DK2881339T3

DK2881339T3 - Container and method of making a container

Info

Publication number: DK2881339T3
Application number: DK14196241.5T
Authority: DK
Inventors: Thomas Berger
Original assignee: Muhr & Bender Kg
Priority date: 2013-12-04
Filing date: 2014-12-04
Publication date: 2017-10-30
Also published as: ES2643023T3; EP2881339B1; CN104690187B; DE102013224924B4; EP2881339A3; DE102013224924A1; SI2881339T1; EP2881339A2; CN104690187A; PL2881339T3

Description

The invention relates to a container as well as to a method for manufacturing such a container. Containers are large capacity boxes, which serve for storing or for transporting objects or materials.

So-called ISO-containers are used for the sea freight. ISO-containers are standardised large capacity containers made from steel and which enable a simple and fast loading, transportation, storage and unloading of goods. Containers for air freight, rail freight and road freight are also known, which generally are also standardised.

An ISO-standard container for sea freight has in most of the cases a length of twenty or forty feet, which corresponds to an approximate length of 6 or 12 meters. The width is 2350 mm. It is differentiated between containers with different heights, i.e. with a standard height of approximately 2395 mm and with a larger height of 2700 mm, wherein the latter are also designated as so-called “High Cube”.

The containers are manufactured from metal sheet with mostly a width of 1500 mm. Several sheet metal blanks are welded to form an assembly group. In this case, it can happen, that for example for the side wall, metal sheets with different wall thickness are welded to each other, to meet the differently strong loading at the corner posts and in the centre of the side wall.

Containers for sea freight are generally manufactured from weather-resistant construction steel, which is also designated as Corten-steel or COR-TEN-steel. In special cases, containers are, however, also manufactured from stainless steels or other metals. The designation COR-TEN was constructed from the first syllable “COR” for Corrosion Resistance and the second syllable for Tensile Strength. Weather-resistant construction steels are steel alloys with alloying additives like copper, phosphor, silicium, nickel and/or chromium. They form on the surface a specially dense barrier coating made from firmly adhering sulphates or phosphates, which protect the component against further corrosion.

From CN 203186913 U a container with an end wall and side walls is known. The end wall and the side walls are composed of several individual vertically extending sheet metal elements. The sheet metal elements have a variable sheet thickness over the width of the respective element. A similar container is known from FR 2 125 109 A1, which has individual corrugated panels. The panels have a variable thickness in the transverse direction of the wave profile.

For US 4 795 049 B an open-top container is known with a bottom and side walls. The side walls include a sliding connection of overlapping two upper panels that overlap a single lower panel. Fastening elements are penetrated through long holes in the upper panels for fixing, so that a limited displacement movement between the upper panels is possible in order to distribute the compressive forces acting on the panel.

From US 4 685 721 B, a trailer construction with a floor, a roof and side walls is known. The side walls comprise groups of plates of light metal. A first group of plates has a greater thickness than a second group of plates. The groups of plates are arranged in the side walls in such a way that a high stiffness is obtained. Connecting panels of metal are fixed to the outer side of the side walls, in order to connect two adjacent plates to each other and to increase their strength.

From CN 202244878 U, a container with a bottom cross beam is known. The bottom cross beam has a cross-section C-shaped profile. A reinforcing plate with an L-shaped or C-shaped profile is provided on an inner surface of the profile.

From CN 202440020 U a similar container is known with a bottom cross beam having a C-shaped cross-section. Reinforcement parts with an L-shaped or C-shaped cross-section are provided at an inner face of the cross beam.

From CN 201165407 Y a bottom beam for a container is known. The bottom beam has an l-shaped cross-section profile. A base portion of the l-shaped beam has a thickness of 3.2 mm, while a centre portion of the l-shaped beam has a thickness of 2.5 mm.

From US 2010 0205902 A1 a topside beam is known for a container, which is composed of two beam elements, which are connected to each other at flange portions by means of connection members. The beam elements have, when seen in cross-section, portions with variable wall thicknesses.

From DE 44 42 208 A1 a transport container is known with side walls, a bottom member formed as a hollow beam, and a top member formed as a hollow beam. The bottom member and the top member have a larger sheet thickness than a wall face of the container arranged therebetween.

From DE 195 40 659 A1 a transportation container with a multitude of vertical elements is known, which form a wall of the container. The vertical elements are provided with reinforcement plates, which shall protect the other wall portions, made from thinner steel sheets, against mutual contact with a neighbouring container.

From DE 10 2010 032 309 A1 a freight and storage container according to the ISO-standard made from fibre-reinforced plastics and their compound materials is known.

From DE 100 41 280 A1 a method and a device for flexible rolling a metal strip is known. The metal strip is guided through a rolling gap, formed between a first working roll and a second working roll for the rolling process. The dimension of the rolling gap is varied such, that along the length of the metal strip, strip portions with larger strip thickness and strip portions with smaller strip thickness are achieved.

From DE 198 46 900 A1 a method and a device for producing a metal strip for being cut to blanks. In order to obtain the blanks, the hot-rolled strip is cooled or heated in sections, so that with a constant rolling force the strip undergoes a different thickness reduction. A disadvantage in containers is their high tare weight. For example the empty weight of a sea container with a length of 20 feet is approximately 2,200 kg. This high weight has negative effects on the displaced water mass and, thus, on the fuel consumption and the draft of the ship. Furthermore, also the loading capacity is influenced by the empty weight of a container.

The present invention is based on the object, to propose a container, which has a low empty weight with at the same time high stability and which can be simply and cheaply manufactured. The object is, further, to propose a method for manufacturing such a container. A solution is a container comprising carrier members and panels, wherein at least one element of the carrier members and of the panels is produced from metal sheet with a variable sheet thickness along the length such that end portions of the element comprise a greater sheet thickness than at least one portion arranged therebetween; and wherein the element comprises a formed region that extends in the longitudinal direction of the element.

An advantage is, that individual elements of the container can be adapted individually concerning the material thickness along the length of the respective element to the requirements concerning strength and stiffness. The dimensioning of the individual portions of the elements can be individually carried out in dependency of the respective loadings, so that an over-dimensioning of the elements and thus of the container is reduced. Material can be saved by means of targeted reduction of the thickness of the elements in low loaded areas, so that the container has overall a low weight without losses concerning the mechanical characteristics and thus can cheaply be manufactured.

By means of reduction of the weight, fuel can be saved during the later transport of the container, which leads to savings in cost for operation and an improved environmental balance. In containers, which are loaded up to the loading limit, like for example cooling- or tank containers, a potential is achieved for increasing the loading by means of reduced empty mass of the container. The maximum sheet thickness of the elements is determined by the local loading, mainly during loading or transportation. Most components of the container have a potential for the weight optimisation, as not all points of an assembly group are loaded to the same extent and, thus, can be locally dimensioned with a lower wall thickness.

At least one element of the carrier members and of the panels means, that at least one of the carrier members and/or at least one of the panels of the container are made from sheet metal with variable sheet thickness along the length. Sheet metal means a rolled flat product, which is manufactured from a metal, for example from a steel material or a light metal, like aluminium or an aluminium alloy. The length or the longitudinal direction of the sheet is, in the present case, defined as the direction, along which the thickness changes. This means, the portions of uniform thickness extend transversally to the longitudinal direction of the sheet metal or the element manufactured therefrom. The length of the sheet or of the element manufactured therefrom means especially the longest extension along an edge of the respective element or a partial portion of the element. The term carrier member shall embrace all frame members of the container, especially bottom cross members, bottom side members, bottom end members, vertical members, top cross members and/or top side members, without being limited thereto. The term panel shall embrace all elements, which are connected to the carrier members and close or encase the container to the outside, like especially side walls, end walls, doors and/or a roof of the container.

The carrier members comprise at least bottom cross members and bottom side members, wherein end portions of the bottom cross members have, preferably, a larger sheet thickness than at least one portion of the respective bottom cross member arranged between the end portions. This at least one thinner intermediate portion can be arranged at any position between the end portions. A first end of the bottom cross member is connected to the first bottom side member and the opposite second end of the bottom cross member is connected to the second bottom side member. By means of the larger sheet thickness in the end portions, a secure connection between the bottom cross member and the bottom side members is produced with a high strength. The end portions with larger sheet thickness can have a width of 20 mm up to 40 mm. The sheet thickness in the end portions is, preferably, between 3.0 mm and 5.0 mm, especially between 3.5 and 4.5 mm. One or more portions with lower sheet thickness can be provided between the end portions. These can have a sheet thickness of 1.0 mm up to 2.5 mm, especially between 1.3 mm and 2.0 mm. The embodiment with one or more bottom members with variable sheet thickness along the length is especially advantageous since, as the case may be, it can be done without separate reinforcement elements.

When using larger loads or a low number of bottom cross members, these can, however, be provided with reinforcement elements, which, when seen in cross-section, are arranged between a first profile portion and a second profile portion, wherein the bottom cross member has in the area of the reinforcement elements a larger sheet thickness than in the area between two neighbouring reinforcement elements. In this case, the above named preferred thickness ranges can be used. It is understood, that the specified thickness profiles of the named components can also be modified depending on the requirements. Especially, for other containers than for sea freight, other thickness profiles can be applicable.

The carrier members comprise in particular also four vertical members, which can also be designated as corner posts. The vertical members have, respectively, an upper end portion, which is connected to an upper corner fitting, and a lower end portion, which is connected to a lower corner fitting. Preferably, the upper and/ or the lower end portions have a larger sheet thickness than at least one intermediate portion of the respective vertical member arranged therebetween. A secure connection to the corner fitting with a high strength is achieved by means of the increased sheet thickness at least at one of the end portions. The connection is, preferably, achieved by welding, wherein other connection methods are not excluded. The sheet thickness profiles named in connection with the bottom cross members preferably also apply for the sheet thickness profiles of the vertical members.

The panels comprise at least one wall, which can be formed as an end wall and/or side wall. The wall has at least one wall element made from sheet metal with a variable sheet thickness, which is built in such, that the wall has a variable wall thickness along the height of the wall. In particular it is provided that the thickness of the at least one wall element varies along the length of the wall element, i.e. in the longest extension of the wall element. The wall element has an upper end portion, which is connected to a top carrier member, and a lower end portion, which is connected to a bottom carrier member. Preferably, the upper and/or the lower end portions have a larger sheet thickness than at least one portion of the wall element arranged therebetween. This thinner intermediate portion can be arranged at any position between the two end portions. The end portions with larger sheet thickness can have a width of 20 mm up to 200 mm, wherein also smaller widths of down to 40 mm are possible. The sheet thickness is, preferably, between 1.5 mm and 2.5 mm at the end portions. One or more portions with smaller sheet thickness can be provided between the end portions, which includes the possibility, that also one or more thicker portions can be formed between the end portions. The sheet thickness of the thinner portions is, preferably, between 1.2 mm and 1.8 mm.

According to an alternative embodiment, the wall element can have a centre portion with larger sheet thickness, which are followed by intermediate portions with smaller sheet thickness. The sheet thickness of the centre portion can be larger than that of the intermediate portions and/or larger than that of the end portions. Preferably, the centre portion has a sheet thickness of 1.8 mm up to 2.5 mm. The extension of the centre portion can be between 300 mm and 500 mm in longitudinal direction of the wall element. An unwished plastic deformation of the wall is reduced or prevented by means of the thickened centre portion.

The panels can comprise a roof, which has at least one roof element made from sheet metal with a variable sheet thickness along the length of the roof element, wherein the roof element has end portions for connecting to a respective top side member, wherein the end portions have, respectively, a larger sheet thickness than at least one intermediate portion of the roof element arranged between the end portions. Depending on the size, the roof can be composed of several individual roof elements, which initially are, respectively, separately manufactured and then welded to each other along their lateral longitudinal edges. In this case, the thickened end portions of the roof elements form the side regions of the roof, which are connected to the left and right top side rails.

According to a preferred embodiment, the roof has at the front and rear ends of the container first roof elements made from sheet metal with a variable sheet thickness along the length, which have at least in the corner portions a larger sheet thickness than second roof elements, which are arranged in longitudinal direction of the container between the front and rear end-sided first roof elements. For the end-sided first roof elements and for the second roof elements arranged therebetween, preferably, at least one of the following applies: the end portions of a first roof element have a larger sheet thickness than at least one intermediate portion of said first roof element; and/or the end portions of a first roof element have, respectively, a larger sheet thickness than the end portions of the second roof element; and/or the intermediate portion of a first roof element has a larger sheet thickness than the at least one intermediate portion of the second roof element. By means of the embodiment with thicker first roof elements at the front and rear end sides, an especially high stability is achieved herewith in an advantageous manner, so that a damage of the container can be prevented when inaccurately stacking another container on top.

According to a preferred embodiment at least one of the carrier members is recrystallized at least in portions with lower sheet thickness. The recrystallisation is carried out especially by means of heat treatment (recrystallisation annealing). By means of recrystallisation, internal stresses in the sheet element are reduced and the sheet element receives a good deformability for a following forming process. If the carrier members are made from rolled or profile-rolled sheets, a work hardening caused by the rolling or profile rolling process is again cancelled or reduced. It is especially provided, that the sheet elements for manufacturing the bottom end members, the bottom cross members and/or the vertical members are recrystallized before the forming.

Preferably, at least one of the panels is work-hardened at least in portions with lower sheet thickness. This means that one or more sheet elements for producing an end wall, side wall, door or roof are subjected to no recrystallisation annealing after the flexible rolling or profile rolling, but are formed roll-hardened to the respective wall element. Strain-hardening refers to the strengthening of a metal that occurs by rolling or roll-profiling. The advantage of using panels that are at least partially strain-hardened is, that the respective wall element thus has a higher strength and, thus, a higher resistance against unwanted plastic deformation.

The above named object is further achieved by a method for manufacturing a container from carrier elements and panels, wherein at least one element of the carrier elements and of the panels is manufactured with the steps: producing a sheet element with a variable sheet thickness along the length such, that end portions of the sheet element have a larger sheet thickness than at least one portion of the sheet element arranged therebetween; forming the sheet element by means of forming processes, wherein a formed portion extends in longitudinal direction of the sheet element. The forming processes can comprise bending, edgeforming, deep-drawing profiling and/or pressing. For producing a carrier element especially bending or edge-forming operations are used, wherein the sheet element is, respectively, bent around a bending axis, extending in longitudinal direction of the sheet element, wherein other forming processes are not excluded. For manufacturing a panel, deep-drawing or pressing is used preferably, without being limited thereto.

With the method, containers can be produced in an advantageous manner, which are adapted concerning their material thickness to the requirements concerning loading. With an improved material utilization, the containers manufactured according to the invention can withstand the same or higher loadings as common containers with uniform material thickness, wherein the weight and, thus, the costs for manufacturing and operational costs can be reduced. All explanations made above in connection with the product according to the invention are also valid for the method, especially in view of the thickness profiles of the components, and vice versa of the method are also valid for the product. It is obvious, that further manufacturing steps can be introduced upstream, downstream or in-between. For example, before or after the forming process several individual sheet elements can be welded to each other, to form a larger panel component like a roof, a side wall or an end wall. A sheet element for manufacturing a carrier member or a panel part can be produced especially according to one of the following possibilities: flexible rolling of a strip material for producing a variable thickness along the length and subsequently cutting of the flexibly rolled strip material to a certain length to form separate sheet elements with at least two portions with larger thickness and at least one portion with lower sheet thickness; or roll forming of a strip material for producing a variable thickness along the width of the material and following cutting of the rolled sheet material to a certain length to form separate sheet elements with at least two portions with larger sheet thickness and at least one portion with lower sheet thickness; or providing a first sheet blank with a first sheet thickness and providing two second sheet blanks with a lower second sheet thickness, welding of the second sheet blanks to the first sheet blank at opposite ends of the first sheet blank.

With all three possibilities, a sheet element is provided, which has portions with different thicknesses, i.e. at least with two thicker portions an at least one thinner portion arranged therebetween. It is obvious, that the sheet elements, depending on the requirements of the component to be manufactured therefrom, can also have further thicker and thinner portions along the length.

By flexible rolling, strip material with substantially uniform sheet thickness is rolled out by changing the rolling gap during the process to a strip material with variable sheet thickness along the length. The portions with variable thickness, produced by flexible rolling, extend transversally to the longitudinal direction or to the rolling direction of the strip material. The strip material can again be wound to a coil after the flexible rolling in a simple manner and can be transferred to another position of the further processing, or it can be directly further processed, for example by means of cutting the strip material to individual sheet elements. Sheet elements produced by flexible rolling are also referred to as Tailor Rolled Blanks.

By roll forming, the sheet material, i.e. the strip material or the individual sheet elements, with essentially uniform thickness is rolled out by means of the outline of the rolls to a sheet material with variable thickness along the width of the material. The portions of variable thickness, produced by the strip profile rolling, in this case extend in longitudinal direction of the sheet material. By roll forming, which is also designated as contour roll forming, individual portions of the sheet material are stretched outwards. With both methods, flexible rolling and roll forming, the sheet material with variable sheet thickness is produced in one extension direction. Generally, it is also possible, to combine both processes, i.e. flexible rolling and roll forming, to produce sheet elements with wall thicknesses which are variable along the length and across the width. With this, the largest possible flexibility is achieved concerning the design of the thickness portions along the length and the width of the sheet elements for the container.

According to the third possibility, the sheet elements are constructed from several individual blanks with different sheet thickness and welded. Such sheet elements constructed from several partial blanks with different sheet thickness are also designated as Tailor Welded Blanks.

As a further method step, the sheet element for producing a carrier element or a panel for the container can be heat treated after rolling, especially by a recrystallisation annealing. However, a heat treatment after rolling can also be omitted, so that the sheet element is further processed in the roll-hardened condition to a carrier element or panel. A sheet element, which is not heat treated, has in the thinner portions a higher strength than in the thicker portions. Insofar a not-heat-treated sheet element for a container component is at the same time optimised concerning the thickness as well as concerning the strength.

Preferably, the sheet elements, which are further processed to a carrier member, are recrystallization annealed after the rolling and before the forming. The recrystallisation annealing is especially carried out such, that the portions with lower sheet thickness are recrystallised, while the portions with larger sheet thickness keep their microstructure or are not or only recrystallised to a small extent.

According to a preferred embodiment the sheet elements, which after the rolling are further processed to a panel, are not heat treated, but are formed in the roll-hardened condition. This has the advantage that the thinner portions of the sheet elements have, because of the previous rolling process, due to the strain hardening an increased strength than the thicker portions and thus, withstand in a better manner unwanted plastic deformations during use of the container.

The at least one carrier member can be any carrying component of the container, in particular a bottom cross member, including a bottom end member, bottom side member, vertical member, top cross member and/or top side member. The at least one panel can be for example a side wall element, end wall element, roof element and/or door element or can be formed to these. Respectively, one or more of the carrier members and/or of the panels can be produced according to the method.

Preferred embodiments are described in the following using the drawings. In these, it shows

Figure 1 a container according to the invention in a first embodiment in perspective view, with a roof made from panel elements with a material thickness, which is variable along the length,

Figure 2 the frame structure of the container of Figure 1 in perspective view,

Figure 3 the roof of the container of Figure 1 as a detail in a top view,

Figure 4 the profile course of the material thickness of a first panel element according to the section line IV- IV of Figure 3,

Figure 5 the profile course of the material thickness of a second panel element according to the section line V - V of Figure 3,

Figure 6 a container according to the invention in a second embodiment in a perspective view, with an end face made from panel elements with a material thickness, which is variable along the length,

Figure 7 a container according to the invention in a third embodiment in a perspective view, with a side wall made from panel elements with material thickness, which is variable along the length,

Figure 8 a panel element of the container of Figure 6 or Figure 7 in a longitudinal sectional view in a first embodiment,

Figure 9 a panel element of the container of Figure 6 or Figure 7 in a longitudinal sectional view in a second embodiment,

Figure 10 a container according to the invention in a further embodiment in a perspective view, with a vertical member with a material thickness, which is variable along the length,

Figure 11 a vertical member of the container of Figure 10 in a longitudinal sectional view,

Figure 12 a container according to the invention in a further embodiment in a perspective view, with a bottom cross member with a material thickness, which is variable across the length,

Figure 13 a bottom cross member of the container of Figure 12 in a longitudinal sectional view,

Figure 14 a container according to the invention in a further embodiment in a perspective view, with a bottom cross member with a material thickness, which is variable along the length,

Figure 15 a bottom cross member of the container of Figure 14 in a longitudinal sectional view,

Figure 16 a method for producing a container according to the invention in a first embodiment,

Figure 17 a method for producing a container according to the invention in a second embodiment, and

Figure 18 a method for producing a container according to the invention in a third embodiment.

Figures 1 to 5, which are described in the following together, show a container 1 according to the invention in a first embodiment. Such a container 1 serves for storage or transportation of items or materials and can also be designated as a high capacity container.

The container 1 has carrier members 2 and panels 2. The carrier members 2 are connected to each other via corner fittings 4 and form together a frame- or skeleton structure, which can be seen in Figure 2 as a detail. The carrier members 2 of the present container 1 comprise two lower longitudinal side members 21, 21’ (also designated as bottom side members), two lower end-sided transversal members 22, 22’ (also designated as bottom end members), several bottom cross members 25, 25’, four vertical members 23 (also designated as corner posts), two upper longitudinal side members 24, 24’ (also designated as top side members) and two upper end-sided transversal members 26, 26’ (also designated as top end rails or front/rear header). The named carrier members 2 form together with lower corner fittings 4 and upper corner fittings 4’ the box-shaped frame structure of the container 1.

The bottom side rails 21, 21’, which extend on both sides longitudinally to the container 1, and the two bottom end rails 22, 22’, which extend on the front and rear end of the container transversally to the bottom side rails 21,21 ’, form a lower frame for the base 5. Between the two bottom side rails 21,21’, several cross members 25 extend, which serve as an abutment for the base 5. The cross members 25 are rigidly connected with their opposite ends to the respective bottom side rails 21,2T, for example by means of welding. The base 5 comprises several base elements 6, which are put onto the bottom cross members 25 and are connected to the same. The base elements 6 can, for example, be formed as wooden panels, wherein also other elements like metal sheet elements may be taken into account.

The container 1 comprises as panels 3 two side walls 31, 31’ (only partially shown), which extend, respectively, between the lower and the upper side rails 21, 24; 2T, 24’ as well as the corner posts 23 of the respective side of the container 1. Furthermore, the panels 3 comprise an end wall 32 (only partially shown), which extends between the bottom end rail 22, the top end rail 26 and the corner posts 23. On the rear end side arranged opposite to the front end wall 32, doors are provided (not shown), which are butted to the respective corner posts 23 and enable an access to the inside of the container. The roof 33, which is shown in Figure 1 in a position lifted from the upper frame, forms a further part of the panels 3 of the container 1.

According to the invention, it is provided, that at least one element of the carrier members 2 and of the panels 3 are made from sheet metal with a variable sheet thickness along the length of the respective element, especially from sheet steel. As material for manufacturing the container elements, preferably a weather resistant construction steel, like COR-TEN-Steel is used, wherein the use of stainless steel or other materials or metal alloys is also possible.

In the present embodiment according to Figures 1 to 5, the roof 33 comprises several sheet elements 71, 72 with variable thickness along the length of the respective sheet element. A projection of the end face of the roof 33 is shown in Figure 1 at the end of the arrows. Further details of the roof can be taken from Figure 3, which shows a top view of the roof, as well as Figures 4 and 5, which show cross-sectional views through the roof.

It can be seen, that the roof 33 is composed of several first roof elements 71 and several second roof elements 72, which are, respectively, initially separately manufactured and then welded to each other along their lateral longitudinal edges 73, 74. In this case, the longitudinal edges 73, 74 of the roof elements extend transversally to the longitudinal extension of the container 1. The roof elements 71, 72 have, respectively, thickened end portions 75, 75’; 76, 76’, which are to be connected to the top side rails 24, 24’, for example by means of welding, and thinner intermediate portions 77, 78 arranged therebetween.

The end-sided, i. e. front and rear first roof elements 71 have end portions 75, 75’ with a thickness D75 of preferably 6.0 mm up to 10.0 mm, especially approximately 8.0 mm and a width B75 of preferably 30 cm up to 50 cm, especially 40 cm, wherein the width relates to the longitudinal extension direction of the roof element 71. Between the end portions 75, an intermediate portion 77 is formed, which has a thickness of preferably 3.0 mm up to 5.0 mm, especially approximately 4.0 mm. Between the end portions 75, 75’ and the intermediate portion 77, transitional portions 79 with continuously changing sheet thickness are formed, respectively. The width B71 of the end-sided first roof elements 71 can be 70 cm.

The second roof elements 72, arranged in longitudinal direction of the container 1 between the end-sided first roof elements 71, each have end portions 76, 76’ with a thickness D76 of approximately 2.0 mm and intermediate portions 78 with a thickness of approximately 1.3 mm. Between the end portions 76, 76’ and the intermediate portion 78, continuous transitional portions are, respectively, formed. The width B76 of the end portions 76, 76’ of the second sheet elements 72 can be between 20 mm and 40 mm. The width B72 of the second roof elements 72 can be 70 cm or more.

The roof 33 has in the corner portions an especially large sheet thickness D75. In this case, an especially high stability is achieved in an advantageous manner, so that a damage of the container 1 during inaccurate stacking of a further container on top can be prevented. For a high strength of the roof 44, with at the same time good material utilization, it is valid: the sheet thickness D75 of the end portions 75, 75’ of the first roof elements 71 is larger than the sheet thickness D77 of the respective intermediate portions 77; the sheet thickness D75 of the end portions 75, 75’ of the first roof elements 71 is larger than the sheet thickness D76 of the end portions 76, 76’ of the second roof elements 72; and the sheet thickness D77 of the intermediate portion 77 of the first roof elements 71 is larger than the sheet thickness D78 of the intermediate portions 78 of the second roof elements 72.

Figures 6 to 9 show further embodiments for panels 3 of a container 1 according to the invention. The container 1 can, by the way, be formed according to the embodiment of Figures 1 to 5, to which description it is referred here. There the same or one another corresponding details are provided with the same reference numerals as in Figures 1 to 5.

Figure 6 shows a panel 3 in form of a side wall 31, which is composed of several sheet elements 81 with variable thickness along the length of the respective sheet element. Figure 7 shows a panel 3 in form of an end wall 32, constructed from several sheet elements 81 with variable sheet thickness along the length of the respective sheet element. The sheet thickness profile of the sheet elements 81 for the side wall 31 and of the sheet elements 81 for the end wall 32 can be formed identically or deviating from one another. The embodiments of Figures 6 and 7 can be realised individually or together on a container 1.

The side wall 31 of Figure 6, or the end wall 32 of Figure 7 are composed, respectively, of several sheet elements 81. The sheet elements 81 have respectively an upper end portion 82, a lower end portion 82’ and an intermediate portion 83 arranged therebetween, wherein the sheet thicknesses D82 of the upper and the lower end portions 82, 82’ are, respectively, larger than the sheet thickness D83 of at least one intermediate portion 83. Between the end portions 82, 82’ and the intermediate portion 83, respectively, continuous transitional portions 84, 84’ are formed. The individual sheet elements 81 are configured such, that a variable sheet thickness is realised in height direction of the container 1 from the variable sheet thickness in longitudinal direction of the sheet element in the assembled condition. The individual sheet elements 81 are initially manufactured separately and are, then, connected to each other at their longitudinal edges 85, 86, especially by means of welding. Several sheet elements 81, arranged upright and connected to each other, form, in this case, the respective side wall 31 or the end wall 32. Thus, the side wall 31 is constructed, in the present case, from five individual sheet elements 81, which can also be designated as wall portions, while the end wall 32 is constructed from only two individual wall portions 81.

The upper end portions 82 of the side wall 31 are connected to the top side rail 24, especially welded thereto, and the lower end portions 82’ of the side wall 31 are connected to the bottom side rail 21, especially by means of welding. Correspondingly, the upper and the lower end portions 82, 82’ of the end wall 32 are connected, especially welded, to the top end rail 26 or the bottom end rail 22.

Figure 8 shows a possible sheet thickness profile course in detail, as it is shown as a projection of the end faces of the walls in Figures 6 and 7 at the end of the arrows. The end portions 82, 82’ can have a width B82 of 20 mm up to 30 mm, especially of 25 mm, wherein the width relates to the longitudinal extension direction of the respective sheet element. The sheet thickness D82 is in the end portions 82, 82’, preferably, between 1.5 mm and 2.5 mm and can especially be 1.8 mm. The intermediate portion 83 can have a sheet thickness D83 of 1.2 mm up to 1.8 mm, especially 1.5 mm. Preferably, the sheet elements 81 are formed symmetrically in relation to a central cross-sectional plane, i.e. the dimensions of an upper half portion correspond to the dimensions of a lower half portion. The named dimensions can relate to the side wall 31 as well as to the end wall 32 of the container 1, wherein side wall and end wall can have in principle also thickness profiles deviating from one another, along the respective height of the respective wall.

Figure 9 shows a sheet thickness profile in an alternative embodiment in detail, as it would be achieved from the projections of the end faces of the walls in Figures 6 and 7 at the end of the arrows. The embodiment of Figure 9 corresponds to a large extent to that of Figure 8, wherein same or one another corresponding details are provided with reference numerals increased by the numerical value 10.

The end portions 92, 92’ can have a width B92 of 20 mm up to 30 mm, especially of 25 mm, wherein the width relates to the longitudinal extension direction of the respective sheet element. The sheet thickness D92 is in the end portions 92, 92’, preferably, between 1.5 mm and 2.5 mm and can especially be 1.8 mm. A special feature of the embodiment of Figure 9 is, that the individual wall elements 91 have, respectively, a centre portion 95 with larger sheet thickness D95, which is followed by the intermediate portions 93, 93’ with smaller sheet thickness D93. The centre portion 95 has a sheet thickness D95, which is larger than the sheet thickness D92 of the end portions. The sheet thickness D95 is, preferably, between 1.8 mm and 2.5 mm and can be especially 2.3 mm. The extension of the centre portion can be in longitudinal direction of the wall element 91 between 300 mm and 500 mm and is in particular 400 mm. The upper and lower intermediate portions 93, 93’, connected to a continuous transitional portion 94, 94’, have a thickness D93 of 1.2 mm up to 1,8 mm, especially 1.5 mm. By means of the thickened centre portion 95 an unwished plastic deformation of the wall constructed from the individual wall elements 91 is prevented in an advantageous manner. Also, in the present embodiment, the sheet elements 91 are formed symmetrically in relation to a central cross-sectional plane, i.e. the dimensions of an upper half portion correspond to the dimensions of a lower half portion.

The named embodiment can be used for the side wall 31 as well as for the end wall 32 of the container 1, wherein the side wall and the end wall can, in principle, also have thickness courses deviating from one another along the respective height of the respective wall. It is, especially possible, that the thickness profile of the wall elements 91 for the side wall 31 is formed according to Figure 9, while the thickness profile of the wall elements 81 for the end wall 32 is formed according to Figure 8.

Figure 10 shows a container 1 according to the invention in a further embodiment with vertical members 23, which are, respectively, manufactured from a sheet element with variable thickness along the length of the element. A projection of a side face of a vertical member 23 (corner post) is shown in Figure 10 at the end of the arrows. The sheet thickness profile is shown in detail in Figure 11. It is visible, that the vertical member 23 has, respectively, an upper end portion 42, a lower end portion 42’ and an intermediate portion 43 arranged therebetween. The upper end portion 42 is connected to an upper corner fitting 4’, while the lower end portion 42’ is connected to a lower corner fitting 4. The sheet thicknesses D42 of the upper and the lower end portions 42, 42’ are, respectively, larger than the thickness D43 of the intermediate portion 43. In this manner, a secure connection to the corner fittings 4, 4’ is provided. Especially, the sheet thicknesses D42 of the end portions can be between 4.0 and 5.0 mm and especially 4.5 mm, while the sheet thickness D43 of the intermediate portion 43 can be between 2.0 mm and 3.0 mm and especially 3.5 mm. Between the end portions 42, 42’ and the intermediate portion 43, respectively, transitional portions 44, 44’ with continuous thickness changes along the length of the sheet element are provided.

Figure 12 shows a container 1 according to the invention in a further embodiment with bottom cross members 25, which are manufactured, respectively, from a sheet element with variable thickness along the length of the element. A projection of a side face of a bottom cross member 25 is shown in Figure 12 at the end of the arrows. The sheet thickness profile is shown in detail in Figure 13. It is visible, that the bottom cross members 25 have, respectively, a first end portion 52, a second end portion 52’ and an intermediate portion 53 arranged therebetween. The first end portion 52 is connected to a first bottom side rail 21, while the opposite end portion 52’ is connected to the second bottom side rail 21 ’. The sheet thicknesses D52 of the first and the second end portions 52, 52’ are, respectively, larger than the thickness D53 of the intermediate portion 53. Because of this, a secure connection to the bottom side rails 21,21’ is ensured. Especially, the sheet thicknesses D52 of the end portions can be between 3.5 mm and 4.5 mm and especially be 3.6 mm, while the sheet thickness D53 of the intermediate portion 53 can be between 1.0 mm and 2.5 mm and especially be 2.0 mm. The length B52 of the thickened end portions can be between 20 mm and 40 mm. Between the end portions 52, 52’ and the intermediate portion 53, respectively, transitional portions 54, 54’ with continuous thickness change along the length of the bottom cross member 25 can be provided. In the present embodiment, all bottom cross members are formed identically to the profile shown in Figure 13. In Figure 12, two of the bottom cross members 25 are shown in the connected condition between the two bottom side members 21, 2T, while the other bottom cross members are shown in the unmounted condition.

Figure 14 shows a container 1 according to the invention in a further embodiment, which corresponds to a great extent to the embodiment of Figure 12. It is especially referred to the above description concerning the commonalities, wherein the same details are provided with the same reference numerals as in Figure 12. The panels 3 are not shown; they can have one or more of the above described embodiments or can be formed in a common manner. The first bottom cross members 25 shown in the mounted condition are formed like the bottom cross members of Figure 13.

The second bottom cross members 25’, which are shown in the unmounted condition, correspond to a great extent to the bottom cross members 25, so that concerning common features it is referred to the above description. Corresponding details are provided with reference numerals increased by the numerical value 10 as in Figure 13. In a modification to the embodiment of Figure 13, the bottom cross members 25’ have additional reinforcements 66, which extend in a cross-sectional view through the cross member between a first profile portion 67 and a second profile portion 67’ of the bottom cross member 25’. A projection of a side face of a bottom cross member 25’ is shown in Figure 14 at the end of the arrows. The sheet thickness profile is shown in detail in Figure 15. It is visible, that the bottom cross members 25’ have, respectively, between the thickened end portions 62, 62’ in the area of the reinforcements 66 a thickened intermediate portion 65, which alternates with the bottom side rails thinner intermediate portions 63. The end portions 62, 62’ are connected to the bottom side rails 21,2T.

The sheet thicknesses D22 of the end portions 62, 62’ and the thickness D65 of the thickened intermediate portion 65 are, respectively, larger than the thickness D63 of the thinner intermediate portions 63. Especially, the sheet thicknesses D22, D65 can be between 3.5 mm and 4.5 mm and especially be 4.0 mm, while the sheet thickness D63 of the thinner intermediate portion 63 can be between 1.0 mm and 2.5 mm and can especially be 2.0 mm. The length B62 of the thickened end portions can be between 2.0 mm and 4.0 mm. Between the end portions 62, 62’ or the thickened intermediate portions 65 and the thinner intermediate portions 63, transitional portions 64, 64’ are, respectively, provided with continuous thickness changes along the length of the bottom cross members 25’.

In Figure 16, a method according to the invention for manufacturing a sheet metal element for a container according to the invention in a first embodiment is shown.

In method step V1, the strip material 11, which is wound in the starting condition on a coil 12, is rolled, i.e. by means of flexible rolling. For this, the strip material 11, which has before the flexible rolling a more or less constant sheet thickness along the length, is rolled by means of rolls 13 such, that it receives longitudinally to the rolling direction a variable sheet thickness. During the rolling, the process is monitored and controlled, wherein the data, determined by a sheet thickness measurement, are used as input signal for controlling the rolls 13. After the flexible rolling, the strip material 11 has, respectively, portions 14, 14’ with variable thickness, extending transversally to the rolling direction. A portion of the strip material, which is rolled thick - thin, is shown as a detail in method step V1.

The strip material is wound again to a coil after the flexible rolling, so that it can be transferred to the next method step.

After the flexible rolling, the strip material wound to a coil, is heat treated in the method step V2, i.e. preferably by a recrystallisation annealing. The heat treatment can be carried out in a furnace 15. By means of heat treating, work hardenings of the material produced during the rolling are reduced or dissolved, and the rolled strip material 11 gains again a higher ductility and elasticity, so that it can easier be further worked in the following method steps, wherein, furthermore, the material characteristics of the to be manufactured end product are positively influenced. It is obvious, that the heat treatment in the method according to the invention is only optional, i.e. the strip material can, in principle, also be further worked without heat treatment.

After the heat treatment, the strip material 11 is smoothened in method step V3, which is carried out in a strip straightening device 16.

After the straightening, the strip material 11 is cut to individual sheet elements 17 in method step V4, which is done by means of a cutting device 18.

In method step V5, the sheet element 17 is formed by means of forming processes to a carrier member 25 for a container 1 according to the invention. In the present case, a bottom cross member 25 is shown as final product, wherein it is obvious, that a sheet element 17 produced according to the method can also be further worked to any other carrier member 2 or panel element 3 of the container by means of forming operations.

It is obvious, that the present method management can also be changed. For example, the sheet material with variable thickness along the length of the material can also be manufactured by means of roll forming instead of flexible rolling.

Figure 17 shows a method according to the invention for producing a sheet element from a strip material 11 according to a second method embodiment. This corresponds to a great extent to the method of Figure 16, so that concerning common features it is referred to the above description. In this case, the same details are provided with the same reference numerals as in Figure 16.

The method step V1 (rolling), V3 (straightening) and V4 (cutting to length) are identical to the corresponding methods steps V1, V3 and V4 of Figure 16. The difference to the method of Figure 16 is that, in the present case, after the flexible rolling (V1) and before the forming (V5) no heat treatment is carried out. This means, that the sheet material is further processed in a forming manner in a rolled-hardened or strain-hardened condition. This method embodiment is especially suitable for the manufacture of sheet elements, which should serve as panel elements for the container 1, like side walls, end walls or the roof. In the present case, a wall element 31 is shown exemplary as the final product. Also the method embodiment of Figure 17 can be changed such, that strip profiling rolling is used instead of flexible rolling for manufacturing the sheet material with variable thickness along the length.

The sheet elements 17, which are further processed to a carrier member, are preferably heat treated, i.e. such, that the portions with lower sheet thickness 14’ are recrystallised, while the portions 14 with larger sheet thickness essentially keep their microstructure. In contrast thereto, the sheet elements, which are further processed to panel parts, are preferably not heat treated, but remain in the roll-hardened condition.

Figure 18 shows a method according to the invention for producing a sheet element for a container 1 according to the invention in a third method embodiment. This differs from the method of Figures 16 and 17 such, that the sheet element 17’ is produced in method step V1’ by means of welding individual sheet blanks 18, 18’ with different sheet thickness to each other (instead of flexible rolling or strip profile rolling). A heat treatment of the sheet element 17 is not necessary before the process of forming the sheet to a wall element in method step V5’. The sheet element 17’ is visible as an intermediate product (Tailor Welded Blank) between the two method steps V1’ and V5’. In the present case, a roof element 33 is shown exemplary as the final product.

An advantage of the container 1 according to the invention or of the method according to the invention for manufacturing such a container is, that by means of targeted reduction of the thickness of the sheet elements in areas with low loading, material can be saved, so that the container 1 has a low weight without losses concerning the mechanical characteristics, which leads to a reduction of the costs during transportation. Especially in containers for sea freight, but also for air freight, rail freight and road freight, this leads to considerable fuel savings.

Reference numerals list 1 container 2 carrier member 3 panels 4 container corner fittings 5 base 6 base plate 11 strip material 12 coil 13 roll 14, 14’ portions 15 furnace 16 strip straightening device 17 metal sheet element 18 cutting device 21 bottom side member 22, 22’ bottom end member/rail 23 vertical member 24 top side member 25, 25’ bottom cross member 26, 26’ top end member/rail 31 sidewall 32 end wall 33 roof 42 end portion 43 intermediate portion 44 transitional portion 52 end portion 53 intermediate portion 54 transitional portion 62 end portion 63 intermediate portion 64 transitional portion 65 intermediate portion 66 reinforcement 67 portion 71 first roof element 72 second roof element 73 longitudinal edge 74 longitudinal edge 75 end portion 76 end portion 77 intermediate portion 78 intermediate portion 82 end portion 83 end portion 84 intermediate portion 85 longitudinal edge 86 longitudinal edge 87 transitional portion 92 end portion 93 intermediate portion 94 transitional portion 95 intermediate portion B width D thickness V method step

Claims

A container comprising carriers (2) and sheaths (3), wherein at least one element of the carriers (2) and sheaths (3) is made of plate having a variable plate thickness over the longest length of the element such that the end portion of the element has a greater plate thickness than at least one section lying therebetween and the element having a reshaped region extending in the longitudinal direction of the element.

Container according to claim 1, characterized in that the carriers (2) comprise bottom cross carriers (22, 22 ', 25, 25') and bottom length carriers (21, 21 '), wherein end sections (52, 52'; 62, 62 ') of the bundle crossbars (22, 22', 25, 25 ') has a greater sheet thickness (D52, D62) than at least one intermediate section (53, 63) of the bundle crossbeam in question.

Container according to claim 2, characterized in that the bundle crossbars (25 ') have, over the length, several reinforcing elements (66), as seen in the cross-section, between a first profile section (67) and a second profile section (67'), wherein 25 ') in the region of the reinforcing elements (66) has a greater plate thickness (D65) than in the region of two adjacent reinforcing elements (66).

Container according to one of Claims 1 to 3, characterized in that the carriers (2) comprise vertical carriers (23), wherein an upper end section (42) and a lower end section (42 ') of the vertical carrier respectively have a larger plate thickness (D42). than at least one intermediate portion (43) of the vertical carrier.

Container according to one of claims 1 to 4, characterized in that the linings (3) have a wall (31, 32) having at least one wall element (81, 91) of plate with a variable plate thickness over the length of the wall element, wherein the wall element (81, 91) has an upper end portion (82, 92) and a lower end portion (82 ', 92'), respectively, having a greater plate thickness (D82, D92) than at least one intermediate portion (83, 93) of the wall element .

Container according to one of claims 1 to 5, characterized in that the cover (3) has a roof (33) having at least one first roof element (71) of plate with a variable plate thickness over the length of the roof element, wherein the first roof element ( 71) has end portions (75, 75 ') for connecting to a roof length carrier (24, 24'), respectively, wherein the end portions (75, 75 ') respectively have a greater plate thickness (D75) than at least one between the end portions (75, 75'). intermediate section (77) of the first roof element (71).

Container according to claim 6, characterized in that the roof (33) has two roof elements (72) of plate with a variable plate thickness over the length of the roof element concerned, the two roof elements (72) having respective end sections (76, 76 ') for connecting to, respectively, one of the roof length carriers (24, 24 '), wherein at least one of the following applies: the end sections (76, 76') of the second roof element (72) have a greater plate thickness (D76) than at least one intermediate section (77) ) of said second roof element (72); the end sections (75, 75 ') of the first roof element (71) respectively have a larger plate thickness (D75) than the end sections (76, 76') of the second roof element (72); the at least one intermediate section (77) of the first roof element (71) has a greater plate thickness (D77) than the at least one intermediate section (78) of the second roof element (72).

Container according to one of claims 1 to 7, characterized in that at least one of the carriers (2) is recrystallized at least in sections with a smaller plate thickness.

Container according to one of claims 1 to 8, characterized in that at least one of the liners (3) is cold hardened at least in sections with a smaller plate thickness.

A method of manufacturing a container (1) of carriers (2) and sheaths (3), wherein at least one element of the carriers (2) and sheaths (3) is produced by: producing a plate element (17) having a variable plate thickness in a longitudinal direction in such a way that end portions of the plate element (17) have a greater plate thickness than at least one intermediate portion of the plate element; (17).

Method according to claim 10, characterized in that the reshaping comprises at least one of the processes bending, edging, depth drawing, pressing and profiling.

Method according to claim 10 or 11, characterized in that the plate element (17) is made by one of the following: flexible rolling (V1) of a strip material (11) to produce a variable thickness over the length and subsequent cutting (V4) of the flexible rolled strip material for individual sheet elements (17) having at least two sections having a larger sheet thickness and at least one section having a smaller sheet thickness; rolling profiling of a sheet material to produce a variable thickness across the width and subsequent truncation (V4) of the roll profiled sheet material for individual sheet members (17) having at least two sections having a larger sheet thickness and at least one section having a smaller sheet thickness; providing a first plate (18 ') with a first plate thickness and providing two second plate (18) with a larger second plate thickness, welding (V1') of the second plate with the first plate at opposite ends of the first plate.

Process according to one of claims 10 to 12, characterized in that, as a further process step before the conversion (V5) of the sheet material is provided: recrystallization annealing (V2) of the sheet material in such a way that the sheet material is recrystallized in section (14 ') with a smaller plate thickness.

Process according to one of claims 10 to 13, characterized in that at least sub-regions (14 ') of the sheet material are cold hardened in the manufacture of the variable thickness, in which the sheet material is cold-hardened in the coating element (3).

Method according to one of claims 10 to 14, characterized in that the plate element (17) is transformed into a bundle carrier (22, 22 ', 25, 25'), bottom length carrier (21, 21 '), vertical carrier (23), roof carrier ( 26, 26 ') or roof length carrier (24, 24') of the container, or the plate element (17) is transformed into a wall element (31,32), roof element (33) or door element.