Shipping container

[0001] The present invention relates to a shipping container, and more particularly, to the improvements on the structure of a container.

[0002] Containers were first used in cargo transportation in U.S.A. in 1956. After more than 40 years 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.

[0003] As shown in FIGS. 1, 1A, 1B, 1C, 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.

[0004] 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.

[0005] 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.

[0006] The side panel of the container is usually made of corrugated plate. As shown in FIGS. 6 and 7, the cross section of the conventional side panels is a corrugated structure made up by a number of identical wave crests, slopes and wave troughs, where the slope projection length I on the wave crest plane is relatively longer and the wave height D is relatively shorter. The conventional corrugated structure of the side panels is not advantageous for enhancing the bending resistant capability of the corrugated plate, therefore, thicker steel sheet and high strength material have to be adopted to pass ISO test. Use of high strength material drives up the material cost and use of thicker steel sheet not only increases material cost and tare weight, but also decreases the loading capacity and efficiency.

[0007] The main object of the present invention is to overcome the shortcomings of the conventional container, and by making improvements on its structure, 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 by improvements on its base frame as follows:

[0009] A 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 base frame further includes at least one longitudinal member, said longitudinal member is in parallel with said bottom side rails, and connected with at least two of the bottom cross members.

[0010] Said base frame may include at least two longitudinal members, the space between two longitudinal members is no longer than 600 mm, and it is preferred to be no longer than 180 mm.

[0011] Said longitudinal members may be shorter than said bottom side rails, and only distributed within partial area of the entire base frame, i.e., said longitudinal members only cross some of the bottom cross members.

[0012] Said base frame may further include supporting beams tilted installed at the corner of the cross made up by the longitudinal members and the bottom cross members.

[0013] The aim of the present invention can be achieved by improvements on its floor as follows:

[0014] A 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.

[0015] The aim of the present invention can be achieved by improvements on its side panels as follows:

[0016] A container comprising a pair of side walls, a rear end, a front end, a roof, a floor and a base frame; the cross section of said side walls is a corrugated structure made up by a number of identical wave crests, slopes and wave troughs, wherein the wave height D between said wave crest and wave trough is 36<D54 mm.

[0017] The length of said slope projection on said wave trough plane is 0I25 mm the thickness of said side panel is 0.8-1.2 mm.

[0018] FIG. 1, FIG. 1A, FIG. 1B and FIG. 1C show respectively the front, left, right and top views of a conventional container;

[0019] FIG. 2 is a partial top view of the base frame and plywood floor of the conventional container;

[0020] FIG. 3 is a cross sectional view taken along the A-A line of FIG. 2;

[0021] FIG. 4 is a cross sectional view taken along the B-B line of FIG. 2;

[0022] 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;

[0023] FIG. 6 is a schematic diagram of the side panels of the conventional container;

[0024] FIG. 7 is a cross sectional view taken along the A-A line of FIG. 6;

[0025] FIG. 8 is a partial top view of the base frame and plane steel floor in the first preferred embodiment according to the present invention;

[0026] FIG. 9 is a cross sectional view taken along the A-A line of FIG. 8;

[0027] FIG. 10 is a partial enlarged perspective view illustrating a kind of connecting structure between the bottom cross members and the longitudinal members of the base frame shown in FIG. 8;

[0028] FIG. 11 is a partial enlarged perspective view illustrating another kind of connecting structure between the bottom cross members and the longitudinal members of the base frame shown in FIG. 8;

[0029] FIG. 12 is a cross sectional view taken along the B-B line of FIG. 8;

[0030] FIG. 13 is a schematic diagram illustrating the connecting structure between the bottom cross members and the plywood floor of the base assembly shown in FIG. 8;

[0031] FIG. 14 is a front view of the corrugated plate used in the side panels of the second preferred embodiment according to the present invention;

[0032] FIG. 15 is a cross sectional view taken along the A-A line of FIG. 14;

[0033] FIG. 16 is a cross sectional view of the third preferred embodiment according to the present invention;

[0034] FIG. 17 is a partial top view of the base frame and corrugated steel floor of the container shown in FIG. 16;

[0035] FIG. 18 is a cross sectional view taken along the A-A line of FIG. 17;

[0036] FIG. 19 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;

[0037] FIG. 20 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;

[0038] FIG. 21 is a cross sectional view taken along the B-B line of FIG. 17;

[0039] FIG. 22 is a schematic diagram illustrating the connecting structure between the bottom cross members as shown in FIG. 19 and the corrugated steel plates in the container shown in FIG. 16;

[0040] FIG. 23 is a cross sectional view illustrating a kind of corrugated steel plate with stuffing in its grooves in the third preferred embodiment according to the present invention;

[0041] FIG. 24 is a cross sectional view illustrating another kind of corrugated steel plate with thin plate paved on it in the third preferred embodiment according to the present invention;

[0042] FIG. 25 is a partial perspective view illustrating floor structure in the third preferred embodiment according to the present invention;

[0043] FIG. 26 is a perspective partial cross sectional view illustrating the continuous corrugated steel floor with stuffing in its grooves in the third preferred embodiment according to the present invention;

[0044] FIG. 27 is a perspective partial cross sectional view illustrating the disconnected corrugated steel floor with stuffing in its grooves in the third preferred embodiment according to the present invention;

[0045] FIG. 28 is a partial top view illustrating the base frame and plane steel plate in the fourth preferred embodiment according to the present invention;

[0046] FIGS. 29, 30, 31, 32 are schematic diagrams of different kinds of base frames in the fourth embodiment according to the present invention;

[0047] FIG. 33 is a schematic diagram illustrating a kind of connecting structure between the longitudinal members, supporting beams and bottom cross members in the fourth embodiment according to the present invention.

[0048] Embodiment 1:

[0049] In this embodiment, the improvements mainly concentrate on the base frame and floor of the container.

[0050] As shown in FIG. 8, the base frame according to this embodiment mainly comprises two bottom side rails 611, several longitudinal members 613 and several bottom cross members 612. The both ends of the bottom cross members 612 are respectively welded to the side of the bottom side rails 611, the longitudinal members 613 are crossed and welded to the bottom cross members 612, constituting an integral rigid frame structure. Compared to a conventional container, in the new design, several longitudinal members 613 are added in the base frame, and thinner plane steel plate is adopted in the floor. Therefore, on the premise of passing ISO test, the space L1 between two bottom cross members is far larger than that (L0, as shown in FIG. 2) of the conventional one, thus, the quantity of the bottom cross members are greatly reduced.

[0051] As shown in FIG. 8 and FIG. 9, at least two longitudinal members 613 are crossed and welded to some bottom cross members 612, and the longitudinal members 613 are distributed along the longitudinal direction of the bottom cross members 612. To enable the longitudinal members to pass the ISO test with a small sectional area H2, B2 and thinner thickness T2, space L2 between the longitudinal members should be no larger than 600 mm, better preferred to be no larger than 300 mm, and best preferred to be equal to the width of the floor test wheel 400 of a container, which is 180 mm, so than at least one longitudinal member will directly support the floor test wheel 400. In addition, the space L1 between the bottom cross members 612 should not be made too large, and should be reasonably designed.

[0052] Various link structures can be adopted for the longitudinal members 613 and the bottom cross members 612. Two kinds of representative link structures are given below:

[0053] As shown in FIG. 10, some slots 614 with openings are made on the bottom cross members 612 in regular interval, the entire longitudinal members 613 can pass through slots 614 and be welded to the bottom cross members 612.

[0054] As shown in FIG. 11, the longitudinal members 613 are disconnected and then welded to the bottom cross members 612.

[0055] In the structures described above, both the bottom cross members 612 and the longitudinal members 613 can be made of steel bars whose cross section can be L-shape, I-shape, T-shape, U-shape, C-shape or square shape.

[0056] In this embodiment, the floor is made of steel plate 510 no thicker than 4 mm. As shown in FIG. 13, the bottom cross members 612 of the base frame and the steel plate 510 are connected by welding. As shown in FIG. 9 and FIG. 12, the bottom side rails 611, longitudinal members 613, bottom cross members 612 and the steel plate 510 are welded together, constituting an integral rigid bearer for cargoes in the container.

[0057] This invention has following advantages:

[0058] (a) The height H1 of the bottom cross members 612 is larger than that (H0, as shown in FIG. 4) of a conventional one, which enables the material distribution of the bottom cross members more advantageous for increasing the bending resistance of the bottom cross members.

[0059] (b) Since the bottom cross members 612 and the steel floor 510 are welded into an integral structure, the materials around the spot where the steel floor 510 and the bottom cross members 612 are welded will greatly improve the bending resistance of the bottom cross members.

[0060] Therefore, on the premise of passing the ISO test, the thickness T1 of the bottom cross members 612 according to this embodiment is thinner, normally it is 2 3 mm, while the thickness TO of the conventional bottom cross members 602 is thicker, normally it is 44.5 mm. In this embodiment, the bottom cross members 612 have similar base width B1, higher height H1, and comprehensively lighter weight as compared to that of the conventional one.

[0061] The steel floor is made of common steel. Compared to conventional plywood floor, it has advantages such as light weight, low cost and stable market supply. On the premise of passing the ISO test, in the new designed base frame, the quantity and the tare weight of the bottom cross members are reduced. Moreover, in the new design, since steel floor is adopted instead of plywood floor, the material cost is decreased. Besides, by using steel floor instead of conventional plywood floor, the influence to the production and cost of the container from the possible shortage of the wood supply can be avoided.

[0062] Embodiment 2:

[0063] In this embodiment, the improvements mainly concentrate on the structure of the side panels of the container.

[0064] To pass the ISO strength test for the side panels of the container, the corrugated plate for the side panels should possess certain bending resistant capability, which depends on the bending resistant section modulus W of the corrugated plate and the yield strength of the corrugated plate material. The larger the bending resistant section modulus W is, the better the bending resistant capability of the corrugated plate is. So it is with the yield strength.

[0065] In the conventional container, the corrugation depth (wave height) D of the corrugated plate is too small, and the projection length I of the slope on wave crest plane is too high, which is not advantageous for material to be thoroughly distributed in wave crests and troughs on the corrugated plate, and results in small bending resistant section modulus W. Therefore, Therefore, thicker steel sheet and higher strength material need to be used in the conventional corrugated plate to pass ISO strength test.

[0066] As shown in FIG. 14 and FIG. 15, on the premise of meeting the ISO standard dimension requirement for the container, the corrugation depth D of the corrugated plate is increased and the projection length I of the slope on the wave crest plane is reduced, so as to appropriately increase the width B of wave crest and the width C of the wave trough, improve the material distribution in wave crests and troughs, and thereby to improve the bending resistant section modulus W of the corrugated plate. In this way, the corrugated plate for the new side panel is equivalent to the corrugated plate of the conventional side panel in bending resistant strength, thus achieving the end of substituting expensive, high strength material with cheap, low strength material, reducing material cost, corrugated plate thickness and tare weight.

[0067] The corrugation depth D of the corrugated plate for the new side panel is 36<D54 mm projection length I of the slope in the wave crest plane is 0I25 mm, which is better preferred to be within 12-15 mm, and the thickness of the side panel is within 0.8-1.2 mm.

[0068] A comparison of dimension and material of corrugated plates for the conventional side panel and two examples of this embodiment is given in the table below:

	Corrugation dimension mm	Corrugated plate
	Thickness	material
			Corrugation		T of		Yield
Corrugation shape	Wave	Wave	depth		Corrugate		strength
and material	crest B	trough C	D	Slope I	d plate	Material	Kg/mm2
Conventional	72	70	36	68	1.6	Corten	35
corrugated plate						A
New	P1	78	78	38	15	1.2	SS41	25
corrugated	P2	78	78	45	12	1	SS41	25
plate

[0069] It can be seen from the data in the table, the slope projection length I of the corrugated plate for the conventional side panel is too big 68 mm, while corrugated depth D is comparatively small 36 mm. To pass ISO test, the thickness T of the corrugated plate has to be at least 1.6 mm and steel sheet Corten A of relatively higher strength yield strength 35 Kg/mm² has to be used.

[0070] The corrugated plate P1 for the new side panel appropriately increases wave crest and wave trough size by adding the corrugated plate depth D 38 mm and reducing the slope size I 15 mm. The corrugated plate made of lower strength steel sheet SS41 yield strength 25 Kg/mm² and 1.2 mm in thickness T is good enough to provide equivalent bending resistant strength as the corrugated plate for the conventional side panel.

[0071] The corrugated plate P2 for the new side panel appropriately increases wave crest and wave trough size, by adding corrugated plate depth D 42 mm and reducing slope dimension I 12 mm. The corrugated plate made of lower strength steel sheet SS41 yield strength 25 Kg/mm² and 1 mm in thickness T is good enough to provide equivalent bending resistant strength as the corrugated plate for the traditional side panel.

[0072] It can be seen that, by adjusting the wave depth D and the projection length I of the slope on the wave crest plane, the corrugated plate for the new side panel can achieve the end of substituting high strength material with low strength material, reducing the material cost of the container, the thickness of the corrugated plate, the weight of the container and improve the maximum pay load of the container.

[0073] Embodiment 3:

[0074] In this embodiment, the improvements mainly concentrate on the floor structure of the container.

[0075] As shown in FIG. 16, the container according to this embodiment 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.

[0076] As shown in FIGS. 17, 18, 21 and 22, 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.

[0077] 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.

[0078] 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:

[0079] As shown in FIG. 19, 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.

[0080] FIG. 20 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 installed 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.

[0081] 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.

[0082] Compared to the prior art, the base assembly of this embodiment possesses following advantages

[0083] (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.

[0084] (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 enhanced.

[0085] (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.

[0086] 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 44.5 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.

[0087] 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

[0088] As shown in FIG. 23, 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.

[0089] As shown in FIG. 24, 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.

[0090] 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:

[0091] As shown in FIG. 25, 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.

[0092] As shown in FIG. 26, which is a partial enlarged view of FIG. 25, 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.

[0093] As shown in FIG. 27, 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.

[0094] As shown in FIG. 25, FIG. 26 and FIG. 27, 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.

[0095] 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.

[0096] Alternatively, the steel floor according to this embodiment 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.

[0097] Embodiment 4:

[0098] In this embodiment, the improvements mainly concentrate on the base frame of the container.

[0099] As shown in FIG. 28 and FIG. 29, in a kind of structure of this embodiment, there is one or several longitudinal members 340 vertically installed between the bottom cross members 240, and there are supporting beams 440 tilted installed at the corner of the cross made up by the longitudinal members 340 and the bottom cross members 240. And the distribution intensity of the supporting beams 440 may be varied in different position of the base frame according to the actual loading situation of the container. Compared with the conventional base frame of the shipping container, one or several longitudinal members 340 and tilted supporting beams 440 are added in the base frame. Therefore, with the base frame strength requirement fulfilled, the space L1 between two cross members of the base frame may be far larger than that (L0) of the conventional one. Thus, compared with the conventional container base frame, the numbers of the cross members 240 are greatly reduced.

[0100] As shown in FIG. 30 and FIG. 31, in another kind of structure of this embodiment, longitudinal beams 340 are shorter than bottom side rails, and vertically installed between adjacent or non adjacent bottom cross members 240. Conventionally, manufacturer installed a whole length of longitudinal beam on the base frame, the whole length of the longitudinal beam is in parallel with and of the same length as the bottom side rail 140; while in this embodiment, the habitual thought is broken through, the longitudinal beam is installed in segment regularly or irregularly, namely, distributed non continuously.

[0101] In another kind of structure of this embodiment, only one end of the bottom cross member is connected with the bottom side rail, and the other end is connected with the longitudinal member. As shown in FIG. 32, one end of several bottom cross members 240 are disconnected from the two bottom side rails 140 crisscross, each longitudinal member 340 is connected in parallel between more than two disconnected bottom cross members 240, the internal point of the longitudinal member 340 is connected with the disconnected end of one bottom cross member 240, while the two ends of the longitudinal member 340 are connected with the internal point of the bottom cross member 240.

[0102] The longitudinal members 340 and the bottom cross members 240 are jointed by crossing, and the embodiments of the crossing structure may be various. Apart from the two kinds of commonly used crossing structures described in embodiment 1 of this invention, another kind of connecting structure may be adopted as shown in FIG. 33: several beams 240, 340, 440 are jointed together at one connecting point.

[0103] In the above mentioned container base frames, the bottom cross members 240, longitudinal members 340 and tilted supporting beams 440 may be made of steel beams with the cross sections such as L shape, I shape, T shape, U shape, C shape or square shape. In order to save material, the cross section of the longitudinal members 340 should be less than that of the bottom cross beams 240, and the longitudinal members are usually made of beams with smaller thickness and width.

[0104] Comparing to the conventional design, the container base frame according to this embodiment has other advantages as follows:

[0105] a. The height H1 of the bottom cross members 240 is higher than that of the conventional one, which makes the cross section material distribution of the bottom cross members 240 more favorable for increasing its bending resistance;

[0106] b. The bottom cross members 240, the longitudinal members 340, the supporting beams 440 and the steel floor 540 are welded together into an integral entity, which makes the strength of the materials around the welding area increased, and the bending resistance of the base frame is greatly improved;

[0107] The steel floor is made of common steel. Compared with conventional plywood floor, it has advantages such as lightweight, low cost and stable supplies from the market. On the premise of passing ISO test, in the new container base frame, the quantity of the bottom cross members used is reduced, the longitudinal members can be installed with more flexibility and the dimension of its cross section is smaller. Therefore, the material consumed is greatly reduced and the material cost of the new type container base frame is reduced compared with that of the conventional one. In addition, the conventional plywood floor is replaced by the steel floor, which prevents the influence to the production and cost of the container from the possible shortage of plywood floor supplies. With the application of the container base frame and the steel floor according to this embodiment, the targets of reducing material cost and tare weight of a container, and increasing its loading capacity are successfully achieved.