FR2816543A1 - Molded plastic component with covering layer for e.g. motor vehicle interior trim, has at least part of covering layer edge folded over in mold for fixing in component - Google Patents

Abstract

A molded plastic component is made by cutting out a covering layer (6), to the required size plus a projecting perforated edge all round. The projecting edge (10) is folded over before insertion in the cavity of a mold (20), and held in position by a support (36). The cavity is then filled with molten plastic so that it covers the back of the covering layer and the folded edge fixing it in place. A molded plastic component is made by cutting out a covering layer (6), to the required size plus a projecting perforated edge all round. At least part of the projecting edge (10) is folded over before inserting the layer in the cavity of a mold (20), and the folded edge can be held in position by an adhesive or supports (36) projecting from the second part (26) of the mold. The cavity is then filled with molten plastic by injection so that it covers the back of the covering layer and the folded edge, passing through the perforation holes and fixing it in place as the plastic hardens.

Description

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 The present invention relates to a method of manufacturing a plastic part provided with a coating.

 It applies in particular to the methods of manufacturing coated parts for the interior of the passenger compartment of motor vehicles.

 There are known in the state of the art methods of manufacturing a plastic part coated with a plastic or fabric sheet.

 The manufacture of such parts is usually carried out by overmolding of the plastic material on one side of the sheet.

 The overmolding methods of the prior art include the following steps: - a covering blank is cut which has a tightening edge which goes all around; - The blank is clamped by its clamping edge between two half-molds and plastic material is injected on one side of the tight blank; - After hardening of the plastic, the coated part is removed from the mold, the clamping edge not being covered with plastic.

 The part is finished by folding and gluing the clamping edge to the rear surface of the plastic part and / or by cutting the clamping edge.

 These known methods have several drawbacks: the step of cutting the edge is an additional operation which is costly; - the outer edge of the covering is not covered with plastic. At this location, the coating is likely to come off the plastic. In addition, in the case where the covering is a fabric, the edge tends to peel off, forming fringes;

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 the clamping edge must have a sufficient width to allow good tightening of the blank between the mold halves. As a result, part of the coating material is lost as a cutting scrap.

 The invention aims to overcome these drawbacks.

 To this end, the subject of the invention is a manufacturing process of the aforementioned type, characterized in that it comprises the following steps: - a coating blank is cut; - At least part of the edge of the blank is folded back on itself, forming the outline of at least part of the periphery of the part; - The blank is placed in a first part of a mold, the folded edge being maintained in the folded state; the mold is closed by applying a second mold part to the first part of the mold, and there is left between, on the one hand, the surface defined by said folded edge and the surface of the blank on which said edge is folded, and , on the other hand, said second part of the mold, a molding cavity; - The plastic injection molding cavity is filled on the side of the side of the blank on which said edge is folded; - the plastic is allowed to harden, the folded edge being immobilized relative to the rest of the blank by the hardened plastic; and - the finished part is removed from the mold.

 According to particular embodiments of the invention, it may include one or more of the following characteristics: - when the mold is closed, the only outer zone of the folded edge is clamped between said first and second parts of the mold ; - the folded edge goes all around the blank;

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 - The edge is kept in the folded state by holding means; - The holding means comprise glue; the folded edge has at least one non-rectilinear part and the holding means comprise a holding member fixed to the folded surface of the edge, disposed between the folded edge and the main area of the blank, at least on either side of the non-rectilinear part; - The holding member is a fixed frame, in particular stapled, at the folded edge; the holding means comprise extendable members of said second part of the mold which push the folded edge against the rear surface of the blank, forming a part of the mold cavity; - Cut-out openings are cut in the blank area which corresponds to the folded edge; and a space is left between the main area of the blank and the edge of the folded edge facing the center of the main area so that the plastic material completely covers the edge of the folded edge.

 The invention further relates to a part comprising a main body of plastic material provided with a coating which extends on one side of the part in the region of the edge of the main body and on at least one adjacent part thereof. ci, characterized in that in the area of the edge of the main body, the edge of the covering is folded over and the edge fold forms a line defining the line of the edge of the part, projecting from the edge of the main body, and in this that the folded edge is fixed on the main body and is partially covered by the plastic of this body.

 The plastic part can have one or more of the following characteristics: - the plastic of the main body is

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 between the interior area of the folded edge and the main part of the covering; and - the part is a door for a storage compartment for a motor vehicle.

 The invention further relates to a molding device for implementing the manufacturing process, of the type comprising at least first and second mold parts, characterized in that said second part of the mold comprises extensible members, in the zone corresponding to the folded edge of the part, movable between a retracted position and an advanced position in which they are applied against the folded edge of the covering.

 The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to the accompanying drawings in which: - Figure 1 is a sectional view of a first embodiment a plastic part according to the invention; - Figure 2A is a schematic top view of a coating blank according to the invention; - Figure 2B is a sectional view along the line IIB-IIB of Figure 2A; - Figure 3A is a top view of the blank of Figure 2A with the edges folded; - Figure 3B is a sectional view along the line IIIB-IIIB of Figure 3A; - Figures 4A to 4D are sectional views of a first embodiment of a mold according to the invention in different stages of molding; - Figure 5 is a sectional view of a second embodiment of a plastic part according to the invention;

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ci. - Figure 6A is a top view of a blank for a part according to the second embodiment of the invention; - Figure 6B is a sectional view along the line VIB-VIB of Figure 6A; - Figure 7A is a top view of the blank of Figure 6A with the edges folded; - Figure 7B is a sectional view along the line VIIB-VIIB of Figure 7A; and - Figures 8A to 8C are sectional views of a second embodiment of a mold for implementing the method according to the invention at different stages of it-

this.

 In Figure 1, there is shown a plastic part 2 according to the invention.

 In what follows, the expression front will designate the direction directed towards the user in the assembled state, that is to say the visible part of the part, while rear will designate the opposite direction.

 The plastic part 2 is for example a piece of equipment for a passenger compartment of a motor vehicle, such as a storage compartment door. The part 2 is substantially flat and of generally rectangular shape. It comprises a main body 4 of injected plastic, for example polyethylene.

 The front surface of the part 2 is provided with a coating 6, for example a plastic or fabric sheet. It should be noted that the thickness of the coating 6 is shown in the figures in an exaggerated manner with respect to the thickness of the main body 4 in order to increase the clarity of representation.

 The coating 6 comprises a main rectangular area 8 forming the visible surface. It further comprises an edge 10 folded over the rear surface of the zone

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 main 8 by forming the outline of the periphery of the coated part 2. The main body 4 extends substantially over the entire rear surface of the main area 8 of the covering and covers the folded edge 10. The plastic of the main body 4 immobilizes the folded edge 10 relative to the main area 8 and avoids an unfolding of the edge.

 In order to increase the securing effect between the folded edge 10 and the main body 4, the edge 10 has circular securing openings 12. The plastic material extends through these securing openings 12 and is secured to the rear surface of the covering of the main zone 8.

 In FIGS. 2A and 2B, there is shown a blank 14 of coating used for the manufacture of the part 2. The blank 14 is in substantially rectangular shape with corners cut at 45. It comprises a main rectangular area 8A corresponding to the main area 8 of the covering of the part 2, as well as an edge area 10A corresponding to the folded edge 10 of the covering. The securing openings 12 are cut in the edge area 10A.

Alternatively, they may have other shapes, for example an oval shape.

 FIGS. 3A and 3B show the covering blank 14 with the edge 10 folded over the rear surface of the main area 8A.

 To prevent unfolding of the folded edge, it can be glued against the main area 8A of the covering.

 In FIGS. 4A to 4D, a mold 20 has been shown for the manufacture of the coated part 2 of FIG. 1.

 The mold 20 comprises a first lower and fixed half-mold 22 which has a receiving recess 24 for the blank 14 with folded edge (Figures 3A and 3B).

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 The mold 20 further comprises a second vertically movable half-mold 26 (arrow V) and disposed above the first half-mold 22. A molding recess 28 is formed in the surface of the second half-mold 26 facing the first half-mold 22. This molding recess 28 comprises a stepped periphery 30, the lower stage 31 of which forms a clamping part of the folded edge 10. This clamping part 31 is applied only against the external zone of the folded edge 10 of the blank 14 in the closed state of the mold (Figure 4B).

The molding recess 28 further comprises a part forming a molding cavity 32 and is of complementary shape to the main body 4 of the part 2 made of plastic.

 An injection pipe 34 of liquid plastic material is formed in the second half-mold 26 and opens into the central part of the molding cavity 32.

 The second half-mold 26 further comprises drawers 36 for holding the folded edge 10. These drawers 36 are housed in bores 38 formed in the second half-mold 26 and with vertical axes, parallel to the direction of movement of the second half mold 26. The drawers 36 are extendable cylindrical rods between, on the one hand, a retracted position in which their lower ends are flush with the surface of the molding cavity 32, as shown in FIG. 4A and, on the other hand, a holding position in which they protrude from the surface of the mold cavity 32 and are applied against the inner zone of the folded edge 10 of the blank (FIG. 4B).

 The coated plastic part is produced in the following manner.

 First of all, the covering blank 14 is cut (FIGS. 2A, 2B). Then, the edge area 10A is folded over the main area 8A of the blank and the blank 14 with folded edge is obtained (FIG. 3A, 3B), the periphery of which forms the outline of the periphery of the finished part 2.

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 The blank 14 is placed with the folded edge in the receiving recess 24 of the first half-mold 22, with its front surface applied flat against the surface of this recess 24.

 Then, the mold 20 is closed by lowering the second half-mold 26, the outer zone of the folded edge 10 being clamped between the receiving recess 24 of the first half-mold 22 and the clamping part 31 of the second half-mold 26. Then the holding drawers 36 are removed and the interior area of the folded edge 10 is pressed with these against the rear surface of the main area 8A of the blank.

Consequently, a molding cavity 40 is formed between the folded edge 10 as well as the rear surface of the blank 14 and the surface of the molding recess 28 of the second half-mold 26 (FIG. 4B).

 Liquid plastic material 42 is injected through the injection pipe 34 into the molding cavity 40 (FIG. 4C), and the holding drawers 36 are retracted. Then the plastic material 42 is allowed to harden.

 It can be seen that during the hardening of the plastic 42, the folded edge 10 of the covering 6 is immobilized with respect to the rest of the covering by joining the plastic 42 with the covering 6. The securing openings 12, which are also filled with plastic material 42, contribute to this effect.

 Finally, the mold 20 is opened and the part 2 made of finished coated plastic is removed from the mold.

 It can be seen that the coated part 2 can be used without cutting the protruding parts of the coating 6. In addition, there is a very good connection between the coating 6 and the plastic in the edge area 10, so that the risk of The wicking effect is greatly reduced at this location.

 In Figures 5 to 8C there is shown a second embodiment of the invention. In the following

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 only the differences from the first embodiment will be described. Elements similar to the first embodiment bear identical references.

 In Figure 5 is shown a plastic part 2 provided with a coating 6. The folded edge 10 of the coating does not have securing openings.

By cons, a holding frame 50, consisting of four bars 52, is fixed to the folded surface of the edge 10. It is disposed between the folded edge 10 and the main area 8 of the coating.

 In the assembled state, the frame 50 keeps the edge 10 folded back before the plastic of the main body 4 hardens.

 In addition, the folded edge 10 has a width greater than the width of the bars 52 of the frame 50, so that it protrudes from the frame 50 towards the center of the main area.

 The main body 4 extends on either side of the edge 54 of the folded edge 10, that is to say also between this edge and the main part 8 of the covering, which results in good attachment of the folded edge 10 with plastic.

 In FIGS. 6A and 6B, the blank 14 and the frame 50 of the second embodiment of the part 2 are shown.

 The frame 50 is placed on the rear surface of the main area 8A of the blank 14. It has a periphery of shape similar to the periphery of the finished part 2 reduced on each side by the thickness of the coating 6. The bars 52 of the frame 50 are for example made from a net or a sheet of plastic material. Staples 56 are incorporated into these bars and protrude from the rear side thereof.

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 As seen in FIGS. 7A and 7B, the edge 10 of the blank 14 is folded over the frame 50. The rods of the staples 56 are folded over the rear surface of the folded edge 10.

They keep the folded edge 10 in this position.

 It should be noted that the frame 50 must extend along at least one non-rectilinear part of the periphery of the folded edge 10 and must be fixed on the latter in at least two locations situated on either side of this non-straight part to prevent unfolding of the edge 10.

 Additionally, the retaining frame 50 can be glued against the rear surface of the main area 8A of the blank.

 In FIGS. 8A to 8C, a mold 20 can be seen for manufacturing the part 2 according to the second embodiment.

 The receiving recess 24 of the first half-mold 22 has a depth corresponding to the thickness of the main zone 8 of the covering and of the frame 50.

 The second half-mold 26 is made up of five parts, namely four lateral parts 60 and a central part 62. The lateral parts 60 (three of which are visible) are movable in translation horizontally (arrow H, FIG. 8A) between an open position remote from the edge of the receiving recess 24 and a molding position in which they are applied against the central part 62 (FIG. 8B). The lateral parts 60 comprise, on their lower edge facing the receiving recess 24, a clamping part 64 of the only outer zone of the folded edge 10. The central part 62 of the second half-mold 26 can be moved between a raised position d opening (Figure 8A) and a lowered molding position (Figure 8C).

 The plastic part 2 according to the second embodiment is produced in the following manner.

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 First of all, the covering blank 14 is cut and the retaining frame 50 is prefabricated. Then, the retaining frame 50 is placed on the rear surface of the blank 14 (FIG. 6A), the edge 10A of the blank is folded over the staples 56, and these are closed (FIG. 7A).

 Then, the blank 14 is placed with the folded edge in the receiving recess 24 of the first half-mold 22, the folded edge 10 being directed upwards (FIG. 8A).

 Firstly, the outer zone of the folded edge 10 is tightened in the mold 20 by displacement of the lateral parts 60 of the second half-mold 26 in their molding position, and, in a second step, the mold 20 is closed completely in lowering the central part 62 of the second half-mold 26 into its molding position.

 Then plastic material 42 is injected into the molding cavity through the injection pipe 34. Then, the plastic material 42 is left to harden, the mold 20 is opened, and the finished part 2 is demolded.

 Like the part of the first embodiment, the finished part 2 can be used without the need to cut a clamping edge. As a result, machinery investments are reduced. In addition, because the plastic material covers the edge of the folded edge, a part according to the invention can be used without lining which hides the edge. As a result, a part and the corresponding mounting operations are saved.

Claims (14)

 CLAIMS 1. Method for manufacturing a plastic part (2) provided with a coating (6), characterized in that it comprises the following steps: - a blank (14) of coating (6) is cut; - At least part of the edge (10A) of the blank (14) is folded back on itself, forming the outline of at least part of the periphery of the part (2); - The blank (14) is placed in a first part (22) of a mold (20), the folded edge (10) being kept in the folded state; - the mold (20) is closed by applying a second part (26) of the mold to the first part (22) of the mold, and there is left between, on the one hand, the surface defined by said folded edge (10) and the surface of the blank on which said edge is folded, and, on the other hand, said second part (26) of the mold, a molding cavity (32); - The mold cavity (32) is filled by injection of plastic material (42) on the side of the face of the blank (14) on which said edge (10) is folded; - the plastic material (42) is allowed to harden, the folded edge (10) being immobilized relative to the rest of the blank (14) by the hardened plastic material; and - the finished part (2) is removed from the mold.  2. Method according to claim 1, characterized in that when the mold is closed (20), the only outer region of the folded edge (10) is clamped between said first (22) and second (26) parts of the mold.  3. Method according to claim 1 or 2, characterized in that the folded edge (10) goes all around the blank (14).  4. Method according to any one of claims 1 to 3, characterized in that the edge (10) is kept in the folded state by holding means (36; 50). <Desc / Clms Page number 13> 5. Method according to claim 4, characterized in that the holding means comprise glue.  6. Method according to claim 4 or 5, characterized in that the folded edge (10) has at least one non-rectilinear part and the holding means comprise a holding member (50) fixed on the folded surface of the edge, disposed between the folded edge (10) and the main area of the blank (14), at least on either side of the non-rectilinear part.  7. Method according to claim 6, characterized in that the holding member is a frame (50) fixed, in particular stapled, to the folded edge (10).  8. Method according to any one of claims 4 to 7, characterized in that the holding means comprise members (36) extendable from said second part (26) of the mold which push the folded edge (10) against the rear surface of the blank (14) by forming a part of the molding cavity (32).  9. Method according to any one of claims 1 to 8, characterized in that the securing openings (12) are cut in the area of the blank (10A) which corresponds to the folded edge.  10. Method according to any one of claims 1 to 9, characterized in that a space is left between the main area of the blank (8A) and the edge (54) of the folded edge facing the center of the area main, so that the plastic material (42) completely covers the edge (54) of the folded edge.  11. Part comprising a main body (4) of plastic material provided with a coating (6) which extends on one side of the part (2) in the area of the edge of the main body (4) and on at least one adjacent part thereof, characterized in that in the region of the edge of the main body (4), the edge (10) of the covering is folded over and the <Desc / Clms Page number 14>  fold of this edge forms a path defining the path of the edge of the part (2), projecting from the edge of the main body (4), and in that the folded edge (10) is fixed to the main body (4) and is partially covered by plastic material from this body.  12. Part according to claim 11, characterized in that plastic material of the main body (4) is located between the interior area of the folded edge (10) and the main part (8) of the coating.  13. Part according to claim 11 or 12, characterized in that the part (2) is a door for a storage compartment of a motor vehicle.  14. Molding device for implementing the manufacturing method according to claim 8 or dependent on claim 8, of the type comprising at least first (22) and second (26) mold parts, characterized in that said second mold part (26) comprises extendable holding members (36) in the zone corresponding to the folded edge (10) of the part, movable between a retracted position (FIG. 4A) and an advanced position (FIG. 4B) in which they 'apply against the folded edge (10) of the covering (6).