Patent Publication Number: US-2015086265-A1

Title: Serviceable aligning and self-retaining elastic arrangement for mated components and method

Description:
FIELD OF THE INVENTION 
     The invention relates to components to be mated together and, more particularly, to a serviceable alignment and self-retaining elastic arrangement for mated components, as well as a method of retaining such components to each other. 
     BACKGROUND 
     Currently, components which are to be mated together in a manufacturing process are subject to positional variation based on the mating arrangements between the components. One common arrangement includes components mutually located with respect to each other by 2-way and/or 4-way male alignment features; typically undersized male structures which are received into corresponding oversized female alignment features such as apertures in the form of openings and/or slots. Alternatively, double-sided tape, adhesives or welding processes may be employed to mate parts. Irrespective of the precise mating arrangement, there is a clearance between at least a portion of the alignment features which is predetermined to match anticipated size and positional variation tolerances of the mating features as a result of manufacturing (or fabrication) variances. As a result, occurrence of significant positional variation between the mated components is possible, which may contribute to the presence of undesirably large and varying gaps and otherwise poor fit. The clearance between the aligning and attaching features may lead to relative motion between mated components, which may contribute to poor perceived quality. Additional undesirable effects may include squeaking and rattling of the mated components, for example. 
     SUMMARY OF THE INVENTION 
     In one exemplary embodiment, a serviceable self-retaining elastic arrangement for mated components includes a first component having at least one protrusion having a retaining rib circumferentially extending around an outer surface of the at least one elastically deformable protrusion. Also included is a second component having at least one elastically deformable beam. Further included is at least one aperture defined by the at least one elastically deformable beam, the at least one aperture configured to receive the at least one protrusion therein and having at least one aperture dimension smaller than at least one protrusion dimension, wherein the at least one elastically deformable beam is elastically deformed in an engaged condition of the at least one protrusion with the at least one elastically deformable beam. 
     In another exemplary embodiment, an elastic retaining assembly for instrument panel trim assembly of a vehicle includes a first trim component having a tubular protrusion extending therefrom, the tubular protrusion having a retaining rib circumferentially extending around an outer surface of the tubular protrusion. Also included is a second trim component having a first elastically deformable beam and a second elastically deformable beam. Further included is an aperture defined by the first and second elastically deformable beams, the aperture configured to receive the tubular protrusion, wherein at least one of the first and second elastically deformable beams is elastically deformed in an engaged condition of the tubular protrusion with the first and second elastically deformable beams. 
     In yet another exemplary embodiment, a method of retaining mated components of an instrument panel trim assembly is provided. The method includes inserting a tubular protrusion extending from a first trim component into an aperture of a second component, the aperture defined by a first elastically deformable beam and a second elastically deformable beam. The method also includes engaging the tubular protrusion with the first and second elastically deformable beam upon insertion of the tubular protrusion into the aperture. The method further includes elastically deforming at least one of the first and second elastically deformable beams upon insertion of the tubular protrusion to a fully engaged condition. 
     The above features and advantages and other features and advantages of the invention are readily apparent from the following detailed description of the invention when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features, advantages and details appear, by way of example only, in the following detailed description of embodiments, the detailed description referring to the drawings in which: 
         FIG. 1  is a perspective view of a first component of an elastic retaining arrangement; 
         FIG. 2  is a perspective view of a first embodiment of a second component of the elastic retaining arrangement; 
         FIG. 3  is a plan view of the first component and the second component in an engaged condition; 
         FIG. 4  is a cross-sectional view of the first component engaged with the second component taken along line  4 - 4  of  FIG. 3 ; 
         FIG. 5  is a perspective view of the first component engaged with a second embodiment of the second component of the elastic retaining arrangement; and 
         FIG. 6  is a flow diagram illustrating a method of retaining mated components. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
       FIGS. 1 and 2 , in combination, illustrate an alignment and retaining arrangement  10  ( FIG. 3 ). The retaining arrangement  10  comprises components configured to be engaged or mated with each other, such as a first component  12  and a second component  14 . The alignment and retaining arrangement  10  may be associated with numerous applications and industries, such as home appliance and aerospace applications, for example. In one embodiment, the alignment and retaining arrangement  10  is employed in a vehicle, such as an automobile. In an automobile embodiment, the alignment and retaining arrangement  10  may comprise an instrument panel (IP) arrangement. Various IP arrangements are contemplated, including a trim component mated to another trim component or a trim component mated directly to the instrument panel. Additionally, various emblems may employ embodiments of the alignment and retaining arrangement  10  described herein. As will be appreciated from the description herein, embodiments of the alignment and retaining arrangement  10  may be used in any application that benefits from a reduction or elimination of gaps that may result in vibration and noise or poor appearance. 
     The first component  12  ( FIG. 1 ) includes a main portion  16  having a first surface  18  that is typically a substantially planar surface. The first component  12  also includes a protrusion  20  extending from the main portion  16  in a direction relatively orthogonal from a plane that the first surface  18  is disposed in. The protrusion  20  is operatively coupled to the main portion  16  and may be integrally formed with the main portion  16 . The protrusion  20  may be formed as numerous contemplated embodiments. In the exemplary embodiment, the protrusion  20  comprises a tubular member. In another embodiment, the protrusion  20  may be a solid cylindrical member. Other embodiments include non-circular cross-sectional geometries. The preceding embodiment descriptions are merely illustrative and are not intended to be limiting of the numerous shapes that the protrusion  20  may be comprised of 
     A first embodiment of the second component  14  ( FIG. 2 ) includes a plurality of elastically deformable beams  22  that are disposed substantially parallel to each other. The plurality of elastically deformable beams  22  includes edges  24  that define at least one aperture  26 . In the illustrated embodiment, a first elastically deformable beam  28  and a second elastically deformable beam  30  are illustrated, however, it is to be understood that the precise number of beams may vary. As such, the number of apertures may vary as well. For purposes of discussion, only the first and second elastically deformable beams  28 ,  30 , as well as the aperture  26  will be described in detail. Similarly, although a single protrusion is illustrated, embodiments of the retaining arrangement  10  may include a plurality of protrusions, as will be described in detail below. 
     Referring now to  FIG. 3 , with continued reference to  FIGS. 1 and 2 , the protrusion  20  is illustrated in an engaged condition with the at least one aperture  26 . Specifically, the protrusion  20  is inserted into the at least one aperture  26 , with an outer surface  32  of the protrusion  20  in contact with a portion of the edges  24  of the elastically deformable beams  22 , namely the first and second elastically deformable beams  28 ,  30 . Contact between the edges  24  and the outer surface  32  of the protrusion  20  is ensured due to at least one dimension  34  of the protrusion  20  being greater than a width  36  of the aperture  26 , as shown in  FIG. 1 . In the illustrated embodiment, the at least one dimension  34  of the protrusion  20  refers to a protrusion diameter. In other embodiments comprising non-circular cross-sectional geometries of the protrusion  20 , the at least one dimension  34  corresponds to a length, width, or the like. To facilitate insertion of the protrusion  20  into the aperture  26 , a “lead-in,” or guide portion  99  ( FIG. 4 ) may be included. The guide portion  99  may be located on a surface of the second component  14  proximate the edges  24  of the elastically deformable beams  22 , as shown. Alternatively, the guide portion may be an angled region (not shown) spanning at least a portion of an end  38  of the protrusion  20  may be included to avoid engagement of two blunt objects, which may preclude insertion of the protrusion  20 . 
     The illustrated embodiment includes a rib  50  that extends around, and protrudes from, the outer surface  32  of the protrusion  20 . Although the rib  50  is shown to fully extend around the outer surface  32  of the protrusion  20 , it is to be appreciated that the rib  50  may be located intermittently about the circumference of the outer surface  32 . Insertion of the protrusion  20  into the aperture  26  ultimately leads to a fully engaged position of the protrusion  20 . The fully engaged position corresponds to a “snapping” of the rib  50  over a surface  52  of the second component  14  upon complete passing through the aperture  26  by the rib  50 . The fully engaged position provides a tight, fitted engagement between the protrusion  20  and the elastically deformable beams  22  that is achieved by contact interface between the outer surface  32  and the edges  24  of the elastically deformable beams  22 . Such a condition is ensured by sizing the protrusion to have a larger dimension than the width of the aperture  26 , as described above in detail. The malleability of the materials reduces issues associated with positional variance. More particularly, in contrast to a rigid insert that typically requires gaps between the insert and receiving structure at portions around the perimeter or outer surface of the insert, the elastically deformable beams  22 , and optionally the protrusion  20 , advantageously deform to maintain alignment of the first component  12  and the second component  14 , while also reducing or eliminating gaps associated with manufacturing challenges. Additionally, the fully engaged position of the first component  12  with the second component  14  provides a retaining force that reduces or eliminates the need for additional retaining features. The elastically deformable nature of the beams allows for removal of the protrusion  20  for service functions. 
     As will be apparent from the description herein, the elastically deformable beams  22  of the second component  14 , in combination with the particular orientations described above, facilitates precise alignment/location of the first component  12  relative to the second component  14  by accounting for positional variation of the retaining and locating features of the first component  12  and the second component  14  inherently present due to manufacturing processes. Additionally, the interference condition imposed between the protrusion  20  and the edges  24  of the aperture  26  provide a self-retaining force for the first and second components  12 ,  14 . The deforming beams provide a greater surface area for engagement between the components and allow a longer rib engagement for the retention of the male part to the female part. It is to be appreciated that the protrusion  20  may also be formed of an elastically deformable material. 
     The protrusion  20  of the first component  12  is positioned and engaged with the edges  24  that define the aperture  26  of the second component  14  upon translation of the first component  12  toward the second component  14 . Full engagement occurs when the rib  50  is pushed through the aperture  26 . In this way, the first component  12  is press fit into the second component  14  upon engagement of the protrusion  20  with the edges  24 . More particularly, an outer surface  32  of the protrusion  20  engages the edges  24  of the first and second elastically deformable beams  28 ,  30 . A void of material (apertures  27 ,  29 ) proximate elastically deformable beams  22  enable flexibility of the elastically deformable beams  22 , thereby facilitating deflection of the beams. The two beam embodiment illustrated provides 2-way locating of the protrusion  20 . 
     Referring now to  FIG. 5 , the second component  14  is illustrated according to an alternate embodiment. Specifically, the elastically deformable beams  22  of the second component  14  are disposed in a substantially non-parallel relationship with each other. In the illustrated embodiment, three beams are shown in a triangular configuration. In one embodiment, the elastically deformable beams are disposed at an acute angle relative to each other. As with the first embodiment of the second component  14  described above, the elastically deformable beams  22  at least partially define aperture  26 . The void of material in the form of the apertures  27 , and center aperture  26 , combined with the elastically deformable material comprising the elastically deformable beams  22 , facilitates the deformation and/or deflection of the beams upon insertion of the protrusion  20 , as described in detail above. The three beam embodiment illustrated provides four-way locating of the protrusion  20  (i.e., in an X-Y plane shown in  FIG. 1 ). As noted above, the protrusion is fully engaged upon passing of the rib  50  in a direction Z over the mating component  14 . 
     Any suitable elastically deformable material may be used to construct the elastically deformable beams  22  and the protrusion  20  for embodiments comprising an elastically deformable protrusion. The term “elastically deformable” refers to components, or portions of components, including component features, comprising materials having a generally elastic deformation characteristic, wherein the material is configured to undergo a resiliently reversible change in its shape, size, or both, in response to application of a force. The force causing the resiliently reversible or elastic deformation of the material may include a tensile, compressive, shear, bending or torsional force, or various combinations of these forces. The elastically deformable materials may exhibit linear elastic deformation, for example that described according to Hooke&#39;s law, or non-linear elastic deformation. 
     Numerous examples of materials that may at least partially form the components include various metals, polymers, ceramics, inorganic materials or glasses, or composites of any of the aforementioned materials, or any other combinations thereof. Many composite materials are envisioned, including various filled polymers, including glass, ceramic, metal and inorganic material filled polymers, particularly glass, metal, ceramic, inorganic or carbon fiber filled polymers. Any suitable filler morphology may be employed, including all shapes and sizes of particulates or fibers. More particularly any suitable type of fiber may be used, including continuous and discontinuous fibers, woven and unwoven cloths, felts or tows, or a combination thereof Any suitable metal may be used, including various grades and alloys of steel, cast iron, aluminum, magnesium or titanium, or composites thereof, or any other combinations thereof. Polymers may include both thermoplastic polymers or thermoset polymers, or composites thereof, or any other combinations thereof, including a wide variety of co-polymers and polymer blends. In one embodiment, a preferred plastic material is one having elastic properties so as to deform elastically without fracture, as for example, a material comprising an acrylonitrile butadiene styrene (ABS) polymer, and more particularly a polycarbonate ABS polymer blend (PC/ABS), such as an ABS acrylic. The material may be in any form and formed or manufactured by any suitable process, including stamped or formed metal, composite or other sheets, forgings, extruded parts, pressed parts, castings, or molded parts and the like, to include the deformable features described herein. The material, or materials, may be selected to provide a predetermined elastic response characteristic of the elastically deformable beams  22  and the protrusion  20  for embodiments comprising an elastically deformable protrusion. The predetermined elastic response characteristic may include, for example, a predetermined elastic modulus. 
     It is contemplated that the first component  12  may include a plurality of protrusions, while the second component  14  may include any number of elastically deformable beams  22 , and therefore any number of apertures  26 . In some embodiments, the elastic deformation of the plurality of elastically deformable beams  22 , and possibly the protrusions, elastically averages any positional errors of the first component  12  and the second component  14 . In other words, gaps that would otherwise be present due to positional errors associated with portions or segments of the first component  12  and the second component  14 , particularly locating and retaining features, are eliminated by offsetting the gaps with an over-constrained condition of other beams or protrusions. Specifically, the positional variance of each protrusion and/or beams is offset by the remaining protrusions or beams to average, in aggregate, the positional variance of the features. 
     Elastic averaging provides elastic deformation of the interface(s) between mated components, wherein the average deformation provides a precise alignment, the manufacturing positional variance being minimized to Xmin, defined by Xmin=X/√N, wherein X is the manufacturing positional variance of the locating features of the mated components and N is the number of features inserted. To obtain elastic averaging, an elastically deformable component is configured to have at least one feature and its contact surface(s) that is over-constrained and provides an interference fit with a mating feature of another component and its contact surface(s). The over-constrained condition and interference fit resiliently reversibly (elastically) deforms at least one of the at least one feature or the mating feature, or both features. The resiliently reversible nature of these features of the components allows repeatable insertion and withdrawal of the components that facilitates their assembly and disassembly. In some embodiments, the elastically deformable component configured to have the at least one feature and associated mating feature disclosed herein may require more than one of such features, depending on the requirements of a particular embodiment. Positional variance of the components may result in varying forces being applied over regions of the contact surfaces that are over-constrained and engaged during insertion of the component in an interference condition. It is to be appreciated that a single inserted component may be elastically averaged with respect to a length of the perimeter of the component. The principles of elastic averaging are described in detail in commonly owned, co-pending U.S. patent application Ser. No. 13/187,675, now U.S. Publication No. U.S. 2013-0019455, the disclosure of which is incorporated by reference herein in its entirety. The embodiments disclosed above provide the ability to convert an existing component that is not compatible with the above-described elastic averaging principles, or that would be further aided with the inclusion of, to an assembly that does facilitate elastic averaging and the benefits associated therewith. 
     A method of retaining mated components  100  is also provided, as illustrated in  FIG. 6 , and with reference to  FIGS. 1-5 . The retaining arrangement  10 , and more specifically the elastically deformable nature of the beams and possibly the protrusion, has been previously described and specific structural components need not be described in further detail. The method  100  includes inserting  102  the protrusion  20  into the aperture  26  of the second component  14 . The protrusion  20  is engaged  104  with the plurality of elastically deformable beams  22  upon insertion  102  of the protrusion  20  into the aperture  26 . The first and/or second elastically deformable beam is elastically deformed  106  upon insertion  102  of the protrusion to a fully engaged position or condition. 
     While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the application.