FR3050679A1 - MOLDING APPARATUS FOR FORMING A RETENTION DEVICE - Google Patents

Abstract

The invention relates to a molding apparatus (10) for forming a retaining device. The molding apparatus (10) comprises a molding strip (12) and a molding support (24). The molding strip (12) has an inner face (14), an outer face (16), a plurality of through cavities (18) extending from the outer face (16) to the inner face (14), the strip mold (12) extending in a longitudinal direction (X) and having a transverse direction (Y) perpendicular to the longitudinal direction (X) and a height direction (Z) perpendicular to the longitudinal direction (X) and in the transverse direction (Y). The inner face (14) is configured to bear against a molding face (26) of the molding support (24), in which the inner face (14) of the molding strip (12) and / or the face of molding (26) of the molding support (24) comprises an array of passages, the network of venting passages connecting the cavities (18) to one another when the molding strip (12) bears against the molding support (24). ).

Description

BACKGROUND OF THE INVENTION [0001] The present disclosure relates to the field of restraint devices and in particular the field of devices for manufacturing hook retainers.

Conventional apparatus for producing closure systems comprising self-gripping elements such as hooks conventionally use means for dispensing a plastic material in cavities formed on a molding roll or in a strip of plastics. molding.

[0003] Moreover, the distribution of plastic material in the cavities is carried out so that a continuous ribbon forming a base for the hooks or preforms of molded hooks is formed on the side of the distribution means of the plastic material. in the cavities.

The distribution of the plastic material in the cavities can be achieved by pressing the extruded plastic into the cavities using, for example, a pressing roller or by direct injection of plastic into the cavities.

There are known hook retaining manufacturing apparatus comprising a molding strip, which is a band closed on itself and tensioned on rotating drive means, for example two rollers. The plastic material is injected or pressed into the cavities of the molding strip opposite one of the drive rollers or facing a molding support. The drive roll or the molding support thus close the cavities of the molding strip vis-à-vis the location where is injected or pressed the plastic material to define a given volume of plastic material intended to form a preform of the hooks or the hooks themselves.

However, in view of the economic requirements, the running speeds of the molding strip are such that during the distribution of the plastic material in the cavities, it is possible that each cavity is not filled with the material plastic and that an air pocket is trapped in the cavities. As a result, not all preforms or hooks are optimally formed on the base and the hook retainer may be less efficient.

OBJECT AND SUMMARY OF THE INVENTION [0007] The present disclosure aims at remedying at least part of these disadvantages.

For this purpose, the present disclosure relates to a molding apparatus for forming a retaining device, the molding apparatus comprising a molding strip and a molding support, the molding strip having an inner face, an outer face, a plurality of through cavities extending from the outer face to the inner face, the molding strip extending in a longitudinal direction and having a transverse direction, perpendicular to the longitudinal direction, and a height direction, perpendicular to the longitudinal direction and to the transverse direction, the inner face being configured to bear against a molding face of the molding support, in which the internal face of the molding strip and / or the molding face of the support of molding comprises a network of passages, the network of passages forming a vent and connecting the cavities together when the molding strip bears against the molding support.

The molding strip is for example a molding strip closed on itself and stretched on rotating drive means of the molding strip, for example two rotary drive rollers. One of the rotational drive rollers of the molding strip can serve as a molding support. The molding support may also be distinct from the rotating drive means.

In the molding apparatus, the injection of plastic into the cavities is performed by the outer face of the molding strip, opposite the molding support, that is to say when the inner face of the molding strip bears against the molding face of the molding support.

Through the network of passages forming a vent and connecting the cavities together when the molding strip bears against the molding support, that is to say that the inner face of the molding strip bears against the molding face of the molding support. the cavities are not completely closed during the injection of the plastic material. The cavities are therefore not airtight.

Thus, during the injection of the plastic into the cavities, even at high speed of travel of the molding strip, the plastic material injected into each cavity pushes the air present in each cavity to the network of passages and the air escapes to the atmosphere through the vent formed by the network of passages between the molding strip and the molding support. The air can escape to the atmosphere through the cavities which are not filled with plastic and which are connected to the cavities being filled by the network of passages. The air can also escape to the atmosphere from the lateral sides of the strip of the molding strip. It is then possible to manufacture retaining devices at high speeds and considerably reduce the pressure required to fill the molding cavities.

It is understood that the air is no longer enclosed in the cavity by the plastic and therefore has no resistance to filling the cavity with the plastic material. Also, it ensures optimal filling of the cavities by the plastic material, which then allows to obtain a hook retainer, for example, having good snagging performance with a counterpart to loops and / or a counterpart with hooks .

The inner face of the molding strip and / or the molding face of the molding support may have a maximum roughness height Rz greater than or equal to 1 μm, preferably greater than or equal to 3 μm and less than or equal to 50 μm. pm.

The network of passages is formed by the roughness of the inner face of the molding strip and / or by the roughness of the molding face of the molding medium. This roughness makes it possible to form the vent allowing air to be evacuated from the cavities into which the plastic material is injected. However, this roughness makes it possible to control the amount of plastic material that can exit the cavity through the inner face of the molding strip.

This roughness can be obtained by sanding the inner face of the molding strip and / or the molding face of the molding medium with sandpaper, for example with sandpaper of grains between 16 and 400, in particular 240.

This roughness can also be obtained by sandblasting the inner face of the molding strip and / or the molding face of the molding support.

This roughness can also be obtained by chemical or laser graining, by knurling or by plasma spraying.

The inner face may have a rim surrounding a opening portion of each cavity and projecting from the inner face, the edges defining between them the network of passages, each rim may have a variable height, so that when the band molding is abutting against the molding support, at least a portion of the flange is not supported against the molding support, so that each cavity is connected to the atmosphere through the network of passages.

As the opening portion of each cavity is surrounded by a rim projecting from the inner face of the molding strip, part of the network of passages is formed by the inner face of the molding strip, between the flanges. Moreover, each edge having a variable height, when the molding strip bears against the molding support, at least a portion of the flange does not bear against the molding support, so that part of the network of passages is also formed by the rim.

It is understood that the height of the rim is measured relative to the outer face of the molding strip and that this height is the maximum height of the rim, measured in a cutting plane parallel to the direction of height, it is that is parallel to the axis of the cavities, and passing through the cavity.

A maximum difference between two heights of the same rim of a cavity may be greater than or equal to 1 μm, preferably greater than or equal to 2 μm, still more preferably greater than or equal to 4 μm and lower or equal to 100 μm, preferably less than or equal to 50 μm.

The rim having a variable height, we compare several maximum heights of the same rim, measured in different sectional planes parallel to the height direction and a maximum difference is determined between all heights, this maximum is greater or equal to 1 μm so as to form an air passage between the cavity and the rest of the network of passages.

Preferably, the maximum difference is greater than or equal to 6 μm, more preferably greater than or equal to 8 μm.

Preferably, the maximum difference is less than or equal to 50 pm.

The network of passages may extend in the longitudinal direction.

It is understood that the passage system allows, when the molding strip bears against the molding support to form a vent for the evacuation of air in the longitudinal direction. It is understood that the passage network may be formed solely of passages strictly parallel to the longitudinal direction.

The network of passages may extend in the transverse direction.

It is understood that the passage network allows, when the molding strip bears against the molding support to form a vent for the evacuation of air in the transverse direction. It will be understood that the passage network may be formed solely of passages strictly parallel to the transverse direction.

The passage network may also be formed of passages extending parallel to the longitudinal direction and parallel to the transverse direction.

Each cavity may define a rod, extending from the outer face to the inner face, and may comprise an end forming a head, extending from the rod towards the inner face of the molding strip.

One can thus form a retaining element having a rod and a head, the head being connected to the base of the ribbon by the rod.

Each cavity of the molding strip may be configured to form a preform of a retaining element.

The preform can then be deformed by known means to form a retaining element.

The molding support may be a molding roll.

[0036] Thus, one of the driving rolls of the molding strip is used as a molding support.

The molding strip may comprise between 10 and 500 cavities / cm ^.

In the height direction, each cavity may have a height greater than or equal to 5 μm, preferably greater than or equal to 20 μm, even more preferably greater than or equal to 100 μm and less than or equal to 5000 μm, preferably less than or equal to 800 μm, still more preferably less than or equal to 500 μm.

When the cavities are not surrounded by a flange, the height of the cavity is measured between the inner and outer faces of the molding strip, for example with respect to two median surfaces defining each face.

When the cavities are surrounded by a flange, the height of the cavity is measured from the outer face of the molding strip and relative to the highest point of the rim measured in a parallel cutting plane to the direction height, that is to say parallel to the axis of the cavities, and passing through the cavity.

The molding strip may comprise a nickel-based material.

Nickel allows in particular to form the continuous endless molding strip or closed on itself in one piece while nickel. The molding strip therefore has no material discontinuity and therefore junction may give rise to fragility of the molding strip. Indeed, if the molding strip is welded on itself, the weld zone is a zone of weakness of the molding strip.

The term "nickel-based material" means materials whose mass content of nickel is predominant. It is understood that nickel is the element whose mass content in the material is the highest. The nickel-based material is, for example, a nickel-based metal alloy having a mass content of at least 40% nickel, preferably at least 60% nickel, still more preferably at least 80% nickel. nickel.

The molding strip may also be made of nickel-plated steel, that is to say that the molding strip is made from a steel strip in which the cavities are perforated and then this strip of The steel is coated with several layers of nickel, for example by electrolysis.

This molding strip made of nickel-plated steel comprises between 5 and 20% by weight of nickel.

The molding strip can be obtained by an additive manufacturing process, for example by chemical or electrochemical deposition, laser sintering of powder, lithography, electroplating, electroforming, etc.

The molding strip may have, in the longitudinal direction, a length of between 0.5 and 5 m.

The molding strip may have, in the transverse direction, a width of between 5 and 3000 mm.

Each cavity may have rotational symmetry around an axis parallel to the height direction.

Thus, a retaining element or a preform having a symmetry of rotation about an axis perpendicular to the base of the ribbon is formed. It is understood that during demolding of the tape, the retaining elements or the preforms can be deformed plastically and not have the symmetry of rotation after demolding.

A portion of the network of passages surrounding at least one of the cavities may have a substantially hexagonal shape.

This hexagonal shape allows to arrange the cavities relative to each other in "honeycomb" or staggered. This arrangement of the cavities makes it possible to achieve a dense arrangement of the retaining elements.

A maximum difference between the height of at least one of the flanges and a height of an adjacent passage of said rim may be less than or equal to 100 .mu.m.

Preferably, a maximum difference between the height of at least one of the flanges and a height of an adjacent passage of said rim may be less than or equal to 75 μm, more preferably less than or equal to 50 μm.

The height of the passage is measured from the outer face of the molding strip, the point having the minimum height of passage when the passage height is measured in different sectional planes parallel to the height direction.

BRIEF DESCRIPTION OF THE DRAWINGS Other characteristics and advantages of the invention will emerge from the following description of embodiments of the invention, given by way of non-limiting examples, with reference to the appended figures, in which: Figure 1 is a schematic sectional view of a molding apparatus for forming a retainer; - Figure 2 is a schematic sectional view of another molding apparatus for forming a retainer; FIG. 3 is a schematic view of the internal face of a molding strip according to a first embodiment of the molding strip; FIG. 4A is a sectional view of the molding strip centered on the cavity in the section plane IV-IV of FIG. 3; - Figure 4B is a sectional view of the molding strip centered on the cavity in the section plane IV-IV of Figure 3, the molding strip being in abutment against the molding support; - Figure 5 is a schematic view of the inner face of a molding strip according to a second embodiment of the molding strip; - Figure 6A is a partial sectional view and in perspective of the molding strip along the plane VI-VI of Figure 5; - Figure 6B is a sectional view of the molding strip centered on the cavity in the section plane VI-VI of Figure 5, the molding strip being in abutment against the molding support; FIG. 7A is a partial view in section and in perspective of the molding strip along the plane VII-VII of FIG. 5; - Figure 7B a sectional view of the molding strip centered on the cavity in the section plane VII-VII of Figure 5, the molding strip being in abutment against the molding support; - Figure 8 is a partial sectional view of a cavity according to another embodiment of the molding strip, the molding strip being in abutment against the molding support; - Figure 9 is a sectional view of another embodiment of the wetting support, the molding strip being in abutment against the molding support.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 represents a schematic sectional view of a molding apparatus 10 for the formation of a retaining device. The molding apparatus 10 comprises a molding strip 12 closed on itself and having an inner face 14, an outer face 16, a plurality of through cavities 18 extending from the outer face 16 to the inner face 14.

The molding strip 12 is stretched on rotational drive means of the molding strip 12, for example two rotary drive rollers 20, 22. One of the rotational drive rollers 20 of the strip molding 12 can act as molding support 24.

The molding support 24 has a molding face 26 intended to bear against the inner face 14 of the molding strip 12. The inner face 14 of the molding strip 12 bears against the drive rollers in rotation 20 of the molding strip 12.

The molding apparatus 10 also comprises a dispensing device 28 of the plastics material 30 in the cavities 18 of the molding strip 12. In FIG. 1, the dispensing device 28 of a material, for example a material 30, is disposed on the side of the outer face 16 of the molding strip 12, vis-à-vis the molding support 26, that is to say that the plastic material 30 is distributed in the cavities 18 of the molding strip when the inner face 14 of the molding strip 12 bears against the molding face 26 of the molding support 24.

For example, the dispensing device 28 may be an injection head of plastic material. The plastic injection head having an opening whose width in the transverse direction is less than or equal to the width in the transverse direction of the molding strip 12.

In Figure 1, the dispensing device 28 is disposed at a distance from the outer face 16 of the molding strip 12 so as to form an air gap 32 between the molding strip 12 and the dispensing device 28.

During the distribution of the plastic material 30 in the cavities 18 of the molding strip 12, a base 34 is also formed on the outer face 16 of the molding strip 12, so as to form, once removed from the mold, a ribbon 36 having a base 34 on which is formed a plurality of retaining members 38 or a plurality of retainer preforms.

The molding apparatus 10 also comprises a demolding roll 40. The demolding roll 40 may for example be configured so as to separate the base 34 from the ribbon 36 of the molding strip 12 under the effect of the tension. ribbon 36 and its change of direction. The demolding roll 40 may be a suction roll or comprise a rubber coating.

Note that the molding apparatus 10 may also include a device for removing an excess of plastic, such as a doctor blade 42 arranged, in the example of Figure 1, on the side of the inner face. 14 of the molding strip 12 and after the molding support 24, in the running direction of the molding strip 12. It is therefore clear that this blade 42 is disposed after the dispensing device 28.

FIG. 2 is a diagrammatic sectional view of another molding apparatus 10 for forming a retaining device.

In the following, the elements common to the various embodiments are identified by the same reference numerals.

The molding apparatus 10 of FIG. 2 differs from the molding apparatus 10 of FIG. 1 in that, in FIG. 2, the molding support 24 is distinct from the rotating drive rollers 20 of FIG. the molding strip 12.

The longitudinal direction X is defined by the direction of travel of the molding strip 12, the transverse direction Y is perpendicular to the longitudinal direction X and the height direction Z is perpendicular to the longitudinal direction X and to the transverse direction Y. The XY plane defines a plane of the molding strip 12 between two rotating drive rollers 20, 22 of the molding strip.

The molding strip 12 may have, in the longitudinal direction, a length of between 0.5 and 5 meters (m), when the molding strip 12 is cut and extended flat.

The molding strip 12 may have, in the transverse direction, a width of between 5 and 3000 millimeters (mm). The width of the molding strip 12 may be equal, for example, to 50 mm, 100 mm or 200 mm.

The molding strip 12 may also comprise between 10 and 500 cavities per square centimeter (cavities / cm 2). For example, the molding strip 12 may comprise 250 cavities / cm 2.

FIG. 3 is a view of the internal face 14 of a molding strip 12. This molding strip 12 comprises cavities 18 and has a maximum height of roughness Rz of 3.23 micrometers (μm), measured according to the standards. ISO 4287 and ISO 4288. This roughness has been measured along the profile 44. Furthermore, along the same profile 44, the arithmetic average deviation of the roughness profile Ra is 532.21 nanometers (nm), also measured according to the standards. ISO 4287 and ISO 4288. This roughness is obtained by sanding the inner face 14 of the molding strip 12 with sandpaper, for example sandpaper 240 grains. The sanding of the inner face 14 creates polishing streaks forming a network of passages 46 on the inner face 14 of the molding strip 12.

In FIG. 3, each cavity 18 has symmetry of rotation about an axis C parallel to the direction of height Z.

In Figure 3, it can be seen that the cavities 18 are aligned in the longitudinal direction X and form a plurality of rows in the longitudinal direction X. In the embodiment of Figure 3, the cavities 18 of a row are spaced apart from each other by a pitch PI, the pitch PI being measured between two axes C of two cavities 18 immediately adjacent of the same row. Two immediately adjacent rows are spaced from one another by a pitch P2, the pitch P2 being measured in the transverse direction, and the cavities of the two rows are offset from each other in the longitudinal direction of a half step PI, that is to say a pitch PI divided by 2, also noted Pl / 2. This offset value is in no way limiting. In the example of FIG. 3, the pitch PI is strictly greater than the pitch P2.

FIG. 4A represents a partial sectional view of the molding strip 12 centered on the cavity 18 in the section plane IV-IV of FIG. 3. This section plane IV-IV is parallel to the ZY plane and comprises the axis C of the cavity 18. The molding strip 12 has an outer face 16 and an inner face 14. The inner face 14 has a roughness as defined above. The height H1 of the cavity 18, measured in the direction of height Z, is measured with respect to two median surfaces defining each face, in this case between the outer face 14 of the membrane and an imaginary surface 48 embodied in FIG. 4A by a median plane of the inner face 14.

In the direction of height Z, each cavity 18 has a height H1 greater than or equal to 5 μm, preferably greater than or equal to 20 μm, even more preferably greater than or equal to 100 μm and less than or equal to 5000 μm. pm, preferably less than or equal to 800 μm, still more preferably less than or equal to 500 μm.

The cavity 18 has a first portion 18A defining a rod of the retaining element 38 and comprises a second portion 18B, forming an end of the cavity 18, extending from the rod towards the inner face 14 of the the molding strip 12 and forming a head of the retaining element 38 (or preform). The first part 18A defining the rod may be of cylindrical or frustoconical shape. For example, the first portion 18A may have a diameter that decreases starting from the outer face 16 and moving towards the inner face 14. The second portion 18B forming the head typically extends radially or transversely with respect to a parallel axis to that of the stem, that is to say parallel to the direction of height. In particular, the diameter of the head widens by moving from the portion 18A to the inner face 14 of the molding strip 12. More particularly, the head has a substantially frustoconical shape. Alternatively, one could consider forming a head having a hexahedral shape. Alternatively, it could also be envisaged that the cavity has at least a part a hyperboloidal shape of rotation or revolution.

The roughness of the inner face 14 of the molding strip 12 forms the network of passages 46, the passage network 46 forming vent 50 and connecting the cavities 18 between them when the molding strip 12 bears against the support molding 24, that is to say when the internal face 14 of the molding strip 12 bears against the molding face 26 of the molding support 24, as shown in Figure 4B.

Figure 5 is a view of the inner face 14 of a molding strip 12 according to another embodiment of the molding strip 12. This molding strip 12 has cavities 18. As in the embodiment of FIG. 3, it can be seen in FIG. 5 that the cavities 18 are aligned in the longitudinal direction X and form a plurality of rows in the longitudinal direction X. In the embodiment of FIG. 5, the cavities 18 of a row are spaced apart from each other by a pitch PI, the pitch PI being measured between two axes C of two adjacent cavities 18 of the same row. Two immediately adjacent rows are spaced from one another by a pitch P2, the pitch P2 being measured in the transverse direction, and the cavities of the two rows are offset from each other in the longitudinal direction of a half step PI, that is to say a pitch PI divided by 2, also noted Pl / 2. Although identified by the same reference numerals, it is understood that the steps PI and P2 may vary between the embodiment of FIG. 3 and the embodiment of FIG. 5. Thus, in the example of FIG. the pitch PI is strictly greater than the pitch P2.

It will be noted that the network of passages 46 formed between the flanges 52 comprises a portion 64 of the network of passages 46 surrounding a cavity 18 which has a substantially hexagonal shape. More particularly, it is the bottom of the network of passages 46 surrounding a cavity 18 which has this substantially hexagonal shape.

In FIG. 5, the inner face 14 of the molding strip 12 has a rim 52 surrounding a through portion of each cavity 18 and projecting from the internal face 14 of the molding strip 12.

In Figure 5, each cavity 18 has a symmetry of rotation about an axis C parallel to the height direction Z. However, the flange 52 may not have rotational symmetry.

Thus, as the flange 52 protruding from the inner face 14 of the molding strip 12, part of the network of passages 46 is formed by the inner face 14 of the molding strip 12, between the flanges 52. By elsewhere, each flange 52 having a variable height HR1, HR2, HR3, HR4, when the molding strip 12 bears against the molding support 24, at least a part of the flange 52 does not rest against the support of molding 24, so that part of the network of passages 46 is also formed by a portion of the flange 52.

As shown in Figures 6A, 6B, 7A and 7B, each flange 52 has a variable height HR1, HR2, HR3, HR4. These heights are measured relative to the outer face 16 of the molding strip 12. Moreover, this height HR1, HR2, HR3, HR4 is the maximum height of the flange 52, measured in a cutting plane parallel to the direction of height Z, that is to say parallel to the axis C of the cavities 18, and passing through the cavity 18. Preferably, the cutting plane comprises the axis C. Indeed, in the plane of section, in view in section, the flange 52 has a maximum height.

In the direction of height Z, each cavity 18 has at least one height HR1, HR2, HR3 or HR4 greater than or equal to 5 μm, preferably greater than or equal to 20 μm, even more preferably greater than or equal to 100 μm. pm and less than or equal to 5000 pm, preferably less than or equal to 800 pm, still more preferably less than or equal to 500 pm.

In the embodiment of FIG. 5, the flange 52 has two maxima 54, 56 and two minima 58, 60, the two maxima 54, 56 being separated by a minimum, and the two minima 58, 60 being separated by one maxima. Thus, when the rim 52 is traversed along the line of maximum heights 62, that is to say the succession of maximum heights of the profile measured in a sectional plane of the cavity 18, a first Maxima 54, we then go through a first minima 58 before moving to a second maxima 56 and then second minimum 60 to finally return to the first maxima 54.

In the example of FIGS. 5, 6A, 6B, 7A and 7B, the maxima 54, 56 respectively correspond to the heights HR1 and HR2 and the minima 58, 60 respectively correspond to the heights HR3 and HR4.

In the example of FIGS. 5, 6A, 6B, 7A and 7B, the height HR1 of the first maxima 54 is different from the height HR2 of the second maxima 56. Likewise, the height HR3 of the first minimum 58 is different from the height HR4 of the second minimum 60.

For example, a maximum difference between two heights of the same rim 52 of a cavity 12 may be greater than or equal to 1 μm, preferably greater than or equal to 2 μm, and even more preferably greater than or equal to 4 μm and less than or equal to 100 μm, preferably less than or equal to 50 μm. For example, if it is considered that HR1 is greater than HR2 and HR3 is greater than HR4, the maximum difference is measured between HR1 and HR4 and is for example equal to 14 pm.

Thus, the flange 52 having a variable height, several of the maximum heights of the same flange 52 are compared, that is to say the maximum heights of the rim 52 measured in different cutting planes parallel to the direction of the rim. height, in other words, the heights of the flange 52 taken along the line of maximum heights 62. A maximum difference is determined between all the heights, this maximum is for example greater than or equal to 1 μm, so as to form a passage of air between the cavity 18 and the remainder of the network of passages 46.

It will also be noted that a maximum difference between the height of at least one of the flanges 52 and a height HP of an adjacent passage 46 of said flange 52 is less than or equal to 100 μm, for example equal to 35 μm. .

It can be seen that the flange 52 comprises at the level of the maxima 54 a plate 66. In FIG. 5, the plate 66 is of substantially oblong shape and has a dimension along the longitudinal direction X of approximately 150 μm and a dimension according to the transverse direction of about 45 pm.

During the use of the molding strip 12, the dimensions of these trays 66 tend to increase following the frictional wear of the molding strip 12 against the molding support 24. Thus, on a new molding strip 12, these trays 66 may not be present or be present on one of the maxima flange 52. Then, as the repeated contacts of the molding strip 12 with the molding support 24 and / or with the rotational drive rollers 20, 22 of the molding strip 12, these trays 66 may be present on all the maxima of the flanges 52 and their dimensions may vary from one flange to the other and during time.

FIG. 8 shows a partial view in section and in perspective of a cavity 18 according to another embodiment of the molding strip 12, the molding strip 12 being in abutment against the molding support 24.

In the example of FIG. 8, the flange 52 which surrounds the cavity 18 and projects from the internal face 14 of the molding strip 12 has a line of maximum heights 62 comprising a succession of maxima and minima, of so that when the molding strip 12 bears against the molding support 24, the cavity 18 is connected with the atmosphere and with the other cavities via the network of passages 46 forming a vent 50.

FIG. 8 may also represent a molding strip 12 whose flange 52 which surrounds the cavity 18 and projects from the internal face 14 of the molding strip 12 has a line of maximum heights 62 that is substantially constant, that is that is, the HR heights measured from the outer face 16 are substantially equal, and have a maximum roughness height Rz greater than or equal to 1 μm, preferably greater than or equal to 3 μm and less than or equal to 50 μm. .

FIG. 9 represents an embodiment of the molding apparatus 10 in which the molding support 24 has a maximum height of roughness Rz greater than or equal to 1 μm, preferably greater than or equal to 3 μm and lower or equal to 50 pm.

In the embodiment of Figure 9, the molding strip 12 does not have a flange. However, it could be envisaged to combine the molding support 24 of FIG. 9 with any of the embodiments of the molding strip presented above.

Thus, the inner face 14 of the molding strip 12 could also have a maximum roughness height Rz greater than or equal to 1 μm, preferably greater than or equal to 3 μm and less than or equal to 50 μm and / or molding strip 12 could have flanges 52 surrounding each cavity 18.

Although the present description has been described with reference to a specific embodiment, it is obvious that various modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In addition, individual features of the various embodiments mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense. For example, the molding apparatus 10 of FIGS. 1 and 2 comprises two rotational drive rollers 20 of the molding strip 12, it could include three of them. It is understood that the number of rolls and their arrangement is not limiting. Their number and their arrangement may vary in order to adapt to the length of the molding strip 12 and / or to the different configurations of the stations of the molding apparatus 10. Moreover, the pitch PI may be equal to pitch P2, the pitch PI may be strictly less than the pitch P2 when a flange surrounds each cavity and vice versa, when the internal face 14 of the molding strip 12 does not have a flange surrounding the cavities 18, the pitch PI may be strictly greater than the pitch P2. It is also conceivable that two rows, taken in the longitudinal direction, immediately adjacent to each other are offset from one another in the longitudinal direction by a step different from a half pitch PI. In the example of FIGS. 5, 6A, 6B, 7A and 7B, the flange 52 has two maxima and two minima. This example is not limiting.

It will also be noted that the figures are not scaled reproductions. Thus, for a better understanding, some details have voluntarily been enlarged in order to be represented.

The molding strip is, according to one embodiment of nickel and comprises a nickel content greater than 90%. One could consider, also using copper strips, brass, or metal alloys. On the other hand, one could also consider using only steel molding strips that are perforated. It could further be envisaged that the molding strip is made of an organic material which may or may not be reinforced, for example a rubber-based molding strip or an epoxy carbon molding strip, or a woven or knitted metal textile carpet.

The hook retainer is here formed by a plastic material. Plastic material is a thermoplastic material, more particularly a polyolefin material based on homopolymer or copolymer.

By way of example, the list of plastics material: LLDPE (Linear Low Density PolyEthylene or Low Density Linear Polyethylene), LDPE (Low Density PolyEthylene or Low Density Polyethylene), m-PE (Metallocene Polyethylene), HDPE (High Density PolyEthylene or High Density Polyethylene), EVA (Ethylene Vinyl Acetate) and PP (PolyPropylene), comprising a monomodal or multimodal (e.g., bimodal) molecular weight distribution, particularly a composition comprising LLDPE and a plastomer, especially a polyethylene base plastomer. Polyamide (PA), polyacetic acid (PLA), polyhydroxyalkanoates (PHA), PVOH, PBS could also be used.

Claims (17)

REVENDICATONS A molding apparatus (10) for forming a retaining device, the molding apparatus (10) comprising a molding strip (12) and a molding support (24), the molding strip (12) having an inner face (14), an outer face (16), a plurality of through cavities (18) extending from the outer face (16) to the inner face (14), the molding strip (12) is extending in a longitudinal direction (X) and having a transverse direction (Y) perpendicular to the longitudinal direction (X) and a height direction (Z) perpendicular to the longitudinal direction (X) and the transverse direction (Y) ), the inner face (14) being configured to bear against a molding face (26) of the molding support (24), in which the inner face (14) of the molding strip (12) and / or the molding face (26) of the molding support (24) comprises a network of passages (46), the network of passages (46) forming a vent (50) and connecting the cavities (18). ) between them when the molding strip (12) bears against the molding support (24). The molding apparatus (10) according to claim 1, wherein the internal face (14) of the molding strip and / or the molding face (26) of the molding support (24) has a maximum height of roughness Rz greater than or equal to 1 μm, preferably greater than or equal to 3 μm and less than or equal to 50 μm. Molding apparatus (10) according to claim 1 or 2, wherein the inner face (14) has a flange (52) surrounding a through portion of each cavity (18) and projecting from the inner face (14), the flanges (52) defining between them the network of passages (46), each flange (52) having a variable height (HR1, HR2, HR3, HR4), so that when the molding strip (12) is supported against the molding support (24), at least a portion of the flange (52) does not bear against the molding support (24), so that each cavity (18) is connected to the atmosphere by the intermediate of the network of passages (46). The molding apparatus (10) according to claim 3, wherein a maximum difference between two heights of a same rim (52) of a cavity (18) is greater than or equal to 1 μm, preferably greater than or equal to at 2 μητι, still more preferably greater than or equal to 4 μm and less than or equal to 100 μm, preferably less than or equal to 50 μm. 5. Molding apparatus (10) according to any one of claims 1 to 4, wherein the network of passages (46) extends in the longitudinal direction (X). The molding apparatus (10) according to any one of claims 1 to 5, wherein the network of passages (46) extends in the transverse direction (Y). The molding apparatus (10) according to any one of claims 1 to 6, wherein each cavity (18) defines a rod, extending from the outer face (16) to the inner face (14), and comprises a head-forming end extending from the shank to the inner face (14) of the molding strip (12). The molding apparatus (10) according to any one of claims 1 to 7, wherein each cavity (18) of the molding strip (12) is configured to form a preform of a retaining member (38). The molding apparatus (10) according to any one of claims 1 to 8, wherein the molding support (24) is a molding roll (20, 22). The molding apparatus (10) according to any one of claims 1 to 9, wherein the molding strip (12) comprises between 10 and 500 cavities / cm 2. The molding apparatus (10) according to any one of claims 1 to 10, wherein, in the height direction (Z), each cavity (18) has a height greater than or equal to 5 μm, preferably greater than or equal to 5 μm. equal to 20 pm, still more preferably greater than or equal to 100 pm and less than or equal to 5000 pm, preferably less than or equal to 800 pm, still more preferably less than or equal to 500 pm. The molding apparatus (10) according to any one of claims 1 to 11, wherein the molding strip (12) comprises a nickel-based material. The molding apparatus (10) according to any one of claims 1 to 12, wherein the molding strip (12) has. in the longitudinal direction (X), a length of between 0.5 and 5 m. The molding apparatus (10) according to any one of claims 1 to 13, wherein the molding strip (12) has a width in the transverse direction (Y) of between 5 and 3000 mm. 15. Molding apparatus (10) according to any one of claims 1 to 14, wherein each cavity (18) has a symmetry of rotation about an axis (C) parallel to the direction of height. The molding apparatus (10) according to any one of claims 1 to 15 taken in combination with claim 3, wherein a portion (64) of the network of passages (46) surrounding at least one of the cavities (18) presents a substantially hexagonal shape. The molding apparatus (10) according to any one of claims 1 to 16 taken in combination with claim 3, wherein a maximum of difference between the height of at least one of the flanges (52) and a height of an adjacent passage (46) of said rim (52) is less than or equal to 100 μm.