Abstract:
Reliable and durable tether clips that continue to tether two panels together while allowing for a controlled displacement between the two panels in response to a predetermined force are disclosed. The tether clips according to the present invention include a first retaining means near a first end that is adapted to be securable to a first panel, a second retaining means that is engageable with the second panel and limits the relative separation between the panels, and a releasable fastener means intermediate the first and second retaining means that normally maintains the two panels in a closed configuration relative to one another but that releases at least one of the panels relative to the other panel in response to a predetermined force tending to separate the panels.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application is a continuation-in-part of U.S. patent application Ser. No. 10/243,803, filed on Sep. 13, 2002, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     This invention relates generally to a panel fastener or clip that normally fastens two panels together but allows for a predetermined displacement between the panels in response to a predetermined force applied to the panels. 
     2. Brief Description of the Related Art 
     In many applications the need arises to fasten one panel to another. For example, in the automotive industry the interior door panels of the vehicle must be securely fastened to the sheet metal forming part of the vehicle door. Many fasteners for this purpose have been proposed in the art. Examples of such panel fasteners can be seen in U.S. Pat. Nos. 5,758,987 and 6,042,296. However, there remains a need in the art for panel fasteners that, while securing two panels together under normal circumstances, will also allow for a controlled displacement between the two panels in response to the application of a predetermined force. An example, of an application requiring this type of fastener is in cars having side airbags that are concealed by the interior door panels. In such cars, when the side airbag inflates in an accident, the panels must be allowed to be displaced relative to one another to allow the airbag to be deployed properly, however, the panels should not be allowed to become completely disconnected. If an interior panel is allowed to separate completely upon deployment of the airbag, then the loose panel could act as a projectile that can cause injury to a vehicle&#39;s occupants. Furthermore, by limiting the displacement between the panels, reinstallation of the panel subsequent to the deployment of the airbag becomes much easier. The need persists in the art for a reliable and durable panel fastener or clip that will continue to tether two panels together while allowing for a controlled displacement between the two panels in response to a predetermined force. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to reliable and durable panel fasteners or tether clips that continue to tether two panels together while allowing for a controlled displacement between the two panels in response to a predetermined force. The panel fasteners or tether clips according to the present invention include a first retaining means near a first end that is adapted to be securable to a first panel, a second retaining means that is engageable with the second panel and limits the relative separation between the panels, and a releasable fastener means intermediate the first and second retaining means that normally maintains the two panels in a closed configuration relative to one another but that releases at least one of the panels relative to the other panel in response to a predetermined force tending to separate the panels. The type of panel fasteners that, while securing two panels together under normal circumstances, will also allow for a controlled displacement between the two panels in response to the application of a predetermined force, are referred to herein as tether clips. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1–3  are views of a first embodiment of a tether clip system according to the present invention. 
         FIGS. 4–8  are views of a second embodiment of a tether clip system according to the present invention. 
         FIGS. 9–13  are views of a third embodiment of a tether clip system according to the present invention. 
         FIGS. 14–27  are views of a fourth embodiment of a tether clip system according to the present invention. 
         FIG. 28  shows a tether clip integrally made with a panel. 
         FIG. 29  is a view of a fifth embodiment of a tether clip system according to the present invention. 
     
    
    
     Like reference numerals indicate like elements throughout the several views. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1–3 , an illustrative example of a tether clip system according to the present invention can be seen. The tether clip system of  FIGS. 1–3  includes a tether clip  100  for fastening a first panel  102  relative to a second panel  104 . The tether clip  100  comprises a first retaining means  106  adapted to be securable to the first panel  102 ; a second retaining means  108  that is engageable with the second panel  104  and limits the relative separation between the first and second panels; and a releasable fastener means  110  intermediate the first and second retaining means  106  and  108 . The releasable fastener means  110  is adapted to be releasably engageable with the second panel  104 . The releasable fastener means  110  is adapted to normally maintain the first and second panels in a closed configuration relative to one another as shown in  FIG. 2 . The releasable fastener means  110  is designed to release the second panel  104  in response to a force tending to separate the first and second panels that is greater than a first predetermined value, thus allowing the panel  104  to move to the position shown in  FIG. 3 . 
     The first panel  102  has a first opening  112  and the second panel  104  has a second opening  114 . The first retaining means  106  comprises a shoulder  116 ; a first body portion  118  projecting from a first side of the shoulder  116  and having an end distal from the shoulder  116 . The first body portion  118  has a first longitudinal axis that is coincident with the longitudinal axis of the tether clip  100 . The first retaining means  106  further includes a first pair of resilient snap legs  120  attached to the first body portion  118  proximate the end of the first body portion distal from the shoulder  116 . 
     Each of the first pair of resilient snap legs  120  has a proximal end and a distal end. Each of the first pair of resilient snap legs  120  is attached to the first body portion  118  proximate the proximal end of each of the first pair of resilient snap legs. Each of the first pair of resilient snap legs  120  extends from the proximal end thereof generally in a direction toward a plane coincident with the first side  122  of the shoulder  116  and at least in part diverging away from the longitudinal axis of the tether clip  100 . 
     Each of the first pair of resilient snap legs  120  has at least one notch  124  provided proximate the distal end of each of the first pair of resilient snap legs  120 . When the first retaining means  106  is secured to the first panel  102 , at least a portion of the first panel  102  proximate the first opening  112  is captured between at least a portion of the shoulder  116  and the notch  124  in each of the first pair of resilient snap legs  120  to thereby secure the tether clip  100  to the first panel  102 . 
     The releasable fastener means  110  comprises a second body portion  126  projecting from a second side  128  of the shoulder  116  and has an end distal from the shoulder  116 . The second body portion  126  has a second longitudinal axis in line with the first longitudinal axis and thus coincident with the longitudinal axis of the tether clip  100 . The releasable fastener means  110  further comprises a second pair of resilient snap legs  130  attached to the second body portion  126  proximate the end of the second body portion distal from the shoulder  116 . 
     Each of the second pair of resilient snap legs  130  has a proximal end and a distal end. Each of the second pair of resilient snap legs  130  is attached to the second body portion  126  proximate the proximal end of each of the second pair of resilient snap legs  130 , and a portion of each of the second pair of resilient snap legs  130  extends from proximate the proximal end of each of the second pair of resilient snap legs generally in a direction toward a plane coincident with the second side  128  of the shoulder and that diverges away from the longitudinal axis of the tether clip  100 . 
     Each of the second pair of resilient snap legs  130  has a surface portion  132  proximate the distal end thereof that converges toward the longitudinal axis of the tether clip with decreasing distance from the second side  128  of the shoulder  116 . When the releasable fastener means  110  is secured to the second panel  104  (as shown in  FIGS. 2 ,  7 , and  8 ) at least a portion of the second panel  104  proximate the second opening  114  is captured between at least a portion of the shoulder  116  and the surface portion  132  proximate the distal end of each of the second pair of resilient snap legs  130  to thereby secure the second panel  104  to the first panel  102  in the closed configuration of  FIGS. 2 ,  7 , and  8 . The surface portion  132  proximate the distal end of each of the second pair of resilient snap legs  130  cooperates with the portion of the second panel  104  proximate the second opening  114  to bend the second pair of resilient snap legs  130  toward the longitudinal axis of the tether clip to thereby allow the second panel  104  to be released from the releasable fastener means  110  to the positions shown in  FIGS. 3 ,  5  and  6  when the releasable fastener means is initially secured to the second panel  104  and a force is tending to move the first and second panels apart and of a magnitude greater than the first predetermined value is applied. 
     The second retaining means  108  comprises a third body portion  138  attached to the releasable fastener means  110  proximate the proximal end of each of the second pair of resilient snap legs  130 . The third body portion  138  has an end distal from the releasable fastener means  110 . The third body portion  138  has a third longitudinal axis in line with the second longitudinal axis and the longitudinal axis of the tether clip  100 . The third body portion  138  has a third pair of resilient snap legs  136  attached to the third body portion  138  proximate the end of the third body portion distal from the releasable fastener means  110 . 
     Each of the third pair of resilient snap legs  136  has a proximal end and a distal end. Each of the third pair of resilient snap legs  136  is attached to the third body portion  138  proximate the proximal end of each of the third pair of resilient snap legs  136 . Each of the third pair of resilient snap legs  136  extends from the proximal end thereof generally in a direction toward a plane coinciding with the second side  128  of the shoulder  116  and at least in part diverges away from the longitudinal axis of the tether clip. 
     Each of the third pair of resilient snap legs  136  has at least one notch  134  provided proximate the distal end of each of the third pair of resilient snap legs  136 . The notch  134  in each of the third pair of resilient snap legs  136  can engage at least a portion of the second panel  104  proximate the second opening  114  to limit the separation between the first and second panels  102  and  104  when the second panel  104  is released by the releasable fastener means  110  (as shown in  FIGS. 3 ,  5 , and  6 ) after being initially secured to the first panel  102  by the releasable fastener means  110 . The snap legs  136  will maintain the panel  104  in the position shown in  FIGS. 3 ,  5 , and  6  as long as any applied force tending to move the first and second panels  102  and  104  further apart is of a magnitude less than a second predetermined value. 
     In the tether clip  100 , wherein a medial plane passing through both the second pair of resilient snap legs  130  is substantially at a right angle measured about the longitudinal axis of the tether clip  100  relative to a medial plane passing through both the third pair of resilient snap legs  136 . 
     The tether clip system of  FIGS. 1–3  also includes up turned portions  140 . The first pair of regions  140  of the portion of the second panel  104  adjacent the second opening  144  are located on opposite sides of the second opening  114  along a first axis. Each of the first pair of regions  140  at least in part project outward from a first side of the second panel  104  facing the first panel  102  to form a pair of ramped surfaces inclined relative to a medial plane of the portion of the second panel  104  having the second opening  114  therein. The regions  140  present a smooth surface for engagement with the snap legs  130  when the second pair of resilient snap legs  130  engage with the portions of the second panel  104  proximate the second opening  114  to bend the second pair of resilient snap legs  130  toward the longitudinal axis of the tether clip to thereby allow the second panel  104  to be released from the releasable fastener means  110 . This feature provides better control of the force required to release the panel  104  from the releasable fastener means  110  and helps prevent snags. 
     The tether clip system of  FIGS. 4–8  is identical to that of  FIGS. 1–3  except for the differences noted below. The tether clip system of  FIGS. 4–8  has a means  142  for increasing retention strength between the second retaining means  108  and the second panel  104  when the second panel has been released from the releasable fastener means  110 . 
     In the tether clip system of  FIGS. 4–8 , the means  142  for increasing retention strength comprises a portion of the second panel  104  having a second opening  114   a  therein. The portion of the second panel  104  surrounding the second opening  114   a  has a first pair of regions  146  that are located on opposite sides of the second opening  114   a  along a first axis. Each of the first pair of regions  146  at least in part project outward from a first side of the second panel  104  facing the first panel  102  to form a pair of ramped surfaces inclined relative to a medial plane of the portion of the second panel  104  having the second opening  114   a  therein. A second pair of regions  144  of the portion of the second panel  104  adjacent the second opening  114   a  are also located on opposite sides of the second opening  114   a , but along a second axis that is perpendicular to the first axis between the regions  146  in plan view. Each of the second pair of regions  144  at least in part project outward from a second side of the second panel opposite the first side of the second panel  104  and provide a catch that more positively engages the snap legs  136  as shown in  FIGS. 5 and 6 . The means  142  for increasing retention strength comprises the regions  144 . 
     As an example of the use of the tether clip  100 , Panel  102  may be the interior panel of the door of a motor vehicle and the panel  104  may be the sheet metal of the door. The retaining means  106  is attached to the panel  102  by pressing in the portion  118  into the hole  112 . The sides of the hole  112  deform the snap legs  120 . Once the notches  124  clear the panel  102 , the snap legs  120  snap open behind the panel  102  to secure the tether clip  100  to the panel  102 . Once the airbag is in place the second retaining means  108  is pushed through the hole  114  or  114   a . As with snap legs  120 , snap legs  136  deform by the action of the sides of the hole  114  or  114   a  to allow the snap legs  136  to pass through the hole  114  or  114   a  and open up behind the panel  104  to prevent the tether clip  100  from being pulled completely out of the hole  114  or  114   a  unless a force exceeding the second predetermined force is applied to the panels. The panel  104  can now move freely between the retaining means  108  and the releasable fastener means  110 . To secure the panel  102  in its normal position, the releasable fastener means  110  is snapped into the hole  114  or  114   a . The snap legs  130  deform by the action of the sides of the hole  114  or  114   a  to allow the snap legs  130  to pass through the hole  114  or  114   a  and open up behind the panel  104  to secure the panel  102  in the normal position of  FIGS. 2 ,  7 , and  8 . 
     When the airbag inflates, a force in excess of the first predetermined value and tending to pull the panels apart is created. The ramped surfaces  132  catch the edges of the hole  114  or  114   a  in a cam action that bends the snap legs  130  toward the longitudinal axis of the tether clip  100 . This allows the insertion process of the releasable fastener means  110  to be reversed and for the releasable fastener means  110  to release the panel  104 . As the airbag inflates further, the snap legs  136  catch the panel  104  and prevent the panel  102  from being pulled completely free from the vehicle door panel  104 . Thus, an opening between panels  102  and  104  can be provided for the proper inflation of the airbag without allowing the panel  102  to become a projectile. The snap legs  136  are designed such that they fail at forces greater than a second predetermined value that is higher than the forces encountered during airbag deployment. The second predetermined value is usually greater that the first predetermined value. The first predetermined value can range from 10 to 50 lbs., and preferably from about 20 to about 30 lbs., and even more preferably from 20 to 30 lbs. The second predetermined value can be in the range of 75 lbs. and greater, and preferably is in the range of about 150 lbs. and greater, and even more preferably about 150 lbs. The travel between the panels  102  and  104  during airbag deployment is about 25 mm. 
     Referring to  FIGS. 9–13 , a third illustrative embodiment of a tether clip system according to the present invention can be seen. The tether clip system of  FIGS. 9–13  includes a tether clip  200 , for fastening a first panel  202  relative to a second panel  204 , and a receptacle  250 . The tether clip  200  comprises a first retaining means  206  adapted to be securable to the first panel  202 ; a second retaining means  208  that is engageable with the second panel  204  and limits the relative separation between the first and second panels; and a releasable fastener means  210  intermediate the first and second retaining means  206  and  208 . The releasable fastener means  210  is adapted to be releasably engageable with the second panel  204 . The releasable fastener means  210  is adapted to normally maintain the first and second panels in a closed configuration relative to one another as shown in  FIGS. 10 and 11 . The releasable fastener means  210  is designed to release the second panel  204  in response to a force tending to separate the first and second panels that is greater than a first predetermined value, thus allowing the panel  204  to move to the position shown in  FIGS. 12 and 13 . 
     The first panel  202  has a first opening  212  and the second panel  204  has a second opening  214 . The opening  214  is adapted to receive the receptacle  250 . The receptacle  250  has a portion  252  defining a receptacle opening  254  that is aligned with the second opening  214  when the receptacle  250  is mounted to the second panel  204 . The receptacle  250  further comprises at least one flange-like portion  256  adapted to engage a first side of the second panel  204  facing the first panel  202  when the receptacle  250  is mounted to the second panel  204 . The receptacle  250  further comprises a U-shaped leaf spring member  258  having a first terminus  260  and a second terminus  262 . The U-shaped leaf spring member  258  is made of a resilient material. The U-shaped leaf spring member  258  has a first arm portion  264  adjacent the first terminus  260  and a second arm portion  266  adjacent the second terminus  262 . 
     The U-shaped leaf spring member  258  is attached proximate the first terminus  260  to the portion  252  defining the receptacle opening  254 . The U-shaped leaf spring member  258  has a projection  268  on the second arm member  266 . The projection  268  has an inclined ramp surface on one side and a catch surface on the other side. The catch surface of the projection  268  is engageable to a second side of the second panel  204  opposite the first side of the second panel, when the receptacle is mounted to the second panel  204 , to thereby secure the receptacle  250  to the second panel  204 . The second side of the panel  204  is the side that faces away from the panel  202  when the two panels are fastened together by the tether clip  200 . 
     The opening  214  in panel  204  is in the form of a circular opening portion  270  that has a first slot  272  extending from one side and a second, shorter slot  274  extending from the other side. The slot  274  may optionally have a guide notch  276 . The slot  274  is provides clearance for the attachment portion of the tab  278  that is attached to the receptacle portion  252 . The tab  278  has a catch surface  280  that contacts the second side of the panel  204  to more strongly retain the receptacle  250  on the panel  204 . The receptacle  250  has an optional guide fin  282  that fits into the guide notch  276 . The guide notch  276  and guide fin  282  cooperatively help to align the U-shaped leaf spring member  258  with the slot  272 . 
     To install the receptacle  250  to the panel  204 , the receptacle  250  is canted and the tab  278  is positioned in the slot  274  such that the catch surface  280  is positioned under the second side of the panel  204  with the guide fin  282  positioned in the guide notch  276 . In this position, the U-shaped leaf spring member  258  is aligned with and positioned at least in part in the slot  272 . The side of the receptacle portion  252  to which the U-shaped leaf spring member  258  is attached is then pushed in toward the panel  204 . As the inclined ramp surface of the projection  268  comes into contact with the squared-off end of the slot  272 , the arms  264  and  266  of the U-shaped leaf spring member  258  are brought together such that the projection  268  clears the squared-off end of the slot  272 . The side of the receptacle portion  252  to which the U-shaped leaf spring member  258  is attached is then pushed in further until the underside of the flange portions  256  contact the first surface of the panel  204 . The arm portion  266  of the U-shaped leaf spring member  258  then snaps back toward its original position relative to the arm portion  264  of the U-shaped leaf spring member  258  such that the catch surface of the projection  268  snaps under the second side of the second panel  204  to thereby secure the receptacle  250  to the second panel  204 . When the receptacle  250  is secured to the panel  204 , portions of the panel  204  around the opening  214  are captured between flange-like portions  256  on one side and the catch surface of the projection  268  and the catch surface  280  of the tab  278  on the other side to secure the receptacle  250  to the panel  204 . 
     An annular shoulder is provided in the bore of the opening  254 . In the example of  FIGS. 9–13 , this annular shoulder is provided by an annular, internal flange  284  provided in the bore of the opening  254 . The function of the shoulder in the bore of the opening  254  is explained below. 
     The first retaining means  206  comprises a shoulder  216 ; a first body portion  218  projecting from a first side of the shoulder  216  and having an end distal from the shoulder  216 . The first body portion  218  has a first longitudinal axis that is coincident with the longitudinal axis of the tether clip  200 . The first retaining means  206  further includes a first pair of resilient snap legs  220  attached to the first body portion  218  proximate the end of the first body portion distal from the shoulder  216 . 
     Each of the first pair of resilient snap legs  220  has a proximal end and a distal end. Each of the first pair of resilient snap legs  220  is attached to the first body portion  218  proximate the proximal end of each of the first pair of resilient snap legs. Each of the first pair of resilient snap legs  220  extends from the proximal end thereof generally in a direction toward a plane coincident with the first side  222  of the shoulder  216  and at least in part diverging away from the longitudinal axis of the tether clip  200 . 
     Each of the first pair of resilient snap legs  220  has at least one notch  224  provided proximate the distal end of each of the first pair of resilient snap legs  220 . When the first retaining means  206  is secured to the first panel  202 , at least a portion of the first panel  202  proximate the first opening  212  is captured between at least a portion of the shoulder  216  and the notch  224  in each of the first pair of resilient snap legs  220  to thereby secure the tether clip  200  to the first panel  202 . 
     The releasable fastener means  210  comprises a second body portion  226  projecting from a second side  228  of the shoulder  216  and has an end distal from the shoulder  216 . The second body portion  226  has a second longitudinal axis in line with the first longitudinal axis and thus coincident with the longitudinal axis of the tether clip  200 . The releasable fastener means  210  further comprises a second pair of resilient snap legs  230  attached to the second body portion  226  proximate the end of the second body portion distal from the shoulder  216 . 
     Each of the second pair of resilient snap legs  230  has a proximal end and a distal end. Each of the second pair of resilient snap legs  230  is attached to the second body portion  226  proximate the proximal end of each of the second pair of resilient snap legs  230 , and a portion of each of the second pair of resilient snap legs  230  extends from proximate the proximal end of each of the second pair of resilient snap legs generally in a direction toward a plane coincident with the second side  228  of the shoulder and that diverges away from the longitudinal axis of the tether clip  200 . 
     Each of the second pair of resilient snap legs  230  has a surface portion  232  proximate the distal end thereof that converges toward the longitudinal axis of the tether clip with decreasing distance from the second side  228  of the shoulder  216 . When the releasable fastener means  210  is secured to the second panel  204  via the receptacle  250  (as shown in  FIGS. 10 and 11 ) at least a portion of the receptacle  250  proximate the receptacle opening  254  is captured between at least a portion of the shoulder  216  and the surface portion  232  proximate the distal end of each of the second pair of resilient snap legs  230  to thereby secure the second panel  204  to the first panel  202  in the closed configuration of  FIGS. 10 and 11 . The surface portion  232  proximate the distal end of each of the second pair of resilient snap legs  230  cooperates with the portion of the receptacle  250  proximate the receptacle opening  254  to bend the second pair of resilient snap legs  230  toward the longitudinal axis of the tether clip to thereby allow the second panel  204  to be released from the releasable fastener means  210  to the positions shown in  FIGS. 12 and 13  when the releasable fastener means is initially secured to the receptacle  250  installed in the second panel  204  and a force is applied that tends to move the first and second panels apart and that is of a magnitude greater than the first predetermined value. 
     The second retaining means  208  comprises a third body portion  238  attached to the releasable fastener means  210  proximate the proximal end of each of the second pair of resilient snap legs  230 . The third body portion  238  has an end distal from the releasable fastener means  210 . The third body portion  238  has a third longitudinal axis in line with the second longitudinal axis and the longitudinal axis of the tether clip  200 . The third body portion  238  has a third pair of resilient snap legs  236  attached to the third body portion  238  proximate the end of the third body portion distal from the releasable fastener means  210 . 
     Each of the third pair of resilient snap legs  236  has a proximal end and a distal end. Each of the third pair of resilient snap legs  236  is attached to the third body portion  238  proximate the proximal end of each of the third pair of resilient snap legs  236 . Each of the third pair of resilient snap legs  236  extends from the proximal end thereof generally in a direction toward a plane coinciding with the second side  228  of the shoulder  216  and at least in part diverges away from the longitudinal axis of the tether clip. 
     Each of the third pair of resilient snap legs  236  has at least one notch  234  provided proximate the distal end of each of the third pair of resilient snap legs  236 . The notch  234  in each of the third pair of resilient snap legs  236  can engage at least a portion of the shoulder defined by the flange  284  in the bore of the receptacle opening  254  to limit the separation between the first and second panels  202  and  204  when the second panel  204  is released by the releasable fastener means  210  (as shown in FIGS.  12  and  13 ) after being initially secured to the first panel  202  by the releasable fastener means  210 . The snap legs  236  will maintain the panel  204  in the position shown in  FIGS. 12 and 13  as long as any applied force tending to move the first and second panels  202  and  204  further apart is of a magnitude less than a second predetermined value. 
     In the tether clip  200 , a medial plane passing through both the second pair of resilient snap legs  230  is substantially coplanar with a medial plane passing through both the third pair of resilient snap legs  236 . The body portion  238  has a relatively large width at a position along its length corresponding approximately to the distal ends of the resilient snap legs  236 . This relatively large width is slightly smaller than the interior diameter of the annular flange  284  and ensures that the resilient snap legs  236  are properly positioned relative to the receptacle opening  254  just before the distal ends of the resilient snap legs  236  contact the shoulder in the bore of the receptacle opening  254 . The body portion  238  has a narrower width proximate the proximal end of each of the second pair of resilient snap legs  230  as compared to the portion having the relatively large width located at the position along the length of the body portion  238  corresponding approximately to the distal ends of the resilient snap legs  236 . The portion of the body portion  238  extending from proximate the proximal end of each of the second pair of resilient snap legs  230  to the position corresponding approximately to the distal ends of the resilient snap legs  236 , is cored out to save on material costs and weight thus forming the opening  240 . 
     The tether clip  200  may be directly fastened to the second panel  204  in the same manner as the tether clip of  FIGS. 1–3 . However, using the receptacle  250  has several advantages. First, the cost and difficulty of providing the complex geometry of the holes such as those in the panels  104  of  FIGS. 1–8  is avoided. By having better control over the geometry and materials of the structures that come in contact the releasable fastener means and the second retaining means, the required release force specifications can be more accurately met. The material of the receptacle  250  can be selected for better compatibility with the releasable fastener means and the second retaining means to reduce wear and damage to these parts. Particularly if the panels  104  and  204  are of sheet metal, using the receptacle  250  can prevent contact between the tether clip and sharp edges in the sheet metal that could cause the tether clip to fail. 
     As an example of the use of the tether clip  200 , Panel  202  may be the interior panel of the door of a motor vehicle and the panel  204  may be the sheet metal of the door. The retaining means  206  is attached to the panel  202  by pressing in the portion  218  into the hole  212 . The sides of the hole  212  deform the snap legs  220 . Once the notches  224  clear the panel  102 , the snap legs  220  snap open behind the panel  202  to secure the tether clip  200  to the panel  202 . The receptacle  250  is installed in the hole  214  of panel  204  as previously described. Once the airbag is in place the second retaining means  208  is pushed through the hole  254  of the receptacle  250 . As with snap legs  220 , snap legs  236  deform by the action of the sides of the hole  254  to allow the snap legs  236  to pass through the hole  254  and open up behind the shoulder in the bore of the hole  254  to prevent the tether clip  200  from being pulled completely out of the receptacle  250  unless a force exceeding the second predetermined force is applied to the panels. The panel  204  can now move freely between the retaining means  208  and the releasable fastener means  210 . To secure the panel  202  in its normal position, the releasable fastener means  210  is snapped into the hole  254 . The snap legs  230  deform by the action of the sides of the hole  254  to allow the snap legs  230  to pass through the hole  254  and open up behind the opening  254  to secure the panel  202  in the normal position of  FIGS. 10 and 11 . 
     When the airbag inflates, a force in excess of the first predetermined value and tending to pull the panels apart is created. The ramped surfaces  232  catch the edges of the hole  254  in a cam action that bends the snap legs  230  toward the longitudinal axis of the tether clip  200 . This allows the insertion process of the releasable fastener means  210  to be reversed and for the releasable fastener means  210  to release the panel  204 . As the airbag inflates further, the snap legs  236  catch the receptacle  250  and consequently the panel  204  and prevent the panel  202  from being pulled completely free from the vehicle door panel  204 . Thus, an opening between panels  202  and  204  can be provided for the proper inflation of the airbag without allowing the panel  202  to become a projectile. The snap legs  236  are designed such that they fail at forces greater than a second predetermined value that is higher than the forces encountered during airbag deployment. The second predetermined value is usually greater that the first predetermined value. The first predetermined value can range from 10 to 50 lbs., and preferably from about 20 to about 30 lbs., and even more preferably from 20 to 30 lbs. The second predetermined value can be in the range of 75 lbs. and greater, and preferably is in the range of about 150 lbs. and greater, and even more preferably is about 150 lbs. The travel between the panels  202  and  204  during airbag deployment is about 25 mm. 
     Referring to  FIGS. 14–27 , a fourth illustrative embodiment of a tether clip system according to the present invention can be seen. The tether clip system of  FIGS. 14–27  is used for fastening a first panel  302  having a first opening  312  in a closed configuration relative to a second panel  304  having a second opening  314 . The tether clip system of  FIGS. 14–27  includes a tether clip  300  and a receptacle  350 . The receptacle  350  is adapted for mounting to the second opening  314  in the second panel  304 . 
     The tether clip  300  includes first retaining means  306  adapted to be securable to the first panel  302  and second retaining means  308 . The second retaining means  308  engages with the receptacle  350  in order to limit the relative separation between the first and second panels  302  and  304 , when the receptacle  350  is mounted to the second panel  404 , the tether clip  300  is mounted to the first panel  302 , and the first and second panels  302  and  304  are in an open configuration relative to one another (see  FIGS. 17 and 18 ). 
     The tether clip system of  FIGS. 14–27 , also includes releasable fastener means adapted to releasably engage the tether clip  300  to the receptacle  350  when the receptacle is mounted to the second panel  304 , the tether clip  300  is mounted to the first panel  302 , and the first and second panels  302  and  304  are in a closed configuration relative to one another (see  FIGS. 15 and 16 ). The releasable fastener means is adapted to normally maintain the first and second panels  302 ,  304  in a closed configuration relative to one another as shown in  FIGS. 15 and 16 . The receptacle  350  is also in a closed position relative to the tether clip  300  when the first and second panels  302 ,  304  are in a closed configuration relative to one another. The releasable fastener means allows the receptacle  350  to be released from its closed position relative to the tether clip  300  in response to a force tending to separate the first and second panels  302 ,  304  that is greater than a first predetermined value. The releasable fastener means is formed in part by portions of the receptacle  350  and in part by portions of the tether clip  300 . 
     The tether clip  300  is formed by an elongated body having a longitudinal axis, a first end  315 , a second end  317 , and a shoulder  316  located intermediate the first end and the second end. The tether clip  300  has a portion  310  having a first maximum width and located intermediate the shoulder  316  and the second end  317 . The tether clip  300  has a portion  326  having a second maximum width greater than the first maximum width and located intermediate the portion  310  having the first maximum width and the second end  317 . The tether clip  300  has a portion  338  having a third maximum width less than the second maximum width and located intermediate the portion  326  having the second maximum width and the second end  317 . The tether clip  300  has a catch surface  334  that is spaced apart from the portion  326  having the second maximum width. The portion  338  having the third maximum width is located intermediate the portion  326  having the second maximum width and the catch surface  334 . 
     The tether clip  300  also has a pair of resilient snap legs  320  attached to the elongated body at a location along a portion  318  of the elongated body forming the tether clip  300 . The portion  318  of the elongated body extends from the shoulder  316  to the first end  315  of the elongated body and includes the first end  315  of the elongated body. 
     Each of the pair of resilient snap legs  320  has a proximal end and a distal end. Each of the pair of resilient snap legs  320  is attached to the elongated body proximate the proximal end of each of the pair of resilient snap legs  320 . Each of the pair of resilient snap legs  320  extends from the proximal end thereof generally in a direction toward a plane coincident with the shoulder  316  and at least in part diverging away from the longitudinal axis of the elongated body forming the tether clip  300 . 
     Each of the pair of resilient snap legs  320  has at least one notch  324  provided proximate the distal end of each of the pair of resilient snap legs  320 . The first retaining means  306  includes the pair of resilient snap legs  320 . When the first retaining means  306  is secured to the first panel  302 , at least a portion of the first panel  302  proximate the first opening  312  is captured between at least a portion of the shoulder  316  and the notch  324  in each of the pair of resilient snap legs  320  to thereby secure the tether clip  300  to the first panel  302 . 
     The receptacle  350  includes two receptacle body portions  352  that are mirror images of one another. The receptacle  350  includes flange-like portions  356  attached to each of the receptacle body portions  352  and adapted to engage a first side of the second panel  304  facing the first panel  302  when the receptacle  350  is mounted to the second panel  304 . 
     The receptacle  350  includes two roughly U-shaped leaf spring members  358 . Each U-shaped leaf spring member  358  has a first terminus  360  and a second terminus  362 . Each U-shaped leaf spring member  358  has a first arm portion  364  adjacent the first terminus  360  and a second arm portion  366  adjacent the second terminus  362 . The first terminus  360  of each U-shaped leaf spring member  358  is attached to a respective one of the receptacle body portions  352  and the second terminus  362  of each U-shaped leaf spring member  358  is attached to the other one of the receptacle body portions  352 . Each the U-shaped leaf spring member  358  has a projection  368  on each arm member  364 ,  366 . Each projection  368  has an inclined ramp surface  367  on one side and a catch surface  369  on the other side. The catch surface  369  engages a second side of the second panel  304  when the receptacle  350  is mounted to the second panel  304  to thereby secure the receptacle  350  to the second panel  304 . The second side of the second panel  304  is opposite the first side of the second panel  304  and in use faces away from the first panel  302 . 
     The receptacle  350  includes at least one resilient finger  354  attached to the receptacle body portion  352 . In the illustrated example there are six resilient fingers  354 . Each resilient finger  354  is engageable with the portion  310  of the elongated body having the first maximum width to thereby releasably retain the receptacle  350 , and consequently the panel  304 , in a closed position relative to the tether clip  300 . 
     The portion  310  of the elongated body having the first maximum width and the portion  326  of the elongated body having the second maximum width cooperatively define a depression in the elongated body forming the tether clip  300  that can be engaged by the resilient fingers  354  to thereby releasably retain the receptacle  350  in a closed position relative to the tether clip  300 . In the embodiment of  FIGS. 14–27 , the releasable fastener means includes the resilient fingers  354  and the depression cooperatively defined by the portion  310  of the elongated body having the first maximum width and the portion  326  of the elongated body having the second maximum width. 
     In the illustrated example, the resilient fingers  354  extend into the opening  314  in plan view when the receptacle  350  is installed in the panel  304 . Also the resilient fingers  354  slope down toward the catch surface  334  when the receptacle  350  is in the closed position relative to tether clip  300 . 
     The opening  314  in panel  304  is in the form of a circular opening portion  370  that has a first slot  372  extending from one side and a second  372  extending from the other side. To install the receptacle  350  to the panel  304 , the receptacle  350  is positioned over the opening  314  such that the U-shaped leaf spring members  358  are aligned with and positioned at least in part in the slots  372 . The receptacle  350  is then pushed in toward the panel  204 . As the inclined ramp surfaces of the projections  368  come into contact with the sides of the slots  372 , the arms  364  and  366  of the U-shaped leaf spring members  358  are brought together such that the projections  368  clear the slots  372 . The receptacle  350  is then pushed in further until the underside of the flange portions  356  contact the first surface of the panel  304 . The arm portions  366  of the U-shaped leaf spring members  358  then snap back toward their original positions relative to the arm portions  364  such that the catch surfaces  369  of the projections  268  snap under the second side of the second panel  304  to thereby secure the receptacle  350  to the second panel  304 . When the receptacle  350  is secured to the panel  304 , portions of the panel  304  around the opening  314  are captured between flange-like portions  356  on one side and the catch surfaces  369  of the projections  368  on the other side to secure the receptacle  350  to the panel  304 . 
     As an example of the use of the tether clip  300 , Panel  302  may be the interior panel of the door of a motor vehicle and the panel  304  may be the sheet metal of the door. The retaining means  306  is attached to the panel  302  by pressing in the portion  318  into the hole  312 . The sides of the hole  312  deform the snap legs  320 . Once the notches  324  clear the panel  302 , the snap legs  320  snap open behind the panel  302  to secure the tether clip  300  to the panel  302 . The receptacle  350  is installed in the hole  314  of panel  304  as previously described. Once the airbag is in place the second retaining means  308  is pushed through the receptacle  350 . The resilient fingers  354  will flex under the pressure of the bulbous portion of the tether clip near the end  317  and the resilient fingers will snap back once the resilient fingers  354  clear the catch surface  334 . Because of the angle of the resilient fingers relative to the catch surface  334 , pulling the tether clip  300  completely out of receptacle  350  is far more difficult than initially pushing the bulbous end of the tether clip  300  through the receptacle  350 . Engagement of the catch surface  334  with the resilient fingers in an attempt to completely pull the tether clip  300  out of the receptacle  350  will actually force the resilient fingers toward the center of the hole  314  and into greater interference with the catch surface  334 . Thus, the tether clip  300  is prevented from being pulled completely out of the receptacle  350  unless a force exceeding the second predetermined force is applied to the panels. The panel  304  can now move freely between the retaining means  308  and the portion  326  of the tether clip  300 . To secure the panel  302  in its normal position, the larger width portion  326  of the tether clip  300  is snapped through or past the resilient fingers  354 . The resilient fingers  354  deform by the action of the gradually widening sides of the portions  338  and  326  of the tether clip to allow the widest part of the portion  326  to pass through the resilient fingers  354 . The resilient fingers  354  then snap into the narrowest part of the portion  310  of the tether clip  300  to secure the panel  302  in the normal position of  FIGS. 15 and 16 . 
     When the airbag inflates, a force in excess of the first predetermined value and tending to pull the panels apart is created. The ramped surfaces between the narrowest and widest parts of the portions  310  and  326  of the tether clip  300 , respectively, spread the resilient fingers  354  apart allowing the receptacle  350  to be released from its closed position relative to the tether clip  300 . Thus, the panel  302  is released from the closed position relative to the panel  304 . As the airbag inflates further, the catch surface  334  catches the receptacle  350  and consequently the panel  304  and prevents the panel  302  from being pulled completely free from the vehicle door panel  304 . Thus, an opening between panels  302  and  304  can be provided for the proper inflation of the airbag without allowing the panel  302  to become a projectile. The resilient fingers  354  are designed such that they fail at forces greater than a second predetermined value that is higher than the forces encountered during airbag deployment. The second predetermined value is usually greater that the first predetermined value. The first predetermined value can range from 10 to 50 lbs., and preferably from about 20 to about 30 lbs., and even more preferably from 20 to 30 lbs. The second predetermined value can be in the range of 75 lbs. and greater, and preferably is in the range of about 150 lbs. and greater, and even more preferably is about 150 lbs. The travel between the panels  302  and  304  during airbag deployment is about 25 mm. 
     In certain applications it may be possible to make the tether clip  300  integral with the panel  302  such that the panel  302  and the portion of the tether clip  300  extending between the shoulder  316  and the second end  317  are one piece. An example of such an application is seen in  FIG. 28 . 
     Referring to  FIG. 29 , a fifth illustrative embodiment of a tether clip system according to the present invention can be seen. The tether clip system of  FIG. 29  includes a tether clip  400  and a receptacle  450 . The receptacle  450  has a central passage  454  and projections  468 . The projections  468  snap into a panel such as  304 . The receptacle  450  has a peripheral groove  452  in a large diameter portion  456  thereof. The tether clip  400  has a quarter-turn fastener  406  at one end and a somewhat pointed bulbous end  408  at the other end. The quarter-turn fastener fits into a slot in a panel such as panel  302  and is turned a quarter of a turn to fasten the tether clip  400  to the panel. The bulbous end  408  can be inserted completely through the passage  454 , but can only be pulled out with the greatest difficulty by using a pulling force exceeding the second predetermined value mentioned previously. Projections  436  resiliently, laterally supported by members  410  snap into grooves  452  to releasably maintain two panels in a closed position relative to one another. If the panels are subjected to a force greater than the first predetermined value previously mentioned, the projections  436  snap out of the groove  452 , thus releasing the panels relative to one another. The opening between the panels is limited by the bulbous end  408  that is supported at a predetermined distance from the members  410  by the shaft  438 . The members  410  may be part of a cylindrical cap that has the shaft  438  attached to its center. 
     It is to be understood that the present invention is not limited to the embodiments described above, but includes any and all embodiments within the scope of the appended claims. Furthermore, it is to be understood that the embodiments of the present invention disclosed above are susceptible to various modifications, changes and adaptations by those skilled in the art, without departing from the spirit and scope of the invention.