# Patent

## Title
Hybrid energy absorber for automobile bumper

## Abstract

An automobile bumper system including an isolator disposed adjacent a cross beam of an automobile frame, and a bumper edge guard strip mounted adjacent upper and/or lower edges of the cross beam. The bumper edge guard strip may include an upper extension fixedly engaged with an upper surface of the cross beam and a lower extension fixedly engaged with a frontal surface of the cross beam, with the upper extension having a length greater than the lower extension for distributing impact energy in a predetermined manner.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a Divisional of and claims benefit of priority on U.S. application Ser. No. 11/761,747 filed Jun. 12, 2007.


BACKGROUND OF INVENTION
a. Field of Invention
The invention relates generally to vehicle structural design, and more particularly, to the structural design of a vehicle bumper system for improved impact deformation and resistance, particularly during bumper over-ride and under-ride conditions.
b. Description of Related Art
As is known in the art, automobile bumper systems are designed to absorb and distribute impact energy in a predetermined manner. While bumpers systems are generally designed to meet at equal vertical impact levels, in the event of bumper over-ride or under-ride (i.e. in the event of a car/truck collision), even a low speed impact can result in excessive vehicle damage. This is because typical bumper systems may include energy absorbers disposed at a height-wise central area of the bumper for providing impact resistance against a bumper presumably disposed at the same height, leaving the upper and lower ends of a bumper susceptible to over-ride or under-ride type collision which could result in vehicle damage.
U.S. Pat. No. 6,609,740 to Evans is exemplary of known bumper system designs. While the Evans design aims to consistently distribute the load of an impact, this design is nevertheless optimally suited for impact resistance against a bumper presumably disposed at the same height.
For example, Evans, as illustrated in FIGS. 4-6 thereof, provides for a bumper structure including bumper energy absorber (22) having top and bottom box-shaped sections (27) and (27′), which extend outwardly from beam (21) and have rearwardly extending nose section (28) in between. As illustrated in FIG. 6, kick walls (30, 31) press into the top and bottom mid-walls (23, 24), resulting in a consistent and controlled collapse of the energy absorber and tubes of the bumper beam.
Thus, as discussed above, whereas Evans attempts to provide consistent load distribution, in the event of an over-ride or under-ride condition, the respective upper or lower area of the bumper would bear almost all of the impact load, thus inhibiting the intended bumper deformation as illustrated in FIG. 6 of Evans, and resulting in excessive bumper damage. Likewise, the Evans design limits energy absorbing capability within the height of the bumper beam, and not beyond.
It is therefore desirable to provide a bumper system which provides a cost-effective means for minimizing bumper damage in the event of an over-ride or under-ride impact condition, and likewise providing consistent and predetermined bumper deformation. It is also desirable to provide a bumper system which is simple to design and manufacture, and which is readily adaptable to a variety of vehicle designs.
SUMMARY OF THE INVENTION
The invention solves the problems and overcomes the drawbacks and deficiencies of prior art bumper designs by providing an automobile bumper system including an isolator disposed adjacent a cross beam of an automobile frame, and a bumper edge guard strip mounted adjacent upper and/or lower edges of the cross beam. The bumper edge guard strip may include an upper extension fixedly engaged with an upper surface of the cross beam and a lower extension fixedly engaged with a frontal surface of the cross beam, with the upper extension having a length greater than the lower extension for distributing impact energy in a predetermined manner.
For the automobile bumper system described above, the bumper edge guard strip may be fixedly mounted, such as by a bolt, screw and the like, with the upper and frontal surfaces of the cross beam. The bumper edge guard strip may include one or more ribs connected to the upper and lower extensions for adding rigidity to the edge guard strip. Further, the bumper edge guard strip may include one or more ribs protruding from the upper extension for limiting deformation of the bumper edge guard strip. The isolator may be disposed between bumper edge guard strips mounted between the upper and lower edges of the cross beam.
The invention also provides an automobile bumper system including an isolator disposed adjacent a cross beam of an automobile frame and made of a material of a first density, and one or more ribs made of a material of a second density, higher than the first density, provided substantially (or partially) within the isolator for distributing impact energy in a predetermined manner.
For the automobile bumper system described above, the rib may be disposed generally along an upper surface of the isolator, and one or more further ribs may be disposed along a lower surface of the isolator. The ribs provided along the upper and lower surfaces of the isolator may be mirror image ribs, and in a particular embodiment, the ribs provided along the upper and lower surfaces of the isolator may include a trapezoidal cross-section. Alternatively, the rib may extend generally horizontally and is disposed generally centrally along a height of the isolator, and one or more further ribs may extend generally vertically along the height of the isolator. The bumper system may further include a frontal surface formed of the second density for distributing impact energy in a predetermined manner. In the aforementioned embodiments, the material may be a foam material. Yet further, in another embodiment, the rib may include a plastic or metal covering.
The invention yet further provides an automobile bumper system including an isolator disposed adjacent a cross beam of an automobile frame and made of a material of a first density, and a frontal surface made of a material of a second density, higher than the first density, substantially covering a front area of the isolator. The bumper system may further include an intermediate layer disposed between the isolator and frontal surface, with the intermediate layer made of a material of a third density, higher than the first and second densities, for distributing impact energy in a predetermined manner.
For the automobile bumper system described above, the isolator and frontal surface may be made of a foam material, and the intermediate layer may be made of a foam, plastic or metal.
The invention also provides an automobile bumper system including an isolator disposed adjacent a cross beam of an automobile frame. A bumper edge guard strip may be mounted adjacent an upper or lower edge of the cross beam. The bumper edge guard strip may include an upper extension fixedly engaged with frontal or upper surfaces of the cross beam and a lower extension fixedly engaged with the frontal or upper surfaces of the cross beam. The upper and/or lower extensions may provide a deformation height less than, equal to, or greater than a height of the cross beam for distributing impact energy in a predetermined manner.
For the automobile bumper system described above, the bumper edge guard strip may be fixedly mounted, such as by a bolt, screw and the like, with the upper and frontal surfaces of the cross beam. The bumper edge guard strip may include one or more ribs connected to the upper and lower extensions for adding rigidity to the edge guard strip. Further, the bumper edge guard strip may include one or more ribs protruding from the upper extension for limiting deformation of the bumper edge guard strip. The isolator may be disposed between bumper edge guard strips mounted between the upper and lower edges of the cross beam.
The invention yet further provides an automobile bumper system including a cross beam mounted adjacent an automobile frame. A bumper edge guard strip may be mounted adjacent an edge of the cross beam. The bumper edge guard strip may include a first extension fixedly engaged with frontal or side surfaces of the cross beam and a second extension fixedly engaged with the frontal or side surfaces of the cross beam. The first and/or second extensions may provide a deformation height less than, equal to, or greater than a height of the cross beam for distributing impact energy in a predetermined manner.
For the automobile bumper system described above, the bumper edge guard strip may be fixedly mounted with the frontal or side surfaces of the cross beam. The bumper edge guard strip may include one or more ribs connected to the first and second extensions for adding rigidity to the edge guard strip. The bumper edge guard strip may include one or more ribs protruding from the first extension, with the rib limiting deformation of the bumper edge guard strip. An isolator may be disposed between bumper edge guard strips mounted between the edges of the cross beam.
Additional features, advantages, and embodiments of the invention may be set forth or apparent from consideration of the following detailed description, drawings, and claims. Moreover, it is to be understood that both the foregoing summary of the invention and the following detailed description are exemplary and intended to provide further explanation without limiting the scope of the invention as claimed.



BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate preferred embodiments of the invention and together with the detail description serve to explain the principles of the invention. In the drawings:
FIG. 1A is an isometric view of an embodiment of a bumper system according to the present invention, including a bumper edge guard strip for minimizing bumper deformation in the event of an over-ride condition;
FIG. 1B is an isometric view of another embodiment of the bumper system of FIG. 1A, including bumper edge guard strips mounted along the vertical edges of a cross beam;
FIG. 2 is a cross-sectional view of the bumper system of FIG. 1A, taken generally along line 2-2 in FIG. 1A, illustrating the bumper edge guard strip;
FIG. 3 is an exemplary cross-sectional view of the bumper system of FIG. 1A, taken generally along line 2-2 in FIG. 1A, but illustrating bumper edge guard strips for minimizing bumper deformation in the event of over-ride and under-ride conditions;
FIG. 4 is an exemplary cross-sectional view of the bumper system of FIG. 1A, similar to the view of FIG. 3, illustrating an exemplary over-ride impact condition and the associated bumper system deformation;
FIG. 5A is an isometric view of another embodiment of a bumper system according to the present invention, including strategically disposed variable density ribs and frontal surface;
FIG. 5B is a plan view of a cross beam used with the embodiment of FIG. 5A;
FIG. 6 is a cross-sectional view of the bumper system of FIG. 5A, taken generally along line 6-6 in FIG. 5A;
FIG. 7 is an exemplary cross-sectional view of the bumper system of FIG. 5A, illustrating an exemplary over-ride impact condition and the associated bumper system deformation (note absorber which can increase in height above the cross beam);
FIG. 8 is an isometric view of another embodiment of a bumper system according to the present invention, including strategically disposed variable density ribs;
FIG. 9 is a cross-sectional view of the bumper system of FIG. 8, taken generally along line 9-9 in FIG. 8;
FIG. 10 is an exemplary cross-sectional view of the bumper system of FIG. 8, illustrating an exemplary over-ride impact condition and the associated bumper system deformation (note absorber which can increase in height above the cross beam);
FIG. 11 is an isometric view of another embodiment of a bumper system according to the present invention, including strategically disposed metallic ribs;
FIG. 12 is a cross-sectional view of the bumper system of FIG. 11, taken generally along line 12-12 in FIG. 11;
FIG. 13 is an exemplary cross-sectional view of the bumper system of FIG. 11, illustrating an exemplary over-ride impact condition and the associated bumper system deformation (note absorber which can increase in height above the cross beam);
FIG. 14 is an isometric view of another embodiment of a bumper system according to the present invention, including a strategically disposed variable density frontal surface;
FIG. 15 is a cross-sectional view of the bumper system of FIG. 14, taken generally along line 15-15 in FIG. 14;
FIG. 16 is an exemplary cross-sectional view of the bumper system of FIG. 14, illustrating an exemplary over-ride impact condition and the associated bumper system deformation (note absorber which can increase in height above the cross beam);
FIG. 17 is an isometric view of another embodiment of a bumper system according to the present invention, including another embodiment of the bumper edge guard strip of FIG. 1;
FIG. 18 is a cross-sectional view of the bumper system of FIG. 17, taken generally along line 18-18 in FIG. 17; and
FIG. 19 is an exemplary cross-sectional view of the bumper system of FIG. 17, illustrating an exemplary over-ride impact condition and the associated bumper system deformation (note absorber which can increase in height above the cross beam).



DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings wherein like reference numerals designate corresponding parts throughout the several views, FIGS. 1A-19 illustrate various embodiments of a bumper system according to the present invention, with the first embodiment being generally designated “bumper system 10”.
Referring to FIGS. 1A-4, bumper system 10 may generally include a cross beam 12 mounted to frame structure 14 of an automobile (not shown). Cross beam 12 may include an isolator 16 made of foam or other materials known in the art, with isolator 16 being attached to beam 12 in a known manner. A bumper edge guard strip 18 (made of metal for example) may be fixedly mounted or otherwise fixedly engaged (i.e. in a recess (not shown)) along upper and/or lower edges 20, 22 of cross beam 12. Strip 18 may include an upper extension 24 fixedly mounted to or otherwise engaged with upper surface 26 of cross beam 12 by bolt 28, and further include a lower extension 30 fixedly mounted to or otherwise engaged with frontal surface 32 of the cross beam by bolt 34. As readily evident to those skilled in the art, other means, such as riveting etc., may be used for attachment of extensions 24, 30 to cross beam 12. A plurality of ribs 36 may be provided in engagement with, or otherwise formed with upper and lower extensions 24, 30 for adding rigidity to the structure of strip 18.
During an over-ride type impact as illustrated in FIG. 4, the front surface 38 of bumper edge guard strip 18 may thus contact impacting bumper 40 as illustrated, with upper extension 24 deforming in direction A, to minimize bumper deformation. Thus compared to an over-ride type impact without the provision of bumper edge guard strip 18, impact bumper 40 would contact the upper area of isolator 16 and may cause dive-down type movement (or lifting movement in the event of an under-ride type impact) of the vehicle (not shown). With the provision of bumper edge guard strip 18, strip 18 may absorb the impact energy and deform accordingly to prevent such a dive-down (or lifting) movement of the vehicle caused by an over-ride (or under-ride) impact condition.
Referring next to FIGS. 5A-7, another embodiment of the bumper system, hereinafter designated bumper system 50, will be described in detail.
Compared to bumper system 10 of FIGS. 1A-4, bumper system 50 may generally include an isolator 52 formed of a predetermined foam density (i.e. approximately 50-80 g/L), and horizontal and vertical ribs 54, 56 formed of a higher density foam (i.e. greater than approximately 100 g/L). Isolator 52 may further include a frontal surface 58 likewise formed of a higher density foam (i.e. greater than approximately 100 g/L). Yet further, compared to cross beam 12 of the FIGS. 1A-4 embodiment, cross beam 60 of the FIGS. 5A-7 embodiment may include a curved profile, and mirror image protrusions 62, 64 engaged with frame structure 14.
During an over-ride type impact as illustrated in FIG. 7, the upper surface of frontal surface 58 may thus contact impacting bumper 40 as illustrated, with the upper area of isolator 52 deforming in direction A, to minimize bumper deformation. As discussed above for bumper system 10, compared to an over-ride type impact without the provision of frontal surface 58 (and ribs 54, 56), impact bumper 40 would contact the upper area of isolator 52 and may cause dive-down type movement (or lifting movement in the event of an under-ride type impact) of the vehicle (not shown). With the provision of frontal surface 58 (and ribs 54, 56), these components may absorb the impact energy and deform accordingly to prevent such a dive-down (or lifting) movement of the vehicle caused by an over-ride (or under-ride) impact condition.
Referring next to FIGS. 8-10, another embodiment of the bumper system, hereinafter designated bumper system 80, will be described in detail.
Compared to bumper system 10 of FIGS. 1A-4, bumper system 80 may generally include an isolator 82 formed of a predetermined foam density (i.e. approximately 50-80 g/L), and mirror image horizontal ribs 84, 86 formed of a higher density foam (i.e. greater than approximately 100 g/L). In the particular embodiment illustrated, ribs 84, 86 may include a trapezoidal configuration, and be substantially or partially embedded in isolator 82. As discussed for the embodiment of FIGS. 5A-7, compared to cross beam 12 of FIGS. 1A-4, cross beam 88 of the FIGS. 8-10 embodiment may include a curved profile, and mirror image protrusions 90, 92 engaged with frame structure 14.
During an over-ride type impact as illustrated in FIG. 10, the upper surface of isolator 82 and thereafter rib 84 may thus contact impacting bumper 40 as illustrated, with the upper area of rib 84 deforming in direction A, to minimize bumper deformation. As discussed above for bumper system 10, compared to an over-ride type impact without the provision of rib 84 (and rib 86), impact bumper 40 would contact the upper area of isolator 82 and may cause dive-down type movement (or lifting movement in the event of an under-ride type impact) of the vehicle (not shown). With the provision of rib 84 (and rib 86), these components may absorb the impact energy and deform accordingly to prevent such a dive-down (or lifting) movement of the vehicle caused by an over-ride (or under-ride) impact condition.
Referring next to FIGS. 11-13, another embodiment of the bumper system, hereinafter designated bumper system 100, will be described in detail.
Compared to bumper system 10 of FIGS. 1A-4, bumper system 100 may generally include an isolator 102 formed of a predetermined foam density (i.e. approximately 50-80 g/L), and mirror image horizontal ribs 104, 106 formed of a higher density foam (i.e. greater than approximately 100 g/L) and substantially or partially embedded in isolator 102. Isolator 102 may further include mirror image metallic strips 108, 110 embedded within isolator 102 and disposed around ribs 104, 106. As discussed for the embodiment of FIGS. 5A-7, compared to cross beam 12 of FIGS. 1A-4, cross beam 112 of the FIGS. 11-13 embodiment may include a curved profile, and mirror image protrusions 114, 116 engaged with frame structure 14.
During an over-ride type impact as illustrated in FIG. 13, the upper surface of isolator 102 and thereafter rib 104 having metallic strip 108 may thus contact impacting bumper 40 as illustrated, with the upper area of rib 104 deforming in direction A, to minimize bumper deformation. As discussed above for bumper system 10, compared to an over-ride type impact without the provision of rib 104 including metallic strip 108 (and rib 106 including metallic strip 110), impact bumper 40 would contact the upper area of isolator 102 and may cause dive-down type movement (or lifting movement in the event of an under-ride type impact) of the vehicle (not shown). With the provision of rib 104 including metallic strip 108 (and rib 106 including metallic strip 110), these components may absorb the impact energy and deform accordingly to prevent such a dive-down (or lifting) movement of the vehicle caused by an over-ride (or under-ride) impact condition.
Referring next to FIGS. 14-16, another embodiment of the bumper system, hereinafter designated bumper system 120, will be described in detail.
Compared to bumper system 10 of FIGS. 1A-4, bumper system 120 may generally include an isolator 122 formed of a predetermined foam density (i.e. approximately 50-80 g/L) and a frontal surface 124 formed of a higher density foam (i.e. greater than approximately 100 g/L). Isolator 122 may further include a layer 126 embedded between layers 122, 124, with layer 126 being made of a higher density foam, plastic or metal. As discussed for the embodiment of FIGS. 5A-7, compared to cross beam 12 of FIGS. 1A-4, cross beam 128 of the FIGS. 14-16 embodiment may include a curved profile, and mirror image protrusions 130, 132 engaged with frame structure 14.
During an over-ride type impact as illustrated in FIG. 16, the upper surface of frontal surface 124 may thus contact impacting bumper 40 as illustrated, with the upper area of isolator 122 deforming in direction A, to minimize bumper deformation. As discussed above for bumper system 10, compared to an over-ride type impact without the provision of front surface 124 (and layer 126), impact bumper 40 would contact the upper area of isolator 122 and may cause dive-down type movement (or lifting movement in the event of an under-ride type impact) of the vehicle (not shown). With the provision of frontal surface 124 (and layer 126), these components may absorb the impact energy and deform accordingly to prevent such a dive-down (or lifting) movement of the vehicle caused by an over-ride (or under-ride) impact condition.
Referring next to FIGS. 17-19, another embodiment of the bumper system, hereinafter designated bumper system 140, will be described in detail.
Compared to bumper system 10 of FIGS. 1A-4, bumper system 140 may generally include an isolator 142 having bumper edge guard strip 146 including ribs 148 for limiting deformation of strip 146 by contacting cross beam 150.
During an over-ride type impact as illustrated in FIG. 19, the front surface of bumper edge guard strip 146 may thus contact impacting bumper 40 as illustrated, with upper extension 24 deforming in direction A, to minimize bumper deformation. Thus compared to an over-ride type impact without the provision of bumper edge guard strip 146, impact bumper 40 would contact the upper area of isolator 142 and may cause dive-down type movement (or lifting movement in the event of an under-ride type impact) of the vehicle (not shown). With the provision of bumper edge guard strip 146 including ribs 148, strip 146 may absorb the impact energy and deform accordingly to prevent such a dive-down (or lifting) movement of the vehicle caused by an over-ride (or under-ride) impact condition.
To thus summarize, the present invention provides a bumper system which provides a cost-effective means for minimizing bumper damage in the event of an over-ride or under-ride impact condition with the provision of the afore-described bumper edge guard strips 18, 146, ribs 54, 56, 84 and 86, and frontal surfaces 58, 124. As also described above, the provision of the noted elements provides consistent and predetermined bumper deformation, with the design being readily adaptable to a variety of vehicle designs.
Those skilled in the art would readily appreciate in view of this disclosure that various modifications could be made to the aforementioned components, without departing from the scope of the present invention. For example, whereas the embodiments of FIGS. 1A-19 have been described as separately including components such as bumper edge guard strips 18, 146, ribs 54, 56, 84 and 86, and frontal surfaces 58, 124, it should be noted that these components may be used in combination (i.e. bumper edge guard strips 18 of the FIGS. 1A-4 embodiment may be used in conjunction with the embodiment of FIGS. 14-16 etc.). For the embodiment of FIGS. 1A-4, bumper edge guard strips 18 (and 146) may be used without isolator 16. The aforementioned bumper edge guard strips 18, 146, ribs 54, 56, 84 and 86, and frontal surfaces 58, 124 may be used for localized conditions on a cross beam (as opposed to along the entire length of a cross beam) as needed. Yet further, the aforementioned bumper edge guard strips 18, 146, and ribs 54, 56, 84 and 86 may be disposed in a 90° (or in an oblique) configuration for predetermined deformation of the vertical (see FIG. 1B; or oblique) edges or other areas of a bumper structure.
Although particular embodiments of the invention have been described in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those particular embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.

## Claims

1. An automobile bumper system comprising:
an isolator disposed adjacent a cross beam of an automobile frame and made of a material of a first density;
a frontal surface made of a material of a second density, higher than said first density, substantially covering a front area of said isolator; and

an intermediate layer made of foam and disposed between said isolator and frontal surface, said intermediate layer made of a material of a third density, higher than said first and second densities, for distributing impact energy in a predetermined manner.

2. An automobile bumper system according to claim 1, wherein said isolator and frontal surface are made of a foam material.

3. The automobile bumper system of claim 1 wherein the frontal surface limited to extending between a top surface of the isolator to a bottom surface of the isolator.

4. The automobile bumper system of claim 1 wherein the isolator deforms upward when impacted on an upper portion of the front face of the isolator.

5. The automobile bumper system of claim 1 wherein the isolator deforms downward when impacted on a lower portion of the front face of the isolator.

6. An automobile bumper system comprising:
an isolator disposed adjacent a cross beam of an automobile frame and comprising a first foam material;
a frontal surface comprising a second foam material substantially covering a front area of the isolator, wherein a top surface of the isolator remains uncovered by said frontal surface and a bottom surface of the isolator remains uncovered by said frontal surface; and
an intermediate layer comprised of a third foam material and disposed between the isolator and the frontal surface, the intermediate layer being substantially thinner than the isolator wherein the third foam material has a higher density than the first foam material and a higher density than the second foam material.

7. The automobile bumper system of claim 6 wherein said second foam material has a higher density than said first foam material.

8. The automobile bumper system of claim 6 wherein the first foam material has a density in the range of 50-80 g/L and the second foam material has a density greater than 100 g/L.

9. The automobile bumper system of claim 6 wherein the isolator deforms upward when impacted on an upper portion of the front face of the isolator.

10. The automobile bumper system of claim 6 wherein the isolator deforms downward when impacted on a lower portion of the front face of the isolator.

11. An automobile bumper system comprising:
a cross beam;
an isolator comprising a first foam material substantially covering an entire front surface of the cross beam;
a frontal surface comprising a second foam material covering a front area of the isolator, the frontal surface limited to extending between a top surface of the isolator to a bottom surface of the isolator wherein the second foam material has a higher density than the first foam material; and
an intermediate layer comprising a third foam material disposed between the isolator and the frontal surface.

12. The system of claim 11 wherein the isolator has a substantially rectangular cross section.

13. The system of claim 11 wherein the intermediate layer is thinner than the isolator and thinner than the frontal surface.

14. The system of claim 11 wherein the isolator deforms upwards when impacted frontally near an upper area of the isolator.

15. The system of claim 11 wherein the isolator deforms downwards when impacted frontally near a lower area of the isolator.

16. The system of claim 11 wherein the front surface of the cross beam is substantially flat.