Vehicle fenders – Buffer or bumper type – Composite bumper
Reexamination Certificate
2002-02-01
2003-08-26
Dayoan, D. Glenn (Department: 3612)
Vehicle fenders
Buffer or bumper type
Composite bumper
C293S120000
Reexamination Certificate
active
06609740
ABSTRACT:
BACKGROUND OF THE PRESENT INVENTION
The present invention relates to automotive bumper systems having beams and energy absorbers located on faces of the beams.
Many vehicle designs use energy absorbers positioned on a face or front surface of a steel bumper beam to improve energy absorption of a bumper system. The energy absorbers provide an initial level of energy absorption for low impact, including reducing damage during low impact, and also provide a supplemental level of energy absorption during high impact (i.e. before and at the time that the beam and vehicle begin to absorb substantial amounts of energy). Usually, the energy absorbers are fastened to the bumper beam with fasteners that assure accurate positioning of the energy absorber on the beam. The reasoning includes accurately positioning the energy absorber on the bumper beam to assure consistent performance, as well as to assure accurate positioning for aesthetics and assembly (e.g. to assure a good fit of the front-end fascia over the energy absorber and beam during assembly).
However, improvements are desired in terms of temporary and permanent attachment, and for improved and more reliable energy absorption. Typically, attachment of the energy absorber to bumper beams requires a plurality of mechanical fasteners. This is disadvantageous since mechanical fasteners require manual labor to install, which can add undesirably to cost. Also, the mechanical fasteners can result in localized and non-uniform stress distribution during impact, resulting in inconsistent collapse of the bumper system and poor energy absorption on impact. Further, fixing the energy absorber to the beams results in an inability of the energy absorber to shift and adjust to non-perpendicular and uneven loads transmitted from the impacting bodies. At the same time, depending on the bumper system, sometimes shifting of an energy absorber is not good since it can result in unpredictable, premature and non-uniform collapse, resulting in poor or inconsistent energy absorption by the bumper system.
Improvement is also desired for corner impact structure on bumper systems. Many existing bumper systems require that a front surface of an end of a bumper beam be shaped at an increased angle relative to the front of rest of the bumper beam to match an aerodynamic curvature of the vehicle at its front fender. One way to achieve this is by miter cutting an end of the bumper beam at an angle, and thereafter welding a plate onto the angled end to form a compound-angled flat front surface for supporting an energy absorber such as a foam cushion. Another way is to deform or crush an end of the bumper beam to form an angled front surface. Yet another way is to weld a bracket onto an end of the bumper beam, with the bracket extending longitudinally beyond the bumper beam to form the desired shape. However, all of these alternatives have drawbacks. For example, they each require a secondary operation, result in increased dimensional variation, and require significant investment in capital equipment. Further, they can lead to increased scrap, a substantial increase in manpower and manufacturing time, and substantial increase in inventories and work in process.
For all of the above reasons, there is a desire for bumper systems that yield a better, more consistent, more reliable, and greater impact energy absorption, both for low and high impact events, and also for square and skewed impact directions. Also, there is a desire for improvements facilitating assembly of an energy absorber to a beam, with lower cost and fewer parts, and with less labor. Still further, there is a desire for energy absorber designs that allows adjustment and tuning for optimal front end and corner impact strengths, even late in the bumper development program, and yet that do not require expensive or complex molding techniques or assembly techniques nor secondary miter cutting or crush forming bumper end sections. Still further, there is a desire for energy absorber designs that are adaptable for use with many different bumper beam cross-sectional shapes and sizes. Also, energy absorber designs are desired that are flexible and usable on non-linear bumper beams having different curvatures and longitudinal sweeps, and having different cross sections.
SUMMARY OF THE PRESENT INVENTION
In one aspect of the present invention, a bumper system for vehicles includes a bumper beam and an energy absorber. The bumper beam has a continuous tubular cross section with top and bottom front walls defining a front surface that extends vertically when the bumper beam is in a car-mounted position and with top and bottom mid-walls defining a longitudinally-extending channel in the front surface between the top and bottom front walls. The energy absorber includes box-shaped sections that abut the front surface of the bumper beam and further includes rearwardly-extending nose sections that extend into the channel. In one form, the nose sections include collapse-controlling kick walls that lie along and abut the top and bottom mid-walls and that are connected to the box-shaped sections so that, upon impact by an object against the bumper system, the kick walls press into the top and bottom mid-walls with increasing force as the object strikes the box-shaped sections with increasing force. This structure results in a controlled flexure and collapse of the box-shaped sections of the polymeric energy absorber and of the top and bottom mid-walls of the bumper beam as a system.
In another aspect of the present invention, a bumper system for vehicles includes a bumper beam and an energy absorber. The bumper beam has a continuous tubular cross section with a front surface that extends vertically when the bumper beam is in a car-mounted position. The bumper beam has mid-walls extending to the front surface that form a longitudinally-extending channel across a middle area of the front surface. The energy absorber includes a rear surface abutting the front surface of the bumper beam. The energy absorber has first, second, third, and fourth parallel walls that extend horizontally, the first parallel wall being at a top location and the fourth parallel wall being at a bottom location. The energy absorber further includes top walls interconnecting the first and second parallel walls to form a top box section, and includes bottom walls interconnecting the third and fourth parallel walls to form a bottom box section. The energy absorber further has a nose section that extends rearwardly of the top and bottom walls into the bumper beam. The nose section includes kick walls that, upon impact against the bumper system, press laterally against the mid-walls of the bumper beam, causing the mid-walls and hence the bumper beam to collapse in a more controlled manner. By this arrangement, the collapse load of the beam is locally controlled for improved consistent collapse and energy absorption.
In another aspect of the present invention, a bumper system for vehicles includes a B-shaped bumper beam with a face and a longitudinally-extending channel in the face, and an energy absorber having energy-absorbing sections engaging the face. The energy absorber further includes at least one nose section connected to the energy-absorbing sections and that extends into the channel.
In still another aspect of the present invention, a bumper system for vehicles includes a bumper beam with a face and a channel in the face, and an energy absorber having first energy-absorbing sections engaging the face. The energy absorber further includes second energy-absorbing sections aligned with the channel, the second energy-absorbing sections being spaced from a bottom of the channel and being configured to move into contact with the bottom of the channel during an initial phase of an impact against the bumper system and further being configured to absorb energy during a later phase of the impact.
In yet another aspect of the present invention, a bumper system for vehicles includes a tubular bumper beam including a front face and open ends, and an energ
Carpenter Scott
Dayoan D. Glenn
Price Heneveld Cooper DeWitt & Litton
Shape Corporation
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