GB2337028A - A pedestrian bar arrangement - Google Patents

Abstract

A pedestrian bar arrangement (2) secured to a motor vehicle (1) such that a bar assembly (4) is displaced from an upper configuration to a lower configuration. Thus, the vehicle (1) maintains sufficient approach angle to avoid ground fouling in off-road driving. However, in the lower configuration, the bar arrangement (2) presents a lower contact to a pedestrian during a collision. Displacement between the upper configuration and the lower configuration may either be gravitational or propulsive under mechanical slide displacement means.

Description

2337028 A PEDESTRIAN BAR ARRANGEMENT The present invention relates to a

pedestrian bar arrangement for pedestrian safety and more particularly to pedestrian safety with regard to frontal impact with road vehicles.

There is a requirement to continuously improve motor vehicle safety in terms of vehicle -to -vehicle collisions and with regard to vehicle pedestrian collisions. The present invention relates particularly to collisions between a vehicle, and more especially off-road 4x4 vehicles, with a pedestrian.

It will be noted that off road vehicles generally have a high ground clearance and approach angle. By such means off road vehicles avoid socalled grounding upon uneven and rough terrain.

Such high approach angles inherently presents the bumper or bar assembly of that vehicle at a relatively high position upon a pedestrian leg. Thus, when subjected to a collision, a pedestrian's leg is bent in an unacceptable manner. Clearly, any collision between a motor vehicle and a pedestrian will injure that pedestrian. However, by control of the nature of the impact and deformation, the severity of such injury can be reduced.

Typically, acceptable safety levels are proposed by appropriate regulatory authorities through pedestrian safety legislation. Thus, for example, there may be a limit to the angle of bend between the upper and lower halves of a pedestrian's leg. This limit may be set at 150 as determined by a test impacter propelled at the front of a motor vehicle with a predetermined velocity, ie. 40 kph.

A high riding off-road vehicle has difficulty achieving such a safety level due to the high point of contact with the pedestrian's leg. A solution is to provide a bumper contact area with a pedestrian at a lower level. Such lower contact will reduce impact knee bending angle to an acceptable degree. Unfortunately, with an off road vehicle, it is necessary to retain the approach angle and ground clearance necessary to avoid contact with rough terrain. In an off road vehicle, it will generally be necessary to ensure that there is an approach angle for the bumper in the order of 40 whilst in an on road, highway situation, the approach angle should be in the order of 15.

Furthermore, due to the indeterminate nature of where contact will take place, it is necessary that the full width of the vehicle is presented for contact in a collision with a pedestrian.

In addition to providing a lower contact surface for acceptable pedestrian leg impact, energy must be absorbed through such a bumper arrangement. Thus, somewhere in the order of 80 to 100 mm of bumper deformation is required. Modern vehicles include a bumper or bar assembly made from a metal or plastics material which may be sufficiently deformable to absorb pedestrian collision energy when in contact therewith.

Over recent years there has been an increased use of notionally off road or 4x4 type vehicles for normal highway use.

It is an object of the present invention to improve pedestrian safety during a collision through an appropriate pedestrian bar arrangement to limit leg bend in such a collision.

In accordance with the present invention there is provided a pedestrian bar arrangement for a motor vehicle, the arrangement comprising a bar assembly mounted in slide means to allow displacement between an upper configuration and a lower configuration, said upper configuration presenting said bar assembly above an acceptable approach angle for a vehicle to which the arrangement is attached whilst said lower configuration presents said bar assembly at a lower position for contact upon a pedestrian's leg during a coWsion, said arrangement including displacement means to determine displacement between said upper and said lower configuration.

The bar assembly may be substantially planar and perpendicular to the direction of vehicle travel. The bar assembly may be of a bull-bar type.

The slide means may be passive or propulsive. Furthermore, rack and pinion or ratchet type arrangements may be used in addition to simple slippage in guides.

An embodiment of the present invention will now be described by way 5 of example only with reference to the accompanying drawings, in which:

Figure 1 illustrates in pictorial cross-section a pedestrian bar arrangement attached to a vehicle in an upper configuration; and Figure 2 illustrates in pictorial cross-section the arrangement illustrated in Figure 1 in a lower configuration.

With off road vehicles, it is important that the approach angle is sufficient to avoid fouling between the vehicle and rough ground or terrain over which the vehicle passes. Thus, as depicted in Figure 1, a motor vehicle 1 includes a pedestrian bar arrangement 2 in an upper configuration. In such an upper configuration, the arrangement 2 is above the vehicle 1 approach angle depicted as broken line 3. Thus, the arrangement 2 will not foul or "ground" as the vehicle 1 is driven over rough terrain.

In Figure 2, the arrangement 2 is displaced into a lower configuration which extends below the approach angle 3 of the vehicle 1. This lower configuration is such that the arrangement 2 will be presented at a lower position to a pedestrian in collision. Thus, if the vehicle 1 should collide with a pedestrian and in particular that pedestrian's leg, the arrangement 2 win broadly engage that pedestrian's leg from a relatively low position. Such lower engagement will. limit leg impact bend with a reciprocal reduction in injury to that pedestrian.

The arrangement 2 comprises a bar assembly. 4 mounted in a slide mechanism 5. Thus, typically the whole bar assembly 4 is displaced from its upper configuration (Figure 1) to its lower configuration (Figure 2). Furthermore, the bar assembly 4 comprises a planar element which is substantially perpendicular to the direction of travel of the vehicle 1.

The slide mechanism 5 can provide either passive or propulsive displacement.

In a passive displacement, simple gravitational weight of the bar assembly 4 will precipitate displacement between the upper configuration and the lower configuration. Furthermore, with passive displacement the bar assembly may be released from its upper off-road configuration to its lower configuration through "bump" release of a latch mechanism by a hand -6 action. There is a vice versa displacement to return the assembly 4 back to upper, highway configuration. However, such gravitational displacement of the bar assembly 4 may be too slow.

The slide mechanism preferably is propulsive in order to drive displacement of the bar assembly 4 into its lower configuration. Such propulsion may be mechanical, ie. geared or involve a hydraulic or pneumatic ram.

The bar assembly 4 provides an appropriate abutment surface to a pedestrian during a collision to e nsure a broad contact with that pedestrian's leg. However, collision contact balance within the bar assembly 4 is important. Thus, it may be preferable, as depicted in Figure 2, that the bar assembly 4 is mounted relatively centrally. Such central location will ensure a balanced contact with a pedestrian and so avoid twisting of the bar assembly 4 during a collision.

The motor vehicle 1 will react in a conventional manner with regard to crumple zones. Thus, general vehicle safety will not be diminished by inclusion of the present bar assembly arrangement coupled to those crumple zones.

j - ' : P 17 The bar assembly 4 can take the from of a bull-bar type grid. Thus, horizontal and vertical tubes are appropriately secured together to create a planar grid as the bar assembly 4.

As indicated above, it is preferable that the bar assembly 4 has a resilient nature in order to more appropriately utilise the energy absorption of the bar assembly 4 through deformation under collision.

The present pedestrian bar arrangement 2 is of particular application with regard to off road vehicles. However, such off road vehicles inherently are subject to significantly harsher treatment than highway vehicles.

Furthermore, whilst off road the likelihood of collision with a pedestrian is diminished. Thus, the arrangement 2 can be either manually or automatically lockable to prevent displacement from its upper configuration whilst in an off road driving state. Automatic deployment may utilise sensors within the vehicle 1 when a transition from off-road to highway or vice versa is determined.

The arrangement 2 has substantially two operational configurations as depicted respectively in Figures 1 and 2. In a passive displacement system where the bar assembly 4 is displaced using its weight under gravitational action, it will be understood return to the upper configuration may be achieved by a simple manual lifting action. However, with regard to a propulsive displacement system, return to the upper configuration may be achieved by reversing the propulsion mechanism. Such reversal of the propulsion mechanism, ie. ram or gear mechanism could be actuated from within the motor vehicle.

As pedestrian safety is the objective of the arrangement 2, the bar assembly 4, in association with the slide dispacement mechanism 5, is configured to achieve the most desirable contact with a pedestrian. Thus, respective proportions of the bar assembly 4 may be provided with differential deformation resistance and so transient presentations during collision with a pedestrian. Such differential deformation may be achieved through appropriate choice of materials, their thickness and inclusion of deformation resistance elements and structures.

- Finally, as an alternative to use of a fixed dimensioned bar assembly 4, with a slide displacement mechanism 5, the bar assembly 4 itself may be expandable in order to vary its height dimension. The assemby 4 expansion itself provides the upper configuration (normal sized assembly) displacement to the lower configuration (expanded sized assembly). The dimension varying expansion or contraction of the assembly 4 may be downward or upward. In such circumstances, the assembly 4 itself win include its own internal slide displacement mechanism to precipitate the required dimension variation for upper and lower configuration presentation. Typically, concentric bar segments will slide past one another in order to expand or contract the assembly 4 dimension.

Claims (8)

1. A pedestrian bar arrangement for a motor vehicle, the arrangement comprising a bar assembly mounted in slide means to allow displacement between an upper configuration and a lower configuration, said upper configuration presenting said bar assembly above an acceptable approach angle for a motor vehicle to which said arrangement is attached whilst said lower configuration presents said bar assembly at a lower position for contact upon a pedestrian's leg during a collision, said arrangement including displacement means to determine displacement between said upper and said lower configuration.

2. An arrangement as claimed in Claim 1, wherein the bar assembly is substantially planar and mounted within a motor vehicle to be substantially perpendicular to the direction of vehicle travel.

3. An arrangement as claimed in Claim 1 or Claim 2, wherein the slide means is passive in that the bar assembly is arranged to be displaced due to the gravitational force of its own weight within the slide means under determination from the displacement means.

An arrangement as claimed in Claim 1 or Claim 2, wherein the slide means is propulsive to displace the bar assembly between the upper configuration and the lower configuration as determined by the displacement means.

5. An arrangement as claimed in any preceding claim, wherein the bar assembly is of a bull-bar type.

6. An arrangement as claimed in any preceding claim, wherein the bar assembly is configured to allow dimensional variation in order to provide displacement between the upper configuration and lower configuration.

7.

An arrangement substantially as hereinbefore described with reference to the accompanying drawings.

8. A motor vehicle including a pedestrian bar arrangement as claimed in any preceding claim.