The present invention relates to a rig mat system that are widely used as a ground cover system on soft soil in many fields such as civil engineering, transportation, industry, oil and gas exploitation and military.

Background of the invention

In the prior art, traditional rig mats have been used mainly for the oil and gas industry and other industries for many years. Previously, a traditional steel rig mat consisted of a number of common shaped steel beams (for example, C-shaped or I-shaped steel beam) and they are welded to each other rigidly. Those longitudinal and lateral beams defining desk insert with opening therebetween. These frames are constructed so that it can be inserted with wooden slabs inside the opening spaces. These slabs are made of wooden slats (blocks). These slats or blocks are arranged along the frame in the opening spaces to create the floor surface of the rig mat. Because there are only a few longitudinal bars (three or four bars) in the main bearing direction, this type of road mat often has a large deflection under heavy load and is easily damaged or deformed so hard to recover.

In the prior art, traditional rig mats with common shaped steel frames have some inherent disadvantages. These shaped steel beams with fixed height and width leads to in flexibility in designing the mat with different sizes or thickness (height), so it cannot meet all needs of users (customers). Shaped steel beams are usually thick, heavy and they have not better bearing capacity than many cold-formed steel structures today.

Traditional rig mats use a large amount of wood to be used as desk insert. During operations, wooden blocks can absorb water then the weight can be increased and they are susceptible to damage by loads, the environment and insects. After 1-2 years of use, the rig mat with wooden block inserts is easily damaged. Moreover, the damaged woodent blocks are difficult to be replaced because the steel frames have been welded together firmly. That leads to the cost of replacement, transportation and handling in general for traditional rig mats. Moreover, due to the scarcity of timber resources, the heavy use of wood will lead to a negative impact on the environment.

Meanwhile, the traditional types of rig mats have low bearing capacity, and they are not flexible in designing and manufacturing rig mats with different sizes and structures. These common rig mats use a lot of wood and thick steel beams that contribute to heavier weight, so they cost a lot to transport and haldle while the bearing capacity is poor. Morover, the excesive use of wood resources can affect badly to the environment, the wooden block has low durability that makes the repair and maintenance cost increase, so users want to order a superstructure steel rig mat type which is manufactured by cold- formed steel plates with lighter weight while ensuring bearing capacity, durability, and low maintenance.

Thus, due to the fact that the use of rig mats, it is necessary to develop a completely new type of steel rig mat with lighter weight, better bearing capacity and durability and more flexible in design and manufacturing.

Summary of the invention

In an embodiment of the present invention, a steel superstructure rig mat that are shapes manufactured from steel plates is provided. The steel superstructure rig mat consists of a surface plate with V-shaped longitudinal ribs; longitudinal U-shaped beams along the length of the mat; cross-grider beams and other steel plates such as bottom and surrounding plates that forming the appearance of the mat. The surface plate with V- shaped longitudinal ribs significantly increase the roughness and hardness of the surface of the mat itself. Longitudinal U-shaped beams are arranged in parallel with each other and welded to the underside of the surface plate. Cross-grider beams are arraged perpendicular to the U-shaped beams. This superstructure results rignlat significantly stronger but ligher than the traditional rig mat. Two ends of the mat are designed in a taper shaped with a simple simple but effective interlocking system that helps the mats can be easily paired together to create a solid matting system. The features and advantages of the present invention will become more apparent after reviewing the following description of some illustrative embodiments and the appended claims.

Brief description of the drawings

The present invention as summarized above will now be described with reference to the accompanying drawings of specific embodiments so as to demonstrate the subject matter and advantages of the present invention with additional clarity and details. However, it is to be understood that the embodiments disclosed herein are only the typical embodiments and are not intended to limit the scope of the present invention. In the drawings:

Fig.1 is a perspective view of a superstructure rig mat of cold-formed steel

Fig. 2 is a plan view of upper surface of the mat with the the expression of the V- ribbed surface according to a specific embodiment of the present invention;

Fig. 3 is a side view of the mat according to a specific embodiment of the present invention;

Fig. 4 is a cross section along A-A in Fig.2;

Fig. 5 is a partial view in Fig.4;

Fig. 6 is a bottom view from the B-B section in Fig.3, between the top plate and the bottom plate of the mat according to a specific embodiment of the present invention;

Fig. 7 is the section along the C-C in Fig.2;

Fig. 8 is a partial view of Fig.7;

Fig. 9 shows an inter-locking enlargement view at both ends of the mat according to a specific embodiment of the present invention. Detailed description of the invention

The present invention will be described in detail with reference to the figures from Fig.l to Fig.9. Accordingly, the superstructure rig mat of cold-formed steel consists of parts as described below.

As shown In Fig.l and Fig.2, the surface steel plate 1 has a major role to receive the direct impact of the load of equipments as well as vehicles moving above. The surface steel plate 1 is made from a cold-formed steel plate with multi- V-shaped ribs 11 running along the length of surface plate 1. This surface plate 1 is arranged as top of the rig mat so that the V-shaped ribs faces upwards. V-shaped ribs is desinged in addition to enhancing the rigidity of surface plate 1 but also increasing the friction for vehicles and people when moving on the surface of the rig mats. This invention also results to higher safety.

As shown In Fig.4, Fig.5 and Fig.6, U-shaped beams 2 are manufactured from cold-formed steel by bending / stamping and they are welded to the underside of surface plate 1 along the length of the surface plate 1. The number of U-shaped beams will depend on the width of the rig mat and the bearing capacity requirements of the rig mat.

As shown In Fig.5, Fig.6, Fig.8 and Fig.9, lateral support bars 3 are steel plates with widen foot. They can be designed in L-shaped or inverted T-shaped, with the upper parts are fixed welded to the bottom of U-shaped beams 2 and perpendicular to these U- shaped beams. Widen foot is welded fixed to the bottom plate of the rig mat.

As shown In Fig.3, Fig.4 and Fig.7, the bottom plate 4 is made of plain steel plate with the shape and size the same to the surface plate 1 , and placed parallel to the surface plate 1, but slightly skewed along the longitudinal edge of the rig mat.

As shown In Fig.l, Fig.2, Fig.3 and Fig.6, two inclined plain steel plates 5 and 6 are welded at both ends of the mat on the same side of surface plate 1 and bottom plate 4 to form tapter shapes, two inclined edges of the tapers is parallel to each other to form a parallelogram shape of the rig mat when viewed from the side. As shown in Fig.l and Fig.3, the two side steel plates of the rig mat 7, in the parallelogram shapas mentioned above, are welded to the respective edges of surface plate 1 , bottom plate 4 and inclined plates 5, 6. forming a box.

The rig mat in the complete according to an embodiment of the present invention has the overall shape as shown in Fig.l and Fig.2.

The present prevention can be manufactured with arbitrary dimensions. According to a preferred alternative, the rig mat has a width of 2.4m, a length of 6m -12 m, and a thickness (height) of 0.1 - 0.15m.

When it is necessary to combine the rit mats according to the embodiment of the present invention into a single surface, a system of rig mats, which the mats are interconnected together by an inter-locking system 8 mounted on the plates 5 and 6 of the rig mat. According to a preferred alternative, this inter-locking mechanism 8 consists of a female connector 81 and a male connector 82 are created on the two inclined plates 5 and 6, respectively, so that when the two mats are assembled together, the femal connector 81 of one mat will be locked with male connector 82 of the adjacent mat. According to a specific alternative, the femal connector 81 is created on the plate 5 that is facing upwards, and the male connector 82 is created on the plate 6 that faces downwards (Fig.9).

In order to facilitate the movement and hanlding work of the rig mat by crane, each mat is designed with a number of hanging shackles 9, preferably there are four 9 hanging shackles created near the respective corners of the mat (Fig. 8 and Fig. 9).