DE20311316U1 - Cardboard packaging case has two sections with interlocking edge formations to define closed interior - Google Patents

Abstract

The cardboard packaging case (1) has at least two sections (2,3) to define a closed inner volume. The opposing section edges (4-7) of the cases have integral interlocking formations to retain the section edges together. The formations keep the edges aligned under load.

Description

July 22, 2003

Paul & Co. PAU-014

Owner K. Kunert & Söhne GmbH & Co. Boe/-

97770 Wildflecken

Cardboard tube, especially for packaging purposes

The invention relates to a cardboard tube according to the preamble of claim 1.

Cardboard tubes are known from the prior art which are produced by spirally winding individual paper or cardboard layers onto one another and which have a substantially cylindrical shape. In particular, when such cardboard tubes are to be used to package long objects, for example, the cardboard tubes are radially or diametrically severed to form two semi-cylindrical partial shells. To package the objects, they are first placed in a cylindrical partial shell, after which the second cylindrical partial shell is placed on top in such a way that the radially extending edge surfaces of the two partial shells facing one another come into contact with one another. The two partial shells are then usually fixed in place using a packing or tensioning band that runs around the cardboard tube.

The disadvantage here is that even with a low radial load, especially in the cutting plane formed by the edge surfaces, the two partial shells slide away from each other, which ultimately

the packaging becomes unusable or at least has to be reassembled.

To avoid this, it is also known to use plastic profile rails with an H-shaped cross-section, into which the opposing edge areas of the two partial shells are inserted and thus radially fixed. However, such profile rails are cumbersome to handle, expensive and also require separate disposal.

Based on this prior art, it is the object of the present invention to provide a generic cardboard sleeve in which such a profile rail can be dispensed with.

This object is achieved by a cardboard sleeve according to the teaching of claim 1.

Advantageous embodiments of the invention are the subject of the subclaims.

The cardboard sleeve according to the invention, which can be used in particular, but by no means exclusively, for packaging purposes, has, in a manner known at least two partial shells, which can be brought into contact with one another to form a sleeve which is essentially closed in the circumferential direction in such a way that the edge surfaces of adjacent partial shells facing one another come into contact with one another directly or indirectly.

In contrast to the prior art, however, in which the edge surfaces can slide away from one another due to their design when subjected to radial load, particularly in the parting plane, according to the invention edge surfaces are designed as locking surfaces at least in sections. "Locking" in the sense of the present invention means preventing the opposing edge surfaces and thus the partial shells from sliding away from one another. This allows for a

Profile rail, as is necessary in the current state of technology, can be dispensed with.

The shape of the cardboard sleeve, in particular its cross-sectional shape, is initially basically arbitrary. According to a particularly preferred embodiment, in particular with regard to the comparatively simple production by winding, the cardboard sleeve is essentially circular-cylindrical, with the partial shells being designed as cylindrical partial shells.

The cylindrical cardboard sleeve can be formed, for example, by three or more partial shells. Preferably, however, the partial shells are designed as cylindrical half shells. This enables the partial shells to be assembled simply and easily to form a closed cardboard sleeve.

According to a preferred embodiment, the edge surfaces of adjacent partial shells facing each other have locking elements that are complementary in terms of shape and function and that engage behind each other essentially in the radial direction. These locking elements can be formed integrally on the edge surfaces and/or formed into the edge surfaces, for example. This makes it easy to lock the partial shells in the radial direction, in particular the parting plane.

The type of locking elements is basically arbitrary, as long as there is sufficient radial fixation both when assembling the partial shells and after tightening with a packing or tensioning band. In a simple way, for example, the edge surfaces can have a sawtooth-like shape in cross-section, relative to the longitudinal axis of the cardboard tube, with the sawtooth-like projections forming the locking elements. The sawtooth-like projections or the resulting depressions can be created by milling the edge surfaces.

According to a further embodiment, the locking elements can be formed by at least one web-like or flange-like shoulder that protrudes from the edge surface in cross-section relative to the longitudinal axis of the cardboard sleeve. For example, the shoulder can be arranged alternately on the opposite edge surfaces of two adjacent partial shells to form a shape- and function-complementary engagement on the opposite edge surfaces of two adjacent partial shells in such a way that it runs radially outward on the first edge surface relative to the cross-section and radially inward on the opposite second edge surface. However, a shoulder is also conceivable that runs in the radial center of an edge surface and, when the two partial shells are put together, engages in a groove in the opposite edge surface or is radially engaged there by two shoulders that run radially inward and outward.

According to a further embodiment, both opposing edge surfaces each have at least one groove-like depression, at least in sections, into which at least one locking element can be introduced in such a way that the locking element engages in the opposing depressions of two opposing edge surfaces in the manner of a tongue and groove connection. In other words, while in the embodiment described above the locking element was formed as a single piece, in this embodiment a separately manufactured and assembled locking element is used. For example, a cardboard or fiber strip can be used, which results in uniform disposal after intended use.

According to a particularly preferred embodiment, the mutually facing edge surfaces of adjacent partial shells are designed as inclined surfaces that are essentially parallel to one another in such a way that the edge surfaces in cross section, relative to the longitudinal axis of the cardboard tube, are angled relative to the respective radius, whereby

the angles of the two edge surfaces of a partial shell are opposite to the respective radius. In other words, this means that, in contrast to the state of the art, in which the edge surfaces run radially or diametrically, a simple change in the edge surface angle results in locking or mutual position fixation of the partial shells in a self-centering manner. This means that no profile rails or separate locking elements are required, and no profiling of the edge surfaces themselves is required.

In order to achieve the desired locking or fixing effect, it is initially only important that the edge surface angles are inclined in opposite directions as described above. These opposite edge surface angles of a partial shell can be of different sizes. Preferably, however, the angles of the two edge surfaces of a partial shell are essentially the same in terms of amount, i.e. the same size, in relation to the respective radius.

The size of the edge surface angle ultimately depends on the desired locking effect, i.e. the radial load to be absorbed in the parting plane, and can be determined in simple tests by a specialist for the respective desired application. The angles are preferably between 20 and 60 degrees, preferably between 35 and 50 degrees.

First of all, it is basically irrelevant whether the cardboard tube in question is a wound tube or a tube produced in another way, for example by pressing paper fiber material. In particular, it is also conceivable that the partial shells are produced separately. According to a particularly preferred embodiment, however, the cardboard tube essentially consists of a plurality of paper or cardboard layers that are wound spirally or straight in a substantially cylindrical manner on top of one another, the partial shells being formed by cutting open the cylindrically wound cardboard tube.

·

This allows for particularly simple and economical production of the cardboard sleeve or the partial shells according to the invention.

The dimensions of the cardboard tube depend essentially on the intended use. Cardboard tubes according to the invention are used in lengths from a few centimeters up to 12.5 m and more. The wall thicknesses of the cardboard tube or the partial shells are preferably from approx. 6 mm up to 20 mm and more.

After the cardboard sleeve has been formed by the partial shells and, if necessary, fixed to one another by means of tensioning or packing straps or the like, the cardboard sleeve can be closed at the front by a lid.

In the following, the invention is explained in more detail using drawings showing only exemplary embodiments. It shows

Fig. 1 shows a schematic cross-section of a

State-of-the-art cardboard sleeve with H-shaped profile rail;

Fig. 2 in a representation corresponding to Fig. 1 a

first embodiment of a cardboard tube according to the invention with oppositely inclined edge surfaces;

Fig. 3 in a schematic enlarged view the individual

the opposite edge surfaces of two partial shells according to a second embodiment of the invention;

Fig. 4 in a representation corresponding to Fig. 3 the

opposite edge surfaces of two partial shells according to a third embodiment of the invention;

Fig. 5 in a representation corresponding to Fig. 3 the

opposing edge surfaces of two partial shells according to a fourth embodiment of the invention and

Fig. 6 in a representation corresponding to Fig. 3 the

opposite edge surfaces of two partial shells according to a fifth embodiment of the invention.

Fig. 1 shows a cardboard sleeve according to the prior art. The cardboard sleeve 1 has an essentially circular cylindrical shape and is formed by the two partial shells 2 and 3 in the form of cylindrical half-shells. The edge surfaces 4 and 5 or 6 and 7 run parallel to one another and, in relation to the cross section of the cardboard sleeve 1, in a radial or diametrical direction. In order to prevent the partial shell 2 from slipping off the partial shell 3 and vice versa in the event of a load F or a corresponding load component of an obliquely acting force F', an H- profile rail 8 made of plastic is arranged in both separating joints between the partial shells 2 and 3, which runs over the entire length of the cardboard sleeve 1 and is indicated by dashed lines, into which the edge surfaces 4

and 5 or 6 and 7. These profile rails 8 are expensive, difficult to install and must be disposed of separately.

In the following illustrations of the embodiments of the invention, identical parts or features are identified by the same reference numerals for better understanding.

The circular cylindrical cardboard tube 1 according to the first embodiment of the invention shown in Fig. 2 also has two partial shells 2 and 3 in the form of cylinder half shells with the edge surfaces 4 and 5 or 6 and 7. In contrast to the prior art shown in Fig. 1, the edge surfaces 4 and 5 or 6 and 7

However, they are not radial or diametrical, but are designed as pairs of parallel inclined surfaces which are angled in opposite directions to the radius 9 or 10 by the angle a\ or oc2. The angles cq and (*2 are the same size in the embodiment shown in Fig. 2.

If, for example, after an item to be packaged, such as a blind or the like, has been placed in the partial shell 3, the partial shell 2 is placed as a "lid" on the partial shell 3, the edge surfaces 4 and 5 come to rest on the parallel edge surfaces 6 and 7. Due to the opposing inclination of the edge surfaces 4 and 5 or 6 and 7, the two partial shells 2 and 3 are securely fixed in position to one another without the need for a supporting profile rail. In a manner known per se, the two partial shells 2 and 3 can then be firmly connected by clamping the two partial shells 2 and 3 with a tensioning or packing tape (not shown).

The embodiment shown in Fig. 3 has locking elements 11 and 12 in the form of sawtooth-like projections in cross-section, which are integrally formed on the facing edge surfaces 4 and 6 of the partial shells 2 and 3. The locking elements 11 and 12 of the edge surfaces 4 and 6 are arranged and shaped in such a way that when the partial shells 2 and 3 and thus the edge surfaces 4 and 6 are placed on top of one another, the locking elements 11 and 12 engage behind one another in a form and function that is complementary in the radial direction and reliably prevents the edge surfaces 4 and 6 and thus the partial shells 2 and 3 from sliding away from one another in an undesirable manner in the radial direction.

In the embodiment according to Fig. 4, the edge surfaces 4 and 5 are each provided with a web-like or flange-like shoulder 13 or 14, which protrudes from the edge surface 4 or 5. The shoulder

13, based on the cross-sectional area, is arranged radially on the outside of the edge surface 4 and the step 14 is arranged radially on the inside of the edge surface 6, so that in the cross-section there are stepped edge surfaces 4 and 6 in opposite directions. The radial engagement of the two steps 13 and 14 ensures a reliable radial position fixation of the two partial shells 2 and 3 to one another, without the need for an additional profile.

The embodiment according to Fig. 5 basically corresponds in its structure and effect to the embodiment according to Fig. 4, but the shoulder 13 of the edge surface 4 of the partial shell 2 is arranged in the radial direction centrally in the edge surface 4. The opposite edge surface 6 of the partial shell 3 is provided with two shoulders 14 in such a way that the two shoulders 14 form a recess in the middle between them, into which the shoulder 13 engages when the two partial shells 2 and 3 are joined together. This results in a particularly reliable radial fixation both radially inwards and radially outwards.

Finally, in the embodiment according to Fig. 6, the edge surfaces 4 and 6 of the two partial shells 2 and 3 are each provided with a groove-like recess 15 and 16, respectively, which are arranged so that they lie opposite one another when the partial shells 2 and 3 lie on top of one another. A locking element in the form of a spring 17 is introduced into the groove-like recess 16. When the two partial shells 2 and 3 are joined together, the spring 17 engages in the groove-like recess 15 of the edge surface 4 of the partial shell 2, whereby the two partial shells 2 and 3 are radially fixed to one another.

Claims (13)

1. Cardboard sleeve ( 1 ), in particular for packaging purposes, with at least two partial shells ( 2 , 3 ) which can be brought into contact with one another to form a sleeve which is essentially closed in the circumferential direction in such a way that the mutually facing edge surfaces ( 4 , 5 ; 6 , 7 ) of adjacent partial shells ( 2 , 3 ) come into contact with one another directly or indirectly, characterized in that edge surfaces ( 4 , 5 ; 6 , 7 ) are designed as locking surfaces at least in sections. 2. Cardboard sleeve according to claim 1, characterized in that the cardboard sleeve ( 1 ) is substantially circular-cylindrical and the partial shells ( 2 , 3 ) are designed as cylindrical partial shells. 3. Cardboard tube according to claim 2, characterized in that the partial shells ( 2 , 3 ) are designed as cylindrical half-shells. 4. Cardboard sleeve according to one of claims 1 to 3, characterized in that the mutually facing edge surfaces ( 4 , 5 ; 6 , 7 ) of adjacent partial shells ( 2 , 3 ) have locking elements ( 11 , 12 ; 13 , 14 ; 15 , 16 , 17 ) which engage behind one another essentially in the radial direction and are complementary in terms of shape and function. 5. Cardboard sleeve according to claim 4, characterized in that the locking elements ( 11 , 12 ; 13 , 14 ) are integrally formed on the edge surfaces ( 4 , 5 ; 6 , 7 ) and/or are molded into the edge surfaces ( 4 , 5 ; 6 , 7 ). 6. Cardboard sleeve according to claim 4 or 5, characterized in that the edge surfaces ( 4 , 5 ; 6 , 7 ) have a sawtooth-like shape in cross-section, relative to the longitudinal axis of the cardboard sleeve ( 1 ), wherein the sawtooth-like projections form the locking elements ( 11 , 12 ). 7. Cardboard sleeve according to claim 4 or 5, characterized in that the locking elements ( 13 , 14 ) are each formed by at least one shoulder projecting from the edge surface (4, 6, 7) in cross-section relative to the longitudinal axis of the cardboard sleeve ( 1 ). 8. Cardboard sleeve according to claim 4, characterized in that the edge surfaces ( 4 , 5 ; 6 , 7 ) each have, at least in sections, at least one groove-like depression ( 15 , 16 ) into which at least one locking element ( 17 ) can be introduced such that the locking element ( 17 ) engages in the opposing depressions ( 15 , 16 ) of two opposing edge surfaces ( 4 , 5 ; 6 , 7 ) in the manner of a tongue and groove connection. 9. Cardboard sleeve according to one of claims 1 to 3, characterized in that the mutually facing edge surfaces ( 4 , 5 ; 6 , 7 ) of adjacent partial shells ( 2 , 3 ) are designed as inclined surfaces which are essentially parallel to one another in such a way that the edge surfaces ( 4 , 5 ; 6 , 7 ) in cross section, based on the longitudinal axis of the cardboard sleeve ( 1 ), are angled relative to the respective radius ( 9 , 10 ), wherein the angles (α ₁ , α ₂ ) of the two edge surfaces ( 4 , 5 ; 6 , 7 ) of a partial shell ( 2 , 3 ) are opposite to the respective radius ( 9 , 10 ). 10. Cardboard sleeve according to claim 9, characterized in that the angles (α ₁ , α ₂ ) of the two edge surfaces ( 4 , 5 ; 6 , 7 ) of a partial shell ( 2 , 3 ) with respect to the respective radius ( 9 , 10 ) are essentially equal in magnitude. 11. Cardboard sleeve according to claim 9 or 10, characterized in that the angles (α ₁ , α ₂ ) are between 20 and 60 degrees, preferably between 35 and 50 degrees. 12. Cardboard tube according to one of claims 1 to 11, characterized by a plurality of paper or cardboard layers which are wound spirally or straight in a substantially cylindrical manner on one another, the partial shells ( 2 , 3 ) being formed by cutting open the cylindrically wound cardboard tube ( 1 ). 13. Cardboard sleeve according to one of claims 1 to 12, characterized in that the wall thickness of the cardboard sleeve ( 1 ) is between 6 mm and 20 mm, preferably between 8 and 12 mm.