Interlocking wooden mat roadway

Claim 1

A laminated wooden mat section of at least three ply construction adapted to be secured in interlocking relation to other like mat sections for constructing roadways in underdeveloped areas to be driven upon by the wheels of a motor vehicle, said mat section being of rectangular shape with a shorter side and a longer side at least 50% longer than said shorter side and comprising an intermediate layer of closely spaced planks of predetermined width and of substantially equal length extending parallel to each other for the length of the longer side of said rectangular shape from one edge to the other thereof, a bottom layer of substantially parallel wooden planks of predetermined width and of substantially equal length corresponding to the length of the shorter side of said rectangular shape, secured to said intermediate layer of planks at right angles thereto by nailing, with the ends thereof secured to the outermost planks of said intermediate layer to define said rectangular shape, at least one plank of said bottom layer being longitudinally offset to provide a male extension at only one end and a female recess only at the other end of said bottom layer, a top layer of substantially parallel wooden planks of predetermined width and of substantially equal length corresponding to the length of the shorter side of said rectangular shape, secured to said intermediate layer of planks at right angles thereto by nailing, said top layer comprising two groups of closely spaced planks, each group of planks being of sufficient width and spaced one group from the other a sufficient distance to provide parallel tracks for the wheels of a motor vehicle when said mat sections are assembled into a roadway, at least one of said top layer groups of planks having an internal longitudinal space of substantially the width of one of said planks, said layers being securely attached together at common overlapping intersections, and said bottom layer male extensions being adapted to fit and be removably secured in said female recess on an adjacent mat by being lowered into position for assembly along the longer edge of said rectangular shape with the edges and ends, respectively, of adjacent mats being in a straight line and said groups of top layer planks being aligned to define said parallel vehicle tracks, said mat sections being substantially lighter in weight than mats having closely spaced planks on each of the layers thereof and being constructed to permit a vehicle to move along a previously laid mat while laying the next mat in the roadway being assembled.