DE7515851U - Plastic containers - Google Patents

Description

Patent attorneys /

Dipl.-Ing. Helmut Missling 6300 Giessen 7.4.1977 h \

Dipl.-Ing. Richard Schlee Bismarckstrasse 43

_{n ,,, Λ} ... .. Telephone: (0641) 71019

Dipl.-Ing. Arne Missling

S / B 12.523

Ref .: Utility model auxiliary registration G 75 15 851.9

Machine and tool construction GmbH. 3561 Dautphetal-Wolfgruben / Biedenkopf district

Plastic containers

The invention relates to a container made of plastic, in particular a storage container for liquids, e.g. Heating oil that is produced in a blow molding process and has stiffening ribs created by beads in the container wall are formed.

In the case of containers of the type mentioned at the outset, there is a general problem of giving the container the necessary rigidity especially for large containers such as those used to store liquids such as heating oil. Various constructions are known that have the necessary

Have rigidity. Mostly used is the bandaging of the container, whereby the loading |

I container wall rigid steel profiles are inserted, the

usually extend along the side walls of the container

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and are connected to one another by front band parts. Bandages, several of which are usually needed for one tank are expensive and make up a significant proportion of the total manufacturing cost. The surrounds for the recording the bandages for their part have a certain stiffening effect even without inserted profiles, but this stiffening effect is sufficient It is far from clear why bandages are indispensable. The poor stiffening effect of the beads is due to the fact that the internal pressure in the container, e.g. the static pressure of a stored liquid, causes the beads to expand tried, whereby their flexural strength is very much reduced.

A container is also known (DT-GbmS 7 112 258), in which opposing walls have deep indentations, which touch in the middle plane of the container and are welded to one another there. This gives you an essential one Increase in pressure resistance, but this is paid for with a strong reduction in container capacity, i.e. at Given the external dimensions, the holding force of the container is smaller than that of containers without indentations. With the prescribed container capacity Therefore, larger dimensions of a storage room or the like may be required. A disadvantage Such a container also consists in the fact that the weld point at which the indentations are welded together,

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is exposed to the stored goods. This can happen with certain media, such as heating oil, lead to a swelling of the plastic material at the welding point, especially if at the edge a stress crack has occurred at the weld. As a result, the entire welded joint can over time are destroyed, after which the container no longer has the required compressive strength.

The invention is based on the object of designing a container of the type mentioned at the outset in such a way that bandages are used as stiffening means can be avoided and the stiffening means do not affect the capacity of the container.

The container according to the invention of the type mentioned is characterized in that opposing walls the corrugations either with one another or with an inserted into the corrugation, but not reaching through the container wall Profile are welded.

By the inventive fixation of the bead walls, either by direct welding or by welding with an inserted profile, the internal pressure can expand the bead does not effect. The bead that is found in the

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can also be referred to as a stiffening rib according to the container,
because a channel-shaped recess in the form of a bead on the
finished container no longer has to be present, can now
have a very strong stiffening effect, so that bandaging of the container or other stiffening means are not required. This results in a lighter container compared to containers with bandages. A very important advantage is that the overall manufacturing costs are greatly reduced. Since, according to the invention, possibly inserted profiles do not reach through the container wall, there are also no sealing difficulties due to the stiffening means.

In a preferred embodiment, the stiffening ribs protrude into the interior of the container, although the scope of protection should also include those containers in which the stiffening ribs protrude outward. When protruding inward
Stiffening ribs are designed so that the one another
opposite bead walls are welded together up to the outer wall plane of the container, a completely smooth outside of the container is obtained. In the case of inwardly protruding stiffening ribs, the stored goods do not come into contact with the weld points, so that possible destruction by swelling or the like cannot occur.

The ribs are advantageously reinforced at their free edges. The reinforcement can consist of an edge bead,

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which has a substantially curved cross-section. However, other cross-sections can of course also be used for the reinforcement, for example when a profile with an approximately T-shaped cross-section is inserted.

The rib edge reinforcement can be filled with an inserted profile. Such an inserted profile results in a additional rigidity. However, in order to save material, embodiments are also provided in which the rib edge reinforcement is hollow. The inserted profile can be a round bar, preferably a tube. As inserted profiles Both plastic profiles and metal profiles as well as profiles made of other materials come into consideration, provided that it is the edge reinforcement of the ribs goes. When the opposite Bead walls are connected to one another indirectly via an inserted profile, this must naturally consist of one Consist of material that connects to the plastic of the container wall, so preferably made of plastic or from a with plastic coated material so that welding with the inserted profile is possible. Such a weld but is not necessary for the profile inserted into the edge reinforcement of the ribs.

According to a further embodiment of the invention, the inserted Profile have an approach that is between each other

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opposite walls of the Verelfungerippe reloht, the named walls are welded to the named approach and the approach optionally extends over the entire rib height or only over a part of the rib height, so that over a part the rib height, the opposing walls are welded directly to one another. Such an inserted profile can, if it is made of plastic, at the same time to form an edge reinforcement of the rib and for an indirect connection the bead walls serve one another. The inserted profile can have projections in the region of the attachment to which the container walls are adapted. This gives you one special intensive hold of an inserted profile, as a positive connection is established at the same time.

In an advantageous embodiment of the invention, the container has inwardly protruding projections which form pockets accessible from the outside and into which the stiffening ribs open, This embodiment has the advantage that inserted profiles with their ends opposite to those at right angles to the profiles running container walls are set back. In connection with a manufacturing process to be defined are the pockets are also an advantage. In the case of an angular container, for example a cuboid container, the pockets are advantageously arranged on the container edges, preferably such

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that the pockets are accessible from both surfaces adjoining the edges. The bags are in this case Particularly convenient to use as recessed grips, as they can be seen from both the front and the side walls of the Container are accessible, which makes handling a container, e.g. transporting it through a narrow doorway, essential relieved.

In the case of a container with essentially flat walls, the stiffening ribs can be arranged horizontally or vertically, horizontally, preferably when the largest wall dimension runs horizontally, vertically, preferably when the largest wall dimension runs vertically. The rib arrangement can, however, also according to the respective requirements. this Course differ. In the case of a round or oval container, the ribs can be arranged circumferentially and in one direction to the container axis right-angled plane. In this way, pressure-resistant containers are obtained to a particularly high degree. For example, a The tank to be buried in the ground must be designed in such a way as to obtain the necessary strength against the earth pressure. Even Containers to be loaded with internal pressure, e.g. compressed air containers, are advantageously designed with circumferential ribs. On the other hand, cylindrical and oval containers can also be provided with longitudinal ribs, which is useful when the container is subjected to bending stress, the internal pressure

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however, it is not excessively high. This would be the case, for example for a long storage container that is supported at a relatively large distance.

In a method for producing a container in which a plastic plastic tube is placed in a blow mold extruded, the blow mold is closed and the plastic tube is inflated, whereby it is attached to the wall of the blow mold creates, the opposing walls of the beads during the molding process with each other or with the Welded profiles.

This manufacturing process is particularly economical because there are no additional work steps for the connection are necessary and subsequent heating of the plastic is not necessary.

When producing a container with inwardly protruding stiffening ribs, according to a particularly advantageous Embodiment of the method in the blow mold by hand or automatically introduced profiles from the mold wall have a distance or rise from the mold wall. When the pressure is applied, the plastic hose snuggles to the profile. If the profile has a distance of

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the wall, it is encased by plastic and the plastic walls are pressed against each other on the other side of the profile and welded together. A profile that is only used for Formation of an edge reinforcement, e.g. a round rod, can now either be left in the container or off this can be pulled out.

The blow mold used for the process advantageously has Elevations for forming the inwardly protruding container projections, with holders, e.g. depressions, are arranged for holding the profiles. As already mentioned above, this avoids that the Ends of profiles that remain on the container protrude beyond the end walls of the container.

The blow mold can also be equipped with automatically extendable profiles. Here, the profiles can be lifted by means of hydraulic cylinders be actuated, which is preferably arranged on the side of the blow mold and cross members with the Profiles are connected. If such a mold is used, only containers are produced in which on finished tank insertion profiles do not remain.

In another method, the plastic tube is attached during and after the blowing process

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a retractable bar was created to form the bead has withdrawn this bar, and under the action of the inflation pressure, the opposing bead walls are pressed against each other and welded together. at To perfect this process, one side of the bar is cooled to cool one of the bead walls, so that this bead wall is cooled so far that it is already dimensionally stable, but can still be welded, after which the bar is withdrawn and the non-cooled bead wall is pressed against the cooled bead wall under the action of the inflation pressure and welded to it. By cooling down a wall, the bead is given a certain shape, which is defined by the cooled side surface of the bar.

In a method for producing a container with outwardly protruding stiffening ribs, in the blow mold In the still plastic state of the plastic, the opposing walls of the bead from the outside against each other pressed. This can be achieved using two different methods. In one method, the mold walls are relative In the case of the other method, the mold is subdivided. at

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Using sliding pressure bars, the mold is completely closed before blowing. If with shared Form is worked, a gap remains between the molded parts, into which the plastic tube is pushed by the internal pressure of the container is pushed in. The molded parts are then pushed together to press the bead walls together.

In another method of making one according to the invention The container is first made with a beaded container and after removing the container from the Blow mold the bead area is heated and the opposing side walls are inserted with one another or with one Welded profile.

Exemplary embodiments of the invention are shown in the drawing. Show it:

Fig. 1 is a perspective view of a container according to the invention, in which stiffening ribs are arranged in vertical planes,

2 shows a perspective view of a container according to the invention, in which the stiffening ribs are arranged in horizontal planes,

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Fig. 3 shows a vertical section through the container according to Fig. 2 according to the lines III-III in Figs. 2 and 4,

4 shows a horizontal section through the container according to FIG. 2 along the lines IV-IV in FIGS. 2 and 3 "

FIG. 5 in an enlarged illustration compared to FIG. 3 a cross section through a stiffening rib, FIG. 5 approximately a section corresponding to the dash-dotted circle V in Fig. 3 and wherein the stiffening rib is without an inserted profile,

FIG. 6 shows a representation corresponding to FIG. 5, wherein However, a tube is included in the stiffening rib,

Fig. 7 is a cross section of a rib in which the opposite Corrugated walls not directly, but indirectly with one another via an insert profile are connected,

8 shows a schematic representation of an open blow mold,

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9 shows an enlarged detail from FIG. 8 in the area of the dot-dash circle IX in FIG. 8,

FIG. 10 shows a partial section along line XX in FIG. 9 _t

11 one half of a blow mold with a mechanical one Extraction device for profiles,

Fig.12 shows a cross section through an essentially cylindrical container, the cutting plane being perpendicular to the longitudinal axis of the cylinder,

13 shows a section along line XIII-XIII in FIG. 12,

14 shows a longitudinal section through a cylindrical container with Ribs,

15 shows a cross section along the line XV-XV in FIG. 14,

Fig.i6 a cross section through a stiffening rib with inserted profile,

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Flg. 17 tells In view, tells In section a container with an outwardly protruding stiffening rib,

Flg. 18 shows a partial section through a blow mold for production of the container according to Flg. 17 during a first phase of work,

Flg. 19 a corresponding section in a further work phase,

20 shows a partial section through a further blow mold for

Production of a container with external stiffening ribs in an initial work phase,

21 shows a corresponding section in a further work phase,

22 shows a partial section through a blow mold according to a further embodiment of the invention in a first phase of work and

23 shows a corresponding section in a further work phase.

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The container according to FIG. 1 is essentially cuboid and has a bottom 1, end walls 2, 3, rare walls 4, 5 and one

j ceiling 6. In the ceiling 6 there are connecting pieces 7, 8, 9 for Arraa-

& doors arranged. Along the horizontal edges of the container

; _: are pockets 10 distributed inside the container

form protruding projections. The stiffening ribs 3ind

i; in this case arranged vertically and extending respectively

\. from the upper pocket 10 along the side wall 4 or 5 up to

an underlying pocket 10, what at the meeting of the container according to FIG. 2 will be explained in more detail.

^r In the case of the container according to Fig. 2, the vertical container

\ edges 11 pockets 10 arranged. The pockets extend

partly in the end walls 2 ¹ , 3 ¹ and partly in the side walls 4 ¹ , 5 ¹ . They can therefore be used comfortably as recessed grips, the container can be grasped from one end side as well as from a broad side without having to reach beyond the plane of the adjoining wall with gripping tools or hands, which means that the container is transported through made easier by narrow openings.

In the horizontal section according to FIG. 4, those in FIG

] areas appearing as pockets are visible as projections 10 '.

The stiffening ribs designated as a whole by 12 merge into the projections 10 ·. Have in the area between the pockets the ribs the cross-section shown in FIGS. 3 and 5,

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which is to be considered in more detail with reference to FIG. 5.

The rib 12 consists of two layers 13 and 14, which at 15 with each other are welded. The weld extends to the outer surface 16 of the container wall 5 '. At the crossing point there is no step between layers 13 and 14, i.e. surface 16 is perfectly smooth. The rib 12 has along her free edge a stiffening bead 18, which has an approximately circular cross-section and contains a cavity 19.

In the variant according to FIG. 6, there is a tube 20 in the cavity 19, on the outside 21 of which the plastic material is tight is snugly.

In the embodiment according to FIG. 7, the stiffening rib is designated as a whole by 22. The plastic layers 23 and 24 are here not directly welded to one another, but each separately welded to an inserted profile 25 made of plastic. The profile 25 has at one end a bead 26 with a circular cross-section, to which a long extension 27 connects. Projections 28, 29 protrude from the shoulder 27. The plastic layers 23 and 24 are snugly against the profile 25. An end face 30 of the profile attachment 27 is visible on the wall surface 29 of the container. This face is exactly in a plane with the rest of the wall surface 29 »so that too

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this wall surface is flat.

In Figs. Θ to 10 is a blow mold for producing a Container according to FIGS. 2 to 6 shown. FIG. 8 is a horizontal section through a generally designated 31 Blow mold consisting of halves 31a and 31b. The blow mold halves are shown in the expanded state. A plastic plastic hose is indicated by a dot-dash circle 32 indicated, which was extruded between the mold halves 31a, 31b.

In the mold halves there are projections 33 »which are used to Forming the pockets 10 are used. On each projection 33 there is (see FIG. 10) a cutout 34 which is dimensioned in this way is that a tube 20 (see FIG. 6) can be inserted into the cutout 34. When using the form after the Fig. Θ to 10 is proceeded as follows.

When the mold is open, tubes 20 are inserted into cutouts 34 inserted, namely as many tubes as stiffening ribs are desired. In the simplest case, it is inserted by hand, but mechanical devices can also be built that have a magazine from which the pipes

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can be removed and inserted into the cutouts 34. To After inserting the tubes 20, the plastic plastic hose 32 is extruded from an annular nozzle, the wall thickness possibly being determined can vary somewhat, namely in such a way that the wall thickness is a little larger in the area of the later stiffening ribs is than in the rest of the area. However, practical tests have shown that one can rely on such a variation in the wall thickness can also do without. Now the mold is closed until the mold halves 31a, 31b lie tightly against one another, the Hose 32 is pinched off at the top and bottom. Now compressed air is introduced into the interior of the hose 32 in a known manner introduced, which causes the plastic tube to stretch so far that it rests against the inside of the mold. During this process, the plastic wall strikes the tubes 20, so that these are now enveloped. Beyond the Pipes, i.e. in the area of the spaces 35, the plastic walls come to rest against each other and, since they are still in are in the plastic, heated state suitable for this purpose, welded to one another, the rib shape according to FIG. 6 being produced. After removing the container from the mold, for which purpose it is opened, the tubes 20 according to FIG Ribs remain or they can be pulled out, after which a rib cross-section according to FIG. 5 results.

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A rib cross-section according to FIG. 5 is also obtained when used a shape according to FIG. 11. Of which there is a total of 36 designated blow mold is shown only one half. There are pressure cylinders on the outside of the blow mold 37, 38, the piston rods 39 of which are connected to cross members 40, the other ends of which carry tubes or round rods 41 and 42, respectively. The round bars 41, 42 are passed through bores 43, 44 in the mold wall.

At the start of a blowing process, the rods 41, 42 are in the position shown. To get an offset between To exclude the rods with certainty, a guide pin 45 of the section 42 engages in a guide bore of the section 41 a. After the container is blown, will be

before opening the mold, the piston rods 39 of the pressure medium cylinder 37, 38 are extended, whereby the rods 41, 42 can be pulled out of the bore formed by its casing.

FIGS. 12 and 13 are intended to show that the concept of the invention is not only applicable to rectangular containers. in the In principle, there is no restriction to a specific container shape. In Figs. 12 and 13 is a cylindrical one Container shown in which there are Ververifungsrippen 46, which extend parallel to the surface lines of the container. At the

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Transition from the container jacket 47 to the container bottoms 48, 49 there are also pockets or projections 50 into which the ribs open. The container of Figures 12 and 13 is suitable for a use case in which the internal pressure in the container is relatively low, but it is to a certain extent Rigidity of the container is important. For example, the container according to FIGS. 12 and 13 can be placed on two support feet that have a relatively large distance from each other.

A container which is suitable for a relatively high internal pressure is shown in FIGS. 14 and 15. This is also the case around a cylindrical container with a jacket 51 and bottoms 52, 53. On the inside of the jacket 51 are circumferential Reinforcing ribs 54, which have a cross section according to FIG. 6. There are distributed over the circumference of the container Pockets or projections 55, which result from the fact that in the blow mold projections for holding curved Pipes 56 must be present.

16 shows a cross section through a stiffening rib 57, in which the opposing walls 58, 59 of a bead are welded to an inserted profile 60 made of plastic are. The inside of the container is indicated by the reference number

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specified. So it is an inwardly protruding rib. A container according to FIG. 16 is produced by that first a container is formed in which the space between the corrugated walls 58, 59 is still open. if the container has been removed from the mold, which requires it to have cooled and solidified beforehand, becomes a preheated profile 60 inserted and the bead walls 58, 59, which are also preheated, are pressed against the profile 60 and thereby welded to it.

17 is intended to serve as an example of the fact that reinforcing ribs according to the invention can also protrude outwards. The barrel-shaped container 62 has a stiffening rib 63 which consists of two layers 64, 65 which are welded to one another are.

FIGS. 18 and 19 show schematically how the stiffening rib 63 can be produced. In the total with 66 designated blow mold there are two relative to each other displaceable mold parts 67, 68. These are initially removed from one another (see FIG. 18), so that the two Plastic layers 64, 65 in the space between the parts 67, 68 can penetrate, whereby they rest on the rounded contact surfaces 67a, 68a of the molded parts 67, 68. Thereafter the parts 67, 68 are moved into the position according to FIG. 19, whereby the plastic layers 65, 66 are pressed against one another will.

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However, external stiffening ribs can also be split Shapes according to Flg. Manufacture 20 and 21. The blow mold, from who only depicted one half 1st, 1st overall with 80 designated. Each blow mold half consists essentially of three parts 81, 82, 83 »with part 82 being stationary and the parts 81, 83 are movable relative to the part 82.

At the beginning of the blowing process, the molded parts take the In Flg. 20, i.e. the parts 81, 83 have a certain distance from the fixed part 82, so that spaces 84, 85 remain between the parts. By the inflation pressure is applied to the plastic hose 86 into the spaces 84, 85. The depth of the intermediate spaces is limited by the shaped surfaces 87 »88. In a In a further work phase, the molded parts 81, 83 are moved against the molded part 82, as a result of which the plastic layers 89 and 90 or 91 and 92 are pressed together and welded together.

22 and 23 show a section from a blow mold 69, namely a section from a blow mold half. In this blow mold half there is a groove 70, in which a bar 71 can be moved. The bar 71 has two parts 72 and 73, which are connected by a heat-insulating Layer 74 are separated from one another. With this shape will worked as follows.

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Before the start of inflation are the ledges 711 of which there are usually several in the position shown in FIG. The plastic tube 75 nestles against the wall of the mold and also against the bar 71 at. Half 72 of the bar is now cooled down until the plastic layer 76 already has a certain dimensional stiffness has, but is still weldable. The molded part 73 is not cooled, so that the plastic layer 77 remains plastic. so the bar 71 is brought into the position according to FIG. 23 by means of a movement device (not shown), the internal pressure in the mold causing the plastic layer 77, which is still plastic, to adhere to the already dimensionally stable Layer 76 is pressed on, the two layers being welded to one another at 78.

The method described with reference to FIGS. 22 and 23 can also be carried out in such a way that no different cooling of layers 76 and 77 takes place. However, there is then no guarantee that the stiffening rib has a well-defined shape.

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Claims (13)

: - 24 protection claims: 1. Plastic containers, especially storage containers for Liquids, such as heating oil, which is produced in a blow molding process and has stiffening ribs created by beads are formed in the container wall, characterized in that the opposing walls (13, 14; 23 »24; 58, 69; 64, 65; 76, 77) of the beads either with one another or with a profile (25; 60) inserted into the bead, but not penetrating the container wall, are welded. 2. Container according to claim 1, characterized in that the stiffening ribs (12; 22; 46; 54; 57; 76; 77) protrude into the interior of the container. 3 · Container according to one of the preceding claims, characterized in that the opposing bead walls (13, 14) ^{are welded together up to the outer plane (16) of the container wall (5 1} ) so that the outer wall side (16) of the container is essentially is smooth. 4. Container according to one of the preceding claims, characterized in that the ribs (12; 22; 46; 54; 76, 77) on their edges are reinforced. - 25 - 7515851 07/21/77 5. Container according to claim 4, characterized in that the Reinforcement consists of an edge bead (18) which has a substantially circular cross-section. 6. Container according to one of claims 4 and 5 »characterized in that that the rib edge reinforcement is filled with an inserted profile (2Oj 25; 56). 7. Container according to claims 5 and 6, characterized in that that the inserted profile is a round bar, in the case of a profile remaining on the container, preferably a tube (20) is. 8. A container according to claim 6, characterized in that the inserted profile (25) has a shoulder (27) between the opposing walls (23, 24) of the stiffening rib (22) forming bead is sufficient, said walls (23, 24) being welded to said shoulder (27) and the shoulder (27) extends either over the entire rib height or over only part of the rib height, so that over part of the height of the ribs the opposite Walls are welded directly together. 9. Container according to claim 8, characterized in that the inserted profile (25) in the region of the extension (27) projections (28, 29) to which the plastic walls (23, 24) are adapted. 7515851 zi.07.77 - 26 - 10. Container according to one of claims 2 to 9, characterized in that the container has inwardly projecting projections (10 ¹ ; 50; 55) which form externally accessible pockets (10) and into which the stiffening ribs (12; 22; 46; 54) join. 11. Container according to claim 10, characterized in that in the case of an angular container, for example a cuboid Containers, the pockets (10) are arranged on container edges (11), preferably in such a way that the pockets (10) of both surfaces (6/4, 6/5, 4/1, 5/1) adjoining the edges are accessible. 12. Container according to one of the preceding claims, characterized in that in a container with substantially flat walls the stiffening ribs are arranged horizontally or vertically, preferably horizontally, if the larger wall dimension runs horizontally, preferably vertically, if the larger wall dimension is vertical runs (Fig. 1, 2). 13. Container according to one of claims 1 to 12, characterized characterized in that in a round or oval container, the ribs (54) are arranged circumferentially and in one to the container axis are perpendicular plane (Fig. 14, 15). 7515851 07/21/77