Mechanical locking system for floor panels

1. Building panels provided with a locking system for vertical and horizontal locking of a first edge and a second edge of adjacent building panels, said locking system comprising:

a displaceable tongue at least partly arranged in a displacement groove,

a tongue groove,

a cavity provided in a strip at the first edge, and

a protrusion extending downwards at the second edge,

wherein the displaceable tongue is arranged to be displaced at least partly into the tongue groove during locking, and

wherein the protrusion is arranged to be located in at least a portion of the cavity when the building panels are locked vertically and horizontally,

wherein the cavity extends entirely through the strip.

2. The building panels according to claim 1 , wherein the displacement groove is arranged in the first edge and the tongue groove is arranged in the second edge.

3. The building panels according to claim 1 , wherein the displacement groove is arranged in the second edge and the tongue groove is arranged in the first edge.

4. The building panels according to claim 1 , wherein the displaceable tongue is arranged to snap into the tongue groove during locking.

5. The building panels according to claim 1 , wherein the displaceable tongue is flexible.

6. The building panels according to claim 1 , wherein the displaceable tongue is a separate part of the building panels.

7. The building panels according to claim 1 , wherein the displaceable tongue is arranged to first be displaced at least partly into the displacement groove and then at least partly into the tongue groove during locking.

8. The building panels according to claim 1 , wherein the displacement groove extends horizontally.

9. The building panels according to claim 1 , wherein the displacement groove is provided above the strip when the building panels are locked vertically and horizontally.

10. The building panels according to claim 1 , wherein a lower part of the displacement groove is located in a same horizontal plane as an upper part of the strip when the building panels are locked vertically and horizontally.

11. The building panels according to claim 1 , wherein the displaceable tongue comprises an inner flexible part.

12. The building panels according to claim 1 , wherein the strip comprises a locking element arranged to cooperate with a downwardly open locking groove formed in the second edge for horizontal locking.

13. The building panels according to claim 12 , wherein the locking element extends continuously along the first edge.

14. The building panels according to claim 1 , wherein a thickness of the strip outside of the cavity is equal to the thickness of the strip inside of the cavity.

15. The building panels according to claim 1 , wherein a thickness of the strip outside of the cavity is larger than the thickness of the strip inside of the cavity.

16. The building panels according to claim 1 , wherein the tongue groove is provided above the strip when the building panels are locked vertically and horizontally.

17. The building panels according to claim 1 , wherein a lower part of the tongue groove is located in a same horizontal plane as an upper part of the strip when the building panels are locked vertically and horizontally.

18. The building panels according to claim 1 , wherein said locking system comprises:

a plurality of cavities provided in the strip, and

a plurality of protrusions extending downwards at the second edge,

wherein each protrusion is arranged to be located in at least a portion of a corresponding cavity when the building panels are locked vertically and horizontally.

19. The building panels according to claim 1 , wherein the building panels are configured to be locked by a vertical displacement of a second building panel relative to a first building panel.