FR3066132A1 - METHOD FOR MANUFACTURING A COVER WITH COATING HAVING A VISUAL CHARACTERISTIC - Google Patents

Abstract

The subject of the invention is a method for manufacturing a part provided with a coating (2), comprising in particular the positioning of the coating (2) having in its place visual characteristics (4), in a first part of a mold (20) comprising a second complementary part, this method being remarkable in that it comprises an indexed placement step of the location of the coating (2) on the first part of the mold (20) by the insertion through this coating (2) in the visual characteristics (4), protruding needles (24) positioned in this first part (20), which can slide axially in, then a mold closing step comprising a movement of the second part to the against the coating (2), and the simultaneous retraction of the needles (24) by their sliding in the first part (20).

Description

DESCRIPTION

The present invention relates to a method of manufacturing a part provided with a coating, as well as a mold implementing such a method, and an interior trim panel of a motor vehicle produced with such a method.

This process notably includes the positioning on the lower part of the tooling of a coating having a visual characteristic.

Certain coverings intended for covering panels constituting a support having any shape, in particular interior trim panels for motor vehicles, have on one side visual characteristics having a functional or decorative appearance, such as seam lines, which must be arranged in a precise positioning to obtain the desired functional or decorative characteristics.

These coatings may have a backing disposed on a support. The coating can be synthetic or natural, such as fabrics, synthetic skins or leather skins.

A known method of positioning and maintaining a connection forming a marking produced between two pieces of a covering, for assembling this covering on a seat foam, presented in particular by document US-A1-7134730, comprises the preparation of the connection comprising the insertion of a guide strip between two edges of the two parts each forming a fold.

The guide strip ends down in a pointed shape, protruding below the link. The connection is then inserted into a groove formed on the foam, the point shape of the guide strip being inserted into a slot made at the bottom of the groove so as to maintain this connection in position in the groove.

A problem which arises with this positioning and holding process is that the guide strip remains in place in the connection on the finished product, which is not admissible for certain products.

Another known method for positioning a sewn connection between two pieces of a covering, in a mold for performing on the back of the covering the injection of a foam, presented in particular by document JPH-A-054236, comprises the preparation of the connection comprising the insertion of a guide strip between the two flanges each forming a fold, and the production of a seam sewing the two flanges on this guide strip.

The coating is then deposited on the surface of the mold, by fitting studs formed on this surface in holes made on the edge of the guide strip, in order to position it precisely. The foam is then injected.

After removing the product from the mold, the guide strip with a line along its length formed by a series of close holes is broken along this line in order to eliminate the part of the strip facing outwards from this product. This process also requires leaving part of the guide strip in the coating connection, which is not admissible for certain products.

Another known method of positioning sewn connections between two pieces of a coating in a mold, for performing on the back of the coating the injection of a foam, presented in particular by document JP-A-2988957, comprises the removal of the covering on a frame by adjusting the links sewn on the edge of the blades fixed on this frame. The blades penetrate into the connection between the edges of these pieces, up to the seam.

After injecting the foam, the frame with its blades is removed. However, this process poses problems for certain coatings because it requires at least partial insertion of the blades in the connections, which cannot be done with all types of sewing and connection.

The object of the present invention is in particular to avoid these problems of the prior art.

To this end, it proposes a method of manufacturing a part provided with a coating, this method comprising in particular the positioning of the coating having visual characteristics on its place, in a first part of a mold comprising a second complementary part, this method being remarkable in that it comprises a step of indexed placement of the location of the coating on the first part of the mold by the insertion through this coating in the visual characteristics, of protruding needles positioned in this first part, which can slide axially in, then a step of closing the mold comprising a movement of the second part towards the back of the coating, and the simultaneous retraction of the needles by their sliding in the first part.

An advantage of this manufacturing process is that when the mold is closed, in particular for bonding the reverse side to a part forming a support, or molding foam on this back, the retraction of the guide needles into the form of the first part of the mold, in particular with a repulsion by the shape of the second part which lowers or slides, makes it possible to perfectly position the visual characteristics while not leaving on the back of the covering any part of the guide means formed by needles. In general, the visual characteristics on the coating can be constituted by a seam between parts of this coating, or by any other marking process forming an aesthetic or functional element. In particular, the marking can form a line having any curvature.

The positioning method according to the invention may also include one or more of the following characteristics, which can be combined with one another.

In particular, the process may include, before the step of placing the coating on the first part of the mold, a prior step of bonding a layer of foam on the reverse side of the coating.

The process may also include, before the step of placing the coating on the first part of the mold, a prior step of coating the adhesive on the back of the coating or the layer of foam.

In this case, the method may include a step of placing a support on the second part of the mold before the step of closing the mold.

As a variant, after the mold has been closed, the process may include a step of injecting foam on the back of the coating.

According to one embodiment, the visual characteristics consist of at least one seam line joining two component parts of the coating, and the indexed placement of the coating on the first part of the mold consists in positioning the seam line so that the needles protruding position cross the covering at this seam line between two pieces.

Advantageously, the movement of the second part of the mold mechanically causes a synchronous retraction movement of all of the needles in the first part of the mold.

Advantageously, the needles are moved into the retracted position during the movement of the second part of the mold, against a stress from an elastic system forcing them into the projecting position.

In particular, the indexed placement of the coating on the first part of the mold can consist of inserting at least two distinct groups of protruding needles in at least two seam lines forming visual characteristics.

In addition, before closing the mold, the method may include an additional step of visual control by light radiation from a light source. The subject of the invention is also a mold for manufacturing a part of the surface panel type provided with a coating, comprising two parts which are movable relative to each other, namely a first part and a second part, and intended for the implementation of the method described above, this mold being remarkable in that the first part is configured and equipped to receive the coating with an indexed placement, and in that it comprises positioning means integrating at least one group retractable needles arranged in a line or pattern coinciding with at least one visual characteristic.

Advantageously, the needles are mounted to slide in their respective axial directions and are urged into the projecting position under the effect of an elastic force.

Advantageously, the needles are mounted on elastic systems.

Alternatively, the needles can be fixed on a movable plate mounted on elastic systems.

According to one embodiment, the needles form groups arranged according to the trajectories of seam lines targeted in the final piece.

Alternatively, the mold may include a second part having a horizontal displacement. The invention further relates to a part of the interior trim panel type of a motor vehicle, remarkable in that it is produced with a manufacturing process comprising any of the preceding characteristics. The invention will be better understood and other characteristics and advantages will appear more clearly on reading the description below given by way of example and without limitation, with reference to the appended drawings in which: FIGS. 1, 2 and 3 show in cross section three successive operations for preparing a coating before it is assembled on a support; Figures 4, 5 and 6 show in cross section on a diagram three successive stages of production of a part comprising this coating, with a manufacturing process according to an alternative embodiment of the invention (vertical movement of the movable mold part ); Figures 7, 8 and 9 show a mold for the manufacturing process according to the invention; Figures 10a, 10b and 10c show three successive stages of positioning the coating on the lower part of the mold, according to a variant using a hand tool, and Figure 11 shows an additional positioning control system to check the positioning of the coating in the mold.

Figure 1 shows two pieces of skin cut and sewn together flat with a first seam 4, each edge 6 is then folded upside down and sewn with a second seam 8 parallel to the first, to form a double flap seam.

FIG. 2 shows the bonding of a layer of foam 10 on the back of the pieces of skin intended to form the covering 2.

FIG. 3 presents a gluing of the reverse side of the foam layer 10 of the covering 2, with an automatic coating machine comprising rollers 12 carrying out, during the running of the sewn assembly, a uniform deposit of glue 14 over the entire surface of this layer of foam.

FIG. 4 shows the lower part of a mold 20 comprising on an upper surface the external shape of a part to be produced. The surface of the top comprises a succession of vertical needles 24 which can slide along their axis, arranged along the seam line 4 of the covering.

The bases of the needles 24 are fixed on a movable plate 22 arranged in a free space inside the lower part of the mold 20, which is pressed upwards by springs 26.

An operator deposits the place of the covering 2 on the surface of the top of the lower part 20, by adjusting the needles 24 through this covering, passing between two pieces of skin at the level of the line of the first seam 4.

In this way, the seam lines 4, 8 are adjusted with a precise positioning given by the succession of needles 24, as a function of a decoration to be produced with these seams on the final piece.

It will be noted that the positioning of the seam lines 4, 8 connecting two pieces of skin is also important in order to be able to give the curve to the covering in the space on the finished piece, in order to avoid folds or particular tensions. which would degrade the appearance of the coating.

FIG. 5 shows the descent of an upper part of the mold 30, comprising a bottom surface having received a molded form of plastic material 32, which is complementary to the surface of the top of the lower part 20.

FIG. 6 shows the closing of the mold with a certain pressing of the upper part 30 on the covering 2, which gives a regular bonding of the molded form 32 on the reverse side of the layer of foam placed on the back of the covering 2. end of the descent of the upper part 30, the molded form 32 presses on the upper end of the needles 24, which makes them slide automatically by lowering the movable plate 22 supporting them.

There is obtained in this way an automatic withdrawal of the needles 24 which no longer protrude on the reverse side of the coating 2, the molded shape 32 not being hindered by these needles to come to be pressed entirely on this back.

In a next step, not shown, the upper part of the mold 30 is opened, then the molded form 32 is taken out with its coating 2 uniformly bonded thereto, without finding any trace of the needles 24. The movable plate 22 and the needles 24 then rise automatically under the effect of the springs 26, the mold being ready to be used for the manufacture of new parts.

FIG. 7 shows the lower part of the mold 20 comprising a base plate receiving at each angle a guide 40 comprising a vertical axial drilling. A basic shape 42, arranged in the center of the lower part 20, is surrounded by balusters 44.

Needles 24, aligned along a seam line, have their lower ends fixed on the movable plate 22 disposed above the base plate.

FIG. 8 shows the lower part of the mold 20 having received a counter-form 46 bearing on the balusters 44, representing the external surface of the part to be produced.

The upper ends of the needles 24 pass through the counterform 46 to protrude above. The operator deposits the place of the covering on the counterform 46 by adjusting the needles 24 in the seam line to position this covering.

Figure 9 shows the upper part 30 forming a plate having above the lifting rings 50, and below at each angle a vertical rod 52 which adjusts in the bore of each guide 40 of the lower part 20, to allow the vertical sliding of this upper part.

The surface of the underside of the upper part 30 has a face receiving the molded shape 32 which is applied to the back of the coating 2 having received the adhesive. During the descent of the upper part 30, the needles 24 and the movable plate 22 descend.

A press applies a significant force to the upper part 30, in order to achieve complete bonding of the molded form 32 on the coating 2. In general the mobile part or second part of the mold, called in the example above upper part 30, has a substantially vertical movement or displacement. However, it may alternatively have a movement comprising any inclination, which may in particular be a substantially horizontal displacement. The mobile part can also alternatively carry out different movements, such as a pivoting. Finally, it can also be provided that the two mold parts are movable, this variant being nevertheless more complex.

FIG. 10a shows a positioning of the covering 2 with a manual tool, comprising a handle 60 comprising a vertical fine lower rod 62 that the operator introduces into the seam 4 between two pieces of skin of the covering 2.

FIG. 10b shows a following operation for lowering the coating 2, the operator guiding the handle 60 to adjust its lower rod 62 in an axial bore of a needle 24.

Once each lower rod 62 has been adjusted in the axial bore of the corresponding needle 24, the operator presses the covering 2 downwards to return these needles to the seam 4. In this way, the lower rods 62 constitute guides which allow to easily lower the coating 2 onto the needles 24.

FIG. 10c shows a following operation where the operator removes the handle 60. The covering 2 is completely positioned on the lower part 20.

FIG. 11 shows in addition a visual control system by light radiation, using in particular laser radiation, which comprises a light source 70 arranged above projecting on the back of the coating 2, positioned on the lower part of the mold 20, a light trace corresponding to particular points of this coating.

In particular, the light tracing can follow the seam line 4, the operator can thus directly check the correct positioning of this seam line. This control method can use in particular the method presented in document FR-A1-2932715. In general, the positioning of the coating according to the invention makes it possible to produce parts receiving on the back a support by any type of process, comprising in particular an overmolding by injection of foam in a closed mold, or the fixing of support by thermocompression.

The path of the seams can have any shape. The needles 24 can also be used to position any type of visual characteristic on the covering, other than seams.

Of course, the invention is not limited to the embodiments described and shown in the accompanying drawings. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without thereby departing from the scope of protection of the invention.

Claims (18)

-9- CLAIMS 1. A method of manufacturing a part provided with a coating (2), this method comprising in particular the positioning of the coating (2) having visual characteristics (4) in its place, in a first part of a mold (20 ) comprising a second complementary part 5 (30), a method characterized in that it includes a step of indexed placement of the location of the coating (2) on the first part of the mold (20) by insertion through this coating (2) in the visual characteristics (4), projecting needles (24) positioned in 3 this first part (20), which can slide axially therein, then a step of closing the mold comprising a movement of the second part (30 ) towards the back of the covering (2), and the simultaneous retraction of the needles (24) by their sliding in the first part (20). 2. Method according to claim 1, characterized in that it comprises before the step of placing the coating (2) on the first part of the mold (20), a prior step of bonding a layer of foam (10) on the back of the covering (2). 3. Method according to claim 1 or 2, characterized in that it 3 comprises before the step of placing the coating (2) on the first part of the mold (20), a prior step of coating the adhesive (14) on the back of the covering (2) or the foam layer (10). 4. Method according to claim 3, characterized in that it comprises a step of placing a support (32) on the second part 5 of the mold (30) before the step of closing the mold. 5. Method according to any one of claims 1 to 3, characterized in that after closing the mold it comprises a step of injecting foam on the reverse side of the coating (2). 6. Method according to any one of the preceding claims 3, characterized in that the visual characteristics (4) consist of at least one seam line joining two constituent parts of the covering (2), and in that the indexed placement of the covering (2) on the first part of the mold (20) consists in positioning the seam line so that the needles (24) in the projecting position - 10- pass through the covering (2) at this seam line between two pieces . 7. Method according to any one of the preceding claims, characterized in that the movement of the second part of the mold (30) mechanically causes a synchronous retraction movement of the set of needles (24) in the first part of the mold (20). 8. Method according to any one of the preceding claims, characterized in that the needles (24) are moved into 3 retracted position during the movement of the second part of the mold (30), against a solicitation of an elastic system (26) forcing them into a projecting position. 9. Method according to any one of the preceding claims, characterized in that the indexed placement of the coating (2) on the first part of the mold (20) consists in inserting at least two distinct groups of projecting needles (24) into at least two seam lines forming visual features (4). 10. Method according to any one of the preceding claims, characterized in that before closing the mold it comprises an additional step of visual control by light radiation from a light source (70). 11. Mold for manufacturing a part of the surface panel type provided with a coating (2), comprising two parts movable with respect to each other, namely a first part (20) and a second part ( 30), and intended for implementing the method according to any one of the preceding claims, mold characterized in that the first part (20) is configured and equipped to receive the coating (2) with an indexed placement, and comprises positioning means integrating at least one group of retractable needles (24) arranged in a line or a pattern coinciding with at least one visual characteristic (4). 12. Mold according to claim 11, characterized in that the needles (24) are slidably mounted in their respective axial directions and are biased in the projecting position under the effect of an elastic force. 13. Mold according to claim 12, characterized in that the needles (24) are mounted on elastic systems (26). - 11 - 14. Mold according to claim 12, characterized in that the needles (24) are fixed on a movable plate (22) mounted on elastic systems (26). 15. Mold according to any one of claims 11 to 14, 5 characterized in that the needles (24) form groups arranged according to the trajectories of seam lines referred to in the final part. 16. Mold according to any one of claims 11 to 15, characterized in that it comprises a second part (30) having a substantially vertical displacement. 17. Mold according to any one of claims 11 to 15, characterized in that it comprises a second part (30) having a substantially horizontal displacement. 18. Part of the interior trim panel type of a motor vehicle, characterized in that it is produced with a manufacturing process according to any one of claims 1 to 10.