HEAD FOR A FLEXIBLE TUBE COMPRISING A PERIPHERAL WELDING SURFACE

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to French Application No. 2408592, filed Aug. 2, 2024, the contents of which is incorporated herein by reference in its entirety.

Technical Field of the Invention

The present invention relates to a head for a tube comprising a flexible skirt, the head having a main axis and comprising:

• • a central portion equipped with a dispensing orifice,
  • an annular shoulder which extends from the central portion in a substantially radial direction,
  • an exposed internal annular portion of the shoulder which is configured to be visible after assembly of the head with the flexible skirt;
  • an annular peripheral bearing face of the shoulder against which an upper end segment of the flexible skirt is intended to be folded back to enable it to be welded;
  • an annular shoulder face projecting with respect to the peripheral bearing face and facing radially outwards which delimits the peripheral bearing face and the exposed portion.

Prior Art

Such tubes are designed in particular to contain pasty products, ointments or creams. These include cosmetics and skincare products.

The flexible tubes have traditionally been provided with a rigid tube head. The rigid head comprises a shoulder around the centre of which is an orifice for dispensing the product contained in the tube. Such a head contributes to the ease of use of the tube by providing a better grip for the user and allowing controlled distribution of the product they contain.

When manufacturing such a flexible tube, it is known to produce a flexible tubular skirt and the rigid head separately. The flexible skirt is made, for example, by winding and welding a laminated sheet or by extrusion.

The head is fitted into one end, known as the upper end, of the skirt, then a segment of the upper end of the skirt is folded down against a peripheral bearing face of the shoulder and welded thereto.

The shoulder's peripheral bearing face, for example, has the shape of a rabbet bounded internally by an annular shoulder face oriented outward. The shoulder face is generally parallel to the axis of the tube.

The rabbet has a height slightly greater than the thickness of the wall of the flexible skirt. During welding, the folded segment of the flexible skirt is pressed against the peripheral bearing face and some of the material flows towards the shoulder face.

The height of the shoulder face is designed so that the material flowing towards the shoulder face does not form a weld bead projecting from the surface of the exposed portion of the shoulder. This is essential to give the weld an aesthetic appearance that will convey a high-quality image of the product to the buyer.

This configuration requires a specific head to be designed for each skirt thickness, which can vary between 0.14 mm and 0.3 mm depending on the design of the tube.

There is therefore a need to be able to adapt the same tube head to several thicknesses of flexible skirt while maintaining an aesthetic weld.

SUMMARY OF THE INVENTION

The present invention provides a head for a tube comprising a flexible skirt, the head comprising:

• • a central portion equipped with a dispensing orifice,
  • an annular shoulder which extends from the central portion in a substantially radial direction,
  • an exposed internal annular portion of the shoulder which is configured to be visible after assembly of the head with the flexible skirt;
  • an annular peripheral bearing face of the shoulder against which an upper end segment of the flexible skirt is intended to be folded back to enable it to be welded;
  • an annular shoulder face projecting with respect to the peripheral bearing face and facing radially outwards which delimits the peripheral bearing face and the exposed portion;
    characterised in that the annular shoulder face has, in axial section, an opening angle greater than 125° with respect to the peripheral bearing face.

According to another embodiment of the head according to the teachings of the invention, the annular shoulder face has, in axial section, an opening angle greater than 140° with respect to the peripheral bearing face.

According to another embodiment of the head according to the teachings of the invention, the annular shoulder face has, in axial section, an opening angle of less than 155° with respect to the peripheral bearing face.

According to another embodiment of the head according to the teachings of the invention is that the annular shoulder face has, in axial section, an angle equal to 148° with respect to the peripheral bearing face.

According to another embodiment of the head according to the teachings of the invention, the peripheral bearing face extends, in axial section, parallel to at least one external peripheral part of the exposed portion of the shoulder.

According to another embodiment of the head according to the teachings of the invention, the bearing face is extended axially downwards by an axial sleeve which is configured to be fitted into the flexible skirt and which is connected to the bearing face by a rounded fillet.

The invention also proposes a flexible tube comprising a head made in accordance with the teachings of the invention and a flexible skirt, an upper end segment of which is folded back onto the peripheral bearing face and welded against said peripheral bearing face.

According to another embodiment of the tube according to the teachings of the invention, the shoulder face has a height, taken orthogonally to the peripheral bearing face, which is greater than or equal to the nominal thickness of the wall of the flexible skirt before it is welded to the head.

According to another embodiment of the tube according to the teachings of the invention is that the height of the shoulder face is between 0.40 mm and 0.70 mm.

According to another embodiment of the tube according to the teachings of the invention, the height is equal to 0.40 mm and the nominal thickness of the wall of the skirt before it is welded to the head is between 200 μm and 400 μm.

According to another embodiment of the tube according to the teachings of the invention, the height is equal to 0.70 mm and the nominal thickness of the wall of the skirt before it is welded to the head is between 200 μm and 500 μm.

BRIEF DESCRIPTION OF THE FIGURES

Further characteristics, purposes and advantages of the invention will be apparent from the following description, which is purely illustrative and not limiting, and which should be read in conjunction with the appended drawings briefly described below.

FIG. 1 is a perspective view showing a tube comprising a head made according to the teachings of the invention.

FIG. 2 is a perspective view showing the head of the tube in FIG. 1.

FIG. 3 is an axial half-section view showing the head shown in FIG. 2.

FIG. 4 is a similar view to that of FIG. 2 in which the head was fitted into a flexible skirt for their assembly.

FIG. 5 is a similar view to FIG. 4, in which a nozzle blows hot air between the end segment of the skirt and a peripheral bearing face of the head.

FIG. 6 is a similar view to FIG. 4, in which an end segment of the skirt has been folded back against a peripheral bearing face of the head.

FIG. 7 is a similar view to FIG. 5, in which the skirt has been welded to the peripheral bearing face of the head.

DETAILED DESCRIPTION OF THE INVENTION

For the remainder of the description, elements with an identical structure or similar functions will be designated by a same reference.

For the remainder of the description, we will adopt an axial direction which corresponds in the figures to that of the main axis “A” of the tube head. Radial directions orthogonal to the axial direction will also be adopted, radiating from the main axis. Finally, the circumferential direction is orthogonal to the axial and radial directions.

The terms “upper” and “lower” are used in reference to the representation of the tube in FIG. 1, in which the head is at the top and the skirt is at the bottom. These terms are used as a geometric reference point with no relation to the direction of the Earth's gravity.

FIG. 1 shows a tube 10 designed to contain a liquid or pasty product, in particular a cosmetic or personal care product.

The tube 10 has a body 11 made of a tubular skirt 12 of flexible and deformable material, the upper end of which is closed by a head 14. The tubular skirt 12 has a main axis “A”.

The skirt 12 comprises a wall with at least one internal weld layer intended to be in contact with the tube head 14. The weld layer is made of a plastic material such as polypropylene (PP) or polyethylene (PE).

The skirt 12 is made, for example, by winding and welding the two edges of a sheet of laminate together, in particular with an overlap.

Alternatively, the skirt 12 is produced directly in its tubular configuration by extrusion.

The tube head 14, particularly visible in FIGS. 2 and 3, has a central principal axis “A” which passes substantially through its centre. The main axis “A” is coaxial with the axis of the tubular skirt 12.

The tube head 14 is made from a single piece of material. The head 14 is preferably made of a rigid plastic material, such as high density polyethylene (HDPE) or polypropylene (PP). It is made, for example, by injection moulding in a mould.

The head 14 comprises a central portion 16 equipped with an orifice 18 for dispensing the product contained in the tube 10. A user can discharge the contents of the tube 10 through the dispensing orifice 18 by squeezing the body 11.

The central portion 16 is in the form of a tubular neck which extends axially upwards. The neck is arranged coaxially with the main axis “A”. The neck is axially traversed by the dispensing orifice 18.

Alternatively, the central portion 16 is an upper wall orthogonal to the main axis “A”. The top wall is penetrated by the distribution orifice 18, which may be eccentric with respect to the main axis “A” or may be coaxial with the main axis “A”.

The dispensing orifice 18 can be closed by a cap (not shown) and/or by a peelable or tearable seal. The cap can be made as a separate piece from the head 14 or as an integral piece of the head 14.

The head 14 also comprises an annular shoulder 20 which allows to connect the central portion 16 of the head 14 to the tubular skirt 12. The annular shoulder 20 extends from the central portion 16 in a direction substantially radial to the main axis.

The shoulder 20 comprises a first internal annular portion, known as the exposed portion 22, which is configured to be visible once the head 14 has been assembled with the flexible skirt 12.

This exposed portion 22 generally has a truncated cone shape which extends downwards from the central portion 16 of the head 14. For example, but without limitation, the exposed portion 22 has, in axial section, an angle y of between 25° and 35°, preferably 30°, with respect to a plane orthogonal to the main axis “A”.

Alternatively, the exposed portion 22 may have a complex shape in axial section, with rounded and/or stepped edges. In this case, a periphery of the exposed portion 22 has, in axial section, a rectilinear shape having an angle of between 25° and 35°, preferably 30°, with respect to a plane orthogonal to the main axis.

Alternatively, when the periphery of the exposed portion 22 is fillet-shaped, the tangent forms an angle of between 25° and 35°, preferably 30°, relative to a plane orthogonal to the main axis.

The shoulder 20 also comprises a hidden portion 24 which is configured to be fitted inside the flexible skirt 12 as shown in FIG. 4. The hidden portion 24 is bounded at the bottom by a lower end edge 25 which extends in a plane orthogonal to the main axis “A”.

The hidden portion 24 comprises an annular peripheral bearing face 26. In axial section, the peripheral bearing face 26 has a rectilinear shape. It is turned axially upwards so as to form an angle with the axial direction in axial section. An upper end segment 12A of the flexible skirt 12 is configured to be folded back to enable it to be welded.

For example, in axial section, the peripheral bearing face 26 has an angle of between 25° and 35°, preferably 30°, with respect to a plane orthogonal to the main axis “A”.

The peripheral bearing face 26 here extends, in axial section, parallel to the exposed portion 22.

For example, in axial section, the peripheral bearing face 26 has a width “l” of at least 0.20 mm. The width “1” is for example between 0.40 mm and 0.60 mm, preferably between 0.50 mm and 0.55 mm, for example 0.52 mm.

The head 14 also comprises an annular shoulder face 28 projecting upwards from the peripheral bearing face 26. The shoulder face 28 is inclined so as to face radially outwards and upwards. It delimits the peripheral bearing face 26 of the exposed portion 22. More particularly, a lower edge 28A of the shoulder face 28 delimits the peripheral bearing face 26 on the inside.

The peripheral bearing face 26 is stepped in relation to the periphery of the exposed portion 22 of the shoulder 20. Thus, an upper end edge 28B of the shoulder face 28 internally delimits the exposed portion 22. The peripheral bearing face 26 and the shoulder face 28 thus form a rabbet to receive the folded end segment 12A of the skirt 12.

As shown in FIG. 3, the annular shoulder face 28 has, in axial section, an opening angle β greater than 125° with respect to the peripheral bearing face 26. Preferably, said one opening angle B is greater than 140°. Preferably, the opening angle β is less than 155°. Said opening angle β is, for example, 148°.

The opening angle β is constant along the entire length of the shoulder face 28.

This specific inclination of the shoulder face 28 creates sufficient space to receive the material of the wall of the flexible skirt 12 which flows inwards when it is welded to the head 14, as will be explained in more detail later.

In addition, the hidden portion 24 of the head 14 comprises an axial sleeve 30 which extends the peripheral bearing face 26 axially downwards. This sleeve 30 is configured to be fitted into the flexible skirt 12 to ensure that the head 14 is held securely in the flexible skirt 12. The sleeve 30 is connected to the peripheral bearing face 26 by a rounded edge 32 which prevents the formation of folds in the skirt 12 when its end segment 12A is folded back onto the peripheral bearing face 26. A lower end edge of the sleeve 30 forms the lower end edge 25 of the head 14 which extends in a plane orthogonal to the main axis “A”.

The shoulder face 28 has a height “h”, taken orthogonally to the peripheral bearing face 26, which is greater than the nominal thickness “e” of the wall of the flexible skirt 12. The nominal thickness “e” of the wall of the skirt 12 is defined as its thickness “e” measured before it is welded to the head 14. During welding, the wall is heated and pressed against the peripheral bearing face 26, which reduces its thickness “e”. After welding, the folded segment 12A of the skirt 12 has a thickness “e” less than or equal to, preferably less than, the height “h” of the shoulder face 28.

The height “h” of the shoulder face 28 is, for example, between 0.40 mm and 0.70 mm. Preferably, the shoulder face 28 has a height “h” of 0.40 mm.

A same head 14 therefore is likely to be associated with skirts 12 having a thickness “e” less than or equal to, preferably less than, the height “h”.

For example, a same head 14 having a shoulder face 28 of height “h” of 0.40 mm is likely to be assembled with skirts 12 having a thickness “e” of between 200 μm and 400 μm.

According to another embodiment, a same head 14 having a shoulder face 28 of height “h” of 0.70 mm is likely to be assembled with skirts 12 having a thickness “e” of between 200 μm and 500 μm.

During manufacture of the tube 10, the head 14 produced according to the teachings of the invention is inserted into the skirt 12 previously shaped as a tube, as shown in FIG. 4.

As shown in FIG. 6, an upper end segment 12A of the skirt 12 is folded back against the peripheral bearing face 26 so that the upper end edge 12B of the skirt 12 is substantially aligned with the lower edge 28A of the shoulder face 28. The bearing face 26 and the upper end segment 12A of the skirt 12 have been heated beforehand to enable them to be welded. Thus, during the welding operation, a free space 34 having a triangular shape in axial section is reserved between the shoulder face 28 and the end edge 12B of the skirt 12.

Then, as shown in FIG. 7, at the end of the welding process, the skirt 12 is welded to the peripheral bearing face 26.

During this operation, the segment 12A of the skirt 12, folded back against the peripheral bearing face 26, is pressed against the latter. The material 36 forming the skirt 12, made malleable by the heating undergone during the welding operation, flows towards the free space 34 which has sufficient volume to be able to accommodate different quantities of flowing material 36 depending on the thickness “e” of the wall of the skirt 12. The material 36 having thus flowed, fills the free space 34 so as to be flush with the periphery of the exposed portion 22 of the shoulder 20. In this way, the folded and welded segment 12A of the flexible skirt 12 extends radially in direct line with the exposed portion 22 of the shoulder 20.

Preferably, the skirt 12 is welded to the peripheral bearing face 26 by heat welding using an annular nozzle 33 which blows hot air “F” towards the bearing face 26 before the segment 12A of the skirt 12 has been folded back, as shown in FIG. 5. The nozzle 33 is generally offset radially outwards and blows hot air simultaneously across the entire bearing face 26. The hot air softens the material making up the skirt so that it can be welded to the bearing face 26.

The angle β of inclination of the shoulder face 28 allows to promote the flow of hot air towards the bearing face 28.

The angle β of inclination of the shoulder face 28 also allows a certain degree of freedom to orientate the nozzle, particularly in the case where the head 14 is provided with a flip top made in one piece with the head 14. The welding operation is generally carried out with the cap closed. The cap is equipped with an opening tab that extends radially, projecting above the shoulder, allowing the thumb to apply pressure to open the cap. The space left free by the tab does not allow the nozzle to be positioned directly above the bearing face. The inclination of the bearing face allows the nozzle to be arranged slightly offset radially outwards.

In addition, the height “h” of the shoulder face 28 is very significantly higher than on the heads in the state of the art. The angle β of inclination of the shoulder face 28 allows sufficient radial space to be left for the nozzle even when the tube 10 has not been correctly centred with respect to the nozzle.