Vehicle fenders – Buffer or bumper type – Bumper having impact force absorbing means directly...
Reexamination Certificate
1999-04-15
2001-11-13
Pape, Joseph D. (Department: 3612)
Vehicle fenders
Buffer or bumper type
Bumper having impact force absorbing means directly...
C293S133000, C293S120000
Reexamination Certificate
active
06315339
ABSTRACT:
The present invention relates to a shock absorber of undulating section and to a bumper provided with such a shock absorber.
BACKGROUND OF THE INVENTION
Motor vehicle bumpers have an outer skin which serves firstly to provide an esthetic function of extending the bottom of the front or back portion of the bodywork of the vehicle, and secondly a mechanical function of constituting an impact surface for receiving impacts to which the vehicle may be subject.
Behind the bumper skin, there is provided a shock absorber whose function is to take up the forces transmitted by the skin and to absorb the major fraction of the energy thereof before transferring it to the side rails of the vehicle.
In general, the shock absorbers are situated in line with the side rails and they are interconnected by a cross-member which transfers to them the forces to which the bumper is subject. The shock absorbers are made to measure and are quite expensive, such that in certain down-market vehicles, they are replaced by a low energy shock absorbing system of the polypropylene foam type whose sole purpose is to limit damage to the skin of the bumper in the event of small bumps.
SUMMARY OF THE PRESENT INVENTION
The present invention seeks to provide a high energy shock absorber which is not only cheaper but is also very easy to adapt to different vehicles.
The present invention provides a shock absorber for a motor vehicle, to be interposed in a bumper between a cross-member interconnecting the two side rails of the vehicle and a bumper shield, the shock absorber being characterized by the fact that it is constituted by a sheet of undulating section.
The shock absorber of the invention draws advantage from the fact that it is positioned between the cross-member and the shield, thereby giving it a large working area and correspondingly reducing the pressure to which it is subjected during a shock.
Thus, because it is of undulating section, a sheet of plastics material or of other material suffices to provide a shock absorber that is effective.
In addition, it will be understood that using a sheet of undulating section makes a degree of modularity possible, since the sheet can be cut to the desired dimensions without the entire architecture of the shock absorber needing to be redefined.
The undulating section of the shock absorber of the invention presents the advantage of being easy to mold and unmold in a mold having two parts, one of which can be moved in translation along an axis.
In addition, the rounded shapes projecting from the face(s) of the shock absorber reduce or even eliminate the phenomenon of whitening that occurs in the event of an impact on a visible part that is in contact with an absorber and when the absorber has rigid edges as is the case, for example, of a honeycomb structure.
In a first embodiment of the invention, the shock absorber includes egg-shapes in relief.
In a second embodiment, the shock absorber is corrugated in shape, which is easier to inject than the preceding embodiment because the injection flows in this case are subjected only to very little disturbance.
If the shock absorber of the invention is constituted solely by shapes of undulating section, it is possible to use a mold that is simple without inserts or other complex moving parts.
In addition, in order to obtain an undulating section, there is no need for the mold to have a surface state that is of quality as good as that required for unmolding shapes having surfaces that are parallel to the opening direction of the mold, as is the case, for example, with honeycomb reinforcement.
The shock absorber of the invention can be made by any method for transforming plastics material, i.e. not only by molding, but also by thermoforming, for example, or indeed by extrusion if a corrugated shock absorber is to be made.
In a particular embodiment of the invention, small blocks of foam fill the recesses that result from the presence of the undulating shapes, so as to increase the energy-absorbing performance of the shock absorber.
For the same purpose, ribs can be provided in the bottoms of the corrugations or egg-shapes of the shock absorber.
Such ribs can also be taken advantage of to protect headlight-washer equipment as is conventionally received in a location at the front of the vehicle that is highly exposed to impacts. To this end, the array of ribs can be made locally more dense so as to shelter the equipment.
In an embodiment of the invention, the shock absorber possesses symmetry, planar relative to its midplane, or central relative to a point of its midplane, so that it can be put into position equally well in either direction, thus facilitating installation.
The present invention also provides a bumper provided with a shock absorber as described above.
In a particular embodiment, the shock absorber is integrated in the bumper e.g. being integrally molded with the skin of the bumper which, in cross-section has a setback forming the said shock absorber.
In which case, the bumper may optionally include a cover closing the opening which appears in the skin because of the presence of the integrated shock absorber.
In a particular embodiment, in which the shock absorber has egg-shapes in relief, the shock absorber is placed in the bumper in such a manner that the concave sides of the egg-shapes face towards the front of the vehicle.
In another embodiment that is compatible with the preceding embodiments, the bumper includes corners at its side ends and the axes of the corrugated shapes or egg-shapes of the shock absorber situated in the vicinity of said corners face in the direction from which impacts are statistically most likely, i.e. a direction substantially perpendicular to the surface of the skin of the bumper overlying each corrugated shape or egg-shape.
The shock absorber of the invention is suitable for use not only in bumpers, as already explained, but also in any vehicle bodywork part such as a door panel or a fender, in particular because it is very flexible and can be installed between two parts following the curvature thereof and without requiring special preparation.
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Berger Guillaume
Devilliers Olivier
Roussel Thierry
Compagnie & Plastic Omnium
Oliff & Berridg,e PLC
Pape Joseph D.
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