Note: Descriptions are shown in the official language in which they were submitted.
CA 02793771 2012-10-29
1 GROUND COVERING SUPPORT STRUCTURE
2
3 TECHNICAL FIELD
4 [0001] The following relates generally to ground covering support structures
and has
particular utility in providing temporary roadways or ground cover for large,
outdoor work areas
6 such as at a well site or a construction site.
7 BACKGROUND
8 [0002] In remote and unstable environments, a stable roadway (or any
roadway) may not
9 exist. Temporary roadways are sometimes assembled by aligning planks, boards
or "mats" along
a desired path. Such temporary roadways or otherwise ground covering support
structures are
11 commonly referred to as access rig or oilfield mats. The mats enable trucks
and other equipment
12 to drive over, store equipment on, or create camp sites on otherwise
unstable land by providing a
13 relatively level and stable surface.
14 [0003] Where many access mats are required to build a temporary roadway, it
can be
onerous to transport and assemble the mats into position. Some prior access
mats such as those
16 shown in U.S. Patent Nos. 4,600,336 to Waller, Jr.; 5,713,695 to Rogers and
U.S. Publication
17 No. 2006/0034654 to Sanders; provide lifting points, however, these lifting
points can either be
18 difficult to access or may provide a trip hazard when protruding from the
upper surface.
19 [0004] Where the lifting points are difficult to access, the
loading/unloading, and moving of
the mats can be hindered, and trip hazards can create unsafe working
environments.
21 [0005] It is therefore an object of the following to obviate or mitigate
the above-mentioned
22 disadvantages.
23 SUMMARY
24 [0006] In one aspect, there is provided a ground covering support structure
comprising a
plurality of longitudinally aligned boards secured to one another using a
plurality of transversely
26 extending rods; and at least one aperture formed in the support structure,
the at least one aperture
27 being aligned with a corresponding one of the rods such that an exposed
portion of the
-1-
22299146.1
CA 02793771 2012-10-29
1 corresponding one of the rods passes through the aperture, each the at least
one aperture
2 containing a retractable lifting link, the retractable lifting link
comprising a lifting eyelet and an
3 elongated slot; wherein the rod passes through the elongate slot to restrict
movement of the link
4 through the aperture.
[0007] In another aspect, there is provided a ground covering support
structure comprising a
6 plurality of longitudinally aligned boards secured to one another using a
plurality of transversely
7 extending rods; and at least one aperture formed in the support structure,
the at least one aperture
8 being aligned with a corresponding one of the rods such that an exposed
portion of the
9 corresponding one of the rods passes through the aperture.
[0008] In yet another aspect, there is provided a ground covering support
structure
11 comprising at least one aperture formed therein, each the at least one
aperture containing a
12 retractable lifting link secured therein by a rod passing therethrough, the
retractable lifting link
13 comprising a lifting eyelet and an elongated slot; wherein the rod passes
through the elongate
14 slot to restrict movement of the link through the aperture.
[0009] In yet another aspect, there is provided a retractable lifting link to
permit lifting a
16 ground covering support structure, the lifting link comprising a lifting
eyelet and an elongated
17 slot to enable the lifting link to be secured within an aperture in the
support structure by a rod
18 passing therethrough such that movement of the lifting link through the
aperture is restricted.
19 [0010] In yet another aspect, there is provided a ground covering support
structure
comprising at least one board constructed of a recycled material such as
beetle kill lumber,
21 plastic or rubber.
22 BRIEF DESCRIPTION OF THE DRAWINGS
23 [00111 An embodiment of the invention will now be described by way of
example only with
24 reference to the appended drawings wherein:
[0012] Figure 1 is a perspective view of an access mat.
-2-
22299146.1
CA 02793771 2012-10-29
1 [0013] Figure 2 is an enlarged perspective view of portion A shown in Figure
1.
2 [0014] Figure 3 is an elevation view of the access mat of Figure 1.
3 [0015] Figure 4 is a plan view of the access mat of Figure 1.
4 [0016] Figure 5 is a pictorial view showing the unloading of the access mat
of Figure 1.
[0017] Figure 6 is an assembly view showing portion A of Figure 1 with a
lifting link.
6 [0018] Figure 7 is a plan view of the lifting link of Figure 6.
7 [0019] Figure 8 is a sectional view along the line B-B in Figure 2.
8 [0020] Figure 9 is the sectional view of Figure 8 assembled with the lifting
link of Figure 7
9 in one configuration.
[0021] Figure 10 is the sectional view of Figure 9 in another configuration.
11 [0022] Figure 11 is a partial plan view of another embodiment.
12 [0023] Figure 12 is a sectional view of portion A along line B-B in yet
another embodiment.
13 [0024] Figure 13 is a partial perspective view of the portion shown in
Figure 12.
14 [0025] Figure 14 is a sectional view of portion A along line B-B in yet
another embodiment.
[0026] Figure 15 is an enlarged portion of the plan view shown in Figure 4.
16 [0027] Figure 16 is an exploded perspective view of a rod.
17 DETAILED DESCRIPTION OF THE DRAWINGS
18 [0028] Referring now to Figure 1, an access mat 10 is constructed from a
series of
19 longitudinally aligned boards 12 attached to each other. It will be
appreciated that the access mat
-3-
22299146.1
CA 02793771 2012-10-29
1 10 may be generally considered as a ground covering support structure that
can be used to create
2 temporary roadways as well as any outdoor work area such as at a well site
or a construction site.
3 [0029] The boards 12 are preferably made from a recycled material such as
beetle kill lumber
4 e.g. - Douglas Fir or pine, which is relatively inexpensive and can be
salvaged and reused for
additional environmental benefits. It will be appreciated that recycled
plastics or rubber
6 materials can also be used, as well as new materials depending on the
application and/or
7 expected environment. The boards 12 are attached by a series of transversely
extending rods 16.
8 In the example shown in Figure 1, four rods 16 are used. Aligned with the
endmost rods 16, a
9 series of apertures 14 are formed in selected boards 12. In the arrangement
shown in Figure 1,
four apertures 14 are formed in the corner portions of the mat 10 such that
the intersection of
11 lines passing diagonally across the mat 10 is approximately in alignment
with the centre of the
12 mat 10. Such an alignment is used to balance lifting loads as will be
explained below.
13 Preferably, the apertures 14 are symmetrically spaced as shown in Figure 1.
14 [0030] The apertures 14 may be cut or mortised through the middle portion
of the boards 12
as shown in Figures 1, 2 and 4 or may be cut or mortised as notches 14a along
one edge of the
16 board 12 as shown in Figure 11. The notches 14a simplify construction of
the selected boards 12
17 by reducing the number of cuts made and/or simplifying the machinery
required to create the
18 apertures 14. The apertures 14 may also comprise an inwardly and downwardly
angled bevel 28
19 cut around the perimeter of the opening on the upper surface of the board
12 as shown in Figures
12 and 13 (referred to hereinafter as aperture 14b). A similar gouge or
partial bevel along one
21 edge of the aperture 14 may also be used.
22 [0031] When aligned, the boards 12 may be secured to each other along their
respective
23 lengths by drilling through the boards and embedding the rods 16. As can be
seen in Figures 15
24 and 16, in one embodiment, the rods 16 are threaded at one end to
accommodate a nut 17 and
link (not shown) and are given a bent portion 19 at the other end. When
assembled, the holes in
26 the board 12 at one end can be countersunk to accommodate the nut 17 and a
routered pocket 21
27 can be cut into the board 12 at the other end such that the bent portion 19
countersinks into the
28 board 12 when the nut 17 is tightened on the rod 16. The bent portion 19
enables the mat 10 to
-4-
22299146.1
CA 02793771 2012-10-29
1 be assembled by tightening at only one end rather than having to tighten at
both ends. Since it is
2 preferable to countersink the nut 17, only having to tighten one end
increases the efficiency of
3 the assembly process. It has been found that 1" rods and up to 1 1/4" holes
provides an adequate
4 fit between the boards 12 and the rod 16.
[0032] The endmost rods 16 are aligned with the apertures 14 such that an
exposed portion
6 18 of the respective rods 16 pass substantially through the centre of the
aperture 14 as shown in
7 Figures 2 and 4. As can be seen in Figure 3, when assembled, the access mat
10 can provide a
8 stable surface atop a region of underlying material 20 such as earth or
stones. The mats 10 can
9 be placed end to end to form a temporary roadway over such underlying
material 20.
[0033] The apertures 14 can be sized such that the exposed portions 18 of the
rods 16
11 provide a set of lifting points. For such an embodiment, the apertures 14
would be sized to
12 accommodate an appropriately sized hook or other attachment mechanism.
13 [0034] In another embodiment illustrated pictorially in Figure 5, a
transport vehicle 23
14 having a crane with lifting cables 25 (or other similar lifting apparatus)
can rely on a series of
retractable lifting links 22 that can be retrieved from the apertures 14 to
hoist the access mat 10.
16 As can be seen in Figure 6, the links 22 can be attached to the mat 10 by
inserting the rods 16
17 through an elongated slot 26 such that the link 22 pulls against the
exposed portion 18 to thereby
18 lift the mat 10. The link 22 also provides a lifting eyelet 24 or other
suitable aperture, hole or
19 slot to accommodate the attachment of a hook or lifting mechanism. The link
22 is also shown
in Figure 7. It can be seen by referring to Figures 7 through 10 that the
elongated slot 26 permits
21 the link 22 to be pulled out from the aperture 14 for lifting, and permits
the link 22 to be hidden
22 within the board 12 when not in use. In this way, when the access mat 10 is
in situ, the link 22
23 does not create a trip hazard. However, the link 22 is readily accessible
when the mat 10 is to be
24 lifted and/or transported.
[0035] It can be appreciated that the apertures 14, 14a, 14b can be sized to
restrict pivotal
26 movement of the links 22 about the rods 16 as shown best in Figures 9 and
10 or may be sized
27 similar to the proportions shown in Figure 6 to permit a predefined amount
of pivotal movement
-5-
22299146.1
CA 02793771 2012-10-29
1 as shown in Figure 14. In order to adjust the amount of pivotal movement
permitted, the rods 16
2 can be realigned towards the upper surface of the mat 10 and the apertures
14b with bevel 28
3 used to provide additional manoeuvrability. The pivotal rotation enables the
link 22 to naturally
4 align with the tension forces in the lifting cables 25 to reduce wear and
stress on the boards 12
when the mat 10 is being lifted. A similar gouge or partial bevel may instead
be provided along
6 only one edge of the aperture 14 so as to provide better access to the link
22.
7 [0036] As noted above, the access mat 10 can be constructed of a recycled
product such as
8 beetle kill lumber such as Douglas fir or pine that has been found to be
capable of withstanding
9 approximately 30,000 lbs or more. Other materials may instead be selected to
accommodate
different loads in different environments. The advantages of using beetle kill
lumber or similar
11 waste products is that the material may be relatively inexpensive to
acquire and provides an
12 environmental benefit. Where the access mats 10 are to be constructed for
temporary use and
13 discarded later, the use of a recycled cost effective material is also
desirable.
14 [0037] As can be seen in Figure 1, a radio frequency identification (RFID)
tag 7 can be
embedded into the access mats 10 in a routered pocket 8 to enable the access
mats 10 to be
16 included in an inventory system (not shown). The RFID tags 7 provide an
owner and/or renter of
17 the mats 10 with a unique identification serial number for each individual
mat 10. Where many
18 mats 10 are being used and/or rented, this enables the tracking and
reconciliation of the
19 inventory. In this way, e.g., as mats 10 are unloaded off of the vehicle
23, an RFID reader (not
shown) can record each mat 10 that is placed at that particular job site.
Therefore, inventory
21 associated with that job site can be recorded for later referral, billing,
etc. As mats 10 are later
22 loaded back onto the vehicle 23, they can again be scanned or read to
ensure that all mats 10 are
23 accounted for. It will be appreciated that the RFID tags 7 can be active or
passive and other
24 tracking devices such as barcodes (not shown) could similarly be used.
Although the RFID tag 7
is shown as being embedded on the side of the mat 10, it will be appreciated
that it may be
26 embedded on the top, bottom, end etc. Preferably, the RFID tags 7 are
sealed in the pocket 8
27 using a suitable adhesive or epoxy for protection, waterproofing and to not
degrade the signals.
-6-
22299146.1
CA 02793771 2012-10-29
1 [0038] To assemble the access mat 10, each board 12 is drilled to
accommodate the rods 16
2 whereby one hole is drilled in each board 12 for each rod 16. A drilling
station can be used with
3 a drill press for each hole to ensure a consistent spacing between the
holes. The holes for the
4 appropriate board 12 are then counter sunk to accommodate the nuts 17 at one
end of the mat and
the board 12 for the other end of the mat 10 is routered to provide the
appropriate number of
6 pockets 21. The appropriate selection of boards 12 are then cut or mortised
to form a series of
7 apertures 14, which may be notches 14a or complete passages and may include
a bevel 28 or
8 gouge for accessing the link 22.
9 [0039] The boards 12 consequently comprise a series of holes of which one
hole is aligned
substantially centrally across each aperture 14 as shown in Figure 2. Also, as
shown in Figures
11 15 and 16, the appropriate board 12 includes countersunk holes and the
appropriate board
12 includes routered pockets 21 for containing the bent portions 19. It will
be appreciated that there
13 may be any number of apertures 14 and any number of rods 16 with
corresponding countersinks
14 and pockets 21. However, the symmetrical arrangement shown in Figure 1 is
preferred.
[0040] In each aperture 14, a link 22 may then be placed with the lifting
eyelets 24 facing up
16 such that when the rods 16 are embedded or fed into the boards 12, the
exposed portions 18 of
17 each pass through the respective elongated slots 26. The rods 16 are fed
through the boards 12
18 by inserting the threaded end into the pocketed board and then through the
remaining board until
19 it emerges at the other side of the mat 10 where the nut 17 is tightened
thus countersinking the
rod 16 at both ends. As the rods 16 are embedded, the boards 12 are preferably
secured against
21 each other longitudinally and a suitable adhesive may be used to strengthen
the assembly if
22 desired. When assembled, the boards 12 may be trimmed at each end to
provide flush end faces
23 to accommodate end-to-end alignment.
24 [0041] The mat 10 may be lifted onto the vehicle 23 as shown in Figure 5,
by first retrieving
each link 22 from the respective aperture 14 and attaching the corresponding
lifting cable 25
26 using the exposed lifting eyelet 24 when in the position shown in Figure 6,
Figure 9 or Figure 14.
27 The link 22 may be retrieved using a screwdriver, similar prying bar or
even pulled out by the
28 operator depending on the nature and size of the aperture 14. For example,
the aperture 14b
-7-
22299146.1
CA 02793771 2012-10-29
1 having a bevel 28 or similar gouge along one side may better accommodate a
prying bar or
2 screwdriver by offering a clear angle towards the lifting eyelet 24. In
another example, the
3 aperture 14 may be sized to provide enough peripheral room to enable the
operator to grip the
4 link 22.
[00421 Once each link 22 has been retrieved and attached to the lifting cables
25, the vehicle
6 23 may then lift the mat 10 onto a flatbed or other surface for transport.
When the cables 25 are
7 detached, the links 22 simply slide into the apertures 14 leaving a
substantially flush upper
8 surface enabling several mats 10 to be stacked atop each other without
becoming unstable.
9 When unloading, a similar process can be followed.
[00431 It can therefore be seen that the link 22 can be hidden when not in use
and readily
11 retrieved for lifting and/or transportation. The link 22 does not present a
trip hazard yet greatly
12 aids in the handling of the access mats 10. It will be appreciated that
although preferably used
13 with a set of corresponding links 22, the access mats 10 as shown in
Figures 1, 3 and 4 may also
14 be used without the links 22 if so desired. It will also be appreciated
that the boards 12 may also
be used with any suitable material that can withstand the anticipated weight
of the machinery
16 expected to cross the temporary pathway or roadway.
17 100441 Although the invention has been described with reference to certain
specific
18 embodiments, various modifications thereof will be apparent to those
skilled in the art without
19 departing from the spirit and scope of the invention as outlined in the
claims appended hereto.
-8-
22299146.1
