GB2388341A

GB2388341A - Auxiliary front bumper lowerable on collision sensing

Info

Publication number: GB2388341A
Application number: GB0210443A
Authority: GB
Inventors: Land Yngve H; Sture Andersson
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 2002-05-07
Filing date: 2002-05-07
Publication date: 2003-11-12
Anticipated expiration: 2022-05-07
Also published as: GB0210443D0; GB2388341B

Abstract

An auxiliary front bumper 6 for a vehicle is lowered when a collision occurs or is imminent. The bumper 6 is stored and normally located behind the front extremity 5 of the vehicle, preferably above a tangent from the lower front of the vehicle to the lower halves of the front wheels, and comprises a beam 6 which extends across the vehicle's width and which may be connected to a ratchet 22 by pivotal link arm 23. When a device such as an infra-red or radar sensor 19 detects the proximity of another vehicle, the bumper 6 is lowered to a position preferably at least 20cm, most preferably 25-27 cm above the road and 20-25 cm behind the vehicle's front extremity 5. A pyrotechnic device 16, the release of a compressed spring or the actuation of an over-dead-centre linkage (see figs 5 & 6) are preferable means of lowering the bumper 6, which may thus reduce the severity of a high vehicle impacting the side of a conventional car.

Description

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DESCRIPTION OF INVENTION

"IMPROVEIVIENTS IN OR RELATING TO A SAFETY DEVICE"

THE PRESENT INVENTION relates to a safety device, and more particularly relates to a safety device mounted on a motor vehicle.

Many motor vehicles, such as motor cars have a relatively strong floor pan or lower part of the chassis, which is adapted to crumple in an energy= absorbing manner in the event that an impact should occur, but the side parts of the vehicle, for example in the regions of the doors of the vehicle, at a level above the floor pan, are very weak.

Thus, if a conventional motor car is subjected to a side impact from another vehicle which is a "higher" vehicle, such as a typical four-wheel drive or off-road vehicle, the "high" vehicle can strike a very weak port of the conventional motor car with the result that the "high" vehicle may intrude substantially into the motor car, and thus there is severe risk of injuries occurring to the occupants of the conventional motor cart According to this invention there is provided a safety device for a vehicle, the device comprising a beam forming an auxiliary bumper, and a moving mechanism to lower the beam from an initial position to an operative

l position in which the auxiliary bumper is beneath and behind the frontmost part of the vehicle, the safety device further comprising a sensor arrangement adapted to sense an impact or an impact situation, and to actuate the moving mechanism, the beam, when in the operative position, being adapted to withstand an impact with another vehicle.

Conveniently, when the device is mounted on a vehicle, the beam is a transverse beam that extends over substantially the entire width of the vehicle.

Preferably the entire beam, when in the initial position, is located above a notional ramp plane tangential to the lower front part of the vehicle and the lower front part of the front lyre of the vehicle.

Conveniently the beam is in the operative position, the lower edge thereof is at least 20 centimetres above the ground supporting the vehicle.

Advantageously the lower edge of the beam, when in the operative position, is 25 to 27 centimetres above the ground supporting the vehicle.

Conveniently when the beam is in the operative position, the front face of the beam is at least] 5 centimetres behind the front-most part of the vehicle.

Preferably when the beam is in the operative position, the front face of the beam is 202 to 25 centimetres behind the front-most part of the vehicle.

Advantageously the moving mechanism comprises an expandable metal bellows containing a pyrotechnic charge, the sensor arrangement being adapted to ignite the pyrotechnic charge to cause the bellows to expand.

Alternatively the moving mechanism includes a spring, the spring being retained in a compressed condition and being released by a release mechanism controlled by the sensor arrangement.

In one embodiment the beam is adapted to move substantially vertically from the initial position to the operative position.

Conveniently a substantially vertical guide arm is provided, the beam being mounted on a sleeve which is movable along the vertical guide arm.

Preferably the beam is associated with a reinforcing arrangement, including a rearwardly directed reinforcing arm.

In an alternative embodiment the beam is pivotally mounted, and the moving mechanism is adapted to move the beam pivotally from the initial position to the operative position.

Preferably the moving mechanism includes an over-dead-centre linkage.

Advantageously the sensor arrangement comprises a sensor responsive to contact between a front part of the vehicle and another vehicle.

Conveniently the sensor arrangement comprises a proximity sensor adapted to sense the proximity of another vehicle.

In one embodiment the proximity sensor is a radar sensor.

In an alternative embodiment the proximity sensor comprises an infra-

red sensor.

Conveniently the sensor arrangement further comprises a speed sensor, the sensor arrangement being adapted so that the proximity sensor is inhibited at speeds lower than a certain predetermined speed.

In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invention will now be described, by way of example, with reference to the accompanying drawings in which: FIGURE I is a diagrammatic view illustrating a conventional motor car, being subjected to a side impact from a relatively "high" vehicle, which is provided with a safety device in accordance with the invention, the safety device being in an initial or retracted position.

FIGURE 2 is a view corresponding to Figure 1 illustrating the "high" vehicle provided with a safety device in accordance with the present invention, with the safety device being in the deployed condition, FIGURE 3 is a diagrammatic view illustrating components of one embodiment of a safety device in accordance with the invention prior to deployment, FIGURE 4 is a view corresponding to part of Figure 3 illustrating the safety device of Figure 3 after deployment,

FIGURE 5 is a diagrammatic view illustrating components of an alternative form of safety device in accordance with the invention, prior to deployment, and FIGURE 6 is a view of the safety device of Figure 5 after deployment.

Referring initially to Figure 1 of the accompanying drawings, a conventional motor car 1 is illustrated. The motor car 1 has a relatively strong floor pan or sub-chassis 2 located a predetermined distance above the road.

The side panels 3 of the motor vehicle are relatively weak.

The conventional motor car 1 is illustrated being subjected to a side impact from a "high" vehicle 4' such as a four-wheel drive or off-road vehicle.

The high vehicle 4 is provided with a bumper region 5 which is located above the level of the floor pan 2 of the conventional motor car 1. It is to be appreciated that in a side impact situation of this type the bumper 5 of a high vehicle 4 may pass relatively easily through the side panels 3 of the conventional motor car, experiencing very little resistance. The entire front part of the high vehicle may thus pass over the floor pan 2 of the conventional motor car, and the high vehicle may intrude by a substantial distance into the conventional motor car. Thus there is a very substantial risk of injury occurring to the occupants of the ordinary motor car 1. However, the high vehicle 4 is provided with a safety device in accordance with the invention. In Figure 1 the safety device is in the initial or retracted position and this is not visible.

Referring now to Figure 2 of the accompanying drawings, the high vehicle 4 is now illustrated with the safety device in accordance with the invention in the deployed condition. The safety device includes a transverse beam 6 which is capable of being moved from an initial stored position to a

lowered or operative position, in which it constitutes an auxiliary bumper, the lowered or operative position being illustrated in Figure 2. When the beam 6 is in the lowered or operative position, it is located beneath and behind the front-

most part of the high vehicle 4, and, in the illustrated situation, is substantially aligned with the floor pan 2 of the conventional motor car 1. The beam 6, when in the operative position, is adapted to withstand an impact with another vehicle, such as the conventional motor car 1. It is to be appreciated, therefore, that in the illustrated side impact situation, whilst the front part of the high vehicle 4 will intrude by a certain distance into the interior of the conventional motor car 1, the auxiliary bumper formed by the beam 6 will, shortly after commencement of the impact, engage with the floor pan 2 of the conventional motor car 1. The floor pan of the conventional motor car 1 may absorb at least part of the energy of the impact, and this will serve to reduce or minimise the degree of intrusion of the high vehicle 4 into the conventional motor car 1, thus reducing or minimising the risk of injuries occurring to the occupants of the conventional motor car 1.

The transverse beam or auxiliary bumper 6, in the operative position as in Figure 2 extends beneath the "ramp plane'' 7 of the high vehicle 4. The ramp plane is a notional line which extends from the lower-most and foremost part of the vehicle, and the lower-most and foremost part of the front wheel and effectively defines the limiting angle of a ramp that the vehicle can climb from an initial horizontal surface. It is to be appreciated that if the auxiliary bumper or beam 6 was always in the operative position, in which it extends across the normal ramp plane of the vehicle, the capability of the vehicle, especially in rough terrain would be compromised. Thus, in the described embodiments of the invention the beam is movable from an initial position, in which the beam is located above the ramp plane in a position in which it is preferably substantially

concealed by the bodywork of the high vehicle, to the operative position in response to signals from one or more sensors.

Turning now to Figures 3 and 4, the component parts of one particular embodiment of the invention will now be described.

Referring initially to Figure 3, a substantially rigid guide arm 10 is provided which depends from a fixed part 11 of the chassis of the high vehicle 4. Slidably mounted on the guide arm lO is a slideable sleeve 12 which carries a supporting leg 13 which supports, at its lower end, the transverse beam or auxiliary bumper 6. Two or more parallel guide arms 10 and associated sleeves 12 may be provided spaced-apart across the width of the high vehicle 4.

Each guide arm and sleeve may be covered by a protective gaiter, to prevent mud or dirt clinging to the guide arm. An arrangement is provided adapted to move the or each sleeve 12, and thus the bumper 6, downwardly from an initial upper position to a downward or operative position. The arrangement for moving the sleeve 12 comprises an expandable metal bellows l 4 located between the fixed part I 1 of the chassis of the vehicle, and an actuating lug 15 extending from the supporting leg 13. Contained within the expandable bellows 14 is a pyrotechnic charge 16 adapted to be actuated by a control arrangement 17.

In the described embodiment the contro! arrangement 17 receives signals from a plurality of sensors. A first sensor, 18, is an impact sensor mounted on the ordinary or conventional front bumper 5 of the vehicle. A second sensor is a radar sensor 19, or some other form of proximity sensor located adjacent the front of the vehicle and adapted to sense the proximity of another vehicle. The control arrangement 17 may also receive an input signal from the speedometer20 of the motor vehicle, so that the proximity sensor may be

inhibited from actuation when the vehicle is travelling at slow speed, such as in a car park, since otherwise spurious signals may be generated by the proximity sensor, and the auxiliary bumper or beam 6 may be moved to the operative position inappropriately.

In the embodiment illustrated in Figure 3, an additional arrangement is provided to give added strength to the auxiliary bumper 6, when the bumper 6 is in the operative position. The additional arrangement comprises a housing 21 containing a pawl which is slidably moveable along a ratchet 22, the ratchet being secured to the motor vehicle. The housing 21 is connected by means of a pivotal connecting rod 23, to the beam or auxiliary bumper 6.

When an impact is sensed by the sensor 18, or when a vehicle is sensed by the radar or proximity sensor 19, and the vehicle has a certain predetermined minimum speed, the control arrangement 17 will actuate the pyrotechnic device 16, thus inflating the inflatable bellows 14 and causing the bellows to expand. The expanding bellows 14 will drive the sleeve 12 down the support arm 10, thus moving the beam or auxiliary bumper 6 from an initial position to a lowered or operative position. As the bumper moves downwardly, so the pivotal link arm 23 will draw the housing 21 containing the pawl along the ratchet 22. The pawl will then engage the ratchet and prevent the housing 21 moving back towards its initial position.

It will be appreciated that the transverse beam or bumper has thus been moved from an upper, or initial position, to a lowered or operative position.

When in the operative position the bumper is capable of withstanding a substantial force, such as the force that would be applied to the auxiliary bumper 6 on impact with a conventional motor car, due to the strength of the supporting arm lO, and due to the reinforcement provided by the link arm 23,

and the associated housing 21 containing the pawl which engages the ratchet 22.

Following deployment of the auxiliary bumper as described above' it will be possible to return the bumper to the initial position by disconnecting the pawl from the ratchet 22, and by replacing the expanded metal bellows 14 with a fresh metal bellows.

Whilst Figures 3 and 4 illustrate one mechanism that may be adopted to move the transverse beam or auxiliary bumper 6 from an upper position to a lower or operative position, alternative mechanisms may be utilised. Figures 5 and 6 illustrate one such mechanism in which the transverse beam or bumper 6 is mounted on a support leg 30, the upper end of which is pivotally connected 31 to a secure point in the motor vehicle. The support leg 30 is pivotally connected, by a pivot 32 to one end of an over-dead-centre linkage comprising arms 33, 34. The arms 33, 34 are pivotally connected by a pivot 35, and the free end of the arm 34 is pivotally connected to a fixed part of the motor vehicle by means of a pivot 36.

In an initial condition of the arrangement, as shown in Figure 5, the support leg 30 is in an upper or inclined condition, and the two arms 33, 34, of the over-dead-centre linkage are inclined to each other. An arrangement such as an expandable metal bellows 37 is provided adapted to move the point of pivotal interconnection 35 of the two arms 33, 34 of the over-dead-centre linkage in response to a signal from a control arrangement such as the control arrangement 17 as described above. A stop 38 is provided, positioned to be engaged by the linkage after it has passed the dead-centre position.

As can be seen in Figure 6, when the metal bellows expands, moving the point of pivotal interconnection 35 of the two arms 33, 34 of the overdead-

centre linkage, the support leg of the transverse beam is moved pivotally about the pivotal mounting 31 to a substantially vertical position. The over-dead-

centre linkage passes through a dead-centre condition, and then the point of pivotal connection 35 engages the stop 38. The transverse beam or auxiliary bumpers is thus moved to the operative position and is then capable of withstanding the forces that may be applied to it during an impact, such an impact with a conventional motor car, as the forces applied to the beam or auxiliary bumper 6 will merely drive the linkage more firmly into engagement with the stop 38.

Following deployment the described components may be returned to their initial positions, and a fresh metal bellows may be installed.

In the described embodiments of the invention the auxiliary bumper or beam 6 extends over substantially the entire width of the vehicle. When the beam is in the operative position, the lower edge of the beam is preferably 25-

27 centimetres above ground, and also when the beam is in the operative position, the front face of the beam is at least 15 centimetres behind the front-

most part of the vehicle. Thus, when an impact is sensed by the sensor 18 provided on the bumper 5, there is a period of time equivalent to the time taken by the vehicle to cover at least 15 centimetres in which the safety device may be deployed, and the auxiliary beam or bumper 6 may be moved to the operative position. Preferably when the beam is in the operative position, the front face of the beam is 20 to 25 centimetres behind the front-most part of the vehicle.

Whilst reference has been made to the use of a radar sensor, an infra-red sensor may be utilised as the proximity sensor.

The described embodiments each include an expandable bellows. Such a bellows may be replaced by a compressed spring, the spring being retained in a compressed condition and being released by a release mechanism controlled by the sensor arrangement.

In the present Specification "comprises" means "includes or consists of"

and "comprising" means "including or consisting of".

The features disclosed in the foregoing description, or the following

Claims, or the accompanying drawings, expressed in their specific forms or in

terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS:

1. A safety device for a vehicle, the device comprising a beam forming an auxiliary bumper, and a moving mechanism to lower the beam from an initial position to an operative position in which the auxiliary bumper is beneath and behind the front-most part of the vehicle, the safety device further comprising a sensor arrangement adapted to sense an impact or an impact situation, and to actuate the moving mechanism, the beam, when in the operative position, being adapted to withstand an impact with another vehicle.

2. A device according to Claim 1 when mounted on a vehicle wherein the beam is a transverse beam that extends over substantially the entire width of the vehicle.

3. A device according to Claim 2 wherein the entire beam, when in the initial position, is located above a notional ramp plane tangential to the lower front part of the vehicle and the lower front part of the front tyre of the vehicle.

4. A device according to Claim 2 or Claim 3 wherein, the beam is in the operative position, the lower edge thereof is at least 20 centimetres above the ground supporting the vehicle.

5. A device according to Claim 4 wherein the lower edge of the beam, when in the operative position, is 25 to 27 centimetres above the ground supporting the vehicle.

6. A device according to any one of Claims 2 to 5 wherein, when the beam is in the operative position, the front face of the beam is at least 15 centimetres behind the front-most part of the vehicle.

7. A device according to Claim 6 wherein, when the beam is in the operative position, the front face of the beam is 20 to 25 centimetres behind the front-most part of the vehicle.

8. A device according to any one of the preceding Claims wherein the moving mechanism comprises an expandable metal bellows containing a pyrotechnic charge, the sensor arrangement being adapted to ignite the pyrotechnic charge to cause the bellows to expand.

9. A device according to any one of Claims I to 7 wherein the moving mechanism includes a spring, the spring being retained in a compressed condition and being released by a release mechanism controlled by the sensor arrangement.

10. A device according to any one of Claims 1 to 9 wherein the beam is adapted to move substantially vertically from the initial position to the operative position.

11. A device according to Claim 10 wherein a substantially vertical guide arm is provided, the beam being mounted on a sleeve which is movable along the vertical guide arm.

12. A device according to Claim 9 or 10 wherein the beam is associated with a reinforcing arrangement, including a rearwardly directed reinforcing arm.

13. A device according to any one Claims 1 to 9 wherein the beam is pivotally mounted, and the moving mechanism is adapted to move the beam pivotally from the initial position to the operative position.

14. A device according to Claim 13 wherein the moving mechanism includes an over-dead-centre linkage.

15. A device according to any one of the preceding Claims wherein the sensor arrangement comprises a sensor responsive to contact between a front part of the vehicle and another vehicle.

16. A device according to any one of the preceding Claims wherein the sensor arrangement comprises a proximity sensor adapted to sense the proximity of another vehicle.

17. A sensor arrangement according to Claim 16 wherein the proximity sensor is a radar sensor.

18. A device according to Claim 16 wherein the proximity sensor comprises an infra-red sensor.

19. A device according to any one of Claims 15 to 18 wherein the sensor arrangement further comprises a speed sensor, the sensor arrangement being adapted so that the proximity sensor is inhibited at speeds lower than a certain predetermined speed.

20. A safety device for a vehicle substantially as herein described with reference to and as shown in Figures I to 4 of the accompanying drawings.

21. A safety device for a vehicle substantially as herein described with reference to and as shown in Figures 1 to 4 as modified by Figures 5 and 6 of the accompanying drawings.

22. Any novel feature or combination of features disclosed herein.