Abstract:
A connector apparatus includes a fastener, upper and lower vibration dampers, and a retainer. Passages in the upper and lower dampers are receivable in alignment with corresponding apertures in a pair of upper and lower parts to be interconnected. The fastener has a head and a screw-threaded stem. The stem is receivable through the aligned passages and apertures to fasten the upper and lower dampers together with the upper and lower parts upon engagement of a nut on the stem. The retainer is configured to interconnect the fastener and the lower damper releasably with the upper damper in a preliminary arrangement prior to engagement of a nut on the stem.

Description:
TECHNICAL FIELD  
         [0001]    The invention relates to connectors that damp vibrations between interconnected parts.  
         BACKGROUND  
         [0002]    Parts that vibrate relative to each other may be fastened together by vibration dampers to reduce the transmission of vibrations between the parts. For example, a vehicle body is fastened to the vehicle frame by body mounts. The mounts comprise dampers that reduce the transmission of vibration from the vehicle suspension and frame upward to the body.  
           [0003]    A vehicle body mount assembly typically includes upper and lower mounts, each of which has an elastomeric portion for damping vibrations. A screw-threaded fastener extends through aligned passages in the upper and lower mounts, and further through aligned apertures in the frame and body to clamp the frame, the body, and the mounts together upon tightening of a nut onto the fastener.  
         SUMMARY OF THE INVENTION  
         [0004]    In accordance with the invention, a connector apparatus includes a fastener, upper and lower vibration dampers, and a retainer. Passages in the upper and lower dampers are receivable in alignment with corresponding apertures in a pair of upper and lower parts to be interconnected. The fastener has a head and a screw-threaded stem. The stem is receivable through the aligned passages and apertures to fasten the upper and lower dampers together with the upper and lower parts upon engagement of a nut on the stem. The retainer is configured to interconnect the fastener and the lower damper releasably with the upper damper in a preliminary arrangement prior to engagement of a nut on the stem.  
           [0005]    A distinct feature of the invention is the retainer itself. A cylindrical portion of the retainer is receivable over the fastener stem. That portion of the retainer has a pair of opposed edges that define a seam extending fully between its opposite ends. The retainer is thus expandable by spreading the opposed edges apart to widen the seam against a spring force of the cylindrical portion. This enables the retainer to grip the stem with a return spring force upon placement of the cylindrical portion over the stem.  
           [0006]    The retainer further includes a deflectable spring tab which projects radially outward from the cylindrical portion. This enables the retainer to snap into releaseable interlocked engagement with the upper damper to suspend the fastener and the lower damper from the upper damper. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a side view, partly in section, of a vehicle body mount assembly;  
         [0008]    [0008]FIG. 2 is a view of parts shown in FIG. 1;  
         [0009]    [0009]FIG. 3 is a view of other parts shown in FIG. 1;  
         [0010]    [0010]FIG. 4 is a view showing the parts of FIGS. 2 and 3 in interconnected positions;  
         [0011]    [0011]FIG. 5 is a perspective view of a part shown in FIG. 1;  
         [0012]    [0012]FIG. 6 is a sectional view of the part shown in FIG. 5; and  
         [0013]    [0013]FIG. 7 is a cross-sectional elevational view similar to FIG. 2 and showing another embodiment. 
     
    
     DESCRIPTION  
       [0014]    The apparatus  10  shown in FIG. 1 has parts which, as described below, are examples of the elements recited in the claims. These include upper and lower vehicle body mounts  12  and  14 . The upper and lower mounts  12  and  14  support a vehicle body  16  on a vehicle frame  18  under a clamping force applied by a fastener  20  with a nut  22 . Each of the mounts  12  and  14  is constructed as a vibration damper to help isolate the body  16  from vibrations of the frame  18 .  
         [0015]    As shown separately in FIG. 2.; the upper mount  12  includes an elastomeric sleeve  30  and a metal core  32 . The sleeve  30  is a cylindrical part with a longitudinal central axis  33 . A major section  34  of the sleeve  30  has a cylindrical outer surface  36  extending axially between a pair of annular opposite end surfaces  38  and  40 . A cylindrical inner surface  50  extends fully through the sleeve  30 . A tapered, ring-shaped mounting boss  52  projects radially from the inner surface  50  near the lower end of the sleeve  30 .  
         [0016]    A metal or plastic bushing  54  is molded into elastomeric sleeve  30 , and has a horizontal annular flange  56  and a vertical cylindrical flange  58 . The bottom or outside surface of flange  56  is flush with sleeve end surface  40 , or flange  56  may extend all the way to sleeve outer surface  56 . The outer surface of vertical flange  58  is dimensioned for close reception within a circular hole in frame  18 .  
         [0017]    Bushing  54  orients mount  12  relative to frame  18 , restricts lateral movement, and resists abrasion of the elastomeric material due to relative movement between mount  12  and frame member  18 . For some purposes, and depending on customer requirements, bushing  54  may be molded into sleeve  30  as an insert so that the outer surfaces of flanges  56  and  58  are covered by a layer of the elastomeric material.  
         [0018]    The core  32  of the upper mount  12  includes a tube  60  which defines a passage  61  centered on the axis  33 . A section  62  of the tube  60  is flared radially outward. An edge  64  of the flared section  62  is crimped radially inward at the lower end of the tube  60 . A circular flange  66  projects radially outward at the upper end of the tube  60 .  
         [0019]    As further shown in FIG. 2, the elastomeric sleeve  30  is received over the metal core  32  of the upper mount  12 . When the sleeve  30  is being moved axially over the core  32  toward this position, the mounting boss  52  at the inside of the sleeve  30  is stretched and snapped over the flared section  62  of the tube  60 . The mounting boss  52  then grips the tube  60  concentrically so that the sleeve  30  is centered on the core  32 . Flange  66  on tube  60  simply rests against upper end surface  38  on elastomeric sleeve  30 , and is not bonded or otherwise secured thereto. However, for some purposes, and depending on customer requirements, upper end  38  of sleeve  30  may be adhesively bonded to the underside of flange  66 , or may be secured thereto as by molding undercut generally conical or rounded projections on upper end  38  to be snapped through suitable holes in flange  66 .  
         [0020]    The lower mount  14  and the fastener  20  are shown together in FIG. 3. Like the upper mount  12 , the lower mount  14  has an elastomeric portion  80  which is fixed to a metal portion  82 . Elastomeric portion  80  and metal portion  82  may be secured together by an adhesive bond, or by a mechanical interlock such as a roughened surface on metal portion  82  or holes therein to receive and interlock with the elastomeric material during molding. The elastomeric portion  80  of the lower mount  14  is a ring-shaped part with a pair of cylindrical inner surfaces  86  and  88  centered on an axis  89 .  
         [0021]    The metal portion  82  of the lower mount  14  is a ring with a somewhat smaller inner surface  90 . The three inner surfaces  86 ,  88  and  90  of the lower mount  14  define a passage  91  for the fastener  20 , which has a head  92  and a screw-thread stem  94 . The lower mount  14  rests on the head  92  of the fastener  20 , with the stem  94  extending upward through the passage  91 , when these parts are in the upright orientation shown in FIGS. 3 and 4.  
         [0022]    The apparatus  10  further includes a retainer  100 . As shown in FIG. 5, the retainer  100  is a generally cylindrical plastic structure with a longitudinal central axis  101 . A pair of opposed edges  102  and  104  of the retainer  100  define a seam  105  extending fully along its length. As best shown in FIG. 6, the retainer  100  has three distinct cylindrical sections  110 ,  112  and  114 , with a peripheral flange structure  116  at its upper end.  
         [0023]    The three sections  110 ,  112  and  114  of the retainer  100  have varying wall thicknesses, as shown in FIG. 6, but have a common cylindrical inner surface  118  with a uniform diameter. A flexible annular lip  120  projects inwardly from inner surface  118  at the upper end of retainer section  114  as shown in FIG. 6. The diameter of the inner surface  118  is less than the peak diameter of the screw thread on the fastener stem  94 , and the lip  120  projects toward the root diameter of the screw thread. The retainer  100  can be expanded by spreading the opposed edges  102  and  104  apart to widen the seam  105  against a spring force of the plastic material. This enables the retainer  100  to be received over the stem  94 , as shown in FIGS. 3 and 4, and also to grip the stem  94  with a return spring force that resists sliding movement of the retainer  100  along the stem  94 .  
         [0024]    The terminal end of lip  120  may lie in a single plane or may be generally helical to match the pitch of the screw thread. The lip may be continuous except for an interruption at seam  105 , or may be a series of circumferentially-spaced lip portions. Similar types of lips or threads may be provided along the length of inner surface  118  to increase pull apart forces if so desired. All of such arrangements may be considered gripping projections that extend inwardly of inner surface  118  to grip the threads on the fastener  20 .  
         [0025]    The flange portion  116  of the retainer  100  includes four parts  122  on the upper section  114  that are spaced apart from each other circumferentially about the axis  101 . The circumferential spacing between these parts  122  is defined by the seam  105  and by three parallel slots  125  that extend axially downward from the upper end  126  of the retainer  100 . Each part  122  is folded back along its length so as to extend axially downward and radially outward from the upper end  126 , and is thus configured as a radially flexible spring tab with an outer edge  128 .  
         [0026]    The parts of the apparatus  10  that are shown in FIG. 1 are interconnected with each other by first placing the upper mount  12  on the vehicle frame  18  as shown in FIG. 2. The vertical cylindrical portion  58  of bushing  54  is received closely through a circular aperture  130  in the frame  18 . The annular surface  40  of the sleeve  30  and the underside of busing flange  56  overlie the frame  18  about the aperture  130 . The lower mount  14 , the fastener  20  and the retainer  100  are then moved upward from beneath the frame  18  and into engagement with the upper mount  12 .  
         [0027]    Specifically, the fastener stem  94  is moved upward into the passage  61  in the tube  60 . The retainer  100  is carried upward into the passage  61  by the stem  94 . As the retainer  100  enters the passage  61 , the spring tabs  122  are cammed radially inward by the crimped lower edge  64  of the tube  60 . The spring tabs  122  snap radially back outward above-the crimped lower edge  64  to block removal of the retainer  100  downward from the tube  60 . The retainer  100  then suspends the fastener  20  and the lower mount  14  from the upper mount  12  in the preliminary, partially installed arrangement in which those parts are shown together in FIG. 4. The fastener  20  and the lower mount  14  are thus restrained from falling beneath the frame  18  until they can be advanced upward into the fully installed arrangement of FIG. 1.  
         [0028]    Next, the vehicle body  16  is placed over the frame  18 , with a circular aperture  132  in the body  16  centered or nearly centered over the upper mount  12 . The fastener stem  94  is advanced upward through the upper mount  12  and the aperture  132  for engagement with the nut  22 . The head  92  of the fastener  20  moves into abutment with the lower end  134  of the retainer  100  and pushes the retainer  100  upward from the flared section  62  into the narrower body of the tube  60 . The spring tabs  122  are then lifted from the crimped lower edge  64 , but continue to restrain downward movement of the fastener  20  because they are compressively engaged radially between the stem  94  and the tube  60 , and also because their outer edges  128  tend to jam against the tube  60  if pulled downward.  
         [0029]    The fastener  20  also carries the lower mount  14  upward. The cylindrical portion  58  of bushing  54  on the upper mount  12  is then received closely within the passage  91  in the lower mount  14 , with the cylindrical outer surface of bushing cylindrical portion  58  adjoining the cylindrical inner surface  86 . As the nut  22  is tightened onto the stem  94 , it draws the fastener  20  and the lower mount  14  upward. This causes the adjoining portions of the elastomeric parts  30  and  80  to become compressively loaded and deflected axially between the frame  18  and the metal ring  82  at the bottom of the lower mount  14 . The flared section  62  of the tube  60  is then received in the passage  91 . The nut  22  is fully tightened when the crimped lower edge  64  of the tube  60  abuts the top side of the metal ring  82 .  
         [0030]    In addition to supporting the fastener  20  and the lower mount  14  during installation, as described above, the retainer  100  can also support the fastener  20  and the lower mount  14  in a releaseably interconnected relationship with the upper mount  12  during shipping and handling of those parts separately from the vehicle parts  16  and  18 . This is because the retainer  100 , when interconnected with the mounts  12 ,  14  and the fastener  20  in the preliminary arrangement shown in FIG. 4, will hold them together even if the upper mount  12  has not first been placed on the vehicle frame  18 . The fastener  20  can be withdrawn from the retainer  100  by pulling it axially outward forcefully enough to overcome the grip of the retainer  100 , but can be withdrawn more easily by pulling and rotating it counterclockwise so that the screw-thread on the stem  94  will slide against the inner surface  118  of the retainer  100  and the lip  120  or other gripping projections as though the stem  94  were being unscrewed from the retainer  100 .  
         [0031]    [0031]FIG. 7 shows another arrangement wherein elastomeric sleeve  30   a  has a plurality of axially extending bores  31 ,  33  circumferentially-spaced equidistantly therearound. In the arrangement shown, there were twelve bores provided. However, the number of bores and their diameter will vary with the size of the vibration damper and with customer requirements.  
         [0032]    The bores  31 ,  33  provide a way to vary the spring rate of the damper. In FIG. 1, the spring rate is varied by changing the radial spacing between the inner surface  50  of the elastomeric sleeve and the outer surface of the tube  60 . In general, the arrangement of FIG. 1 provides a stiffer damper than the arrangement of FIG. 7.  
         [0033]    The other aspects of the embodiment of FIG. 7 generally correspond to the embodiment of FIG. 1. In FIG. 7, the core  32   a  has a cylindrical tube  60   a , a flange  66   a  and a longitudinal axis  33   a . Passage  61   a  in tube  60   a  receives the screw and retainer of FIG. 1. Bottom portion  62   a  of tube  60   a  may be a necked-in portion or may be a separate tube having a smaller diameter than tube  60   a  and welded thereto to provide an internal circumferential shoulder  63  against which the outer edges  128  of spring tabs  122  abut to hold the retainer within tube  60   a . The bushing  54   a  generally corresponds in structure and function to the bushing  54  in FIGS. 1, 2 and  4 .  
         [0034]    This written description uses examples to disclose the invention, including the best mode, and also to enable a person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.