GB2341148A

GB2341148A - A vehicle bumper arrangement

Info

Publication number: GB2341148A
Application number: GB9913271A
Authority: GB
Inventors: Darryl Moore
Original assignee: MG Rover Group Ltd
Current assignee: MG Rover Group Ltd
Priority date: 1998-06-26
Filing date: 1999-06-09
Publication date: 2000-03-08
Also published as: GB9913271D0; GB9813711D0

Abstract

A vehicle bumper arrangement is provided to facilitate bumper compatibility between a large off-road vehicle and a normal road vehicle. The arrangement can comprise a single impact element 3 arranged to be displaceable between a normal configuration N and a retracted or raised configuration R. In the normal configuration N, an impact front is provided for good bumper compatibility with normal height road vehicles , whilst in the retracted or raised configuration R, the vehicle 1 is provided with an adequate approach angle A-A suitable for off-road activities. The arrangement may alternatively comprise a first impact element (23, Fig 2) and a second impact element (24) which are relatively displaceable. Displacement between the normal configuration and the retracted configuration is achieved axially or by rotation about a pivot between the first and second impact elements (23,24).

Description

2341148 A VEHICLE BUMPER ARRANGEMEN The present invention relates to a

bumper arrangement and more particularly to a bumper arrangement for a large, so-called off-road, motor vehicle.

There is an increasing tendency for motor vehicles ostensibly designed for off-road use to be predominantly operated upon normal highways. Unfortunately, there is a problem when such large off-road vehicles collide with a smaller vehicle due to the inherent height differential between their respective vehicle bumper arrangements. This can be detrimental in that the bumper arrangement is also configured as a main load path to the primary energy absorption mechanism, ie. crush cans of a vehicle. Furthermore, normally a bumper arrangement will itself be deformable in order to absorb a proportion of vehicle collision energy.

When a large off-road vehicle collides with a lower height normal road vehicle, whether it be at the front or rear, that off-road vehicle's bumper arrangement will not contact the lower vehicle's bumper arrangement in order to achieve the desired and predicted energy absorption for safety purposes. In such circumstances, the energy absorption mechanisms of both vehicles, ie. large off-road vehicle and lower normal vehicle, do not cooperate as intended.

With regard to side impact between a large off-road vehicle and a lower normal road vehicle there will be non-compatibility between the absorption mechanisms of the respective two vehicles. Typically, a sill area of the lower normal road vehicle would be arranged to act as the main collision energy absorption mechanism during a side collision. However, the off-road vehicle's bumper arrangement would not contact that lower vehicle's doors at an appropriate height to achieve predicted energy absorption. The off-road vehicle's bumper arrangement would contact higher up than expected upon the lower road vehicle's door, door jamb and B post.

Essentially, the problem is one of non-compatibility between bumper arrangements of the large off-road vehicle and the lower height normal road vehicle.

Vehicle bumper compatibility is a consistent problem exercising legislators and motor vehicle manufacturers in order to provide the desired levels of safety.

It is an objective of the present invention to provide a vehicle bumper arrangement which facilitates better compatibility with other vehicles without significantly diminishing the off-road capabilities of a motor vehicle designed for such activity.

In accordance with a first embodiment of the present invention there is provided a motor vehicle bumper arrangement comprising an impact element secured to displacement means to provide an aesthetically consistent profile for a vehicle to which the bumper arrangement is attached, said impact element being relatively displaceable by said displacement means between a normal configuration for road use and a raised or retracted configuration more suitable for off-road vehicle use, said normal configuration presenting said impact element for compatibility with other road vehicles of a lower bumper height, whilst said raised configuration substantially presents said impact element to improve approach angle of a vehicle to which the vehicle bumper arrangement is attached in comparison with the normal configuration.

In accordance with a second embodiment of the present invention there is provided a motor vehicle arrangement comprising a first impact element and a second impact element secured to displacement means to provide an aesthetically consistent profile for a vehicle to which the bumper arrangement is attached, said first and said second impact elements being relatively displaceable by said displacement means between a normal configuration for road use and a retracted configuration more suitable for off-road vehicle use, said normal configuration presenting both said first and said second impact elements for compatibility with other road vehicles of a lower bumper height whilst said retracted configuration presents substantially only said first impact element for impact and with said second impact element relatively displaced with regard to said first impact element to improve approach angle of a vehicle to which the vehicle bumper arrangement is attached in comparison with the normal configuration.

Preferably, the displacement means is axial.

Typically, a grille element will fill any space between said first and said second impact element when in the normal configuration.

The displacement means may be operated manually or mechanically.

I The first and/or the second impact element is normally coupled to the vehicle collision energy absorption mechanism such as crush cans, etc.

The first and/or second impact element may be a unitary cross-beam lateral to a vehicle upon which the arrangement is attached or segmented to allow differentiated but controlled deformation under collision impact.

The first and/or the second impact element may be deformable to act as an impact energy absorption mechanism in its own right.

Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which:

Figure I is a schematic side elevation of a first embodiment of the present bumper arrangement; and Figure 2 is a schematic side elevation of a second embodiment of the present bumper arrangement.

With a large off-road vehicle, in order to achieve bumper arrangement compatibility with other road vehicles, a balance must be struck between impact height and off-road capability in terms of approach angle to avoid bumper grounding when the vehicle traverses rough terrain.

In accordance with a first embodiment of the present invention depicted in figure 1, a variable geometry bumper arrangement is provided comprising a separate impact element and a front facia of the vehicle appropriately displaceable relative to each other in order to achieve a broader impact range for vehicle to vehicle bumper compatibility whilst retaining off-road approach angle for adequate rough terrain operation.

Displacement of the impact element can be achieved by axial or rotary displacement therebetween. However, axial displacement is preferred in order to allow easier coupling to existing energy absorption mechanisms within a vehicle such as crush cans, etc.

In Figure 1, a motor vehicle 1 includes a bumper arrangement 2 about the front periphery of that vehicle 1. The bumper arrangement 2 comprises an impact element 3 and a vehicle grille facia 4. The impact element 3 takes the form of a bulbous beam typical of a motor vehicle bumper, whilst the facia 4 takes the form of a grille and spoiler behind the - impact element 3. The impact element 3 is coupled to energy absorption mechanisms 5 in a conventional manner. Thus, the impact element 3 is coupled through a bumper armature 6 to an energy absorption mechanism 5 in the form of a crush can. Those skilled in the art will appreciate that a crush can is deformed during a collision to absorb collision impact energy.

In the embodiment depicted in Figure 1, relative displacement between the impact element 3 and the facia 4 is all achieved through displacement of the impact element 3 in the direction of the arrow heads between a normal configuration N and a raised configuration R. Displacement is substantially axial and vertical.

In the normal configuration N (impact element 3 in broken line), it will be appreciated that the impact element 3 is at a lower level, and so at reduced height, such that the bumper arrangement 2 is more compatible with other normal height road vehicles. In this normal configuration N, a lower impact front is presented comprising a front surface 7n of the impact element 3. In such circumstances, bumper compatibility between a large off-road vehicle 1 with other lower normal road vehicles is more acceptable and, more importantly collision impact energy will be transferred to respective energy absorption mechanisms 5 within vehicles in collision rather than precipitating other less favourable collision coupling.

In the raised configuration R, the impact element 3 (solid line) is at an elevated position or height in order to ensure an acceptable approach angle A-A is retained for the vehicle 1 suitable for off-road operation. The facia 4 is arranged to give a recessed or reclining slope surface 9 away from the front of the vehicle 1 in order to retain this approach angle A-A.

Displacement between the raised configuration R and the normal configuration N can be achieved by a multitude of conventional mechanical and manual techniques. For example, the impact element 3 could be retained within a latched slot mechanism with the element 3 retained by appropriate latches at the raised configuration R or the normal configuration N. Alternatively, a ratchet or screw thread displacement between the raised configuration R and the normal configuration N could be used appropriately powered by a motor as required.

It will be appreciated in the embodiment depicted in Figure 1 that the facia 4 comprising a spoiler and grille to define the surfaces 8, 9 is substantially static whilst the impact element 3 is axially displaceable in a vertical direction (arrow heads) to define the normal configuration N and raised configuration R. Thus, the facia 4 through the spoiler and grille provides a consistent aesthetic profile for the vehicle 1 whilst the first impact element 3 achieves the desired differentiation between onroad vehicle bumper height compatibility and off-road approach angles A-A acceptability.

As indicated above, it is important that the bumper arrangement 2 is appropriately coupled with the energy absorption mechanism 5 of the vehicle 1. This energy absorption mechanism 5, typically in the form of crush cans, is coupled directly to the vehicle 1 through its chassis 10. Those skilled in the art will appreciate that with a vertical and axial displacement between the raised configuration R and the normal configuration N that coupling to this energy absorption mechanism 5 may be difficult. For example, as illustrated in Figure 1, the energy absorption mechanism 5 in the form of a crush can coupled to the bumper armature 6 is integrally displaced with the impact element 3 which itself is secured within an adjunct element 11 of the chassis 10.

In Figure 2, an alternative second bumper arrangement in accordance with the present 1 invention is depicted. In this second bumper arrangement, a vehicle 21 has a bumper arrangement comprising a first bumper element 23 and a second bumper element 24.

In the embodiment depicted in Figure 2, the first impact element 23 is substantially fixed and consistent with the grille 28 within the vehicle 21 aesthetic profile. Thus, the element 23 is appropriately coupled to a crush can element 25 through a bumper armature 26 and this combination constitutes an energy absorption mechanism for the vehicle 21. Thus, the impact element 23, armature 26 and crush can 25 are all secured to the vehicle 21 through its chassis 30.

The second impact element 24 is laterally displaceable in the direction of the depicted arrow heads between a normal configuration N and a retracted configuration R.

In the normal configuration N, the impact element 24 has a surface 9n which is consistent with the vehicle 21 aesthetic profile constituted by the grille 28 in association with the first impact element 23 of the bumper arrangement. In such circumstances, it will be appreciated that a broad impact front is provided for the vehicle 21 which extends from a relatively low height in order to ensure a large off-road vehicle 1 has improved bumper compatibility with lower normal height road vehicles.

In the retracted configuration R (dotted line), the second impact element 24 is retracted rearwardly within the vehicle 21 in order to ensure a suitably acceptable approach angle A-A is achieved for the vehicle 21 to allow off-road activity in rough terrain. It will be appreciated in the retracted configuration R, the vehicle 21 substantially only presents the first impact element 23 at the periphery of the vehicle 21. Thus, a much narrower and higher bumper is provided for the vehicle 21 which is less compatible with a normal height road vehicle. However, it will also be appreciated off-road movement is less likely to precipitate 10 collision with a normal height road vehicle.

1 Displacement of the second impact element 24 between the normal configuration N and the retracted configuration R can be achieved in a multitude of conventional manners. For example, a simple latched slot could be provided with manual displacement between respective latch positions within the slot consistent with the normal configuration N and the retracted configuration R. Alternatively, a driven screw or ratchet mechanism may be used to displace the second impact element 24 between the normal configuration N and the retracted configuration R.

As indicated previously with regard to Figure 1, it is important that the bumper arrangement constituted by impact elements 23, 24 is adequately coupled into the energy absorption mechanisms of the vehicle 21. Thus, the second impact element 24 is secured to an adjunct 31 to the chassis 30. The adjunct 31 provides a mounting upon which the second impact element 24 is secured through respective bumper armature and crush can components. Typically, the whole assembly of element 24 with its energy absorption couplings, armature and crush can move into the adjunct 31 or moves together in a lateral direction between the normal configuration N and the retracted configuration R.

Those skilled in the art will appreciate that the bumper arrangement comprising respective first and second impact elements will typically be formed from deformable materials in order to provide themselves a degree of energy absorption under collision impact. Thus, the respective first and/or second impact elements may be made from metal or plastic 5 and be foam-filled or moulded.

Although axial displacement has been described above, it will be understood that rotation about a pivot between a first impact element and a second impact element can be arranged to achieve a similar displacement between a normal configuration and a raised/retracted configuration. However, appropriate coupling to existing collision energy absorbing mechanism may be more difficult and care must be taken to prevent reverse rotation about that pivot during collision.

Claims

-9CLAIMS

1 A vehicle bumper arrangement comprising a first impact element and a second impact element secured together with displacement means to provide an aesthetically consistent profile for a vehicle to which the bumper arrangement is attached, said first and said second impact elements being relatively displaceable by said displacement means between a normal configuration for road use and a retracted configuration more suitable for off-road vehicle use, said normal configuration presenting both said first and said second impact elements for impact compatibility with other road vehicles of a lower bumper height whilst said retracted configuration presents substantially only said first impact element for impact and with said second impact element relatively displaced with regard to said first impact element to improve the approach angle of a vehicle to which the vehicle bumper arrangement is attached in comparison with said normal configuration.

2. A vehicle bumper arrangement comprising an impact element secured to displacement means to provide an aesthetically consistent profile for a vehicle to which the bumper arrangement is attached, said impact element being relatively displaceable by said displacement means between a normal configuration for road use and a raised or retracted configuration more suitable for off-road vehicle use, said normal configuration presenting said impact element for compatibility with other road vehicles of a lower bumper height whilst said raised configuration substantially presents said impact element to improve approach angle of a vehicle to which the vehicle bumper arrangement is attached in comparison with the normal configuration.

3. An arrangement as claimed in Claim 1, wherein the displacement means is arranged to achieve axial, either longitudinal or lateral, displacement between said first impact element and said second impact element.

4. An arrangement as claimed in Claim 1, wherein the displacement means is arranged to allow rotary displacement about a pivot between said first and said second impact element.

5. An arrangement as claimed in Claim 1 and any claim dependent thereon, wherein a grille portion is arranged to fill any space between said first and said second impact elements when in the normal configuration in order to provide said aesthetically consistent profile for a vehicle to which the arrangement is attached.

6. An arrangement as claimed in any preceding claim, wherein the displacement means is manually operable.

I

7. An arrangement as claimed in any of Claims I to 5, wherein the displacement means is mechanical in order to displace said first and/or said second impact element between said normal configuration and said raised or retracted configuration.

8. An arrangement as claimed in any preceding claim, wherein the arrangement is coupled to said vehicle collision energy absorption mechanisms such as crush cans.

9. An arrangement as claimed in any preceding claim, wherein any said impact element comprises several segmented components in order to facilitate controlled deformation of said impact element under collision impact.

10. An arrangement as claimed in any preceding claim, wherein any said impact element is made from a deformable material to facilitate energy absorption therein during impact.

11. A vehicle bumper arrangement substantially as hereiribefore described with reference to Figure 1.

12. A vehicle bumper arrangement substantially as hereinbefore described with reference to Figure 2.

13. A motor vehicle including a vehicle bumper arrangement as claimed in any preceding claim.