Abstract:
A vehicle body mount comprised of a lower rebound mount and an upper load mount provides a method to fasten the rebound mount to the load mount in preparation for accommodation of a vehicle frame and vehicle body which may be radially eccentric mismatched. While continually maintaining the interlock function, the integral rebound mount and flexible interlock feature allows radial float of the rebound mount relative to the load mount, until the securing bolt seeks, engages, and is aligned with the body mounted nut, during assembly of the body to the frame. The rebound mount is defined by an extending interlock which is expandable at its outermost portion in order to engage the central opening of the upper load mount.

Description:
TECHNICAL FIELD 
     The present invention relates to body mounts utilized in mounting a vehicle body to a vehicle frame or chassis to assist in eliminating the transfer of vibrations from the frame to the vehicle body. 
     BACKGROUND ART 
     In the manufacturing of vehicles, it is known to mount a vehicle body to the vehicle frame in such a manner to reduce the transfer of vibration from the frame to the body. Were the vibration not reduced, the vehicle passengers would experience a high level of noise and road feel to the vibration transfer. The desired reduction is accomplished by securing the body to the flame utilizing resilient body mounts. 
     Body mounts typically comprise a load mount, which, when assembled, is located between the frame and vehicle body and a rebound mount which is mounted underneath the vehicle frame. A few typical body mounts are illustrated in U.S. Pat. Nos. 2,838,339, 3,479,081, and 3,809,427. U.S. Pat. Nos. 2,838,339 and 3,809,427 disclose two-part mounts, while 3,479,081 discloses a unitary mount for when one end of the mount is inaccessible. 
     To reduce assembly time of the vehicle, modern manufacturing includes the step of preassembling or premounting the body mount on the frame. With premounted body mounts, the assembly line workers need only insert the fastening means into the vehicle body and the mount. 
     Various methods have been employed to accomplish the desired preassembly of the body mount. U.S. Pat. No. 3,622,194 discloses a body mount with “snap action” connectors to hold the body mount in an interlocked, preassembly position. U.S. Pat. No. 4,720,075 discloses providing a tabbed washer inside of an alignment tube wherein, when the flared end of a thimble tube is inserted into the alignment tube, the tabs lock the thimble tube into a preassembly position. U.S. Pat. No. 5,170,985 discloses providing the tabbed washer integral with the thimble tube which locks with the narrowed width of the alignment tube to form a preassembly of the body mount. 
     The tab preassembly means of the above referenced patents provide for sufficient holding of the two components of the body mount; however, manufacturing and assembly of the separate components adds substantially to the cost of the mount. Additionally, the tabs can readily become damaged during manufacturing, resulting in substantial product and time loss during manufacturing. Due to the required corresponding configuration and sizing of the thimble and spacer tubes the mounts of the prior art are not applicable for preassemblies which must permit a relatively high degree of radial float between the thimble and spacer tubes due to potential misalignment of the apertures of the frame and vehicle body. 
     Furthermore, with many automotive manufacturers seeking to maximum efficiency with preassembled components, it may be required that the preassembled vehicle components are transported a substantial distance from the preassembly location to the final assembly location. Thus the preassembly must be very robust, and not come apart readily during transportation. 
     The present invention provides a body mount that is simpler to manufacture and assemble, resulting in a more cost efficient product. The inventive body mount has fewer parts that can potentially be damaged during manufacturing, assembly, and transportation, resulting in less time and material being wasted during manufacturing. The body mount permits a high degree of radial misalignment of the apertures of the frame and vehicle body. Additionally, the inventive body mount is robust, inexpensive to produce, and requires no special tools or awkward procedures to either engage, disengage, or reengage. 
     SUMMARY OF THE INVENTION 
     The present invention provides means to fasten a rebound mount to a load mount, in preparation for accommodation of a frame and load mount radially eccentric mismatch to the body fastener, most commonly a nut. While continually maintaining the interlock function, the integral rebound mount and flexible interlock feature allows radial float of the rebound mount, until the securing bolt seeks, engages, and is aligned with the body mounted nut, during assembly of the body to the frame. 
     A first aspect of the invention is a vehicle body mount comprising an upper load mount and a lower rebound mount. The load mount has an extending central opening with a shoulder portion. The rebound mount has a hollow extending interlock. At least the upper portion of the hollow extending interlock is elastically deformable. The upper portion of the interlock, when in a relaxed state, has a maximum dimension D F  less than the corresponding dimensions D O , D I  of the extending central opening. The upper portion is capable of expanding to a maximum dimension for retention of the rebound mount in the load mount 
     A further aspect of the invention is a vehicle body mount comprising an upper load mount and a lower rebound mount, the rebound being definable by a hollow extending interlock. When the upper portion of the interlock is elastically deformed, the maximum dimension of the hollow extending interlock is greater than the minimum dimension D I  of the extending central opening. A further aspect is an interlock dimensioned so that when the upper portion is elastically deformed, the maximum dimension is also less than or equal to the maximum dimension D O  of the extending central opening. 
     A further aspect of the invention is a vehicle body mount wherein the bound mount has a plurally of vanes spaced about the upper portion of a hollow extending interlock. The rebound mount preferably has three to eight vanes. 
     A further aspect of the invention employs a rebound mount where the upper portion of an extending interlock is defined by a plurality of vanes, the vanes being comprised of multiple face surfaces. The face, surfaces are the radially outer faces of the vanes and at least one of the face surfaces contacts the extending central opening of the load mount when the upper portion of the hollow extending interlock is expanded. 
     A further aspect of the invention is a vehicle body mount comprising an actuating means that is inserted into the hollow interlock after the rebound mount is inserted into the load mount. The actuating means may be either a bolt which may or may not be used for the final securing step of attaching the vehicle frame to the vehicle body or an actuating tube. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     The invention will be described by way of example and with reference to the accompanying drawings in which: 
     FIG. 1 is a cross-sectional view of the preassembled vehicle body mount; 
     FIG. 2 is a perspective view of the rebound mount; 
     FIG. 3 is a cross-sectional view of the rebound mount along line  3 — 3 ; 
     FIG. 4 is a cross-sectional view of the partially assembled body mount, 
     FIG. 5 is a cross-sectional view of an alternative preassembly of the body mount. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 illustrates a body mount  10  in a temporary interlocking configuration. The configuration permits the body mount  10  to maintain a temporary connection of the upper load mount  12  and a lower rebound mount  14  on a vehicle frame  16 . Briefly, the load mount has a central extending opening  18  into which the extending interlock  20  of the rebound mount  14  is inserted. The extending interlock  20  of the rebound mount  14  has a plurality of expansion vanes  22 . When any actuating means, such as the illustrated frame-to-body bolt  24  or an actuator tube  54  (see FIG.  5 ). is inserted into an elevation of the vanes  22 , the upper portion of the extending interlock  20  expands radially outward, causing the vanes  22  to interact with the opening  18 . This expansion maintains the body mount  10  in the illustrated interlocking configuration. 
     The pre-interlock insertion of the rebound mount  14  into the load mount  12  requires only a minimal force that is equal to the weight of the rebound mount  14 . For a typical sized mount  10 , this insertion force is not more than 5 lbs f . Once the vanes  22  are expanded, a retention force greater than ten times the weight of either the load mount  12  or the rebound mount  14  is generated. 
     The rebound mount  14 , seen illustrated in FIGS. 2 and 3, is predominately a resilient element which is capable of elastically deforming. Extending along the base of the mount  14  is a reinforcing rigid plate  26 . The reinforcing plate  26 , in its primary embodiment, has a circular configuration with a central opening. Preferably, the plate  26  is a rigid material, for example, steel plate. The lower portion of the extending interlock  20  may also be formed from a rigid material, so long as the upper portion of the interlock  20 , including the vanes  22 , are formed of a resilient material which is capable of.elastically deforming. 
     The extending interlock  20  extends from the central portion of the rebound mount  14 . The extending interlock  20  has a hollow central portion  28  through which the actuating means, herein, the bolt  24 , passes. The top portion of the extending interlock  20  is defined by the plurality of expansion vanes  22 . The vanes  22  are defined by three surface faces prior to preassembly, as seen in FIGS. 2 and 4. The first face  30  is inclined away from the main portion  36  of the extending interlock  20 , with the second face  32  extending from the first face  30 . The first face  30  has an inclination angle relative to the main portion  36  of the extending interlock  20 . The second face  32 , in its primary embodiment, is nominally parallel to the main shaft portion  36 . The third face  34  is inclined away from the second face  32  at an angle β. The first face inclination angle is within the range of 90° to 150°, with a preferred range of 120° to 150°; the third face inclination angle B is within the range of 15° to 40°, with a preferred range of 20° to 30°. 
     The extending interlock  20  is illustrated with five expansion vanes  22 ; however, the number of vanes  22  may vary from a minimum of three and may even have more than eight vanes. The primary limitations on the number of vanes  22  are the resiliency of the material which forms the upper portion of the extending interlock  20  and the ability of a minimum number of vanes  22  to interact with the extending opening to maintain the preassembled position. Prior to expansion of the vanes  22 , the greatest dimension of the top portion of the extending interlock is D F . 
     The hollow central portion  28  of the extending interlock  20  has a varying internal diameter, see FIG.  4 . The lower interlock portion has a fixed internal diameter, D L . The internal diameter decreases coincident with the beginning of the inclination of the first face  30  of the vanes  22 . The diameter decrease terminates above the axial location of the juncture of the second  32  and third  34  vane faces. The diameter decrease results in an inclination angle μ relative to the lower interlock portion. The upper internal diameter D U  of the extending interlock  20  is approximately 40% to 70% of D L . The vanes  22  have a radial thickness t, see FIG.  3 . that is variable and quantified as a result of the result of the quantitative descriptions of D F . D U , μ, and β. 
     The load mount  12 , illustrated in FIG. 4, is a composite of rigid and resilient portions. The rigid portion  38  has a cap shaped portion beginning at the flange  40 , which extends axially and then radially to form the top surface  42  of the mount  12 . The rigid portion  38  then extends into the load rubber  13 . forming the central extending opening  18 . As the opening  18  extends through load mount  12 , the diameter of the opening  18  decreases. The diameter decrease occurs over a limited length, forming a shoulder  44 . The lower portion  46  of the central opening  18  extends past the load rubber  13 . A rigid ring  47 , as illustrated may reinforce the load rubber  13 . Both the ring  47  and the rigid portion  38  are preferably formed of a rid material, for example, steel. The outer portion of the opening  18  has a diameter D O , and the inner portion has a diameter D I . The inner diameter D I  is 80-95% of D O . 
     FIG. 4 illustrates the body mount  10  prior to preassembly. The load mount  12  is located over the aperture  48  of the vehicle frame  16 , with the lower portion  46  of the central opening  18  aligned to extend into the aperture  48 . The rebound mount  14  is brought into place below the vehicle frame  16  and aligned with the central aperture  48  and the lower portion  46  of the central opening  18 . The load and rebound mounts  12 ,  14  are brought towards one another until the load rubber  13  and the rebound rubber  15  of the respective mounts  12 ,  14  contact the vehicle frame  16 , and the end of the lower portion  46  is at a performance defined distance from the central portion of the rebound mount  14 , as seen in FIGS. 1 and 5. At any time after the vanes  22  of the rebound mount  14  have axially extended above the shoulder  44  of the central opening  18 , the bolt  24  may be pushed into the opening  28  to force the radial expansion of the vanes  22 . 
     Since the bolt  24  has a diameter greater than the decreasing diameter portion of the interlock  20  and the upper shaft portion diameter D U , and the interlock.  20  is formed of a resilient material, the upper portion of the interlock  20 , and the vanes  22 , expand radially outward, see FIG.  1 . At least one of the surface faces  30 ,  32 ,  34  that define the vane  22  contacts the wall of the opening  18 . The final outermost diameter of the vanes is greater than inner diameter D I  of the central opening  18 , but less than, or equal to, the outer diameter D O  of the opening  18 , the difference in diameters may be defined as the measurement x. This, and the radial deformability of the vanes  22 , creates a flex-float amount y. The flex-float amount y is also the difference between the shaft diameter D S  and the inner diameter D I . The flex-float amount y permits the rebound mount  14  and fastener  24  to be able to move laterally relative to the rebound mount  12  and the chassis frame  16 . The flex-float amount y allows the rebound mount  14  and the fastener  24  to be realigned to the fixed, or floating, body fastener  50 . 
     The misalignment, z, of the frame aperture  48  to the body fastener  50  is a function of the tolerances associated with each independent frame or body subassembly, and most commonly may add up to 3 or more millimeters in radial misalignment, at any of up to 10 specific locations required to attach the vehicle body  52  to the vehicle frame  16 . When the fastener  24  is driven upward into the rebound mount  14 , the fastener  24  passes through the extending interlock  20  of the rebound mount  14  and seeks the offset body fastener  50 . The flexibility of the vanes  22  allow for minimal side load on the fastener  24 . 
     FIG. 5 illustrates the assembled mount employing an alternate method of preassembly for the interlocking mount  10 . Instead of using the bolt  24  to expand the vanes  22 , a temporary actuator tube  54  is employed. The actuator tube  54  has a diameter substantially equivalent to the internal shaft diameter D L . The tube  54  is illustrated with a tapering tip  56  for the purpose of providing a smooth interference between the tube  54  and the extending interlock  20 . The tube  54  may have a height greater than the extending interlock  20 , longer than the illustrated length. The temporary tube  54  is used in the same manner as the bolt  24 , except that prior to final assembly of the vehicle body  52  to the vehicle frame  16 , the bolt  24  is driven into the tube  54  and penetrates the frangible tube tip  56  prior to the bolt  24  finding the offset body fastener  50 . As an alternative, the tube  54  may be removed prior to insertion of the bolt  24 . The tube  54  is made of a thin material containing highly frangible serrations or notches that fracture readily upon application of: a small amount of upward force from the fastener, most commonly not exceeding 10 lbs f . 
     While certain representative embodiments and details have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in this art that various changes and modifications may be made therein without departing from the spirit or scope of the invention. It is, therefore, to be understood that changes can be made in the particular embodiments described which would be within the fully intended scope of the invention as defined by the following appended claims.