CN1221448C - Palette container - Google Patents

Abstract

The invention relates to a palette container (10) comprising a thin-walled rigid inner container (12) made of thermoplastic synthetic material for storing and transporting liquid or flowable filling products. The inventive palette container also comprises a grid tube frame (14) which, as a support casing, closely surrounds the plastic container (12), and comprises a base palette (16) on which the plastic container (12) rests and to which the support casing is firmly attached. The grid tube frame (14) consists of vertical and horizontal tubular rods (30, 32) that are welded to one another at points of intersection (36). Several prior art palette containers exhibit substantial shortcomings (grid tube fatigue fracture) when subjected to prolonged dynamic vibrational stress that occurs, for example, during persistent stresses caused by the transport on roads of poor quality. The aim of the invention is to achieve an adapted optimal vibrational elasticity in order to improve the stability of the grid frame while providing a sufficient degree of flexural strength. To this end, the tubular rods (30, 32) have a closed profile (18) with a particular trapezoidal cross-section.

Description

pallet container

technical field

The present invention relates to a pallet container having a thin-walled inner container made of thermoplastic material for storage and transport of fluids or free-flowing goods, wherein the plastic container is tightly surrounded by a cage-shaped outer casing and a base pallet, said The cage-shaped casing is composed of intersecting pipe rods as a support shell, and the thermoplastic container is supported on the base pallet, which is firmly connected to the support shell.

Background technique

As for example in EP 0 734 987 A (Sch) generally known pallet container of this kind of pipe support sleeve with welding. The disclosed stem support sleeve of the pallet container consists of circular profiled stems which are highly compressed at the welded intersection points. Another pallet container is known from DE 297 198 30 U1 (vL) which has a different cross-section construction pipe rod, but its cross-section is obviously the same over the entire length of the rod, without any dents or caused An indentation with a reduced cross section. Another kind of pallet container with cage is known from DE 196 42 242, wherein the cage has an open profile pipe rod. Wherein, the straight faces of the laterally outward folded edges are welded together in the region where the cage bars intersect. Due to their thickness and sharp-edged outer flanges, open profile cage bars have little torsional stiffness and make palletized containers difficult to handle by hand. Furthermore, various pallet containers with cage rods of rectangular cross-section are also known in the prior art.

The attachment of the cage casing to the base pallet can be constructed as a flat pallet made of plastic or wood or as a steel frame and is usually by means of attachment such as screws, brackets engaging the lower horizontal and circumferentially extending cage rods , clip or hook closure implementation. These attachments are either nailed, riveted, screwed or welded to the top plate or upper outer edge of the pallet.

For industrial use or when pallet containers are used in the chemical industry, they must pass government approval inspections and meet various quality controls. For example, a full pallet container has to withstand the internal pressure test and the impact test from a specified height. Pallet containers or combination-IBCs of the type described here (IBC=Intermediate Bulk Containers) are advisable for transporting liquids. Especially when transporting filled combination-IBCs by truck, due to transport shocks and movements of the transport vehicle, especially on bumpy roads, considerable gushing movements of the liquid container contents can occur, resulting in a buildup on the inner container wall. A constantly changing pressure is applied, which in turn generates radial vibrations in the rectangular pallet container (dynamic continuous vibration stress). According to the construction of the cage jacket, during the long-term transportation on bad roads, stresses are gradually formed, which makes the cage rods fatigue and break. Accordingly, such pallet containers are not suitable for export to the United States, for example, or for multiple uses.

A disadvantage of the above-mentioned embodiment in EP 0 734 967 A is that the circular tube profiles of the horizontal and vertical cage rods, especially in the area of the intersection, are prone to considerable deformation, especially at the welding location, so that compared to other areas, The section modulus is significantly reduced. In addition, the pipe shank profile is recessed more deeply in the vicinity of the weld indentation, thereby further weakening the rod, whereby the material in the area of the recessed pipe shank profile becomes brittle by welding.

The object of the present invention is to avoid the above-mentioned disadvantages and to propose a pallet container with improved transport strength, which provides an improved resistance to transport stress, long-term vibration stress, with a device of simple construction. On the one hand, the pallet container should be suitable for transporting hazardous fluids or free-flowing loads up to the highest permissible level standard; on the other hand, it should be able to be constructed with fewer vertical and/or horizontal cage bars while meeting standard transport needs cage-shaped jacket without reducing its mechanical stability.

Contents of the invention

According to the invention, this object is achieved by providing a pallet container with a cage-shaped jacket consisting of vertical and horizontal tubular steel pipes, wherein the cage rods have a closed-profile trapezoidal cross-section with longer and shorter Side walls extending in parallel and two straight side walls extending obliquely to each other, the two straight side walls extending obliquely to each other from the longer side wall of the parallel side walls, connected to the shorter side wall, wherein the side walls extending obliquely to each other The two straight side walls form a top angle of about 20° to 45°, preferably about 36°. The trapezoidal closed profile of the pipe stem has a high bending section modulus and a high torsional section modulus due to the slight slope of the profile side walls to each other. This is particularly achieved when the aspect ratio (H/B) of the trapezoidal tube profile is in the range of 0.8 to 1.0, preferably about 0.86. With the pallet container according to the invention it is possible to achieve a cage casing which withstands the foreseeable standard transport stresses and which is constructed with a total of only 5 instead of 6 horizontal cage bars without a significant decrease in the mechanical load-bearing capacity .

In one embodiment of the invention, in the region where two cage rods intersect, the longer parallel side walls of the cage rods of trapezoidal profile are recessed inwardly along a length of about twice the width of the cage rods in such a way that the two The outer longitudinal edges form a convex surface such that four points are formed at each intersection of vertically and horizontally extending cage bars that are welded together securely, whereby the (longer) parallels at each cage bar intersection are opposite each other The walls do not touch each other even after welding.

In a preferred embodiment, the longer of the parallel walls of the trapezoidal profile cage rod is inwardly indented (= continuous longitudinal indentation or profiling) along its entire length in such a way that it forms a The two outer longitudinal edges of the extended convex surface (protrusion), wherein four points of contact are formed at each intersection of horizontally and vertically extending cage bars, these contact points are firmly connected after welding, so that after welding (relatively long) opposite parallel walls are spaced from each other and do not touch each other. Among the prototypes, the trapezoidal cage rods, which were recessed along their entire length, proved particularly outstanding in their use.

In a variant of embodiment, the longer parallel walls of the trapezoidal profile tube are indented inwards only partially in the intersection region, while the longer parallel walls of the other trapezoidal tube are indented inward along the entire length. This may be quite sufficient for average stress loads. The depth of the depression of the longer parallel wall is about one to two times the thickness of the formed pipe rod (about 1 mm to 2 mm); in the actual pallet container, the wall thickness of the formed pipe rod is 1 mm, and the recessed Depth A is also 1 mm so that after welding - whereby the crossing cage bar contact points melt into each other by about 1 mm - at each intersection the long parallel walls opposite each other are about 1 mm from each other and do not touch each other even after welding. This is particularly important since usually pallet containers are stored outdoors and thus exposed to the elements of the weather. By having spacing between the cage bars of the welding points, accumulated rainwater is easily drained and thus rust formation is substantially prevented. If the welding surfaces are in contact, rust will inevitably form, resulting in extensive rusting of the cage rods in a short period of time.

In another special design solution of the present invention, at least one indentation is provided on the side of the longer parallel wall of the trapezoidal pipe rod at a certain distance from each welding point. The indentation reduces the height H of the pipe stem, thereby relieving the critical peaks of dynamic vibration stresses and various bending stresses acting on sensitive welds. According to the invention, a dimple is provided on each side of the trapezoidal shank adjacent to the welding point at a distance of at least one tenth of the width B of the shank from the welding point. In this way, when dynamic vibration stress occurs, the critical tension peak is transferred from the welding point to the adjacent area at a certain distance from the welding point. The static or dynamic stresses acting on the welded connection are significantly reduced by this special construction, that is, the pipe stem has an indent at a transverse distance from the solder joint, thereby reducing peak stresses, where the solder joint is not in the deformation zone, thereby maintaining their high flexural strength. Compared with the known pipe rod profile and according to the invention, the pipe rod is not locally recessed at the welding point, but the individual indentations or indentations are located on the same and/or opposite side of the profile at a distance from the welding point, To reduce the flexural section modulus at the opposing intersections and relieve static and/or dynamic stress at the cage bar welds. The trapezoidal profile is configured so that it can be easily recessed without substantial material movement. Dimples (= indentations, or recesses, as desired to form "vibrating elements") of the pipe stem are provided only in specific areas of the pipe shape, thereby relieving vibration stresses acting on the welded intersections or four welded points and fluctuating bending tension peaks. When welding one pipe rod to a second pipe rod, tube hardening with embrittlement of the material takes place at this point, so that the pipe rod is particularly sensitive to vibrational stresses at this point. Considerable vibrational stresses, which are present during transport by truck, for example, can lead within a short time to fracture of the solder joints or to fracture of the pipe rod itself at the solder joints. According to the invention, the cage rod-support jacket is constructed such that the "desired vibration point" is not exactly located at the intersection or in the vicinity of the intersection, but at least has a certain short distance from the welding point at the intersection. The desired vibration point established by forming the dimples is in any case less than 50% of the cross-section of the pipe rod. They are arranged in the range of 10% to 45% of the cross-sectional height of the pipe stem, preferably about 1/3 (33%). Thus the flexural strength of the dimpled pipe rod is slightly reduced, but the susceptibility to fracture due to fatigue is greatly reduced.

Description of drawings

The present invention is explained and described in detail below with reference to the embodiments shown in the drawings. in:

Figure 1 is a front view of a pallet container according to the present invention;

Fig. 2 is the side view of test pallet container;

3 is an enlarged cross-sectional view of a trapezoidal pipe-rod profile at a pipe-rod intersection according to the present invention;

Fig. 4 is another enlarged sectional view of the preferred trapezoidal pipe profile at the intersection of pipe rods;

Fig. 5 is a schematic sectional view of the hydrodynamic pressure effect of the fluid load on the side wall of the container;

Figure 6 is a horizontal partial sectional view of the maximum point of cage outward deflection;

Figure 7 is an enlarged view of the intersection of pipe rods with dents;

Fig. 8 is the pipe rod trapezoidal cross-section according to the observation direction D of Fig. 7;

Fig. 9 is the trapezoidal cross-section of the pipe rod along the section line C-C in Fig. 7;

Fig. 10 is the rectangular profile of the unstressed pipe rod cross-section;

Fig. 11 is the rectangular profile of the cross-section of the overstressed pipe rod according to Fig. 10;

Fig. 12 is according to the stress-free pipe rod profile of the present invention;

Fig. 13 is a stressed pipe rod profile according to Fig. 12 according to the present invention;

Fig. 14 is another pipe rod profile according to the present invention;

Fig. 15 is another pipe rod profile according to the present invention;

Fig. 16 is a partial top view of the corner arc of the tubular surface according to the present invention.

Detailed ways

Shown in Fig. 1 and indicated by reference numeral 10 is a pallet container according to the invention, which shows a thin-walled blow-molded rigid inner container 12 made of thermoplastic material (HD-PE) with an upper inlet and a tight Surrounding the inner vessel is a cage 14 of intersecting pipe rods, wherein said cage is attached securely - but removably or interchangeably - to a base pallet 16 . The front view shown shows the narrow side of the pallet container 10 with the outlet valve arranged on the plastic container 12 close to the base. The outlet valve 18 is located above the lower front edge of the base pallet 16 shown here in construction as a wooden pallet (US Runner), said edge representing the most vulnerable point of the pallet container, during qualification tests, especially This edge is subjected to the greatest stress during the diagonal impact test. A special configuration of cage rods with dimples (see Figure 7) is shown in circles.

Before developing the pallet container according to the present invention, five different pallet containers known and commercially available were subjected to precise comparative stress tests (internal pressure test, impact test, vibration test, pressurization capacity test, respectively stacking capacity test). In a series of vibration tests simulating long-haul trucks traveling on bad roads, it was possible to isolate certain specific frequencies at which weak spots appeared in various rectangular jackets.

For testing purposes, the test pallet container 10 shown in Figure 2 (shown without elastic reinforcement indents) was also intentionally subjected to a continuous overload test, in which also circles show the marks marked on the horizontal and vertical cage bars. points, according to the dynamic vibration stress comparison test results (see Figures 10, 11), these points fail first and start to fracture.

FIG. 3 shows the intersection region of the closed tube-rod profile 18 according to the invention, a trapezoidal cross-section, a longer wall and a shorter wall 20, 22 extending parallel to each other and two straight walls 24 extending obliquely to each other , these two straight walls extend obliquely from the longer parallel wall 22 and are connected to the shorter wall 22, whereby the two straight side walls of the profile 18 extending obliquely to each other form an apex angle 26, the apex angle is between 20° and 45°, preferably about 36°. The aspect ratio of the pipe-stem trapezoidal profile is in the range of 0.8 to 1.0, preferably about 0.86. Due to the large height of the trapezoidal profile (no bending in the sloping side walls), a correspondingly high bending stiffness is achieved and due to the closed and compact construction of the trapezoidal profile Compared to the rod profile, the pipe rod exhibits improved torsional stiffness. The distance between the points of intersection of the horizontally elongated axes of the walls 24 extending obliquely to one another at an apex angle 26 is approximately the profile height H, or approximately 2H measured from the longer parallel wall 20 . The distance can be in the range of 0.75 to 2.5H.

A preferably used trapezoidal profile 18 is shown in FIG. 4 . In a simple manner, the longer parallel walls 22 are only partly inwardly recessed in the area where the two pipe stems intersect in such a way that an outwardly protruding convex surface 28 is formed on each of the two outer longitudinal edges so that Four contact points are formed at each intersection of horizontally and vertically extending pipe rods, which are firmly connected to each other after welding, whereby the (longer) parallel walls 22 facing each other at each pipe rod connection They are also separated from each other.

In a particularly preferred embodiment, the longer parallel walls 22 are inwardly concave throughout the length of the stem, thereby providing outwardly projecting convex surfaces 28 for the two outer longitudinal edges. A pipe rod with a trapezoidal profile 18 with continuous dimples proved to be outstanding and was manufactured with a pipe pattern having a diameter of 18 mm (circumferential length 56.55 mm). The indentation depth of the longitudinal profile should be approximately one or two times the wall thickness of the stem (approximately 1 mm to 2 mm); in a fully formed pallet container, the stem wall thickness is 1 mm and the indentation depth is 1 mm. Welding at each of the four contact points at each intersection of the pipe rods is accomplished by resistance pressure welding. When four-point welding is performed, the intersecting cage bars are pressed together by about 1mm so that the opposing parallel walls 22 at each intersection are still about 0.5mm to 2mm apart from each other even after welding, preferably about 1mm and do not touch each other. (distance A = 1 mm). This is very important because pallet containers are often stored outside and exposed to the weather. By spacing the cage bars from one another at the welding points, any rainwater that may accumulate there is dried by exposure to the air and thus rusting is substantially prevented. Welding surfaces that abut each other are inevitably prone to rust formation, which can lead to severe rusting of the entire cage in the shortest possible time. It is also clearly shown in the cross-sectional view that the width of the remaining (longer) parallel wall 22 between the outwardly projecting edges 28 is approximately equal to the width B1 of the opposing (shorter) parallel wall 22 .

Figure 5 is a schematic diagram showing the changing deformation shift of the cage jacket due to dynamic vibration stress. The hydrostatic internal pressure of the fluid load - indicated on the right-hand side in Fig. 5 - produces the maximum cage deflection D _a , D _i at about the height of the center of gravity S of the load, i.e. about 33% of the cage height, and at this height the outward The amplitude of the vibration is about twice that of the inward vibration, which is why cracks in the cage tubes form during vibration stress in the region of the lower half of the cage, which is the most dangerous.

The schematic diagram of the partial sectional view in Fig. 6 shows a horizontal cross-section at the location of the maximum deformation effects D _a and D _i . The outwardly directed vibration deflects without interference, while the inwardly directed liquid column encounters the opposite side wall. Consequently, the lower circumferential horizontal cage bars 30 are subjected to high bending stresses especially at the corner turns 38 .

Figure 7 - in view from inside the cage - shows the intersection 36 of the horizontal pipe rod 30 with the vertical pipe rod 32 . Four solder joints are indicated at intersections 36 . The trapezoidal tube profiles of the horizontal bar 30 and the vertical bar 32 are provided with a notch 34 on each side near the intersection point 36 respectively, forming four welding points respectively, whereby the notch 34 is separated from the intersection point 36 by at least the tube. One tenth of the rod width B. The undeformed trapezoidal profile 18 along viewing direction D is shown in FIG. 8 , and the view of the indentation 34 along line C-C is shown in FIG. 9 . The dimples 34 in the stem may be formed on the ("longer") parallel wall 22 side or/and on the opposite ("shorter") parallel wall 20 side. Thus, various variants can be realized such that at the intersection of two cage bars at least two indentations can be provided on the outside of the trapezoidal profile or/and two indentations can also be provided on the inside. However, the most important thing for these embodiments is that the pipe rods are not dented or deformed directly at the intersection points or respectively at the welding points, but only at a certain distance from these places. When reducing the profile height H, the depth T of one indentation 34 should be kept low if possible, i.e. in the range of 15% to 50%; in a preferred embodiment the indentation depth T is about the profile height H 33%. The longitudinal extension of the dimples 34 along the bar should be in the range of about one and a half to three times the profile width B, in a preferred embodiment the longitudinal extension of the dimples 34 is about twice the profile width B.

Figure 10 shows an unstressed known type of pipe profile with a square profile along the entire length of the pipe. As shown in FIG. 11 , after being subjected to dynamic vibration stress for a short period of time, cracks can be seen forming on the horizontal bars 30' at the intersection points, and these cracks are respectively located at the solder joints.

The formation of cracks or tearing of the cage rods always occurs in the area of the greatest tension, or where the cage jacket bulges the most. The vertical pipe rods are arranged on the inside of the cage-shaped jacket, and the horizontal pipe rods are arranged on the outside. Cracks and fractures always occur in the intersection area closest to the solder joint (refer to the circled illustration in Figure 2). Cracks initiated on vertical pipe rods - relative to the jacket - always propagate from the outside to the inside, and always from the inside to the outside of the horizontal rods. It has been found in comparative tests that cage jackets made of cage rods with open profiles and straight outward bevels exhibit good stackability due to the distance between the welds at the intersections, but They are however the most unfavorable to vibration stress.

In FIG. 12 , the closed trapezoidal tube profile 18 according to the invention has two indentations 34 on the horizontal bar 30 compared to the square tube profile. As shown in an exaggerated manner in FIG. 13 , no cracks were formed even after long-term exposure to vibrational stress. On the one hand, this is due to the fact that the solder joints in the intersection area are very stable without indentations leading to weak points, and on the other hand, the indentations 34 reduce the section modulus and act as a sort of "bending hinge" at at least a small distance from the intersection point. ", thereby preventing the peak tension from acting on the sensitive solder joint and shifting the peak tension to the farther elastic area.

A particular problem in constructing a particular embodiment of the cage housing is that the vertical and horizontal cage bars should be as stable and rigid as possible to prevent eg excessive bulging of the pallet container under internal pressure; on the other hand, a high flexural section modulus should be provided to counteract the constant dynamic vibration stress, thus the above two criteria are in opposition to each other. When considering favorable circumstances, such as low production costs, an optimal solution must be found. According to a recent trend of the invention, pallet containers are known with cage rods that are profiled flat along the rod length, as for example according to DE 297 19 830 U1, which may be suitable as storage containers, but not as transport under dynamic vibration stress Containers for hazardous fluid contents.

The patent documents cited above are based on the prior art known pallet containers with cage-shaped jackets made of circular cross-section tubes provided with indentations at least at welded tube intersections. The description on page 2 of the patent publication states that "By using a profiled tube according to the invention (without any local dimples) (there) localized tension buildup is avoided...", but it does not correctly state the The recent trend, and only showing that the inverse relationship between flexural strength and vibration elasticity has not been considered when the cage jacket of such palletized containers is subjected to transport stresses.

According to the present invention, the depth T of the trapezoidal profile indentation 34 is between about 25% and 50% of the profile height H of the stem, preferably about 33%. An indentation of 5 mm is generally sufficient for a tube with a height of 15 mm, whereby the vibration stresses of the solder joints are kept low or eliminated while maintaining a sufficiently high rigidity in the tube. This stiffness is important to keep the lateral protrusion amplitude of the vibrating cage low.

Figure 14 shows an embodiment with two indentations 34 on the side of the pipe profile facing away from the weld spot of the short parallel wall 20, and - as shown in Figure 15 - it shows a modification of this embodiment and particularly useful variants. The trapezoidal tubular profile 18 is provided with indentations 34 located exactly opposite each other on the side of the shorter parallel wall 20 and the side of the longer parallel wall 22 transversely close to the point of intersection 36 . The distance between the indentation and the point of intersection 36 here is approximately one-tenth of the width B of the profile of the tube rod. The arrangement of the indentations on each of the parallel extending side walls 20, 22 in particular enhances the "hinge action" or elasticity of the tube profile.

According to the teachings of the present invention, the configuration of the indentations 34 in the horizontal and vertical pipe rods 30, 32 can be of different depths depending on the expected dynamic stress levels on the cage jacket 14. Therefore, according to special requirements or needs, while maintaining sufficient bending strength, it is possible to control the level and Optimum vibration elasticity in vertical pipe rods.

Figure 16 shows another important embodiment for reducing the undesirable effects of dynamic vibration stresses of horizontal pipe rods. In the area of the 90° corners and parallel to the vertical, the horizontal tubes 30 of the cage jacket 14 flatten so that they also act as "bend joints" in the form of hinges. In the corner area, the horizontal pipe does not need to have a high bending capacity, what is more important here is a high elasticity. Particularly favorable test results have been achieved with a pallet container in which the horizontal pipe rods 30 of the pallet container are flattened by at least four quarters of the diameter H of the profile 18 from the inside and/or from the outside in the corner region 38 of the support jacket 14. one-third. In one embodiment of the actual construction, the horizontal tubes in the lower part of the cage are flattened by about 20% from the inside and about 35% from the outer corner arcs, while the flattening of the upper area of the cage is gradually reduced of.

It should be pointed out here that the essential features of the present invention are schematically and exaggeratedly shown in the drawings, which should not be construed as limiting, but merely for illustration purposes and to facilitate a better understanding of the observer.

It should be understood that the variations shown can be combined in various ways and that other combinations are also included within the spirit of the invention. The above mentioned possible variants, in particular the lower part of the cage jacket can be provided with different means to achieve sufficient bending strength with optimally adapted pipe rod elasticity.

List of Reference Numbers

10 pallet containers

12 inner container HD-PE

14 cage coat

16 base plate

18 trapezoidal profile

20 short parallel sides

22 long parallel sides

24 Straight inclined walls

26 top angle

28 convex (raised)

30 horizontal bars

32 vertical rod

34 Dents (30, 32)

36 Cross (30, 32)

38 Corner Arc(30)

40 flattened(38)

A distance (22-22)

B width profile tube

B1 Reduced Width(22)

H height profile tube

S Gravity loading point

T Depth Dent(34)

Da external deformation

Di internal deformation

Claims (15)

1. Pallet container (10), which has a thin-walled rigid inner container (12) made of thermoplastics for storage and transportation of fluid or free-flowing goods, and the inner container is covered by an outer cage-shaped jacket ( 14) and the base supporting plate (16) are closely surrounded, and the thermoplastic container is supported on the base supporting plate and the base supporting plate is firmly connected on the supporting shell; wherein the cage-shaped overcoat (14) is welded on the composed of vertical and horizontal hollow rods (30, 32) together, It is characterized in that, The hollow rods (30, 32) have a closed trapezoidal cross-sectional profile (18) with longer and shorter walls extending parallel to each other and two straight walls (24) extending at an oblique angle to each other, These two straight walls extend from the longer parallel wall (22) and connect to the shorter wall, whereby the two beveled straight side walls of the hollow bar profile (18) are formed between 20° and 45° The top angle within the range; wherein the trapezoidal hollow rod profile (18) is provided with a dent (34) on each side of the solder joint near the solder joint, and the distance between the dent and the solder joint is 2 one tenth. 2. A pallet container as claimed in claim 1, It is characterized in that, The height/width ratio (H/B) of the trapezoidal hollow rod profile (18) is in the range of 0.8 to 1.0. 3. A pallet container as claimed in claim 1 or 2, It is characterized in that, The longer parallel walls (22) of the trapezoidal hollow rod profile (18) are recessed inwardly at the intersection region (36) of the two hollow rods (30, 32) in such a way that a Convexity (28) such that at each intersection (36) of horizontally and vertically extending hollow rods (30, 32) four contact points are formed which are firmly interconnected after welding, wherein at each hollow rod The mutually facing longer walls of the intersection (36) are still spaced apart from each other after welding and do not touch each other. 4. A pallet container as claimed in claim 1 or 2, It is characterized in that, The longer parallel walls (22) of the trapezoidal profile (18) are recessed inwardly along the entire length of the tube so that a convex surface (28) is formed on each of the two outer longitudinal edges and extends the hollow rod horizontally and vertically Each intersection (36) of (30, 32) forms four contact points, which are firmly connected to each other after welding, wherein the longer parallel walls (22) facing each other at each intersection of the hollow rods After welding, they are still separated by a certain distance and do not touch each other. 5. A pallet container as claimed in claim 1 or 2, It is characterized in that, The longer parallel walls (22) of the trapezoidal profile (18) of one hollow rod are inwardly recessed in the intersection region, and in the other hollow rod (32, 30) the longer parallel walls (22) of the trapezoidal profile (18) ) is inwardly recessed along the entire length of the hollow rod. 6. The pallet container according to claim 1 or 2, It is characterized in that, The distance (A) between the two longer parallel walls (22) of the intersecting hollow rods (30, 32) after welding is between 0.5 mm and 2 mm. 7. The pallet container according to claim 1 or 2, It is characterized in that, The remaining longer parallel walls (22) between the outwardly extending convex surfaces (28) have the same width (B1 ). 8. The pallet container according to claim 1 or 2, It is characterized in that, The trapezoidal hollow profile (18) has at least one indentation (34) on the side of the longer parallel wall (22), the indentation being at a distance from the soldering point and laterally abutting the soldering point. 9. A pallet container according to claim 1 or 2, It is characterized in that, Provide at least two indentations (34) between the two intersections (36) on the shorter parallel wall (20), i.e. on the opposite side of the solder joint, or/and on the side of the longer parallel wall (22) , ie at least two indentations (34) are provided on the side of the solder joint. 10. A pallet container according to claim 1 or 2, It is characterized in that, The depth (T) of the indentation (34) reducing the profile height (H) is kept relatively small, ie between 15% and 50% of the profile height (H). 11. A pallet container according to claim 1 or 2, It is characterized in that, The longitudinal extension of the indentation ( 34 )—in the longitudinal direction of the hollow rod—is between 1.5 and 3 times the profile width (B). 12. A pallet container according to claim 1 or 2, It is characterized in that, On the side of the shorter parallel wall (20) and on the side of the longer parallel wall (22), each trapezoidal hollow bar profile (18) is provided with indentations (34) respectively laterally adjacent to the intersection (36), so that The dimples ( 34 ) are exactly opposite each other, wherein the distance between the dimples ( 34 ) and the intersection ( 36 ) is one-tenth of the width (B) of the profile of the hollow rod. 13. A pallet container according to claim 1 or 2, It is characterized in that, Depending on the intensity of the dynamic vibration stresses, the indentations of the pipe rods (30, 32) have different depths in various regions of the cage casing (14) or/and in the horizontal and vertical hollow rods (30, 32). 14. A pallet container according to claim 1 or 2, It is characterized in that, In the corner area ( 38 ) where the angle becomes 90°, the horizontal hollow rods ( 30 ) are respectively flattened in parallel in the vertical direction. 15. The pallet container according to claim 14, characterized in that, in the corner area (38) bent into a 90° angle, the hollow rod (30) has at least a profile flattened from the inside or/and from the outside (18) A configuration that is one quarter of the cross-sectional height (H).

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