Nos. 8,336,274 and 8,726,595 to Riccobene, the disclosures of which are entirely incorporated herein.

An S-curve is formed in the peripheral surface20of the mat10at each of the sides22and each of the ends24, as viewed from the top plan view inFIG.2. Preferably, the S-curve formed in the two sides22are substantially identical, such that the S-curve in one side is substantially a translation of the S-curve in the other side. Additionally, preferably the S-curve formed in the two ends24are substantially identical, such that the S-curve at one end is substantially a translation of the S-curve at the other end. The S-curve geometry along each side22and each end24of the mat10facilitates adjacent mats10fitting together (as will be further described with reference toFIGS.9-13), where the adjacent mats are either duplicates of the original mat, or the adjacent mats are non-duplicates of the original mat but have substantially similar S-curve geometry to the original mat. With the S-curve geometry applied over multiple mats10, where the multiple mats are not identical but have substantially similar S-curve geometry at their sides22,24, multiple configurations of mats can be fitted together in multiple layout configurations.

In one embodiment, the mat10has at least three sides22. The peripheral surface20of the mat10defines S-curve geometry on at least two of the three sides. Those at least two sides have a center point CP, and the first segment21A of the side is a 180-rotation of the second segment21B of the side about the center point CP. Further, in an embodiment of mat10having four or more sides22,24, at least two of the sides have the S-curve geometry that allows the mat to mate with an adjacent mat.

Referring back to the preferred embodiment ofFIG.2, while the S-curve geometry is present in each of the sides22and ends24, the peripheral surface20can be irregularly shaped in the plane that is parallel with the top surface16, such that the peripheral surface20substantially follows the S-curve geometry but is not 100% identical to the S-curve geometry when the irregularities are added to the units12. This can be seen inFIG.2where the peripheral surfaces20A of the units12look like natural stone, but still have the foundational S-curve geometry.

Additionally, the peripheral surface20can be irregularly-shaped in the plane extending perpendicularly from the top surface16to the bottom surface18. For example, the peripheral surface20can taper or be non-uniform from the top surface16to the bottom surface18, adding to its irregular shape (best seen inFIGS.4-7). Between these surface irregularities at the peripheral surface20within a single mat10, is and surface irregularities that may be present at the peripheral surface in an adjacent mat, as long as both mats have substantially similar S-curve geometry, the adjacent mats will mate with each other to form a surface covering yet appear seamless without substantial gaps between mats. The term, “without substantial gaps” means no gaps and/or comparatively small gaps that may be filled with sand or mortar, and that are not as large as a single unit, such as between the mating sides of the units10and between individual units12.

As best seen inFIG.8, the embedded geogrid14is preferably smaller in size than the perimeter of the mat10, as long as the geogrid is large enough to have at least one aperture15of the geogrid embedded into each of the perimeter units12of the mat. This allows the perimeter units12to have stone edges that protrude beyond the geogrid14, allowing clear space between projecting portions of exterior units. This also provides a clean perimeter edge of the mat10that facilitates the installation of similarly S-curved shaped adjacent mats to mate with each other without restriction from the embedded geogrid14. Mating of multiple mats10can be seen inFIGS.9-13. The term “mate” is used to refer to the positioning of adjacent mats where adjacent mats fit together like a jigsaw puzzle, but in the state where either gaps28are present between the units, or alternatively where there is contact between adjacent mats10. In the most preferred embodiment, the mating peripheral surfaces20of adjacent mats10should mate with gaps28, but not substantial gaps.

It is contemplated that multiple mats10are provided with a different configuration of irregular units12such that the appearance of the multiple irregular units that are present in a given layout of mats is preferably of different sizes and shapes in plan view, and with a variable gap28A spacing between individual units. The multiple, different mats10having multiple, different individual units12lends to a more natural aesthetic across the layout of mats.

The units12within the mat10are also spaced from each other by the gap is distance28A to allow flexibility between the units and for apertures15in the geogrid14to exist between the units. The individual unit12top surfaces16A are also irregular and designed to mimic natural stone where top surfaces of each unit have a higher height or a lower height than other portions of the top surface of the same unit.

Where the peripheral surface20has a height from the bottom surface18to the top surface16, the S-curve may be defined by the outermost peripheral projection of the surface20in the radial direction from the center of the unit12(where the radial direction is generally parallel to the top surface and the bottom surface of the unit), i.e. the outermost peripheral extent of the surface20as viewed in plan view. The peripheral surface20A of the units12are substantially vertical sides, however the peripheral surface can be rounded, beveled or near vertical-straight from the top surfaces16A of the unit down to the level of the embedded geogrid14. When the peripheral surface20A of these individual units12are coupled with the irregular gap spacing28A between units, the entire installed mat10appears as individual natural stones installed on the substrate S.

Installations of the mats10on slopes will generally be viewed from some distance. Therefore, it is desirable that the individual units12be large enough to see their shape and form from that distance. Units12that are too small in size would appear from a distance as a layer of small aggregate or stone and not necessarily as aesthetically pleasing larger stones. However, due to gravity, larger units12have a tendency to slide down on a slope. The bottom surface18A of one or more units12may include tractive cleats26. The cleats26enable the unit12to penetrate and grip into the soil or substrate S, thereby reducing the tendency for the mats10to slide down the hill. This also puts the geogrid14residing in the gaps28A between the units12directly in touch with the substrate S, which is a desirable position for the geogrid. Additionally, a channel30defines two cleats26that stabilize the unit12with the substrate S.

The embedded geogrid14is preferably a triaxial grid, but other configurations of geogrid are envisioned. For example, a biaxial or rectangular grid, mesh, screen, wire, or any other material that is both semi-rigid and flexible, and defines apertures15therein, are contemplated. Preferably the geogrid14is polypropylene, which has high tensile strength and is generally semi-rigid axially, thereby providing a horizontal and flexible articulating structure through the units. The flexible articulation allows installations of mats10where multiple mats fitted together do not necessarily need to be oriented in one direction or another across a hill or slope. One such geogrid14is commercially available under the trademark TENSAR®. Other types of geogrid14, such as polyethylene or polyester, which are bundled fibers, may be used but are not preferred as these will easily collapse between the units causing the mats to be difficult to handle and install. Not only does the geogrid14provide flexible articulation in the gaps28A between the units12, but it also provides vertical stability between the individual units by restricting their vertical movement due to the geogrid being embedded through the units. Polypropylene geogrid14, while axially semi-rigid, also provides some radial flexibility in gaps28A between the units allowing for minor on-site adjustments to the mat10to aid installation.

Referring toFIGS.41-45, the mat10is shown in 5-directions of articulation: 1)FIG.41shows end-to-end; 2)FIG.42shows side-to-side; 3)FIG.43shows two diagonally opposing corners; 4)FIG.44shows the other two diagonally opposing corners; and 5)FIG.45shows a twist (i.e. a non-45-degree and a non-90-degree articulation), which includes anything that is not purely the articulation directions shown in1) through4). The degree of articulation in any of the 5-directions is dictated by the gap space28A between the units12, the geometry of the individual units12, the material of the geogrid14, and the overall geometry of the mat10. With 5-directions of articulation available to the mat10, the mat is well-suited for an uneven substrate S.

Referring toFIGS.9-13, multiple mats can be arranged in relationship to each other in many configurations to form an overall surface covering. Examples of such configurations are half-bond (FIG.9), basket weave (FIG.10), herringbone (FIG.11), straight bond (FIG.12), offset (FIG.13), and/or combinations of the same, to cover a substrate S with an overall surface covering and to be aesthetically pleasing. Exemplary units10are outlined in bold for purposes of showing their spatial relationship. In the half-bond, one side22A of a first mat10A mates with two half-sides22B,22C of two mats10B,10C. In the basket weave, one side22A of a first mat10A mates with two ends24B,24C of two mats10B,10C. In the herringbone, one end24A of a first mat10A mates with half a side22B of a second mat10B, a first half of a side22A of first mat10A mates with a first half of a side22C of a third mat10C, and a first half of a second side22A′ of mat10A mates with an end24D of a fourth mat10D. In the straight bond, the mats10A and10B are stacked and have the same rotational placement. In the offset, the first mat10A is stacked above two mats10B,10C, but is offset to be adjacent over ¾ of the second mat10B, and ¼ of the third mat10C.

In the finished installation of these five arrangements or combinations of these five arrangements, the individual units12of all mats10are arranged together to visually appear as separate units12that are natural and of irregular thickness. The gaps28between the mats10, and the gaps28A between the units12(as measured at the level of the geogrid) are all irregular, i.e. differing in width.

Additionally, referring back to annotatedFIG.2, the rectangular shape29is defined by the outermost extent of the peripheral surface20of the mat10. It can be seen that the S-curve geometry of each side22,24traverses inside the rectangular box29at intersecting areas31. The intersecting areas31are configured to receive portions of units12of an adjacent mat within the rectangular shape29defined by the original mat. In the most preferred embodiment, the intersecting areas31are not located symmetrically along the sides of the rectangular shape29about the centerpoint CP of the sides22,24. This asymmetric location of the intersecting areas31further obscures the seams of adjacent mats10from view. Additionally, the surface areas of the intersecting areas31are dependent on the S-curve geometry, however in a preferred embodiment, the intersecting areas are in the range of 8% to 20% of the rectangular shape, and more preferably in the range of 10% to 17% of the rectangular shape. Thus, as seen inFIGS.9-13, the resulting appearance of multiple mats10has hidden seams between units10, and is similar to the appearance of a hand placed natural stone.

Referring toFIGS.19-20, multiple mats10are capable of articulation in the 5-directions over natural sloped terrain substrate S. InFIG.20it can be seen that soil, grass, sand, gravel, concrete, glass, grout, plantings, or other materials may be used to fill in the gaps28,28A. In some geographic regions, condensation and moisture is held underneath and between the units10, which can promote plant growth in the gaps28,28A.

Referring toFIG.23, multiple (and preferably all) units12have a raised stacking projection32that is the same height so that each mat10can be stacked substantially level on a pallet. The raised projection32is disguised within the natural looking texture on the top surface16A of the units12so that the projection is not easily discerned, but the projection facilitates even stacking of multiple mats10on top of each other for delivery to the work site.

The mats10arrive at the installation site in a condition to be installed by relatively unskilled workers, in one operation, by directly placing mats onto the soil or substrate S. As seen inFIG.22, the mat10has four corner units12C that define ergonomic handles for users to carry the mat from the pallet to the location of placement on the substrate S. The corner units12C have a protruding geometry such that their relatively slim shape allows them to be easily accessible for manual gripping.

Referring toFIGS.21and25, trimming or cutting the mats10to fit around or against obstacles can be accomplished on site by manually breaking away units12by is using another unit as a fulcrum and fracturing the geogrid14(seeFIG.21).

Alternatively, the geogrid14can be cut between units10with a simple set of hand shears. Either way, trimming away portions of the mats10can allow space for vegetation or other obstacles (FIG.25).

Referring toFIG.24, the bottom surface18A of the unit12may have treads34for gripping the substrate S. Also seen inFIG.24, the unit12may have a bevel36in the range of about 20 to 45-degrees around the perimeter of the bottom surface18A, which provides a smaller footprint of contact of the unit with the substrate S, and provides a larger area for drainage of water between units. The bevel36may extend from the bottom surface18A at about 20 to 45-degrees to about the height of the embedded geogrid14. When the mat10is placed on a substrate S, the bevel and the edge around any of the units12provide a channel for the drainage of water around the units.

Extending from the peripheral surface20vertically downward in the direction of the substrate S, the mat10may have an optional overlap guard38, as seen inFIG.26. The overlap guard38may extend from the top of the bevel36, from the level of the geogrid14, from the outermost extent of the peripheral surface, or anywhere along the peripheral surface. Preferably, the overlap guard38extends from beneath the level of geogrid14. The overlap guard38prevents relative sliding of adjacent units10so that one unit doesn't slide over the top of an adjacent unit in situ.

Another optional feature of the mats10includes spacers (not shown) that are either integrally formed (such as by molding) or removable and located at peripheral surfaces20of exterior units10to facilitate proper alignment between mats or to help prevent mat edges from sliding over adjacent mat edges during installation. Spacers are not required because irregular spacing between mats10also lends to the natural appearance of the finished installation.

As an alternative to manually placing the units10at the installation site, the mats10can incorporate a feed-thru cable-way40which would allow a crane to place the mats (SeeFIG.27). The cable-way40may be molded into the mats, and an embedded cable42can extend through the cable-way for connection to a crane or for connection to other mats. The cable-way40is particularly well suited for larger mats10, or where the mats need to be placed in water, or where the mats are to be placed on a steep slope, or on other difficult terrain.

With these features, the mats10can be placed on steep slopes without sliding down the substrate S. It has been found that the mats10can anchor themselves into the substrate in a 1-to-1 slope. Further, the combination of multiple mats10, and specifically the cooperation of S-curve geometries on the multiple mats, interlockingly links the overall surface covering formed by the multiple mats, so that one mat cannot slide without pulling the rest of the mats with it. In this way, the interlocking cooperation among the mats10keeps the resulting surface covering in place.

However, referring toFIG.28, pins44can be inserted into the geogrid14at the gaps28A to assist in anchoring the mat10to the substrate S. It is contemplated that with the assistance of pins44, the mats can be used on a steep slope up to a near vertical wall. Examples of pins44include nails, staples, hooks, and other known anchoring devices.

It is contemplated that different mats10can be used for commercial/homeowner purposes than for applied engineering purposes. In the smaller commercial or homeowner embodiment, the mat10is preferably about 1.75 square feet in surface area and weighs about 12 pounds, although other surface areas and weights are contemplated. In the applied engineering mat embodiment, the mat10is preferably about 5.6 square feet in surface area and has a weight of about 60 pounds, however other surface areas and weights are contemplated.

In the finished installation, mats10are arranged in combination with each other to form a covering over the substrate S. Once installed, the individual units12contained in the mats10will visually appear as individuals and not as mats. The result is a substrate that looks as if it were covered with individual natural stones of irregular shape and thickness.

Referring toFIGS.14-17, a method of manufacturing the mats10is shown in its most simplified form. The mats10are manufactured upside-down in mold assemblies46. The mold assemblies46consist of a bottom mold48and a top mold50. The bottom mold48has texture and is used to form (face down) the irregular exposed top surface16of the individual units12of the finished mat10.

A pre-sized segment or segments of geogrid14is placed on the bottom mold48in a predetermined position, and then the top mold50, which forms the underside of the units12as well as the optional cleats26, is placed over the bottom mold48. When the top mold50is placed on the bottom mold48, the geogrid25is sandwiched between the top mold and the bottom mold. The filler52, preferably concrete, and more preferably fiber reinforced concrete, is then poured or placed into the mold assembly46through openings54provided in the top mold50. It is contemplated that the filler52can be any sort of wet cast material. Because the geogrid14has open apertures15, the flow of concrete52through the geogrid and into the multiple sections of the bottom mold48is facilitated. Additional concrete52is added until the top mold50is completely filled, thereby embedding the geogrid14. In an embodiment of mat10with cleats26, the protruding cleats are formed at the top surface of the filled concrete. Between the geogrid14reinforcing the concrete52, and the fiber reinforcement within the concrete, the likelihood of flexural, compressive or environmental failure of the units12is minimized.

As seen inFIG.18, the bottom mold48and the top mold50are created with a master mold56, which is the inverse profile of the bottom mold and the top mold. The master mold56may be sculpted with draft to allow easier release of the mold assembly46.

Referring now toFIGS.29-40, a second embodiment of mold assembly is indicated generally at 146, and has a bottom mold148and a top mold150. Like the mold assembly46, the bottom mold148has texture formed into its bottom surface so that it forms (face down) the irregular exposed top surface16of the individual units12of the finished mat10. The bottom mold148and the top mold150are preferably formed of a high-durometer rubber, which renders the mold assembly146flexible and easy to clean, however other materials are contemplated. Preferably, the bottom mold148is a single component or single assembly, and preferably the top mold150is unitarily or integrally formed, which reduces the amount of moving parts that need to be aligned within the mold assembly146.

The bottom mold148has a generally planar bottom surface158, which preferably includes the texture for forming the irregular top surface16of the units12. The bottom mold148also includes multiple transverse walls160extending upwards from the planar bottom surface158forming chambers162. These chambers162are where the units12are molded. The top mold150has a generally planar top surface164, and multiple transverse walls166extending downwards from the planar top surface. The multiple transverse walls166of the top mold150and/or the generally planar top surface164of the top mold define the openings154for receiving the concrete or other filler52into the mold assembly146.

When the top mold150is placed on the bottom mold148, a first portion of the transverse walls160of the bottom mold148are non-sealing walls170A and a first portion of the transverse walls166of the top mold150are non-sealing walls170B that define a cavity172for receiving the geogrid14(seeFIG.30). It is contemplated that the bottom mold148, the top mold150, or a combination of both the bottom and top molds can define the cavity172. Since in use, the non-sealing walls170A,170B have geogrid14sandwiched between them, depending on the filler52used, some seepage may occur at the cavity172, through the geogrid, and through the non-sealing walls. The height of the cavity172is preferably the same or slightly larger than the thickest point on the geogrid14, which is typically located at the node of the geogrid.

A second portion of the transverse walls160of the bottom mold148are sealing walls168A, and a second portion of the transverse walls166of the top mold150are sealing walls168B that, in the absence of the geogrid14therebetween, contact each other and positively seal to prevent seepage of the filler. The sealing walls168A,168B are generally located at the periphery of the mold assembly146, however in an embodiment of the mold where more than one mat10is formed at once, then the sealing walls are also located within the interior of the mold (as will be discussed with detail with respect toFIG.32below).

After the concrete or other filler52is received into the mold assembly146, the mold has a tendency to be pushed apart by the forces exerted by the concrete. A press174is applied to the top planar surface164of the top mold150to aid in maintaining the top mold150on the bottom mold148. The press174is preferably a steel frame176having longitudinal members178that run generally the length of the mold assembly146, and lateral members180connecting the longitudinal members, however any number and arrangement of rigid members forming a frame are contemplated. Both the longitudinal and lateral members178and180preferably abut the planar top surface164of the top mold150to press the top mold against the bottom mold148.

At least two, and preferably four, clamping feet182extend from the frame176downwardly towards the bottom mold148. A clamp184selectively engages the clamping feet182to pin the press174to the bottom mold148. It is contemplated that the clamping feet182are also steel, or any other rigid material, such that the press174forms a frame176that permits stacking of multiple mold assemblies146one on top of the other (SeeFIG.46).

Referring toFIG.32, it can be seen that four mats10are formed in a single mold assembly146at one time, i.e. four mats per cycle on each mold assembly. Although the following description is made with respect to four mats10, any number of mats in multiples of two are contemplated. The transverse walls160in the planar bottom surface158include both sealing walls168A and non-sealing walls170A. The sealing walls168A can be seen at the periphery as having grooves186. Additionally, grooves186are formed into the sealing walls168A that generally bisect the mold longitudinally and laterally. Corresponding positive structures188are formed into the sealing walls168B of the top mold planar surface164(as seen inFIGS.30and35).

It is contemplated that the sealing walls168B of the top mold150and the sealing walls168A of the bottom mold148may have a selectively releasable snap-fit structure190A,190B and190A′ and190B′ as shown inFIGS.33and34. The structures shown inFIGS.33and34are just two examples of releasable snap-fit structures, and other snap-fit structures are contemplated. One such snap-fit structure would be substantially identical to structures190A,190B and190A′,190B′ except that they would be double-sided, having a mirror image along a vertical plane (not shown) ofFIGS.33and34. The sealing wall168A,168B includes bottom transverse wall160and upper transverse wall166that engage each other. Each transverse wall160and166is flexible and is provided with a complimentary shape. The engagement of the sealing wall168A,168B is accomplished by pushing the interlocking components together, and separation of the sealing wall168A,168B is accomplished by elastically deforming the wall. It is also contemplated that incorporation of the snap-fit structures190A,190B and190A′ and190B′ could obviate the use of the press174.

Still referring toFIG.32, and as can be further seen inFIG.38, the upper right mat and the lower left mat to be formed in the mold assembly146are the same mats, albeit rotated 180-degrees. Further, the upper left mat and the lower right mat to be formed in the mold assembly146are the same units, albeit rotated 180-degrees. In other words, the upper right mat to be formed is defined by transverse walls160that are identical, but rotated 180-degrees, to the transverse walls160on the lower left of the is bottom mold148, and the upper left mat to be formed is defined by transverse walls160that are identical, but rotated 180-degrees, to the transverse walls160on the lower right of the bottom mold148. With this particular configuration, the top mold150can be placed onto the bottom mold148in either a 0-degree direction or in a 180-degree rotated direction. This means that in a rectangular mold assembly146, user error is reduced because the rectangular top mold150will only go onto the rectangular bottom mold150in two orientations (0-degrees or 180-degrees) and both of these orientations will result in a sealing of the transverse wall160,166and the mat10being formed.

As seen inFIGS.35and36, the sealing wall168A of the bottom mold planar bottom surface158sealingly engages with corresponding positive structure188of the sealing wall168B of the top mold planar top surface164. In the preferred embodiment, the sealing wall168A is a double-wall with the groove186therebetween. A gasket192may be formed in the exterior double-wall of the sealing wall168A, or alternatively may be formed in the sealing wall168B of the top mold150, to further seal the periphery of the mold assembly146. With the gasket192, leaks outside of the mold assembly146can be prevented or reduced. Gaskets192may also be located at any of the sealing walls168.

Referring toFIG.37, the bottom mold148may include a solid core194, such as a plywood core, that is encapsulated in rubber. The plywood provides rigidity to manufacture larger mats10, and the rubber is easy to clean. Referring now toFIG.38, the master mold156for forming the mold assembly146includes suspension points196for receiving the plywood core. It is also contemplated that branding inserts can be used to incorporate branding198onto the units12(SeeFIG.39).

To manufacture the unit10, the bottom mold148is disposed on a substantially level surface, and the geogrid14is placed horizontally on the bottom mold, and specifically within the cavity172. The geogrid14preferably does not extend over the top of the sealing walls168A. Thereafter, the top mold150is placed over the bottom mold148, thereby sandwiching the geogrid between the top mold and the bottom mold. The sealing walls168B of the top mold150are sealingly engaged to the sealing walls168A of the bottom mold148, preferably by engaging the positive structures188of the top mold into the grooves186in the bottom mold. The snap-fit structure190A,190B may be used to seal the walls168A,168B. Likewise, the non-sealing walls170B of the top mold150are preferably engaged on the geogrid14, which is in turn engaged on the non-sealing walls170A of the bottom mold148.

The press174is positioned over the top of the top mold150, and the clamping feet182are secured with the clamps184. The concrete filler52is then poured or placed into the mold assembly146through the openings154provided in the top mold150. Because the geogrid14has open apertures, the flow of concrete52through the geogrid and into the multiple chambers162of the bottom mold148is facilitated. Additional concrete52is added until the top mold50is completely filled, thereby embedding the geogrid14.

Referring toFIG.40, a flash dislodger200may be inserted into the flash that may result following formation of the mat10. The flash dislodger200may be inserted after molding and initial set, while the unit10is still in the mold assembly146, or alternately after the unit has been removed from the mold assembly. The flash dislodger200is preferably a steel plate having a shape that corresponds with the gaps28A in the mat10. Upon insertion of the flash dislodger200into the formed mat10, the flash dislodger is vibrated, and optionally pressure may be applied, to dislodge the flash and free up the geogrid14between the individual units12. It is contemplated that the flash dislodger200has near vertical edges. It is also contemplated that the flash dislodger200may have saw-toothed edges to facilitate removal of the flash.

The mats10are preferably molded of fiber reinforced concrete, however materials such as ceramics, plastic, natural or synthetic rubber, glass or other suitable material, or combinations thereof are contemplated. To further improve the natural appearance of the mats10, it is desirable to provide variations in the individual units12. In addition to differing the shapes of the units12, dyes and colorants may be added, and the color and quantity of dye may be regulated to produce color variations from unit-to-unit and mat-to-mat. Surface variations in the top surface16and the peripheral surface20from unit-to-unit and mat-to-mat are also desirable.

Referring now toFIGS.47-51, a third embodiment of mold assembly is indicated generally at246, and has a bottom mold248and a top mold250. Like the mold assembly146, the bottom mold248and the top mold250are preferably formed of a high-durometer rubber, which renders the mold assembly246flexible and easy to clean, however other materials are contemplated. It is contemplated that the mold assembly246can incorporate all or some of the features of the mold assembly146to manufacture mats10having all or some or all of the features previously discussed. Further, it is contemplated that the mold assembly246can be used to form mats10having both regularly-shaped units having regular or irregular spacing between the units12and irregularly-shaped units having irregular or regular spacing between the units. The mold assembly246includes a magnetic latch252, which will be described with more particularity below.

The multiple transverse walls266of the top mold250and/or the generally planar top surface264of the top mold define the openings254for receiving the concrete or other filler52into the mold assembly246. After the concrete or other filler52is received into the mold assembly246, the mold assembly has a tendency to be pushed apart by the forces exerted by the filler52. The magnetic latch252maintains the top mold250on the bottom mold248and obviates the need for the press174of the second embodiment. Alternatively, it is contemplated that the magnetic latch252can be used in tandem with the press174.

Specifically, when the top mold250is placed on the bottom mold248, a first is portion of the transverse walls260of the bottom mold248are cavity walls270A and a first portion of the transverse walls266of the top mold250are cavity walls270B that define the cavity272for receiving the geogrid14. It is contemplated that the bottom mold248, the top mold250, or a combination of both the bottom and top molds can define the cavity272. A second portion of the transverse walls260,266form sealing walls268A at the bottom mold248and268B at the top mold250. In the mold assembly246, the sealing walls268A,268B are walls that contact an opposing sealing wall, which are preferably every portion of the transverse walls260,266except for at the location of the cavity272. At the location of the cavity272, the transverse walls260and266do not contact each other.

Since in use, the cavity walls270A,270B have geogrid14sandwiched between them, depending on the filler52used, the cavity walls270A and270B may separate, and some seepage may occur outside of the walls that define the units12. When seepage occurs with materials such as concrete, removal of the subsequent flash from the units12can be burdensome and can require mechanical means to remove the flash, such as with the flash dislodger200. In addition, the sealing walls268A,268B have forces exerted on them by the filler that causes them to want to separate.

The magnetic latch252maintains the sealing walls268A,268B of the transverse walls260,266in contact with each other in a closed position, and maintains the cavity walls270A and270B pressed against the geogrid14. In the most basic form, the magnetic latch252includes at least a first magnet274located on, within or attached to either the top mold250or the bottom mold248, and a second magnet276(including any material that is feromagnetic) that is attracted to the first magnet that is located either on, within, or attached to the other of the top mold or the bottom mold, or alternatively located in such a manner as to magnetically force the top and bottom molds together. In a preferred embodiment, at least a first magnet274is located in one or more locations at the transverse walls266of the top mold250(or alternatively in is one or more locations at the transverse walls260of the bottom mold248), and at least one second magnet276is located in one or more locations at the transverse walls260of the bottom mold248(or alternatively in one or more locations in the transverse walls266of the top mold250). In this preferred embodiment, at least one first magnet274is located in the transverse wall266and at least one second magnet276is located in the transverse wall260to prevent the upwards movement of cavity wall270B away from cavity wall270A. It is preferred that multiple first magnets274are located in a spaced arrangement throughout and along the length of the transverse walls266at the sealing walls268B (i.e. anywhere other than the location of the geogrid14), and multiple second magnets276are located in a spaced arrangement throughout and along the length of the transverse walls260at the sealing walls268A (i.e. anywhere other than the location of the geogrid14). In one preferred embodiment, there are at least three sets of magnets274,276on the transverse walls260,266that define each unit12of the mat10, however the number and the spacing of the magnets274,276may be determined by the size of the mold assembly246, the size of the units12, the strength of the magnets, the strength/rigidity of the molds248,250, and in particular the strength/rigidity of the sealing walls268A,268B.

It is contemplated that the magnetic latch252may be placed anywhere on the top and bottom molds250,248. In the preferred embodiment, the first magnets274are located in multiple locations throughout the length of the transverse walls266of the top mold250(or alternatively in multiple locations throughout the length of the transverse walls260of the bottom mold252). In another embodiment, the first magnets274are located only in the corners of the top mold250or the bottom mold248. Alternatively, instead of having second magnets276located in the bottom mold248, it is contemplated that the bottom mold may be placed on a platform that incorporates ferromagnetic material and the top mold includes a first magnet, such that the top mold is sealed to the bottom mold by the first magnet's attraction to the ferromagnetic platform. Alternatively, the first magnet may be attracted to any other ferromagnetic structure located beneath the bottom mold248. Further still, it is contemplated that first magnets274are located only in the bottom mold248and that the first magnet is attracted to a structure of ferromagnetic material placed over the top of the top mold250.

In the preferred embodiment, the first magnet274and the second magnet276are received into the sealing walls268A,268B of the transverse walls260,266such that they are encapsulated by a layer of the mold. In this configuration, the magnets274,276retain their attraction to each other while being prevented from being pulled out of the transverse walls260,266when the top mold250and the bottom mold248are separated from each other. Other configurations of maintaining the magnets274,276within their respective molds248,250are contemplated, such as a friction fit, reinforcing the mold, molding into a recess of the magnet, and casting the magnet in a suspended state when the mold is cast.

Referring toFIG.49, the first and second magnets274,276comprise one or more magnets that are received into a friction-fit plug278. When the molds248,250are initially cast, a recess280that receives the magnets274,276is formed larger than the magnet size. This provides a clearance between the magnet274,276and the molds248,250.

After the mold248,250is cured, rubber (or other viscous material that cures) forming the friction-fit plug278is deposited into the recess280and the magnets274,276are pressed into the recess. Ribs282may be formed as the rubber flows between the molds248,250and the magnets274,276into side recesses284in the mold and/or magnets. The friction-fit plug278will secure the magnets274,276into the recess280.

With respect to the resulting shape of the units12formed by the mold assembly246having the magnetic latch252, it is contemplated that the molds248,250may be sized and shaped differently to accommodate the magnetic latch252. Specifically, it is contemplated that the angle or profile of the transverse walls260,266may have to be modified from the corresponding transverse walls160,166of the mold assembly146to accommodate the magnetic latch252.

Another feature of the process for the formation of articulating composite surface covering mats10is that a universal geogrid14is used with multiple mold assemblies46,146,246that can define different mats having different shapes and sizes of spaced apart units12. The term “universal geogrid” as used herein is to denote a geogrid that can be used with multiple mold assemblies, where the locations of the nodes and spans (i.e. the positive space) and the locations of the apertures between the nodes and spans (i.e. the negative space) of the geogrid are known relative to the transverse walls266,260of multiple mold assemblies, so that the positive space of the geogrid is received into the cavity272and not over the top of the sealing walls (i.e. so that the positive space does not interfere with the ability of the top mold250to seal with the bottom mold248). In other words, the universal geogrid14can be received in each of the multiple mold assemblies having differing shapes such that the positive space of the universal geogrid14is received between the cavity walls270A,270B of the top mold250and the bottom mold248, and there is only negative space of the geogrid at the engagement of the top mold sealing walls268B to the bottom mold sealing walls268A, i.e the positive space of the universal geogrid does not intersect with the engagement of the upper sealing walls and the bottom sealing walls, except at the cavities272. To accomplish this, the multiple mold assemblies246have the locations of the cavities272for receiving the geogrid at predetermined locations according to the geometry of the universal geogrid14that is to be used with the corresponding multiple mold assemblies.

Many different geogrids14can be used, however one preferred geogrid is rectangular and has a rounded base286and a flat top288(seeFIG.49). Referring to isFIG.51, a most preferred geogrid14is hexagonal and also has the rounded base286and the flat top288. The rounded base286facilitates the placement of the geogrid14into the mold assembly246and also allows the fill material to more completely fill underneath the geogrid. The hexagonal geogrid does not have 90-degree corners, making it easier for the flow of plastic or other material to more easily flow throughout the geogrid during manufacture of the geogrid itself. Further, the flat top288allows a simpler mold assembly246to be built that utilizes a rounded bottom mold248and a flat top mold250. The flat top288also makes the geogrid molding process easier and less expensive.

While particular embodiments of mats10and methods of making same have been described herein, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects as set forth in the following claims.