CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims benefit of U.S. Provisional Application Serial No. 61/828,889 filed on May 30, 2013, entitled "Modular Rig Mat System" which is hereby incorporated herein by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] Not applicable.

BACKGROUND

[0003] The disclosure relates generally to rig mat systems for use in supporting equipment and personnel of an industrial operation. More particularly, the disclosure relates to rig mat systems for supporting equipment and personnel on hydrocarbon drilling rigs.

[0004] Rig mats are found in many industrial operations (e.g., drilling rig, construction site, etc.) and are often configured to support and distribute loads provided by the weight of equipment, machinery and personnel of the operation. Rig mat designs encompass many different styles and configurations. For instance, rig mats include plastic mats, hollow rig matting systems, access mats, rubber mats and steel frame mats. Steel frame mats may include a plurality of wooden beams supported by a steel frame. In this arrangement, the load (e.g., weight of industrial equipment) acts on the wooden beams, which are configured to transfer and share the bridge load with the steel frame.

BRIEF SUMMARY OF SOME OF THE EMBODIMENTS

[0005] In an embodiment, a mat assembly includes a beam including a first billet comprising a first stack of adjacently adhered wooden boards, wherein a plurality of the boards of the first stack comprise a groove extending into a first face of each board, and a second billet comprising a second stack of adjacently adhered wooden boards, wherein a plurality of the boards of the second stack comprise a tongue extending from a first face of each board, wherein the tongues of the second stack extend into and are adhered to the grooves of the first stack. This embodiment may also include a frame disposed about and coupled to the glulam beam. The frame may include two longitudinal channels, two horizontal channels coupled to the two longitudinal channels, forming a rectangular perimeter, an I-beam extending between and coupled to the two horizontal channels, wherein the height of the I-beam is less than the height of the two longitudinal channels. This embodiment may also further include a third billet comprising a third stack of adjacently adhered wooden boards, wherein a plurality of the boards of the third stack comprise a tongue extending from a first face of each board and a groove extending into a second face of each board, and a fourth billet comprising a second stack of adjacently adhered wooden boards, wherein a plurality of the boards of the fourth stack comprise a tongue extending from a first face of each board, wherein the tongues of the fourth stack extend into and are adhered to the grooves of the third stack. This embodiment may also include a plurality of straps extending between the longitudinal channels and coupled to the I-beam. Also, the first plurality of the boards of the first stack may be pressed together at a pressure of at least 125 pounds per square inch.

[0006] In another embodiment, a mat assembly includes a frame including two longitudinal channels, two horizontal channels coupled to the two longitudinal channels, forming a rectangular perimeter and an I-beam extending between and coupled to the two horizontal channels, wherein the height of the I-beam is less than the height of the two longitudinal channels. This embodiment also includes a glued and laminated beam disposed longitudinally between the I-beam and a longitudinal channel. This embodiment may also include a triangular gusset having an aperture extending therethrough and coupled to one horizontal channel and one longitudinal channel. This embodiment may also include a plurality of straps extending between the longitudinal channels and coupled to the I-beam. In this embodiment, the longitudinal channels may intersect the horizontal channels at a plurality of miter joints. Also, a longitudinal channel may have a curved edge with a radius of at least one inch. However, a longitudinal channel may have a curved edge with a radius that is approximately three times the size of the thickness of the longitudinal channel. Further, a longitudinal channel may have a curved edge with a radius that is approximately twice the size of the thickness of the longitudinal channel.

[0007] An embodiment of a mat system includes a plurality of mat assemblies, wherein each mat assembly comprises a plurality of wooden beams coupled to a frame comprising a gusset having an aperture extending therethrough, and a link assembly coupled to the plurality of mat assemblies, wherein the link assembly comprises a plurality of fasteners, wherein the fasteners of the link assembly extend through the gusset of each of the plurality of mat assemblies. In this embodiment, the link assembly may include a link frame having four elongate portions. Also, each elongate portion of the link frame may include an aperture extending therethrough and configured to receive one of the plurality of fasteners. This embodiment may also include a flexible bushing configured to secure the link assembly to a mat assembly. Also, the fasteners may be bolts.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] For a detailed description of the preferred embodiments of the disclosure, reference will now be made to the accompanying drawings in which:

[0009] Figure 1 is a perspective view of an embodiment of a rig mat assembly in accordance with principles disclosed herein;

[0010] Figure 2 is an exploded perspective view of the rig mat assembly of Figure 1 ;

[0011] Figure 3 is a zoomed-in, cross-sectional perspective view of the rig mat assembly of

Figure 1;

[0012] Figure 4A is an exploded perspective view of a glued and laminated (glulam) beam of the rig mat assembly of Figure 1 in accordance with principles disclosed herein;

[0013] Figure 4B is an exploded front view of the glulam beam of Figure 4A;

[0014] Figure 5 is a perspective view of a modular rig mat system in accordance with principles disclosed herein;

[0015] Figure 6A is an exploded perspective view of a link assembly of the modular rig mat system of Figure 5 in accordance with principles disclosed herein;

[0016] Figure 6B is a front view of the link assembly of Figure 6A;

[0017] Figure 6C is a top view of the link assembly of Figure 6A;

[0018] Figure 6D is a bottom view of the link assembly of Figure 6A;

[0019] Figures 7A and 7B are perspective views of a link frame of the link assembly of Figure 7A in accordance with principles disclosed herein; and

[0020] Figure 8 is a zoomed-in, cross-sectional perspective view of the modular rig mat system of Figure 5.

DETAILED DESCRIPTION

[0021] The following discussion is directed to various exemplary embodiments. However, one skilled in the art will understand that the examples disclosed herein have broad application, and that the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment. [0022] Certain terms are used throughout the following description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function. The drawing figures are not necessarily to scale. Certain features and components herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in interest of clarity and conciseness.

[0023] In the following discussion and in the claims, the terms "including" and "comprising" are used in an open-ended fashion, and thus should be interpreted to mean "including, but not limited to... ." Also, the term "couple" or "couples" is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection of the two devices, or through an indirect connection via other intermediate devices, components, and connections. In addition, as used herein, the terms "axial" and "axially" generally mean along or parallel to a central axis (e.g., central axis of a body or a port), while the terms "radial" and "radially" generally mean perpendicular to the given axis. For instance, an axial distance refers to a distance measured along or parallel to the axis, and a radial distance means a distance measured perpendicular to the axis.

[0024] Referring to Figures 1 and 2, an embodiment of a rig mat assembly 10 is shown. In this embodiment, assembly 10 has a central or longitudinal axis 15 and generally comprises a steel frame assembly 100 and a glued and laminated beam (known as a glulam beam in the art) assembly 200. As shown in Figure 2, frame assembly 100 generally includes an outer frame 110, a pair of longitudinal I-beams 130 and a plurality of straps 150.

[0025] Steel frame assembly 100 includes an outer perimeter frame 110 and two I-beams 130. Perimeter frame 110 includes two longitudinal steel channels 112 and two horizontal steel channels 114. Longitudinal channels 112 are welded to horizontal channels 114 at four miter joints 115. Longitudinal channels 112 include an inner surface 112a, an outer surface 112b and a pair of curved edges 112c that extend along the axial length of channels 112. Similarly, horizontal channels 114 include an inner surface 114a, an outer surface 114b and a pair of curved edges 114c that extend along the axial length of channels 114. Curved edges 112c and 114c are configured to facilitate the handling of rig mat assembly 10 via a forklift or other means. In this embodiment, edges 112c and 114c have an easy radius of approximately two or three times the thickness of channels 112 and 114. Also, in this embodiment channels 112 and 114 are formed from tubing and have an approximate thickness of 1/4" to 1/2". In this embodiment, channels 112 have an approximate length of 12' to 40', an approximate flange width of 3" and an approximate height of 3" to 8". Channels 114 have an approximate length of 4' to 12', an approximate width of 3" and an approximate height of 3"-8". Channels 112 and 114 are formed from square tubing that is cut longitudinally. In another embodiment, channels 112 and 114 may be approximately 5/16" thick and have upper and lower curved edges with a radius of approximately 1". Thus, channels 112 and 114 of this embodiment each have a radius equal to approximately three times their thickness. In this embodiment, channels 112 and 114 may be formed from square tubing having approximate dimensions of (e.g., 6"x6") that is cut longitudinally via a water cooled plasma cutter to form two (e.g., 6"x3") channels.

[0026] Referring now to Figures 1-3, perimeter frame 110 also includes a plurality of triangular steel gussets 118 coupled to channels 112 and 114 at joints 115. Each triangular shaped gusset 118 includes has three sides: 118a, 118b and 118c, where sides 118a and 118b are of approximately equal length. In this embodiment, sides 118a and 118b are approximately 12" in length. Also, each gusset 118 includes a centrally disposed circular or oval aperture 119 configured to allow the rig mat assembly 10 to be handled via a 4-way rigging system of a suitable crane or other piece of equipment and also to provide an attachment aperture for the links 350, which lock the rig mats 10, into a modular matrix. In this embodiment, gussets 118 are approximately 1/2" thick and apertures 119 are approximately 4" in diameter. Two gussets 118 are butt welded to one longitudinal channel 112 and one horizontal channel 114 at each joint 115, with two gussets 118 coupled to the pair of curved edges 112c and 114c, as shown in Figure 3.

[0027] Longitudinal beams 130 have an "I" shaped cross-section (i.e., I-beams), a pair of terminal ends 130a, a web 131 having a pair of side surfaces 136, an upper flange 132 and a lower flange 134. In this exemplary embodiment, beams 130 comprise a steel alloy, have a height of approximately 5 1/2" and a width of 5" to 6". However, in other embodiments beams 130 may have dimensions that differ from those of the beams 130 illustrated in Figures 1 and 2. Also, in this embodiment beams 130 weigh approximately 15 pounds per foot. In other embodiments, beams 130 may weigh approximately between 10-30 pounds per foot. Beams 130 are disposed parallel with and offset from axis 15 and extend between horizontal channels 114, with each terminal end of the two beams welded to the channels 114 to secure them in place. Each I-beam 130 also includes a pair of web extensions 131a and 131b, respectively, that extend axially beyond upper and lower flanges 132 and 134. Once, assembled, extensions 131a and 131b extend towards the inner surface 114a of each channel 114, allowing for the welding of each I-beam 130 to channels 114. In this arrangement, beams 130 are configured to transfer and distribute loads applied to the glulam beam assembly to the perimeter frame 110 of the rig mat assembly 10. Beams 130 are also configured to provide clearance for straps 150 to engage upper flange 132 and lower flange 134 of beams 130 and the inner surfaces 112a of longitudinal channels 112, as shown in Figure 1. In order to allow straps 150 to engage beams 130 and channels 112, the height of each beam 130 is at least slightly less than the height of channels 112. In this embodiment, the height of beams 130 is approximately 1/2" less than the height of channels 112. As will be discussed further herein, beams 130 are disposed such that the upper surface of beam assembly 200 is in engagement with the lower horizontal surface of flange 132 and the upper horizontal surface of flange 134 of each I-beam 130.Referring to Figures 2, 4A and 4B, glulam beam assembly 200 generally comprises a central glulam beam 205 and two outer glulam beams 230 and 250.

[0028] In this embodiment, glulam beams 250, 230 and 250 are formed from Douglas-fir. However, in other embodiments beams 250, 230 and 250 may be formed from other types of wood. Each beam has a first longitudinal end (205a, 230a and 250a), a second longitudinal end (205b, 230b and 250b) a first side (205c, 230c and 250c) and a second side (205d, 230d and 250d). Each glulam beam 205, 220 and 230 includes a plurality of rows or boards and columns of laminated wooden boards, called lams, that form billets. This stacked and interlocking arrangement is configured to increase the bridge strength (i.e., resistance to bending or bending strength) of each beam, and thus, the bridge strength of the glulam beam assembly 200 overall. Further, glulam beam assembly 200 is configured to have a bridge strength approximately equal to the strength of frame assembly 100. In this manner, beam assembly 200 is configured to fail in response to an applied load at approximately the same time as frame 100. In other words, the load required to cause structural failure of beam assembly 200 is approximately equal to the load required to cause structural failure of frame assembly 100. Such a feature may act to mitigate any bottlenecks in the strength of rig mat assembly 10 such that the strength of both beam assembly 200 and frame assembly 100 are used efficiently. For instance, stresses applied to assembly 10 will be shared equitably between the beam assembly 200 and frame assembly 100, such that assembly 200 and assembly 100 are configured to fail at a relatively similar stress applied to assembly 10. [0029] Referring specifically to Figures 4A and 4B, central beam 205 is shown. In this embodiment, beam 205 forms a three-dimensional matrix of wooden, finger-jointed beams or lams. Specifically, beam 205 generally includes six columns or billets 210a-210f (Figure 4B), each comprising four rows of lams 211 a-2 l id. The first or upper row 211a of billets 21 Oa-21 Of comprise a first outer lam 212 for billet 210a, four inner lams 214 for billets 210b-210e and a second outer lam 216 for billet 21 Of. Outer lam 212 includes a first or outer face 212a and a second or inner face 212b. Lam 212 further includes a longitudinally extending outer groove 212c proximal first face 212a and a longitudinally extending notch 212d at second face 212b. Inner lams 214 also include a first face 214a and a second face 214b. A tongue 214c extends perpendicularly relative axis 15 from the first face 214a of each lam 214. Also, a groove 214d extends perpendicularly relative axis 15 into the second face 214b of each lam 214. Lam 216 has a first face 216a, a second face 216b, a tongue 216c extending from first face 216a and a groove 216d proximal second face 216b. Each tongue 214c, 216c, is configured to be inserted into and physically engage an adjacently disposed groove (e.g., grooves 212d and 214d). Outer groove or rabbet 212c of lam 212 allows lam 212 to physically engage longitudinal channel 212. Specifically, first face 212a of lam 212 may be inserted into channel 212 to physically engage inner surface 212a of channel 212. Further, groove 212c allows the upper surface of lam 212 to sit substantially flush against channel 112.

[0030] Second row 21 lb and third row 211c of billets 21 Oa-21 Of each include a first outer lam 220 (billet 210a), four inner lams 222 (billets210b-210e) and a second outer lam 224 (billet 21 Of). Outer lam 220 includes a flat first face 220a, a second face 220b and a groove 220c extending into second face 220b. Inner lams 222 each include a first face 222a, a second face 222b, a tongue extending from first face 222a and a groove 222d extending into second face 222b. Outer lams 224 include a first face 224a having a tongue 224c extending therefrom and a flat second face 224b. Thus, similar to first row 211a, lams 220, 222 and 224 are configured to form an interlocking engagement via insertion of tongues 222c and 224c into an adjacently disposed groove (e.g., grooves 220c and 222d). Further, flat face 220a of lam 220 and flat face 224b of lam 224 extend into channels 112 to engage inner surfaces 112a.

[0031] Fourth row 21 Id includes a first outer lam 228 (billet 210a), four inner lams 230 (billets 210b-210e) and a second outer lam 232 (billet 210f). Lams 228, 230 and 232 are configured similarly to lams 212, 214 and 216, respectfully. However, the lams of row 226 are disposed in an inverted manner relative the lams of row 211a. The inversion of the lams comprising fourth row 21 Id allows for the insertion of outer lams 228 and 232 into channels 212 so they may engage inner surfaces 212a of channels 212. The interlocking relationship provided by the engaging tongues and grooves is configured to strengthen rows 21 la-21 Id. For instance, the interlocking relationship of lams 212, 214 and 216 of row 211a may allow loads applied to beam 205 to be distributed across row 211a and to the frame assembly 100.

[0032] In an embodiment, glulam beam 205 is formed by first adhering and pressing four rows of lams (e.g., finger-jointed wooden boards) vertically together, to form four columns or billets (e.g., billets 210a-210f), where each billet comprises four vertically stacked lams (e.g. rows 21 la-21 Id). Adhesive is applied to the upper and lower surfaces of the two middle lams (e.g., lams 220 of billet 210a), while the uppermost lam (e.g., lam 212 of billet 210a) includes adhesive on its lower surface and the lowermost lam (e.g., lam 228 of billet 210a) includes adhesive on its uppermost surface. Next, tongues, grooves and rabbets are formed on the lams of each billet. In an embodiment, the billets comprise billets 210a-210f, and thus, comprise the lams of rows 21 la-21 Id. Following the process of forming billets 21 la-21 If, beam 205 is formed by adhering and pressing each billet horizontally together. In this step, adhesive is applied the two side surfaces of the inner lams (e.g., lams 214, 222 and 230), the second face 212b, 220b, and 228b of lams 212, 220 and 228, respectively, and to the first side surfaces 216a, 224a and 232a of lams 216, 224 and 232, respectfully. In this arrangement, beam 205 includes lams that are adhered vertically and billets adhered horizontally to provide for greater bridge strength.

[0033] In an embodiment, a urethane glue may be used as the adhesive for the step of forming billets 21 la-21 If and the step of adhering each billet 21 la-21 If to one another to form beam 205. In an embodiment, lams are vertically pressed at a pressure of at least 125 pounds per square inch (PSI) to help form billets 21 la-21 If Similarly, in an embodiment, billets 210a-210f are pressed together at a pressure of at least 125 PSI to form beam 205. Glulam beams 230 and 250 are configured similarly to beam 205, as shown in Figure 2. However, beams 230 and 250 each include a pair of chamfers 232 and 252, respectfully, that are disposed at the intersection between each longitudinal end and a side. Specifically, chamfers 232 of beam 230 are disposed between ends 230a, 230b, and side 230c. Chamfers 252 of beam 250 are disposed between ends 250a, 250b, and side 250d. Chamfers 232 and 252 are configured to provide clearance between beams 230, 250, and gussets 118 of frame assembly 100. [0034] A plurality of perpendicularly or horizontally extending grooves or dados extend into the top surface of row 211a. Specifically, in this embodiment a central groove 234 is disposed longitudinally between a pair of outer horizontal grooves 236. However, in other embodiments there may be no central groove 234. An identical set of grooves extend into the bottom surface of fourth row 21 Id in the same manner (not shown). Grooves 234 and 236 are configured to allow steel straps 150 to extend into channels 112, and to allow for their outside surfaces be disposed flush with the top of the glulam beams, as described above. Further, in this embodiment straps 150 are stitch welded to the upper and lower flanges 132 and 134, respectfully of each beam 130 to enhance the structural integrity of mat assembly 10. As discussed above, I-beams 130 physically engage the glulam beams of beam assembly 200. Specifically, after assembly (as shown in Figure 1) side 230d of beam 230 is in physical engagement with side surface 136 of one beam 130 and side 250c of beam 250 is in physical engagement with side surface 136 of the other beam 130. Also, both sides 205c and 205d of beam 205 are in physical engagement with a side surface 136 of each beam 130. In this arrangement, loads applied to beam assembly 200 may be distributed to I-beams 130 and perimeter frame 110 to further strengthen rig mat assembly 10.

[0035] Having described an embodiment of a rig mat assembly 10, embodiments of a rig mat system will now be described. Referring to Figure 5, an embodiment of a rig mat system 300 is shown. In this embodiment, rig mat system 300 includes six rig mat assemblies 10 (shown without beam assemblies 200 in the interest of clarity) coupled to each other via a plurality of link assemblies 350. As will be described further herein, system 300 is configured to allow for flexibility and modularity in tailoring the footprint or square footage offered by the mat system to a particular industrial application. For instance, link system 300 may be used in different applications having different square footage requirements. Further, link system 300 provides for a relatively smooth working surface to increase safety during operation.

[0036] Referring to Figures 6A-6D, 7A and 7B, link assembly 350 generally comprises a link frame 360 and four fastener or bolt assemblies 380. Frame 360 includes a base 362 having four elongate portions 362a-362d. Each elongate portion 362a-362d includes an aperture 364 that extends through the base 362. The four elongate portions 362a-362d allow the link assembly 350 to "link" or couple up to four adjacently disposed rig mat assemblies 10 together, as shown in Figure 5. Frame 360 further includes a tab 366 that extends upward from base 362 and includes an aperture or lifting eye for handling frame 360. While the embodiment of frame 360 shown in Figures 6A-6D includes four elongate portions 362a-362d, in other embodiments the link assembly 350 may include only two elongate portions, thus only providing for the coupling of two rig mat assemblies 10. Also, while this embodiment of link assembly 350 includes four bolt assemblies 380, in other embodiments alternative types of fasteners may be used, such as studs, rivets, nonmetallic fasteners, and others. Some fasteners may include locking nuts for securing the fasteners to the link assembly 350 while others may not include a locking nut for securing.

[0037] In this embodiment, each bolt assembly 380 includes a fastener or threaded bolt 382, a base pedestal 384, a bushing 386, a compression plate 388, a washer 390 and a locking nut 392. Threaded bolt 382 that is inserted upward and threaded through apertures 364 of frame 360. Once threaded through frame 360 (as shown in Figure 6B), bolts 382 are welded to the base 362 of frame 360 to secure them into place. However, in other embodiments, bolts 382 may be coupled to the frame 360 in some other manner, or they may only be threaded into frame 360 and not fixed thereto.

[0038] Referring now to Figures 6 A and 8, pedestal 384 is configured to fit within the aperture 119 of gusset 118, thus acting as a floor that fits flush against the upper surface of the bottom gusset 118. Pedestal 384 is formed from rigid steel plate and includes an aperture to allow the passage of bolt 382 therethrough. Bushing 386, having a hemispherical upper surface and a flat lower surface, is disposed adjacent pedestal 384 and is configured to radially expand upon the securing of locking nut 392 on bolt 382, thereby securing link assembly 350 to the bottom gusset 118 of the rig mat assembly 10. Also, the pliability of bushing 386 allows adjacent rig mat assemblies 10 coupled to link assembly 350 to flex. For instance, adjacent mat assemblies 10 may flex when positioned over relatively uneven terrain. In this embodiment, bushing 386 is formed from polyurethane but in other embodiments the bushing may be formed from other flexible materials. The compression plate 388 having an aperture is disposed over the bushing 386. In this embodiment, plate 388 comprises steel and has a diameter slightly smaller than pedestal 384, allowing plate 388 to pass through aperture 119 of the bottom gusset 118. Last, washer 390 and locking nut 392 are disposed over the compression plate. In this embodiment, washer 390 is a small grade 8 washer and nut 392 is a locking nut provided by Nylok®.

[0039] While embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the scope or teachings herein. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the systems, apparatus, and processes described herein are possible and are within the scope of the disclosure. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims. Unless expressly stated otherwise, the steps in a method claim may be performed in any order. The recitation of identifiers such as (a), (b), (c) or (1), (2), (3) before steps in a method claim are not intended to and do not specify a particular order to the steps, but rather are used to simply subsequent reference to such steps.