Abstract:
A bracket for a vehicle is provided including a four-way fastener locator portion and a slip plane portion. The fastener locator portion includes a cross-member configured to allow passage therethrough of a portion of a fastener received in the fastener-receiving portion on application of a force meeting or exceeding a predetermined impact load. Assemblies including the provided bracket are described.

Description:
TECHNICAL FIELD 
       [0001]    This disclosure relates generally to brackets for motor vehicle components, and more particularly to bracket exhibiting improved impact loading performance. 
       BACKGROUND 
       [0002]    Safety regulations dictate, in the event of an impact such as a motor vehicle collision, that the amount of force/energy transmitted to the vehicle occupant&#39;s body cannot exceed a predetermined level in order to minimize the risk and/or severity of injury to the occupant. One way this is accomplished is to provide specific crumple zones in vehicle modules/panels, which absorb a portion of the energy of impact. Another way is to provide specific impact loading specifications, i.e., areas and structural features of the motor vehicle which are designed to fail at a predetermined impact load in order to mitigate and reduce the level of impact force transmitted to the occupant. In particular, it is known to provide brackets designed to fail at a predetermined impact load to accomplish this goal. 
         [0003]    However, motor vehicle brackets and fasteners must meet certain durability/assembly requirements. For example, brackets and fasteners must be designed not to fail below preset limits, and also are often required to include design features which assist in alignment of the particular vehicle components which they secure. As an example, with reference to  FIGS. 1A and 1B , conventional molded or cast bracket structures  10  for securing vehicle components (generically depicted as C, C′) one to another typically include a fastener locator portion  12  designed to auto-locate a fastener F such as a bolt or screw in a desired orientation for securing the bracket to a vehicle component. Conventional brackets  10  also typically include a solid body  14  which may optionally include one or more strengthening rib structures  16  to provide further stability and strength to the bracket. As depicted, bracket  10  is integral to the structure of vehicle component C, but the skilled artisan will readily appreciate that the bracket  10  may equally be a separately cast or molded piece. Because the bracket  10  presents a unitary body aligning the fastener locator portion  12  with a cooperating aperture  18  in a cooperating bracket structure  19  on an adjoining component C′, vehicle components C, C′ are rigidly secured to one another and there is no mitigation of impact force unless the bracket  10  completely fails and/or one or both of components C, C′ crumple or crush in the event of a collision. 
         [0004]    With reference to  FIG. 1C , another prior art bracket  10 ′ is shown which is designed to provide some impact force mitigation. The bracket  10 ′ includes a fastener F locator portion  12 ′ and a slip plane portion  18 . In the depicted bracket, a two-way fastener locator portion  15  is provided by an arcuate top bracket edge. Arms  16 ′,  16 ′ depend from the top edge. The space  19  between the top edge and component C is substantially open. As will be appreciated, in the event of a direct or indirectly transmitted impact to component C, an impact load will be transmitted in the direction of fastener F (see arrow). As will be appreciated, this causes bracket  10 ′ and fastener F to function as a slip joint providing a certain degree of slippage on impact. The impact load at which the attachment between fastener F and the top edge will slip through space  19  is determined by fastener F clamping force. It is therefore very difficult to provide a precisely controlled slip plane which will slip only at a desired impact load. Moreover, over time and with the vibration encountered during vehicle use, fastener F may loosen resulting in noise, component vibration, etc. 
         [0005]    Other bracket design options which are designed to reduce the impact forces transmitted by vehicle components/modules to lessen/mitigate risk and/or severity of injury can result in poorly secured or misaligned vehicle components, poor tactile “feel” of the vehicle to the vehicle user, noise issues such as squeaking/rattling, excessive vibration, etc. This can create customer dissatisfaction with vehicle quality, fit, and finish. On the other hand, brackets/fasteners which strengthen such areas may cause impact forces to a vehicle occupant to exceed desired levels. Thus, designing brackets and other attachments which are sufficiently durable, which provide other desirable features such as fastener location, but which are also designed to fail at a predetermined impact load presents a significant engineering challenge. 
         [0006]    To satisfy this identified need in the art, the present disclosure describes a bracket for securing vehicle components/modules one to another. The described bracket includes suitable fastener locator structures, provides a durable structure providing a secure attachment of components during ordinary use, but is also designed to slip at a predetermined impact load in order to reduce the impact forces transmitted in the event of a collision. Advantageously, the bracket includes a slip plane portion providing a slip joint feature designed to cause joint or connection point slippage at a predetermined impact load. This slip joint feature is advantageous, in that the bracket on receiving a predetermined impact will slip rather than completely failing, providing an impact absorbing function without completely releasing the connection between the components. The described bracket further includes a “tunable” portion which allows the designer to increase or decrease the predetermined impact load which will cause the bracket to slip. 
       SUMMARY 
       [0007]    In accordance with the purposes and benefits described herein, in one aspect a bracket is provided including a body having at least a fastener locator portion and a slip plane portion. The slip plane portion is designed to fail at a predetermined impact load, thus allowing a certain degree of slippage of a connection between vehicle components on impact to absorb a portion of the impact force. 
         [0008]    In embodiments, the slip plane portion is tunable, that is, may be manufactured to fail/rupture at a higher or a lower impact force according to desired or required properties for the bracket such as durability, vibration transmission, and others. In still other embodiments, elements of the slip plane portion may be designed to focus impact load in a desired direction. 
         [0009]    In the following description, there are shown and described embodiments of the disclosed bracket. As it should be realized, the bracket is capable of other, different embodiments and its several details are capable of modification in various, obvious aspects all without departing from the devices and methods as set forth and described in the following claims. Accordingly, the drawings and descriptions should be regarded as illustrative in nature and not as restrictive. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The accompanying drawing figures incorporated herein and forming a part of the specification, illustrate several aspects of a fascia attachment system for securing a vehicle fascia and/or components thereof to other vehicle components or to the structural architecture of a vehicle, for example a vehicle bolster, and together with the description serve to explain certain principles thereof. In the drawing: 
           [0011]      FIG. 1A  depicts a prior art bracket system securing vehicle components to one another; 
           [0012]      FIG. 1B  depicts a prior art bracket for use in the system of  FIG. 1A ; 
           [0013]      FIG. 1C  depicts another prior art bracket for use in the system of  FIG. 1A ; 
           [0014]      FIG. 2A  depicts an embodiment of a bracket according to the present disclosure; 
           [0015]      FIG. 2B  depicts an alternative embodiment of the bracket of  FIG. 2A ; 
           [0016]      FIG. 2C  depicts another alternative embodiment of the bracket of  FIG. 2A ; 
           [0017]      FIG. 2D  depicts yet another alternative embodiment of the bracket of  FIG. 2A ; 
           [0018]      FIG. 2E  depicts still another alternative embodiment of the bracket of  FIG. 2A ; and 
           [0019]      FIG. 3  depicts vehicle components attached to one another by a bracket according to the present disclosure. 
           [0020]    Reference will now be made in detail to embodiments of the disclosed bracket, examples of which are illustrated in the accompanying drawing figures. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    To solve the aforementioned and other problems, the present disclosure at a high level relates to a bracket comprising at least a fastener locator portion and a slip plane portion. In the drawings, like features are numbered with like reference numerals but distinguished by reference letters (a,b,c, . . . n, etc.). As is known, a number of suitable materials for manufacturing such brackets are known in the art, including metals, alloys, polymers such as glass-filled polypropylene (30%), plastics, and others. However, any suitable material for fabricating/molding brackets according to the present description is contemplated. Accordingly, any such descriptions should not be taken to be limiting in any way. 
         [0022]    As summarized above in the discussion of  FIG. 1C , use only of a friction/interference fit between a fastener F and a bracket to provide a slip plane is suboptimal, because providing a slip plane that will slip at a precise desired impact load is nearly impossible, since the slip plane relies only on bolt clamping force. Therefore, to solve this problem a bracket  20   a  is provided (see  FIG. 2A ) including a fastener F locator portion  22   a  and a slip plane portion  24   a.  As shown, locator portion  22   a  is defined by a top edge  26   a  and a tunable cross-member  32   a  which cooperate to define a four-way fastener locator portion  22   a.  As will be appreciated, by “tunable” it is meant that a thickness and/or a configuration of cross-member  32   a  may be altered to provide a cross-member that will rupture only on application of a force equaling or exceeding a predetermined impact load to allow slippage of a fastener F along arms  28   a,    28   a′  and into open area  30   a.  Thus, a more precisely definable slip joint is provided. 
         [0023]    Still other configurations are possible and contemplated herein.  FIG. 2B  shows another alternative embodiment of a bracket  20   b  including a fastener F four-way locator portion  22   b  and a slip plane portion  24   b  defined by a top edge  26   b  and a tunable cross-member  32   b.  As shown, cross-member  32   b  is configured whereby space  30   b  defines a pentagonal configuration, with the apex  34  of the pentagon and so the narrowest portion of cross-member  32   b  being adjacent to the aperture defined to receive fastener F. As described for  FIG. 2A , a thickness of this portion may be altered as desired to provide a cross-member  32   b  that will rupture only on application of a force equaling or exceeding a predetermined impact load. In the depicted embodiment, depending arms  28   b,    28   b′  also include stress risers  36 ,  36 ′, which are cutouts defined in the material of arms  28   b,    28   b′  that by their shape and placement focus impact stress in a vertical load direction. 
         [0024]      FIG. 2C  shows yet another alternative embodiment of a bracket  20   c  including a fastener F locator portion  22   c  and a slip plane portion  24   c.  In this embodiment, rather than a single open space defined in bracket  20   c  between cross-member  32   c  and component C, two open spaces  30   c,    30   c′  are provided. As will be appreciated, this bracket embodiment is closer in configuration to a solid bracket, and so could be considered for implementation in situations where a more robust bracket is required to provide slippage only on application of a greater impact load. 
         [0025]      FIG. 2D  shows still another alternative embodiment of a bracket  20   d  including a fastener F locator portion  22   d  and a slip plane portion  24   d.  Here, cross-member  32   d  defines a greater thickness dimension than, for example bracket  20   a  of  FIG. 2A , and so a more robust bracket  20   d  is described requiring a greater impact load in order to provide a slip joint function. 
         [0026]      FIG. 2E  shows still yet another alternative embodiment of a bracket  20   e  including a fastener F locator portion  22   e  and a slip plane portion  24   e.  As shown, rather than a closed cross-member  32  as depicted for the embodiments of  FIGS. 2A-2D , a portion of cross-member  32   e  is open, and a “keyhole” or substantially triangular configuration is provided to open space  30   e.  That is, a gap  38  is defined at a bottom portion of the aperture defined for fastener F. As will be appreciated, on application of an impact force directly or indirectly to component C, fastener F will slip through gap  38  and a slip joint will be provided whereby component C will be allowed to slip in the direction of the depicted arrow. By providing a gap  38  of a predetermined width dimension, it is possible to narrowly define the impact load that will cause the described slippage. 
         [0027]      FIG. 3  depicts vehicle components C, C′ secured to one another by a fastener F using a bracket  20  according to the present disclosure. As described above, a direct or indirect impact to component C will impart an impact force to bracket  20  in the direction of the depicted arrows. By use of the brackets  20  as described above, it is possible to narrowly define a predetermined impact load that will cause the bracket  20  to function as a slip joint, i.e. to provide the described slippage along open space  30  and so absorb a portion of the force of impact. 
         [0028]    Thus, by the foregoing descriptions it will be appreciated that a bracket is provided including a four-way fastener locator allowing precise positioning of a fastener and also of vehicle components fastened thereby. In turn, the described brackets provide also the advantage of a slip joint allowing slippage at a desired impact load, allowing peak loads at impact to be mitigated/reduced. 
         [0029]    Obvious modifications and variations are possible in light of the above teachings. All such modifications and variations are within the scope of the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.