Abstract:
An automobile bumper retention system is provided including a plastic foam energy absorbent bumper which is held firmly in place by a metal bumper beam. The beam is provided with integral ribs or beads that fit into a matching groove in the energy absorbing bumper in order to support the energy absorbing bumper in a snap-fit engagement or a slide-in engagement.

Description:
BACKGROUND OF TIE INVENTION 
     FIELD OF THE INVENTION 
     The present invention relates generally to an energy absorbent vehicle bumper, and more particularly to an automobile bumper retention system. 
     BACKGROUND OF THE INVENTION 
     The Federal Motor Vehicle Safety Standards (FMVSS) include specified requirements regarding front and rear bumper systems. These standards have been established so that all vehicles must meet the FMVSS in order to be certified as a saleable vehicle. The standards are set as the lowest specification level to be achieved for approval. in the case of bumpers, the FMVSS have greatly helped in reducing damage to vehicles from collisions occurring during parking maneuvers, traffic jams and in confined garages, etc. The vehicles are fitted with bumpers which are capable of absorbing the impact of a collision up to a certain speed without damaging to the vehicle. A conventional vehicle bumper incorporates a strong steel beam which extends across the vehicle and is secured to the supporting elements of the vehicle structure. An energy absorbing mechanism is secured to the steel beam and a continuous elastic casing conceals the steal beam and energy absorbing mechanism. Many designs have been implemented for securing the energy absorbing mechanism to the beam. Many of these designs have complex and expensive assembly systems for mounting the energy absorbing mechanism to the steel beam. Furthermore, manufacture of these bumper systems involves the use of complicated production equipment which increases the cost of the bumper. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to eliminate the mentioned disadvantages of prior art bumper systems and to provide an energy absorbing bumper retention system which is simple to assemble. 
     These and other objects of the present invention are obtained by providing an automobile bumper retention system including a rigid metal beam member and an energy absorbing bumper in snap-fit or slide-in engagement with the beam member. A bumper fascia is disposed over the energy absorbing bumper and is configured generally to a shape of the energy absorbing bumper such that the energy absorbing bumper provides inward support behind the bumper fascia. 
     The invention provides a simple locking mechanism including the beam cross member having an integral metal retaining rib or flange which protrudes into opposing molded-in grooves in the energy absorbing bumper in order to provide the snap-fit or slide-in engagement between the beam and the energy absorbing bumper. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood however that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more filly understood from the detailed description and the accompanying drawings, wherein: 
     FIG. 1 is an exploded perspective view of the automobile bumper retention system according to the principles of the present invention; 
     FIG. 2 is a perspective view of an automobile bumper retention system according to a second embodiment of the present invention; 
     FIG. 3 is a top view of the automobile bumper retention system shown in FIG. 2; 
     FIG. 4 is a cross-sectional view taken through the center of an automobile bumper retention system including a license plate assembly, according to the principles of the present invention; and 
     FIG. 5 is a cross-sectional view of the automobile bumper retention system according to the principles of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to FIGS. 1-5, the automobile bumper retention system  10  according to the principles of the present invention will now be described. Generally, the automobile bumper retention system  10  includes a support beam  12  which is fixed to the frame rails  14 , preferably by welding. An energy absorbent bumper  16  is supported by the beam  12  in a snap-fit or alternatively a slide-in engagement. 
     The beam  12  can be formed of rigid metal such as aluminum or steel. In the embodiments shown, the beam  12  is made from extruded aluminum having reinforcing ribs  18  for added strength while keeping the wall thickness relatively thin for reduction of weight. The beam  12  includes an upper flange portion  20  and a lower flange portion  22  each provided with an integrally formed projecting rib  24 . The projecting rib  24  disposed on the upper flange portion  20  extends downward toward the lower flange portion and the rib  24  on the lower flange portion  22  extends upward toward the upper flange portion  20 . 
     The energy absorbent bumper  16  is preferably formed from molded cellular plastic foam. The plastic foam can be selected from a variety of plastic foams such as urethane, polypropylene, and polystyrene. In addition, a solid plastic honeycomb configuration could also be used. The energy absorbent bumper  16  is provided with upper and lower retaining grooves  28 ,  30 , respectively. The energy absorbent bumper  16  is engaged with the beam  12  by sliding the upper surface  32  and lower surface  34  between the upper and lower flange portions  20 ,  22  of beam  12  and pressing the energy absorbent bumper  16  inward so that the integral projecting ribs  24  engage the upper and lower retaining grooves  28 ,  30 . Alternatively, the energy absorbent bumper  16  can be attached to the beam  12  by slide-in engagement, wherein the energy absorbent bumper  16  is slidably received by the beam  12  so that the projecting ribs  24  slidably engage the upper and lower grooves  28 ,  30 . 
     As best shown in FIGS. 4 and 5, a fascia panel  36  is provided in covering relationship over the energy absorbent bumper  16 . The energy absorbent bumper  16  is configured to provide inward support to the fascia  36  so that the curvature of the energy absorbent bumper  16  matches the inward curvature of the fascia  36 . Due to the added support of the energy absorbent bumper  16  behind the flexible bumper fascia  36 , the bumper fascia  36  can be made more flexible and therefore less susceptible to damage in low speed impacts. As shown in FIG. 5, the fascia is supported by mounting brackets  40 ,  42  which are mounted to the vehicle body ad frame structure. The fascia  36  is mounted by fasteners  44  as is well known in the art. 
     FIG. 4 shows a cross-sectional view through the center of a rear bumper having a license plate  46  mounted thereto. A lamp cut-out  48  is provided in the fascia  36  and a light assembly  50  is mounted within the lamp cut-out for illuminating the license plate  46 . 
     The bumper retention system of the present invention can be utilized with a straight bumper configuration as shown in FIG. 1, or with a curved bumper as shown in FIG.  2 . 
     The automobile bumper retention system of the present invention simplifies the assembly of the automotive energy absorption bumper system. The design of the present invention eliminates parts and reduces assembly labor. Vehicle quality will be greatly enhanced since many small retaining parts and hand assembly operations will be eliminated with the present invention. The invention applies to both the front and rear bumper systems. 
     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.