CA2635582A1 - Ground cover mat - Google Patents

Description

"GROUND COVER MAT"
FIELD OF THE INVENTION

The present invention relates to a road or ground cover mat, a system of road or ground cover mats and a method of assembling and disassembling such a system or arrangement of mats.

BACKGROUND OF THE INVENTION

Most known road mats are limited to large square or rectangular mats that are designed to be laid directly onto a ground surface prior to being driven over by vehicles and equipment. These mats see such service in areas where it is prohibitively expensive to develop a full-scale roadway and where access is required and time sensitive, as well as in environmentally sensitive areas where development of a full-scale roadway is simply not feasible due to regulations and/or environmental concerns. These mats are also used where the ground surface is incapable of supporting the weight of a motor vehicle, such as in mud, swamp or muskeg.

These known road mats are limited by their ability to provide some form of highly secure mechanical interlocking mechanism to prevent the shifting of the mats while being traversed by heavy equipment. If the mats shift for any reason and become unhinged, substantial damage may occur to the traversing equipment.
Further, such shifting requires maintenance and realignment of the mats, substantially increasing costs.

Common road mats are mainly large steel and wooden mats that are designed to be laid over the surface to be traversed. In order to reduce axial movement, road mats are commonly manufactured with mating engagements at either end. Such mats generally use a rudimentary L or J shaped reversing or reciprocating style end joint or coupling end that is easily joined upon placement, but provides for very limited and inherently insecure interlocking capability.

FIG. 1 illustrates one such form of engagement wherein a first "L"
shaped appendage extends outwardly and upwardly from a first end and a second "L" shaped appendage extends outwardly and downwardly from a second end of each mat. The engagement of the first "L" shaped appendage with the second "L"
shaped appendage prevents axial movement of connected mats. This engagement works effectively when the underlying surface is firm. However, when the underlying surface is soft, spongy or uneven, the engagement is not effective.
On such surfaces the road mats tend to tip up when weight is exerted upon one end (see FIG. 1). This tipping movement is encountered both as a motor vehicle first drives onto one of the road mats and as the motor vehicle drives off the road mat.
When subjected to this tipping movement, the road mats tend to separate.

United States patent no. 6,652,183 to Stasiewich, et al. partially addresses the separation problem and is directed to a road mat designed to be laid on a ground surface in end to end relation and driven over by a motor vehicle.
The Stasiewich et al. mats are secured together by interlocking the first coupling of one road mat with the second coupling of another, adjacent road mat. The second coupling is adapted to engage the first coupling such that a retaining lip of the

2 second coupling engages a retaining lip of the first coupling to prevent separation (see FIGS. 2a - 2b). Because there is a gap between the couplings' retaining lips, the road mat shown and described in this reference suffers from many of the problems suffered by other conventional mats, including separation of the couplings and creating an uneven surface when weight, such as from a vehicle, is applied to the side of the coupling (see FIG. 2b).

United States patent no. 7,160,055 to Beamish, et al. also partially addresses the separation problem and teaches a more complex form of coupling mechanism that includes a male member and a female member and wherein wherein the first coupling end is a reciprocating mirror image of the second coupling end (see FIG 3a). Beamish, et al. further teaches how a plurality of mats can be connected, side-by-side and end-to-end, to form a "stacked" formation, where both the ends and the sides of adjacent mats line up with each other (see FIG. 3c and Figure 6 of Beamish, et al.). However, this type of arrangement is unstable and if a mat along one end, or along one side, starts to come apart or loose, it has a tendency to "unzip" the rest of the mats along that entire length, or width, of the arrangement of mats (see FIG. 3c); especially if a heavy vehicle starts the unzipping process and happens to move along that unzip line.

The mat designs of Stasiewich et al. and Beamish, et al. are also difficult to separate when rocks, debris and/or ice becomes lodged in the mated couplings or joints (see FIGS. 2c and 3b).

As such, the known road mats have one or more of the following problems: they are restricted in their ability to interlock; they do not provide for an

3 even surface when placed on undulating sub soils; do not create stable arrangements, they do not provide for load dispersal and weight transfer between the structures; they are not very torsion resistant; and they are not designed for ease of installation and removal, i.e., unlocking.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side schematic view of a prior art ground cover mat system, showing two mats coupled to each other and illustrating tipping movement as a motor vehicle first drives onto one end of the first mat;

FIG. 2a is a sectional side view of another prior art ground cover mat, coupled to an adjacent mat;

FIG. 2b is a sectional side view of the coupled prior art ground cover mats of FIG. 2a, illustrating separation of the coupling when weight, such as from a vehicle, is applied to one side of the coupling;

FIG. 2c is a sectional side view of the coupled prior art ground cover mats of FIG. 2a, illustrating how rocks, debris and/or ice may be lodged in the mating couplings;

FIG. 3a is a sectional side view of yet another prior art ground cover mat, shown as becoming uncoupled from an adjacent mat when weight, such as from a vehicle, is applied to one side of the coupling;

FIG. 3b is a sectional side view of the prior art ground cover mats of FIG. 2a, shown in a coupled configuration and illustrating how rocks, debris and/or ice may be lodged in the mating couplings;

4 FIG. 3c is a top view of a plurality of prior art mats arranged in a conventional "stacked" formation;

FIG. 4a is a top / side perspective view of one embodiment of a ground cover mat according to the present invention;

FIG. 4b is side perspective view of the other side of the mat of embodiment of FIG. 4a;

FIG. 4c is a top / side perspective view of the other side of the mat of embodiment of FIG. 4a;

FIG. 4d is a top view of the mat of embodiment of FIG. 4a;

FIG. 5a is a sectional side view of one embodiment of a first side coupling of one mat interlocked with one embodiment of a second side coupling of a second mat;

FIG. 5b is a sectional side view of one embodiment of a first end coupling of one mat interlocked with one embodiment of a second end coupling of a second mat;

FIG. 6a is an end perspective view of two mats of the embodiment of FIG. 4a, with one mat being angularly placed, or connected to, an adjacent mat;
FIG. 6b is a side view of one embodiment of a first side coupling pin;
FIGS. 6c - 6e are sectional side views of the first and second side couplings of the embodiment of FIG. 5a, illustrating angular placement of the first side coupling's pin within the second side coupling's receptacle;

5 FIG. 7a is an side perspective view of an arrangement of mats of the embodiment of FIG. 4a, with one mat being angularly placed, or connected to, an adjacent mat in an adjacent row and, also, to an adjacent mat in the same row;

FIG. 7b is an top perspective view of an arrangement of mats of the embodiment of FIG. 4a, illustrating how the end couplings and side couplings of adjacent mats connect;

FIG. 7c is a top view of an arrangement of mats of the embodiment of FIG. 4a, illustrating the mats being connected in a staggered row configuration; and FIGS. 8a - 8c are top views of an arrangement of mats of the embodiment of FIG. 4a, illustrating the virtual girder system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description are of a preferred embodiment by way of example only and without limitation to the combination of features necessary for carrying the invention into effect. Reference is to be had to the Figures in which identical reference numbers identify similar components. The drawing figures are not necessarily to scale and certain features are shown in schematic form in the interest of clarity and conciseness.

Referring to FIGS. 4a - 8c, one embodiment of a ground cover mat 10 includes a rectangular body 12 having a top surface 12t, a bottom surface 12b, a first end 14, a second end 16, a first side 18 and a second side 20. End coupling

6 means 11 is provided for coupling first end 14 of body 12 to second end 16 of a like body. Side coupling means 13 is provided for coupling first side 18 of body 12 to second side 20 of a like body. Preferably, the top and bottom surfaces 12t, 12b are made from wood. More preferably, the first and second ends 14, 16 and the first and second sides 18,20 are made of steel.

In this embodiment, end coupling means 11 comprises at least one first end coupling 100 positioned at first end 14 of body 12 which is adapted to interlock with a second end coupling 102 at second end 16 of a like body. At least one second end coupling 102 is positioned at second end 16 of body 12 which is adapted to interlock with a first end coupling 100 at first end 14 of a like body. First end coupling 100 and second end coupling 102 will be hereinafter described in relation to FIGS. 4a - 4d and 5b. It will be appreciated, however, that alternative forms of end couplings could be used at first end 14 and second end 16 of body 12.

In this embodiment, side coupling means 13 comprises at least one first side coupling 104 positioned at first side 18 of body 12 which is adapted to interlock with a second side coupling 106 at second side 20 of a like body. At least one second side coupling 106 is positioned at second side 20 of body 12 which is adapted to interlock with a first side coupling 104 at first side 18 of a like body. First side coupling 105 and second side coupling 106 will be hereinafter described in relation to FIGS. 4a - 4d, 5a, and 6a - 6e. It will be appreciated, however, that alternative forms of side couplings could be used at first side 18 and second side 20 of body 12.

7 End couglings:

In this embodiment, first end coupling 100 comprises "L" shaped appendage 22 extending outwardly and downwardly from first end 14 and second end coupling 102 comprises "L" shaped appendage 24 extending outwardly and upwardly from the second end 16 of mat 10. Still referring to FIG. 5b, the engagement of first "L" shaped appendage 22 of a first mat 10a with second "L"
shaped appendage 24 of adjacent mat 10b prevents axial movement of the mats 10a, 10b. The engagement of first "L" shaped appendage 22 of mat 10a with second "L" shaped appendage 24 of adjacent mat 10b will also transfer weight on mat 10a to mat 10b and transfer any upward force, such as during tipping, from mat 10b to mat 10a.

Side couglings:

In this embodiment, first side coupling 104 comprises upwardly directed lug or pin 26 which extends laterally from first side 18 and second side coupling 106 comprises opening 28 providing access to a receptacle 30 extending laterally into second side 20. Interior receptacle 30 is of sufficient dimensions to accept all, or substantially all, of the length of pin 26. In this embodiment first side coupling 104 comprises a pair of upwardly directed pins 26 and the second side coupling 106 comprises a pair of openings 28 providing access to a pair of receptacles 30.

Preferably, the spacing XX between each pair of first side couplings 104 is twice that of the spacing X from a first side couplings 104 to its closest

8 respective end 14, 16 (as the case may be and as more clearly illustrated in FIG.
4d). More preferably, the spacing XX between each pair of second side couplings 106 is twice that of the spacing X from a second side couplings 106 to its closest respective end 14, 16 (as the case may be and also as more clearly illustrated in FIG. 4d). Advantageously, such spacing will allow multiple mats 10 to be connected in a staggered configuration (see FIGS. 7b and 7c) reducing or eliminating the chance that a row of mats will unzip from an arrangement of mats, should one mat start to come loose or disengage along an end or side (as is the case with the prior art mat configurations).

In an alternate embodiment (not shown), the first side coupling 104 is provided in the form of a single upwardly directed lug or pin 26 and the second side coupling 106 is provided in the form of a single opening 28 providing access to a single receptacle 30. In yet an alternate embodiment (also not shown), the first side coupling 104 is provided in the form of three upwardly directed lugs or pins 26 and the second side coupling 106 is provided in the form of three openings 28 providing access to three receptacles 30.

Referring to FIGS. 5a and 6a - 7a upwardly directed pins 26 of a first mat 10a engage or enter receptacle 30 of an adjacent mat 10c, through opening 28.
Receptacle 30 is of sufficient dimensions to allow entry of the pin 26 or substantially all of the pin 26. Advantageously, the pin 26, opening 28 and receptacle 30 allow for easy connection and angular engagement of first mat 10a with adjacent mat 10c.

9 More advantageously, and once the mats 10a, 10c are connected together, the pin 26, opening 28 and receptacle 30 assist to both reduce or prevent lateral axial separation of the first mat 10a from the adjacent mat 10c and to transfer weight, such as that from vehicles, from one mat 10a, 10c to an adjacent mat 10c, 10a.

Preferably, pin 26 has a straight medial portion 26s and an upward curving end portion 26u. More preferably, opening 28 is of sufficient dimensions to allow angular passage or angular placement AP of the pin 26 therethrough, but not so large so as to allow axial, or substantially axial, disengagement of the pin 26 from the receptacle 30 (once adjacent mats are interlocked together. In particular, in this embodiment, the dimensions of the pin 26 (including the upward curving end portion 26u), the opening 28 and receptacle 30, will initially require the first mat 10a to be angled, at an angle A relative to adjacent mat 10c, to allow the upward curving end portion 26u to enter the receptacle 30 through the opening 28 (as more clearly illustrated in FIGS. 6a, 6c - 6e and 7a). Then, once the upward curving end portion 26u has entered the receptacle, the first mat 10a is lowered to a planar, or substantially planar, position (relative to the adjacent mat 10c) and the mats 10a, 10c are axially pushed together to place any remaining straight medial portion 26s (that has not yet entered the receptacle 30) into the receptacle 30. Once this is done, the two mats 10a, 10c are in a "locked" configuration wherein lateral separation of the mats 10a, 10c is reduced or significantly prevented, unless the two mats 10a, 10c become once again angled relative to each other at an angle approximate to A.

Advantageously, when the mats 10a, 10c are connected together at their sides 18, 20, the upward curving end portion 26u of the pin 26 engages upper portion of receptacle 30 above the hole 28 at approximately point P, thereby preventing lateral separation of the first mat 10a from the adjacent mat 10c when the mats are subject to axial separating forces LF (see FIG. 6e).

Since the mats 10a, 10c, during operation are generally expected to remain in a horizontal, or substantially horizontal, position relative to each other (i.e.
co-planar), and since the side couplings 104, 106 are also effective in transferring weight from one mat 10a to an adjacent mat 10c (and vice-versa), this angle A
is typically not approached unless specific action is taken to remove one mat 10a from an adjacent mat 10c (typically requiring explicit and direct lifting of one side of a mat).

Preferably the dimensions of the pin 26, the opening 28 and receptacle 30 are such that the first mat 10a is required to be angled, relative to adjacent mat 10c, approximately 30 to 35 degrees, during angular placement AP, so as to allow entry of the upward curving end portion 26u through the opening and into the receptacle 30. Likewise, an angle of approximately 30 to 35 degrees would be required to disengage side connected mats from each other. Such an angle is not typically observed between adjacent mats (even if the ground itself is uneven or if heavy vehicles drive over the mats), unless specific removal action is taken to disassemble adjacent mats. FIG. 6b illustrates the dimensions of a preferred embodiment of the pin 26.

In another embodiment (not shown), pin 26 is simply a straight horizontal (axial) pin. In such an embodiment, the angle A, required to connect and/or disassemble adjacent mats 10 will likely be smaller than the angle A of a pin having an upward curving portion. However, even such an embodiment will still have effectively transfer weight between adjacent mats (in both directions as described both above and further below) and will provide some resistance to axial disengagement of adjacent mats (especially if the pin 26, opening 28 and receptacle are of close tolerances to provide a friction fit between the pin 26 and the receptacle 30).

Preferably, the pin 26 further comprises a chamfered or tapered end 26t. Advantageously, the tapered end 26t further reduces or eliminates binding when separating the mats 10a, 10c from each other in mud or ice environments.
More preferably, the dimensions of the pin 26 and the opening 28 are of close or tight tolerance so that weight transfer from either mat 10a, 10c (e g. when weight, such as from a vehicle, is applied to one side or the other of the mated side couplings 104, 106) will be efficient and not create a significant uneven surface between the two mats 10a, 10c. Advantageously, a close or tight connection of the pin 26 through the hole 28, also reduces or eliminates the possibility of mud, ice or debris becoming lodged in the couplings 104, 106.

Lifting Points:

In a preferred embodiment, one or more flush mounted lifting points 35 or lifting lugs are provided to facilitate mat 10 pickup and placement.

Advantageously, such mats 10 with lifting points 35 do not require use of an expensive backhoe with a hydraulic "gripping thumb" to manipulate and move the mats; and less expensive forklifts, along with chains or lifting harnesses, can be utilized instead. Preferably, the lifting lugs 35 are rated to 20,000 lbs and are countersunk into the top surface 12t of each mat 10 at or along the mat's center of gravity.

Operation:
The use and operation of the ground cover mats 10 will now be described with reference to FIGS. 4a - 7c. Ground cover mats 10 are designed to be laid on ground surface (not shown) in end to end relation to form a first row 40. In a broad method embodiment, mats 10 in the first row 40 are secured together by interlocking first end coupling 100 of one road mat 10a with second end coupling 102 of adjacent mat 10c (as previously described and as shown in FIG. 5b). A

second row 42 of mats 10 is laid beside the first 40, by angular placement AP
of one side coupling 104, 106 with a respective side coupling 106, 104 of a mat

10 in the first row 40.

In a first method embodiment, a mat 10 in the second row 42 is angled to angle A, the pin(s) 26 on the first side 18 of a mat 10 in the second row 42 are mated to respective opening(s) 28 and receptacle(s) 30 of the second side(s) 20 of an adjacent mat 10 (or a pair of adjacent mats 10a, 10c) in the first row 40, and mat 10 in the second row 42 is angularly placed AP or locked with said mat(s) in the first row 40 (as previously described above); while at the same time interlocking first end coupling 100 of one road mat in the second row 42 with a second end coupling of any adjacent mat in that second row (see FIGS. 5b, 7a and 7b). Subsequent rows, such as a third row 44, are laid beside preceding rows in a similar fashion;
see FIG. 7a which illustrates a mat 10 in a third row 44 positioned adjacent a second row 42 of mats as well as adjacent a mat already present in the third row.

In a second method embodiment (not shown), the mat 10 in the second row 42 is angled to angle A, the opening(s) 28 and receptacle(s) 30 of the second side(s) 20 of mat 10 in the second row 42 are mated to respective pin(s) 26 on the first side 18 of an adjacent mat 10 (or a pair of adjacent mats 10a, 10c) in the first row 40, and mat 10 in the second row 42 is angularly placed AP or locked with said mat(s) in the first row 40 (in a manner similar to that previously described above); while at the same time interlocking first end coupling 100 of one road mat in the second row 42 with a second end coupling 102 of any adjacent mat in that second row. Subsequent rows, such as a third row 44, are laid beside preceding rows in a similar fashion.

Preferably, the multiple mats 10 in each row are connected in a staggered configuration relative to their adjacent rows (see FIGS. 7b and 7c).
Advantageously, such staggered configuration facilitates efficient and effective weight transfer to from one mat 10 to adjacent mats 10, increases the mats 10 overall weight bearing capacity and adds stability to the arrangement or system of interlocked mats 10.

In either method embodiment, disassembly of mats 10 from an arrangement of mats can be accomplished by reversing the steps used to assemble the mats.

Advantageously, the pin(s) 26, the openings, the receptacle(s) 30 and the two method embodiments described above, allow for a row of mats to be assembled and/or disassembled from either the first side 18 or the second side of a row; a feat previously difficult or impossible with prior art ground cover mats.
More advantageously, this two-sided assembly / disassembly allows for an arrangement or system of mats to be moved (over a period of time) along the ground surface by disassembling a row of mats from the "rear" side and re-assembling that row of mats on the "front" side of the arrangement of mats.
Even more advantageously, this allows the use of a finite number of mats to create a moving ground cover mat arrangement that can move along with construction that might span a significant distance over the duration of the construction project (such as oil field pipelining where the construction action moves along the pipeline's proposed route).

Virtual Girder:

In a preferred embodiment, the ground cover mat 10 further comprises three longitudinal support members 50a, 50b, 50c wherein one longitudinal support member 50a is the first side 18, another longitudinal support member 50b is the second side 20 and the remaining longitudinal support member 50c is positioned axially along the longitudinal center of the mat (see FIGS. 4c and 4d).
Preferably, the support members 50a, 50b, 50c are made of steel.

In this embodiment, the ground cover mat 10 further comprises four cross-members 52a, 52b, 52c, 52d, oriented perpendicular to the longitudinal support members 50a, 50b, 50c and wherein one cross member 52a is the first end 14, another cross member 52b is the second end 16 and the remaining two cross members 52c and 52d extend substantially between the paired pins 26 one the first side 18 and their respective corresponding paired receptacles 30 on the second side 20 (see FIG. 4d). Preferably, the cross-members 52a, 52b, 52c, 52d are also made of steel.

Advantageously, in such an arrangement of mats 10, and even if arranged in a "staggered" configuration, the cross-members 52a, 52b, 52c, 52d form a line or "cross-girder" 54 which is continuous in the lateral direction (across such an arrangement of mats 10), across all the connected mats 10 via the pins and receptacles 30 (see FIG. 8a). More advantageously, by comprising at least two cross members (52c and 52d) in the middle portion of the mat 10, the mat 10 is further strengthened so as to prevent or reduce torsion or twisting corner-to-corner.
Even more advantageously, in an arrangement of mats 10, the longitudinal support members 50a, 50b, 50c form a line or "longitudinal-girder" 56 which is continuous in the longitudinal direction (along such an arrangement of mats 10), across all the connected mats 10 via the first and second end couplings 100, 102 (see FIG.
8b).
Together, the cross members 52a, 52b, 52c, 52d and the longitudinal support members 50a, 50b, 50c, in an arrangement of mats 10, create a "virtual girder system" 60 (see FIG. 8c) which adds strength and stability to the entire arrangement.

Those of ordinary skill in the art will appreciate that various modifications to the invention as described herein will be possible without falling outside the scope of the invention.

Claims