Head restraint assembly

1. A head restraint assembly for a vehicle seat, the head restraint assembly comprising:

a housing;

a movable head rest portion which defines at least a part of a rest surface for a seat user's head; and

a linkage mechanism pivotally mounting the movable head rest portion to the housing,

wherein the linkage mechanism is configured to allow movement of the movable head rest portion to enable an angle of the rest surface to be adjusted relative to the housing,

wherein the linkage mechanism includes first and second linkage bars,

wherein the first linkage bar is pivotally coupled to the housing via a sliding pin and the sliding pin is configured to engage a runner within the housing,

wherein the runner comprises at least a first recess configured to receive the sliding pin to secure the head rest portion in a first deployed position and a second recess configured to receive the sliding pin to secure the head rest portion in a second deployed position,

wherein the first linkage bar is pivotally mounted to the movable head rest portion at a forward end of the first linkage bar and the sliding pin is engaged with the runner at a rearward end of the first linkage bar,

wherein the second linkage bar is pivotally mounted to the movable head rest portion at a forward end of the second linkage bar to define a pivot axis of the movable head rest portion,

wherein the second linkage bar is mounted to the housing at a rearward end of the second linkage bar,

wherein the first and second linkage bars are pivotally coupled via a connecting pin,

wherein the connecting pin is received within an aperture provided in the first or second linkage bar,

wherein the aperture comprises a slot and the slot is configured to guide movement of the connecting pin along a length of the first linkage bar or the second linkage bar as the head rest portion is adjusted relative to the housing,

wherein the movable head rest portion is pivotal about the pivot axis by causing a first end of the movable head rest portion to move toward or away from the housing, and

wherein the linkage mechanism is configured such that the pivot axis moves away from the housing when the first end of the movable head rest portion is moved away from the housing.

2. The head restraint assembly as claimed in claim 1 , wherein the housing defines a recess and wherein the movable head rest portion is pivotally movable relative to the housing between a stowed position in which it resides within the recess and the first and second deployed positions in which at least a first end of the movable head rest portion is displaced away from the housing.

3. The head restraint assembly as claimed in claim 1 , wherein an upper portion of the rest surface is defined by the housing and a lower portion of the rest surface is defined by the movable head rest portion.

4. The head restraint assembly as claimed in claim 1 , wherein the forward end of the first linkage bar is pivotally mounted to the movable head rest portion via a friction hinge.

5. The head restraint assembly as claimed in claim 1 wherein the sliding pin is arranged to enable the rearward end of the first linkage bar to slide perpendicularly relative to a fore-aft direction of the seat.

6. The head restraint assembly as claimed in claim 1 , wherein the housing defines two runners arranged to be located on either side of the rearward end of the first linkage bar, and the first linkage bar comprises two sliding pins configured to engage the two runners.

7. The head restraint assembly as claimed in claim 1 , wherein the runner comprises at least one other recess configured to secure the head rest portion in the stowed position.

8. The head restraint assembly as claimed in claim 7 , wherein the runner comprises at least one further recess configured to secure the head rest portion in at least one intermediate position.

9. The head restraint assembly as claimed in claim 1 , wherein the sliding pin is spring loaded.

10. The head restraint assembly as claimed in claim 1 , wherein the housing is movable in an up-down direction relative to the seat, wherein the head restraint assembly comprises a first motor for controlling movement of the housing in the up-down direction, and wherein the first motor is housed within the housing.

11. The head restraint assembly as claimed in claim 10 , comprising a second motor for controlling aft-fore and fore-aft direction movement of the housing, wherein the second motor is housed within the housing.

12. The head restraint assembly as claimed in claim 11 , wherein the second motor has a solid spindle connection.

13. The head restraint assembly of claim 1 , wherein

the linkage mechanism is configured to allow pivotal movement of the movable head rest portion to enable the angle of the rest surface to be adjusted relative to the housing;

the housing defines a recess; and

the movable head rest portion is pivotally movable relative to the housing between the first and second deployed positions in which at least a first end of the movable head rest portion is displaced away from the housing and a stowed position in which the movable head rest portion resides within the recess.

14. A seat assembly comprising the head restraint assembly as claimed in claim 1 .

15. A vehicle comprising the seat assembly of claim 14 .

16. The head restraint assembly of claim 1 , wherein

the first linkage bar is pivotally mounted to the moveable headrest portion near a second end of the moveable headrest portion;

the linkage mechanism is configured such that the pivot axis and the first end of the moveable headrest portion move a larger distance from the housing than the second end of the moveable headrest portion.

17. The head restraint assembly of claim 16 , wherein the first end of the moveable headrest portion is near a top of the head restraint assembly and the second end of the moveable headrest portion is near a bottom of the head restraint assembly.

18. The head restraint assembly of claim 1 , wherein the forward end of the second linkage bar moves further from the housing than the forward end of the first linkage bar as the moveable headrest portion pivots about the pivot axis and moves away from the housing.