CA2691669A1 - Road mat - Google Patents

Abstract

A road mat having a body formed entirely of multiple layers of thin wood fibre compressed and bonded together by resins. This road mat can be left in place to decompose naturally at the end of its use, thereby eliminating the environmental disturbance associated with removal.

Description

TITLE
[0001] Road Mat FIELD

[0002] There is described a road mat used to permit vehicular travel over environmentally sensitive areas, such as muskeg, permafrost or soft ground.

BACKGROUND

[0003] There are four types of road mats that are currently being used. A
first and most commonly used form of road "mat" made by bolting together three layers of 2 X
8 oak or fir lumber to form a mat that is approximately 6 inches thick. This first mat contains between one hundred and two hundred vertically aligned 6 inch bolts. A second road "mat" is made by bolting together sixteen 6 X 6 X 14 ft. pine timbers. This second mat uses horizontally aligned four 8 foot long steel bolts. A third road "mat" places the wood timbers within a steel frame.
A fourth, and least common form of road "mat" is made by extruding various "plastics" to form a mat.

[0004] Typically all of these types of mats are 8 feet wide and 14 feet long and they may or may not be somewhat interlocking. All of these mats are most commonly used in the same way - they are laid end to end and two mats wide on the surface of the ground after minimal disturbance (clearing and/or levelling). They are occasionally laid in side by side relation, instead of end to end.

[0005] When road access is no longer require, the mats are removed because of the metals, plastics or other environmentally objectionable components. Most of these mats are intended to be used several times. Removal can cause more environmental damage than placing the mats, because the road mats tend to "sink" into the soft soil.
They may also become frozen in, thus requiring considerable force to extract them. What is required is a road mat for which environmental damage during removal is not an issue.
SUMMARY

[0006] There is provided a road mat having a body formed entirely of multiple layers of thin wood fibre compressed and bonded together by resins.

[0007] This road mat provides a number of advantages, as will hereinafter be further described. A primary advantage is that the road mat can be left in place to decompose naturally at the end of its use, thereby eliminating the environmental disturbance associated with removal.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] These and other features will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to be in any way limiting, wherein:

[0009] FIG. 1 is a perspective view of a road mat made of cross-oriented layers of thin wood fibre compressed and bonded together by resins.

[0010] FIG. 2 is a side elevation view of the road mat illustrated in FIG. 1.

[0011] FIG. 3 is an exploded perspective view of the road mat illustrated in FIG. 1.
DETAILED DESCRIPTION

[0012] A road mat generally identified by reference numeral 10, will now be described with reference to FIG. 1 through FIG. 3.

Structure and Relationship of Parts:

[0013] Referring to FIG. 1, road mat 10 has a body 12 which is preferably the size of all standard road mats which is six inches thick, eight feet wide and fourteen feet long. However, it will be appreciated that road mat 10 will remain functional in smaller sizes as long as body 12 is at least four inches thick, at least four feet wide and at least twelve feet long. It is preferred that road mat 10 be at least four inches thick in order to provide sufficient strength to support a motor vehicle. It is preferred that road mat 10 be at least four feet wide, so two road mats placed side by side can readily handle the wheel base of a motor vehicle. It is preferred that road mat 10 be at least twelve feet long, so as to accommodate the distance between a front axle and a rear axle on a motor vehicle. It will be understood that road mat 10 may also be made thicker, wider or longer than a standard road mat. For example, a road mat which was seven inches thick, twelve feet wide and twenty feet long would still be viable. An upper size limit is dictated by shipping, handling and manufacturing considerations. Referring to FIG. 2, optionally road mat 10 may have a textured upper travel surface 16.
One way of texturing upper travel surface 16 is to embed sand 18, gravel 20 or both in with wood fibre 14 in upper travel surface 16. There are alternative ways of texturing upper travel surface 16, such as through the use of a series of corrugations.

[0014] Referring to FIG. 3, in this example road mat 10 is formed entirely of multiple layers of thin wood fibre 14. The cross-oriented layers preferably include axial layers 22 which are oriented parallel to longitudinal axis 21 of road mat 10 and transverse layers 24 which are oriented transverse to longitudinal axis 21 . It will be appreciated that there are other layer orientations which could be utilized. Axial layers 22 and transverse layers 24 are compressed and bonded together by resins 26. Wood fibre 14 can take various forms, such as elongated strips or shorter wafers.

[0015] Referring to FIG. 2, in this example body 12 has a first engagement 28 at a first end 30 and a second engagement 32 at a second end 34. First engagement 28 is capable of engaging with a second engagement 32 on a body of a like road mat.

[0016] In broad terms, the process of making road mat 10 is the same process used for making oriented strand board and other strand based products. As this process is well known, it will not be further described. However, strand based products do not come in thicknesses that approach four to seven inches. Current strand based product fabrication uses heat to cure the resin. This involves the use of heat plates, often using steam injection.
The thickness of strand based products is limited by the ability to apply heat to cure the resin. At best, heat plate technology is only effective within a range of two inches. There are two alternative approaches that are currently being considered to achieve the greater thicknesses. One approach is to continue the deposit of wood fibre 14 until the required thickness is attained, but use alternative means for curing the resin, such as microwaves or a radio frequency technology. Another approach is to form the thickest strand based products possible with existing heat plate technology and then use resin to bond multiple oriented strand based products together to achieve the required thickness in a cold pressing process that will not adversely affect the integrity of the stand based products. .

Advantages:

[0017] There are a number of advantages that road mats 10 provide:
1. Wooden mats are sometimes inconsistent in quality, depending upon the quality of the wood that is available at time of manufacture. It is increasingly difficult to obtain good quality wood at a reasonable price or at all. Road mats will be of uniform quality. Furthermore, they can be tailored to meet the specific needs of the user regarding durability, strength, and other characteristics such as surface characteristics. Surface characteristics can be 10 important to avoid slippage or surface damage. In order to avoid slippage the surface can be corrugated or sand can be embedded in the surface. In order to reduce surface damage by tracked vehicles, gravel can be embedded in the surface.
2. As Road mats 10 are made entirely of wood fibres and resins with no metals, plastics or other materials, they can be left in place to decompose naturally at the end of their use, thereby eliminating the environmental disturbance associated with removal.
3. The resins can be made to suit the durability requirements of the particular application. As a result the road mat can be engineered to disintegrate and start to decompose according to a schedule timed to coincide with the end of its projected use.
4. Road mats are used to protect the permafrost in the far north. In permafrost situations, losing the frost has very significant environmental implications.
Removing the road mats when a project is over leaves the soil underneath exposed to sunlight and hastens thawing. As road mats 10 are left in place, they will act as an insulator, and protect the permafrost.
5. There are some areas that are only accessible in winter, when soft and otherwise impassable ground becomes frozen. In such areas winter "roads"
of ice and snow are created. When road mats are used, they tend to "insulate"
the ground surface, so that the hauling season can often be extended by several weeks. This has a huge economic implications.

[0018] In this patent document, the word "comprising" is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not 5 excluded. A reference to an element by the indefinite article "a" does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements.

[0019] The following claims are to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, and what can be obviously substituted. Those skilled in the art will appreciate that various adaptations and modifications of the described embodiments can be configured without departing from the scope of the claims. The illustrated embodiments have been set forth only as examples and should not be taken as limiting the invention. It is to be understood that, within the scope of the following claims, the invention may be practiced other than as specifically illustrated and described.

Claims (7)

1. A road mat, comprising:
a body of at least 4 inches thick, at least four feet wide and at least twelve feet long formed entirely of multiple layers of thin wooden strips of wood fibre compressed and bonded together by resins.

2. The road mat of Claim 1, wherein the body has an upper travel surface which is textured.

3. The road mat of Claim 2, wherein the upper travel surface is textured by surface corrugations.

4. The road mat of Claim 2, wherein the upper travel surface is textured by embedding sand, gravel or other natural materials into the upper travel surface.

5. The road mat of Claim 1, wherein the body has a first engagement at a first end and a second engagement at a second end, the first engagement engaging with a second engagement on a body of a like road mat.

6. The road mat of Claim 1, wherein the body is formed by compressing wood fibre and bonding using a heat activated resin.

7. The road mat of Claim 1, wherein the body is formed by cold bonding process in which multiple layers of strand based products are bonded together.