FIELD 
     The present disclosure relates to automobile fastener clips used to join components to a vehicle body. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     For automotive applications, fasteners are used to join trim or panel members to sections or metal body portions of the automobile. The requirements for these fasteners are that they be insertable into apertures of the automobile and meet requirements to both retain the component as well as provide a minimum pullout retention force such that the component is retained under given load conditions but can be removed without damaging the component. Common fastener designs include directly opposed flexible wings which deflect inwardly upon insertion of the fastener and expand by spring force to hold the fastener within an aperture such as a slot in the automobile. 
     A drawback of commonly used fasteners occurs for certain applications, including fasteners used to mount trim or instrument panels, or for trim components which cover air bags. In the first instance, it is common that access to the space behind the trim or instrument panel is desired, however removal of the entire trim piece or panel may be undesirable due to weight or realignment concerns. For trim member applications covering an air bag, deployment of the air bag often displaces the trim component, however, it is undesirable for the trim component to freely disassociate from the body portion of the automobile. To prevent disassociation, fasteners have been created having two-part assemblies, with one part connected to the vehicle body and the second part connected to the trim component or panel member. These fastener designs commonly include a tether which allows the trim or panel component to displace while preventing disassociation from the first part and therefore from the vehicle body. A drawback of these fastener designs is the tether only loosely retains the trim or panel member which can still result in realignment problems, or inadvertent disconnection of electrical connectors, or the like. 
     SUMMARY 
     According to several embodiments of the present invention, a fastener system for use with an air bag has a fastener including a rounded base having a flat portion, and first and second arms oriented transverse to the flat portion. A first set of vehicle panel engagement devices is connected to the fastener proximate to the rounded base. A second set of vehicle panel engagement devices is connected to the fastener spatially separated from both the first set of vehicle panel engagement devices and the rounded base. A vehicle component has a dog-house homogenously connected thereto. The rounded base is slidably received within and engaged with the dog-house to releasably connect the fastener to the vehicle component. The vehicle component is adapted to be displaceable upon deployment of an air bag. 
     According to further embodiments, a fastener assembly includes a first member having first and second arms each including first and second elongated slots. A second member is slidingly engaged with the first member, the second member having first and second body portions each including first and second tabs extending toward an opposite one of the first and second body portions. A plurality of dimples are created on each of the first and second body portions. The plurality of dimples of the first body portion extend into the first and second elongated slots of the first arm in a first engaged position of the first and second members, and the plurality of dimples of the second body portion extend into the first and second elongated slots of the second arm in the first engaged position. The first and second tabs of the first body portion are slidingly positioned within the first and second elongated slots of the first arm, and the first and second tabs of the second body portion are slidingly positioned within the first and second elongated slots of the second arm. 
     According to further embodiments, a telescoped second engaged position of the fastener assembly has the first and second tabs of the first body portion each in contact with an end wall of the first and second elongated slots of the first arm, and the first and second tabs of the second body portion each in contact with an end wall of the first and second elongated slots of the second arm. The telescoped second position also has the plurality of dimples of each of the first and second body portions displaced out of the first and second elongated slots of both the first and second members. 
     According to further embodiments, a fastener system includes a first member having a rounded base having a flat portion and first and second arms oriented transverse to the flat portion. The first and second arms each include first and second elongated slots. A second member is slidingly engaged with the first member. The second member has first and second body portions each including first and second tabs extending toward an opposite one of the first and second body portions. Each of the first and second tabs are slidingly received in one of the first or second slots allowing the second member to slide in a first direction away from the rounded base. A dog-house is homogenously connected to a polymeric member. The dog-house receives and engages the rounded base in a second direction transverse to the first direction. 
     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. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
         FIG. 1  is front perspective view of a fastener assembly for a two stage, telescoping high retention fastener of the present disclosure; 
         FIG. 2  is front perspective view of a first member of the fastener assembly of  FIG. 1 ; 
         FIG. 3  is a front elevational view of the first member of  FIG. 2 ; 
         FIG. 4  is a side elevational view of the first member of  FIG. 2 ; 
         FIG. 5  is a top plan view of the first member of  FIG. 2 ; 
         FIG. 6  is front perspective view of a second member of the fastener assembly of  FIG. 1 ; 
         FIG. 7  is a front elevational view of the second member of  FIG. 6 ; 
         FIG. 8  is a side elevational view of the second member of  FIG. 6 ; 
         FIG. 9  is a top plan view of the second member of  FIG. 6 ; 
         FIG. 10  is a front elevational view showing a pre-assembled condition of the fastener assembly of  FIG. 1 ; 
         FIG. 11  is a front elevational view of the fastener assembly of  FIG. 1 ; 
         FIG. 12  is a side elevational view of the fastener assembly of  FIG. 1 ; 
         FIG. 13  is a partial cross sectional front perspective view of a dog-house assembly adapted to receive the fastener assembly of  FIG. 1 ; 
         FIG. 14  is a bottom perspective view of the fastener assembly of  FIG. 1 ; 
         FIG. 15  is a partial cross sectional side elevational view of a sub-assembly of the fastener assembly of  FIG. 1  engaged with the dog-house assembly of  FIG. 13 ; 
         FIG. 16  is a partial cross sectional side elevational view of the fastener sub-assembly of  FIG. 15  after engagement with a vehicle body panel; 
         FIG. 17  is a partial cross sectional side elevational view of the fastener subassembly of  FIG. 15  after partial displacement away from the vehicle body panel; 
         FIG. 18  is a partial cross sectional side elevational view of the fastener subassembly of  FIG. 15  after full displacement away from the vehicle body panel; 
         FIG. 19  is a front elevational view of a second embodiment of a fastener of the present disclosure; 
         FIG. 20  is a side elevational view of the fastener of  FIG. 19 ; 
         FIG. 21  is a top plan view of the fastener of  FIG. 19 ; and 
         FIG. 22  is a partial cross sectional side elevational view of an assembly of the fastener of  FIG. 19  to an automotive vehicle panel. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
     Referring to  FIG. 1 , a fastener assembly  10  includes a first member  12  which is releasably and slidably connected to a second member  14 . First member  12  includes a rounded base  16  having curved ends extending from a flat portion and substantially parallel, opposed first and second legs  18 ,  20  extending transversely with respect to the flat portion. First leg  18  includes a first elastically flexible arm  22 . Similarly, second leg  20  includes a second elastically flexible arm  24 . First leg  18  and first elastically flexible arm  22  are oriented as substantially a mirror image configuration of second leg  20  and second elastically flexible arm  24 . First member  12  can be made of a metal such as spring steel, or from other materials including one or more polymeric materials. 
     Second member  14  defines a U-shape and includes first and second body portions  26 ,  28  which are connected by first and second joining bands  30 ,  32 . First and second joining bands  30 ,  32  are homogenous extensions of first and second body portions  26 ,  28 . A first tab  34  and a second tab  36  are homogenous extensions of first body portion  26 . First and second tabs  34 ,  36  are formed by a cutting, piercing, stamping, or similar operation performed on first body portion  26  and bent to extend from first body portion  26  toward second body portion  28 . Second body portion  28  also includes each of a first and second tab  34 ′,  36 ′ which are not clearly visible in this view which are mirror images of first and second tabs  34 ,  36 . First body portion  26  also includes each of a first, second, third, and fourth alignment dimple  38 ,  40 ,  42 ,  44 . First and third alignment dimples  38 ,  42  are coaxially aligned with first tab  34 . Similarly, third and fourth alignment dimples  42 ,  44  are coaxially aligned with second tab  36 . Second body portion  28  also includes each of a corresponding first, second, third, and fourth alignment dimples  38 ′,  40 ′,  42 ′,  44 ′ which are mirror image copies of first, second, third and fourth alignment dimples  38 ,  40 ,  42 ,  44 . Second member  14  can be made of a metal such as spring steel similar to first member  12 , or from other materials including one or more polymeric materials. 
     First body portion  26  further includes a first engagement member  46  which extends to an opposite direction with respect to first and second tabs  34 ,  36 . Similarly, second body portion  28  includes a second engagement member  48  which is a mirror image configuration of first engagement member  46  and similarly extends away from second body portion  28  in an opposite direction with respect to first and second tabs  34 ′,  36 ′. 
     Referring to  FIG. 2 , first member  12  further includes parallel first and second elongated tab receiving slots  50 ,  52 . First and second elongated tab receiving slots  50 ,  52  extend in a direction transverse to rounded base  16  and are each created in first leg  18 . Similarly, second leg  20  includes each of a third and fourth elongated tab receiving slot  54 ,  56  which are mirror image configurations of first and second elongated tab receiving slots  50 ,  52 . The elongated tab receiving slots  50 ,  52 ,  54 ,  56  are closed-ended slots and each include at least an end wall  53 ′,  53 ″,  53 ′″,  53 ″″ and opposed side walls  57 ,  59  respectively. Each of a first and second tab alignment member  58 ,  60  homogenously extend from a free end of first leg  18 . Similarly, each of a third and fourth tab alignment member  62 ,  64  homogenously extend beyond a free end of second leg  20 . First and second tab alignment members  58 ,  60  are oriented at an angle with respect to first leg  18  and bent toward each of a third and fourth tab alignment member  62 ,  64  which each homogenously extend from second leg  20  in a mirror image of first and second tab alignment members  58 ,  60 . 
     Positioned between first and second tab alignment members  58 ,  60  is a first assembly alignment member  66  which homogenously extends from first leg  18  and is commonly angled with respect to first and second tab alignment members  58 ,  60 . Similarly, a second assembly alignment member  68  is positioned between each of third and fourth tab alignment members  62 ,  64  homogenously extending from second leg  20 , and commonly angled with respect to third and fourth alignment members  62 ,  64  toward first assembly alignment member  66 . 
     All of the features shown for first member  12  are created from various punching, stamping, bending, or other similar operations performed on a sheet or plate of material such as spring steel or commonly molded from a polymeric material in a single mold operation. Other metal materials or polymeric materials can be substituted for spring steel for either first member  12  or second member  14 . Spring steel is selected for several embodiments of the present disclosure to provide a spring or bias force tending to retain first and second legs  18 ,  20  in the general configuration shown in  FIG. 2  during installation or subsequent use of fastener assembly  10 . 
     Referring to  FIGS. 3-5 , first member  12  can also include a cavity  70  created between first and second elongated tab receiving slots  50 ,  52  of first leg  18 . Similarly, first member  12  can also include a cavity  70 ′ created in second leg  20  between third and fourth elongated tab receiving slots  54 ,  56 . First member  12  has a first member height “A”, a first member base width “B”, a first member base height “C”, a leg spacing dimension “D”, a flexible arm non-deflected spacing “E”, and a first member length “F”. According to several embodiments, first member height “A” is approximately 27.0 mm, first member base width “B” can be approximately 14.4 mm, first member base height “C” can be approximately 3.2 mm, leg spacing dimension “D” can be approximately 4.4 mm, and first member length “F” can be approximately 24.0 mm. Flexible arm non-deflected spacing “E” is a distance measurable between each of a first flexible arm convex portion  72  and a second flexible arm convex portion  76 . According to several embodiments, flexible arm non-deflected spacing “E” can be approximately 7.8 mm. A first flexible arm concave portion  74  and a second flexible arm concave portion  78  are each created at a free end of first and second flexible arms  22 ,  24 , respectively. 
     Referring to  FIG. 6  and again to  FIG. 2 , each of the first, second, third, and fourth alignment dimples  38 ,  38 ′,  40 ,  40 ′,  42 ,  42 ′,  44 ,  44 ′ are created on outward facing surfaces of first and second body portions  26 ,  28 . A rounded raised surface  80  is therefore created on each of the inward facing surfaces of first and second body portions  26 ,  28  (i.e.: the surfaces between first and second body portions  26 ,  28 ). A diameter “X” of each of the rounded raised surfaces  80  is smaller than a span width of the first, second, third, and fourth elongated tab receiving slots  50 ,  52 ,  54 ,  56  shown and described in reference to  FIG. 2 . Each of the rounded raised surfaces  80  are therefore intended to fit within the elongated tab receiving slots  50 ,  52 ,  54 ,  56  to help prevent rotation of the second member  14  when second member  14  is engaged with first member  12  to create fastener assembly  10  (described in reference to  FIG. 1 ). Each of the first and second engagement members  46 ,  48  also include a first engagement wing  82  and an opposed second engagement wing  84  which extend substantially transverse to a planar surface  85 . A cavity  86 ,  86 ′ is created in each of first and second body portions  26 ,  28  when first tabs  34 ,  34 ′ are created. Similarly, a cavity  88 ,  88 ′ is created in each of first and second body portions  26 ,  28  when second tabs  36 ,  36 ′ are created. 
     Referring to  FIGS. 7-9  and again to  FIG. 1 , second member  14  has a second member width “G” which is substantially equal to first member length “F” described in reference to  FIG. 5 . A second member slot  90  has a second member slot width “H” which allows second member  14  to be slidably received on first member  12  allowing clearance for each of the first and second flexible arms  22 ,  24 . Second member  14  also has a second member height “J”. According to several embodiments, second member width “G” is approximately 24.0 mm, second member slot width “H” is approximately 8.0 mm, and second member height “J” is approximately 25.6 mm. The dimensions provided herein are for example only and can be modified at the discretion of the manufacturer to suit various sizes and geometries of fastener assemblies  10  of the present disclosure. 
     First and second tabs  34 ,  34 ′,  36 ,  36 ′ are positioned proximate to free ends of each of first and second body portions  26 ,  28 . The free ends of first and second body portions  26 ,  28  are separated by a first leg spacing dimension “K”. The first and second joining bands  30 ,  32  define a second leg spacing dimension “L”. According to several embodiments, first leg spacing dimension “K” is equal to or less than second leg spacing dimension “L” so that as second member  14  is engaged with first member  12  a spring or biasing force is created by temporary separation of first and second body portions  26 ,  28  which acts to elastically return first and second body portions  26 ,  28  to the configuration shown in  FIG. 8  when first and second tabs  34 ,  34 ′,  36 ,  36 ′ engage within the elongated tab receiving slots  50 ,  52 ,  54 ,  56  of first member  12  described in reference to  FIG. 2 . In the non-deflected state shown in  FIG. 8 , free ends of first and second engagement members  46 ,  48  are separated by an engagement member spacing dimension “M”. According to several embodiments, first leg spacing dimension “K” is approximately 4.9 mm, second leg spacing dimension “L” is approximately 5.3 mm, and engagement member spacing dimension “M” is approximately 9.3 mm. 
     Referring more specifically to  FIG. 9 , a tab extension dimension “N” of second tab  36  is representative of each of the first and second tabs  34 ,  34 ′,  36 ,  36 ′ such that each of the first and second tabs  34 ,  34 ′,  36 ,  36 ′ extend from first and second body portions  26 ,  28  by tab extension dimension “N”. Both of the first and second engagement members  46 ,  48  have an engagement member width “P”. According to several embodiments, tab extension dimension “N” is approximately 1.5 mm and engagement member width “P” is approximately 7.2 mm. 
     Referring to  FIGS. 10 through 12 , second member  14  is shown aligned with but prior to engagement with first member  12 . Each of the first tabs  34 ,  34 ′, the first alignment dimples  38 ,  38 ′, and the second alignment dimples  40 ,  40 ′ are coaxially aligned along a first alignment axis defined through a center of both first and third elongated tab receiving slots  50 ,  54 . Similarly, second tabs  36 ,  36 ′, third alignment dimples  42 ,  42 ′, and fourth alignment dimples  44 ,  44 ′ are coaxially aligned with a center of second and fourth elongated tab receiving slots  52 ,  56 . As second member  14  is slidingly engaged with first member  12  in an engagement direction “Q”, first and second tabs  34 ,  34 ′ and  36 ,  36 ′ engage with corresponding ones of the first tab alignment member  58  and third tab alignment member  62 , or with second tab alignment member  60  and fourth tab alignment member  64  respectively. 
     Sliding engagement of the first and second tabs  34 ,  34 ′,  36 ,  36 ′ with the tab alignment members  58 ,  60 ,  62 ,  64  elastically deflects first body portion  26  away from second body portion  28  of second member  14  (by bending at first and second joining bands  30 ,  32 ) until by continued engagement in engagement direction “Q” the first and second tabs  34 ,  34 ′,  36 ,  36 ′ engage within the elongated tab receiving slots  50 ,  52 ,  54 ,  56 . Thereafter, each of the first and second tabs  34 ,  34 ′,  36 ,  36 ′ can slide within their respective one of the elongated tab receiving slots  50 ,  52 ,  54 ,  56  allowing second member  14  to telescopically slide with respect to first member  12 . Continued engagement of second member  14  in engagement direction “Q” positions the alignment dimples  38 ,  38 ′,  40 ,  40 ′,  42 ,  42 ′,  44 ,  44 ′ in respective ones of the elongated tab receiving slots  50 ,  52 ,  54 ,  56 . The alignment dimples  38 ,  38 ′,  40 ,  40 ′,  42 ,  42 ′,  44 ,  44 ′ thereafter prevent rotation of second member  14  with respect to first member  12 . When second member  14  is fully engaged with first member  12 , both first and second assembly alignment members  66 ,  68  are positioned proximate to a cavity  97  created between first and second joining bands  30 ,  32 . 
     Referring more specifically to  FIGS. 11 and 12 , in the assembled condition of fastener assembly  10 , first and second engagement members  46 ,  48  are freely deflectable within cavities  70 ,  70 ′. Fastener assembly  10  has a fastener assembly height “R” which according to several embodiments of the present disclosure is approximately 30.6 mm. 
     Referring now to  FIG. 13 , a dog-house  98  can be homogenously connected to a member  99  such as a trim member adapted for installation on an automobile vehicle. Dog-house  98  is created from a polymeric material which can be co-molded with the member  99 . Dog-house  98  includes a first wall  100  and an opposed second wall  102 . A rear wall  103  together with first and second walls  100 ,  102  support an upper wall  104 . A slot  106  is created in upper wall  104  so that dog-house  98  can slidably receive fastener assembly  10  (shown in reference to  FIG. 15 ). A lower wall  108  which is substantially parallel to upper wall  104  provides a beam  110  homogenously extending upwardly as viewed in  FIG. 13  from lower wall  108  and parallel to slot  106 . Beam  110  includes a planar surface  111 . First and second walls  100 ,  102 , rear wall  103 , upper wall  104 , and lower wall  108 , together define a cavity  112 . An engagement tooth  114  is homogeneously created on surface  111  proximate to rear wall  103  and extends upwardly as viewed in  FIG. 13  away from surface  111 . 
     Referring to  FIG. 14  and again to  FIG. 13 , rounded base  16  of first member  12  of fastener assembly  10  includes an elongated slot  116  created in a substantially flat portion  117  of rounded base  16 . An edge face  118  defining a first end of elongated slot  116  is provided to engage with the engagement tooth  114  described in reference to  FIG. 13  when fastener assembly  10  is slidably inserted into cavity  112  of dog-house  98 . The engagement between edge face  118  and engagement tooth  114  provides a positive engagement of fastener assembly  10  within dog-house  98 . 
     Referring to  FIG. 15 , fastener assembly  10  is shown following horizontal installation within cavity  112  of dog-house  98 . In this position, the lower surface of rounded base  16  is in slidable contact with surface  111  of beam  110 . At the same time, an upper surface  120 ,  120 ′ of rounded base  16  is frictionally engaged with a lower surface  122  of upper wall  104 . The remaining portions of fastener assembly  10  extend freely and transversely away from dog-house  98  through slot  106 . 
     Referring to  FIG. 16 , a sub-assembly  123  having fastener assembly  10  engaged with dog-house  98  can be used by inserting fastener assembly  10  starting at second member  14  into a longitudinal slot  124  created in a body panel  126  of an automobile vehicle (not shown). Fastener assembly  10  is inserted in an insertion direction “S” until an upper surface  128  of dog-house  98  contacts body panel  126 . First engagement member  46  and second engagement member  48  both elastically deflect toward each other as they are inserted through longitudinal slot  124  then return to their normal extended positions. Subsequently, first and second flexible arms  22 ,  24  elastically deflect toward each other as first flexible arm convex portion  72  and second flexible arm convex portion  76  pass through longitudinal slot  124 . When body panel  126  is in contact with upper surface  128 , first and second flexible arms  22 ,  24  elastically deflect outwardly until first flexible arm concave portion  74  and second flexible arm concave portion  78  individually contact opposed side walls of longitudinal slot  124 . First flexible arm concave portion  74  and second flexible arm concave portion  78  are each sized (e.g.: depth and length of curvature) to accommodate a plate thickness “T” of body panel  126 . According to several embodiments, plate thickness “T” can range from approximately 0.8 mm to approximately 1.5 mm. This range can be increased or decreased by modifying the geometry of first and second flexible arm concave portions  74 ,  78 . With the sub-assembly  123  of dog-house  98  and fastener assembly  10  in contact with body panel  126 , a pull force “Y” of approximately 50 pounds is required to displace dog-house  98  from body panel  126  by overcoming the biasing and static friction forces created by first and second flexible arm concave portions  74 ,  78 . 
     Referring to  FIG. 17 , when the pull force “Y” of approximately 50 pounds has been achieved, for example by expansion or release of an air bag  130  positioned behind or in contact with member  99 , separation between sub-assembly  123  having dog-house  98  and fastener assembly  10  can occur with dog-house  98  and member  99  moving in a displacement direction “U” with respect to body panel  126 . Displacement in displacement direction “U” continues until body panel  126  contacts first and second engagement members  46 ,  48 . At this time, first member  12  is still in complete engagement with second member  14  such that first and second tabs  34 ,  34 ′,  36 ,  36 ′ are positioned proximate to first and second flexible arms  22 ,  24 . 
     Referring to  FIG. 18 , after body panel  126  contacts first and second engagement members  46 ,  48  further displacement of dog-house  98  in displacement direction “U” causes a sliding displacement between second member  14  and first member  12  with each of the first and second tabs  34 ,  34 ′,  36 ,  36 ′ retained in sliding engagement with the elongated tab receiving slots  50 ,  52 ,  54 ,  56  (not visible in this view) of first and second legs  18 ,  20 . Sliding displacement of first member  12  with respect to second member  14  forces first, second, third, and fourth alignment dimples  38 ,  40 ,  42 ,  44  to displace from the elongated tab receiving slots  50 ,  52 ,  54 ,  56  (not visible in this view). Sliding displacement of first member  12  with respect to second member  14  continues until first and second tabs  34 ,  34 ′,  36 ,  36 ′ contact the end walls  53 ′,  53 ″,  53 ′″,  53 ″″ of the elongated tab receiving slots  50 ,  52 ,  54 ,  56  (not visible in this view). 
     At this time, a clearance dimension “V” is provided between body panel  126  and upper wall  104  of dog-house  98 . According to several embodiments, clearance dimension “V” can be approximately 24.8 mm. Clearance dimension “V” allows manual access to squeeze together first and second body portions  26 ,  28  as well as first and second legs  18 ,  20  with a force to inwardly displace first and second engagement members  46 ,  48  so that first and second engagement members  46 ,  48  are drawn toward each other and can be withdrawn through longitudinal slot  124  of body panel  126  to completely remove fastener assembly  10  and dog-house  98  from body panel  126 . Clearance dimension “V” can also provide for limited access between member  99  and body panel  126 , for example for installation of electrical wires, tubing, and the like. 
     Referring to  FIGS. 19 through 21  and again to  FIG. 1 , according to additional embodiments a fastener  140  is created as a single piece, homogenously formed member. Fastener  140  includes a rounded base  142  having a flat portion  148  and an elongated aperture  150  similar to rounded base  16 , and first and second legs  144 ,  146  extending substantially transverse to flat portion  148 . A first flexible arm  152  homogenously connected to first leg  144  is created and oriented similar to first flexible arm  22 , first flexible arm  152  having a first flexible arm convex portion  156  and a first flexible arm concave portion  158 . Similarly, a second flexible arm  154  homogenously connected to second leg  146  is created and oriented similar to second flexible arm  24 , second flexible arm  154  having a second flexible arm convex portion  160  and a second flexible arm concave portion  162 . First and second elastically displaceable engagement members  164 ,  166  are substantially identical in design and function to first and second engagement members  46 ,  48 , except first and second engagement members  164 ,  166  are homogenously connected to first and second legs  144 ,  146  and are not displaceable with respect to rounded base  142 . 
     Fastener  140  has a fastener height “W”, a base width “Z”, a base height “AA”, and a base length “DD”. According to several embodiments, fastener height “W”, base width “Z”, base height “AA”, and base length “DD” are substantially equal to first member height “A”, first member base width “B”, first member base height “C”, and first member length “F” respectively, of fastener assembly  10 , so that fastener  140  can engage dog-house  98  and provides a similar space envelope for engagement with vehicle body panel  126 . Fastener  140  further includes a flexible arm non-deflected spacing dimension “BB”, and an engagement arm spacing dimension “CC”, which are similar to comparable dimensions of fastener assembly  10 . 
     Referring to  FIG. 22  and again to  FIGS. 15-18 , fastener  140  is engaged within cavity  112  of dog-house  98  in the same manner as fastener assembly  10 . An edge face (not shown) of elongated aperture  150  contacts engagement tooth  114  when rounded base  142  is slidably inserted into cavity  112  in a first direction facing away from the viewer as shown in  FIG. 22 . Similar to fastener assembly  10 , fastener  140  is loaded by pulling or forcing displacement of member  99  in a second direction by a force “Y” (downward as viewed in  FIG. 22 ) which is substantially transverse to the first direction for installation of fastener  140  in dog-house  98  described above. First and second flexible arms  152 ,  154  releasably engage the walls of aperture  124  of vehicle panel  126  in a first engaged position  168  similar to fastener assembly  10 . First and second elastically displaceable engagement members  164 ,  166  contact vehicle body panel  126  in a second engagement position  170  similar to the intermediate engagement position shown in reference to  FIG. 17 . 
     Fastener  140  does not provide the telescoping function of fastener assembly  10 , therefore a clearance dimension “EE” between first and second engaged positions  168 ,  170  of vehicle body panel  126  is less than clearance dimension “V” provided by fastener assembly  10 . Fastener  140  is also used in applications which can include displacement of vehicle member  99  due to expansion or activation of air bag  130 . Similar to fastener assembly  10 , a load or force of approximately 50 pounds is also required to displace dog-house  98  from the first engaged position  168  for fastener  140 , and a load or force of approximately 200 pounds can be withstood by first and second elastically displaceable engagement members  164 ,  166  prior to yielding of the material of the engagement members  164 ,  166 . 
     According to several embodiments, member  99  can support or enclose an air bag assembly (not shown) for an automobile vehicle (not shown). During deployment of the air bag, the fully installed position of fastener assembly  10  in body panel  126  as shown in reference to  FIG. 16  will change to the fully extended position shown in reference to  FIG. 18  having clearance dimension “V”. A high retention capability of fastener assembly  10  is provided as a pull force defined as approximately 200 pounds or greater is required to yield the material of first and second engagement members  46 ,  48  or the first and second tabs  34 ,  34 ′,  36 ,  36 ′. Therefore, deployment of the air bag will not cause displacement in displacement direction “U” of sub-assembly  123  in excess of clearance dimension “V”, thus retaining member  99  in connection with body panel  126 . 
     Referring again to  FIGS. 4 ,  13 ,  17 ,  20 , and  22 , a width “FF” of the slot  106  created in dog-house  98  is adapted to substantially equal or be slightly greater than a spacing between the flexible arm concave portions  74 ,  78 ,  158 ,  162  of fastener assembly  10  and fastener  140 , but width “FF” is less than member base width “B” and base width “Z” of fastener assembly  10  and fastener  140 . The legs ( 18 ,  20 ) of first member  12 , and the second member  14  of fastener assembly  10 , and the legs  144 ,  146  of fastener  140  can therefore extend outward of dog-house  98  through slot  106  of dog-house  98 . Width “FF”, however, prevents rounded base  16  of fastener assembly  10  or rounded base  142  of fastener  140  from being pulled out of cavity  112  when load “Y” is longitudinally or coaxially applied to the fastener ( 10 ,  140 ) which acts to move the rounded base ( 16 ,  142 ) and the dog-house  98  in displacement direction “U”. 
     Fastener assemblies  10  of the present disclosure offer several advantages. A two-stage telescoping design of fastener assembly  10  provides a normally installed position having fastener assembly  10  fully inserted within a body panel of an automobile vehicle. In a first stage or position, the fastener assembly and dog-house are engaged with a body panel of a vehicle. By pulling with or exerting a force greater than approximately 50 pounds on member  99  tending to pull member  99  away from the body panel  126  of the vehicle, a telescoping or sliding motion of the first and second members  12 ,  14  of fastener assembly  10  occurs. A frictional sliding displacement is restrained at a second stage or position by contact between first and second tabs  34 ,  34 ′,  36 ,  36 ′ of second member  14  contacting end walls of tab receiving slots created in first member  12 . The second, displaced position of fastener assembly  10  allows for manual removal of fastener assembly  10  in addition to providing a clearance space between the member  99  and the body panel  126 . Dimples created through the first and second body portions  26 ,  28  of second member  14  which are positioned within the elongated tab receiving slots of first member  12  provide for fastener assembly alignment and prevent rotation of second member  14  with respect to the first member  12 . 
     By frictionally engaging a rounded base of fastener assembly  10  within the dog-house, fastener assembly  10  can be slidably fit into the dog-house in a first or horizontal direction. This engagement position prevents withdrawal of the fastener assembly in a second or longitudinal direction of the fastener assembly which is the direction of load application upon release of an air bag assembly. This connection of the rounded base into or within a cavity of the dog-house improves on fastener designs having bight members within the fastener which externally engage a spade or blade member extending away from a trim member body, but which can release upon application of an air bag deployment load. In the present disclosure, the rounded base can be manually removed from the dog-house by sliding in an opposite direction from the installation direction, but the second direction is still transverse to the load direction applied during air bag deployment. The fastener assembly  10  can also be releasably removed from its second stage engagement with the dog-house by inserting a tool such as a screwdriver into the dog-house and prying the rounded base away from its engagement with the engagement tooth of the dog-house. This provides for complete replacement of fastener assembly  10  and/or complete replacement of member  99 .
A fastener system for use with an air bag includes a fastener having a rounded base having a flat portion, and first and second arms oriented transverse to the flat portion. A first set of engagement devices is connected proximate the rounded base. A second set of engagement devices is connected spatially separated from both the first set and the rounded base. A vehicle component has a dog-house. The rounded base is received and engaged in a dog-house cavity connecting the fastener and vehicle component. The vehicle component displaces upon air bag deployment from a first engagement position having the first engagement device set engaged with a vehicle body panel, to a second engagement position having the second engagement device set engaged with the vehicle body panel. A second fastener sliding part allows telescopic extension of the vehicle component.