Tube having angled end-weld

TECHNICAL FIELD

The invention concerns a tube of polymer, weldable material with an extension in an axial direction and an extension in a radial direction, perpendicular to the axial extension, and comprising a tube body, displaying a first end with an emptying opening and a second end with a seal in the form of an end weld.

BACKGROUND OF THE INVENTION

Tubes of flexible plastic are used for a range of different packaging purposes, such as packaging of hygiene articles, cosmetics and foodstuffs. Accordingly, the contents of such tubes can be, for example, soft cheese, fish paste, hair gel, toothpaste, shampoo, lotion, liquid soap, or the like.

A problem with the commonly used tubes is that they are difficult to pack in an efficient and space-saving manner for transport and storage and that because of their shape they tend to slide around in an outer package.

Another problem with these tubes is that they are awkward to store and take up a lot of space as they are unstable and cannot be stored upright, for example on a shop shelf or in a bathroom cupboard. In addition, it is fairly important that tubes for cosmetics or the like, in particular, have an attractive appearance. Up to now, the most common way to enable upright storage has been to provide the emptying end of the tube with a closure device in the form of a screw top or a snap-on lid, which can also serve as a support on which the tube can be stood. A disadvantage of such a solution to the problem is that the tube's closure device cannot freely be formed on the basis of what gives the best possible manageability when the tube is opened

or closed. The desire to give the closure device an attractive design must also take a back seat as the form of the closure device must also be adapted to the storage function. In order to function as a support foot during upright storage of a tube, the closure device must, for example, have a sufficiently large flat support surface for the tube to be able to stand reasonably stably. As a result, such closure devices are unnecessarily large, bulky and angular.

For flexible plastic tubes, it is not possible to use special separately attached support feet arranged at the permanently sealed end of the tube, because such feet reduce the manageability of the tube and make it difficult to squeeze out the contents from the tube.

Therefore, it is a purpose of the invention to obtain a tube which can be packed in an efficient and space-saving way and which can be stored upright without the aid of the tube's closure device. A further purpose of the invention is to obtain a simple and cheap solution to the problem of storing flexible plastic tubes in an upright position and to permit upright storage without impairing the manageability and squeezability of the tube.

DESCRIPTION OF THE INVENTION

The present invention offers a tube of the type described in the introduction, which tube can be stored upright on its end weld.

A tube of weldable polymer material produced in accordance with the invention is characterised chiefly in that the end weld extends in a plane with an angle β to the axial extension which is 83 - 90°, preferably 85 - 90° and most preferably 87 - 90°, said end weld consisting of a first part and a second part, arranged at an angle α to one another, the angle α between the parts being 70° - 110°.

Providing the tube with an angled end weld achieves several advantages. The chief advantage is that the tube can be formed with a tube body that has a square/rectangular or triangular cross-section along all or parts of its

length. Such a tube body is extremely advantageous when a number of tubes are to be packed or stored together as the tubes can be stacked, or packed in a stable and space-saving way. Consequently, the stiffened tube body with the angled end weld is better adapted for packing in an outer carton holding several tubes than previously known tubes with a conventional, plane end weld. Due to the angled end weld, which preferably has an angle close to 90° but which can have a greater or lesser angle in triangular tubes, at least the part of the tube located closest to the weld also obtains a more angular, rectangular or triangular form, which economises on space when it is packed along with other tubes in an outer package. In addition, the angular shape prevents the tubes from sliding around in the outer package.

The angled end weld also constitutes a foot, or a support member, on which the tube can be balanced upright. The angling of the end weld stiffens the tube body and makes it more stable, but it also gives the end of the tube a form which facilitates handling of the tube, making it easier to squeeze out the contents of the tube compared to a conventional flexible plastic tube with a plane end weld.

The end weld is arranged in a plane that is perpendicular, or almost perpendicular, to the direction of the tube's axial extension. It can be suitable, in order to balance the weight of the tube, that the tube leans somewhat when it is upright. A suitable inclination (divergence from the perpendicular to the plane the tube stands on) is then 3°, but inclinations of up to 7° can be necessary, depending on the shape of the tube and the location of the weld in relation to the centre of gravity of the tube. Such an inclination is obtained by arranging the end weld in a plane which forms an angle β to the axial extension of the tube, which is 83 - 90°, preferably 85 - 90° and most preferably 87 - 90°. For tubes with a symmetrical cross section, for example a circular or square cross section, an inclination of 87° of the end weld in relation to the axial extension of the tube has been shown to give particularly good stability.

The length of the different parts of the end weld can easily be adapted to the size and shape of the tube in order to obtain the desired stabilising effect and support function. It is not necessary for the invention that the parts have the same length. Instead, the parts can of course have different lengths if the tube has a rectangular or triangular cross section in the area of the weld. However, particularly when several tubes are to be packed in one outer package, it is suitable, for reasons of space, that the parts of the end weld do not protrude outside the periphery of the tube. For an essentially circular tube, the parts of the end weld should be entirely situated within a square with a side corresponding to the length of the diameter of the circular tube.

According to one embodiment of the invention, the tube body has the shape of a rectangular parallelepiped with four walls extending in the longitudinal direction separated by four corners and with a rectangular cross section. In particular, the tube body can have a square cross section. A tube in the form of a rectangular parallelepiped is extremely space-saving to package, as there is essentially no wasted space between the tubes. The parts of the end weld connect to the form of the tube body and constitute a continuation in the longitudinal direction of two of the walls of the tube body. Designing the end weld in this way also results in a good support function as it gives maximum utilisation of the available cross section surface of the tube.

For reasons of stability and for production reasons, it is suitable that the length of the parts of the end weld is equal to the distance between two corners of the tube body.

The invention also concerns tubes in which the main part of the tube body is cylindrical in the longitudinal direction and has a circular cross section. The main part of the tube body is intended to mean more than 50% of the length of the tube body. In such an embodiment, the parts of the end weld should each have a length that does not exceed the cross section diameter of the tube. However, even in such an embodiment, the angled end weld conveys a

square or rectangular form to the tube body in that part of the tube body that is situated closest to the end weld.

The tube in accordance with the invention is advantageously provided with a bevelled part arranged adjacent to the end weld in the second end of the tube body. The bevelled part contributes to stiffening the tube and making it more stable as well as making it easier to squeeze and grip the tube.

In order to obtain optimum stability when the tube is stood on the angled weld, the support edge of the weld should be straight, or at least essentially straight, so that the support member forms a plane support surface.

DESCRIPTION OF THE FIGURES

The invention shall be described in further detail below with reference to the figures shown in the attached drawings, in which

Fig. 1 shows an end-welded tube in accordance with a first embodiment of the invention,

Fig. 2 shows the tube in Fig. 1 seen from the welded end

Fig. 3 shows an end-welded tube in accordance with a second embodiment of the invention,

Fig. 4 shows the tube in Fig. 3 seen from the welded end.

DESCRIPTION OF EMBODIMENTS

The tube 1 shown in Figs 1 and 2 comprises a hollow tube body 2 of flexible, weldable polymer material and a tube shoulder 3 with a dispensing opening 4 for dispensing of a product packed in the tube 1. In addition, the tube 1 has a closing device 5 in the form of a screw top. The tube has an elongated form with an extension in an axial direction 6, and in a radial direction 7 perpendicular to the axial direction 6. The tube shoulder 3 and the dispensing

opening 4 are situated at a first end 8 on the tube body 2 while the opposite second end 9 of the tube body 2 is permanently sealed with an end weld 10.

The tube body 2 consists of an injection-moulded plastic tube with a square cross section. The tube 1 can be made of, for example, polyethylene or polypropylene. As different demands are made on different parts of a tube, it is often advantageous to adapt the material in the tube accordingly.

Consequently, the tube body 2 suitably consists of polyethylene or polypropylene, while the tube shoulder 3 can consist of a fusion of polyethylene and polypropylene. Even if the entire tube 1 is formed in one and the same manufacturing step, it is consequently not necessary for the different parts to be manufactured of the same type of plastic.

Due to the fact that the tube has a square cross section, it displays four walls 11-14, which come together in four right-angled corners 15-18. Consequently, the angle α between the walls is 90° in the shown example.

After being filled with contents of some sort, the tube 1 has been sealed with an end weld 10. The end weld 10 consists of two connected parts 10a, 10b, which constitute a straight continuation of two of the sides 13, 14 of the tube body 2. The end weld 10 is thus angled in the same way as the walls 11-14 of the tube body 2, with an angle α between the parts 10a, 10b which is 90°. In the shown example, the parts 10a, 10b of the end weld 10 extend all the way between two of the corners, 17, 18 and 16, 17, of the tube body 2, and are joined in a common corner 17. The end weld 10 ends in a straight edge 19 and, due to the angled form of the end weld 10, this edge 19 forms a support member 20, on which the tube can be stood for upright storage. The edge 19 is arranged in a plane that is perpendicular, or almost perpendicular, to the axial direction 6 of the tube. It has proved to be suitable that the tube leans somewhat when it is stood on the edge 19 of the end weld in order to achieve good balance. An inclination of between 0 - 7° of the tube in relation to a perpendicular to the surface on which the tube is placed has proved to give good stability. For a tube with an essentially symmetrical cross section,

an inclination of 3° is usually optimal. In order to obtain the desired inclination, the end weld is therefore arranged in a plane which forms an angle β of 83-90° to the axial direction of the tube.

As can best be seen in Fig. 1 , the tube 1 is formed with a bevelled, concave part 21 towards the end weld 10 at the second end 9 of the tube body 2. The bevelled part 21 contributes, along with the angled end weld 10, to stiffening the tube body. In addition, the bevelled part 21 makes it easier to grip the tube and to squeeze out its contents.

The tube 1 shown in Figs 3 and 4 differs from the tube shown in Figs 1 and 2 only in the shape of the tube body 2. Accordingly, the tube 1 comprises a hollow tube body 2 of flexible, weldable polymer material and a tube shoulder 3 with a dispensing opening 4. In addition, the tube 1 has a closing device 5 in the form of a screw top. The tube has an elongated form with an extension in an axial direction 6, and in a radial direction 7 perpendicular to the axial direction 6. The tube shoulder 3 and the dispensing opening 4 are situated at a first end 8 on the tube body 2 while the opposite second end 9 of the tube body 2 is permanently sealed with an end weld 10 arranged perpendicular, or almost perpendicular (angle β) to the axial direction 6.

The tube body 2 has for the most part a cylindrical shape with a circular cross section and an envelope surface 22 without corners or edges.

Like the tube shown in Figs 1 and 2, the tube in Figs 3 and 4 has a bevelled, concave part 21 adjacent to the end weld 10 in order to stabilise the tube and to make it easier to grip the tube and to squeeze out its contents. The angled end weld 10 and the concave part 21 affect the shape in the second end 9 of the tube so that that part has an angular form with an almost square cross section near the concave part 21. The square shape gradually becomes a shape with a circular cross section in a direction towards the first end part 8 of the tube body 2.

The shown angle α between the parts 10a, 10b of the end weld 10 in Figs 3 and 4 is ca. 90°. However, it is possible to make tubes with a certain divergence from a right angle between the parts of the end weld. The angle would then suitably be from 85° to 95°. A square tube, or a tube with at least a mainly right-angled end weld provides several advantages. A right-angled weld makes it easier to manufacture the tube and is advantageous when several tubes are packed together in a larger outer package.

With regard to packaging, in order that the tubes take up as little space as possible when several tubes are packed together in a larger outer package, it is suitable not to make the parts 10a, 10b of the end weld so long that they project outside the envelope surface of the tube body, or at least outside an imagined square containing the tube body. This means that the parts 10a, 10b on a cylindrical tube should not be longer than the diameter of the tube.

The end welds have been shown with sharp corners. However, it is possible within the framework of the invention to form the welds with somewhat rounded corners. It is preferred that the weld parts are straight, apart from any corrugations. However, slightly curved weld parts with a large curve radius can be used, as long as a distinct, measurable angle is present between the weld parts.

The invention shall not be considered to be limited to the embodiments described here. The shown closing device in the form of a screw top is, of course, not necessary for the invention, all types of closing arrangements such as a snap-on lid, a push-on cork or a cork that is inserted into the dispensing opening. Furthermore, there exist various types of security corks which can be used if so desired.