Abstract:
A connection joint employs a first piece defining a protruding boss and a threaded hole. A second piece resides over the first piece and has a through hole that corresponds to the boss and aligns with the hole in the first piece. A bevel at the end of the second piece is utilized to initially contact the boss during installation of the second piece over the first piece. The second piece biases and then snaps into place to permit a tight and secured fit of the second piece on the first piece. A third piece that lies upon the second piece, the third piece defining a third hole that is aligned with the first and second holes. In aligning the hole of the third piece with that of the first and second, the third piece may abut the boss. A threaded screw through the holes holds the three pieces together.

Description:
FIELD 
       [0001]    The present disclosure generally relates to a snap fitting to join parts. More specifically, the present disclosure relates to a snap fitting that is used in conjunction with a screw to join parts. 
       BACKGROUND 
       [0002]    The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. Instrument clusters of automobiles generally include a plurality of gauges for displaying operational information such as vehicle speed, engine RPM, engine temperature, fuel level and other information related to driving or vehicle conditions. Many of such gauges are analog and typically include an assembly of a multitude of parts including, but not limited to: a faceplate; inner, outer and upper window plates; and various other intermediary components that ultimately mount to a case located at the rear of the assembled gauge structure. While such gauge assemblies have generally proven satisfactory for their applications, each is associated with its share of limitations. 
         [0003]    One limitation of current gauge assembly structures involves maintaining connection of a limited number of gauge parts of an intermediate assembly before a subsequent assembly of additional parts to arrive at the overall or complete gauge assembly. What is needed then is a device that permits an intermediate assembly of parts to maintain is intermediate assembled structure before the assembly of additional parts. 
       SUMMARY 
       [0004]    A connection joint, such as may be used in construction of an automotive instrument panel, joins pieces together. A first piece, such as a rear case, defines a projection such as a rectangular boss and a threaded through hole. A second piece defines a rectangular first hole within which the projection may reside while a bevel on the second piece facilitates biasing of the second piece during installation of the second piece over the boss. Upon biasing of the second piece over the first piece, the second piece lies securely snapped in place against the first piece so as not to become dislodged from the first piece. The projection may or may not protrude above the second piece when the second piece is installed upon the first piece. 
         [0005]    The first piece may further define a second hole, which may be threaded and be in alignment with the first hole of the second piece. A third piece defining a third hole that aligns with the first and second holes may lie upon the second piece when the third piece is installed over the second piece. A threaded screw with a head may pass through the first, second and third holes to secure the first, second and third pieces as a secured joint. 
         [0006]    Because the first and second pieces fit together with a snap connection, the two piece connection joint may be maneuvered into any position without risk of the joint failing and the first and second pieces coming apart. The integrity of the two piece snap fitting permits movement of the intermediate assembly to a final assembly location where the third piece may be screwed onto the intermediate assembly as the threaded screw engages the threads of the second hole of the first piece. The three pieces may be secured against the screw head. 
         [0007]    Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0008]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
           [0009]      FIG. 1  is a perspective view depicting a vehicle interior; 
           [0010]      FIG. 2  is an exploded view depicting an assembly of components of a vehicle gauge; 
           [0011]      FIG. 3  is a perspective view of a screw boss on a gauge case of a gauge assembly; 
           [0012]      FIG. 4  is a perspective view of a screw tab on an upper window plate of a gauge assembly; 
           [0013]      FIG. 5  is a perspective view of a boss tab on an outer window plate of a gauge assembly; 
           [0014]      FIG. 6  is a cross-sectional view of initiation of a connection of the boss tab of the outer window plate and the screw boss of the case; 
           [0015]      FIG. 7  is a cross-sectional view of a connection of the screw tab of the upper window plate, the boss tab of the outer window plate, and the boss of the case; and 
           [0016]      FIG. 8  is a cross sectional view of a connection of the screw tab of the upper window plate, the boss tab of the outer window plate, and the case. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
         [0018]    With initial reference to  FIG. 1 , depicted is a vehicle  10 , such as an automobile, having a dash  12  and an instrument cluster  14 , both of which may be situated in front of a driver&#39;s seat  16  in the interior cabin  18  of the vehicle  10 . As part of the instrument cluster  14 , a viewed component  20  is depicted. The viewed component  20  may be exemplified by a speedometer, and also may be herein referred to as a gauge or indicating instrument. It is appreciated that the viewed component  20  may be exemplified by other gauges, dials or instruments such as, but not limited to, tachometers, fuel gauges, temperature gauges, oil pressure gauges, etc. 
         [0019]    Turning now to  FIG. 2 , a partial exploded view of the viewed component  20  is depicted.  FIG. 2  is referred to as a partial exploded view because only specific connecting parts of an upper window plate  22 , outer window plate  24  and a case  26  are generally depicted. However, between the upper window plate  22  and outer window plate  24 , separate and additional parts such as a speedometer ring and tachometer ring may be employed. Such parts may be installed over the speedometer area  28  and tachometer area  30  of the outer window plate  24 . 
         [0020]    Similar to parts residing between the upper window plate  22  and outer window plate  24 , a multitude of separate and distinct parts also may reside between the outer window plate  24  and the case  26 . Such parts may be: speedometer and tachometer glass fronts, fuel and temperature gauge glass fronts, a mid glass front, an inner window plate, a center dial, minor and major LCDs, small and large LCD diffuser prisms, a bulb reflector, minor dials for the speedometer and tachometer, bulb reflectors for the speedometer and tachometers, computer assemblies for the speedometer and tachometer, pointer assemblies for corresponding speedometer, tachometer, fuel and temperature dials, prisms and prism covers for the speedometer and tachometer, and a backlighting prism. 
         [0021]    Continuing with  FIG. 2 , upon the case  26 , connection points  32  are depicted that correspond to boss tabs  34  on the outer window plate  24 . Although multiple connection points  32  are depicted on  FIG. 2 , only one will generally be referred to through the description of the present teachings of the invention, as each location of a connection point is generally the same. Continuing briefly with reference to  FIG. 6 , the boss tab  34 , when forced, passes over and becomes situated upon a boss  36  of the case  26  such that the boss tab  34  encompasses the boss  36  to the extent that the boss  36  protrudes through the hole  38  of the boss tab  34 . Continuing with  FIG. 3 , which is an enlarged view of a connection point  32  near the top of the case  26 , the case  26  has a threaded hole  40  that passes through a wall or surface  46  of the case  26 . The boss  36  is situated adjacent to the hole  40  such that the boss  36  may have a curved or concave surface  42  in it to provide clearance for a screw  44  ( FIG. 4 ). 
         [0022]    As depicted in  FIG. 3 , the concave surface  42  may follow the contour of the hole  40  to accommodate the screw  44 . The boss  36  and hole  40  lie on or in a surface  46  of the case  26  that also permits the boss tab  34  to lie flat on the surface  46  upon completion of installation of the boss tab  34 . With reference to  FIG. 5 , the outer window plate  24  may have ribs  48  to provide support to the boss tab  34 , such as during installation of the outer window plate  24  when the boss tab  34  may experience bending. More specifically, the ribs  48  provide support to the boss tab  34  at the end of the boss tab  34  closest to the ribs  48 , such as at location  50  of the boss tab  34 . Furthermore, the ribs  48  provide rigidity to the corners  52 ,  54  of the boss tab  34  that are proximate to the case  26 , where such boss tab  34  may be prone to cracking in the absence of such ribs  48 . 
         [0023]    Installation of the boss tab  34 , and on a larger scale the outer window plate  24 , onto the case  26  will now be described. First, with reference to  FIG. 2 , the outer window plate  24  is positioned in front of the case  26  as depicted such that the boss tabs  34  of the outer window plate  24  are in alignment with the connection points  32  of the case  26 . The outer window plate  24  is then moved toward the case  26  in accordance with arrow  55  ( FIGS. 2 and 6 ) such that the tab  56  and hole  58  of the case  26  are aligned with the tab  60  and hole  62  of the outer window plate  24  such that the tabs  56 ,  60  may be secured with a screw (not shown) to secure the surfaces of the tabs  56 ,  60  together. As the holes  58 ,  62  of the tabs  56 ,  60  are aligned, the boss tab  34  of the outer window plate  24  approaches the boss  36  of the case  26 . The boss tab  34  may have a bevel  64  on its end to direct the boss tab  34  over the boss  36  so that the boss tab  34  may “snap” over the boss  36  to permit the boss  36  to reside within the hole  38  of the boss tab  34 . When the boss tab  34  biases upward to permit the boss  36  to slide under the boss tab  34  during installation of the outer window plate  24 , the ribs  48  provide strength to the connection of the boss tab  34  to the outer window plate  24  and promote stress and flexure at area  66  of the outer window plate  24 . Without the ribs  48 , stress due to flexure may occur at corners  52 ,  54  which may promote cracking of the outer window plate  24 . As there are no sharp corners at area  66 , the upward bending is consistent, while the resiliency of the plastic permits the boss tab  34  to return to its un-flexed location and reside around the boss  36  upon completion of installation of the outer window plate  24 , as depicted in  FIG. 7 . 
         [0024]    With the boss tab  34  securely snapped into place around the boss  36 , the outer window plate  24 , case  26  and all parts residing in between, may be manipulated before the installation of any additional parts. Thus, an advantage of the snap fit of the outer window plate  24  to the case  26  is that such a sub-assembly may be freely moved, without disruption or dislocation of any parts thus assembled, before further assembly of other parts to both, the outer window plate  24  and the case  26 . 
         [0025]    With the assembly of the outer window plate  24  to the case  26 , the installation of the upper window plate  22  may then be accomplished. With reference first to  FIG. 2 , when the upper window plate  22  is installed, it secures over the boss tabs  34  of the outer window plate  24 . More specifically, and with reference to an individual instance of the screw tab  68  using  FIGS. 7 and 8 , the screw tab  68  of the upper window plate  22  may be positioned over the boss tab  34  of the outer window plate  24  in accordance with directional arrow  70  of  FIG. 7 . When the screw tab  68  of the upper window plate  22  is in position, the hole  72  through the screw tab  68  aligns with the hole  38  through the boss tab  34  and the hole  40  through the case  26 . With the holes  72 ,  38 ,  40  in alignment, the screw  44  may be installed in the holes  72 ,  38 ,  40  to secure the upper window plate  22 , outer window plate  24  and case  26  together. Regarding the screw  44 , threads  74  on the shaft  76  permit the case  26  to be drawn toward the head  77  of the screw  44  as the screw  44  is turned. Thus, the hole  40  of the case  26  may have corresponding threads. Additionally, the holes  72 ,  38  of the screw tab  68  may also have threads, although they are not required to secure the structure, but may provide added strength and reduce movement between the parts  22 ,  24 ,  26 . An advantage of securing the upper window plate  22 , outer window plate  24  and case  26  using a screw  44  with corresponding threads in at least the case  26  is that a connection of parts  22 ,  24 ,  26  free of rattles may be created. 
         [0026]    With further reference to  FIGS. 7 and 8 , the boss  36  is depicted as rising above the surface of the boss tab  34 . There are at least two advantages to such a structure. One advantage is that the boss tab  34  will be more securely positioned around the boss  36  in proportion to the extent that the boss  36  protrudes beyond a top surface of the boss tab  34 , thus lowering the possibility that the boss tab  34  might dislodge from the boss  36 . However, because the outer window plate  24  is also secured with tabs  56 ,  60  and an accompanying fastener, such as a screw, the boss  36  and accompanying boss tab  34  create a secure snap fit. 
         [0027]    Another advantage is that with a protruding portion  78  of the boss  36  protruding slightly above the surface of the boss tab  34 , the installation of the upper window plate  22  may be easier than without the protruding portion  78 . Such is the case because the screw tab  68  contacts the protruding portion  78  of the screw boss  36  to perfectly align holes  72 ,  38 ,  40  to make installation of the screw  44  easier. Such automatic alignment of the holes  72 ,  38 ,  40  before screw insertion speeds assembly time as opposed to a situation where the hole  72  has to be aligned in a more time consuming manual manipulation, such as without the protruding portion  78  of the boss  36 . 
         [0028]    Upon successful completion of the connection joint  84  as depicted in  FIG. 8 , additional advantages of the teachings of the invention become evident. For instance, with reference to  FIG. 3 , the case  26  has a first wall  80  and a second wall  82  between which the boss tab  34  and the screw tab  68  reside when in their respective installed positions over and adjacent the boss  36 . When the boss tab  34  and screw tab  68  are installed, a close tolerance exists between the parts  34 ,  68  and the first wall  80 . Because of the close tolerance between the tabs  34 ,  68  and the first wall  80 , the connection joint  84  is held in its as-connected position, that is, no part of the finished joint  84  is permitted to rotate because of the first wall  80 . Similarly, the second wall  82 , on the opposite side of the connection point  32  as the first wall  80 , performs a similar function. Although the second wall  82  is not as close to being perpendicular to the surface  46  as the first wall  80 , the second wall  82  also prevents rotation or movement of the connection joint  84  ( FIG. 8 ). 
         [0029]    Continuing with advantages of the invention and with reference to  FIG. 3 , the boss  36  is depicted as being predominantly rectangular with a semi-circular or concave surface  42  that lies immediately adjacent to, or creates an uninterrupted transition with the hole  40 . An advantage of such a boss  36  is that when the boss tab  34  is forced over the boss  36 , the rounded or square corners of the hole  38  ( FIG. 5 ) fit snugly around the rounded or square corners of the boss  36  to prevent rotation or other movement of the boss tab  34  on the boss  36 . Such a structure assures a snug and rattle-free joint  84  that is further assured by the installation of the screw  44  through holes  72 ,  38 ,  40  of the joint  84 .