WO2023281253A1

WO2023281253A1 - Head rest

Info

Publication number: WO2023281253A1
Application number: PCT/GB2022/051724
Authority: WO
Inventors: Harry GROSVENOR-COLLIS
Original assignee: Bentley Motors Limited
Priority date: 2021-07-09
Filing date: 2022-07-05
Publication date: 2023-01-12
Also published as: GB2608804A; GB202109960D0

Abstract

A head rest (4) includes a first support surface (16) for supporting a user's head, and a deployable structure (37) which is moveable from a stowed position to a deployed position. The deployable structure (37) includes a second support surface for supporting a user's head which. When the deployable structure (37) is in the deployed position, it extends laterally adjacent the first support surface of the head rest (4) in order to increase the effective width of the head rest (4). The head rest (4) includes an actuator (24) operable to move the deployable structure (37) from the stowed position towards the deployed position. The deployable structure (37) is at least partially retained within the remainder of the head rest (4) when in the stowed position. A seat (1) and vehicle (101) including the head rest (4) are also described.

Description

HEAD REST

Technical Field of the Invention

The present invention relates to a head rest for use in vehicles, particularly but not exclusively, road vehicles such as automobiles.

Background to the Invention

Vehicles, particularly automobiles, may be subject to collisions which can cause occupants of the vehicle to experience a large force in a short period of time. This can lead to injuries being sustained. Whiplash is a common injury suffered in collisions between vehicles. Whiplash is a neck injury that can occur when a person’s head is suddenly thrown forwards, sideways or rearward, resulting in an overextension of the soft tissues in the neck.

To reduce the risk of whiplash occurring in vehicular collisions, vehicle seats are fitted with head rests in order to support the occupant’s head in the event of a collision.

However, current head rests in vehicles only support the occupant’ s head in case of motion directly towards the rear of the vehicle, which is commonly caused by collisions which occur in the same direction as the direction of travel. If a collision occurs at an oblique angle to the direction of travel this is likely to cause an occupant’s head to move with a component of movement in a lateral direction within the vehicle in which case current head rests may not support the occupant’ s head and whiplash may occur. In particular, an occupant’s head may move past a head rest or just strike an edge of the head rest. Head rests are generally narrower than a back rest of a seat to which they are fitted so as not to impede lines of sight of occupants of the vehicle.

The problems associated with existing headrests are increased if they are not correctly adjusted for a particular user. Often head rests are neither easy nor quick to adjust. Where an automobile has multiple users who require different positioning of the headrest to optimise the protection available it is inconvenient to adjust the headrest each time the user changes. Consequently, users may not adjust the head rest to their needs, compromising their safety. Also, some current head rests do not adjust enough to take into account some driving positions. This also affects a vehicle user’s safety and typically has a greater impact on women as it is common for vehicle seats to be designed around greater average male, rather than female, height resulting in seats and headrests that cannot be adjusted into an optimal position for some women occupants.

It is an object of embodiments of the present invention to alleviate or overcome the above issues with existing head rests.

Summary of the Invention

According to a first aspect of the present invention, there is provided a head rest comprising a first support surface for supporting a user’s head, and a deployable structure which is moveable relative to the first support surface from a stowed position to a deployed position, the deployable structure comprising a second support surface for supporting a user’s head which, when the structure is in the deployed position, extends laterally adjacent the first support surface of the head rest in order to increase the effective width of the head rest.

Increasing the lateral width of the head rest increases the chance that it can support a vehicle occupant’s head in the event of a collision, or other sudden acceleration or deceleration event, even if the headrest is not optimally adjusted for the occupant. The deployable structure may only be deployed when required so that the head rest does not always have an increased width, which could cause it to obstruct the view of vehicle occupants or interfere with their movement in the vehicle or adjustment of a seat to which the headrest is fitted.

The deployable structure may be movably mounted to the remainder of the head rest. The moveable mounting may permit movement of the deployable structure between its stowed and deployed positions, and may only permit movement between those positions. The head rest may comprise an internal supporting structure. The deployable structure may be movably mounted to the internal supporting structure. The deployable structure may be slidably mounted to the remainder of the headrest, or an internal supporting structure of the headrest.

The deployable structure may comprise a substantially rigid structure. The substantially rigid structure may be at least partially covered with a softer material. The softer material may be an energy absorbing material. One example of a suitable energy absorbing material is a foam, such as expanded polystyrene.

The first support surface may comprise a cushioned portion. The second support surface may comprise a cushioned portion. The second support surface may have a surface area at least 20%, 30%, 40% or 50% of the surface area of the first support surface. The second support surface may have a width of at least 20%, 30%, 40% or 50% of that of the first support surface. The surface area or width of the second support surface may be of that part of the second support surface portion which is exposed when the deployable structure is in the deployed position.

The head rest may comprise at least one actuator operable to move the deployable structure from the stowed position towards the deployed position. The deployable structure may be moveable mounted to the remainder of the head rest or an internal support structure of the head rest by way of the actuator.

The actuator may be operated by a trigger. The trigger may be disposed on the headrest, such as housed within the head rest, or remote from the headrest. The trigger may be a vehicle crash recognition system. The trigger may comprise a trigger mechanism, such as an inertia latch. The trigger could be electrical and/or mechanical.

The actuator may comprise a piston and cylinder device. The piston and cylinder device may be operable by compressed gas and/or by a pyrotechnic substance. The actuator may comprise a pyrotechnic actuator.

The actuator may comprise a solenoid.

The actuator may comprise a resilient member, such as a spring, arranged to urge the deployable structure towards the deployed position. A releasable latch may retain the deployable structure in the stowed position, such that on release the resilient member can move the deployable structure towards the deployed position. The releasable latch may be released by an actuator, such as a solenoid.

The head rest may comprise a guide rail arranged along which the deployable structure moves between the stowed and deployed positions. The deployable structure may be at least partially retained within the remainder of the head rest when in the stowed position. The headrest may comprise an outer body defining a cavity or recess. The deployable structure may be substantially received into the cavity or recess when in the stowed position. The deployable structure may extend out of the cavity or recess when in the deployed position. The deployable structure may be sized and shaped so that when in the stowed position it fits within and completes the outline shape of the headrest.

The first support surface may be generally flat. The second support surface may be generally flat.

According to a second aspect of the present invention, there is provided a head rest comprising a first support surface for supporting a user’s head, and a deployable structure which is moveably mounted to the remainder of the headrest such that it is moveable relative to the first support surface from a stowed position to a deployed position, the deployable structure comprising a second support surface for supporting a user’s head adjacent the first support surface of the head rest in order to increase the effective area of the head rest.

According to a third aspect of the present invention, there is provided a seat comprising the head rest of the first or second aspect of the present invention.

According to a fourth aspect of the present invention, there is provided a vehicle comprising at least one head rest according to the first or second aspect of the present invention and/or at least one seat according to the third aspect of the present invention.

The vehicle may comprise a crash recognition system. Such systems are known and detect when a vehicle encounters or is about to encounter a sudden acceleration or deceleration event such as a collision in order to trigger active safety devices, such as air bags. When such an event is detected the crash recognition system may be arranged to cause the deployable structure of the head rest to move from the stowed position towards the deployed position. As such, the second support surface is exposed and in a position to support the head of a vehicle occupant, reducing their risk of injury.

The vehicle may be an automobile.

Detailed Description of the Invention In order that the invention may be more clearly understood one or more embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

Figure 1 is a perspective view of a seat comprising a head rest; Figure 2 is perspective view of the head rest of figure 1 with a deployable structure in a stowed position;

Figure 3 is a perspective view of the head rest of figure 1 with the deployable structure in the deployed position;

Figure 4 is a front elevation of the head rest of figure lwith the deployable structure is in the stowed position, without the external housing;

Figure 5 corresponds to figure 4, but with the deployable structure in the deployed position;

Figure 6 is an exploded perspective view of the head rest of figure 1; and Figure 7 is a schematic illustration of an automobile. In the drawings, like features are denoted by like reference numerals throughout.

In what follows the terms up, down, top, bottom, front, rear and like terms refer to the illustrated seat and head rest in the orientation in which it is shown, which is the orientation in which they are intended to be used, but should not be taken as otherwise limiting. The terms left and right are used from the perspective of an observer viewing the seat and head rest from the front.

Referring to the drawings, a vehicle seat 1 comprises a squab 2, a back rest 3 and a head rest 4 mounted to the top of the back rest.

The head rest 4 comprises a mild steel stem assembly 5. The stem assembly 5 comprises two supporting rods 6. The rods 6 to connect the head rest 4 to the back rest 3 of the seat 1. The two supporting rods 6 are elongate and have substantially parallel straight portions 7 with free ends 8 which are received into respective cavities (not shown) in the back rest 3 so as to mount the head rest 4 to the back rest 3. Each supporting rod 6 has a circular cross section. At the opposite end 9 of the straight portion 7 of each rod 6, the rod 6 turns through approximately 90 degrees and extends for a length approximately 10% of that of the straight portion 7. This forms a second, shorter portion 10, at the end of which the rod 6 turns through a second approximately 90 degree turn, away from the free end 8 of the rod 6, and extends away from the shorter portion 7 for about the length of the shorter portion 7.

Attached to the uppermost portion 11 of each supporting rod 6 is a connecting plate 12. The connecting plate 12 comprises an elongate rectangular main portion 13 which is bent through 90 degrees at each opposite end to form and a pair of flanges 14. A pair of symmetrically aligned holes 15 are formed through the main portion 13. Each hole is situated approximately 25% of the length of the main portion 13 from a respective end of the main portion 13.

The uppermost portion 11 of each supporting rod 6 is disposed within the shoulder formed between each flange 14 and the main portion 13. The shorter elongated portion 10 of each supporting rod 6 is aligned substantially parallel the flanges 14 of the connecting plate 12.

Attached to the connecting plate 12 is an internal support structure 16 formed from a magnesium alloy. The internal support structure 16 comprises a symmetric trapezoidal plate 17 having a pair of holes 18a along the longer of the two parallel sides of the plate 17. The longer of the parallel sides of the plate 17 forms the bottom edge of the plate, and the shorter of the parallel sides forms the top edge of the plate 17. The longer edge is approximately one third longer than the shorter edge.

The holes 18a are arranged in the plate 17 such that they are the same distance apart from each other as the holes 15 in the connecting plate 12. This allows a suitable fastening means (not shown) to attach the internal support structure 16 to the connecting plate 12.

Four elongate rectangular apertures 18b are formed in the plate 17. Each rectangular aperture extends generally vertically. Two apertures are formed towards each of the top comers of the plate, and a respective aperture is formed below each of these two apertures, toward the bottom edge of the plate, so that the apertures form a rectangular array. The plate 17 comprises three larger apertures 19a, b. Each aperture 19a, b has a height approximately 40% of that of the distance from the longer side of the plate 17 to the shorter side of the plate 17. The apertures 19 are aligned at the same height within the plate 17, approximately the same distance from the longer edge of the plate 17 as the height of the apertures 19. The shorter edges of the apertures 19 a, b are parallel to the longer and shorter (bottom and top) edges of the plate 17.

The apertures 19 comprise a pair of rectangular apertures 19a. The rectangular apertures 19a have a width that is approximately one third of their height. The rectangular apertures 19a are identical.

The third aperture 19b has an irregular quadrilateral shape, comprising two edges (the bottom and inner most edges) which are identical to the equivalent edges of the rectangular apertures 19a, whilst the outer most edge of the aperture 19b is substantially parallel to the diagonal outer edge of the plate 17. The top most edge of the third aperture 19b is approximately three quarters of the length of the bottom edge of the apertures 19a.

When viewing the support structure 16 from the front, i.e. the direction in which the seat 1 faces, the right-hand edge of the right-hand rectangular aperture 19a is aligned with the comer between the shorter and right-hand diagonal edges of the plate 17.

The right-hand edge of the other rectangular aperture 19a is situated a distance of approximately twice the width of each rectangular aperture 19a away from the left most edge of the right-hand rectangular aperture 19a.

The right-hand edge of the third aperture 19b is positioned a distance approximately equal to one width of the rectangular apertures 19a from the left-hand edge of the left-hand rectangular aperture 19a.

The internal support stmcture 16 also comprises a pair of hollow box section protrusions 20 which extend rearwardly from the rear surface of the plate 17. The cross- section of the protrusions 20 corresponds in size and shape to the rectangular apertures 19a.

Each protmsion 20 extends away from the plate 17 a distance approximately twice the width of each rectangular aperture 19a. A hole 21 is formed through the centre of each of the narrow sides of each protrusion 20. Each protrusion 20 has an end surface 22 in a plane parallel to the plate 17, and comprises a pair of arcuate recesses 23 which extend into the end surface 22 of each of the longer walls of each protrusion 20, adjacent the shorter sides of the protrusion 20.

A pair of actuators 24 are disposed in the recesses 23, where they are secured by a pair of brackets 25.

Each actuator 24 comprises an elongate aluminium alloy cylinder 26 formed by a hollow cylindrical tube, having a length which is approximately the same as four times the width of each aperture 19a, i.e. the distance between the two most distant walls of the protrusions 20.

Each bracket 25 is substantially m-shaped, having two elongate legs 27 which each curve through an approximately 180-degree bend 28, with a radius substantially the same as the outer radius of each actuator 24. The two bends 28 are connected via a shorter connecting portion 29 which extends at approximately 90 degrees to the legs 27. Each leg 27 has a hole 30 adjacent its free end.

The distance between the elongate legs 27 of the bracket 25 is approximately the height of each aperture 19 in the plate 17, such that the bracket 25 can be placed inside the protrusion 20 with a close fit.

The holes 30 in each bracket 25 are positioned such that when the bracket 25 is placed in the protrusion 20, they align with the holes 21 in the protrusion 20. A suitable fastening means (not shown) is used to fasten the brackets 25 in the protrusions 20. This forms two substantially circular cavities between the recesses 23 in the end surface 22 of the protrusion 20 and the bends 28 in the bracket 25. The actuators 24 are disposed within these cavities, and are securely retained within it when the suitable fastening means is applied through the respective holes 21,30 in the protrusion 20 and bracket 25 respectively.

Each actuator cylinder 26 contains an aluminium alloy actuator piston 31. The actuator piston 31 comprises a cylindrical body 32 with a flange 33 at one end. The cylindrical body 32 has a length one third larger than that of the actuator cylinder 26. The diameter of the cylindrical body 32 of the actuator piston 31 is approximately half that of the actuator cylinder 26. The flange 33 has a diameter approximately equal to the inner diameter of the actuator cylinder 26 such that it has a close sliding fit. The actuator cylinder 26 comprises a mechanical stop (not shown) in operative to retain the actuator piston 31. An example of a suitable mechanical stop is a taper lock. A cap 34 is attached to the right-hand side of the actuator cylinder 26 (when viewing the head rest 4 from the front) facing the flanged end of the piston 31. The opposite end of the cylinder 26 is open. The cap 34 comprises a cylindrical tube 35 with one closed end around which a flange extends. The cylindrical tube 35, has a length approximately equal to its radius. The tube 35 has a diameter approximately equal to that of the inner diameter of the actuator cylinder 26, such that the cap 34 is retained at the end of the actuator cylinder 26 with an interference fit.

An explosive compound such as sodium azide (not shown) is disposed in the cap 34 and electrically connected to a suitable detonator. Alternately, a compressed gas supply, for example a pressured canister (not shown), may be disposed in or be fluidly connected to the cap 34 in order to deploy the actuator 24. The actuator 24 is connected to the vehicle’s crash recognition system 36, which will be understood by the skilled person. The crash recognition system 36 will, upon detection of a crash (or certain categories of crash) involving the vehicle, activate the actuator 24 detonating the explosive compound. This will urge the pistons out of the cylinders, increasing the distance which the pistons 31 extends out of the actuator cylinders 26, to the point where further movement of the pistons out of the cylinders is arrested by the mechanical stop.

The ends of the pistons 31 which protrude from the actuator cylinders 26 are attached to a deployable structure 37. The structure 37 comprises a body moulded from a plastics material, such as poly carbonate or ABS, having a flat, rectangular bottom surface with width approximately one quarter longer than its length, and a flat front surface extending at right angles to the bottom surface with a height approximately 1.5 times its width. An arcuate rear surface extends between the front and bottom surfaces. The left-hand side of the deployable structure 37 is closed, by a planar surface which connects the top, bottom, front and rear surfaces and the right-hand surface is open. The protruding portion of each actuator piston 31 is received in the open right-hand surface of the deployable structure 37. The deployable structure 37 is substantially hollow, save for a pair of arcuate fins in which the actuator pistons 31 sit, to ensure the deployable structure 37 is properly aligned with the actuator pistons 31. The deployable structure 37, in its front surface, comprises a recess extending from its right-hand edge approximately one quarter of the length of the front side of the deployable structure 37. The recess has a height approximately equal to that of the protrusions 20, to allow the deployable structure 37 to have a close, sliding fit with the left-hand protrusion 20 when viewed from the front of the head rest 4.

An impact cushioning block 38 is disposed around the deployable structure 37. The outer shape of the impact cushioning block 38 is generally the same as that of the deployable structure 37, save that the front facing side of the block 38 is an irregular quadrilateral, having two parallel sides of differing length, the bottom edge being approximately one quarter longer than the top edge, so that the left-hand edge of the block 38 is angled.

The impact cushioning block 38 comprises a pair of recesses, the larger of which is shaped and sized to receive and retain the structure 37 with a close fit. This larger recess is formed in the right-hand surface of the block 38. The second recess in the impact cushioning block 38 extends from the right-hand edge of the front surface of the impact cushioning block 38 and into the block 38 by approximately the same distance as the corresponding recess within the deployable structure 37. Similarly, this recess also allows for the impact cushioning block 38 to have a close, sliding fit with the left- hand protrusion 20 when viewed from the front of the internal support structure 16.

The impact cushioning block 38 may be bonded to the deployable structure.

The impact cushioning block 38 is formed from an impact absorbing material suitable to absorb energy from a user’s head. The skilled person will understand that there are many suitable materials which could be used. In this embodiment, the impact cushioning embodiment 38 is formed from expanded polystyrene.

The actuators 24 serve to movably mount the deployable structure 37 and impact absorbing block 38 to the trapezoidal plate 17, for movement between a stowed position where the deployable structure 37 is adjacent the left hand protrusion 20 and the pistons 31 are received into the cylinders 26 to, or near, a maximum extent and a deployed position where the pistons 31 are urged out of the cylinders 26 to a maximum extent. The cylinders 26 are arranged so that the flanges 33 of the pistons 31 are held captive within the cylinders 26.

Disposed around the support structure 16 is an external housing 39 moulded from polypropylene. The external housing 39 comprises front and rear sections 40,41 which form the main body of the head rest 4. The front section 40 of the housing 39 comprises a front-facing, symmetrical trapezoidal plate which forms a support surface for supporting an occupant’s head. The top and bottom edges of the trapezoidal plate are parallel, with the bottom edge being approximately one third larger than the top. The side walls of the front section 40 of the housing 41 extend approximately one third of the length of the top edge towards the rear of the head rest 4, forming a shallow open box with a trapezoidal base. The top wall of the front section 40 comprises a slight downward curve, which matches the profile of the initial curve in the upper surface of the impact cushioning section 38.

The left hand and top walls of the front section 40 of the housing 39 comprise a recessed portion which extends continuously from approximately the middle of the top wall to a point approximately one quarter of the length of the left-hand edge from the bottom edge of the front section 40 of the housing 39. The recess extends approximately half way into the top and side walls, and is defined by a sharp, right angled step at its end points in the top and side walls.

Comprised on the inner portion of each wall of the front section 40 is a one half of a suitable fastening means 42. In this embodiment, this is the receiving portions 42a of multiple push fit connectors. Particularly, there are seven receiving portions 42a in this embodiment. One is positioned within the left-hand wall, two along the bottom wall, three on the right-hand wall, and a single receiving portion 42a on the top wall.

The dimensions of the front section 40 are such that when the front section 40 is placed over the internal support structure 16, the trapezoidal plate 17 of the internal support structure 16 is enclosed within the hollow portion of the front section 40. The recess in the front section of the housing 39 is formed such that when the front section 40 is placed over the internal support structure 16, the impact cushioning block 38 of the head rest 4 matches the profile of the front section 40 in a close sliding fit. The front section 40 comprises a set of four tangs (not shown) integrally moulded into the interior surface of the front section 40. The tangs extend into the cavity defined by the front section 40 and are positioned such that they are received by rectangular apertures 18b formed in the trapezoidal plate 17 of the support structure 16.

The tangs are securely retained within the aperture 18b through the attachment of a metal spring clip to each tang. These tangs and respective clips securely attach the front section 40 of the housing 39 to the internal support structure 16 of the headrest 4.

The rear section 41 of the housing 39 comprises a hollow box having a curved trapezoidal plate forming its rear wall. The top and bottom edges of the trapezoidal plate are parallel, with the bottom edge being approximately one sixth larger than the top. The angle of the left- and right-hand edges of the trapezoidal plate of the rear section 41 relative to the bottom edge of the trapezoidal plate are substantially the same as the angle between the angle of the left- and right-hand edges of the trapezoidal plate of the rear section relative to the bottom edge of the trapezoidal plate of the front section 40. The rear wall comprises a recess spanning approximately a quarter of its area, in its upper left quadrant as defined by the area of intersection between the upper half and left half of the trapezoidal plate, when viewed from the front.

The curve of the upper wall of the rear section 41, in its initial portion, matches the curve in the upper wall of the front section 40. This curve extends continuously to the top edge of the rear wall. The recess defined in the rear wall continues into the upper wall, and extends to the edge of the upper wall of the rear section 41. The profile of the upper wall of the rear section 41 matches that of the upper surfaces of the front section 40 and the impact cushioning block 38. The left-hand wall of the rear section 41 extends to the same height as the left-hand wall of the front section 40. And the profile of the left-hand wall of the rear section 41 matches that of the left-hand wall of the front section 40 and the impact cushioning section 38.

As such, when the deployable structure 37 and impact absorbing block 38 is in the storage position its exposed surfaces are flush with the adjacent surfaces of the housing 39 and the head rest 4 appears to be formed from a single continuous piece of material. In use, the head rest 4 may be upholstered, such that a user may not recognise that the head rest 4 comprises a deployable portion, and to provide an attractive appearance for the head rest 4. In this case it will be understood that the actuator 24, upon activation, shall provide enough force to break through the upholstery and allow the deployable portion reach the deployed position. To facilitate this a line of weakness may be provided in any upholstery, surrounding the deployable structure.

Comprised on the inner portion of each wall of the rear section 41 is the other half of each of the fastening means 42 of the front section 40. In this embodiment, this is the insertion portions 42b of the multiple push fit connectors. Particularly, there are seven insertion portions 42b in this embodiment. One is positioned within the left-hand wall, two along the bottom wall, three on the right-hand wall, and a single insertion portion 42b on the upper wall, located directly opposite those on the front section 40 to allow attachment of the rear section 41 to the front section 40.

. The insertion portions 42b sit around the outer edge of the trapezoidal plate 17. The receiving portions 42a of the front section 40 then connect to respective insertion portions 42b of the rear section 41, allowing the housing 39 to fit securely around the internal support structure 16.

The front section 40 of the housing 39 is placed over and connected to the internal support structure 16 such that it encloses the trapezoidal plate 17. The rear section 41 is then attached to the front section using the push fit connectors.

In use, the head rest 4 is installed with the deployable structure 37 and impact absorbing block 38 in the stowed position, so that the head rest 4 appears largely like a conventional one.

The actuators 24 are connected to the crash detection system 36 of a vehicle 101 in which the head rest 4 is mounted.

In the event that a crash or impending crash or some other rapid acceleration or deceleration event is detected the crash detection system 36 triggers the actuators 24, in this example detonating the explosive compound. This causes a rapid build-up of gas behind the pistons 31 urging them out of their cylinders 26, and thus moving the deployable structure 37 and impact absorbing block 38 to the deployed position to the left of the head rest 4, as shown in Figure 2. This exposes the front, support, surface of the impact absorbing block 38 to the left side of the head rest 4. This additional surface is thus available to support and occupant’ s head in the event that their head is propelled rearwardly and to the left side of the head rest 4. Provision of an increased laterally extending support surface thus reduces the likelihood of a whiplash or other injury being sustained. As the impact absorbing block 38 is only deployed if a crash is detected it does not impair the appearance of the head rest 4 or restrict vehicle occupants’ line of sight during normal use of the vehicle 101.

The one or more embodiments are described above by way of example only. In particular, the above embodiment is designed for the passenger seat of a right-hand drive vehicle, such that the deployable portion is arranged to deploy into the inboard free space of the vehicle. The skilled person would understand that a mirrored version of the above embodiment would be suitable for use in the opposite seat, such that the mirrored deployable portion also deploys into the inboard free space. The skilled person would further understand that the deployable portion could extend in the outboard direction by fitting the above described head rest to the relevant seat. Many variations are possible without departing from the scope of protection afforded by the appended claims.

Claims

1. A head rest comprising: a first support surface for supporting a user’s head; and, a deployable structure which is moveable relative to the first support surface from a stowed position to a deployed position, the deployable structure comprising a second support surface for supporting a user’ s head which, when the structure is in the deployed position, extends laterally adjacent the first support surface of the head rest in order to increase the effective width of the head rest.

2. A head rest as claimed in claim 1 wherein the deployable structure comprises a substantially rigid structure.

3. A head rest as claimed in claim 2 wherein the substantially rigid structure is at least partially covered with a softer material.

4. A head rest as claimed in any preceding claim wherein the deployable structure is movably mounted to remainder of the head rest.

5. A head rest as claimed in any preceding claim wherein the head rest comprises an internal supporting structure and the deployable structure is movably mounted to the internal supporting structure.

6. A head rest as claimed in any preceding claim wherein the support surface of the deployable structure comprises a cushioned portion.

7. A head rest as claimed in any preceding claim wherein the second support surface has a surface area at least 20% of the surface area of the first support surface.

8. A head rest as claimed in any preceding claim comprising at least one actuator operable to move the deployable structure from the stowed position towards the deployed position.

9. A headrest as claimed in claim 8 wherein the at least one actuator comprises a piston and cylinder assembly.

10. A head rest as claimed in claim 8 or claim 9 wherein the at least one actuator comprises a pyrotechnic actuator.

11. A head rest as claimed in claim 8 or 9 wherein the actuator is actuated using a compressed gas.

12. A head rest as claimed in claim 8 wherein the at least one actuator comprises a solenoid.

13. A head rest as claimed in any of claims 8-12 wherein the at least one actuator comprises a resilient member.

14. A head rest as claimed in any of claims 8-13 where the actuator is connected to a trigger.

15. A head rest as claimed in claim 14 wherein the trigger is an inertia latch.

16. A head rest as claimed in claim 14 wherein the trigger is a vehicle crash recognition system.

17. A head rest as claimed in any preceding claim wherein the head rest comprises a guide rail arranged along which the deployable structure moves between the stowed and deployed positions.

18. A head rest as claimed in any preceding claim, wherein the deployable structure is at least partially retained within the remainder of the head rest when in the stowed position.

19. A head rest as claimed in any preceding claim wherein the first support surface is generally flat.

20. A head rest as claimed in any preceding claim wherein the second support surface is generally flat.

21. A seat comprising a head rest as claimed in preceding claim.

22. A vehicle comprising at least one head rest as claimed in any of claims 1-20 and/or at least one seat as claimed in claim 16.

23. A vehicle as claimed in claim 22 comprising a crash recognition system wherein the head rest is arranged to deploy the deployable structure from the stowed position towards the deployed position when the crash recognition system determines that the vehicle is subject to or about to be subject to a crash.