Board Mat Construction

1. Field of the Invention

This invention relates to a mat to be constructed of wood or wood products and to be used in vertically and horizontally lapped relation in order to form a roadway or platform mat upon soft ground.

2. Description of Related Art

Various different forms of board mat constructions heretofore have been provided such as those disclosed in U.S. Pat. Nos.: 1,970,037, 2,639,650, 2,652,753, 2,819,026, 2,912,909, 4,289,420, 4,462,712 and 4,600,336. However, these various different forms of mat constructions, in many instances, do not provide sufficient ground traction between the mat constructions and the underlying ground surface and between the upper surface of the mat construction and a vehicle moving thereover. Furthermore, these previously known mat constructions may not be readily mass produced at low cost and the spacing of multiple transverse members thereof spaced along the length of the mat require spacing jigs in order to effect mass production. In addition, many of these previously known forms of mat constructions require extensive cleaning after each usage on soft ground and are difficult to correctly assemble when laying down a mat construction.

The mat construction of the instant invention, basically, includes a single rectangular planar surface defining member and only a single pair of transverse logs or members secured to and extending transversely of the opposite ends of the surface defining member.

When forming a roadway or platform a plurality of mat constructions are disposed with their surface defining member uppermost and their transverse logs or members lowermost and other mat constructions of the roadway or platform are inverted and disposed beneath the first mentioned mat constructions.

All of the mat constructions are of the same length and width and the transverse logs or members each have a width slightly less than one-quarter the length of the corresponding surface defining member and are spaced apart slightly greater than one-half the length of the corresponding surface defining member.

The inverted members, with the surface defining member lowermost and the transverse logs or members uppermost are first laid upon the ground in end-to-end aligned relation and the other mat constructions are then disposed over the inverted mat constructions with the spacing between the transverse end logs or members of each of the upper mat constructions receiving therein the adjacent transverse logs or members of adjacent ends of inverted mat constructions and the spacing between the transverse end logs or members of each lower mat construction receiving therein the adjacent transverse end logs or members of adjacent ends of the upper mat constructions.

The main object of this invention is to provide a mat construction for use in forming a roadway or platform on soft ground with a minimum amount of expense, transportation costs, difficulty in assembling the individual mat constructions in order to form a roadway or platform and ease of removal of the mat constructions after usage and cleaning thereof prior to subsequent usage.

Another object of this invention is to provide a mat construction in accordance with the preceding objects which will afford ground traction between the lower mat constructions and the ground upon which they are disposed.

Another object of this invention is to provide mat constructions formed in a manner such that surface traction of the upper mat constructions of a roadway or platform being with the wheels of vehicles traveling thereover may be increased.

Another very important object of this invention is to provide a mat construction which may be produced at low cost.

Still another object of this invention is to provide a mat construction of simple design which does not require the use of jigs during a mass production thereof.

A further object of this invention is to provide a mat construction which may be of one piece, molded construction.

A still further object of this invention is to provide a mat construction which will require minimum cleaning after each usage upon soft ground.

Yet another object of this invention is to provide a mat construction which may be molded primarily of wood products and resin.

Another object of this invention is to provide a platform mat construction of substantially eight feet in width and which may be made double wide to provide for a single lane roadway with the usual less than eight foot spacing between the wheels of vehicles serving to minimize downward depression of the outer margins of the roadway beneath soft ground over which the roadway is formed.

A final object of this invention to be specifically enumerated herein is to provide a mat construction which will conform to conventional forms of manufacture, be of simple construction and easy to use so as to provide a device that will be economically feasible, long-lasting and relatively trouble free in operation.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.

FIG. 1 is fragmentary perspective view of a double wide roadway constructed through the utilization of a plurality of right side up and inverted mat constructions of the instant invention and wherein the rectangular planar surface defining member of each mat construction is formed by a single unbroken panel member;

FIG. 2 is a perspective view of a modified form of mat construction wherein the rectangular planar surface defining member is constructed of four plank-type members and wherein each transverse log or member at the opposite ends of rectangular surface defining member is formed of a pair of closely spaces transverse plank members;

FIG. 3 is an enlarged end elevational view of the mat construction illustrated in FIG. 2;

FIG. 4 is an end elevational view of a one piece mat construction wherein the rectangular surface defining member and the transverse logs are integrally formed by a molding process;

FIG. 5 is a reduced bottom plan view of the mat construction illustrated in FIG. 4;

FIG. 6 is an enlarged fragmentary vertical sectional view taken substantially upon the plane indicated by the section line 6--6 of FIG. 1; and

FIG. 7 is a reduced side elevational view of the one piece mat construction illustrated in FIGS. 4 and 5.

Referring now more specifically to the drawings the numeral 10 generally designates a roadway which has been constructed over soft ground utilizing a plurality of mat constructions of the instant invention.

Each mat construction is referred to in general by the reference numeral 12 or 12' and includes a rectangular surface defining member 14 or 14' and a pair of opposite end elongated transverse logs or members 16 or 16'.

Each rectangular surface defining member 14 defines a first rectangular surface 18 and a second rectangular surface 20 facing opposite and paralleling the first surface 18. In addition, each transverse log or member 16 is secured to the opposite ends of the rectangular surface defining member 14 in any convenient manner.

The mat constructions 12' are identical to the mat constructions 12, except that the mat constructions 12' are one-half the width of the mat constructions 12.

The mat constructions 12 and 12' utilize one piece rectangular surface defining members 14 and 14' one piece transverse logs or members 16 and 16'.

When the mat constructions 12 and 12' have their first rectangular surfaces 18 and 18' disposed uppermost, the transverse logs or members 16 and 16' are secured to the undersides of the rectangular surface defining members 14 and 14'. However, when constructing the roadway 10, some mat structures 12 and also the mat structures 12' are disposed with their first rectangular surfaces 18 disposed uppermost and other mat structures 12 are disposed with their first rectangular surfaces 18 disposed lowermost.

The width of the transverse logs or members 16 and 16' is slightly less than one-quarter the length of the rectangular surface defining member 14 and 14' and the spacing between the transverse logs or members 16 and 16' of each mat structure 12 and 12' is slightly greater than one-half the length of the corresponding rectangular surface defining member 14 and 14'. In this manner, when constructing the roadway 10, a double row of mat structures 12 are disposed in end-to-end aligned and abutted relation with their second rectangular surfaces 20 and their transverse logs or members 16 disposed uppermost, see FIG. 6. Thereafter, a first row of mat structures 12 with their first rectangular surfaces 18 disposed uppermost and their transverse logs or members 18 disposed lowermost are centered over the first laid two rows of mat structures 12 in end-to-end aligned and abutting relation with the adjacent transverse logs or members of end abutted upper mat sections 12 received between the transverse logs or members 16 of the lower mats 12 and the transverse logs or members 16 of abutted ends of lower mats 12 received in the spacing between the transverse logs or mats 16 of the upper mat structures 12. Then, two rows of one-half width mat constructions 12' are disposed over the exposed remote side half marginal portions of the first laid two rows of mat constructions 12 with the half width mat constructions 12' aligned transversely of the roadway 10 with the corresponding upper mat structures. In this manner, the upper and lower mat structures 12 and 12' are tightly interlocked together against relative longitudinal shifting and the friction between the upper and lower mat structures 12 and 12' strongly resists relative lateral shifting between upper and lower mat sections 12 and 12'. Further, when a vehicle with slightly less than eight foot spacing between opposite side wheels is driven down the center of the roadway 10 on the center row of upper mat structures 12, the weight of the vehicle is supported more from the adjacent margins of the underlying bottom mat structures 12 and, thus, there is little tendency for soft mud at the longitudinal margins of the roadway 10 to bulge up and overflow the roadway longitudinal margins.

The mat sections 12 and 12' may be constructed entirely of wood with the transverse logs or members 16 and 16' comprising large transverse planks and with the rectangular surface defining members comprising heavy plywood panel sections, both the rectangular surface defining members 14 and 14' and the transverse log or members 16 and 16' being treated against rot.

With attention now invited more specifically to FIG. 2 of the drawings, there may be seen a modified form of mat structure 112 which utilizes four individual plank sections 113 as the rectangular surface defining member thereof and a pair of plank members 116 defining each of the transverse logs or members thereof. The plank members 113 are slightly spaced apart to allow heavily laden rubber tire areas aligned with the spacing between adjacent plank members 113 to be depressed downwardly between adjacent planks 113 in order to increase traction between the tires of wheeled vehicles and the first rectangular surface 118 of the mat structure 112. Here again, the plank members 113 and 116 may be constructed of wood or even molded of wood products mixed with resin. Of course, the mat structure 112 also may be constructed as a one-half mat structure and used in the same manner as the mat structure 12'.

Referring now more specifically to FIG. 4, the reference numeral 212 refers to a third form of mat structure which is of one piece construction and constructed of a mixture of wood chips and resin, or the like. The first rectangular surface 218 of the mat structure 212 includes four integral longitudinally extending, transversely spaced and generally inverted V-shaped ridges 219 for increasing traction between a wheeled vehicle and the first rectangular surface 218. The transverse logs or members 216 or formed integrally with the rectangular surface defining member 214 of the mat structure 212. The ridges 219, in addition to affording increased traction between the first rectangular surface 218 and wheeled vehicles moving thereover, also provide longitudinal stiffening for the mat structure 212. Also, as before, the mat structure 212 may be constructed as a one-half width mat structure.

It has been found that utilizing only two transverse logs or members at the opposite ends of each mat section 12 or 12' results in simplified construction of the mat sections 12 and 12', as opposed to mat sections previously known which incorporate more than two transverse log members or planks and which are interdigitated with relatively inverted mat sections of the same type. Previous mat sections utilizing more than two log members must be constructed through the utilization of jigs to insure proper spacing between the transverse log members and they are more difficult to clean after usage on soft ground to insure that the interdigitation of the log members of relatively inverted mat sections subsequently may be accomplished.

With applicant's invention it is only necessary to provide the rectangular surface defining members 14 and 14' and transverse logs or members 16 and 16' of the correct dimensions. Then, the transverse logs or members 16 and 16' may be readily secured to the opposite ends of the rectangular surface defining members 14 and 14', inasmuch as the transverse logs or members are substantially aligned with the end edges of the rectangular surface defining members 14 and 14' and the opposite side longitudinal margins of the rectangular surface defining members 14 and 14'. This type of construction enables the mat structures 12 and 12' to be assembled by persons having minimum education and instruction while still providing a product which is superior in its ability to be quickly erected in order form a roadway such as the roadway 10 and also its ability to be readily cleaned for subsequent usage.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.