Abstract:
A bezel that includes a number of unitary EMI-shield-and-snap-retention features molded onto an inner surface of a bezel. The EMI-shield-and-snap-retention features partially fasten an EMI shield to the bezel, while also fastening the bezel to a snap attached to an equipment enclosure. Each feature contains two flanged and tapered guide strips flanking one or more ramp-shaped pieces. As the EMI shield is placed flat along the interior of the bezel, the flanged sections of the guide strips lie over top of the EMI shield, pressing the EMI shield against the interior of the bezel. As the bezel closes against the equipment enclosure, the tapered sections of the guide strips guide the snap up the ramp-shaped pieces. The snap gains tension ascending the ramp-shaped pieces. When the snap crests the ramps, tension is released in the snap, causing the convex tip of the snap to stay secured to the ramp-shaped pieces.

Description:
TECHNICAL FIELD  
         [0001]    The present invention relates to bezels and electromagnetic interference (“EMI”) shields for electronic devices, and, in particular, to features that partially fasten an EMI shield to a bezel, while also securing the bezel to an equipment enclosure.  
         BACKGROUND OF THE INVENTION  
         [0002]    Typically, electronic devices are housed in standardized equipment enclosures. Many equipment enclosures include an outer housing that is supported by an inner rack. The inner rack commonly comprises a substantially rectilinear metal frame including several vertical columns, each provided with a plurality of mounting and alignment holes that permit the mounting of various components to the inner rack.  
           [0003]    Many equipment enclosures also include a removable bezel that forms an aesthetic front face for the enclosure. The bezel may also shield internal components from environmental contaminants, such as moisture and dust, as well as shield the environment from noise generated by components within the enclosure. Removing the bezel provides access to components mounted within the enclosures in order to repair, replace, inspect, and perform maintenance tasks on the components.  
           [0004]    One current method used to fasten bezels to equipment enclosures employs a snap-on fastening mechanism. A snap-on design generally incorporates a series of snaps, which are either spaced around the edge of the front face of an equipment enclosure or around the perimeter of the interior lip of the bezel. Each snap is fastened to a corresponding retention-apparatus on the interlocking surface.  
           [0005]    Many snap-on designs employ a series of retention-features, on the surface of the bezel, for snap retention. Each retention-feature must be molded as part of the bezel. Thus, every additional feature increases mold complexity and tooling-time expense. Consequently, molded bezels incorporating a snap-on fastening mechanism are expensive and time-consuming to manufacture.  
           [0006]    Many electronic components generate electromagnetic radiation in the radio frequency (“RF”) portion of the electromagnetic spectrum. RF-radiation generated by electronics is a common source of environmental electromagnetic interference (“EMI”) that may degrade or impair operation of other electronic devices and circuits exposed to the RF-radiation. Increased use of electronic devices, especially mobile electronic devices, such as cellular phones, has increased environmental EMI levels. Consequently, EMI shields have been incorporated into equipment enclosures to block EMI from interfering with components within equipment enclosures, as well as to shield the environment from EMI generated by components within the enclosure.  
           [0007]    Currently, many EMI shields are semi-permanently attached to bezels using fasteners and expensive and time-consuming post-mold heat-taking steps during the manufacturing process. In addition to EMI-shield attachment being slow and expensive, EMI-shield removal is tedious, and the risk of damage to the bezel is high. Recycling of EMI shield/bezel combinations requires the plastic bezel to be separated from the EMI shield, and is therefore expensive and time-intensive because of the semi-permanent post-mold heat-stake attachments. Attachment of EMI shields by semi-permanent, post-mold heat-staking steps also fails to provide an option for consumers to purchase a bezel assembly without a pre-installed EMI shield. Consumers purchasing electronic devices in a configuration not requiring an EMI shield must still purchase an equipment enclosure pre-assembled with an EMI shield to ensure adequate shielding for future upgrades.  
           [0008]    Thus, manufacturers, designers, and consumers of electronic devices have recognized the need for a system allowing for simple, easily detachable attachment of an EMI shield to a bezel, and a bezel to an equipment enclosure.  
         SUMMARY OF THE INVENTION  
         [0009]    In one embodiment of the present invention, one of more EMI-shield-and-snap-retention features are molded onto the inner lip of a bezel in a single mold. The snap-retention section of the EMI-shield-and-snap-retention feature comprises two guide strips and two ramp-shaped pieces that receive a snap, which is attached to an equipment enclosure. As the bezel reaches a final, flush position against the equipment enclosure, the two guide strips guide the convex tip of the snap up the ramp-shaped pieces. The ramps increase the displacement of the snap, causing a build-up of tension within the snap. When the convex tip of the snap passes over the back edge of the ramp-shaped pieces, displacement of the snap is reduced. Thus, tension is released within the snap, and the tip of the snap stays secured to the back edge of the ramp-shaped pieces.  
           [0010]    The EMI-shield-retention section of the EMI-shield-and-snap-retention feature, comprising the two guide strips, partially fastens an EMI shield to the bezel. Each guide-strip further comprises a flanged section and a tapered section. The flanged section extends along the outer edge of the inner lip of the bezel, while the tapered section extends across the inner lip, from the outer edge to the major inner surface of the bezel. As the EMI shield is placed flat along the major inner surface of the bezel, a notch, cut from one edge of the EMI shield, slides around the tapered section of the guide strips, and under the flanged section. The flanged section presses the EMI shield against the major inner surface of the bezel, thus securing a portion of the EMI shield against the bezel. Thus, the embodiment of the present invention embodies a single, molded EMI-shield-and-snap-retention feature incorporating a multiplicity of different functions, thereby reducing tool complexity and cost and improving reliability. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is a perspective view of a bezel containing an EMI-shield-and-snap-retention feature, and an equipment enclosure containing a snap.  
         [0012]    [0012]FIG. 2 is a close-up, perspective view of an EMI-shield-and-snap-retention feature molded onto the inner lip of a bezel.  
         [0013]    [0013]FIG. 3 is a perspective view of one possible snap compatible with a snap-retention section of a feature.  
         [0014]    [0014]FIG. 4A is a perspective view of a snap before climbing two ramp-shaped pieces.  
         [0015]    [0015]FIG. 4B is a perspective view of a snap after cresting two ramp-shaped pieces.  
         [0016]    [0016]FIG. 5 is a perspective view showing a snap fastened to a snap-retention section of an EMI-shield-and-bezel-retention feature.  
         [0017]    [0017]FIG. 6 is a perspective view illustrating an EMI shield fastened to a bezel, in part, by two EMI-shield-and-snap-retention features. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    In one embodiment of the present invention, shown in FIGS.  1 - 6 , one or more integrated EMI-shield-and-snap-retention features are molded onto the interior of a bezel with a single lifter. FIG. 1 is a perspective view of a bezel containing an EMI-shield-and-snap-retention feature and an equipment enclosure containing a snap. The EMI-shield-and-snap-retention feature  108  is molded onto the inner lip  110  of the bezel  112 . The snap  102 , compatible with the snap-retention section of the EMI-shield-and-snap-retention feature  108 , is shown anchored to the front face of a vertical column  104  in an equipment enclosure  106 . The snap  102  protrudes outward, away from the front face of the equipment enclosure  106 , enabling the snap  102  to fasten to the EMI-shield-and-snap-retention feature  108 . Note that the size of the snap and the EMI-shield-and-snap-retention feature are enlarged for clarity. Several EMI-shield-and-snap-retention features may be necessary to fully fasten the bezel to the equipment enclosure, depending on the size and shape of the bezel, and whether an additional type of fastening mechanism is employed. Also note that only one vertical column is shown in the equipment enclosure, for clarity of illustration. An equipment enclosure commonly includes at least three additional vertical columns.  
         [0019]    [0019]FIG. 2 shows a close-up, perspective view of an EMI-shield-and-snap-retention feature molded onto the inner lip of the bezel. The EMI-shield-and-snap-retention feature  202  comprises a snap-retention section  212 , 214 , 216 , and  218  and an EMI-shield-retention section  216 , 218 , 220 , and  222 . The snap-retention section  212 , 214 , 216 , and  218  of the EMI-shield-and-snap-retention feature  202  comprises two guide strips  208 , 210  flanking two parallel, ramp-shaped pieces  212 , 214 , or ramps. Each guide strip  208 , 210  comprises two sections, a flanged section  220 , 222  and a tapered section  216 , 218 . The two, flanged sections  220 , 222  extend along the outer edge of the inner lip  204 , before bending inward towards the major inner surface  224  of the bezel  206  along the two tapered sections  216 , 218 .  
         [0020]    The tapered sections  216 , 218  of the guide strips  208 , 210  extend across the inner lip  204  to the major inner surface  224 , creating a slightly tapered space along the inner lip  204 , and in-between the tapered sections  216 , 218 . The space tapers from the outer edge of the inner lip  204  to the major inner surface  224 , serving as a guide that corrects small misalignments between the bezel  206  and the equipment enclosure as the bezel  206  is fastened to the equipment enclosure.  
         [0021]    The two ramp-shaped pieces  212 , 214 , spaced between the two guide strips  208 , 210 , rise away from the flanged sections  220 , 222  of the guide strips  208 , 210 . The ramp-shaped pieces  212 , 214  rise from the outer edge of the inner lip  204  towards the major inner surface  224  of the bezel  206 . The tapered sections  216 , 218  of the guide strips  208 , 210  extend all the way across the inner lip  204  of the bezel  206  to the major inner surface  224  of the bezel  206 , whereas the ramp-shaped pieces  212 , 214  are shorter in length, and do not extend to the major inner surface  224 . The space present between the back edges  226 , 228  of the ramp-shaped pieces  212 , 214  and the major inner surface  224 , makes room for the tip of the snap, which fastens to the back edges of the ramp-shaped pieces when the bezel  206  is fastened to the equipment enclosure.  
         [0022]    [0022]FIG. 3 is a perspective view of one possible snap  302  compatible with the snap-retention section of the EMI-shield-and-snap-retention feature. The snap  302  comprises a notched base  304  with three screw holes  306 ,  308 , and  310 , and a flat, tapered tongue  312  extending to a convex tip  314 . The notched base  304  and screw holes  306 ,  308 , and  310  facilitate attachment of the snap  302  to a vertical column on the front face of the equipment enclosure.  
         [0023]    As the bezel is fastened to the equipment enclosure, the tapered tongue of the snap aligns with the guide strips of the snap-retention section of the EMI-shield-and-snap-retention feature. The guide strips guide the firmly anchored snap up the two ramp-shaped pieces between the guide strips. FIG. 4A is a perspective view showing the snap  402  before ascending the two ramp-shaped pieces  404 , 406 . The snap  402  is oriented so that the convex tip  408  faces the ramp-shaped pieces  404 , 406 . Ascension of the two ramps  404 , 406  causes tension to build in the snap  402  as a result of increased displacement of the tip of the snap  408  from the original projection of the snap  402  from the equipment enclosure. The convex shape of the tip  408  further accentuates the displacement and the corresponding tension. The angle of the incline of the ramp-shaped pieces  404 , 406  determines the amount of force necessary to displace the snap  402 . The steeper the angle, the more force that is necessary. Thus, the steeper the incline of the ramps, the more force required to fasten the snap  402  to the ramp-shaped pieces  404 , 406 .  
         [0024]    [0024]FIG. 4B is a perspective view showing the snap  402  after cresting the ramp-shaped pieces  404 , 406 . When the convex tip  408  of the snap  402  passes over the top of the ramp-shaped pieces  404 , 406 , the displacement of the snap  402  is significantly reduced. Consequently, tension in the snap  402  is reduced, and the convex tip  408  of the snap  402  stays secured to the back edges of the ramp-shaped pieces  404 , 406 .  
         [0025]    [0025]FIG. 5 shows the snap  502  fastened to the snap-retention section of the feature  504 . Note that the length and width of the space between the guide strips generally corresponds with the length and width of the snap  502 . Also note that several features may be necessary to fully fasten one length of the bezel to the equipment enclosure.  
         [0026]    [0026]FIG. 6 is a perspective view showing an EMI shield fastened to the bezel. Two EMI-shield-and-snap-retention features  606 , 608  are shown along the left inner lip  610  of the bezel  604 . The EMI shield  602  contains two notches  612 , 614 . Each notch  612 , 614  corresponds to the size, shape, and position of each EMI-shield-and-snap-retention feature  606 , 608  on the bezel  604 . The horizontal lengths  624 , 626 , 628 , and  630  of the notches  612 , 614  are generally the same width as the guide strips  616 ,  618 , 620 , and  622 . The vertical lengths  632 , 634  of the notches  612 , 614  are generally the distance between the guide strips  616 , 618 , 620 , and  622  at a point in-between the tapered section  636 , 638 , 640 , and  642  and the flanged section  644 , 646 , 648 , and  650  of each guide strip  616 , 618 , 620 , and  622 . The tapering of the guide strips  616 , 618 , 620 , and  622  promotes a snug fit between the notched EMI shield  602  and the bezel  604  by allowing variable positioning of the notches  612 , 614  against the guide strips  616 , 618 , 620 , and  622 , thus accounting for small variances in the EMI-shield-and-snap-retention features  606 , 608  and the EMI shield  602 .  
         [0027]    Proper placement of the EMI shield  602  on the bezel  604  requires that the edge of the EMI shield  602  containing the notches  612 , 614  slide into the inner lip of the bezel  604  containing the EMI-shield-and-snap-retention features  606 , 608 . The notches  612 , 614  slide around the tapered sections  636 , 628 , 640 , and  642  of the guide strips  616 , 618 , 620 , and  622 , and under the flanged sections  644 , 646 , 648 , and  650 , until the edge of the EMI shield  602  containing the notches  612 , 614 , contacts the inner lip of the bezel  604 . Once the EMI shield  602  is lying flat against the major inner surface of the bezel  604  and under the flanged sections  644 , 646 , 648 , and  650  of the guide strips  616 , 618 , 620 , and  622 , the EMI shield  602  becomes partially restrained. The flanged sections  644 , 646 , 648 , and  650  press the EMI shield  602  firmly against the major inner surface of the bezel  604 , thus fastening a portion of the EMI shield  602  to the bezel  604 . Note that, further attachments are necessary to fully fasten the EMI shield  602  to the bezel  604 .  
         [0028]    Although the present invention has been described in terms of a particular embodiment, it is not intended that the invention be limited to this embodiment. Modifications within the spirit of the invention will be apparent to those skilled in the art. For example, the material used to construct the EMI-shield-and-snap-retention feature and the snap may vary. Generally, the EMI-shield-and-snap-retention feature is made from the same material as the bezel. In most cases, plastic can be used. The size and number of EMI-shield-and-snap-retention features can vary depending on the size and shape of the equipment enclosure. Furthermore, the exact shapes and numbers of the different pieces of the EMI-shield-and-snap-retention feature may vary as well. For instance, a EMI-shield-and-snap-retention feature need not have exactly two ramp-shaped pieces. Moreover, the incline of the ramp-shaped pieces may vary depending on the predetermined amount of force desired to fasten the bezel to the equipment enclosure. The angle of the tapering of the guide strips may also vary. Different types of snaps may require a different guide-strip angling. Different surface locations may be used to attach the snap or EMI-shield-and-snap-retention feature. For instance, EMI-shield-and-snap-retention features may be molded to a horizontal length of the inner lip of the bezel instead of a vertical length. Additionally, EMI-shield-and-snap-retention features may be molded onto several different lengths of the inner lip of the bezel. The bezel-retention mechanism of the present invention may be used by itself, or in conjunction with other bezel-retention mechanisms, for instance, a sliding-mechanism, or a hinged-mechanism.  
         [0029]    The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the invention. The foregoing descriptions of specific embodiments of the present invention are presented for purpose of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations are possible in view of the above teachings. The embodiments are shown and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents: