US20060117535A1

US20060117535A1 - High strength fastening system

Info

Publication number: US20060117535A1
Application number: US10/434,690
Authority: US
Inventors: Derek Fraser; Matthew Baekelandt; Iris Drew; Gerald Morrison
Original assignee: Lear Corp
Current assignee: International Automotive Components Group North America Inc
Priority date: 2003-05-09
Filing date: 2003-05-09
Publication date: 2006-06-08

Abstract

A fastening system for a vehicle is provided. The fastening system includes a metal clip which is easily inserted and removed from a polymeric doghouse. The doghouse is integrally molded with a vehicle interior trim component. After the clip is inserted into the doghouse, the trim component may be snapped into place over a structural pillar by inserting the clip into an aperture and the pillar. The fastening system is designed such that it will not fail, and the trim component will remain in place, when an air bag adjacent to the trim component is deployed. If desired, the trim component can be easily removed from the support pillar by sliding the trim component, and the attached doghouse, away from the clip. The clip can then be removed from the pillar, a new one inserted into the doghouse, and the trim component can be reused.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a high strength fastening system.
2. Background Art
Traditionally, automotive vehicle interior trim components are attached to sheet metal body panels by screws or barbed Christmas tree fasteners. Screws are problematic during installation on a quickly moving assembly line since the power screw drivers often inadvertently disengage the screw head and irreparably mar the adjacent trim panel or bezel. This leads to poor quality or costly removal and scrapping of the expensive trim panel. In addition, insertion of multiple screws is time consuming. Moreover, the installed screws are typically considered to be unattractive and are sometimes hidden by extraneous caps, especially for luxury vehicles. Christmas trees are more aesthetically pleasing and easy to install but are rarely reusable once removed, and are generally not suitable for resisting large pull-out loads.
The proliferation of air bags in vehicles has added a new design consideration that needs to be addressed by designers and manufacturers of trim components. In particular, it is important that trim components do not detach from their support structure when an air bag deploys; otherwise, they may be hurtled toward vehicle occupants. Although the use of screws to secure a trim component to a pillar or roof rail may provide the desired retention strength, the disadvantages of screw attachments are many. In addition, solutions that have been proposed for instrument panel air bags—e.g., tethers attached to the air bag door—may not be suitable for the close confines of a trim component attachment.
Therefore, a need exists for a fastening system that can be used to attach a trim component to a support structure in a vehicle that will provide for fast assembly, while still providing the retention strength necessary to maintain attachment of the trim component to the support structure when an adjacent air bag deploys, and further provides for ease of serviceability, and does not use threaded fasteners to facilitate the attachment of the trim component to the support structure.

SUMMARY OF THE INVENTION

Accordingly, a fastening system is provided that can be used to attach a trim component to a support structure in a vehicle. The fastening system facilitates fast assembly, and provides the retention strength necessary to maintain attachment of the trim component to the support structure when an adjacent air bag deploys; the fastening system further provides for ease of serviceability, and does not rely on threaded fasteners to facilitate attachment of the trim component to the support structure.
The invention further provides a fastening system for a vehicle having a support member and a structure to be fastened to the support member. The fastening system comprises a fastener component including a base and an attachment feature connected to the base. The attachment feature is configured for attachment to the support member. The base includes a rib portion for resisting a bending moment applied to the base. A fastener retaining component is configured for attachment to the structure to be fastened, and further configured to receive and retain the fastener component.
The invention also provides a fastening system for a vehicle having a support member and a structure to be fastened to the support member. The fastening system comprises a fastener component including a generally planar base and an attachment feature connected to the base and configured for attachment to the support member. The base includes a plurality of rib portions for resisting bending moments applied to the base. A fastener retaining component includes a fastener component receiving portion and a plurality of legs configured for attachment to the structure to be fastened. The fastener retaining component further includes a compression member configured to contact the support member when the fastener component is inserted into the support member. The compression member is further configured to deflect upon contact with the support member, thereby inhibiting movement of the fastener retaining component relative to the support structure.
The invention further provides a fastening system for fastening an interior trim component to a support member in a vehicle having a deployable air bag adjacent the trim component. The fastening system comprises a fastener component including a base and an attachment feature connected to the base. The attachment feature is configured for attachment to the support member. The base includes a rib portion for resisting a bending moment applied to the base. A fastener retaining component is integrally molded with the trim component and configured to removably receive the fastener component, thereby facilitating attachment of the trim component to the support member. The fastener retaining component includes two outer legs and an inner leg, each of which is integrally molded with the trim component. At least the inner leg is configured to inhibit deflection of the fastener retaining component when the trim component is fastened to the support member and the air bag deploys.
The above objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an assembly view of a fastening system in accordance with the present invention, the fastening system including a fastener and a doghouse configured to receive the fastener;
FIG. 2 is a partial fragmentary sectional view of the fastener taken through line 2-2 in FIG. 1;
FIG. 3 is an isometric view of the base of the fastener being subjected to a number of bending moments;
FIG. 4 is a partial fragmentary view of a vehicle interior trim component having the doghouse integrally molded thereto;
FIG. 5 is an isometric view of a portion of a vehicle interior, including a structural pillar having the interior trim component attached thereto;
FIG. 6 is a partial fragmentary sectional view of the trim component and structural pillar taken through line 6-6 in FIG. 5; and
FIG. 7 is an assembly view of the fastener base and a number of attachment features which can be used with the base.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a fastening system 10 in accordance with the present invention. The fastening system 10 includes a fastener component, or fastener 12, and a fastener retaining component, commonly called a doghouse 14. The fastener 12 includes a generally planar base 16 and an attachment feature, in this embodiment a clip 18, connected to the base 16. The base 16 includes rib portions, or ribs 20, 22, 24. As explained more fully below, and in particular with reference to FIG. 7, the fastener 12 may include any of a number of different attachment features—e.g., differently configured clips or barbed studs.
The ribs 20, 22, 24 extend below a surface 26 of the base 16. This is shown in FIG. 2, which is a sectional view of the base 16 taken through line 2-2 in FIG. 1. In the embodiment shown in FIG. 1, the fastener 12, including the base 16 and the clip 18, is a one-piece stamped metal component. Thus, as shown in FIG. 2, the rib 20 includes a concave portion 28 extending into the surface 26 of the base 16, and a convex portion 30 extending out from a second surface 32 of the base 16. The other ribs 20, 24, shown in FIG. 1 are similarly configured.
The addition of ribs, such as the ribs 20, 22, 24, help improve the strength of a fastener base, such as the base 16. In particular, the addition of ribs may increase the resistance of an otherwise flat base to bending moments resulting from various loading conditions. For example, FIG. 3 illustrates three bending moments M₁, M₂, M₃applied to the base 16. In the example shown in FIG. 3, each of the ribs 20, 22, 24 help resist a different bending moment experienced by a different portion of the base 16. Of course, the rib configuration shown in FIG. 3 represents only one of many possible rib configurations that could be used to strengthen a fastener base, such as the base 16. For example, more or less than three ribs could be used, or the ribs may have a different shape. As seen in FIG. 2, the rib 20, also representative of ribs 24, 26, has a generally arcuate cross-section extending into the surface 26 and out of the surface 32. A base, such as the base 16, may be manufactured in such a way that a rib has a convex portion extending out of a surface of the base, but does not have a concave portion, such as the concave portion 28, extending into a surface. Moreover, ribs may be configured with non-arcuate shaped cross-sections, for example, they may have rectangular or square cross-sections, just to name two.
As shown in FIG. 1, the doghouse 14 is configured to receive the fastener 12 in a fastener component receiving portion, or first slot 34. Specifically, the first slot 34 is configured to receive the base 16 of the fastener 12. The doghouse 14 also includes a second slot 36 which is configured to receive a portion of the clip 18. In addition to providing increased strength to the base 16, the ribs 20, 22, 24 are also configured to provide an interference fit between the first slot 34 and a base 16.
The doghouse 14 includes a number of legs 38, 40, 42, 44. In the embodiment shown in FIG. 1, the legs 38, 44 may generally be referred to as “outer” legs, and the legs 40, 42 may generally be referred to as “inner” legs. The doghouse 14 also includes outboard members 46, 48, 49. The outboard members 46, 48 are disposed adjacent, and generally perpendicular to, the legs 38, 44, respectively. The outboard members 46, 48, 49 provide additional surface area for attaching the doghouse 14 to a structure, and therefore, may increase the overall retention strength of the doghouse 14. Of course, outboard members could have different configurations to provide more or less attachment area, as desired. Moreover, a doghouse, such as the doghouse 14, may have more or less than three outboard members. As explained more fully below, the fastening system 10 may be well suited for fastening any of a number of different types of structures together. Thus, the legs 38, 40, 42, 44 and the outboard members 46, 48, 49 may be attached to one structure, the fastener 12 inserted into the first slot 34, and the clip 18 inserted into a second structure to fasten the two structures together.
The doghouse 14 may be attached to a structure by any convenient method, such as with an adhesive. In addition, the doghouse 14 may be integrally formed with the structure to be fastened. For example, FIG. 4 shows a portion of a vehicle interior trim component 50 which may be used to cover a vehicle structural support member, such as a pillar. As shown in FIG. 4, the doghouse 14 is integrally molded with the trim component 50. This form of attachment may provide increased strength for the fastening system 10. Where the doghouse 14 is integrally molded with a trim component, such as the trim component 50, it may be convenient to use a single polymeric material for the trim component 50 and the doghouse 14. For example, a polymeric material such as a polycarbonate acrylonitrile butadiene styrene (PC-ABS) may provide the desired properties for both the trim component 50 and the doghouse 14. Of course, other types of polymeric materials may be used, including other types of ABS materials or other polymers, such as a thermoplastic olefin (TPO).
One consideration that may be taken into account when choosing material for a doghouse, such as the doghouse 14, is the required retention capability of the system 10 in extreme loading conditions. For example, FIG. 5 shows a portion of the interior of a vehicle 52. The trim component 50 is attached to a structural support member, or A-pillar 54, which is hidden by the trim component 50. Adjacent the trim component 50, and disposed along a roof rail 56, is a passenger side air bag 58 which is covered by trim components, and therefore not visible in FIG. 5. When an air bag, such as the air bag 58, deploys after a vehicle impact, trim components adjacent the air bag that are not well secured to structural members, may be forcibly detached as the air bag deploys.
The fastening system 10 may be configured to maintain attachment of the trim component 50 to the A-pillar 54 even in the event of air bag deployment. In particular, the fastening system 10 is configured to withstand at least 100 pounds of pull-out force without failing. The term “without failing”, as used here, implies that neither the fastener 12, nor the doghouse 14, will catastrophically fail, become separated from each other, or deform to such an extent that the trim component 50 detaches from the A-pillar 54. The retention strength of a fastening system, such as the fastening system 10, may depend on a number of factors, such as the materials used for the fastener and the doghouse, as well as the configuration of each component. For example, the number and location of legs and outboard members may affect the ability of the doghouse to withstand pull-out loads. Similarly, the size and location of ribs on a fastener base, and the thickness of the base, may affect the ability of the fastener to withstand pull-out loads.
FIG. 6 shows a section of the A-pillar 54 and the fastening system 10 taken through line 6-6 in FIG. 5. In order to illustrate the attachment of the fastening system 10 to the A-pillar 54, the trim component 50 has been removed for clarity. As can be readily seen in FIG. 6, the fastening system 10 can be attached to a structural member, such as the A-pillar 54, by inserting the clip 18 through an aperture 60. The clip 18 deflects slightly as it is pushed through the aperture 60, and when fully inserted, wings 62 hold the clip 18 securely in the A-pillar 54. Of course, the clip 18 is but one of many different types of attachment features which may be used with the base 16. For example, FIG. 7 is an exploded view showing a group of attachment features 62, any one of which may be used with the base 16. For example, clips 64, 66, 68, are variations of the clip 18, which may be attached to, or integrally formed with, the base 16. In addition, barbed studs 70, 72 may also be used with the base 16. The choice of an appropriate attachment feature may depend on a number of considerations, including the desired retention strength and the ease by which the fastener itself may be manufactured. For example, the clip 18 and the base 16 may be a unitary structure formed in a stamping process using a spring steel material. Of course, a fastener, such as the fastener 12, need not be a unitary structure, but rather, may have a base and an attachment feature connected in a secondary process.
As described above, a doghouse, such as the doghouse 14, may be made from a polymeric material and integrally molded with a trim component, such as the trim component 50. Although a doghouse used with a fastening system, such as the fastening system 10, may have any one of a number of configurations, the doghouse 14 may be particularly well suited to the molding process. For example, each of the legs 38, 40, 42, 44 and outboard members 46, 48, 49 have a generally uniform thickness, which may be desirable in a molding process. In addition, the first slot 34 includes a generally planar surface 74 which is generally perpendicular to the legs 38, 40, 42, 44. The surface 74 is part of a horizontal (as oriented in FIG. 1) member 76 which also has a thickness approximately the same as the legs and outboard members. Moreover, the first slot 34 is at least partially defined by the surface 74 and two retaining members 78, 80 disposed opposite the surface 74. The retaining members 78, 80 are also configured with a thickness that is the same, or nearly the same, as the thickness of the other members of the doghouse 14.
It is worth noting that the number and general location of the legs and outboard members may vary in different doghouse configurations. For example, the legs 40, 42 help inhibit the deflection of the horizontal member 76 when a pull-out load is applied to the fastening system 10. In an application where more or less deflection is allowable, fewer legs or more legs may be used, as desired. The same is true for the outboard members, which may also have different configurations, such as a smaller or greater “footprint”, thereby reducing or increasing the attachment area, as desired.
As shown in FIG. 1, the fastener 12 may be easily slid into the slot 34 on the doghouse 14. Where the doghouse 14 is attached to a trim component, such as the trim component 50, assembly of the trim component to a structural support member is a simple matter of pressing the clip 18 into an aperture, such as the aperture 60 shown in FIG. 6. Thus, assembly of the trim component to the structural support member may be performed quickly and easily. The fastening system 10 also provides for easy replacement of the trim component or the fastener, if such replacement is needed. For example, if the trim component becomes damaged, or it is desired to replace the fastener after an air bag deploys, the trim component may be easily removed for replacement, or to allow access to the clip. In FIG. 6, it may be observed that moving the trim piece, and subsequently the doghouse 14, in the direction of the arrow will allow the doghouse 14 to be slidably removed from the base 16 of the fastener 12. The clip 18 could then be removed from the aperture 60 and a new clip used with the same trim component, or an entirely new trim component and fastener may be employed.
Because a fastening system, such as the fastening system 10, may be used to attach components in a vehicle, some consideration may be given to the potential problem of buzz, squeak, and rattle (BSR). To help ensure that a trim component, such as the trim component 50, does not move against a support member, such as the A-pillar 54, the doghouse 14 is provided with compression members 82, 84, see FIGS. 1 and 6. In the embodiment shown in FIGS. 1 and 6, the compression members 82, 84 are cantilevered structures integrally molded with the doghouse 14. The compression members 82, 84 are disposed on either side of the second slot 36, and they extend outward from the doghouse 14 generally in the direction the clip 12 will be inserted into the A-pillar 54. The compression members 82, 84 are configured to contact a support member, such as the A-pillar 54, when the clip 12 is inserted through an aperture in the support member. As seen in FIG. 6, the compression members 82, 84 deflect upon contact with the A-pillar 54 when the clip 12 is inserted through the aperture 60. The cantilever design of the compression members 82, 84 facilitates spring-like movement which helps to maintain contact between them and the A-pillar 54. This type of contact reduces or eliminates movement of the doghouse relative to the A-pillar 54, thereby addressing BSR issues. Of course, additional compression members may be added, or a single compression member may be used in different configurations of a doghouse.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.

Claims

1. A fastening system for a vehicle having a support member and a structure to be fastened to the support member, the fastening system comprising:

a fastener component including a base and an attachment feature connected to the base, the attachment feature being configured for attachment to the support member, the base including a rib portion for resisting a bending moment applied to the base; and

a fastener retaining component configured for attachment to the structure to be fastened, and further configured to receive and retain the fastener component.

2. The fastening system of claim 1, wherein the fastener retaining component includes a first slot configured to receive the base, and a second slot configured to receive a portion of the attachment feature; and

wherein the rib portion is configured to provide an interference fit between the base and the first slot.

3. The fastening system of claim 1, wherein the fastener retaining component includes two outer legs and an inner leg disposed between the outer legs, each of the legs being integrally molded with the structure to be fastened, and at least the inner leg being configured to inhibit deflection of the fastener retaining component.

4. The fastening system of claim 1, wherein the support member is an automotive vehicle structural pillar, and the structure to be fastened is a pillar trim component.

5. The fastening system of claim 1, wherein the fastener component and the fastener retaining component are configured to accept at least 100 pounds of pull-out force without failure.

6. The fastening system of claim 1, wherein the fastener component is a unitary structure comprising a spring steel material, and the fastener retaining component comprises a polymeric material.

7. The fastening system of claim 1, wherein the fastener retaining component includes a compression member configured to contact the support member when the fastener component is inserted into the support member, and to deflect upon contact with the support member, thereby inhibiting movement of the fastener retaining component relative to the support structure.

8. The fastening system of claim 1, wherein the fastener retaining component further includes a generally planar surface disposed generally perpendicular to the legs and configured for contact with at least a portion of the base when the fastener component is received by the fastener retaining component.

9. The fastening system of claim 8, wherein the fastener retaining component further includes an outboard support member configured for attachment to the structure to be fastened, the outboard support member being disposed adjacent a leg.

10. A fastening system for a vehicle having a support member and a structure to be fastened to the support member, the fastening system comprising:

a fastener component including a generally planer base and an attachment feature connected to the base and configured for attachment to the support member, the base including a plurality of rib portions for resisting bending moments applied to the base; and

a fastener retaining component including a fastener component receiving portion and a plurality of legs configured for attachment to the structure to be fastened, the fastener retaining component further including a compression member configured to contact the support member when the fastener component is inserted into the support member, and to deflect upon contact with the support member, thereby inhibiting movement of the fastener retaining component relative to the support structure.

11. The fastening system of claim 10, wherein the fastener component receiving portion is configured to replaceably receive the base, and at least one of the rib portions is configured to provide an interference fit between the fastener component receiving portion and the base.

12. The fastening system of claim 11, wherein the fastener component receiving portion is defined by a generally planar surface and a pair of retaining members disposed opposite the generally planar surface.

13. The fastening system of claim 10, further comprising a plurality of compression members configured to reduce the movement of the fastener retaining component relative to the support structure.

14. The fastening system of claim 10, wherein the fastener retaining component is integral with the structure to be fastened.

15. The fastening system of claim 10, wherein the support member is an automotive vehicle structural pillar, and the structure to be fastened is a pillar trim component.

16. The fastening system of claim 10, wherein the fastener component and the fastener retaining component are configured to accept at least 100 pounds of pull-out force without failure.

17. A fastening system for fastening an interior trim component to a support member in a vehicle having a deployable air bag adjacent the trim component, the fastening system comprising:

a fastener retaining component integrally molded with the trim component and configured to removably receive the fastener component, thereby facilitating attachment of the trim component to the support member, the fastener retaining component including two outer legs and an inner leg, each of the legs being integrally molded with the trim component, and at least the inner leg being configured to inhibit deflection of the fastener retaining component when the trim component is fastened to the support member and the air bag deploys.

18. The fastening system of claim 17, wherein the attachment feature is configured to remain attached to the support member, and the base is configured to remain attached to the fastener retaining component when the trim component is fastened to the support member and the air bag deploys.

19. The fastening system of claim 17, wherein the attachment feature is configured for insertion into an aperture in the support member, thereby facilitating snap-fit attachment of the trim component to the support member after the fastener component is received by the fastener retaining component.

20. The fastening system of claim 19, wherein the trim component is slidably removable from the support member, thereby facilitating removal of the fastener component from the support member after the air bag deploys, and further facilitating subsequent reattachment of the trim component to the support member with a different fastener component.