A MOTOR VEHICLE BUMPER MOUNTING ASSEMBLY

Abstract: A motor vehicle bumper is typically formed as an external shell extending across the front of the motor vehicle. The shell is attached to a motor vehicle bumper mounting assembly, and specifically to a cross beam formed as part thereof. The mounting assembly transfers an impact load away from an impact point to main load bearing members of the motor vehicle. If the height of the cross beam is not the same as that of the load bearing members in the motor vehicle body, twisting of the cross beam can occur. A motor vehicle bumper mounting assembly is disclosed having a straight tie bar (16) extending between first and second brackets (12, 14) and a curved armature (22). First and second ends (18, 20; 24, 26) of the tie bar (16) and the armature (22) are linked together. This structure resists the noted twisting forces induced on impact.

Description: A Motor Vehicle Bumper Mounting Assembly The present invention relates to an improved motor vehicle bumper mounting assembly. A motor vehicle bumper assembly is typically formed as an external shell extending across a front or rear end of the motor vehicle. The shell is attached to a motor vehicle body, and conveniently to a cross beam formed as part thereof. The cross beam itself is typically connected to longitudinal beams forming part of a chassis of the motor vehicle. The mounting assembly in this way transfers an impact load away from an impact point to main load bearing members of the motor vehicle. Problems arise due to the fact that the cross beam is typically curved across an end of the motor vehicle to suit the surface of the motor vehicle bumper. In most circumstances, the performance of this bumper mounting assembly is satisfactory. However, in certain situations a higher bumper performance is required. In particular if the height of the cross beam is not the same as that of the load bearing members in the motor vehicle body, twisting of the cross beam can occur. This can lead to further damage to the motor vehicle. A known bumper system having certain advantages is known from US 4 961 603. This bumper system includes a bumper member extending between the longitudinal load bearing beams. A tension means extends between the longitudinal beams to prevent the application of outwardly directed lateral forces to the longitudinal beams. The bumper member and the tensions means are directly and pivotally connected to one another through the longitudinal beams. According to a first aspect of the present invention a motor vehicle bumper assembly for a vehicle, said vehicle including first and second longitudinally extending load bearing members, is disclosed in which the bumper assembly comprises a straight tie bar having a first end and a second end, the tie bar extending between the first and second longitudinally extending members, and a curved armature having a first end and a second end, the respective first and second ends of the tie bar and the armature being Hnked together, characterised in that the tie bar and the curved armature are connected to the first and second longitudinally extending members by way of a bracket assembly. It is an advantage of the present invention that it resists the twisting forces induced on impact noted above, and also lateral forces that are generated as the curved cross beam is flattened during impact. Preferably, the tie bar is of generally "C" shaped configuration. Preferably, the bracket assembly comprises first and second brackets, each bracket comprising an upstanding portion, an outwardly directed first flange portion at one end thereof and a second flange extending substantially parallel to the first flange, the second flange extending from the upstanding portion, such that in use, the ends of the tie bar are located between the first and second flanges. Preferably, the ends of the armature are linked to the respective ends of the tie bar between the first and second flanges of the brackets. Preferably, the motor vehicle bumper mounting assembly further comprises at least one mounting strut extending between the tie bar and the armature. Preferably, the motor vehicle bumper mounting assembly further comprises a crush element between the tie bar and the armature. Alternatively, a crush element is included in the at least one mounting strut. The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a perspective view of a motor vehicle bumper mounting assembly in accordance with the present invention; Figure 2 illustrates in diagrammatic form the forces acting on a motor vehicle bumper mounting assembly; Figure 3 shows an end view in the direction of arrow A of the assembly of Figure 1; and Figure 4 shows a section along line IV- IV of Figure 1. Referring to the Figures 1, 3 and 4 there is shown a motor vehicle bumper mounting assembly 10 in accordance with the present invention. A motor vehicle bumper is typically formed as an external shell (not shown) extending across an end, for example a front, of a motor vehicle. A first bracket 12 and a second bracket 14 are shown laterally aligned. The brackets are adapted to be mounted on respective longitudinally extending load bearing beams, hereafter the longitudinals, of the motor vehicle chassis by any suitable means. A straight tie bar 16 having a first end 18 and a second end 20 extends between the first and second brackets. A curved armature 22 is provided having a first end 24 and a second end 26. The respective first and second ends of the tie bar and the armature are linked together. The respective ends may be linked directly to one another or by way of the first and second brackets. The tie bar 16 is of generally "C" shaped configuration. The se of the "C" section ensures that a box section 28 is generated at the first and second brackets. The box section resists the twisting forces induced in the tie bar caused by the tie bar being offset from the motor vehicle longitudinals. Each of the first and second brackets 12, 14 comprises an upstanding portion 30, an outwardly directed first flange 32 at one end thereof and a second flange 34 extending substantially parallel to the first flange. The second flange extends from the upstanding portion, such that in use, the ends of the tie bar fit between the first and second flanges. The ends of the armature 22 are linked to the respective ends of the tie bar 16 between the first and second flanges of the first and second brackets 12,14. In the embodiment illustrated the motor vehicle bumper mounting assembly further comprises a first mounting strut 36 and a second mounting strut 38. Each mounting strut extends between the tie bar 16 and the armature 22. The motor vehicle bumper mounting strut may further comprise a crush element (not shown) located within the strut, thereby further increasing energy absorption. Alternatively, or additionally, at least one crush element or at least one further crush element may be located between the tie bar 16 and the armature 22. The operation of the mounting assembly will now be described with reference also to Figure 2. Under impact (arrow A), the curved armature (line 40) is applying a load placing the armature in compression. The armature tries to straighten to the position shown in ghost (fine 42). The tie bar (line 44) however is then placed in tension resisting the movement of the armature. The applied loads are then directed towards the load bearing members of the motor vehicle (arrows B). This acts to strengthen the armature and reducing any deflection which may result. This allows a lighter structure to be used for the bumper than has been used previously, as well as an increased bumper performance in the space provided.

Claims: CLAIMS 1. A motor vehicle bumper mounting assembly for a vehicle, said vehicle including first and second longitudinally extending load bearing members, the bumper assembly comprising a straight tie bar having a first end and a second end, the tie bar extending between the first and second longitudinally extending members, and a curved armature having a first end and a second end, the respective first and second ends of the tie bar and the curved armature being linked together, characterised in that the tie bar and the curved armature are connected to the first and second longitudinally extending members by way of a bracket assembly. 2. A bumper mounting assembly according to claim 1, characterised in that the tie bar is of generally "C" shaped configuration. 3. A bumper mounting assembly according to claim 1 or claim 2, characterised in that the bracket assembly comprises first and second brackets, each bracket comprising an upstanding portion, an outwardly directed first flange portion at one end thereof and a second flange extending substantially parallel to the first flange, the second flange extending from the upstanding portion, such that in use, the ends of the tie bar are located between the first and second flanges. 4. A bumper mounting assembly according to claim 3, characterised in that the ends of the armature are hnked to the respective ends of the tie bar between the first and second flanges of the first and second brackets. 5. A bumper mounting assembly according to any previous claim, characterised in that the tie bar is offset from the first and second longitudinally extending members. 6. A bumper mounting assembly according to any previous claim, characterised in that the assembly further comprises at least one mounting strut extending between the tie bar and the armature. 7. A bumper mounting assembly according to claim 6, characterised in that a crush element is located within the at least one mounting strut. 8. A bumper assembly according to any previous claim, characterised in that the bumper assembly further comprises at least one crush element or at least one further crush element located between the tie bar and the armature.

Inventors: GREEN MARTIN CHRISTOPHER, GREEN, MARTIN, CHRISTOPHER
Applicants: GREEN MARTIN CHRISTOPHER, ROVER GROUP, GREEN, MARTIN, CHRISTOPHER, ROVER GROUP LIMITED
Application year: 1999
Main classification: B60R19
IPC codes: B60R19