Patent Publication Number: US-2013240695-A1

Title: Bullet retaining clip assembly

Description:
TECHNICAL FIELD 
     The present invention relates generally to apparatus for mounting electro-mechanical subassemblies in motor vehicles, and more specifically relates to apparatus for efficiently securing an electro-mechanical device in the passenger area of a motor vehicle, and more particularly still, relates to the mounting of devices requiring an operator interface in the instrument panel area of a motor vehicle. 
     BACKGROUND OF THE INVENTION 
     Electro-mechanical devices enclosed within a discrete housing assembly are frequently employed in automotive applications. Such housing assemblies are typically formed of sheet metal panels interconnected by threaded fasteners. By way of example, audio system and navigation system devices are enclosed within a box-like case which is mounted within a host vehicle passenger cabin by threaded fasteners passing through openings in laterally extending mounting flanges affixed to a front plate and a rearwardly directed mounting bushing which is threadably affixed to a stud carried on the outer surface of the rear wall of a wraparound case housing panel. Typically, the shank of the stud extends outwardly through a hole disposed within a localized recess in the rear panel. The rear mounting bushing for current audio systems is typically attached by welding a threaded stud to the back wall of the wrap around and then the bushing is screwed on. 
     Another known stud design includes a threaded shank secured to the rear wall of the device case by a set nut and receiving a molded rubber, plastic or vinyl stud thereover. 
     With the molded plastic device housing, the mounting bushing can be molded as an integral part of the receiver box, eliminating two part numbers and the labor to install them. In application, the rearwardly directed stud registers with an opening in a vehicle structural support member. 
     SUMMARY OF THE INVENTION 
     These and other features and advantages of this invention will become apparent upon reading the following specification, which, along with the drawings, describes preferred and alternative embodiments of the invention in detail. 
     The present invention is preferably includes construction of a case and front plate of the housing assembly wherein both elements of the case assembly are formed of a composite of relatively rigid polymer material and electrically conductive material operable to shield the audio components (such as the circuit board subassembly and the CD player subassembly) from electrical anomalies including radio frequency interference (RFI), electromagnetic interference (EMI), bulk current injection (BCI) and electrostatic discharge (ESD). The electrically conductive material comprises substantially continuous planer sheet portions applied to surfaces of or within polymer housing assembly wall portions as discrete elements, electrically conductive paint, foil or electrostatic or vacuum deposition applied material. Alternatively, the electrically conductive material comprises a wire mesh screen which has been cut and folded to net shape and inserted within a mold cavity whereby it is effectively insert molded within the polymer based material. Preferably, the wire screen is centered within the wall portions of the case and front plate whereby electrically insulating polymer material effectively covers the wire screen, both inside and out, to prevent inadvertent grounding of the housing assembly to interior or exterior structures. A small portion of the conductive screen can be exposed in or near the mounting stud to provide a ground path the host vehicle body. 
     In the present invention, a retainer assembly is provided for affixing the case of an electro-mechanical device to adjacent motor vehicle support structure. The retainer assembly includes an elongated bullet locating pin molded of relatively hard material as an integral feature of said electro-mechanical device case and extending outwardly of said case. The bullet locating pin includes opposed parallel side walls forming an axially directed channel bifurcated by a tapered guideway and one or more inwardly facing engagement surfaces and an elongated bushing clip molded of relatively soft material. The bushing clip forms cooperating resilient arms configured for a slip-fit within said bifurcated channel straddling said tapered guideway and terminating in cooperating catch features operative, upon installation within said bullet locating pin, to self-lock with the engagement surface(s). The bushing clip arms extend radially outwardly of said locating pin side walls to form opposed, axially extending bushing surfaces operative to engage vehicle support structure. This arrangement has the advantage of employing a low cost integrated bullet locating pin with a soft bushing interface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: 
         FIG. 1 , is a rear-left perspective view of a one-piece injection molded housing case for an automotive audio system and the like illustrating an integral, one-piece mounting stud extending from a rear wall of the case; 
         FIG. 2 , is a broken, exploded, cross-sectional view of a “bullet” type rear mounting retainer assembly suitable for use with a molded housing case such as illustrated in  FIG. 1 ; 
         FIG. 3 , is a broken, cross-sectional view of the bullet mounting retainer assembly of  FIG. 2 , in a partially assembled state; 
         FIG. 4 , is a broken, cross-sectional view of the bullet mounting retainer assembly of  FIG. 2 , in a fully assembled state; 
         FIG. 4A , is a broken, perspective view of the cooperating self-engagement features of the bullet locating pin and hairpin bushing clip of  FIG. 4 , on an enlarged scale; and 
         FIG. 5 , is a cross-sectional view of the fully assembled bullet retainer assembly taken along lines  5 - 5  of  FIG. 4 . 
     
    
    
     Although the drawings represent embodiments of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated in order to illustrate and explain the present invention. The exemplification set forth herein illustrates an embodiment of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention represents an improvement of the device described and illustrated in U.S. Pat. No. 7,733,659 B2 entitled “LIGHTWEIGHT AUDIO SYSTEM FOR AUTOMOTIVE APPLICATIONS AND METHOD” to Chris R. Snider et al. and assigned to the common assignee of the present invention. The entire specification and drawings of U.S. Pat. No. 7,733,659 B2 are incorporated herein by reference. 
     The present invention can be beneficially applied in mounting many types electromechanical devices, particularly for affixing such devices to adjacent support structure in a motor vehicle. The present invention is of particular advantage in the mounting of so-called “infotainment” systems (ex. audio and navigation systems) and related electronic packages within the passenger cabin of a motor vehicle and will be described in connection therewith. 
     Referring to  FIG. 1 , a rear view of the case  10  of an audio system described in U.S. Pat. No. 7,733,659 B2 is depicted. Refer FIGS. 13, 14 and 91 of U.S. Pat. No. 7,733,659 B2. The case  10  is injection molded in a single structure of relatively rigid polymer based material, such as glass-filled polyester, glass-filled polypropylene, polycarbonate, PC/ABS and the like. Preferably, the case  10  is formed as a composite structure, with a preformed wire mesh insert molded therein operative to shield an electronic component mounted in the case  10  from electrical anomalies. 
     The case  10  has front mounting flanges  12  (one illustrated) for mounting the case  10  to a host vehicle instrument panel structure, and a rear wall  14  forming an integral rear mounting stud  16  extending outwardly therefrom. The stud  16  is elongated and has a characteristic cross or “+” shaped cross-section along its axial length. The cross-section configuration of the stud  16  has intersecting vertical and horizontal portions. The outwardmost surfaces of the vertical and horizontal portions are dimensioned to establish an interference fit within the opening of the host vehicle support member. Because the stud  16  is constructed of softer material (plastic) than the support member  198  (steel), the outer surfaces of the vertical and horizontal portions will tend to deform locally upon insertion into opening and thereby assure a tight connection. Rearwardly directed edges are configured with a sharp transition which will scarf the plastic material of the stud  16  upon any withdrawal from the opening. 
     The present invention provides improved, more robust retention of a rear case mount to the host vehicle support structure. 
     Referring to  FIGS. 2-4 , a retainer assembly  18 , adapted for mounting a rear portion of the housing or case  20  of an electromechanical device  22 , within a host motor vehicle, is illustrated. The retainer assembly  18  is affixed to and extends longitudinally rearwardly from the rear wall  24  of the case  20 . The retainer assembly  18  includes a bullet locating pin  26  which is integrally formed (molded) with the case  20  and a separately formed hairpin bushing clip  28 . The bullet locating pin  26  is formed of the same material as is the case  20  and is elongated along an axis designated X-X extending normally from the rear wall  24  of the case  20 . Preferably, the case  20  and bullet locating pin  26  are integrally formed from 16% glass filled PC/ABS material. The hairpin bushing clip  28  is separately formed, such as being injection molded of a different material which is significantly softer than the material making up the case  20  and bullet locating pin  26 . Preferably, the hairpin bushing clip  28  is formed of acetal plastic, such as Celcon M90-CA3208 presently sold by Ticona LLC. The acetal material is known commercially as POM and Celcon, inter alia., and has a lubricating property effectively eliminating potential squeak against the associated vehicle support structure. 
     As best viewed in  FIGS. 2 and 5 , bullet locating pin  26  is elongated along axis X-X, and has a generally H-shaped cross-section. The bullet locating pin  26  has parallel left and right vertically extending side walls  30  and  32 , respectively. The side walls  30  and  32  are laterally spaced apart to define a vertical aligned, axially directed channel  34 . The channel  34  is vertically bifurcated by a tapered guideway  36  extending laterally between the side walls  30  and  32 . Thus, tapered guideway  36  bisects the channel  34  into minor image upper and lower channel portions  34   a  and  34   b , respectively. Left and right spacers  38  and  40  extend laterally from left and right side walls  30  and  32 , respectively. 
     As best viewed in  FIGS. 2 and 4 , the left and right side walls  30  and  32  are generally “bullet shaped”, with a tapered or rounded leading edge  42  facing leftwardly away from the case  20 . The tapered guideway  36  extends along axis X-X and is vertically tapered at a constant angle θ. The righthandmost portion of the tapered guideway  36  transitions into opposed upper and lower ramps  44  and  46  forming inwardly facing upper and lower engagement surfaces  48  and  50 , respectively. 
     As best viewed in  FIGS. 2 ,  4  and  5 , the hairpin bushing clip  28  is shaped similarly to the side walls  30  and  32 , having elongated upper and lower arms  52  and  54 , respectively, joined at the lefthandmost end thereof by a web  56 . The hairpin bushing clip  28  has a constant thickness enabling it to be slip-fit between side walls  30  and  32 . The upper and lower arms  52  and  54  are vertically spaced by a tapered gap  58  at a constant angle θ. The hairpin bushing clip  28  is generally “bullet shaped”, with a tapered or rounded leading edge  60  facing leftwardly away from the case  20 . The upper and lower horizontal surfaces of the arms  52  and  54  define substantially parallel, opposed upper and lower bushing surfaces  62  and  64 , respectively. Adjacent the righthand portion thereof, the upper bushing surface  62  transitions into an upper ramp  66  forming an upper rightwardly facing stop surface  68 . Likewise, adjacent the righthand portion thereof, the lower bushing surface  64  transitions into a lower ramp  70  forming a lower rightwardly facing stop surface  72 . 
     Referring to  FIGS. 2 and 4A , the righthandmost ends of arms  52  and  54  define cooperating inwardly directed upper and lower tapered guide surfaces  74  and  76 , respectively forming a portion of the tapered gap  58 . The tapered guide surfaces  74  and  76 , at their respective apex, transition into generally leftwardly facing catch surfaces  78  and  80 , respectively. Cooperating engagement surfaces  48  and  50  are offset from their respective catch surfaces by an acute angle β. 
       FIGS. 2-4  illustrate a sequential series of steps involving assembling the hairpin bushing clip  28  within the bullet locating pin  26 . 
     Referring to  FIG. 2 , the hairpin bushing clip  28  is axially aligned with the bullet locating pin  26 , and then displaced rightwardly with respect thereto. Insodoing, the upper and lower arms  52  and  54  of the hairpin bushing clip  28  register with and slidably engage the upper and lower channel portions  34   a  and  34   b  of the bullet locating pin  26 . Simultaneously, the leading (lefthandmost) portion of the tapered guideway  36  penetrates the tapered gap  58 . 
     Referring to  FIG. 3 , as the above described insertion continues, the tapered guide surfaces  74  and  76  of the hairpin bushing clip  28  will initially contact the upper and lower ramps  44  and  46  of the bullet locating pin  26 , respectively. Upon further insertion, the ramping action will resiliently displace the leading end of the upper arm  52  upwardly and the leading end of the lower arm  54  downwardly. Simultaneously, the leading portions (righthandmost) of the arms  52  and  54  enter upper and lower openings  82  and  84  formed in the rear wall  24  of the case  20  adjacent the point of interconnection of the case  20  with the bullet locating pin  26 . 
       FIG. 3  illustrates the condition wherein the respective apices of the respective bullet locating pin ramp surfaces  44  and  46  and hairpin bushing clip ramp surfaces  74  and  76  are in alignment. At this point, the free ends of the arms  52  and  54  are at their maximum deflection, with the arms  52  and  54  acting as resilient beams. 
     Referring to  FIGS. 4 and 4A , assembly of the hairpin bushing clip  28  with the bullet locating pin  26  is completed when insertion is complete. At this point, the apices of the respective bullet locating pin ramp surfaces  44  and  46  pass slightly leftwardly beyond the hairpin bushing clip ramp surfaces  74  and  76 . Insoding, the natural resiliency of the material forming the hairpin bushing clip  28  affects a snap catch or engagement whereby the engagement surfaces  48  and  50  of the bullet locating pin  26  are in an abuting relationship with the catch surfaces  78  and  80  of the hairpin bushing clip  28 . Thus assembled, the hairpin bushing clip  28  cannot be withdrawn from its illustrated position without the use of a special removal tool applied inside the case  20  by a service technician. 
     Simultaneously with the above described snap-lock engagement of the hairpin bushing clip  28  with the bullet locating pin  26 , the stop surfaces  68  and  72  formed by the outwardly directed ramps  66  and  70  engage the outer surface of the rear wall  24  of the case  20  to prevent further insertion of the hairpin bushing clip  28 . 
     Referring to  FIG. 4A , the mechanism of the interlocking engagement of the hairpin bushing clip  28  with the bullet locating pin  26  is illustrated. Preferably, the engagement surfaces  48  and  50  defined by the tapered guideway  36  of the bullet locating pin  26  extend nearly vertically. By contrast, the catch surfaces  78  and  80  of the hairpin bushing clip  28  are angularly offset by an acute angle β. This ensures robust line contact between the apex of the ramps  44  and  46  and the associated catch surfaces  78  and  80 . In this condition, the arms  52  and  54  of the hairpin bushing clip  28  apply radial force, as indicated by arrow  86 , as well as axially directed forces. 
     Referring to  FIGS. 4 and 5 , the electromechanical device is installed, for example, in a host motor vehicle. Insodoing, the retainer assembly is slip-fit or slightly interference fit through a flanged opening  88  formed in design intent support structure  90  to affect a rear mounting point. It is contemplated that two or more of such retainer assemblies can be employed in a single installation. 
     Referring to  FIG. 5 , the vertical dimension of the upper and lower arms  52  and  54  of the hairpin bushing clip  28  exceed that of the side walls  30  and  32  of the bullet locating pin  26 . Thus, once installed, all loading between the electromechanical device  22  and the support structure  90  extends through the upper and lower bushing surfaces  62  and  64 . The “+” shaped cross-section structure of the bullet locating pin  26  is dimensioned to provide locating spacer functionality while avoiding direct contact with the vehicle support structure  90 , except for momentary high load or impact conditions. 
     It is to be understood that the invention has been described with reference to specific embodiments and variations to provide the features and advantages previously described and that the embodiments are susceptible of modification as will be apparent to those skilled in the art. 
     Furthermore, it is contemplated that many alternative, common inexpensive materials can be employed to construct the basis constituent components. Accordingly, the forgoing is not to be construed in a limiting sense. 
     The invention has been described in an illustrative manner, and it is to be understood that the terminology, which has been used is intended to be in the nature of words of description rather than of limitation. For example, the bushing surfaces formed by the bushing clip  28  are described in the preferred embodiment as being vertically separated. The bushing surfaces could also be horizontally separated or in other orientations without departing from the spirit of the present invention. 
     Obviously, many modifications and variations of the present invention are possible in light of the above teachings. For example, the bullet locating pin  26  can, alternatively, be fabricated separately from the case  20 , but from the same or similar material, and subsequently affixed to the case  20 . It is, therefore, to be understood that within the scope of the appended claims, wherein reference numerals are merely for illustrative purposes and convenience and are not in any way limiting, the invention, which is defined by the following claims as interpreted according to the principles of patent law, including the Doctrine of Equivalents, may be practiced otherwise than is specifically described.