Plastics fastener to attach door trim panel

Abstract: A retainer (22) for receiving a fastener (24) therein, and adapted for loading into a mould (16) for embedment in a trim article (10) moulded from moulding material (14). The retainer (22) has a housing having an upper portion (50) for accepting the fastener (24) and a lower portion (52) for embedment in the moulded trim article (10). A flexible lip (66) encompasses the housing for sealingly engaging with the mould (16) thereby preventing the moulding material (14) from making contact with the upper portion (50) of the housing whilst allowing the moulding material (14) to make contact with the lower portion (52) of the housing.

Description: The invention relates to a retainer for embedment in a moulded trim article and more particularly provides a retainer as specified in the preamble of claim 1, for example as disclosed in US-A-4,400,336. Door trim panels in motor vehicles are conventionally comprised of a paper-board base which is covered with a vinyl or cloth cover material. Apertures are provided in the paper-board base for receiving a threaded head of a conventional plastics fastener. Such a fastener has a plurality of conical barbs which are pressed into openings in the steel door inner panel to attach the trim panel to the door. An alternative desirable door inner trim panel construction is the substitution of a moulded foam base for the paper-board base. In such a door trim panel construction, a sheet of plastics material is placed in a mould and then plastics foam is injected between the sheet and a mould portion spaced from the sheet at a distance providing the desired thickness of the foam base. A disadvantage of such a moulded foam base is that the foam material does not provide a suitable anchorage for the threaded head of the conventional fastener. It has been recognized as necessary and desirable to embed a plastics retainer in the foam base during the moulding process so that the fastener can be mounted on the retainer. Such a retainer is formed of injection-moulded plastics material and has an opening in the face thereof through which the threaded head enters a slot into a cavity. It has also been recognized as necessary to block the slot and cavity of the retainer from the flow of moulding material entering the mould during the moulding process, so that the cavity will not become filled with moulding material. According to the prior art, walls were formed in the mould to cover the cavity in the plastics retainer. It would be desirable to provide a retainer which could sealingly engage the mould and prevent moulding material making contact with the portion of the retainer that has the slot and the cavity formed therein. A retainer according to the present invention is characterised by the features specified in the characterising portion of claim 1. This invention provides a retainer for receiving a fastener and adapted for loading into a mould for embedment in a trim article moulded of moulding material. The retainer has a housing having an upper portion for accepting the fastener and a lower portion for embedment in the moulded trim article. A flexible lip encompasses the housing for sealingly engaging with the mould, thereby preventing the moulding material from making contact with the upper portion of the housing and allowing the moulding material to make contact with the lower portion of the housing. An object, feature and advantage of the invention is the provision of a flexible lip encompassing the housing of the retainer and adjoining an upper surface of the retainer. The flexible lip and the upper surface of the retainer sealingly engage and position the retainer in the mould to prevent the moulding material from making contact with the upper portion of the housing and to allow the moulding material to make contact with the lower portion of the housing and prevent the retainer from being pushed up too far in the mould. The invention and how it may be performed are hereinafter particularly described with reference to the accompanying drawings, in which: Figure 1 is an elevational sectional view of a first embodiment of a retainer according to the present invention embedded in a moulded trim panel located in a mould. Figure 2 is an isometric view of the fastener and the retainer shown in Figure 1; Figure 3 is a sectional view taken in the direction of arrows 3-3 of Fig. 1; Figure 4 is an elevational view of a second embodiment of a retainer and fastener; and Figure 5 is an elevation view of a third embodiment of a retainer and fastener. As shown in Figure 1, a moulded door panel 10 includes a sheet 12 of cloth or vinyl or other plastics material which is backed by a foam base 14 of a glass-reinforced polyurethane material. To mould the door panel 10, the sheet 12 is laid in a mould 16 and the glass-reinforced polyurethane material is injected to form the foam base 14 as shown in Figure 1. The mould 16 has a lower mould 18 on which the sheet 12 is laid, and an upper core 20. The upper core 20 has a bushing 26 with a bushing cavity 28 which receives and holds a retainer 22 and a fastener 24 during the moulding process. As shown in Figure 1, a recess is formed in the bushing 26 at the bottom of the bushing cavity 28 and defines a radial shoulder 36 and an axial wall 32 which co-operate to seat the retainer 22 as will be discussed hereinafter. The fastener 24 is a conventional fastener for attaching the door panel to the door. As best seen in Figure 2, the fastener 24 has a cylindrical trunk 40 with a base 42 at one end to be threaded into the retainer 22 and a tip 48 located at the other end. Directional teeth in the form of conical barbs 46 are moulded on the fastener 24 and pushed through a hole in the steel door panel to retain the door panel 10 to the door. A skirt 44 of the fastener 24 yieldably pushes against the steel door panel to limit insertion of the fastener 24 and to yieldably position the cylindrical trunk 40 such that one of the conical barbs 46 is firmly seated against the steel door panel to provide a firm attachment of the fastener 24 with the steel door panel. The retainer 22 has a circular upper portion 50 and a circular lower, base portion 52 as shown in Figures 1 and 2. A pair of risers 54 and 56 separate the lower portion 52 from the upper portion 50 and define a cavity 60. The upper portion 50 has a slot 58 which is elongated. The base 42 of the fastener 24 is threaded into the elongated slot 58 so that fastener 24 has a certain amount of movement relative to the retainer 22. The retainer 22 has a plurality of dovetail slots 62 located on the underside of the lower portion 52 as seen in Figures 1 and 2. The glass-reinforced polyurethane material flows into the dovetail slots 52 and cures therein, so that the inverted "V" shape of the dovetail slots 52 not only give more surface area for the foam base 14 to adhere to, but also causes the foam base 14 to mechanically grip the retainer 22. The lower portion 52 also has an indentation 64, as shown in Figure 1 and in hidden lines in Figure 3, which can be gripped by a loading tool, not shown, for automated loading of the retainer 22 into the mould 16. The lower portion 52 has a flexible lip 66 that encompasses and is integral to the lower portion 52 of the retainer 22 as shown in Figure 2. When the retainer 22 is loaded into the bushing 26, as shown in Figure 1, the flexible lip 66 is flexed and sealingly engages the axial wall 32 of the bushing 26. The circular shape of the retainer 22 facilitates insertion thereof into the bushing 26. The lower portion 52 has an upper surface 68 which engages with the radial shoulder 36 of the bushing 26 and locates the retainer 22 and prevents the retainer 22 from being pushed up too far in the bushing cavity 28. In order to mould the door panel 10, the sheet 12 is laid on the lower mould 18. The retainer 22 with the fastener 24 threaded therein is then inserted into the bushing cavity 28. Alternatively, the fastener 24 can be threaded into the slot 58 of the retainer 22 after the door panel 10 is moulded. The retainer 22 is held in the bushing 26 by the flexible lip 66 pressing against the axial wall 32 of the bushing 26. The upper core 20 and lower mould 18 are then mated together. As the glass-reinforced polyurethane material which forms the foam base 14 enters the mould 16, the retainer 22, which already holds the fastener 24, is pressed against the radial shoulder 36 of the bushing 26. The flexible lip 66 yieldably moves up and towards the axial wall 32 when the polyurethane material presses against the underside thereof, thereby sealingly preventing the polyurethane material from entering behind the flexible lip 66. Accordingly the flexible lip 66 prevents the polyurethane material from fouling the bushing cavity 28, the conical barbs 46 of the fastener 24 or the cavity 60 of the retainer 22. The glass-reinforced polyurethane material of the foam base 14 is cured with a portion thereof locked in the dovetail slots 62. After the glass-reinforced polyurethane material is cured, the mould 16 is opened and the moulded door panel 10 with the retainer 22 is removed from the mould 16. A second embodiment of the invention, shown in Figure 4, has a retainer 70 that accepts a fastener 24 identical to that shown in the first embodiment in Figures 1, 2 and 3. The retainer 70 has a circular upper portion 72, a circular middle portion 74 and a circular lower portion 76. A pair of risers 78 and 80 separate the middle portion 74 from the upper portion 72 and defines a cavity 84 therebetween. The upper portion 72 has a slot 82 through which the base 42 of the fastener 24 is threaded. The lower portion 76 is connected to the middle portion 74 by a set of legs 86, 87 and 88 and forms a base portion 75. The lower portion 76 has a series of dovetail slots 90 formed in the underside to facilitate the embedment of the retainer 70 in the glass-reinforced polyurethane material of foam base 14 similar to the first embodiment. The middle portion 74 has a flexible lip 92 that encompasses the retainer 70. The flexible lip 92 is received by the bushing 26 and sealingly engages with the axial wall 32 of the bushing 26 in a similar manner to the first embodiment shown in Figure 1. The middle portion 74 has an upper surface 94 which makes contact with the radial shoulder 36 of the bushing 26 and locates the retainer 70 and prevents the retainer 70 from being pushed up too far in the bushing cavity 28. The retainer of the second embodiment is used when the steel door panel, not shown, is spaced at a distance from the desired location of the door panel 10. The legs 86, 87 and 88 establish the lower portion 76 in proximity with the sheet 12 so that the polyurethane material interposed therebetween is relatively thin to assure dimensional stability irrespective of shrinkage of the material during curing. Accordingly, the glass-reinforced polyurethane material that flows past the lower portion 76 and into the space between the middle portion and lower portion may shrink upon curing, without affecting the distance between the retainer 70 and the moulded door panel 10. The length of the legs 86, 87 and 88 is selected in accordance with the distance between the moulded door panel 10 and the steel door panel. A third embodiment of the invention, shown in Figure 5, has a retainer 100 that mounts a fastener 24. The retainer 100 has a circular upper portion 102, a circular middle portion 104 and a circular lower portion 106 similar to the second embodiment. A pair of risers 108 and 110 separate the middle portion 104 from the upper portion 102 and defines a cavity 114 therebetween. The upper portion 102 has a slot 112 through which the base 42 of the fastener 24 is threaded. The lower portion 106 is connected to the middle portion 104 by a set of legs 116, 117 and 118 and forms a base portion 105. The lower portion 106 has a series of dovetail slots 120 formed therein to facilitate the embedment of the retainer 100 in the glass-reinforced polyurethane material of foam base 14. The lower portion 106 has a flexible lip 126 that encompasses the retainer 100 and sealingly engages the axial wall 32 of the bushing 26 in a similar manner to the first embodiment shown in Figure 1. The middle portion 104 has an upper surface 128 which makes contact with the radial shoulder 36 of the bushing 26 and locates the retainer 100 and prevents the retainer 100 from being pushed too far up in the bushing cavity 28. The retainer of the third embodiment is also used when the steel door panel is spaced at a distance from the moulded door panel 10. The purpose of the legs 116, 117 and 118 is similar to the those given in the second embodiment establishing the lower portion 106 in proximity with the sheet 12. The flexible lip 126 prevents the glass-reinforced polyurethane material of foam base 14 from flowing past the lower portion 106 and into the space between the lower portion 106 and the middle portion 104. This embodiment would require the use of a bushing 26 having an axial wall surface 32 of greater length than with the second embodiment, because the flexible lip 126 is provided on the lower portion 106 and the upper surface 128 is provided on the middle portion 104. Thus both the second and third embodiments allow the moulded door panel 10 to be at a distance from the steel door whilst the flexible lip prevents any glass-reinforced polyurethane material from making contact and interfering with the fastener 24 and the slot and cavity of the upper portion of the retainer. Whilst three embodiments of the present invention have been specifically described, various modifications within the scope of the following claims will be readily apparent to those skilled in the art. For example, the sheet 12 of cloth or vinyl or other plastics material may be eliminated by moulding the foam base 14 from a moulding material which provides a surface suitably decorative and durable as to provide the inner surface of the door.

Claims: A retainer (22;70;100) for receiving a fastener (24) and adapted for loading into a mould (16) for embedment in a trim article (10) moulded of moulding material (14), said retainer (22;70;100) comprising a housing having an upper portion (50;72;102) for accepting the fastener (24) and a lower portion (52;75;106) for embedment in the moulded trim article (10), characterised in that said retainer includes a flexible lip (66;92;126) encompassing the housing for sealingly engaging with the mould (16), thereby preventing the moulding material (14) from making contact with the upper portion (50;72;105) of the housing whilst allowing the moulding material (14) to make contact with the lower portion (52;75;106) of the housing. A retainer (22;70;100) according to claim 1, in which the upper portion of the housing is an apertured upper portion (50;72;102) communicating with a cavity (60;84;114) for accepting the fastener (24); characterised in that said lower portion is a base portion (52;75;106) for embedment in the moulded trim article (10), and said flexible lip (66;92;126) encompasses the base portion (52;75;106) and flexibly engages with an upper portion (26) of the mould (16) to seal the base portion (52;75;106) against the mould (16) and thereby prevent the passage of moulding material (14) into the fastener-receiving cavity (60;84;114). A retainer (22;70;100) according to claim 1 or 2, characterised in that the retainer (22;70;100) is made of a moulded plastics material and the flexible lip (66;92;126) is integral with the retainer (22;70;100). A retainer (22;70;100) according to any one of the preceding claims, characterised in that the portion of the housing of the retainer (22;70;100) that is encompassed by the flexible lip (66;92;126) is circular in cross-section, so as to allow for symmetrical acceptance of the retainer (22;70;100) in a cavity (28) of the mould (16) without any requirement for circumferential alignment of the retainer (22;70;100) within said cavity (28) prior to the moulding of said trim article (10). A retainer (22;70;100) according to any one of the preceding claims, characterised in that the retainer (22;70;100) has dovetail slots (62;90;120) formed in the lower portion (52;76;106) thereof for increasing the surface contact thereof with the moulding material (14). A retainer (22;70;100) according to any one of the preceding claims, characterised in that the retainer (22;70;100) has a shoulder (36;94;128) formed on the lower portion (52;75;105) thereof for axially locating the retainer (22;70;100) in a cavity (28) of the mould (16).

Inventors: REYNOLDS JOHN JOSEPH, STEIN ARTHUR CARL, REYNOLDS, JOHN JOSEPH, STEIN, ARTHUR CARL
Applicants: GEN MOTORS CORP, GENERAL MOTORS CORPORATION
Application year: 1991
Main classification: B29C33
IPC codes: B60R13, B29C33, B29C45, B29L31, F16B5, B60J5