Abstract:
The present invention disclosed a shipping container comprising a pair of side walls, a rear end, a front end, a roof, a floor and a base frame; said base frame further comprising two longitudinal bottom side rails and numbers of parallel bottom cross members, wherein said floor is made up of corrugated steel floor. On the premise of passing ISO test, it provides a container which is lighter in tare weight, less in material consumed and lower in production cost.

Description:
RELATED APPLICATION  
       [0001]     The present application is a further divisional application of patent application of Ser. No. 10/939,173 filed on Sep. 10, 2004 entitled A SHIPPING CONTAINER, which was a divisional application of a patent application of Ser. No. 10/200,786 filed on Jul. 22, 2002 and now abandoned entitled A SHIPPING CONTAINER. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to a shipping container, and more particularly, to the floor of a container.  
       BACKGROUND OF THE INVENTION  
       [0003]     Containers were first used in cargo transportation in U.S.A in 1956. After more than 40 years&#39; development, containers have been used worldwide. In the course of the development of the container, designers and manufacturers are devoted to improvements on its structure, so as to improve the functions of the container, reduce the material consumed and the production cost.  
         [0004]     As shown in  FIGS. 1, 1A ,  1 B,  1 C, a conventional shipping container consists of a pair of side walls  1 , a rear end  2 , a front end  3 , a roof  4 , a floor  5  and a base frame  6 , where the base frame  6  and the floor  5  constitute the bearer for the cargoes in the container which is also called the base assembly.  
         [0005]     As shown in  FIGS. 2, 3 ,  4  and  5 , the conventional container base frame mainly comprises two bottom side rails  601 , numbers of bottom cross members  602 , where the two ends of the bottom cross members  602  are welded to the bottom side rail  601  respectively, constituting a rigid integral frame structure. In the conventional container, plywood floor  5  (28 mm) is paved on the bottom cross members  602 , and joined with the bottom cross members  602  by screws  603 , the plywood floor  5  and the base frame  6  make up the bearer for the cargoes in the container.  
         [0006]     To pass the International Organization for Standardization (ISO) test for containers, the cross members need to be arranged in high density with quantities of beams, and the bottom cross members should be made of thick steel plates to satisfy the strength requirement, therefore, large quantity of material is consumed. In addition, the floor is made of special hard wood. On one hand, there exist several shortcomings such as: a great diversity in quality, expensive price, high cost, and easily influenced by possible shortage of plywood floor supplies. On the other hand, since it is thicker (28 mm) in thickness, the plywood floor is heavier in weight, and the tare weight of the container is heavier accordingly.  
       SUMMARY OF THE INVENTION  
       [0007]     The main object of the present invention is to overcome the shortcomings of the conventional container, and by making improvements on its floor, to provide a container which is lighter in tare weight, less in material consumed and lower in production cost.  
         [0008]     The aim of the present invention can be achieved as follows:  
         [0009]     A shipping container comprising a pair of side walls, a rear end, a front end, a roof, a floor and a base frame; said base frame further comprising two longitudinal bottom side rails and numbers of parallel bottom cross members, wherein said floor is made up of corrugated steel floor. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1 ,  FIG. 1A ,  FIG. 1B  and  FIG. 1C  show respectively the front, left, right and top views of a conventional container;  
         [0011]      FIG. 2  is a partial top view of the base frame and plywood floor of the conventional container;  
         [0012]      FIG. 3  is a cross sectional view taken along the A-A line of  FIG. 2 ;  
         [0013]      FIG. 4  is a cross sectional view taken along the B-B line of  FIG. 2 ;  
         [0014]      FIG. 5  is a schematic diagram showing the connecting structure between the bottom cross members and the plywood floor of the base assembly shown in  FIG. 2 ;  
         [0015]      FIG. 6  is a cross sectional view of a preferred embodiment according to the present invention;  
         [0016]      FIG. 7  is a partial top view of the base frame and corrugated steel floor of the container shown in  FIG. 6 ;  
         [0017]      FIG. 8  is a cross sectional view taken along the A-A line of  FIG. 7 ;  
         [0018]      FIG. 9  is a partial perspective view illustrating a kind of base frame which is made up by C-shaped bottom cross members and corrugated steel floor;  
         [0019]      FIG. 10  is a partial perspective view illustrating another kind of base frame which is made up by L-shaped bottom cross members and corrugated steel floor;  
         [0020]      FIG. 11  is a cross sectional view taken along the B-B line of  FIG. 7 ;  
         [0021]      FIG. 12  is a schematic diagram illustrating the connecting structure between the bottom cross members as shown in  FIG. 9  and the corrugated steel plates in the container shown in  FIG. 6 ;  
         [0022]      FIG. 13  is a cross sectional view illustrating a kind of corrugated steel plate with stuffing in its grooves according to the present invention;  
         [0023]      FIG. 14  is a cross sectional view illustrating another kind of corrugated steel plate with thin plate paved on it according to the present invention;  
         [0024]      FIG. 15  is a partial perspective view illustrating floor structure according to the present invention;  
         [0025]      FIG. 16  is a perspective partial cross sectional view illustrating the continuous corrugated steel floor with stuffing in its grooves according to the present invention;  
         [0026]      FIG. 17  is a perspective partial cross sectional view illustrating the disconnected corrugated steel floor with stuffing in its grooves according to the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]     As shown in  FIG. 6 , the shipping container of this invention consists of a pair of side walls  130 , a rear end, a front end, a roof  430 , a base frame  630  and a corrugated steel floor  530 .  
         [0028]     As shown in  FIGS. 7, 8 ,  11  and  12 , the base frame of the container mainly comprises two bottom side rails  631  and several bottom cross members  632 ; both ends of the bottom cross members  632  are welded to the side of the bottom side rails  631  respectively; corrugated steel plate  530  is paved on the bottom cross members  632 , and welded on the bottom cross members  632  and two bottom side rails  631 , constituting a rigid bearer for cargoes in the container.  
         [0029]     Since steel is much better in synthetic mechanics performance than wood, and corrugated floor has good bending resistant capability, which are specially advantageous for satisfying loading requirements and application features of container floor, the corrugated steel floor  530  is better in mechanics performance and has higher load bearing strength than the prior art plywood floor. With the corrugated steel floor  530  adopted, thinner steel sheet and less material are required to achieve high bending resistant capability. Besides, the welding of the corrugated steel floor  530  with the bottom cross members  632  enhances the bending resistant strength of bottom cross members  632 , reduces cross sectional dimension, weight and cost. The corrugated floor  530  according to this embodiment made of 2 mm thick steel sheet is good enough to meet strength requirement.  
         [0030]     In the above base assembly, bottom cross members  632  and the corrugated steel floor  530  can be joined by many ways, and the two preferred ways are given below:  
         [0031]     As shown in  FIG. 9 , the corrugated steel floor  530  is directly paved on the bottom cross members  632 , and form a rigid integrated structure either by welding at the external sides or by rivet. The bottom cross members  632  can be made of steel of C-shaped cross sectional form.  
         [0032]      FIG. 10  illustrates another way of connecting the bottom cross members  632  with the corrugated steel floor  530 : the cross sectional form of the bottom cross members  632  is L-shaped, at the edge of the bottom cross member  632 , there are many convex teeth  633  matching with the concave grooves of the corrugated floor  530 , helping the bottom cross members to be welded to the corrugated steel floor.  
         [0033]     In above structures, the cross sectional form of the bottom cross members  632  can be L-shape, I-shape, T-shape, U-shape, C-shape or rectangle shape to suit the demands of various base frames.  
         [0034]     Compared to the prior art, the base assembly of this embodiment possesses following advantages□ 
         [0035]     (a) By substituting the prior art plywood floor with the corrugated steel floor, the rigidity and strength of the floor is enhanced, and thereby the load bearing capability of the base assembly is enhanced.  
         [0036]     (b) Since the rigidity and strength of the corrugated steel floor is enhanced, the space between cross members are widened, and thereby the quantity and amount of cross members are reduced.  
         [0037]     (c) Since the steel floor and cross members are welded into an integrated entity, the material around the welding spot will greatly enhance the bending resistant strength of the cross members.  
         [0038]     Therefore, on the premise of passing ISO test, the thickness of the bottom cross member according to this embodiment is 3 mm thick, while it has to be 4˜4.5 mm thick for bottom cross members of the prior art base assembly. The use of corrugated steel floor improves the bending resistant capability of bottom cross members, that is why the amount and weight of bottom cross members in this embodiment is much smaller than that of the prior art base assembly.  
         [0039]     To further meet the demands of various applications, make the surface of the corrugated floor as plain as the plywood floor for the ease of cargo loading□the floor structure of this embodiment can be improved in following ways□ 
         [0040]     As shown in  FIG. 13 , stuffing  531  can be filled in the concave grooves of the corrugated floor of the base assembly to make the surface of the corrugated floor flat. Stuffing  531  can be made of various kinds of materials such as wood, foam, plastics or other non-metal materials.  
         [0041]     Said non metallic stuffing filled in the grooves of the corrugated steel floor may be either continuously or incontinuously distributed along the grooves.  
         [0042]     As shown in  FIG. 14 , a layer of thin plate  532  can be paved on the surface of the corrugated floor of the base assembly as an alternative way to make the surface of the corrugated floor flat. The thin plate  532  can be made of a variety of materials, such as thin wooden plate, composite plate or steel plate.  
         [0043]     In order to fasten the cargoes in the container, some pieces of wood or other non-metallic materials may be retained on the floor  530 . Following improvements on the structure of the floor may be adopted:  
         [0044]     As shown in  FIG. 15 , the floor  530  consists of corrugated steel floor  533  in the main, and several plywood bars or other non metallic stuffing  531  such as wood, foam, or plastics, which are put together and paved on the base frame  630  of the container, constituting a rigid base assembly for loading. The floor  530  and base frame  630  may be jointed by welding, riveting, or connecting via screws.  
         [0045]     As shown in  FIG. 16 , which is a partial enlarged view of  FIG. 15 , the corrugated steel floor  533  is continuous at the position where the non metallic stuffing  531  is filled. The non metallic stuffing  531  is completely held within an integrated concavity  534  of the corrugated steel floor  533 .  
         [0046]     As shown in  FIG. 17 , the corrugated steel floor  533  is disconnected at the position where the non metallic stuffing  531  is filled. The non metallic stuffing  531  is held within a concavity  534  which is formed by two adjacent disconnected corrugated floors  533  and has an opening  535  at its bottom.  
         [0047]     As shown in  FIG. 15 ,  FIG. 16  and  FIG. 17 , the steel floor  533  is non uniform corrugated steel floor, which is formed by modifying the corrugated steel floor structure in partial. The wavelength of each corrugation is not equal to each other, and there is a wider concavity  534  at regular intervals, within which the non metallic stuffing  531  is installed.  
         [0048]     The grooves with non metallic stuffing filled in may be or not be in a certain proportion to the grooves without non metallic stuffing filled in.  
         [0049]     Alternatively, the steel floor may be common uniform corrugated steel floor, namely, the wavelength of each corrugation is equal to each other, where the grooves of the corrugated steel floor are made of the concavities of the corrugated steel floor itself, and the non metallic stuffing may be installed at intervals within the predetermined concavities.