Seating furniture with height-adjustable headrest

1. A seating furniture, in particular an armchair or sofa, with at least one backrest, at least one headrest and at least one headrest adjustment, wherein the headrest is held adjustable by means of the headrest adjustment relative to the at least one backrest at least from a lower position into an upper position, wherein the headrest adjustment has two height-adjustable positioning struts bearing the headrest and each guided via a separate guide for adjusting the at least one headrest from the lower position into the upper position and back, wherein the guides each have a gear rack element and a gear wheel element meshing with the gear rack element when adjusting the headrest from the lower position to the upper position and back, and wherein the gear wheel elements are connected to one another in a torsion-resistant manner via a synchronous strut, and further wherein the positioning struts are connected to one another via at least one transverse strut which is height-adjustable together with the headrest and wherein the positioning struts are connected to the guides via the transverse strut.

2. The seating furniture according to claim 1 , wherein the synchronous strut is coaxially connected to the gear wheel elements and wherein the synchronous strut is arranged coaxially with the gear wheel elements.

3. The seating furniture according to claim 1 , wherein at least one gear rack element comprises several parts, in particular two parts, preferably identical parts, and wherein the at least two individual parts of the gear rack element are inserted into one another in an interlocking manner.

4. The seating furniture according to claim 1 , wherein at least one gear rack element has a series of recesses for mounting at least one end switch to limit an adjustment track of the headrest in various different positions, wherein an end switch has a push button for actuating in a direction at least substantially parallel to the synchronous strut and/or substantially parallel to the axis of rotation of the corresponding gear wheel element.

5. The seating furniture according to claim 1 , wherein at least one gear wheel element of one of the gear rack elements is configured to engage behind, in particular engage around, in an interlocking manner, while the headrest is adjusted from the lower position into the upper position and back, wherein at least one gear wheel element is directly or indirectly assigned a damping element which opposes the downwards adjustment of the headrest with a greater resistance than the upwards adjustment of the headrest.

6. The seating furniture according to claim 1 , wherein a lift adjuster for locking the headrest at least in the lower and/or upper position is provided and wherein the lift adjuster is connected to the transverse strut and/or the synchronous strut.

7. The seating furniture according to claim 6 , wherein the lift adjuster is configured to be locked in the gravitational direction in a clamped and/or interlocking manner at least in the lower and/or upper position, wherein the lift adjuster is configured to be locked in a stepwise manner at a plurality of positions between the lower and the upper position.

8. The seating furniture according to claim 1 , wherein the headrest adjustment is driven by means of a motorised drive from at least the lower position into the upper position and back, wherein the motorised drive is formed so as to rotate the synchronous strut and/or to drive at least one drive gear wheel meshing with a gear wheel element.

9. The seating furniture according to claim 8 , wherein the motorised drive is configured to be height-adjustable with the headrest adjustment and wherein the motorised drive is fixed on the synchronous strut and/or the transverse strut.

10. The seating furniture according to claim 1 , wherein the positioning struts are tilted forwards in relation to the seating furniture in the lower position of the headrest and the upper position of the headrest and wherein the positioning struts are tilted further forwards in the upper position of the headrest than in the lower position of the headrest and/or the positioning struts are held by the headrest adjustment so as to swivel between the lower position of the headrest and the upper position of the headrest, around the guide and/or the backrest.

11. The seating furniture according to claim 1 , wherein the headrest is provided pivotably at least from a rear position into a front position and wherein the headrest can be locked in the front position and/or the rear position via at least one locking hinge.

12. The seating furniture according to claim 11 , wherein a motorised drive is provided for pivoting the at least one headrest, wherein the motorised drive is integrated into the headrest and wherein a headrest gear wheel element of the motorised drive meshes with a curved gear rack element of a pivotable section of the headrest.

13. The seating furniture according to claim 11 , wherein at least one part of a positioning strut is configured to be rotatable via a motorised drive, wherein a transmission element is provided for transmitting the rotation of the positioning strut into a pivoting of the at least one headrest.

14. The seating furniture according to claim 1 , wherein the headrest adjustment is arranged at least in sections perpendicularly above at least one seat or seat cushion, wherein the positioning struts are spaced at least 0.5 m apart from one another, and wherein the seating furniture is formed as a piece of upholstered furniture.

15. A seating furniture, in particular an armchair or sofa, with at least one backrest, at least one headrest and at least one headrest adjustment, wherein the headrest is held adjustable by means of the headrest adjustment relative to the at least one backrest at least from a lower position into an upper position, wherein the headrest adjustment has two height-adjustable positioning struts bearing the headrest and each guided via a separate guide for adjusting the at least one headrest from the lower position into the upper position and back, wherein the guides each have a gear rack element and a gear wheel element meshing with the gear rack element when adjusting the headrest from the lower position to the upper position and back, and wherein the gear wheel elements are connected to one another in a torsion-resistant manner via a synchronous strut, and further wherein at least one gear rack element has a series of recesses for mounting at least one end switch to limit an adjustment track of the headrest in various different positions, wherein an end switch has a push button for actuating in a direction at least substantially parallel to the synchronous strut and/or substantially parallel to the axis of rotation of the corresponding gear wheel element.

16. A seating furniture, in particular an armchair or sofa, with at least one backrest, at least one headrest and at least one headrest adjustment, wherein the headrest is held adjustable by means of the headrest adjustment relative to the at least one backrest at least from a lower position into an upper position, wherein the headrest adjustment has two height-adjustable positioning struts bearing the headrest and each guided via a separate guide for adjusting the at least one headrest from the lower position into the upper position and back, wherein the guides each have a gear rack element and a gear wheel element meshing with the gear rack element when adjusting the headrest from the lower position to the upper position and back, and wherein the gear wheel elements are connected to one another in a torsion-resistant manner via a synchronous strut, and further wherein at least one gear wheel element of one of the gear rack elements is configured to engage behind, in particular engage around, in an interlocking manner, while the headrest is adjusted from the lower position into the upper position and back.

17. The seating furniture according to claim 16 , wherein at least one gear wheel element is directly or indirectly assigned a damping element which opposes the downwards adjustment of the headrest with a greater resistance than the upwards adjustment of the headrest.