The invention relates to a floor for a container i.e. intermodal container, a truck or a railway wagon, where the floor comprises at least one floor section. The invention further relates to a method of manufacturing a floor section of a floor and a container comprising a floor part, an end wall, a roof lining forming a ceiling, two opposite side walls and a floor. Shipping containers for transporting dry freight are typically available as 20 ft and 40 ft containers and are generally constructed of corrugated steel sheets for the side walls. The flooring inside the container is supported by several steel cross members running horizontally across the width of the container. The floor in a refrigerated container, also referred to as a reefer, is generally formed by using an extruding process to form an aluminum profile comprising a number of parallel T-bars forming a number of channels or air ducts, sometimes referred to as a T-Floor. The T-bars or T-slots are primarily used to obtain an increased airflow in the interior of the container.

The problem to be solved is to provide a floor comprising a number of floor sections with protruding elements forming channels or air ducts, the floor sections having a low weight and at the same time achieving a sufficient mechanical strength of the protruding elements arranged on each floor section.

Another problem to be solved is to provide a floor for a fully welded structure, where the fully welded structure comprising a number of floor sections including protruding elements such as T-grating for transporting air inside the fully welded structure such as a container, where the floor sections have a higher corrosion resistance and to reduce the risk of water ingress in the connecting points due to the fully welded structure. This can be achieved by a floor for a container:

- wherein the floor section is formed from a single sheet element and includes a number of protruding elements and a base;

- the floor section has a rectangular shape with a length extending in a first direction and a width extending in a second direction being perpendicular to the first direction;

- each protruding element includes a head and a base element having two side walls extending perpendicularly from a base of the floor section, wherein the two side walls are formed with a spacing in between each other;

- wherein an air duct is formed between two neighbouring protruding elements for allowing air to be guided in said air duct;

- wherein a distance between two neighbouring heads is smaller, than a maximum width of the air duct having a ratio of 1 : 1 ,2 to 1 :2,5, preferably a ratio of 1 :1 ,5 to 1 :1 ,9.

The invention brings about the possibility to provide a floor for a container made from stainless steel material having a higher corrosion resistance compared to floor made from aluminium, hereby achieving a container being more water tight compared to common available refrigerated containers. It is possible to increase the number of air ducts for each floor section. The air ducts are used for guiding the air from the front of the container to the goods placed and anchored to the floor and the air ducts will therefore ensure an even distribution of air between the goods inside the container

The invention provides a floor comprising a number of floor sections for a container, where the protruding elements are integrated into the floor sections, it is hereby possible to provide a floor, where the protruding elements are more durable to the step of loading and unloading the cargo being placed inside the container. A further advantage is, that the present invention provides a floor having a number of floor sections with protruding elements, where the protruding element(s) have a higher impact strength compared to the connecting means used in the common available refrigerated containers, where the connecting means are made from an extruded aluminum material. Through the use of a roll forming manufacturing process, it is possible to obtain a floor section with protruding elements, which due to the manufacturing process would result in less repair activities during the lifetime of the container as well as prolonging the lifetime of the floor.

The protruding element has a cross-sectional geometry, where each protruding element includes a base element having two side walls extending perpendicularly from a base of the floor section. The two side walls are formed with a spacing in between the two side walls, which is used for enhancing the air flow in the floor section. Each floor section has a substantially reduced material thickness compared to an aluminium floor made from extruded process, hereby achieving a lower weight of the floor section in the container.

As an advantage, the protruding elements on each floor section can be arranged with larger distance as the mechanical strength of steel is higher than comparable alternative floor section, which are typically manufactured of aluminium.

As an advantage, the weight and production cost of the floor is significantly reduced compared to similar comparable alternative floor section, which are typically manufactured from aluminium section.

In an embodiment, the base element is connected to the head by a pair of side walls and being substantially parallel with and offset relative to the base of the floor section, wherein the two side walls are parallel with each other.

Hereby a better and stronger connection between the wall and the floor can be obtained and it is furthermore possible to vary the distance between the two side walls as well as varying the distance between the base and the head of the protruding element.

In an embodiment, a transition portion is formed and located between the head and the two side walls. Through the use of a transition portion, it is possible to provide an enhanced anchoring of the cargo, which is to be retained relative to the floor. The transition portion could be implemented as an inclined wall between the side wall and the head or the transition portion could be a curved portion extending between the head and the transition portion.

In an embodiment, the base element is connected to a head being offset relative to the base of the floor section, wherein the two side walls are concave relative to one another. Through the use of a side walls being concave, it is possible to achieve a smooth transition between the head and the base element of the protruding element.

In an embodiment, each of the protruding elements extends in a first direction (X) of said floor section and the distance between two side walls being at least 1 mm and the distance H _d between neighbouring heads being at least 10 mm, the hears having a width H _w. By using a plurality of protruding elements extending in a first direction (X), it is possible to achieve a uniform distribution of the protruding elements along the first direction of each floor section.

In an embodiment, the base includes a first end and a second end positioned opposite the first end, wherein the first end of the base is elevated relative to the base and being configured for engaging a corresponding second end of another floor section. By using a floor section having a base with a first end being elevated relative to the second end, it is possible to achieve a larger connecting area between two neighbouring elements, which are to be connected together.

In an embodiment, the protruding element is formed by roll forming the sheet material into a number of floor sections including a number of protruding elements. By using a floor section made by using a roll forming process, it is possible to achieve as floor section having a substantially lower thickness, than a corresponding floor section made by using an extrusion process. In an embodiment, each floor section has protruding elements arranged in more than one row. By arranging the protruding elements in rows, it is possible to increase the number of air ducts for each floor section. The air ducts are used for guiding the air from the front of the container to the goods placed and anchored to the floor and the air ducts will therefore ensure an even distribution of air between the goods inside the container.

In an embodiment, the floor section forms an air duct for transporting a cooling air in each floor section of the container. A width of the air ducts A _w corresponds to a distance between side walls of two neighbouring protruding elements.

In the embodiment having curved side walls, the width of the air duct A _w corresponds to diameter of a partly tubeformed portion formed by two neighbouring protruding elements. In an embodiment, the single sheet element is metal sheet, preferably high grated stainless steel. Stainless steel has superior corrosion resistance compared to aluminum, which is commonly used for cooling containers such as refeers.

According to second aspect of the present invention, a container comprising a floor part, an end wall, a roof lining forming a ceiling, two side walls and a floor, where the floor is connected to each of the opposite side walls and an inner compartment being formed between the floor part and the floor, wherein the inner compartment formed by the floor part and an underside of the floor is adapted to be filled with an insulation material. The spacing between the two side walls of each protruding element (T-grating) would also be filled with the insulation material. According to a third aspect of the present invention a floor section for a container floor is provided, the floor section being formed from a sheet element and having a rectangular shape with a length extending in a first direction and a width extending in a second direction being perpendicular to the first direction, the floor section comprising:

a plurality of protruding elements extending from a base; wherein each protruding element extends longitudinally in the first direction and comprises: o a head; and

o two side walls connected between the base of the floor section and the head;

o wherein the head extends in the second direction by a first distance and at least a portion of the side walls extend in the second direction by a second distance and the first distance is greater than the second distance;

• wherein an air duct is formed between the base, the heads, and the side walls of two neighbouring protruding elements and is arranged to guide an air flow within the air duct.

According to a fourth aspect of the present invention a method is provided, which method of manufacture of a floor section for a container floor comprising:

providing a sheet element and having a rectangular shape with a length extending in a first direction and a width extending in a second direction being perpendicular to the first direction

forming a plurality of protruding elements extending from a base; wherein each protruding element extends longitudinally in the first direction and comprises:

o a head; and

o two side walls connected between the base of the floor section and the head;

o wherein the head extends in the second direction by a first distance and at least a portion of the side walls extend in the second direction by a second distance and the first distance is greater than the second distance;

• wherein an air duct is formed between the base, the heads, and the side walls of two neighbouring protruding elements and is arranged to guide an air flow within the air duct.

The above and other features and advantages of the present invention will become readily apparent to those skilled in the art by the following detailed description of exemplary embodiments thereof with reference to the attached drawings, in which:

Figure 1 A shows a schematic drawing of the inside of a container.

Figure 1 B shows a drawing of the floor for the container shown in FIG 1 A.

Figure 2 shows a close-up view (AA) of the floor shown in FIG 1 B.

Figure 3A shows close-up view (BB) of the floor shown in FIG 1 B. Figure 3B schematically shows a close-up view (CC) of four protruding elements according to one embodiment shown in FIG 3A.

Figures 4A-4C show alternative embodiments of the protruding elements. Figure 5 shows a principal drawing of a roll forming machine suitable for forming a single sheet into a floor section.

Various embodiments are described hereinafter with reference to the figures. Like reference numerals refer to like elements throughout. Like elements will, thus, not be described in detail with respect to the description of each figure. It should also be noted that the figures are only intended to facilitate the description of the embodiments.

An aspect or an advantage described in conjunction with a particular embodiment is not necessarily limited to that embodiment and can be practiced in any other embodiments even if not so illustrated, or if not so explicitly described. Throughout, the same reference numerals are used for identical or corresponding parts. Figure 1A shows a container 1 such as a reefer container from one end thereof. The container 1 could be a reefer container, a truck or railway container. The container 1 provides a cooling compartment comprising a floor part 2, an end wall 3 and a roof lining forming a ceiling 4 (roof structure) in the container 1 , a pair of opposite side walls 5 and an open end closable by a pair of doors 6, 7. A reefer unit (not shown) can be integrated in the end wall, e.g. the reefer unit could be installed afterwards.

The container can be used for transporting cargo and the container is substantially rectangular. All the structural parts such as side walls 5, floor part 2 of the container can be formed from metal sheet, preferably a steel material. Stainless steel or Fiber Reinforced Plastic (FRP) can be used on the inside as well. A floor 10 is configured to be positioned and arranged inside the container 1 . Reefer containers have the ability to maintain the cargo at the required temperatures for the duration of the transit of the cargo being stored inside the reefer container. The interior cladding or the lining can consist of steel sheet, such as stainless steel. Aluminium is commonly used for the roof part, as well is Fiber Reinforced Plastic (FRP) for roof and sides. The flooring inside the container allows for proper air circulation around perishable cargo as well as proper drainage of condensation. In all the FIGS, a sheet material is roll formed into a number of floor sections having a number of protruding elements 20, 20’, 20”. The single sheet element is metal sheet, preferably high grated stainless steel (HGSS). The floor 10 shown in FIG. 1 B is intended to be installed in the lower part of the container 1 more preferably resting on the floor part 2 of the container 1.

FIG 2 shows a close-up view (AA) of the floor shown in FIG 1 B. The floor consist of a number of floor sections 11 to form a floor 10 in a container. Each floor section 11 includes a number of protruding elements 20, which will be explained in further details with reference to FIGS 4A-4C. Each floor section 11 has a rectangular (polygonal) shape with a length (L) extending in a first direction (X) and a width (W) extending in a second direction (Y) being perpendicular to the first direction (X). FIG 2 shows only a part of the full length.

FIG 3A shows a floor similarly to the floor shown in FIG 1 B, but the floor consists of a number of floor sections 11 interconnected to form a floor for a container. A number of floor sections is formed from sheet material, where each floor section 11 has a number of protruding elements 20. The protruding elements can be arranged in more than one row. The floor 10 is formed by a number of floor sections 11 , each comprising a number of protruding elements 20. When all sections are interconnected forming the floor 10, the upper surfaces of the protruding elements 20 together constitutes a supporton which cargo can be placed and handled. The floor 10 is connected to each of a pair of opposite side walls 12 and an inner compartment is formed between the floor part 2 (shown in FIG. 1A) and the floor 10 and the inner compartment can be filled with an insulation material.

FIG. 3A shows a floor 10 for a container, in particular a refrigeration container, in a view from an end face. The floor 10 comprises a plurality of floor sections 11 , where each of the floor sections 11 are formed from a single sheet element and includes a number of protruding elements 20, more specifically each floor section 11 includes a number of protruding elements 20 and a base 28 (see FIG. 3B). The bottom of the floor section 11 is supported by a number of supporting elements 30 for at least partially supporting each floor section. As shown in FIG 3B, the base 28 includes a first end 29 and second end 30 positioned opposite the first end 29, where the first end 29 of the base 28 is elevated relative to the base and is configured for engaging a corresponding second end of another floor section 11 , as described above. An overlap of directly adjacent floor sections 11 is done by positioning the floor sections 11 beside one another with an overlap before welding the sections together. Flowever, it could be possible to form the floor without the floor sections overlapping each other by simply welding the edges together.

An internal spacing is formed between two side walls 22, 23 of the protruding element 20 and the internal spacing can be filled with a filler plastic. This filler plastic creates a shear-proof adhesive connection, so that the protruding element as a whole functions as shear-proof spacers.

In one embodiment, each protruding element 20 has a head 21 and the sheet material, from which the floor sections are made, can have a material thickness up to 2 mm, preferably 0.5-1 , 5 mm. The length (L) of the floor section 11 can amount to 5896 - 12035 mm. The width (W) of the floor sections 11 can amount to 2200 - 2350 mm. Each of the floor sections 11 can comprise of a number of protruding elements 20 and the floor 10 could consist of a number of floor sections 11. In one example each of the floor sections 11 can comprise of a number of between five and seven protruding elements 20 and the floor 10 could consist of a number of five to seven floor sections 11.

In FIGS 4A-4C, the each floor sections has a number of protruding elements 20, 20’, 20” and the base 28. The floor sections are produced by roll forming a steel sheet. In FIGS 4A and 4C, the base element includes two side walls 22, 23 connected to the base 28 via an inclined lower transition element 26, 27. Each protruding element has a stem portion being narrower than the head 21 having a width being shorter than the head 21. In this way, the head 21 overhangs the two side walls 22, 23. Referring now to FIGS 4A-4C, the floor 10 includes a number of floor sections 11 , where the base element includes a head 21 being substantially parallel with and offset relative to the base 28 of the respective floor section 11 , 11’, 11” shown in FIGS 4A-4C. Referring now to FIG 4A, the two side walls 22, 23 are parallel with each other and are being spaced from one another. A transition portion 220 is formed and located between the head 21 and the two side walls 22, 23.

Referring now to FIG 4B, the floor section 11’ has a base element including a head 21 being offset relative to the base 28 of the floor section 1 1’, wherein the two side walls 24, 25 are concave relative to one another. A transition portion 220 is formed and located between the head 21 and the two side walls 24, 25.

Referring now to FIG 4C, the two side walls 22, 23 are parallel with each other and are being spaced from one another, having a distace being greater than the distance betewwn the two side walls 22, 23 shown in the embodiment in FIG 4A. An inclining transition portion 220 is formed and located between the head 21 and the two side walls 22, 23. Figure 5 shows a principal drawing of a roll forming machine suitable for forming a single sheet into a floor section having a number of protruding elements. The roll forming machine comprising a number of first rollers 44, 46 and second rollers 42, 48, wherein the first rollers 44, 46 have a first rotational axis Z positioned substantially perpendicular to a first direction corresponding to the feeding direction X of the roll forming machine, wherein the second rollers 42, 48 have a second rotational axis Y being perpendicular to the first rotational axis Z. According to an aspect of the present invention a floor section 1 1 ,1 1’, 1 1” for a container floor 10, the floor section being formed from a sheet element and having a rectangular shape with a length L extending in a first direction X and a width W extending in a second direction Y being perpendicular to the first direction X, the floor section comprising:

a plurality of protruding elements 20’, 20”, 20” extending from a base 28; wherein each protruding element 20, 20’, 20” extends longitudinally in the first direction and comprises:

o a head 21 ; and

o two side walls 22, 23, 24, 25 connected between the base 28 of the floor section 1 1 , 1 1’, 1 1” and the head;

o wherein the head extends in the second direction by a first distance and at least a portion of the side walls extend in the second direction by a second distance and the first distance is greater than the second distance;

• wherein an air duct A is formed between the base, the heads, and the side walls of two neighbouring protruding elements 20, 20’, 20” and is arranged to guide an air flow within the air duct.

The floor section 1 1 ,1 T, 1 1” for a container floor 10 can be manufactured by a method comprising:

providing a sheet element and having a rectangular shape with a length (L) extending in a first direction (X) and a width (W) extending in a second direction (Y) being perpendicular to the first direction (X)

forming a plurality of protruding elements 20’, 20”, 20” extending from a base 28; wherein each protruding element 20, 20’, 20” extends longitudinally in the first direction and comprises:

o a head 21 ; and

o two side walls 22, 23, 24, 25 connected between the base 28 of the floor section 1 1 , 1 T, 1 1” and the head;

o wherein the head extends in the second direction by a first distance and at least a portion of the side walls extend in the second direction by a second distance and the first distance is greater than the second distance;

• wherein an air duct A is formed between the base, the heads, and the side walls of two neighbouring protruding elements 20, 20’, 20” and is arranged to guide an air flow within the air duct.