Device and method for detection of collisions in furniture

1. A device for recognizing collisions of automatically moveable parts of furniture with obstacles, comprising:

a piece of furniture with at least one moveable part, wherein this part is adapted to be moved relatively to the remaining piece of furniture in a non-manual manner,

an automatic driving mechanism adapted to move the moveable part,

a controller adapted to control the automatic driving mechanism, and

a sensor adapted to detect a collision with an obstacle during the movement of the moveable part and to transmit the collision to the controller,

wherein the sensor is adapted to detect a change in bend of the moveable part.

2. A device according to claim 1 , wherein the sensor contains a piezoelectric material.

3. A device according to claim 2 , wherein the sensor is a piezoelectric diaphragm.

4. A device according to claim 1 , wherein the sensor is arranged at the moveable part at an attachment location, at which a higher than average bending moment is applied in a case of a collision.

5. A device according to claim 4 , wherein the sensor is attached at the moveable part at an attachment location, at which a higher than average deflection is applied instead of the bending moment during a case of a collision.

6. A device according to claim 4 , wherein the piece of furniture is a table adjustable in height, the table including at least one table leg adjustable in height, and the attachment location is arranged at the upper end region thereof.

7. A device according to claim 4 , wherein the piece of furniture is a table adjustable in height, comprising at least one table leg adjustable in height, the table leg being hollow, and the attachment location is arranged at an inner side seen in a radial direction.

8. A device according to claim 4 , wherein the piece of furniture is a table adjustable in height, comprising at least one table leg adjustable in height, at the upper end of which an additional plate is provided, and the attachment location is arranged on the additional plate.

9. A device according to claim 8 , wherein the additional plate exceeds the perimeter of the table leg and the attachment location is arranged outside the outer perimeter of the upper end of the table leg.

10. A device according to claim 4 , wherein the piece of furniture is a table adjustable in height, comprising at least one table leg adjustable in height and a table top being directly or indirectly connected to the table leg, and the attachment location is arranged at the table top in close proximity to the upper end region of the table leg.

11. A device according to claim 4 , wherein the piece of furniture is a table adjustable in height, comprising at least one table leg adjustable in height and a table top, the table top is connected to a supporting frame comprising a horizontal supporting plate connected to the table leg, and the attachment location is arranged at the table top opposite to the upper end region of the table leg.

12. A device according to claim 11 , wherein the attachment location is arranged at the supporting plate neighbouring the upper end region of the table leg or opposite to this attachment location at the other side of the supporting plate.

13. A device according to claim 1 , wherein the sensor is adapted to detect an acceleration of a portion of the moveable part instead of a change in bend of the moveable part.

14. A device according to claim 13 , wherein the sensor is arranged at the moveable part at an attachment location, at which a higher than average acceleration is applied in a case of a collision.

15. A device according to claim 14 , wherein the piece of furniture is a table adjustable in height, comprising at least one table leg adjustable in height and a table top with a front edge and a rear edge, and the attachment location is arranged at the front edge or the rear edge.

16. A method for recognizing/handling collisions with automatically moveable parts of furniture with obstacles comprising the steps:

a) providing a piece of furniture that includes:

i) at least one moveable part that is adapted to be moved relatively to the remaining piece of furniture in a non-manual manner,

ii) an automatic driving mechanism adapted to move the moveable part,

iii) a controller adapted to control the automatic driving mechanism, and

iv) a sensor adapted to detect a collision with an obstacle during the movement of the moveable part and to transmit the collision to the controller,

b)driving an automatic driving mechanism by the controller for moving the moveable part in a pre-defined direction,

c) detecting a change in bend or a change in acceleration of an attachment location of the moveable part by a sensor during a collision of the moveable part with an obstacle,

d) transmitting a signal from the sensor to the controller, and

e) stopping the automatic driving mechanism by the controller.

17. A method according to claim 16 wherein step c) consists of:

c 1 ) changing an upsetting or stretching of a piezoelectric material during the change in bend of the attachment location of the moveable part, and

c 2 ) generating an electric signal by the piezoelectric material during the change in upsetting or stretching.

18. A method according claim 17 , wherein step c 2 ) consists of:

changing the bend of a piezoelectric diaphragm.

19. A method according to claim 16 , wherein the detection of the change in bend is carried out at an attachment location comprising a higher than average bending strain during a collision.

20. A method according to claim 16 , wherein the steps follow the step of moving back the moveable part by a pre-defined distance in a. direction opposing the previous moving direction.