EP2340217B1 - Pallet container - Google Patents

Description

The invention relates to a pallet container with a thin-walled rigid inner container made of thermoplastic material for the storage and transport of liquid or flowable products, with a plastic container as a support frame tightly enclosing Gitterrohrstützmantel and with a bottom pallet on which the plastic container rests and with which the support shell fixed connected is. The lattice support shell (outer container) of the pallet container consists of welded vertical and horizontal tubes. In order to obtain a closed outer container, the circulating horizontal tubes are each firmly connected to each other at at least one point.

State of the art:

Such pallet containers with welded lattice tube support jacket are well known, such. B. from the EP 0 734 967 A , The lattice tube support casing of the pallet container known therefrom consists of a round tube profile which is strongly compressed at the welded intersection points. From the DE 297 19 830 U1 Another pallet container is known, the bars have a deviating from the circular cross-section tube profile, however, should expressly have a consistent over the entire length cross-section without any dents or querschnittsvermindernde indentations. Another pallet container with a Gitterrohrstützmantel of open profile bars is from the DE 196 42 242 A known. Furthermore, various pallet containers with square grid bar tube cross-section belong to the known prior art.

A special version of a tubular support shell is in the EP 1 939 108 A1 (OMC). The pallet container known therefrom has a square lattice rod tube cross section at its vertical tube rods and a circular lattice rod tube cross section at its horizontal tube rods and on. In the connection of the rotating horizontal round tubes, the one pipe end is tapered and inserted into the other in cross-section unaltered pipe end. To prevent slipping apart of the pipe ends are several, preferably eight connecting means such. B. welds or screws provided, which penetrate the walls of both round tubes.

The attachment of the lattice tube support mantle on the bottom pallet, this can be designed as a flat pallet made of plastic, wood, steel or parts thereof with steel tube frame (composite pallet) is usually carried out by means of or through the lower horizontal encircling grid frame tube cross fasteners such. B. Screws, clips, braces or claws. The fasteners are nailed, pinned, bolted or welded onto the top plate or the top outer edge of the pallet. For steel pallets, the tubular space frame is directly welded on. For industrial use or when using pallet containers in the chemical industry, they must undergo official approval sampling and fulfill various quality criteria. For example, internal pressure tests as well as drop tests with filled pallet containers are carried out from certain drop heights. Pallet containers or combination IBCs (IBC = intermediate bulk container) of the type mentioned here - in a lightweight construction without massive corner support posts with a curb weight of about 60 to 80 kg depending on the type of pallet for one 1000 liter IBCs - are preferably used for the transport of liquids. In particular, in the truck transport of filled combination IBCs caused by the transport shocks and movements of the transport vehicle - in particular on bad roads - significant surge of liquid product, which constantly changing pressure forces are exerted on the walls of the inner container, which in turn for rectangular pallet containers too radial vibration movements of the grid tube support jacket lead (dynamic continuous vibration load). Depending on the design of the grid tube support jacket, the loads are so high during longer transport on bad roads that welds in the crossing areas and even individual bars of the pipe grid can tire and break.

The peripheral pipe connections of the horizontal tubes of the tubular supporting jacket provide a special place, especially when transport loads and approval tests (vibration test for 1 hour with subsequent internal pressure test of 100 kPa for 10 minutes), at the preferred fatigue cracks or pipe breaks can occur. The horizontal and vertical tube rods of the most common combination IBCs today have a circular or square tube cross-section.

In the case of the horizontal pipe connections, one side of the pipe is reduced in size and inserted into the other open end of the pipe by approx. 50 mm, after which the joint is reworked in various ways. In the known pallet containers with a circular cross-section of the bars ( US 5,678,688 ) This post-processing is done horizontally from the inside; the tube connection is pressed in radially from the inside in such a way that the rear half of the tube turns flush against the inside of the front tube half. and from the outside then retaining tongues / holes are punched in quadruple wall of this pipe connection.

In another known pallet container with square tube cross-section ( US 5,645,185 ), the outer pipe end is provided after insertion of the inner pipe end with a plurality of pressed in the angular corner regions of the pipe cross-section peripheral notches. In addition, fixing screws are still used for the most heavily loaded pipe connections for reinforcement.

In another known pallet container with square tube cross-section ( US 6,244,453 ), the outer half of the pipe joint is compressed over a certain length in the vertical direction and wavy against each other verclincht. The inner half of the pipe connection remains undeformed. To counteract tensile stresses z. B. to be in the internal pressure test, but the interlocking Verclinchung must be performed comparatively deep or sharp, so that at this external location under normal load the risk may consist of material overstress. All known pipe connections are usually arranged centrally in a line one above the other in the grid wall of the lattice support shell, in which the centrally arranged in the bottom region of the plastic inner container removal fitting for the liquid product is.

Task:

It is an object of the present invention to avoid the disadvantages of the prior art and an improved pipe joint without additional fasteners such. For example, it is necessary to specify screws which have a higher resistance, in particular to dynamic vibration loads (eg vibration test with subsequent internal pressure test) and longer-lasting vibration stresses with simultaneous stacking load (eg transport loads).

Solution:

This object is achieved in that the connection of the horizontal tubes is effected by a arranged on the inner side of the horizontal tubes positive Verclinchung, wherein the outer side of the horizontal tubes are free of any deformations. The Verclinchung is executed only on the inner half of the horizontal tubes by a vertical injection of the top and bottom by means of appropriate ram as undulating interlocking positive connection. The inventive inner side arrangement of the positive Verclinchung the horizontal tubes in their connection area so only the inner half of the tube ends is deformed and the outer half of the horizontal tubes with square tube cross-section remains free of any indentations. Since any cold deformation such. B. a Verclinchung causes an increase in strength of the material structure, it also means a reduction of the previous elasticity at the same time. The positive material accumulation and mutual support of Rohrober- and - bottom (double tube) also represents a pipe stiffener.

In the vibration test, the side walls of the lattice frame oscillate alternately elastically inwards and outwards from the normal flat position by the movement of the liquid filling material. The elastic deformation of the side walls is greatest in the central region, the "bulge" outwards being about twice as large as the "denting" inwards. As a result, approximately twice as high tensile stresses occur on deformation on the outer side of the horizontal bars as on deformation on the inner side of the horizontal bars. Tensile stresses are extremely critical in contrast to compressive stresses, especially in dynamic pressure cycling loads and can be damaging to material from a certain height. They cause cracking mostly at transition points of pipe cross-sectional changes. The inventive embodiment of the pipe joint is now advantageously the undeformed outer half of the horizontal tubes in the region of greater deflection (outward) with higher tensile stresses and the inner half of the horizontal bars with positive Verclinchung (and higher rigidity with less elasticity) is in the field of lower pipe bar deflection (inwards) with the lower tensile stresses there.

As a result, a viable connection is created in which no additional tools such as screws are needed, which has a much higher resilience and resistance to bending cycles and especially against long-lasting dynamic vibration loads.

• In einer abgewandelten Ausführung der Erfindung kann die Anordnung der Rohrverbindung mit Verclinchung der horizontalen Rohre des Gitterrohrstützmantels bei gleicher Umfangsposition mit wechselweise unterschiedlichen Einschubrichtungen ausgeführt sein. Dabei wird bei einem Horizontalstab einmal das rechtsseitige Rohrende verkleinert und in das linksseitige Rohrende eingesteckt und zum anderen bei dem nächsten Horizontalstab das linksseitige Rohrende verkleinert und in das rechtsseitige Rohrende eingesteckt usw. Auf diese Weise wird eine Vergleichmäßigung des Verbindungsbereiches bewirkt, wobei keine Einsteckrichtung bevorzugt ist.
• In einer anderen Ausführung der Erfindung kann die Rohrverbindung der horizontalen Gitterrohre außermittig linienförmig übereinander in einer Seitenwandung des Gitterrohrstützmantels angeordnet sein. Da in der Mitte der Gitterwandungen die größte Deformation auftritt, wird durch diese vorteilhafte Maßnahme eine Verlagerung der Rohrverclinchungen in Bereiche mit niedrigeren Spitzenspannungen bewirkt.
• In einer weiteren Ausführung der Erfindung kann die Rohrverbindung der horizontalen Gitterrohre außermittig wechselweise übereinanderliegend in einer Seitenwandung des Gitterrohrstützmantels angeordnet sein. Da die Verclinchung der Horizontalrohre im Verbindungsbereich immer auch eine Versteifung an dieser Stelle verursacht, wird durch diese Ausführungsvariante eine Vergleichmäßigung des Elastizitätsverhaltens der gesamten Seitenwandung mit Verbindungsbereich im Vergleich zu den anderen Seitenwandungen des Gitterrahmens ohne Verbindungsbereiche der Horizontalstäbe erzielt.

Further embodiments of the invention are as follows:

• In a modified embodiment of the invention, the arrangement of the pipe connection with Verclinchung the horizontal tubes of the lattice support tube can be performed at the same circumferential position with alternately different insertion directions. In this case, the right-hand tube end is once reduced in size and plugged into the left-hand tube end and on the other hand reduced the left side tube end in the next horizontal bar and inserted into the right-side tube end, etc. In this way, a homogenization of the connection area is effected, with no insertion is preferred ,
• In another embodiment of the invention, the pipe connection of the horizontal grid pipes may be arranged off-center in line form one above the other in a side wall of the grid pipe support jacket. Since the greatest deformation occurs in the middle of the lattice walls, this advantageous measure causes a displacement of the pipe connections into areas with lower peak voltages.
• In a further embodiment of the invention, the pipe connection of the horizontal grid pipes may be arranged eccentrically alternately one above the other in a side wall of the grid pipe support jacket. Since the Verclinchung the horizontal tubes in the connection area always causes a stiffening at this point, an equalization of the elasticity behavior of the entire side wall with connection area compared to the other side walls of the grid frame is achieved without connecting portions of the horizontal bars by this embodiment variant.

Advantages:

• the arrangement of the tube connections of the horizontal tubes of the grid tube support jacket inwardly towards the inner container causes improved resistance to long-term bending cycles;
• the arrangement of the tube connections of the horizontal tubes inwards toward the inner container is optically more advantageous, because the wave-shaped concavity is not seen when looking from the outside or does not look directly at it;
• a tearing of the horizontal tubes in the clinch connections as a notch vulnerability from the outside is prevented because the pipe connections are now in the inside of the tolerable tensile stresses of bending stress, which usually arise during long transports or vibration tests.

In an embodiment of the invention, it is provided that the clinch connections are no longer arranged in the central region of a side wall (= the region of greatest deflection), but in an off-center region of the side wall. Laying the pipe connections in off-center areas of the side walls of the lattice pipe support jacket has the great advantage that there occur only lower deflections of the side walls with lower peak values of tension / pressure alternating loads.

The outer and outer cross-sectional areas of the horizontal bars (with the highest tensile load) are advantageously not deformed in the outer tubes (which are pushed in the connection area on the other end of the tube inserted) by the clinching, the inner tube is deformed outwardly only in the longitudinal direction, so that the inner tube portions (with the clinch deformation) are mainly claimed by harmless compressive stresses.

Figur 1

einen erfindungsgemäßen Palettencontainer,

Figur 2

in Teilansicht die auftretende elastische Deformation des Gitterrohrstützmantels bei Transportbelastungen,

Figur 3

die Deformation des Gitterrohrstützmantel in Draufsicht auf die Gitterwand,

Figur 4

den Clinchbereich eines horizontalen Rohres von der Innenseite her,

Figur 5

den Clinchbereich eines horizontalen Rohres von der Außenseite her,

Figur 6

den Clinchbereich eines horizontalen Rohres mit Innenbehälter im statischen Ruhezustand von oben her betrachtet,

Figur 7

den Clinchbereich eines horizontalen Rohres mit Innenbehälter im Zustand einer Deformation nach außen ebenfalls von oben her betrachtet,

Figur 8

Schnitt durch den Verbindungsbereich (Verclinchung) gem. Fig. 7,

Figur 9

eine andere Ausführungsvariante des erfindungsgemäßen Palettencontainers mit Clinchbereichen in unterschiedlicher Anordnungsrichtung,

Figur 10

das Prinzip einer Rissfortbildung bei Innendruckprüfung mit Verclinchung in gleicher Umfangsposition,

Figur 11

eine weitere Ausführungsvariante des erfindungsgemäßen Palettencontainers mit Clinchbereichen in unterschiedlicher Anordnungspositionierung,

Figur 12

das Prinzip einer Rissabstützung bei einem Gitterrohrstützmantel mit Clinchbereichen in unterschiedlichen Umfangspositionen und

Figur 13

eine weitere Ausführungsvariante des Palettencontainers mit Clinchbereichen an Stellen geringerer Biegewechselspannungen.

The invention will be explained and described in more detail with reference to the embodiments schematically illustrated in the drawings. Show it :

FIG. 1

a pallet container according to the invention,

FIG. 2

in partial view, the occurring elastic deformation of the grid tube support jacket during transport loads,

FIG. 3

the deformation of the grid tube supporting jacket in plan view of the grid wall,

FIG. 4

the clinch area of a horizontal tube from the inside,

FIG. 5

the clinching area of a horizontal pipe from the outside,

FIG. 6

the clinch area of a horizontal tube with inner container in the static rest state seen from above,

FIG. 7

the clinch area of a horizontal tube with inner container in a state of deformation outwards also viewed from above,

FIG. 8

Section through the connection area (clinching) acc. Fig. 7 .

FIG. 9

another embodiment variant of the pallet container according to the invention with clinch areas in a different arrangement direction,

FIG. 10

the principle of crack propagation in internal pressure testing with clinching in the same circumferential position,

FIG. 11

a further embodiment of the pallet container according to the invention with clinch areas in different arrangement positioning,

FIG. 12

the principle of a crack support in a Gitterrohrstützmantel with clinch areas in different circumferential positions and

FIG. 13

a further embodiment of the pallet container with clinch areas at places lower bending stress.

In FIG. 1 is designated by the reference numeral 10, an inventive pallet container, with a thin-walled rigid inner container 12 made of thermoplastic material for the storage and transport of particular dangerous liquid products, with a plastic container 12 as a support frame tightly enclosing lattice support jacket 14 and a bottom pallet 16, on which the plastic container 12 rests and with which the support jacket 14 is firmly connected. The lattice tube support jacket 14 (outer container) of the pallet container 10 consists of vertical and horizontal tubes 18, 20 welded together. In order to obtain a closed outer container, the circulating horizontal tubes 18 are connected to each other. Here is the connection region of the horizontal tubes 18 - as usual in the past - centrally in one of the two shorter side walls of the pallet container 10 just above the center in the bottom portion of the inner container 12 connected extraction fitting 22. In the present case is drawn by the in the horizontal tubes 18, left pointing arrowheads indicated that the right side pipe end formed reduced in size and is plugged into the unchanged left-side pipe end. The Verclinchung the horizontal tubes is designed inside and thus not visible from the outside.

In order to reduce the size of a pipe end in cross-section and plug in the other end of the tube, the previously undeformed, each paired mutually parallel side walls of the square tube cross-section over a length of about 50 mm are so pressed inward at the einzusteckenden pipe end to a close X-shaped tube cross-section is formed, the corner edges are also drawn something inside, so that they can be inserted into the undeformed square tube cross-section of the other pipe end.

To explain the elastic deflection behavior of the side walls of a pallet container 10 in transport loads is in FIG. 2 schematically shown that the maximum deflection of the lattice tube walls at the location of the center of mass "S" of a filled pallet container occurs and is about 33% of the height - measured from the pallet 16 - the side wall is located, wherein the deflection "Da" outwards is about twice as large as the deflection "Di" inward. In addition the plan view in FIG. 3 in that the maximum deflection lies in each case in the middle of a side wall.

FIG. 4 shows in a plan view of the inside of a horizontal tube 18, the connection area according to the invention, the inner Verclinchung the horizontal tube 18. In this case, three teeth of the clinching tool vertically from above and four offset thereto arranged picking teeth were vertically formed from below into the inner half of the horizontal tube 18 such that a solid undetachable, wavy positive connection of both pipe ends 26, 28 is formed.

According to shows FIG. 5 the same connection region of the horizontal tube 18 Fig. 4 , It can be clearly seen that the outside of the outer tube end 26 has no clinching deformations and is thus free of any dents.

In FIG. 6 is shown in partial cross-sectional top view of the connecting portion of a horizontal tube 18 with internally fitting plastic container 12 in the static rest state. Here, the side wall of the pallet container as good as no deflection. On the other hand shows FIG. 7 the same connection area in the state of a surge load by the back and forth sloshing liquid product with corresponding deflection of the side wall to the outside. According to section line VIII-VIII is in FIG. 8 a cross-sectional view of the clinched connection region 24 shown. On the left side it becomes clear how the two pipe ends 26, 28 are positively interlocked with each other. In this case, the outer wall of the outer tube end 26 on the right side of the representation is completely free of indentations. It is precisely this undeformed outer wall, which still has its original higher elasticity (in contrast to the reduced-elasticity clinching areas stiffened by cold-working), without prejudice to the highest values of critical tensile stresses. The inventive type of wavy positive connection only on the inside of the horizontal tubes is in contrast to other pipe connections (with screws and screw holes or stamped hook eyes) an optimal solution, because only material folds are introduced, but no tearing or breaking of the material structure, because that is usually the germ cells for cracking.

In FIG. 9 a variant is shown, in which the two pipe ends 26, 28 of the horizontal grid pipes are alternately plugged into each other and clinched. Once the left end of the tube is reduced (= arrowhead) and inserted into the right undeformed tube end, the next horizontal tube, the pipe joint is formed correspondingly reversed.

FIG. 10 Figure 1 illustrates cracking of a critical pipe joint and subsequent tearing of further adjacent connections. Usually, cracking starts at the point of highest stress. This is usually done in the middle region of the second-lowest horizontal bar No. 3 between the vertical bars B and C. Is there the Verclinchung torn in the bar 3 or completely broken, there is an additional burden on the bars B and C on the Lines of the horizontal bars 4 and 2, which are then torn by the additional burden due to the failure of the torn pipe connection in their connection area.

In FIG. 11 another advantageous arrangement of the connections according to the present invention is shown on different circumferential positions. In this case, the pipe connections are each arranged alternately off-center in the grid wall once to the right and once offset to the left side. In such a variant, however, no tensile forces are transmitted by torn Verclinchungen to other adjacent Verclinchungen and must not be included by those.

This is for this variant in FIG. 12 has been shown schematically that a pipe break - even if he would occur here - is relatively uncritical, because by the failure of a broken pipe joint, the other adjacent pipe joints are not additionally burdened and thus overloaded. This is because in this case each pipe connection is surrounded by around six firmly welded intersection points of vertical and horizontal bars and in a grid field (grid rectangle), in which the adjacent horizontal tubes have no pipe connection. In contrast, the pipe joints of the adjacent horizontal bars are always arranged in a grid field located further away, and bending stresses of a broken pipe connection can not be transferred directly to and load the next pipe connection.

Finally shows FIG. 13 Yet another embodiment in which the pipe connections 24 are indeed arranged one above the other but off-center in the front side wall of the pallet container 10. In this case, the pipe connections 24 can be provided on the right-hand or left-hand side of the middle of the side wall (just above the removal fitting 22). There they are in a region of lesser deflection and are therefore no longer subject to the high critical tensile stresses. Overall, therefore, taught by the present invention, a doctrine as the resistance of a lattice frame for a pallet container with welded horizontal and vertical tubes with square pipe cross-section against dynamic duration vibration load can be improved or increased in a simple manner.

References list

10

pallet container

12

Plastic containers

14

lattice frame

16

bottom pallet

18

horizontal grid pipe (14)

20

vertical grid pipe (14)

22

Removal fitting (12)

24

Connection area occlusion (18)

26

outside pipe end (24)

28

inside pipe end (24)

Claims (5)

1. Pallet container (10) having a thin-walled rigid inner receptacle (12) made of thermoplastic material for storing and transporting liquid or flowable charges, having a support casing (14) in the form of a tubular grid, which closely surrounds the plastics receptacle (12), and having a base pallet (16) on which the plastics receptacle (12) rests and to which the support casing (14) is fixedly connected, wherein the tubular-grid support casing (14) is made of vertical and horizontal tubes (18, 20) which are welded together and the peripheral horizontal tubes (18) are each fixedly connected to one another, wherein the one tube end is made smaller and is inserted into the unchanged other tube end,
   characterised in that
   the horizontal tubes (18) are connected by form-fitting clinching (24) on the inner side of the horizontal tubes (18), wherein the outer side of the horizontal tubes (18) is free of any clinching deformation.
2. Pallet container according to Claim 1,
   characterised in that
   the tube connections with clinching (24) of the horizontal tubes (18) of the tubular-grid support casing (14) have the same peripheral position and alternately different directions of insertion.
3. Pallet container according to Claim 1 or 2,
   characterised in that
   the tube connections (24) of the horizontal grid tubes (18) are arranged eccentrically, in a line one above the other in a side wall of the tubular-grid support casing (14).
4. Pallet container according to Claim 1, 2 or 3,
   characterised in that
   the tube connections (24) of the horizontal grid tubes (18) are arranged eccentrically and alternately one above the other in a side wall of the tubular-grid support casing (14).
5. Pallet container according to Claim 1,
   characterised in that
   the depth of the clinching, which is determined by the depth of penetration of the biting teeth of the clinching tool, increases towards the centre of the tube connection (24) and decreases in each case laterally outwards.

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