GB2457715A - A hinge mechanism for a vehicle bonnet - Google Patents

Abstract

A hinge mechanism provides a hinged connection between a bonnet 11 and a body structure of a motor vehicle, the hinge mechanism allowing the rear edge of the bonnet to be lifted from a normal position to a deployed position under an upward force so that improved pedestrian safety in the event of a vehicle collision is provided. The mechanism comprises an upper leaf 13 connected to the bonnet, a lower leaf 12 connected to the body structure of the vehicle and a middle leaf 14 connected to the upper leaf 13 and the lower leaf 12. The middle leaf 14 is coupled to the upper leaf 13 by means of a magnetic connector 35 which is adapted to be released only under an upward force exerted by a lift actuator. The magnet, carried by a flange provided on one of the leaf members, may connect to a ferromagnetic part of the hinge mechanism or to a second magnet. The hinge may also be provided with a shear pin.

Description

A hinge mechanism The present invention relates to a hinge mechanism to lift the rear edge of a hood or bonnet of a motor vehicle providing improved pedestrian safety.

Various hinge mechanisms have been proposed to mount the bonnet to a body structure such that, in the event of a detected collision with a pedestrian, the rear edge of the bonnet is raised by means of at least one lift actuator from its normal closed position to a partially raised position. Such hinge mechanisms usually include first and second hinge members which in normal use of the bonnet are fast with each other by a normally fixed but frangible connection. This releasable connection, which takes the form of a shear pin, will be released when sufficient force is applied to it. When this happens it allows the first and second members to move relative to each other so as to allow the rear edge of the bonnet to be lifted in the event of a pedestrian collision, see for example WO 03082638.

It is a problem with such a known shear pin that when the bonnet is closed by slamming it there is a risk that the shear pin might break under the slamming force of the bonnet. In order to avoid this risk it has been proposed to strengthen the shear pin so that the force to break it is increased. Although such a design can overcome the problem, it may have an incidental effect on the deployment time needed to be able to release the releasable connection and then lift the bonnet. In addftion, if the bonnet is raised in response to an impact signal, the bonnet if undamaged or not badly damaged cannot be re-latched unless the releasable connection of the hinges, or the hinges are replaced, causing the bonnet to be moved up and down due to vibration during running of the vehicle.

It is an object of the present invention to provide a mechanism which overcomes or alleviates the above problem.

The present invention relates to a hinge mechanism for providing a hinged connection between a bonnet and a body structure of a motor vehicle, the hinge mechanism allowing the rear edge of the bonnet to be lifted from a normal position to a deployed position under an upward force, the hinge mechanism including first and second hinge members, each hinge member having an elongate vertical side plate carrying a flange, wherein the flanges are coupled to each other by a releasable connection assembly which comprises an engagement element attached to one of the flanges and a connector attached to the other flange, the connector including a magnet.

Preferably the magnet is a rare-earth magnet The magnet may have a release load in the range between 1.5 and 1.8kN.

The connector may comprise a base provided with a central recess therein may be disposed the magnet.

The engagement element may be one of the flange which is made of ferromagnetic material.

In an alternative, the engagement element is a second magnet.

In another alternative, the engagement element comprises a ferrous metal member extending from the corresponding flange of the hinge mechanism.

The hinge members may be further connected to each other by a shear pin.

According to a second aspect of the invention there is provided a motor vehicle having at least one hinge mechanism as described in the first aspect of the invention.

The invention will now be described by way of example with reference to the accompanying drawings of which: -Fig.1 is a schematic view of a hinge mechanism connected to the rear edge of a bonnet in its normal position, Fig.2 is a view similar to Fig.1 but showing the hinge mechanism in its open position, i.e. when the bonnet is opened in the normal way, Fig.3 is a view similar to Fig.1 but showing the hinge mechanism in an extended position in the event of a detected collision with, for instance, a pedestrian, Fig.4 is a plan view of a releasable connection assembly according to the present invention.

With reference to Figs.1 to 4, there is shown a hinge mechanism 10 intended to pivotally connect a rear edge of a bonnet 11 to a vehicle body structure (not shown). It will be noted that the bonnet 11 is pivotally attached to the body structure in a conventional manner by two hinge mechanisms 10 (only one shown) each located towards respective right and left hand sides of the bonnet 11.

Each hinge mechanism 10 is associated with a lift actuator (not shown). Each hinge mechanism 10 comprises, in this example, three leaves or hinge members, a lower leaf or hinge member 12 attached to part of the body structure, an upper leaf or hinge member 13 attached to the bonnet 11 and a middle leaf or hinge member 14 connected to the lower and upper leaves 12, 13. Each leave is made of ferromagnetic material, i.e. steel.

The lower leaf 12 has, at its rearward end, an upwardly extending portion 15 which is pivotally attached at a pivot axis 9 to the rearward end of the middle leaf 14. At its free end the middle leaf 14 has a laterally extending stud 16.

The upper leaf 13 has at its forward end an elongate slot 17. The stud 16 extends through the slot 17 and is slideable along the slot 17.

A guide link 18 is pivotally connected in a known manner at one 20 of its ends to the middle leaf 14 and at its other end 19 to the upper leaf 13.

The upper leaf 13 has a generally elongate vertical side plate 1 3a carrying an inwardly directed mounting flange from its uppermost edge. The inwardly directed flange has a pair of mounting apertures formed therethrough to allow the upper leaf 13 to be securely mounted, for example by a pair of bolts, to the bonnet 11. The middle leaf 14 has, similarly to the upper leaf 13, a generally elongate vertical side plate carrying an inwardly directed connecting flange from its uppermost edge.

The upper leaf 13 is coupled to the middle leaf 14 by a releasable connection assembly 30.

As can best be seen in Fig.4, the releasable connection assembly 30 includes a base 31, that is cuboid-shaped, having a lower and an upper surfaces 32 and 33. The lower surface 32 of the base 31 is attached to inwardly flange of the middle leaf 14. A central recess 34 is formed in the upper surface 33. A connector 35 in the form of a magnet is fixedly disposed in the central recess 34. The magnet 35 is preferably a rare earth magnet, for example, a neodymium-based permanent magnet. It will be appreciated that the assembly 30 could be inverted. i.e. that the base is attached to the inwardly flange of the upper leaf 13.

The inwardly directed flange of the upper leaf 13, which is made of ferromagnetic material, acts as an engagement element and thus is attracted to the magnetic connector 35.

During normal operation of the hinge mechanism 10, the bonnet 11 is articulated around the pivot axis 9 between the lower leaf 12 and the middle leaf 14, the upper leaf 13 being prevented from pivoting with respect to the middle leaf 14 about the stud 16 by the magnetic connector 35.

When the lift actuators begin to deploy, the upward force exerted by the lift actuators on the bonnet 11 is greater than the release load of the magnetic connector 35 which in this example is in the range between 1.5 and 1.8kN. Hence, the lift actuators are able to release the upper leaf 13 from the middle leaf 14 so that the upper and middle leave 13, 14 are free to pivot with respect to one another about the stub 16. The hinge mechanism can then open out into an extended or deployed position as the rear end of the bonnet is lifted by the deployment of the lift actuator.

Then the bonnet 11 can be pushed down to its normal position where the magnetic connector 35 of each hinge mechanism will hold the upper leaf 13 to the middle leaf 14 and the lift actuators be retracted.

The magnetic connector 35 described here allows the hinge assemblies to be reset in the event of minor damage to the bonnet 11 after impact so that the vehicle can be driven to a garage for replacement of the lift actuators. As the magnetic connector is still operational there are no vibration noises which can be annoying for the driver when the car is driven away.

In an alternative, the engagement element of the magnetic connector is a ferrous metal member extending from the upper leaf when the connector is attached to the middle leaf and located in register of the magnetic connector in normal position of the hinge mechanism.

In another modification, the engagement element is another magnet attached to the upper leaf in the same way as the magnetic connector.

It will be appreciated that at least one hinge mechanism can also have a shear pin to retain the upper leaf to the middle leaf.

Claims (10)

1. CLAIMS1. A hinge mechanism for providing a hinged connection between a bonnet and a body structure of a motor vehicle, the hinge mechanism allowing the rear edge of the bonnet to be lifted from a normal position to a deployed position under an upward force, the hinge mechanism including first and second hinge members, each hinge member having an elongate vertical side plate carrying a flange, wherein the flanges are coupled to each other by a releasable connection assembly which comprises an engagement element attached to one of the flanges and a connector attached to the other flange, the connector including a magnet.
2. 2. A hinge as claimed in claim 1 in which the magnet is a rare-earth magnet.
3. 3. A hinge as claimed in claim 2 in which the magnet has a release load in the range between 1.5 and 1.8kN.
4. 4. A hinge as claimed in any one of claim 1 to 3 in which the connector comprises a base provided with a central recess therein is disposed the magnet.
5. 5. A hinge as claimed in any one of claim 1 to 4 in which the engagement element is one of the flange which is made of ferromagnetic material.
6. 6. A hinge as claimed in any one of claim 1 to 4 in which the engagement element is a second magnet.
7. 7. A hinge as claimed in any one of claim 1 to 4 in which the engagement element comprises a ferrous metal member extending from the corresponding flange of the hinge mechanism.
8. 8. A hinge as claimed in any one of claim 1 to 7 in which the hinge members are further connected to each other by a shear pin.
9. 9. A motor vehicle having at least one hinge mechanism according to any preceding claim.
10. 10. A hinge mechanism arranged substantially as described herein with reference to Figs 1 to 4 of the accompanying drawings.