GB2411866A

GB2411866A - A pedestrian safety device

Info

Publication number: GB2411866A
Application number: GB0405160A
Authority: GB
Inventors: William Murray Mclundie
Original assignee: Ford Global Technologies LLC
Current assignee: Ford Global Technologies LLC
Priority date: 2004-03-08
Filing date: 2004-03-08
Publication date: 2005-09-14
Also published as: GB0405160D0

Abstract

A safety device for a motor vehicle is disclosed in which an elongate spring member 20, 120 is used to provide a force used to raise a rear edge of a bonnet 15,115 when a pedestrian impact is occurring or is likely to occur. The elongate spring member is in the form of an arcuate composite bow 20,120 which is deformed from a relaxed arcuate shape to a less arcuate shape by applying a load to the composite bow 20, 120 causing it to adopt a deformed state in which it is held by a latching means 130. When the bonnet 15, 115 needs to be raised, the latching means 130 is released and the composite bow 20, 120 returns to its relaxed state thereby releasing the energy stored in it to raise the bonnet 15, 115.

Description

241 1 866 A Pedestrian Safety Device This invention relates to motor

vehicles and in particular to a pedestrian safety device for a motor vehicle.

It is known to provide a safety device for a motor vehicle which is operable to raise a rear end of a bonnet of a motor vehicle when the motor vehicle is involved in a collision with a pedestrian. The raising of the bonnet is very useful in improving safety in that it reduces the risk of contact between the head of a pedestrian thrown onto the bonnet and hard impact points under the bonnet such as the engine.

It has previously been proposed to use various devices to raise the bonnet including airbags, pyrotechnic devices and linkages between the impact area and the lifting means.

It is a problem with such prior art devices that they add complexity to the motor vehicle, increase the weight and potentially increase the cost.

It is an object of this invention to provide an improved safety device for a motor vehicle which is simple in construction and economical to manufacture.

According to the invention there is provided a safety device for a bonnet of a motor vehicle comprising an elongate spring member to raise a rear edge of the bonnet in the event of a collision with a pedestrian wherein the elongate spring member is held in a deformed state during normal use of the motor vehicle and is released to a relaxed state to raise the rear edge of the bonnet.

Preferably, the elongate spring member is made from a plastic composite material.

The elongate spring member may be of an arcuate form when in the relaxed state. - 2

The elongate spring member may be deformed to a less arcuate form when in the deformed state. The elongate member may be of a substantially flattened form when in the deformed state.

Advantageously, the elongate member may extend transversely across the motor vehicle to which it is fitted.

The elongate spring member may be attached to part of the body structure of the motor vehicle and may react against the bonnet to raise the rear edge of the bonnet. In which case, each of the distal ends of the elongate spring member may have a slot formed therein used to slidingly attach the elongate spring member to the body structure of the motor vehicle.

Alternatively, the elongate spring member may be attached to the bonnet of the motor vehicle and may react against part of the body structure of the motor vehicle to raise the rear edge of the bonnet. In which case, the elongate spring member may be engaged at each end with a respective guide formed by inner and outer panel of the bonnet so as to slidingly attach the elongate spring to the bonnet.

The elongate spring member may be held in the deformed state by one or more latching means.

The or each latching means may be connected to a sensor system used to determine a pedestrian impact criterion selected from one of actual impact with a pedestrian and predicted impact with a pedestrian and is released when the pedestrian impact criterion is met. Both criteria may be used and the latching means may be released when either of the criteria is met.

Accordingto the invention the safety device for a bonnet of a motor vehicle may comprise a spring member made from a plastic composite material to raise a rear edge of the bonnet in the event of a collision with a pedestrian wherein the spring member is held in a deformed state during normal use of the motor vehicle and is released to a relaxed state to raise the rear edge of the bonnet.

The invention will now be described by way of example with reference to the accompanying drawing of which: Fig.1 is a side view of part of the front of a motor vehicle having a pedestrian safety device according to a first embodiment of the invention; Fig.2 is a front view of the motor vehicle shown in Fig.1 with the bonnet removed; Fig.3 is a pictorial partial side view of the front of the motor vehicle shown in Fig.1 with the bonnet removed; Fig.4 is a split plan view of a spring forming part of the pedestrian safety device according to the first embodiment of the invention; Fig.5a is a pictorial partial side view of the front of a motor vehicle having a pedestrian safety device according to a second embodiment of the invention; and Fig.5b is a cross-section on the line x- x on Fig.5a.

With reference to Figs. 1 to 4 there is shown a motor vehicle 10 having a body structure 11 defining an engine compartment 12 separated from a passenger compartment of the motor vehicle 10 by a bulkhead 13. A front hinged bonnet 15 is fastened to the body structure 11 by means of hinges (not shown) and is held in a closed position by a releasable locking mechanism (not shown). An elongate spring member in the form of a plastic composite bow 20 is attached to the body structure 11 of the motor vehicle 10 near to the bulkhead 13. The use of a plastic composite material for the spring member is - 4 - particularly advantageous in that such materials can store energy for long periods of time as they do not tend creep to any great extent unlike metallic materials. It would be possible to use a metallic spring but in this case the material would need to chosen carefully in order to produce a spring with low weight and low creep.

As shown in Fig.2 the composite bow 20 in a relaxed state is of an arcuate form and has a thickened end portion 21 at each end in which is formed a slot 22. The slots 22 are used to slidingly attach the composite bow 20 to the body structure 11 by means of engagement with a pair of pins (not shown) fixed to the body structure 11. There being one pin on the left side of the motor vehicle 10 and one pin on the right side of the motor vehicle 10.

As can be seen the composite bow 20 extends transversely across the motor vehicle that is to say it extends from a position near to the left side of the engine compartment 12 to a position near to the right side of the engine compartment 12. This is useful in that it enables the composite bow 20 to be packaged in such a way that it does not affect or interfere with the crush performance of the motor vehicle 10.

During normal use of the motor vehicle 10, the composite bow 20 is held in a deformed state by a latching means (not shown). In the deformed state, and as shown in Fig.3, the composite bow 20 is deformed to a less arcuate form and in the embodiment shown is deformed to a substantially flattened form. During assembly of the composite bow 20 to the motor vehicle 10 the slots 22 are engaged with the two pins fixed to the body structure 11 and the composite bow 20 is then deformed by applying a force to the composite bow 20 until the latching means can be engaged. The composite bow 20 then remains held in this deformed state until it is required to raise the rear edge of the bonnet 15. It will be appreciated that the deformation of the composite bow from the relaxed to the deformed state causes energy to be stored in the composite bow 20. - 5 -

The latching means used to hold the composite bow 20 in the deformed state can be of any suitable form and is connected to a sensor system (not shown) used to determine when a pedestrian impact criteria has been met.

The sensor system may comprise of a microprocessor arranged to receive one or more sensor signals, analyse the received signals and send a signal to the latching means when one or more predetermined pedestrian impact criteria have been met. If a simple impact sensor is used then the criteria used will be actual pedestrian contact with the motor vehicle 10 and in particular with a bumper of the motor vehicle 10. If a forward looking sensor is used then an impact can be predicted from the signals received from the sensor and so the criteria would in this case be that an impact with a pedestrian has been predicted.

In either case when the sensor system determines that the bonnet needs to be raised, a release signal is sent to the latching means and the stored energy within the composite bow 20 is released causing the composite bow 20 to react against the bonnet 15 and raise the bonnet 15 to a desired raised position as shown in Fig.1. It will be appreciated that any locking means holding the bonnet 15 closed will probably need to be released at the same time.

If required one or more restraining arms 16 can be provided between the bonnet 15 and the body structure 11 to limit upward movement of the bonnet 15 and then prevent the bonnet 15 closing when a load is applied in a downwardly direction by the impact of a pedestrian falling upon the bonnet 15.

It will be appreciated that the composite bow 20 is not damaged when it is released and so, in the case of an accidental release, it could be reset to the deformed position without the need to change or replace any significant components. It will be further appreciated that the use of a composite material for the elongate spring member provides a - 6 - spring that can store a considerable amount of energy while being relatively simple to manufacture, is relatively light and will not cause corrosion problems with other components of the motor vehicle 10.

With particular reference to Figs 5a and 5b there is shown a second embodiment of the invention which in some respects is similar to that previously described.

The motor vehicle 110 as before has a body structure 111 defining an engine compartment 112 separated from a passenger compartment of the motor vehicle 110 by a bulkhead 113. A rear hinged bonnet 115 is fastened to the body structure 11 by means of hinges (not shown) near to the rear edge of the bonnet 115 and is held in a closed position near to a front edge of the bonnet 115 by a releasable locking mechanism (not shown).

An elongate spring member in the form of a plastic composite bow 120 is attached to the bonnet 115. As shown in Fig.5a, the composite bow 120 in a relaxed state is, as before, of an arcuate form and is slidingly attached to the bonnet 115 by engagement at each end with a conduit 127 formed by integral parts of the bonnet 115. As shown the conduit 127 is formed by inner and outer panels 124 and 125 of the bonnet 115 and the inner panel 124 has an aperture 126 formed therein to allow the ends of the composite bow to be engaged with the conduits 127. It will be appreciated that other means could be used to attach the composite bow 120 to the bonnet 115 but by using the existing bonnet structure a cost efficient and simple to manufacture assembly is provided.

A latching means 130 is fastened to the inner panel 124 and is used to hold the composite bow 120 in the deformed state.

As can be seen the composite bow extends transversely across the bonnet 115 of the motor vehicle 10, that is to say, it extends from a position near to the left side of the bonnet to a position near to the right side of the bonnet 115. This is useful in that it enables _ 7 _ the composite bow 120 to be packaged in such a way that it does not affect or interfere with the crush performance of the motor vehicle 110.

The composite bow 120 during normal use of the motor vehicle 10 is held in a deformed state by the latching means 130. In the deformed state the composite bow 120 is deformed to a less arcuate form and, in this deformed state, energy is stored in the composite bow 120.

To assemble the composite bow 120 to the bonnet 115 the composite bow 120 in the relaxed state is positioned within the aperture 126 in the inner panel 124 and the inner and outer panels 124 and 125 are then fastened together thereby trapping the ends of the composite bow 120 in the conduits 127. A force is then applied to a central portion of the composite bow 120 to deform it until the latching means can be engaged. The composite bow 120 will remain held in this deformed state until it is required to raise the rear edge of the bonnet 115.

The latching means 130 used to hold the composite bow 120 in the deformed state can be of any suitable form and is connected to a sensor system (not shown) used to determine when a pedestrian impact criteria has been met. The sensor system can be a sensor system as previously described with respect to the first embodiment or can be any other suitable system able to provide a release signal to the latching means 130 when the bonnet 115 needs to be raised.

As before when the sensor system determines that the bonnet needs to be raised, a release signal is sent to the latching means 130 and the stored energy within the composite bow 120 is released causing the composite bow 120 to react against the body structure 111 adjacent to the bonnet 115 and raise the bonnet 115 to a desired raised position which is typically 60 to 70 mm above its normal position. l - 8-

It will be appreciated that, because the bonnet 115 is in this case pivotally connected to the body structure 11 at its rear edge, it is necessary to use a hinged connection between the body structure 11 that not only allows normal opening and closing of the bonnet 115 but also permits the rear of the bonnet 115 to be raised. A suitable hinge for achieving this aim is described in WO-A-01/23226 but other mechanisms could also be used.

In order to allow the rear edge of the bonnet 115 to be raised it may in some cases be necessary to release any locking means holding the front of the bonnet 115 closed at the same time as the latching means is released.

One of the advantages of this embodiment is that the composite bow 120 is attached to the bonnet 115 as part of the bonnet assembly process and that, because the latching means is also fastened to the bonnet 115, the bonnet 115 along with the deformed composite bow 120 form a single assembly which can be fitted directly to the motor vehicle 110. It is only then necessary to connect the latching means 130 to the sensor system to complete assembly and no other fixing of the composite bow 120 to the motor vehicle 110 is required. This provides for a simple and cost effective assembly process.

It will be appreciated by the man skilled in the art that the invention has been described by way of example with reference to two embodiments of the invention but that the invention is not so limited and that various modifications or alternative embodiments to the disclosed embodiments could be made. For example although the invention has been described with reference to the use of a single spring extending across the motor vehicle it would be possible to use more than one spring and to arrange for the spring to located in a different position or orientated differently. -9 -

Claims

1. A safety device for a bonnet of a motor vehicle comprising an elongate spring member to raise a rear edge of the bonnet in the event of a collision with a pedestrian wherein the elongate spring member is held in a deformed state during normal use of the motor vehicle and is released to a relaxed state to raise the rear edge of the bonnet.

2. A safety device as claimed in claim 1 wherein the elongate spring member is made from a plastic composite material.

3. A safety device as claimed in claim 1 or in claim 2 wherein the elongate spring member is of an arcuate form when in the relaxed state.

4. A safety device as claimed in any of claims 1 to 3 wherein the elongate spring member is deformed to a less arcuate form when in the deformed state.

5. A safety device as claimed in any of claims 1 to 4 wherein the elongate member is of a substantially flattened form when in the deformed state.

6. A safety device as claimed in any of claims 1 to 5 wherein the elongate member extends transversely across the motor vehicle to which it is fitted.

7. A safety device as claimed in any of claims 1 to 6 wherein the elongate spring member is attached to part of the body structure of the motor vehicle and reacts against the bonnet to raise the rear edge of the bonnet.

8. A safety device as claimed in claim 7 wherein each of the distal ends of the elongate spring member has a slot formed therein used to slidingly attach the elongate spring member to the body structure of the motor vehicle. - 1 0

9. A safety device as claimed in any of claims 1 to 6 wherein the elongate spring member is attached to the bonnet of the motor vehicle and reacts against part of the body structure of the motor vehicle to raise the rear edge of the bonnet.

10. A safety device as claimed in claim 9 wherein the elongate spring member is engaged at each end with a respective guide formed by inner and outer panel of the bonnet so as to slidingly attach the elongate spring to the bonnet.

11. A safety device as claimed in any of claims 1 to 10 wherein the elongate spring member is held in the deformed state by one or more latching means.

12. A safety device as claimed in claim 11 wherein the or each latching means is connected to a sensor system used to determine a pedestrian impact criterion selected from one of actual impact with a pedestrian and predicted impact with a pedestrian and is released when the pedestrian impact criterion is met.

13. A safety device for a bonnet of a motor vehicle comprising a spring member made from a plastic composite material to raise a rear edge of the bonnet in the event of a collision with a pedestrian wherein the spring member is held in a deformed state during normal use of the motor vehicle and is released to a relaxed state to raise the rear edge of the bonnet.

14. A safety device for a bonnet of a motor vehicle substantially as described herein with reference to the accompanying drawing.