GB2452252A

GB2452252A - A hinge mechanism capable of lifting the rear edge of a bonnet

Info

Publication number: GB2452252A
Application number: GB0716364A
Authority: GB
Inventors: Nikolaos Kalargeros
Original assignee: Jaguar Cars Ltd; Ford Global Technologies LLC
Current assignee: Jaguar Land Rover Ltd; Ford Global Technologies LLC
Priority date: 2007-08-23
Filing date: 2007-08-23
Publication date: 2009-03-04
Anticipated expiration: 2027-08-23
Also published as: GB0716364D0; GB2452252B

Abstract

A hinge mechanism (10) to lift the rear edge of a bonnet (11) of a motor vehicle has an upper leaf (13) connected to the bonnet (11), 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 a tensile pin which is adapted to be broken or distorted only under an upward force exerted by a lift actuator so as to lift the bonnet from a normal position to a deployed position.

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.

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

According to a first aspect of the invention there is provided 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 including a frangible member which has an axis substantially perpendicular to the flanges.

Preferably, the frangible member is a tensile pin which is adapted to be broken by tensile stresses applied to the hinge mechanism. Such a tensile pin is adapted to break along a line that is, in use, parallel to the flanges.

In an alternative, the frangible member is adapted to be distorted by tensile stresses applied to the hinge mechanism. Preferably, the frangible member is a deformable locking element such as a spacer provided with a head having an outer frusto-conical surface.

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 a pedestrian, Fig.4 is a perspective side view in the direction of arrow "A" in Fig.1 but to a larger scale showing part of a releasable connection assembly seen in Fig. 1, Fig.5 is a cross-section through part of the hinge mechanism showing the releasable connection assembly of Fig. 4 to a larger scale, and Fig.6 is view similar to Fig.5 but showing an alternative 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 steel 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.

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

To reduce the risk that the force created when the user slams the bonnet 11 in order to close it may release the releasable connection assembly, the releasable connection assembly arranged between the upper leaf 13 and the middle leaf 14 is provided with a frangible member 21 adapted to be broken only under a tensile force.

To do so, as seen in Fig. 4, the upper leaf 13 has a generally elongate vertical side plate 13a carrying an inwardly directed mounting flange 13b from its uppermost edge. The inwardly directed flange 13b has a pair of mounting apertures 13c 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 14a carrying an inwardly directed connecting flange 14b from its uppermost edge. The inwardly directed flange 14b has a connecting aperture 14c therethrough. A corresponding connecting aperture 13d is also formed in the flange 13b of the upper leaf 13 to allow the upper leaf 13 to be releasably attached to the middle leaf 14 by the releasable connection assembly 30 having a frangible member 21, in this example a 1 5 tensile pin.

Referring now in particular to Fig. 5, the releasable connection assembly 30 includes an elongated locking pin bolt 21 (forming the frangible member) with an axis substantially perpendicular to the flanges 13b, 14b, a washer 22, a spacer 23 and a nut 24. The locking pin bolt 21 has an enlarged head 25 at its uppermost end and a circular groove 26 forming a weakness area, substantially parallel to the bonnet 11 and the flanges 1 3b, 1 4b, more prone to break under a tension force as it will be explained further in detail thereafter.

The locking pin bolt 21 is placed within the apertures 13d, 14c of the upper and middle leaves 13, 14, such that the locking pin bolt 21 of the releasable connection assembly 30, extends in order through the washer 22, the apertures 13d, 14c, the spacer 23 and lastly into the nut 24 into which the locking pin bolt 21 is threadably fastened.

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 releasable connecting assembly 30.

When the user close the bonnet 11 by slamming it there is no risk that the pin bolt 21 of the releasable connection assembly 30 fails as the compression force created at the moment of the slam of the bonnet, will not be transferred to the pin bolt 21 thanks to an abutment (not shown) between the hinge members or in an alternative an abutment between the upper flange and one end of the spacer. Hence only the tension force exerted by the lifts actuators will break the pin bolt of each hinge mechanism as explained below.

When the lift actuators begin to deploy, the upward force exerted by the lift actuators on the bonnet 11 is sufficient to create a tension force causing tensile stresses on the elongated pin bolt 21. These tensile stresses are enough to break the pin bolt 21 about the groove 26 releasing 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.

In an alternative shown in Fig.6, the frangible member of the releasable connection assembly is replaced by a deformable spacer 41. Hence, the releasable connection assembly 40 includes an elongated pin bolt 42, a washer 43, the deformable spacer 41 and a nut 44. The pin bolt 41 has an enlarged head 45 at its uppermost end. The deformable spacer 41 has at its lowermost end a head 46 having an outer frusto-conical surface which tapers towards the lowermost end of the washer. The deformable spacer 41 is made of a plastic material.

The pin bolt 42 is placed within the apertures 1 3d, 1 4c of the upper and middle leaves 13, 14, such that the pin bolt 42 of the releasable connection assembly 40 extends in order through the washer 43, the apertures 1 3d, 1 4c, the deformable spacer 42 and lastly into the nut 44 into which the pin bolt 41 is threadably fastened.

When the lift actuators begin to deploy, the upward force exerted by the lift actuators on the bonnet 11 is sufficient to distort the head 46 of the spacer 41 and then release the upper leaf 13 from the middle leaf 14 so that the upper and middle leave 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. Such a deformable spacer 41 ensures that the releasable connection will resist any compressive effort as no force is transmitted to the head 46 of the spacer when a compressing effort is exerted. Only a tension force is able to release the upper leaf from the middle leaf.

Although the invention has been described by way of example with reference to a specific hinge mechanism, the frangible or deformable member can be applied to other hinge mechanism.

Furthermore, other modifications may be made without departing from the invention.

For instance, the middle leaf 14 may not be provided with a connecting aperture but with a recess aligned to the connecting aperture of the upper hinge and the deformable spacer adapted to hook the edge of this recess. Hence under an upward force exerted by the lift actuators the spacer is distorted and thus the upper and middle hinge members are released from each other.

Claims

1. 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 including a frangible member which has an axis substantially perpendicular to the flanges.

2. A hinge as claimed in claim 1 in which the frangible member is adapted to be broken by tensile stresses applied to the hinge mechanism.

3. A hinge as claimed in claim 2 in which the frangible member is a tensile pin.

4. A hinge as claimed in claim 3 in which the frangible member is adapted to break along a line that is parallel to the flanges.

5. A hinge as claimed in claim 4, each flange having a connecting aperture therethrough and wherein the releasable connection assembly further includes a nut, the frangible member having a head and being placed within the connecting apertures of the first and second hinge members, such that the frangible member extends through the apertures and into the nut into which the frangible member is threadably fastened.

6. A hinge as claimed in claim 1 in which the frangible member is adapted to be distorted by tensile stresses applied to the hinge mechanism.

7. A hinge as claimed in claim 6 in which the frangible member is a deformable locking element.

8. A hinge as claimed in claim 7 wherein the deformable locking element is a spacer provided with a head having an outer frusto-conical surface.

9. A hinge as claimed in claim 8, each flange having a connecting aperture therethrough and wherein the frangible releasable connection assembly further includes an elongated pin bolt having a head and a nut, the pin bolt being placed within the connecting apertures of the first and second hinge members, such that the pin bolt extends through the apertures, the deformable spacer and lastly into the nut.

10. A motor vehicle having at least one hinge mechanism according to any preceding claim.

11. A hinge mechanism arranged substantially as described herein with reference to Figs 1 to 5, or Fig. 6 of the accompanying drawings.