"MOULDING METHOD FOR THE MOULDING OF A COMPONENT PROVIDED WITH SNAP-FIT ELEMENTS AND COMPONENT THEREOF"

[001] The present invention relates to a moulding method for the moulding of a component provided with snap-fit elements and component thereof made using said moulding method.

[002] The production of moulded components, such as panels, lids, inserts provided with snap-fit elements or clips able to permit the assembly of the component to a relative support, is known of in the art. For instance, panels provided with elastic clips on the inner side destined to face the relative support, enabling the snap-fit of said panel, are made. Preferably the clips are elastic so as to also allow the dismantling of the component in the event of replacement or servicing. [003] Components of this type are, for instance made in the automotive sector to enable the attachment of strips or inserts on parts of the body, but also to hold the interior door panels to the metal door frames. The applications of such components are in any case numerous: for instance snap-fit plastic panels for applying to parts of electric appliances and so on may be made. [004] The components of the known art are usually made in plastic by moulding: the piece extracted from the mould has a portion of covering provided on the inner side, so as to be invisible following assembly, with perforated plates able to house the snap-fit elements.

[005] The snap-fit elements are typically made in plastic or rubber and comprise a coupling portion, preferably snap-fit, which fits under pressure to the relative support and a portion attached to the plate. In the art, the insertion of the coupling element to the relative plate of the component is performed manually. [006] In some cases the operator uses a sort of pneumatic gun which facilitates the insertion operation. [007] The use of robots specially designed for the assembly of such snap-fit elements is also known of.

[008] Such assembly, given the reduced size of the clip and the considerable number of clips used to attach even small components, is slow and laboursome. In fact the clips often break or are projected outside the component and lost in the assembly area with consequent waste of materials and time.

[009] The assembly operations of the components of the known art are therefore slow and expensive. [0010] To overcome the drawbacks mentioned, moulding of the components provided with clips or appendages in one piece with the said components is also known of in the art .

[0011] These embodiments, while on the one hand overcoming the problem of assembly at a later stage of the snap-fit elements, on the other, in the case of breakage of one or more snap-fit elements either during the assembly or dismantling phase, inevitably requires the replacement of the entire component with excessive production and/or servicing costs. [0012] Moreover, the snap-fit elements made in one piece with the component are often subject to breakage during the assembly phase of the component given that the differences of dimensional tolerance between the component and the relative support it is applied to may entail significant distortion and damage to the snap-fit elements in the housing seats. Breakage of the snap-fit elements made in one piece with the component would require replacement of the whole component and therefore lead to unacceptable costs in terms of discards . [0013] The purpose of the present invention is to overcome the drawbacks mentioned with reference to the known art.

[0014] Such drawbacks are overcome by a method according to claim 1 and by a component according to claim 18. [0015] Other embodiments of the method and of the component according to the invention are described in the appended claims .

[0016] Further characteristics and advantages of the present invention will be more evident from the description below, made by way of a preferred and non- limiting example of embodiment, wherein:

[0017] figures 1-4 show schematic cross-section views of the succession of moulding phases of a component according to the method of the present invention; [0018] figure 5 shows a perspective view of a moulded component according to the method of the present invention, provided with a respective coupling element; [0019] figure 6 shows a perspective view of a coupling element of the component in figure 5 ; [0020] figures 7 and 8 show perspective views, from different angles, of a component produced according to the method of the present invention, without the coupling element;

[0021] figure 9 shows an overhead view of the component in figure 7, from the side of the arrow IX in figure 7; [0022] figure 10 shows a cross-section view of the component in figure 7 along the cross-section plane X-X in figure 9. [0023] With reference to the aforesaid figures, reference numeral 4 globally denotes a mould for the moulding of a component 8 provided with a component body 12 and at least one coupling element 16 to attach the component 8 to a relative support (not shown) . The coupling element 16 comprises for instance a coupling head 18 able to engage itself, preferably snap-fitting, onto a relative support of the component 8 and a base 19 to attach the coupling element 16 to the component body 12. Preferably, the head 18 is provided with at least one elastic tab 20 to facilitate snap-fitting to a relative support for the component 8.

[0024] The moulded component 8 may be of any type: for instance it may be the inner panel of the door of a vehicle, a covering panel for the bodywork of a vehicle, the cover panel of an electric appliance and similar. Preferably, one is speaking of plastic panels provided with snap-fit elements which enable them to be attached to a relative support or wall. The snap-fit elements 16 are joined to the component 8 in a detachable manner so as to enable assembly and dismantling. [0025] The uses listed are merely indicative and should in no way be considered restrictive. In other words, the present invention relates to any type of moulded component 8 without limitations as regards form, material or final application. [0026] The method of the present invention comprises the phase of predisposing the mould 4 comprising at least one punch 23, one moulding cavity 24, one hot chamber 28 for the injection of the plastic material. [0027] Preferably, in a closed configuration of the mould 4, the moulding cavity 24 and the punch 23 define a first injection chamber 32 which reproduces the shape of the component body 12 in negative, having at least one plate 36 provided with a seat 40 able to receive said coupling element 16, as further described below. [0028] Preferably, the first injection chamber 32 reproduces the whole component body 12 comprising a number of plates 36 each with a relative seat 40: in other words, the first injection chamber reproduces the component body 12 in one piece. [0029] According to one embodiment, the mould 4 comprises a pair of plugs 48 positioned opposite each other which, in a closed configuration of the mould 4, define the first injection chamber 32. [0030] Preferably, the plugs 48 also define, inside the mould 4, at least one second injection chamber 52 which reproduces in negative the shape of at least one coupling element 16 suitable for inserting in said seat 40. [0031] Advantageously, the second injection chamber 52 is fluidly separate from the first injection chamber 32; in other words the first and the second injection chamber 32,52 are not communicating, in the closed configuration of the mould 4.

[0032] Preferably, the mould 4 comprises a number of second injection chambers 52 each able to mould a respective coupling element 16; all the second injection chambers 52 are fluidly separate from each other and from the first injection chamber 32. [0033] Preferably, the plugs 48 are each made in one piece.

[0034] According to one embodiment, the plugs 48 define with the moulding cavity 24 a portion of the component body 12 so as to identify a number of plates 36 with relative seats 40, the plates 36 being mechanically connected to the component body 12. In other words, the portion defined by the moulding cavity 24 and the plugs 48 forms a communal part of the component body 12 which joins together all the plates 36 provided with the relative seats 40. [0035] Advantageously, the plugs 48 define each seat 40 positioning it in line with the second injection chamber 52 of the corresponding coupling element 16 so as to mould the coupling element 16 in line with the respective housing seat 40. [0036] Preferably, the coupling element 16 and the seat 40 are aligned along an X-X axis parallel to an opening/closing direction of the mould 4. [0037] After closing the mould 4, a first injection of plastic material is made inside the first injection chamber 32 so as to muld the component body 12.

[0038] A second injection of plastic material is then made inside the second injection chamber 52 so as to mould both the component body 12 and the coupling element 16 in the same mould 4 ; consequently the component body 12 and the coupling element 16 are moulded separately and independently of each other.

[0039] In other words, the component body 12 and the coupling element 16 are moulded so as to have no mechanical connection to each other; preferably the component body 12 and the coupling element 16 are made by injecting plastic materials different from each other .

[0040] For instance, the first injection foresees the use of polypropylene for the component body 12 and the second injection foresees the use of polyamide for the snap-fit elements 16. Obviously the materials mentioned are merely indicative and in no way constitute a limitation to the application of the method of the present invention. [0041] Advantageously, between the first injection and the second injection the mould 4 remains closed so as to mould the coupling element 16 in a fixed position aligned with the respective seat 40 of the component body 12, parallel to the axis X-X. [0042] After the second injection the mould 4 is partially opened so as to make available a connection stroke of the coupling element 16 towards the seat thereof 40.

[0043] For instance, the partial aperture of the mould 4 (figure 3) takes place by the reciprocal distancing of the plugs 48 in a transversal direction Y-Y, essentially perpendicular to the connection path of the coupling element 16.

[0044] According to one possible embodiment, the plugs 48 run on respective wedges 54 having equal inclination so as to synchronise the reciprocal movement of the plugs 48 which distance themselves or come closer together in the transversal direction Y-Y while maintaining the same alignment in relation to the X-X axis. [0045] Preferably, the hot chamber 28 comprises an injection head 56 partially counter-shaped in relation to a portion of the coupling element 16 so as to support the coupling element 16 and block it in position even after the partial opening of the mould 4 and during the subsequent connection of the coupling element 16 in its respective seat 40. For instance, the injection head 56 is at least partially counter-shaped to the head 18 of the coupling element 16.

[0046] Advantageously, the injection head 56 can be moved axially in relation to the hot chamber 28 so as to push and connect the coupling element 16 against the seat 40 of the component body 12.

[0047] The insertion of the coupling element 16 into its seat 40 inside the mould 4 (figure 4) is then performed. [0048] Preferably, the connection is by means of a shaped coupling, for instance snap-fit, between the base 19 of the coupling element 16 and the seat 40. For instance, the second injection chamber 52 is shaped so as to create, on the respective coupling element 16, a narrowing 64 defined by the head 18 and by the base 19 which thereby identify a pair of undercuts 68.

[0049] Said necking 64 is able to couple with play in the seat 40 of the component body 12, so as to create with the undercuts 68 a bilateral axial bond between the coupling element 16 and the component body 12.

[0050] Preferably, the necking 64 is smaller than the seat 40 so as to enable the housing of the coupling element 16 inside the seat 40 with play. According to a further embodiment the coupling element 16 comprises a collar 72 positioned between the head 18 and the base 19 so as to form a stop in the insertion of the coupling element 16 in the seat 40. In other words, the collar 72 is bigger than the seat 40 and forms a limit to the insertion path of the coupling element 16 in the seat 40.

[0051] After connecting the various snap-fit elements 16 in their respective seats 40, and having thereby already assembled the component 8, the component 8 is then expelled from the mould 4. [0052] As seen, the component is expelled already assembled and therefore needs no further assembly: in other words it can be . fitted to a relative support straight away using the shaped coupling of the snap-fit elements 16. [0053] As may be seen from the above description, the method of the present invention makes it possible to overcome the drawbacks presented of the known method.

[0054] Specifically, the method makes it possible to produce the component provided with the relative snap- fit elements in a single operation; in fact, upon extraction from the mould, the component comes out already provided with all the snap-fit elements. [0055] This way the subsequent assembly phase of the snap-fit elements is eliminated entirely and the time and cost of producing the said component is considerably reduced.

[0056] In fact, the moulding phase of the component according to the present invention essentially requires the same time as the traditional moulding of the same without the snap-fit elements, with the difference that the subsequent phase of manually assembling the snap-fit elements is avoided.

[0057] The component extracted from the mould can therefore be directly fitted under pressure to the relative panel or support.

[0058] Advantageously, the snap-fit elements are produced by direct moulding inside the mould of the component and therefore cannot be lost in the assembly station with consequent reduction of swarf and costs, as well as time.

[0059] Advantageously, the moulds can be modified so as to change the geometry of the snap-fit elements according to specific requirements . [0060] Advantageously, on completion of moulding, the snap-fit elements are already assembled with the component despite not being one piece with the same and thus being able to move with play in relation to the said component . [0061] This way the assembly operation of the component to the relative support or panel is simplified and the snap-fit elements can adapt, being shifted and/or distorted as needed to the misalignments caused by the differences of dimensional tolerance between the component and the relative support . [0062] The assembly phase of the component to the support is thereby speeded up and the risk that the snap-fit elements may break during the snap-fit assembly phase is reduced. In such case however, the damaged coupling element may be replaced, inserting it manually if required into the relative seat of the component .

[0063] Advantageously, it is possible to mould the snap- fit elements directly in the mould using any polymer material suitable for the specific assembly requirements . [0064] A person skilled in the art may make numerous modifications and variations to the methods described above so as to satisfy specific and contingent requirements while remaining within the scope of protection of the invention as defined by the appended claims .