Energy absorbing tether clip

Abstract

A releasable fastener includes a tether and a clip adapted to be coupled to a first member. The tether has a first end releasably coupled to the clip, a second end adapted to be coupled to a second member that is moveable relative to the first member and a flexible member having first and second strands interconnecting the first and second ends of the tether. The second strand is frangible.

Description

FIELD

The present disclosure relates in general to clip type fasteners and more specifically to a device and method for creating and using a clip type fastener assembly to join automobile vehicle component parts.

BACKGROUND

A variety of fasteners have been used within automotive applications to join trim pieces to other portions of the automobile. Sometimes these fasteners are required to be insertable into apertures of the automobile and meet requirements to both retain the trim piece and allow the trim piece to be later removed if replacement is desired. For example, in the event that an air bag has been deployed, replacement of the air bag and/or the trim piece supporting the air bag is typically required. To replace the trim piece, the fasteners attaching the trim piece to the automobile also need to be removable. Unfortunately, many available fasteners do not provide an easily accessible fastener joint to allow removal of the fastener/trim piece following damage or an air bag deployment event.

Many vehicles are currently equipped with numerous airbags or air curtains. Based on the variety of sizes of airbags being installed, a number of special fasteners have been created to retain the trim piece enclosing the escape aperture of the airbag. Furthermore, the use of side curtain airbags has further increased the range of thicknesses of the packed airbags currently manufactured.

Other concerns relate to excessive trim piece movement during or after air curtain deployment. In particular, it may be desirable to restrict the trim piece from moving once the air curtain has been fully deployed. Accordingly, there may be a need for a single solution fastener for use with a number of airbag designs having various thicknesses and escape aperture size requirements. In addition, it may be beneficial to provide a compact tethered design for packaging while providing a relatively long tether length during airbag deployment.

SUMMARY

A releasable fastener includes a tether and a clip adapted to be coupled to a first member. The tether has a first end releasably coupled to the clip, a second end adapted to be coupled to a second member that is moveable relative to the first member and a flexible member having first and second strands interconnecting the first and second ends of the tether. The second strand is frangible.

In addition, the present disclosure relates to a releasable fastener including a first connector having a male pin, a second connector flexibly tethered to the first connector and a clip releasably engageable with the second connector. The second connector has a receptacle and at least one biasing element operable to releasably engage the male pin. The flexible tether includes first and second strands where each strand has one end proximate to the first connector and an opposite end proximate to the second connector. The second strand is separable under a tensile load. The first strand continues to interconnect the first and second connectors when subject to the tensile load.

Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

FIG. 1 is a perspective view of an assembled tethered fastener according to the present disclosure;

FIG. 2 is a perspective view of a tether of the fastener of FIG. 1;

FIG. 3 is another perspective view of the tether of the fastener of FIG. 1;

FIG. 4 is a perspective view of a clip portion of the fastener of FIG. 1;

FIG. 5 is a side elevational view of an assembled fastener of the present disclosure;

FIG. 6 is a perspective view of a doghouse portion of an automotive component; and

FIG. 7 is a side view of another tether of a fastener.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

Referring to FIGS. 1-4, a connecting tethered fastener assembly 10 includes a tether 12 and a clip 14. Clip 14 is coupled to a vehicle panel 16. Tether 12 includes a first end 18 coupled to a moveable component 20 of the vehicle such as a trim piece associated with air bag deployment. A second end 22 of tether 12 is coupled to clip 14. A flexible element 24 interconnects first end 18 and second end 22.

Second end 22 of flexible element 24 includes a substantially U-shaped connector 30 including a first planar portion 32 and a second planar portion 34. First and second planar portions 32 and 34 are arranged substantially parallel to each other and define a partial slot 36 and a solid section 38 between first planar portion 32 and second planar portion 34. A freely extending end of second planar portion 34 provides a hooked end 40 having a partial cavity 42 and a rounded leading edge 44. Partial cavity 42 includes stop face 45. A pin 46 defines a longitudinal axis “Y” which is oriented substantially perpendicular to a plane defined by a face 48 of first planar portion 32. Pin 46 is sized to be slidably received within an aperture 50 created in clip 14.

Pin 46 includes a bulbous head 64 having a head diameter “A”. Head 64 is connected by a taper portion 66 to a stem 68. Stem 68 includes a stem diameter “C” which is smaller than head diameter “A”. Head diameter “A” of pin 46 is sized to clear aperture 50 formed in clip 14. Head diameter “A” of pin 46 is further sized to releasably engage within a stepped receptacle 70 formed in an engagement member 69 formed at first end 18. Stepped receptacle 70 includes a plurality of stepped deflecting members 72 separated from one another by a plurality of channels 74. Each stepped deflecting member 72 includes a beveled contact surface 76 and an engagement surface 78. Head 64 of pin 46 elastically deflects each stepped deflecting member 72 as head 64 is inserted into stepped receptacle 70. When head 64 extends beyond engagement surfaces 78, the elastic bias force of stepped deflecting members 72 direct engagement surfaces 78 into contact with taper portion 66 of stem 68 to releasably engage connector 30 to engagement member 69 through clip 14.

Engagement member 69 includes a shoulder 79 at a first end having each of a first post 80 and a second post 82 transversely extending beyond each of a pair of side walls 84. A post clearance width “D” is sized to receive a width of first planar portion 32 of connector 30. First and second posts 80,82 provide an anti-rotational feature to prevent connector 30 from rotating with respect to engagement member 69 when pin 46 is received within stepped receptacle 70. Engagement member 69 also provides a substantially flat engagement section 86 and a deflectable tab 88.

Clip 14 engages shoulder 79 of engagement member 69. Clip 14 further includes a mounting plate 92 through which an aperture 94 is formed. Mounting plate 92 integrally includes each of a first contact side 96 and a second contact side 98. First and second contact sides 96 and 98 extend substantially transverse to mounting plate 92. First contact side 96 and second contact side 98 of clip 14 extend generally transversely from mounting plate 92. First contact side 96 includes a first exterior frame section 100, a second exterior frame section 102, and at least one first deflectable wing 104 integrally connectable to a cross member 106 distally extending from mounting plate 92. Cross member 106 is coupled to a cross member 108 of second contact side 98 by a first retaining tab 110 integrally formed with cross member 106 and a second retaining tab 112 integrally formed with cross member 108. Each of first retaining tab 110 and second retaining tab 112 are deformed such that they interlock as shown with the opposed cross member 106 or 108.

First exterior frame section 100 is integrally connected to mounting plate 92 by a first side wall 114. Similarly, second exterior frame section 102 is integrally connected to mounting plate 92 by a second side wall 116. First side wall 114 and second side wall 116 each oppose a third side wall 118 integrally connected to second contact side 98. A receiving channel 120 is defined between first side wall 114, second side wall 116, and third side wall 118. Receiving channel 120 is configured to slidably receive engagement member 69 when assembled. Second contact side 98 further includes a first interior frame section 122 and a second interior frame section 124 which are similar to first exterior frame section 100 and second exterior frame section 102. Second contact side 98 also includes at least two deflectable wings which are positioned opposite to first deflectable wing 104, including a second deflectable wing 126 and a third deflectable wing 128.

As best seen in FIG. 5, each of the main component parts of fastener assembly 10 of the present invention are shown in an assembled condition. Clip 14 is slidably engaged with engagement member 69. More specifically, deflectable tab 88 deflects to receive clip 14. Connector 30 is rotated such that pin 46 engages stepped receptacle 70. Pin 46 is insertable into both aperture 50 of clip 14 and stepped receptacle 70. Clip 14 positioned between first and second posts 80,82 and deflectable tab 88.

After fastener assembly 10 is assembled, each of first contact side 96 and second contact side 98 of clip 14 are slidably inserted into an aperture 130 formed within vehicle panel 16. Each of first deflectable wing 104, second deflectable wing 126 and third deflectable wing 128 deflect upon insertion into aperture 130 and elastically return to a non-deflected or expanded state following insertion. First deflectable wing 104, second deflectable wing 126, and third deflectable wing 128 engage a first surface 132 of panel 16, while a plurality of plate engagement members 134 engage an opposed or second surface 136 of panel 16.

FIG. 6 depicts a rectangular shaped doghouse 138 includes a flat face 140 having an aperture 142 adapted to receive hooked end 40 of connector 30. Doghouse 138 is coupled to component 20. Hooked end 40 is positioned outside of doghouse 138 and positively engages flat face 140 to resist separation from doghouse 138 unless hooked end 40 is deflected in a direction “E”. Solid section 38 is positioned within a detent 144 formed within a wall 146 of doghouse 138. When hooked end 40 is positioned as shown, stop face 45 and solid section 38 each resist translation of doghouse 138 relative to connector 30. Hooked end 40 in engagement with doghouse 138 defines another releasable joint of fastener assembly 10.

Four primary releasable connections are formed when using fastener assembly 10 to join component 20 to panel 16 of a vehicle. The releasable connections define a sequential or ascending order of joint integral strength. A first releasable connection 145 is formed between pin 46 and stepped receptacle 70. A second releasable connection 147 is formed between hooked end 40 and aperture 142 of doghouse 138. Second releasable connection 147 physically joins doghouse 138 to connector 30. This releasable connection is designed to release within a sequential order after first releasable connection 145 to allow repair or replacement of the trim panel. A third releasable connection 148 is formed between clip 14 and engagement member 69. A fourth releasable connection 149 is formed by contact between first deflectable wing 104, second deflectable wing 126, and third deflectable wing 128 of clip 14 and panel 16. The retention strength of each of the releasable connections increases from first releasable connection 145 to the fourth releasable connection 149, wherein each successive releasable connection forms a stronger joint than the joint(s) preceding it. In other words, the first releasable connection intended to disengage or be disengaged in use is first releasable connection 145. One purpose for providing individual joining strengths for each of the releasable connections of the present invention is to allow, for example, a component part such as a trim panel to separate from a body panel of a vehicle in the event that an air bag associated with the trim panel deploys. By designing first releasable connection 145 to separate first, flexible element 24 will continue to retain component 20 via doghouse 138 to panel 16.

During airbag deployment, and after first releasable connection has released, frangible strands of flexible element 24 separate to allow proper airbag deployment. Flexible element 24 includes a main strand 150 interconnecting connector 30 and engagement member 69. A second strand 152 is positioned in parallel with main strand 150 and also interconnects connector 30 with engagement member 69. Main strand 150 is longer than secondary strand 152. In addition, main strand 150 may have a thickness 154 greater than a nominal thickness 156 of secondary strand 152. Sections 158 of secondary strand 152 may have a further reduced thickness than section 156.

Upon airbag deployment, first releasable connection 145 is disconnected where pin 46 is released from engagement with stepped receptacle 70. Flexible member 24 begins to extend as the airbag continues to deploy. As flexible member 24 extends, secondary strand 152 becomes taut and subsequently separates at one of reduced thickness sections 158. Secondary strand 152 separates allowing the extended length of flexible element 24 to increase and allow an opening (not shown) for the airbag to pass through to become larger. Once the widest portion of the still deploying airbag passes through the opening, the airbag no longer applies a force to the component 20. However, component 20 continues to move with its own momentum being a function of its mass and velocity. At this time, main strand 150 begins to arrest the momentum of component 20. Main strand 150 maintains an interconnection between connector 30 and engagement member 69.

FIG. 7 depicts another tether 200 including a flexible element 201. Tether 200 is substantially similar to tether 12. Accordingly, like elements will be identified with similar reference numerals having a prime suffix. Tether 200 includes a third strand 202 and a fourth strand 204 in addition to main strand 150′ and secondary strand 152′. In flexible element 201, fourth strand 204 is the shortest of all strands. Third strand 202 is the next longest strand while secondary strand 152′ is second longest, shorter only than main strand 150′. By arranging the strands in this manner, tensile loading between first end 18 and second end 22 will be sequentially placed across fourth strand 204, third strand 202, secondary strand 152 and lastly main strand 150. One or more strands may separate depending on the mass of the movable component 20 and the impulse of force onto component 20 from the airbag as it deploys. Each of the strands 150′, 152′, 202 and 204 may be formed to include different thicknesses or widths as well. Strands 152′, 202 and 204 may also include localized reduced section thicknesses similar to portions 158 formed on secondary strand 152. Each of the variances in structure between the strands causes each strand to separate at a different tensile force.

An alternative way to accomplish strand separation at various tensile forces includes molding the strands from different materials. A multi-shot injection mold may be utilized to construct one or more of the strands from a first material and the remaining portions of flexible elements 24 or 201 from another plastic material.

Based on the use of main strand 150 and secondary strand 152, tether 12 may be constructed as a relatively compact folded member useful with a number of airbags of various thickness. More specifically, if a relatively small airbag is to be deployed, only fourth strand 204 will separate during deployment while the remaining strands restrict the movement of component 20 relative to the vehicle. If a relatively large airbag, such as a side air curtain is deployed, each of secondary strand 152′, third strand 202 and fourth strand 204 may separate to increase the size of the opening through which the side air curtain travels. Main strand 150′ remains intact to arrest the motion of component 20 after the side curtain has been deployed. Based on the above description, one skilled in the art will appreciate that part proliferation of flexible element 24 and flexible element 201 may be greatly reduced because fastener assembly 10 may be fitted with a common tether for a variety of airbag applications.

After airbag deployment has completed and at least strand 150 arrests movement of component 20, second releasable connection 147 is designed to be released to allow complete separation of component 20 and panel 16 to allow repair of the component part. Third releasable connection 148 separates tether 12 from clip 14. Third releasable connection 148 is disconnected by either applying sufficient force in a direction opposite to the insertion direction or by manual deflection of deflectable tab 88 which allows clip 14 to be slidably disengaged past the end of engagement member 69. The fourth releasable connection 149 is the strongest connection and is generally intended to be a permanent connection, because it may not be readily accessible after installation, and therefore requires manual deflection of the deflectable wings 104, 126, and 128 prior to removal of clip 14 from panel 16.

Material for each of the tethers 12 and 200 is preferably a polymeric material and in one preferred embodiment is a nylon 6,6 material such as Zytel® ST801AHS made by DuPont. According to one preferred embodiment, material for clip 14 is a spring steel material conforming to SAE 1050.

Fastener assemblies of the present invention offer several advantages. By providing multiple releasable connections, each having an individual joint strength which can be configured in ascending or sequential order, events such as an airbag deployment can be accommodated while preventing component parts such as trim panels from completely separating from the vehicle body panel. Movement of the trim panels may be controlled during airbag deployment through the use of a tether having at least one frangible strand in parallel with a non-frangible strand.

The description provided is merely exemplary in nature and, thus, variations are intended to be within the scope of the disclosure. For example, as few as two opposed deflectable wings can be used, or a greater number than three deflectable wings can be used for clip 14. Flexible element 24 can be created as a separate part and connected between connector 30 and engagement member 69, which allows connector 30 and engagement member 69 to be separately created and/or made using different materials to differentiate the releasable connection strength(s). Clip 14 may be formed from a composite or polymeric material. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.

Claims

1. A releasable fastener, comprising:

a clip adapted to be coupled to a first member; and

a tether having a first end releasably coupled to the clip, a second end adapted to be coupled to a second member that is moveable relative to the first member and a flexible member having first and second strands interconnecting the first and second ends of the tether, wherein the second strand is frangible.

2. The fastener of claim 1 further including third and fourth strands positioned in parallel with the first and second strands, wherein the second, third and fourth strands are constructed to sequentially separate under tensile load.

3. The fastener of claim 2 wherein the first, second, third and fourth strands each have a different length.

4. The fastener of claim 3 wherein one of the second, third and fourth strands has a locally reduced cross-sectional size.

5. The fastener of claim 4 wherein one of the second, third and fourth strands separates at a location proximate the reduced cross-sectional size.

6. The fastener of claim 1 wherein one end of the tether includes a pin and the other end includes a receptacle in receipt of the pin, wherein the pin is released from engagement with the receptacle prior to separating the second strand.

7. The fastener of claim 6 wherein the clip includes a channel in slidable receipt of the first end of the tether.

8. The fastener of claim 7 wherein the first end includes a deflectable tab retaining the first end to the clip.

9. The fastener of claim 1 wherein the second strand is adapted to separate upon application of a tensile force provided by the second member moving relative to the first member.

10. The fastener of claim 9 wherein the first strand is adapted to not separate and restrict movement of the second member relative to the first member.

11. The fastener of claim 1 wherein the first strand is adapted to maintain the interconnection between the first and second members after the second strand separates.

12. The fastener of claim 1 wherein the second strand is shorter than the first strand.

13. The fastener of claim 1 wherein the second strand is positioned in parallel with the first strand.

14. The fastener of claim 1 wherein the second strand has a recess formed therein to reduce a cross-sectional size of the second strand at the recess location.

15. A releasable fastener, comprising:

a first connector having a male pin;

a second connector flexibly tethered to the first connector, the second connector having a receptacle and at least one biasing element operable to releasably engage the male pin; and

a clip releasably engageable with the second connector, wherein the flexible tether includes first and second strands, each strand having one end proximate to the first connector and an opposite end proximate to the second connector, wherein the second strand is separable under a predetermined tensile load, the first strand remaining interconnecting the first and second connectors when subject to the predetermined tensile load.

16. The fastener of claim 15 wherein the second strand is positioned in parallel with the first strand.

17. The fastener of claim 16 wherein the clip further comprises a plurality of deflectable wings.

18. The fastener of claim 17 wherein the plurality of deflectable wings comprises a first, a second and a third deflectable wing, the first deflectable wing opposing both the second and the third deflectable wings.

19. The fastener of claim 15 further including third and fourth strands positioned in parallel with the first and second strands, wherein the second, third and fourth strands are constructed to sequentially separate under the tensile load.

20. The fastener of claim 19 wherein the first, second, third and fourth strands each have a different length.

21. The fastener of claim 20 wherein one of the second, third and fourth strands has a locally reduced cross-sectional size.

22. The fastener of claim 15 wherein the second connector further comprises a deflectable tab operable to releasably engage the clip, wherein the deflectable tab is elastically deflectable to receive the clip and returns by spring force to retain the clip.

23. The fastener of claim 15 wherein the first connector includes a hooked end adapted to releasably connect to a first component of a vehicle and wherein the clip is adapted to releasably connect to a second component of a vehicle.

24. A method of manufacturing a releasable fastener, comprising:

releasably coupling a first end of a tether to a first component;

coupling a clip to a second component;

releasably coupling a second end of the tether to the clip;

releasably coupling the first end of the tether to the second end of the tether;

interconnecting the first tether end and the second tether end with a flexible member having a first strand and a second strand; and

separating the second strand upon relative movement between the first and second components.

25. The method of claim 24 maintaining an interconnection between the first and second components with the first strand after the second strand separates.