WO2014109913A1

WO2014109913A1 - Two-stage fastener assembly

Info

Publication number: WO2014109913A1
Application number: PCT/US2013/077814
Authority: WO
Inventors: Michelle E. BOZINOVSKI; Logan J. BRENNEKE
Original assignee: Illinois Tool Works Inc.
Priority date: 2013-01-11
Filing date: 2013-12-26
Publication date: 2014-07-17

Abstract

An improved fastener assembly for securing a panel or other overlying structure to a substructure. The fastener assembly includes an insertable clip member having an upper platform surface and a shaft which extends away from the upper platform and which supports fastener retaining elements. A flanged collar is adapted to receive the shaft of the insertable clip member in pass through relation. The clip and the flanged collar include cooperating spring latch features adapted to securely retain the clip in at an intermediate pre-assembly position within the flanged collar.

Description

TWO-STAGE FASTENER ASSEMBLY

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This non-provisional application claims the benefit of, and priority from, United States Provisional Application 61/751,311 filed January 11, 2013. The contents of such provisional application and all other patent documents referenced in this application are hereby incorporated by reference in their entirety as if fully set forth herein.

TECHNICAL FIELD

[0002] The present disclosure relates generally to fasteners used as intermediate connectors between a first component and a second component disposed in juxtaposed relation to one another. More particularly, the present disclosure relates to a push-through fastener assembly including a collar adapted to operatively engage a structure such as a trim piece, doghouse connector or the like and an insertable clip adapted for staged, press-fit insertion through the collar and into an access opening of an underlying substructure. The clip is adapted for retention in substantially stable relation at the collar in a partial insertion, pre-assembly condition prior to final insertion through the collar and into the access opening.

BACKGROUND OF THE DISCLOSURE

[0003] It is known to use snap-in fasteners to connect substructures such as metal panels and the like in opposing relation to overlying structures such as molding, surface trim and the like. A number of such prior connection devices and techniques are known and disclosed in the art. Such prior fasteners may be formed of plastic or other suitable material and may include a "W" base clip or other snap-in element that is inserted into an acceptance opening in a substructure such as sheet metal forming a structural portion of a vehicle or the like. Such known fasteners may also include an integral head portion which may be operatively mounted at the overlying structure. Such prior plastic fasteners may be constructed and arranged to be driven into a bore formed in the substructure at relatively low pressures such that special tools are not required to install the fastener. Such prior fasteners may be passed entirely through the part that is to be secured to the substructure or may form a "blind" connection wherein the head portion is inserted and retained in a doghouse structure or the like operatively connected at the undersurface of the overlying structure.

[0004] As will be appreciated by those of skill in the art, the molding or other parts with which the fasteners are used may be fabricated at locations remote from the location where the final assembly between the overlying structure and the substructure takes place. Thus, in some instances, it may be desirable to pre-assemble the fasteners with the overlying structure for subsequent shipment to the final assembly location. When such pre-assembly procedures are used, the overlying structure may simply be removed from the container in which it was shipped, positioned appropriately with regard to the substructure, and installed by inserting the shafts of the fasteners into appropriate bores in the substructure such that retaining structures on the shafts of the fasteners can retain the fasteners in the bores of the substructure.

[0005] In some environments of use involving relatively rigid parts, it may be difficult to install groups of fasteners that are not directly aligned with one another. That is, where the axis of the fasteners are not all parallel to one another. This may occur when the substructure is non- planar, such that the fasteners entering the substructure are oriented at different angles to one another such that they cannot all be pressed into receiving openings simultaneously. By way of example only, and not limitation, one such environment of use may be the attachment of a relatively rigid rocker panel to the frame of an automobile. In these cases, it may be desirable to utilize staged insertion fasteners that can be preassembled to the overlying structure at an intermediate insertion condition, and which then may be subsequently fully inserted into the substructure openings.

[0006] By way of example only, and not limitation, US Patent 6,659,701 to Risdale

(incorporated by reference) discloses a staged fastener insertion procedure using a fastener construction having a body or clip portion and a flanged head that are resiliently connected by hinging legs to permit relative movement upon the application of adequate compression forces to fold the legs. While such a structure is useful in a number of environments, the flexible hinging leg construction may give rise to additional complexity in terms of material selection, molding procedures and use. Accordingly, a staged insertion fastener in accordance with the present disclosure which avoids the need for hinging connection elements may provide a useful advantage over prior constructions while still permitting the same staged insertion procedure to be used.

SUMMARY OF THE DISCLOSURE

[0007] The present disclosure provides advantages and alternatives over the prior art by providing an improved fastener assembly for securing a panel or other overlying structure to a substructure. The fastener assembly includes an insertable clip member having an upper platform and a shaft which extends away from the platform and which supports fastener retaining elements. The fastener assembly further includes a collar having a pair of spaced-apart flanges and an interior channel adapted to receive the shaft of the insertable clip member in pass through relation. The clip member and the flanged collar include cooperating spring latch features adapted to securely retain the clip at an intermediate insertion condition within the flanged collar. The intermediate latched condition may be overcome by application of further insertion force and the shaft may be fully inserted through the collar and into retaining engagement with the substructure. The clip member and collar may be formed separately or may be molded as part of a unitary structure. [0008] It is to be understood that a fastener assembly consistent with the present disclosure is well adapted for pre-assembly with a panel body, dog-house connector or other overlying structure in the same manner as disclosed in U.S. Patent 6,659,701 such that in the pre- assembled condition, the flanges of the collar are positioned on opposing sides of the panel. The fastener assembly may be aligned with other fasteners pre-assembled with the panel or may be pre-assembled out of alignment with one or more of the remaining fasteners.

[0009] In accordance with one exemplary aspect, the present disclosure provides a fastener assembly adapted to secure a panel structure to a substructure. The fastener assembly includes a collar having a first flange and a second flange connected in longitudinal spaced-apart relation by a channel member having a bore formed longitudinally therethrough. The bore defines a channel extending completely across the collar in transverse orientation to the flanges. The channel member is adapted for receipt within the panel structure with the panel structure disposed between the flanges. The first flange includes a pair of resilient tab elements at opposing edges of the bore and projecting towards the interior of the bore. The fastener assembly further includes a clip member including a platform, a shaft extending away from the underside of the platform, and resilient retaining elements. The shaft includes a pair of lateral edges, each including a lower detent and an upper detent in spaced apart relation. The lower detent and the upper detent each project outwardly away from the shaft by a distance so as to be in overlapping relation with the tab elements when the clip member is inserted into the bore. Upon application of an initial driving force to the shaft during insertion of the shaft into the bore, the tab elements will be deflected by the lower detents and will snap behind the lower detents to define a substantially stable latched relation with the clip member held within the collar to define a pre- assembly condition. Upon application of a subsequent second driving force to the shaft, the tab elements will be deflected by the upper detents and will snap behind the upper detents during insertion of the retaining elements into an acceptance opening in the substructure. [0010] A method of establishing a connection using a fastener consistent with the present disclosure is also provided. Other exemplary aspects and features will become apparent upon review of the following detailed description of potentially preferred embodiments and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 is a schematic assembly view of an exemplary two-piece fastener assembly consistent with the present disclosure;

[0012] FIG. 2 is a schematic perspective view illustrating the fastener assembly of FIG. 1 with the insertable clip member held in an intermediate latched condition within the collar;

[0013] FIG. 3 is a side view illustrating the intermediate latched condition taken generally along line 3-3 in FIG. 2;

[0014] FIG. 4 is a schematic cross-sectional view taken generally along line 4-4 in FIG. 3 illustrating the exemplary fastener assembly of FIG. 1 in the intermediate latched condition;

[0015] FIG. 5 is an enhanced schematic view illustrating the intermediate latching relation a fastener assembly consistent with the present disclosure;

[0016] FIG. 6 is an expanded perspective surface view illustrating the intermediate latchinj relation in a fastener assembly consistent with the present disclosure;

[0017] FIG. 7 is a view similar to FIG. 3 illustrating the exemplary fastener assembly in a fully inserted condition; and [0018] FIG. 8 is an elevation perspective view illustrating an alternative construction for a fastener assembly consistent with the present disclosure wherein the clip and the collar are molded as a unitary construction.

[0019] Before the exemplary embodiments of the disclosure are explained in detail, it is to be understood that the disclosure is in no way limited in its application or construction to the details and the arrangements of the components set forth in the following description or illustrated in the drawings. Rather, the disclosure is capable of other embodiments and being practiced or being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein are for purposes of description only and should not be regarded as limiting. The use herein of terms such as "including" and "comprising" and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Reference will now be made to the drawings wherein to the extent possible, like elements are designated by like reference numerals in the various views. Referring jointly to FIGS. 1 and 7, a fastener assembly 10 consistent with the present disclosure may be constructed and arranged to be pre-assembled with a panel structure 12 shown in phantom such as trim molding, dog house connector or the like defining an overlying structure for eventual attachment to a substructure 14 (FIG. 6). In this regard, it is to be understood that the term "panel structure" may refer to a panel itself as well as to any intermediate connection element such as a dog house connector or the like which forms an operative connection to the panel. Moreover, the panel is not required to be planar. By way of example only, and not limitation, in one environment of use the panel structure 12 may be a dog house connector at the underside of the rocker panel of an automobile and the substructure 14 may be a portion of the vehicle frame. However, it is to be understood that a fastener assembly 10 consistent with the present disclosure may likewise be used in other suitable automotive and non-automotive environments as may be desired.

[0021] As best seen in FIG. 1, in the illustrated exemplary construction, the fastener assembly 10 includes an insertable clip member 16 of "W" base construction. In the illustrated exemplary construction, the clip member 16 includes a platform 18 defining a proximal force application surface for use in pressing the clip member 16 into place in a manner as will be described further hereinafter. As shown, a shaft 24 projects downwardly away from the underside of the platform defining a travel axis 26 for the clip member 16 when force is applied against the platform 18. As shown, in the exemplary construction, the shaft 24 may be substantially rectangular in cross section. However, other cross-sectional geometries may likewise be used if desired.

[0022] In the illustrated exemplary construction, resilient wing elements 28 defining fastener retention members extend upwardly in angled relation away from the distal end of the shaft 24 in substantially opposing relation to the broad faces of the shaft 24. As will be readily understood by those of skill in the art, the wing elements 28 are adapted to flex inwardly towards the shaft 24 during insertion through an acceptance opening 30 in the substructure 14 (FIG. 7). In the exemplary construction, each of the wing elements 28 incorporates an outer face having a dogleg configuration facing generally outwardly away from the shaft 24. In this regard, in the illustrated construction, the outer face of each wing element 28 includes a proximal face surface 32 extending in upward angled relation away from the travel axis 26 to an elbow 35. A distal face surface 34 defining a panel engagement surface extends away from the elbow 35 in upward angled relation back towards the travel axis 26 until ultimately terminating at the free tip 36 of the wing element thereby establishing the outer surface dogleg profile. In accordance with the preferred construction, the wing elements 28 may be slightly narrower than the opposing surface of the shaft 24. Thus, lateral edges of the shaft 24 may be disposed outboard from the wing elements 28. [0023] As shown, structural ribs 40 may extend between the shaft 24 and the underside of the platform at positions radially outboard from the shaft. In this arrangement, a portion of the platform 18 will define a platform lip 42 disposed outboard from the structural ribs 40.

[0024] As illustrated, in the exemplary construction pairs of molded-in detents are disposed on two opposing, relatively narrow lateral sides of the shaft 24. More specifically, on each of the opposing lateral sides, there is provided a first or lower detent 44 and a second or upper detent 46. As shown, in the exemplary construction the detents project outwardly from the shaft 24 in a direction substantially perpendicular to the flexing path of the wing elements 28 when the wing elements are compressed. The lower detent 44 and the upper detent 46 are at different elevations in spaced apart relation to one another to define an indention zone therebetween. As best seen in FIG. 4, the corresponding lower detents 44 on each side of the shaft 24 may have substantially equivalent constructions and may be positioned at substantially equivalent elevations. Likewise, the corresponding upper detents 46 on each side of the shaft 24 may have substantially equivalent constructions and may be positioned at substantially equivalent elevations. However, the configurations and/or elevations of the detents on opposing sides also may be different if desired.

[0025] In the exemplary construction, the lower detents 44 each may include an angled lower surface 50 and a substantially flat upper surface 52. The upper detents 46 each may include a substantially flat or slightly angled lower surface 54 and an angled upper surface 56. As will be described further hereinafter the lower and upper detents 44, 46 may cooperatively engage a complementary spring latch member adapted to hold the clip member in an intermediate pre- assembly position prior to insertion into the substructure 14.

[0026] Referring again to FIGS. 1-3, the exemplary fastener assembly includes a collar 60 adapted to receive and retain the clip member 16. The collar 60 includes a pair of offset flanges 62 that are spaced apart and connected by a hollow channel member 64 defining a through-bore 66 comprising a slotted passageway extending entirely through the collar member 60. The exterior surface of the channel member 64 may be of any suitable shape but is in a preferred embodiment of generally rectangular shape. The flanges 62 are generally parallel to one another and are spaced apart by an offset distance dictated by the thickness of the panel structure 12. In this regard, the offset distance may be substantially equivalent to or greater than the thickness of the panel structure 12.

[0027] As best seen through reference to FIG. 2, during pre-assembly the collar member 60 may be inserted into a slot 68 or other opening in the panel structure 12. In this regard, the slot 68 may be formed directly into the main body of the panel structure 12, such as at the edge of a large plastic panel, or may be formed as part of an operatively attached doghouse connector or the like as will be well known to those of skill in the art.

[0028] As best seen through joint reference to FIGS. 4-7, at the upper surface of the collar member 60, opposing perimeter edges of the through-bore 66 may each include a cut-out 70 (only one shown) of toothed construction adapted to receive the edges of the shaft 24 in guided, sliding relation during insertion. In this regard, the width of the cut-outs 70 may be substantially equivalent to or slightly larger than the thickness dimension of the sides of the shaft 24. Thus, the cut-outs 70 may assist in guiding the clip member 16 into aligned position within the collar member 60 during insertion. As shown, in the exemplary construction, each of the cut-outs 70 may include a resilient tab 72 defining a leaf spring bordered on each side by lateral indents 74. In the illustrated arrangement, the tabs have lengths slightly less than the depth of the cut-outs such that free ends of the tabs are positioned in withdrawn relation to the edges of the bore adjacent to the cut-outs 70. As will be appreciated, in this arrangement, the tabs 72 may deflect and recover in a vertical direction during the insertion process while also permitting the cut-outs 70 to receive and slidingly guide the edges of the shaft 24 during insertion. [0029] As bet seen in FIGS. 4 and 5, the cooperative engagement between the tabs 72 and the detents 44, 46 during insertion may be used to establish a latched intermediate insertion condition between the clip member 16 and the collar member 60 for use during shipment and pre-assembly. In this regard, during the pre-assembly process, the clip member 16 may be inserted into the through-bore 66 with the edges of the shaft 24 guided between the lateral sides of the cut-outs 70. This insertion may take place either before or after engagement between the collar member 60 and the panel structure 12. The lower detents 44 and the upper detents each project outwardly away from the edges of the shaft 24 by a distance so as to be in overlapping relation with the opposing tabs 72 when the clip member 16 is inserted.

[0030] During the insertion process, the lower detents 44 will first encounter the tabs 72. As insertion pressure is applied, the resilient tab elements 72 will deflect downwardly as they engage the angled lower surfaces 50 and will then spring behind corresponding upper surfaces 52. In this intermediate insertion condition, the tab element 72 will be held in latched relation in the indentation between the upper and lower detents. As will be appreciated, in this intermediate condition, the clip member 16 is held in substantially secure relation to the collar member and either extraction or further advancement will require substantial additional force application. In this regard, the slope of the angled lower surface 50 on the lower detent 44 may be substantially steeper than the slope of the angled lower surface 54 on the upper detent 46. The reduced slope at the bottom of the upper detent 46 relative to the lower detent 44 results in a greater force requirement to move the upper detent 46 past the tab element 72. This additional force requirement may aid a user in preventing unintended insertion beyond the intermediate latched position until such insertion is intended.

[0031] As best seen in FIGS. 3-5, in the intermediate latched condition for pre-assembly, the distal end of the clip member 16 is preferably disposed entirely within the interior of the through- bore 66 at an elevation such that it does not project outwardly beyond the outer surface of the lower flange. Thus, the tip of the clip member 16 may be spaced apart from the substructure 14 during alignment with the acceptance opening 30. Of course, the elevation of the detents 44, 46 also may be set to permit a portion of the clip member to project slightly beyond the underside of the collar member 60 if desired.

[0032] As best seen through joint reference to FIGS. 3-7, when connection to the

substructure is desired following pre-assembly, a driving force may be applied against the platform 18 of the clip member 16 so as to move the upper detent 46 past the tab element 72 and to drive the shaft 24 further into the through-bore 66 and subsequently into engagement with the acceptance opening 30 in the substructure 14. As best seen in FIG. 7, in the illustrated exemplary construction, insertion of the shaft 24 may continue until the platform lip 42 encounters the upper flange 62 of the collar member 60 in contacting relation and the wing elements 28 form a fastening engagement with the substructure 14 such that the fastener assembly with the operatively connected panel structure 12 is held in place. As will be appreciated, in the final installed position the upper portion of the shaft 24 remains in sliding guided relation within the cut-outs 70. Thus, there is no substantial obstruction to outward movement of the shaft 24 except as provided by the wing elements 28.

[0033] In accordance with one exemplary practice, the clip member 16 and the collar member 60 may be formed separately as unitary structures by injection molding or other suitable techniques using suitable materials such as Nylon 6.6, polyester, acetal resin or the like with sufficient rigidity and strength to avoid undesired failure following insertion. The materials forming the clip member 16 and the collar 60 may be either the same or different. Thus, while a single material may be used, two or more materials may also be used.

[0034] It is also contemplated that the clip member and the collar member may be formed as a single piece by injection molding or other suitable techniques using suitable materials such as Nylon 6.6, polyester, acetal resin or the like with sufficient rigidity and strength to avoid undesired failure following insertion. By way of example only, and not limitation, FIG. 8 illustrates a one-piece molded fastener assembly 110 consistent with the present disclosure and wherein elements previously described are designated by like reference numerals within a 100 series.

[0035] The exemplary one-piece molded fastener assembly 110 of FIG. 8 is substantially identical to the two-piece structure described previously. However, in this embodiment, the clip element 116 is mounted in aligned orientation to the through-bore 166 on molded- in frangible supports 185 extending between the wing elements 128 and the lateral edges of the through-bore 166. Using this construction, the clip member 16 is pre-aligned and may be pressed inwardly into the through-bore 166 causing the frangible supports to fracture harmlessly without obstruction to the insertion process. As will be appreciated, such a one-piece structure will reduce the number of individual components and may reduce complexity. The possibility of error in matching the proper clip member to the proper collar is also eliminated.

[0036] Of course, variations and modifications of the foregoing are within the scope of the present disclosure. Thus, it is to be understood that the disclosure disclosed and defined herein extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and/or drawings. All of these different combinations constitute various alternative aspects of the present disclosure. The embodiments described herein explain the best modes known for practicing the disclosure and will enable others skilled in the art to utilize the disclosure. The claims are to be construed to include alternative embodiments and equivalents to the extent permitted by the prior art.

[0037] Various features of the disclosure are set forth in the following claims.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. A fastener assembly adapted to secure a panel structure to a substructure, the fastener assembly comprising:

a collar comprising a first flange and a second flange connected in longitudinal spaced- apart relation by a channel member having a bore formed longitudinally therethrough, the bore defining a channel extending completely across the collar in transverse orientation to the flanges, the channel member being adapted for receipt within the panel structure with the panel structure disposed between the flanges, wherein the first flange includes a pair of resilient tab elements defining spring latches disposed at opposing edges of the bore and projecting towards the interior of the bore; and

a clip member including a platform, a shaft extending away from the underside of the platform, and a pair of resilient retaining elements, the shaft including a pair of lateral edges, the lateral edges each including a lower detent and an upper detent in spaced apart relation, the lower detent and the upper detent each projecting outwardly away from the shaft by a distance so as to be in overlapping relation with the tab elements when the clip member is inserted into the bore, such that upon application of an initial driving force to the shaft during insertion of the shaft into the bore, the tab elements will be deflected by the lower detents and will snap behind the lower detents to define a substantially stable operative latched connected relation with the clip member held within the collar, and wherein upon application of a subsequent second driving force to the shaft, the tab elements will be deflected by the upper detents and will snap behind the upper detents during insertion of the retaining elements into an acceptance opening in the substructure.

2. The fastener assembly as recited in Claim 1, wherein the retaining elements comprise a pair of resilient wings extending in upward angled relation away from an insertion axis defined by the shaft.

3. The fastener assembly as recited in Claim 2, wherein the wings each have an outer surface of substantially dog leg profile.

4. The fastener assembly as recited in Claim 1, wherein the panel structure is a dog house connection.

5. The fastener assembly as recited in Claim 1, wherein the shaft is substantially rectangular in cross-section.

6. The fastener assembly as recited in Claim 5, wherein the resilient tab elements are disposed within a pair of cut-outs at the opposing edges of the bore, and free ends of the tab elements are positioned in withdrawn relation relative to the edges of the bore adjacent to the cut-outs.

7. The fastener assembly as recited in Claim 6, wherein the lateral edges of the shaft are adapted for receipt in sliding, guided relation within the cut-outs during insertion of the shaft into the bore.

8. The fastener assembly as recited in Claim 7, wherein the underside of each of the lower detents is sloped and the underside of each of the upper detents is sloped, the slope of the underside of the lower detents being steeper than the slope of the underside of the upper detents.

9. The fastener assembly as recited in Claim 8, wherein the underside of each of the tab elements is sloped.

10. The fastener assembly as recited in Claim 9, wherein the upper face of each of the lower detents is oriented substantially perpendicular to an insertion axis defined by the shaft.

11. The fastener assembly as recited in Claim 1, wherein the collar and the clip member are separately molded components.

12. The fastener assembly as recited in Claim 1, wherein the collar and the clip member are parts of a unitary molded construction.

13. The fastener assembly as recited in Claim 12, wherein prior to insertion into the bore, the clip member is supported in substantially aligned relation to the bore on molded-in frangible supports extending away from edges of the bore.

14. A fastener assembly adapted to secure a panel structure to a substructure, the fastener assembly comprising:

a collar comprising a first flange and a second flange connected in longitudinal spaced- apart relation by a channel member having a bore formed longitudinally therethrough, the bore defining a channel extending completely across the collar in substantially perpendicular orientation to the flanges, the channel member being adapted for receipt within the panel structure with the panel structure disposed between the flanges, wherein the first flange includes a pair of cut-outs disposed at opposing edges of the bore, the cut-outs each including a resilient tab element defining a spring latch projecting towards the interior of the bore, the tab elements being bordered by lateral indents, the tab elements having operative lengths such that free ends of the tab elements are positioned in withdrawn relation relative to the edges of the bore adjacent to the cut-outs; and

a clip member including a platform, a shaft extending away from the underside of the platform in substantially perpendicular relation to the platform, and a pair of resilient retaining elements comprising wings extending in upward angled relation away from an insertion axis defined by the shaft, the shaft including a pair of lateral edges adapted for receipt in guided relation within the cut-outs, the lateral edges each including a lower detent and an upper detent in spaced apart relation, wherein the underside of each of the lower detents is sloped, the lower detent and the upper detent each projecting outwardly away from the shaft by a distance so as to be in overlapping relation with the tab elements when the clip member is inserted into the bore with the lateral edges in sliding relation in the cut-outs, such that upon application of an initial driving force to the shaft during insertion of the shaft into the bore, the tab elements will be deflected by the lower detents and will snap behind the lower detents to define a substantially stable operative latched connected relation with the clip member held within the collar, and wherein upon application of a subsequent second driving force to the shaft, the tab elements will be deflected by the upper detents and will snap behind the upper detents during insertion of the retaining elements beyond the collar and into an acceptance opening in the substructure.

15. The fastener assembly as recited in Claim 14, wherein the panel structure is a dog house connection.

16. The fastener assembly as recited in Claim 14, wherein the shaft is substantially rectangular in cross-section.

17. The fastener assembly as recited in Claim 7, wherein the underside of each of the upper detents is sloped, the slope of the underside of the lower detents being steeper than the slope of the underside of the upper detents.

18. The fastener assembly as recited in Claim 17, wherein the underside of each of the tab elements is sloped and wherein the upper face of each of the lower detents is oriented substantially perpendicular to an insertion axis defined by the shaft.

19. A fastener assembly adapted to secure a panel structure to a substructure, the fastener assembly comprising: a collar comprising a first flange and a second flange connected in longitudinal spaced- apart relation by a channel member having a bore formed longitudinally therethrough, the bore defining a channel extending completely across the collar in substantially perpendicular orientation to the flanges, the channel member being adapted for receipt within the panel structure with the panel structure disposed between the flanges, wherein the first flange includes a pair of cut-outs disposed at opposing edges of the bore, the cut-outs each including a resilient tab element defining a spring latch projecting towards the interior of the bore, the tab elements being bordered by lateral indents, the tab elements having operative lengths less than the depth of the lateral indents such that free ends of the tab elements are positioned in withdrawn relation relative to the edges of the bore adjacent to the cut-outs; and

a clip member including a platform, a shaft of substantially rectangular cross-section extending away from the underside of the platform in substantially perpendicular relation to the platform, and a pair of resilient retaining elements comprising wings extending in upward angled relation away from an insertion axis defined by the shaft, the shaft including a pair of lateral edges adapted for receipt in guided relation within the cut-outs, the lateral edges each including a lower detent and an upper detent in spaced apart relation, wherein the underside of each of the lower detents is sloped, the underside each of the upper detents is sloped, and the underside of each of the tab elements is sloped, the slope of the underside of the lower detents being steeper than the slope of the underside of the lower detents, the lower detent and the upper detent each projecting outwardly away from the shaft by a distance so as to be in overlapping relation with the tab element within the corresponding cut-out when the lateral edges are within the cut-outs such that upon application of an initial driving force to the shaft during insertion of the shaft into the bore, the tab elements will be deflected by the lower detents and will snap behind the lower detents to define a substantially stable operative latched connected relation with the clip member held within the collar at an elevation such that a distal tip of the clip member does not extend beyond the collar, and wherein upon application of a subsequent second driving force to the shaft, the tab elements will be deflected by the upper detents and will snap behind the upper detents during insertion of the retaining elements beyond the collar and into an acceptance opening in the substructure.

20. The fastener assembly as recited in Claim 19, wherein the collar and the clip member are parts of a unitary molded construction and wherein prior to insertion into the bore, the clip member is supported in substantially aligned relation to the bore on molded-in frangible supports extending away from edges of the bore.