EP2162315A1

EP2162315A1 - A haptic alert system for a motor vehicle

Info

Publication number: EP2162315A1
Application number: EP08767261A
Authority: EP
Inventors: Lennart Simonsson; Jan-Erik KÄLLHAMMER
Original assignee: Autoliv Development AB
Current assignee: Autoliv Development AB
Priority date: 2007-07-02
Filing date: 2008-06-27
Publication date: 2010-03-17
Also published as: EP2162315A4; WO2009005463A1; EP2162314A1; WO2009005414A1; EP2162314A4

Abstract

A haptic alert system is disclosed which is arranged to impart a vibratory motion to the back rest of a vehicle seat. The mechanism supports the back of a seat in a motor vehicle and comprises at least one first component (2,3) which is adapted to be connected to the squab of a seat, and at least one further component (32) which is adapted to be connected to the back of the seat. The components (2,3,32) are connected together by a connection arrangement. The connection arrangement is configured to permit the further component (32) to pivot relative to the first component (2,3) and an actuator arrangement (53) is provided which is configured to move the further component (32) pivotally relative to the first component (2,3) in an oscillating manner in order to impart a vibrating alert to the back rest.

Description

¹A HAPTIC ALERT SYSTEM FOR A MOTOR VEHICLE"

Description

THE PRESENT INVENTION relates to a haptic alert system for a motor vehicle, and more particularly to such a system including a seat back support mechanism for supporting the back of a seat in a motor vehicle.

It has been proposed previously to provide motor vehicles with safety systems designed to provide feedback to the driver (and possibly also other passengers) regarding the status of the vehicle and certain driving parameters in a haptic manner, i.e. through the sensation of touch. Such systems provide haptic alerts to the driver of a vehicle by a series of vibrations through the driver's seat, in response to signals indicative of events such as the car crossing a lane of the road, the driver becoming drowsy or oncoming vehicles etc.

Previously proposed safety devices of this sort typically provide a haptic seat which incorporates a mechanism to impart a vibratory motion to part or all of the seat squab. A typical mechanism for this purpose comprises one or more rotary driven eccentric weights.

However, it has been found that systems arranged to impart a vibratory motion to the squab of the vehicle seat can add significantly to the overall complexity, weight and cost of the seat, and can also often be difficult to retro-fit to existing seats by way of an upgrade.

Also, when a vehicle with a conventional seat, or indeed a vehicle with a haptic seat of the general type mentioned above, is involved in a rear impact, the seat may be accelerated with a substantial forward acceleration since the seat is secured to the floor of the vehicle. The posterior and torso of an occupant of the vehicle sitting on the seat will consequently be accelerated, because of the intimate contact between the seat, and the back of the seat, and the posterior and torso of the occupant. The head of the occupant, however, is not in direct contact with the seat and, due to its inertia, will tend to remain stationary. Since the posterior and torso are being accelerated forwardly, this means that effectively the head of the occupant may move rearwardly relative to the torso, thus bending the neck of the occupant. This can cause injury to the occupant.

It is now believed that the risk of injury to an occupant of a vehicle can be diminished if the back of the seat is mounted in such a way that the top part of the seat back can move forwardly to support the head of the occupant and also in such a way that the seat back can subsequently "yield", at least to a predetermined extent, during a rear impact. In this way, the torso of the occupant can be caused to accelerate in a more gradual manner, and the head of the occupant can be supported thus reducing the risk of injury.

A prior proposed seat back support mechanism of the type described above is disclosed in GB-A-2316442. This prior proposed seat back support mechanism incorporates a pivot link arrangement which is configured to permit the lower part of a seat back to be displaced rearwardly. The pivot link arrangement is locked normally by a frangible pin. The frangible pin is configured to break to allow the pivot link arrangement to displace the lower part of the seat back when the lower part of the seat back is subjected to a force by a seat occupant which is in excess of a predetermined threshold. As the lower part of the seat back moves rearwardly the upper part of the seat back moves forwardly to a position which is closer to the head of the seat occupant to offer support to the head of the seat occupant. After the lower part of the seat back has been displaced the mechanism is configured to pivot rearwardly under the influence of forces exerted by the seat occupant on the seat back whilst absorbing energy from the seat occupant.

After the mechanism has been actuated the frangible pin must be replaced before the seat back can be returned and locked in its normal position. A problem with this prior proposed mechanism is that the frangible pin can become deformed and broken by forces other than the forces exerted by the seat occupant in a rear impact, such as forces arising from cargo or a rear seat passenger striking the rear of the seat back during a frontal impact. Forces exerted on the rear of the seat back during a frontal impact may cause the frangible pin to become deformed or to break unnecessarily. The frangible pin must then be replaced to return and lock the seat back in its normal position and the replacement can be expensive and time consuming.

The present invention seeks to provide an improved haptic alert system for a motor vehicle.

According to a first aspect of the present invention, there is provided a haptic alert system for a motor vehicle, the system comprising a seat back support mechanism for supporting the back of a seat in a motor vehicle, the seat back support mechanism having; at least one first component adapted to be connected to the squab of the seat or to a frame supporting the squab of the seat; at least one further component adapted to be connected to the back of the seat, the further component being connected to the first component by a connection arrangement configured to permit the further component to move relative to the first component; the system further comprising an actuator arrangement configured to move the further component relative to the first component in an oscillating manner.

Preferably the connection arrangement is configured to permit the further component to pivot relative to the first component. Advantageously, the actuator arrangement is configured to move the further component pivotally relative to the first component in said oscillating manner.

Preferably the actuator arrangement comprises at least one alert sensor configured to generate an actuating signal in response to the occurrence of an event or driving parameter requiring the seat-occupant's attention.

Conveniently, the further component is provided with an elongate guide slot the guide slot receiving slideably a guide member, the further component being configured to move relative to the guide member when the further component moves relative to the first component.

Advantageously the length of the guide slot is from 10 to 40 mm.

Preferably the actuator arrangement comprises a Bowden cable which has an outer sheath fixed relative to the further component and an inner cable fixed relative to the guide member such that sliding movement of the inner cable within the outer sheath is effective to move the further component relative to the guide member.

Advantageously, the actuator arrangement comprises an electric motor configured to move said inner cable within said outer sheath in an oscillating manner in response to said actuating signal.

Conveniently, the connection arrangement of the seat back support mechanism further comprises a deformable element configured to resist displacement of the further component relative to the first component, the deformable component being configured to deform in the event that a force in excess of a predetermined level is exerted on the further component to permit displacement of the further component relative to the first component, wherein the connection arrangement is configured to permit said oscillating movement of the further component relative to the first component, without deforming the deformable element.

Preferably, the connection arrangement is configured to permit the further component to pivot relative to the first component from a first orientation to a second orientation in response to fulfilment of a first criterion without deforming the deformable element; wherein the seat back support mechanism further comprises return means which is configured to act on the further component to return the further component from the second orientation to the first orientation in response to fulfilment of a second criterion.

Advantagoeusly, the guide member is positioned at a first position along the length of the guide slot when the further component is in the first orientation and the guide member is positioned at a second position along the length of the guide slot when the further component is in the second orientation.

Conveniently, said oscillating pivotal movement of the further component relative to the first component occurs about the same pivot point as the movement in response to fulfilment of said first criterion.

Preferably, the actuator arrangement is configured such that said oscillating pivotal movement occurs over a range which is less than the full range of movement between said first and second orientations.

Advantageously, the connection arrangement further comprises a blocking element which blocks movement of the further component relative to the guide member, the blocking element being releasable in response to fulfilment of the first criterion to permit movement of the further component relative to the guide member.

Conveniently, the first criterion is a force exerted on the further component which is in excess of a predetermined level.

Preferably, the second criterion is a force exerted on the return means which is in excess of a predetermined level.

Avantageously, the return means comprises said Bowden cable such that the inner cable moves the further component relative to the guide member when a force in excess of a predetermined level is exerted on one end of the inner cable.

Conveniently, the connection arrangement further comprises a biasing element which biases the further component towards the first orientation.

Preferably the biasing element is a spring.

Advantageously, the deformable element is a frangible release element.

Conveniently, the deformable element is a spring.

Preferably, the further component comprises a recliner support plate which supports a recliner mechanism.

According to another aspect of the present invention, there is provided a vehicle seat provided with a haptic alert system of the type defined above.

In order that the invention may be more readily understood, and so that further features thereof may be appreciated, embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a seat back support mechanism forming part of the preferred embodiment of the invention, Figure 2 is an exploded view of the seat back support mechanism of figure 1 ,

Figure 3 is a plan view of four co-operating parts of a movement arrangement which forms part of the mechanism shown in figures 1 and 2 in a first condition,

Figure 4 is a view corresponding to figure 3 showing the four parts in a second condition,

Figure 5 is a view corresponding to figures 3 and 4 showing the four parts in a third and final condition,

Figure 6 is a plan view of parts of a pivoting arrangement which forms part of the mechanism shown in figures 1 and 2 in an un-actuated condition,

Figure 7 is a view corresponding to figure 6 with the parts of the pivoting arrangement in an actuated condition,

Figure 8 is a plan view of part of the pivoting arrangement shown in figures 6 and 7 with a return mechanism in an un-actuated condition,

Figure 9 is a view corresponding to figure 8 with the return mechanism in an actuated condition,

Figure 10 is a view corresponding to figure 6 following actuation of the pivoting arrangement and the movement arrangement,

Figure 11 is a view similar to that of figure 8, showing the arrangement at one position during an oscillating mode of operation;

Figure 12 is a view corresponding to that of figure 11 , showing an alternate position during said oscillating mode of operation;

Figure 13 is a view corresponding to that of figure 3, but illustrating an alternative embodiment;

Figure 14 is a view corresponding to that of figure 4, illustrating the embodiment of figure 13, and

Figure 15 is a view corresponding generally to that of figure 5, illustrating the embodiment of figures 13 and 14.

Referring initially to figures 1 and 2 of the accompanying drawings, a seat back support mechanism 1 is adapted to be mounted between the squab of the seat, or a frame supporting the squab of the seat, which is connected to the floor of the motor vehicle, and the back of the seat. The mechanism forms part of the haptic system of the present invention, and is additionally adapted to provide a "recliner" effect, whilst also being provided with means which can be actuated to permit the back of the seat to be tilted forwardly, which may prove convenient if, for example, the seat is the front seat in a two-door motor car, in order to provide access to the rear seats of the car.

As will be described, the support mechanism 1 includes a movement arrangement which, when actuated, allows the back of the seat to be displaced to effect a first movement relative to the squab of the seat, if the force applied to the back of the seat exceeds a certain limit, in which the lower part of the back of the seat moves rearwardly and the top part of the back of the seat moves forwardly. Subsequently the back of the seat may effect a second movement, if the force applied to the back of the seat is in excess of a predetermined threshold, during which the back of the seat effectively tilts rearwardly, with the bottom part of the back of the seat remaining substantially stationary and the top part of the back of the seat moving rearwardly. As will be described below, the seat back support mechanism 1 also includes a connection arrangement which permits the back of the seat to pivot forwardly without necessarily displacing the lower part of the back of the seat. Both of these pivoting functions are provided in addition to the oscillatory haptic alert function of the seat.

Considering the components that together constitute the mechanism 1 as illustrated in figures 1 and 2, it is to be understood that the mechanism comprises a front main support plate 2 of substantially triangular form, and a rear main support plate 3 of a substantially corresponding form, the plates 2 and 3 forming the outer parts of the mechanism, the remaining components being located at least partly between the outer plates 2 and 3.

The front main support plate 2 is provided with a first aperture 4 co-aligned with a corresponding first aperture 5 formed in the rear main support plate 3. A bearing 6 passes through these apertures and pivotally supports two intermediate components as will be described hereinafter.

The front main support plate 2 defines a further aperture 7 which is co-aligned with a corresponding further aperture 8 formed in the rear main support plate 3. A bolt 9 is provided which passes through the co-aligned apertures 7 and 8, the bolt 9 being associated with a nut 10 located adjacent the rear main support plate 3. One intermediate element is pivotally mounted on a bearing surface provided on the bolt 9, as will be described hereinafter.

The front main support plate 2 defines two further apertures 11 , and the rear main support plate defines two further co-aligned apertures 12. Each pair of apertures 11 ,12 receives a respective spacer element 13,14, the spacer elements being located between the front and rear main support plates. The front and rear main support plates 2,3 are provided with means to mount the described mechanism in position on the squab of a vehicle seat or on a frame which supports the squab of a vehicle seat.

The bearing 6 pivotally supports an intermediate support plate 15. The intermediate support plate 15 defines a first aperture 16 which receives the bearing 6. The intermediate support plate 15 can thus pivot about an axis defined by the aperture 16 and the bearing 6. The lower part of the intermediate support plate defines a recess 17. A locking lever 18 is provided having a forward end 19 which has an exterior profile corresponding to the profile of the recess 17. The locking lever 18 has formed therein an aperture 20 which is located between the forward end 19 and a protruding handle portion. The aperture 20 of the locking lever 18 receives the bearing on the bolt 9 so the locking lever 18 is pivotally mounted for pivotal rotation about the axis defined by the bolt 9. The locking lever 18 is mounted in a position which is co-planar with the intermediate support plate 15. The locking lever 18 may move from a first position, in which the forward end 19 of the locking lever is snugly received within the recess 17, thus preventing rotation of the intermediate support plate 15 in either sense about the axis defined by the bearing 6 and the aperture 16, and a release position, in which the forward end 19 of the locking lever 18 is disengaged from the recess, thus permitting the intermediate support plate 15 to pivot in a forward direction (i.e. a counter clockwise direction as viewed in figures 1 and 2) about the axis defined by the bearing 6 and the aperture 16. This movement can be effected when it is desired to tilt the back of the seat forwardly, for example to gain access to the rear seats of a two-door car.

The intermediate support plate 15 defines a substantially triangular guide aperture 21 , the function of which will become clear from the following description.

The intermediate guide plate 15 defines an aperture 22 which receives part of a release element 23, the function of which will become clear from the following description.

The intermediate support plate 15 defines a further aperture 24 which receives a pivot pin 25 which is also received in an aperture 26 formed in one end of an elongate pivot link 27. The link 27 is thus mounted for pivotal movement about an axis defined by the pivot pin 25.

The pivot link 27 is of elongate form. At the centre of the pivot link 27 is an aperture 28. In an initial position of the pivot link, the aperture 28 in the link 27 is co-aligned with the aperture 22 in the intermediate support plate 15. The deformable release element 23 which is engaged with the aperture 22 has a small extending frangible stud which is located in the aperture 28. The stud thus serves to maintain the pivot link 27 in its initial position. The pivot link 27 defines, at the end remote from the aperture 26, a further aperture 29, that further aperture 29 receiving a further pivot pin 30. The pivot pin 30 is received in an aperture 31 formed in a recliner support plate 32. The recliner support plate 32 will be described in greater detail hereinafter.

A second pivot link 33 is provided which effectively co-operates with the first pivot link 27 to provide a parallel linkage between the intermediate support plate 15 and the recliner support plate 32. The second pivot link 33 is of arcuate form having a first aperture 34 at one end, which receives the bearing 6, and having a second aperture 35 at the other end, which receives a guide member in the form of a pivot pin 36, the pivot pin 36 also being received in an elongate guide slot 37 provided in the recliner support plate 32. The length of the guide slot 37 is preferably from 10 to 40 mm, although it should be appreciated that a longer, or generally larger slot may be provided depending upon the nature of the seat. It is to be noted, however, that part of the pivot pin 36 extends to the other side of the second pivot link 33 and is received within the triangular guide aperture 21 formed in the intermediate support plate 15. A return means 46 is mounted to the recliner support plate 32. In this preferred embodiment, the return means 46 comprises a blocking element 47 in the form of a pin which is connected to a Bowden cable 48. The Bowden cable 48 comprises an inner cable 49 and an outer sheath 50. The blocking element 47 is connected to one end of the inner cable 49 of the Bowden cable 48 and the corresponding end of the outer sheath 50 is fixed to the recliner support plate 32 by a fixture 51. A coil spring 52 is fitted around the blocking element 47 and the coil spring biases the pivot pin 36 and the fixture 51 away from one another, to bias the recliner support plate 32 towards its normal orientation, as seen in figure 6. However, alternative arrangements may not use a Bowden cable arrangement and could, for example, instead use a pneumatically or motor-driven return means.

In order to provide the oscillating haptic function of the present invention, in a manner to be described in further detail below, the Bowden cable is mechanically connected to an actuating arrangement 53. In the embodiment illustrated, the actuating arrangement 53 comprises an electric motor 54 which is mechanically connected to the Bowden cable in a manner effective to move the inner cable 49 to and fro, in a sliding manner, within the outer sheath 50. The motor is electrically connected, via wires 56, to a sensor 55 which is configured to generate an actuating signal in response to the occurrence of an event or driving parameter requiring the seat-occupant's attention. In this context, it is envisaged that the actuating arrangement 53 might only be provided on the Bowden cable of the driver's seat, with the sensor being configured to generate an actuating signal in response to the vehicle changing lane, the driver becoming drowsy, or another oncoming vehicle.

As will become clear from the description below, the blocking element 47 is positioned normally so as to resist movement of the support plate 32 relative to the pivot pin 36. The Bowden cable 48 manages the blocking element 47 and the bias provided by the spring 52 to control their combined blocking and biasing effects to prevent or allow movement of the recliner support plate 32 relative to the pivot pin 36. The function of the return mechanism 46 will be described in further detail below.

The second pivot link 33 is of arcuate form. A "V" notch or recess 38 is provided substantially at the mid point of the link on the interior side of the arc.

The recliner support plate 32 defines an aperture 39 that is provided, about its periphery, with a plurality of inwardly directed teeth 40. The aperture thus effectively forms the ring gear for a planetary gear system. The planetary gear system is mounted between two carrier plates 41 ,42. The carrier plate 42 is formed integrally with a support arm 43 that is adapted to be connected to the frame forming the back of a seat.

It is to be appreciated that a seat back support mechanism, as described with reference to figures 1 and 2, will be provided on each side of the seat, the support arms 43 engaging two arms of an inverted "U"-shaped frame that forms an essential component of the back of the seat.

It is to be appreciated that the planetary gear mechanism comprising the aperture 39, the carrier plates 41 and 42 and the associated co-operating gears may be provided with an adjusting knob, to enable the degree of inclination of the back of the seat to be adjusted, and is conventional.

It will now be understood more clearly that when the locking lever 18 is moved, by actuating the handle, to a position in which the forward end 19 is disengaged from the recess 17, the intermediate plate 15 can be tilted forwardly, effecting a pivotal motion about the axis defined by the bearing 6. The pivot link 27 is locked to the intermediate plate 15 by the release element 23 and consequently, when the lock lever is disengaged from the intermediate support plate 15, the back of the seat may be tilted forwardly.

Referring now to figures 3 to 5, which illustrate the relative position of the intermediate support plate 15, the first pivot link 27 and the second pivot link 33 together with the position of the recliner support plate 32. These four components together effect a predetermined movement when a vehicle in which the seat back support mechanism is provided is involved in a rear impact.

Figure 3 illustrates the four components of interest, when in an initial condition. It is to be observed that the pivot pin 36, at the lower end of the second pivot link 33, is located at a forward position within the generally triangular aperture 21 formed in the intermediate support plate 15. The recliner support plate 32 is in such an orientation that the back of the seat (with the particular adjustment of the recliner mechanism illustrated) is vertical, as indicated by the line 45.

If the vehicle is subjected to a rear impact, a substantial rearwardly directed force is applied to the back of the seat. This initially causes the pivot links 27,33, to commence a rearward pivoting motion. The rearward pivoting motion of the links is only permitted to proceed if the force applied to the back of the seat is sufficiently large to deform and break the frangible part of the release element 23 that is received within the aperture 28 of the first link 27. Thus, if the rear impact is only a very gentle rear impact, the seat remains in its initial condition. However, if the impact is of a predetermined severity, the frangible part will break, thus permitting the pivot links to move. The pivot links then move to the condition illustrated in figure 4.

It is to be observed that the pivot pin 36, provided at the lower end of the pivot link 33, has now moved to a rearward position at the bottom of the generally triangular aperture 21 formed in the intermediate support plate 15. The first pivot link 27 has effected a rearward swinging motion about the axis defined by the pivot pin 25 which is received in the aperture 24 of the intermediate support plate 15 and the aperture 26 of the pivot link 27.

As a consequence the recliner support plate 32 has displaced rearwardly, and the inclination of the recliner support plate 32 has changed so that the seat back is now inclined slightly forwardly, as can be seen from the orientation of the line 45 in figure 4.

It is to be understood that during this movement of the back of the seat, the lower part of the torso of the occupant has effectively engaged the lower part of the back of the seat and moved the lower part of the back of the seat rearwardly. Consequently, the top of the back of the seat is moved forwardly and either the top of the back of the seat or a head-rest carried by the top of the back of the seat will be brought into engagement with the head of the occupant to support the head of the occupant.

Should a continuing rearward force be applied to the back of the seat, that force will tend to pivot the recliner support plate 32 about the axis of the pivot pin 30 which is provided at the lower end of the pivot link 27. This movement with a pivotal action is initially resisted by the second pivot link 33. However, because the second pivot link 33 is of arcuate form, and especially because of the provision of the "V" notch 38 on the inner surface of the arc, the second pivot link 33 can only withstand a predetermined force tending to compress that pivot link. If the force applied to the back of the seat is beyond a predetermined threshold, the second pivot link 33 will collapse and deform, permitting the recliner support plate 32 to pivot about the axis defined by the pivot pin 30.

It is to be understood that the predetermined threshold for the force that must be applied to the back of the seat to cause the second pivot link to collapse is greater than the force necessary to be applied to the back of the seat to cause the frangible part of the release element 23 to break, thus permitting movement of the first pivot link 27. The pivot pin 36 provided at the lower end of the second pivot link 33 thus moves upwardly, within the triangular aperture 21 formed in the intermediate support plate 15, to occupy a position adjacent the upper-most corner of that triangular aperture. As can be seen in figure 5, the second pivot link 33 has collapsed, but it is to be understood that in collapsing, the second pivot link has absorbed energy.

In an alternative embodiment, an additional element may absorb the energy. This element may comprise a spring or other flexible element. In such a case forward movement of the back of the seat after impact has to be prevented. It is to be appreciated also that during the first movement of the back of the seat, an energy absorbing element can be used to absorb energy.

It is to be appreciated that whilst, in the described embodiment, an intermediate support plate 15 is provided, the only real function of the intermediate support plate 15 is to permit a forward-tilting of the entire back of the seat. If a seat back support mechanism is to be provided in a seat which is not present in a two-door car, then the intermediate support plate could be omitted. In such a case, the apertures 21 , 22 and 24 could be formed in the rear main support plate 3. The locking lever 18 would also be omitted.

The connection arrangement which permits the back of the seat to pivot forwardly will now be described. In the preferred embodiment of the invention the connection arrangement comprises the support plates 2,3, the recliner support plate 32, the pivot pin 36, the guide slot 37 and the return means 46. The way that these components co-operate will now be described with reference to figures 6 to 10 of the accompanying drawings.

When the seat back is in its normal, upright, position the recliner support plate 32 is positioned so that the pivot pin 36 sits at the lower end of the guide slot 37, as seen in figure 6. The blocking element 47 and the spring 52 of the return means 46 act to retain the recliner support plate 32 in the normal position relative to the pivot pin 36 so that the seat back remains upright during normal vehicle operation. The blocking element 47 and the spring 52 hold the recliner support plate 32 yieldably so that if a force in excess of a predetermined level is exerted on the recliner support plate 32 then the spring 52 yields to allow the recliner support plate 32 to pivot about the pivot pin 30. The biasing force exerted by the spring 52 in this preferred embodiment represents a first criterion. It is to be appreciated that the first criterion may be fulfilled if a force is exerted on the recliner support plate 32 which overcomes the biasing force exerted by the spring 52. The connection arrangement permits the recliner support plate 32 to pivot relative to the support plates 2,3 in response to this first criterion being fulfilled. The force exerted on the rear of the seat back might, for instance, result from cargo in the rear of the vehicle or a rear passenger striking the seat back during a frontal impact. As the seat back pivots forwardly the recliner support plate 32 pivots about pivot pin 30 and moves such that the pivot pin 36 is positioned at the upper end of the guide slot 37, as shown in figure 7.

As the recliner support plate 32 moves relative to the pivot pin 36, the blocking element 47 pushes one end of the inner cable 49 back into the outer sheath 50 of the Bowden cable 48 which results in the other end of the inner cable 49 moving outwardly from the outer sheath 50 as shown generally by the arrow P in figure 8. In this context, it should be appreciated that in the absence of an actuating signal from the sensor 55, the motor 54 is free to rotate as the inner cable 49 moves relative to the outer sheath 50 in this manner, the motor this offering no effective resistance to this movement. The recliner support plate 32 moves until the pivot pin 36 is positioned at the upper end of the guide slot 37, as shown in figure 9, where further movement of the recliner support plate 32 is prevented by the pivot pin 36 acting on the upper end of the guide slot 37.

It is to be appreciated that the connection arrangement permits the recliner support plate 32 to pivot relative to the support plates 2,3 from a first orientation to a second orientation without the deformation of the frangible element 23. The connection arrangement thus allows for a component which supports a seat back to pivot without breaking or plastically deforming any elements.

After the seat back has pivoted forwardly, for instance following a frontal impact, the seat back may be returned to its normal, upright, position by fulfilling a second criterion. In this preferred embodiment the second criterion is fulfilled by exerting a force on the free end of the inner cable 49 of the Bowden cable 48 which is in excess of a predetermined level. The predetermined level is the level of force required to pivot the recliner support plate 32 back to its normal orientation. If a force is exerted on the end of the inner cable 49 connected to the motor 54, for example as a result of the motor being briefly operated, then the other end of the inner cable 49 acts on the pivot pin 36 via the blocking element 47 and the corresponding end of the outer sheath 50 acts on the recliner support plate 32 via the fixture 51. The forces exerted by the inner cable 49 on the pivot pin 36 and the recliner support plate 32 cause the recliner support plate 32 to pivot about the pivot pin 30 and to move relative to the pivot pin 36 to return the recliner support plate 32 to its initial position, as shown in figure 6. The force which must be exerted on the free end of the inner cable 49 is representative of a second criterion which must be fulfilled to permit the return means 46 to return the recliner support plate 32 from the second orientation to the first orientation. The pivoting arrangement is thus resettable, by selective energisation of the motor 54 so that the seat back may be returned to its normal position without having to replace components of the movement arrangement which might otherwise have been deformed unnecessarily.

If, following forward pivoting of the seat back by the pivoting arrangement, the seat occupant exerts a force on the seat back which is in excess of a predetermined level then the frangible release element 23 of the movement arrangement can still break to permit displacement of the recliner support plate 32, as shown in figure 10. Actuation of the movement arrangement following forward pivoting of the seat back could, for instance, become necessary if the vehicle is involved in a frontal impact and then is subsequently struck from the rear.

Operation of the oscillating haptic function of the recliner arrangement will now be described, with particular reference to figures 11 and 12.

Upon detection of an event or driving parameter of the type described above requiring the seat occupant's attention, the sensor 55 generates an actuating signal which is effective to energise the motor. The motor can be connected directly to the inner cable of the Bowden cable 48, in which case the motor is operated in a reciprocating manner so as to move the inner cable 49 within the outer sheath 50 in an oscillating manner. Alternatively, the motor can be connected to the inner cable 49 by an intermediate gearbox (not shown) in order to convert uni-directional rotation of the motor to reciprocating movement of the inner cable 49 within the outer sheath 50. In either case, therefore, it will be appreciated that operation of the motor in response to the actuating signal from the sensor 55 is effective to move the inner cable 49 within the outer sheath 50.

Movement of the inner cable 49 within the outer cable 50 this causes the pivot pin to move within the guide slot 37, in an oscillating manner, between the position illustrated in figure 11 , and the position illustrated in figure 12. It will be noted, in this regard, that in the position illustrated in figure 11 , the pivot pin is spaced slightly from the upper end of the guide slot 37, whilst in the position illustrated in figure 12 the pivot pin is spaced slightly from the lower end of the guide slot. It will thus be appreciated that the oscillating movement of the pivot pin 37 within the guide slot occurs over a range of movement which is reduced relative to the range of movement of the pivot pin which occurs in response to the first criterion being fulfilled, for example as a result of cargo in the rear of the vehicle or a rear-seat passenger striking the seat back during a frontal impact. Actuation of the motor 54 in the manner described above is thus effective to impart an oscillating pivotal movement to the back-rest of the vehicle seat in response to an appropriate signal from the sensor 55. This oscillating movement has a relatively small amplitude and thus serves to vibrate the back rest of the seat sufficiently to alert the driver, without adversely affecting the driver's driving position.

In a preferred embodiment of the haptic alert system of the present invention the actuating arrangement 53 is configured to impart an oscillating motion to the back rest of the vehicle seat in a predetermined series of bursts or "pulses", the pulses occurring in a "pulse-train". For example, it is envisaged that the pulse train might comprise three short bursts of oscillating movement, followed by a short break, and then followed by a further short burst of oscillating movement. It has been found that this sort of "on/off/on" pulse train can provide a clearer alert to a driver than continuous oscillation, thereby increasing the driver's likely response time to take appropriate corrective action.

In a preferred embodiment, at least the driver's seat in a motor vehicle is provided with a recliner mechanism of the type described above on each side. In such an arrangement, each recliner can be actuated independently so as to allow vibrations to be imparted to either side of the seat back independently, or even in combination. This can be useful in providing the driver of the vehicle with a haptic alert specific to the event requiring his or her attention. For example, the left-hand recliner could be actuated in response to the vehicle veering out of its line to the left, whilst the right-hand recliner could be actuated in response to the vehicle veering to the right.

Also, whilst the embodiment described above uses a Bowden cable to cause the oscillating movement of the back-rest in response to an actuating signal, other embodiments could use alternative actuating mechanisms to replace the Bowden cable arrangement. For example, embodiments are envisaged in which the Bowden cable is replaced with either a pneumatic or hydraulic actuator in the form of a piston/cylinder arrangement. Alternatively, a solenoid actuator could be used, or even a motor-driven arrangement.

It is also envisaged that in alternative embodiments, the deformable element 23 could take a different form. For example, whilst the embodiment has been described above with reference to the deformable release element 23 being engaged with the aperture 22 in the intermediate guide plate 15, and having a small extending fungible stud which locates in the aperture 28 formed in the pivot link 27, in the embodiment illustrated in figures 11 to 13, the deformable element takes the form of a spring 123. The spring 123 is formed from an elongate piece of spring wire and has a hooked end region 124 which is hooked over, and engages the upper edge of the intermediate support plate 15. From this point, the spring 123 extends towards the pivot pin 25 and is wrapped so as to take a single turn around the pivot pin 25, behind the plate 15 as shown. The spring then extends generally downwardly towards the pivot pin 30 where it terminates with a bent end region 125 bearing against the pivot 30.

In the initial condition illustrated in figure 3, with the pivot pin 36, at the lower end of the second pivot link 33 being located at a forward position within the generally triangular aperture 21 formed in the intermediate support plate 15, the spring 123 is effective, by virtue of its resiliency, to retain the support plate 15 and pivot link 27 in position relative to one another.

If the vehicle is subjected to a rear impact, a substantially rearwardly directed force is applied to the back of the seat. This initially causes the pivot links 27, 33 to commence a rearward pivoting motion. The rearward pivoting motion of the links is only permitted to proceed if the force applied to the back of the seat is sufficiently large to deform the spring 123 in the manner illustrated in figure 12. Thus, if the rear impact is only a very gentle rear impact, the seat remains in its initial condition, without any deformation of the spring 123. However, if the impact is of a predetermined severity, the spring 123 will deform, thus permitting the pivot links to move to the condition illustrated in figure 12.

It is to be understood that should a sufficient continuing rearward force be applied to the back of the seat to cause the second pivot link 33 to collapse, then the spring 123 is allowed to relapse slightly as the components assume the position illustrated in figure 13. Nevertheless, it remains the case that the predetermined threshold for the force that must be applied to the back of the seat to cause the second pivot link 33 to collapse is still greater than the force necessary to be applied to the back of the seat to deform the spring 123 thus permitting movement of the first pivot link from the position illustrated in figure 11.

As would be appreciated, by replacing the frangible release element 23 of the earlier embodiment with the deformable spring 123, the apertures 22, 28 formed in the intermediate support plate 15 and the first pivot link 27 respectively are no longer required and so these holes are not illustrated in the arrangement of figures 11 to 13.

It should be appreciated that whilst the preferred embodiments of the invention described above actually provide three distinct functions, namely i) haptic alert; ii) movement of the seat back in response to a rear impact; and iii) forward movement of the seat back in response to, for example, cargo or passengers impacting the rear of the seat in a frontal impact; in its broadest sense the present invention only requires the haptic alert function.

It has been found that providing a haptic alert to a seat occupant by vibrating the back rest of the seat, preferably in a pivotal manner, offers a number of advantages over prior art arrangements in which the squab of the seat is vibrated. For example, the arrangement of the present invention can be neatly incorporated in a recliner unit which can be relatively easily fitted to any one of a number of possible alternative seat frames, without necessitating a significant redesign of the seat frame. The back rest of a seat also lends itself well to haptic vibration because although a seat occupant can adopt many different seating positions, it is highly likely that in any probable seating position, the occupant's back will be in contact with the back rest.

Is will be appreciated, the present invention, which provides a haptic alert to a seat occupant via the back-rest of the seat also permits the incorporation of an anti-whiplash protection mechanism to protect the seat occupant from injury in the event of a rear-impact.

In the present Specification "comprises" means "includes or consists of and "comprising" means "including or consisting of".

While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.

Claims

1. A haptic alert system for a motor vehicle, the system comprising a seat back support mechanism for supporting the back of a seat in a motor vehicle, the seat back support mechanism having; at least one first component (2,3) adapted to be connected to the squab of the seat or to a frame supporting the squab of the seat; at least one further component (32) adapted to be connected to the back of the seat, the further component (32) being connected to the first component (2,3) by a connection arrangement configured to permit the further component (32) to move relative to the first component (2,3); the system further comprising an actuator arrangement (53) configured to move the further component (32) relative to the first component (2,3) in an oscillating manner.

2. A haptic alert system according to claim 1 , wherein the connection arrangement is configured to permit the further component (32) to pivot relative to the first component (2,3).

3. A haptic alert system according to claim 1 or claim 2, wherein the actuator arrangement (53) is configured to move the further component (32) pivotally relative to the first component (32) in said oscillating manner.

4. A haptic alert system according any preceding claim, wherein the actuator arrangement (53) comprises at least one alert sensor (55) configured to generate an actuating signal in response to the occurrence of an event or driving parameter requiring the seat-occupant's attention.

5. A haptic alert system according to any preceding claim, wherein the further component (32) is provided with an elongate guide slot (37), the guide slot (37) receiving slideably a guide member (36), the further component (32) being configured to move relative to the guide member (36) when the further component (32) moves relative to the first component (2,3).

6. A haptic alert system mechanism according to claim 5, wherein the length of the guide slot (37) is from 10 to 40 mm.

7. A haptic alert system according to claim 5 or claim 6, wherein the actuator arrangement (53) comprises a Bowden cable (48) which has an outer sheath (50) fixed relative to the further component (32) and an inner cable (49) fixed relative to the guide member 36) such that sliding movement of the inner cable (49) within the outer sheath (50) is effective to move the further component (32) relative to the guide member (36).

8. A haptic alert system according to claim 7, wherein the actuator arrangement (53) comprises an electric motor (54) configured to move said inner cable (49) within said outer sheath (50) in an oscillating manner in response to said actuating signal.

9. A haptic alert system according to any preceding claim, the connection arrangement of the seat back support mechanism further comprising a deformable element (23) configured to resist displacement of the further component (32) relative to the first component (2,3), the deformable element (23) being configured to deform in the event that a force in excess of a predetermined level is exerted on the further component (32) to permit displacement of the further component (32) relative to the first component (2,3), wherein the connection arrangement is configured to permit said oscillating movement of the further component (32) relative to the first component, without deforming the deformable element (23).

10. A haptic alert system according to claim 9, the connection arrangement being configured to permit the further component (32) to pivot relative to the first component (2,3) from a first orientation to a second orientation in response to fulfilment of a first criterion without deforming the deformable element (23); wherein the seat back support mechanism further comprises return means (46) which is configured to act on the further component (32) to return the further component (32) from the second orientation to the first orientation in response to fulfilment of a second criterion.

11. A haptic alert system according to claim 9, as dependant upon claim 5, wherein the guide member (36) is positioned at a first position along the length of the guide slot (37) when the further component (32) is in the first orientation and the guide member (36) is positioned at a second position along the length of the guide slot (37) when the further component (32) is in the second orientation.

12. A haptic alert system according to claim 10 or claim 11 , wherein said oscillating pivotal movement of the further component (32) relative to the first component (2,3) occurs about the same pivot point as the movement in response to fulfilment of said first criterion.

13. A haptic alert system according to claim 12, wherein the actuator arrangement (53) is configured such that said oscillating pivotal movement occurs over a range which is less than the full range of movement between said first and second orientations.

14. A haptic alert system according to any one of claims 10 to 13, wherein the connection arrangement further comprises a blocking element (47) which blocks movement of the further component (32) relative to the guide member (36), the blocking element (47) being releasable in response to fulfilment of the first criterion to permit movement of the further component (32) relative to the guide member (36).

15. A haptic alert system according to any one of claims 10 to 14, wherein the first criterion is a force exerted on the further component (32) which is in excess of a predetermined level.

16. A haptic alert system according to any one claims 10 to 15, wherein the second criterion is a force exerted on the return means (46) which is in excess of a predetermined level.

17. A haptic alert system according to claim 12 as dependent upon claim 7, wherein the return means (46) comprises said Bowden cable (48) such that the inner cable (49) moves the further component (32) relative to the guide member (36) when a force in excess of a predetermined level is exerted on one end of the inner cable (49).

18. A haptic alert system according to any one of claims 10 to 17, wherein the connection arrangement further comprises a biasing element (52) which biases the further component (32) towards the first orientation.

19. A haptic alert system according to claim 18, wherein the biasing element (52) is a spring.

20. A haptic alert system according to any one of claims 9 to 19, wherein the deformable element (23) is a frangible release element.

21. A haptic alert system according to any one of claims 9 to 19, wherein the deformable element (123) is a spring.

22. A haptic alert system according to any one of the preceding claims, wherein the further component (32) comprises a recliner support plate which supports a recliner mechanism (42).

23. A vehicle seat provided with a haptic alert system according to any preceding claim.