Mechanical locking system for floor panels

1. A set of floor panels which are mechanically connectable to each other along one pair of adjacent edges, so that upper joint edges of said floor panels in a connected state define a vertical joint plane, each of said floor panels comprising:

a flexible tongue on a second edge of the floor panel;

a locking element and a locking strip formed in one piece with the floor panel at a first edge and a locking groove at the opposite second edge, the locking strip being outside of the vertical joint plane beyond the upper joint edge of the first edge, and the locking groove being open towards a rear side of the floor panel that faces a subfloor;

the locking element and the locking groove form a horizontal mechanical connection perpendicular to the vertical joint plane, the locking element having a locking surface that is adapted to directly contact a locking surface of the locking groove for locking the floor panels to each other horizontally parallel to a horizontal plane and at right angles to the joined first and second edges;

the flexible tongue comprising resilient parts formed of a separate material than the core of the floor panels, and cooperates with a part of the locking strip for mechanically locking together said adjacent edges vertically parallel to the vertical joint plane and at right angles to the horizontal plane of the floor panels;

wherein two of the panels can be mechanically joined together by displacement of said two floor panels vertically towards each other, while at least a part of the flexible tongue, comprising a flexible snap tab extending upwards, is resiliently displaced substantially around a center point located at a lower part of the flexible tongue, to an inner position until said adjacent edges of the two floor panels are brought into engagement with each other vertically, and the flexible snap tab is displaced towards its initial position, and a distal end of the flexible snap tab is exposed to the subfloor in the connected state of the floor panels;

wherein the flexible tongue has an inner part mounted in a sideward open holding groove in the second edge that is open towards the vertical joint plane, and the inner part is fixed in the sideward open holding groove.

2. The set of floor panels as claimed in claim 1 , wherein the inner part comprises one or several vertical cross sections and wherein at least one of said vertical cross sections is larger than a thickness of the flexible snap tab and/or another vertical cross section of the inner part.

3. The set of floor panels as claimed in claim 1 , wherein the flexible tongue during locking is bent horizontally along at least one of the adjacent edges.

4. The set of floor panels as claimed in claim 1 , wherein a part of the first edge and the flexible snap tab are configured such that the first contact point between the first edge and the flexible snap tab is located at an upper part of said flexible snap tab when the second edge is displaced along the vertical joint plane towards the first edge.

5. The set of floor panels as claimed in claim 1 , wherein the flexible snap tab during locking is configured to slide against a part of the locking element.

6. The set of floor panels as claimed in claim 5 , wherein the flexible snap tab during locking is configured to slide against an upper part of the locking element.

7. The set of floor panels as claimed in claim 5 , wherein the flexible snap tab during locking is configured to slide against an outer part of the locking element.

8. The set of floor panels as claimed in claim 7 , wherein the outer part of the locking element comprises a bevel.

9. The set of floor panels as claimed in claim 1 , wherein the flexible tongue is made of extruded polymer material.

10. The set of floor panels as claimed in claim 1 , wherein the center point is spaced from a lower part of the sideward open holding groove.

11. The set of floor panels as claimed in claim 1 , wherein an outer part of the flexible snap tab locks against a locking surface formed on an outer part of the locking strip.

12. The set of floor panels as claimed in claim 11 , wherein the locking surface is inclined upwards.

13. The set of floor panels as claimed in claim 11 , wherein the locking surface is inclined downwards.

14. The set of floor panels as claimed in claim 11 , wherein the locking surface is rounded.

15. The set of floor panels as claimed in claim 1 , wherein the sideward open holding groove is inclined against the horizontal plane.

16. The set of floor panels as claimed in claim 1 , wherein the center point is offset horizontally from the sideward open holding groove.

17. The set of floor panels as claimed in claim 1 , wherein at least a part of the flexible tongue is disposed at a rear side of the floor panels.

18. The set of floor panels as claimed in claim 1 , wherein the flexible snap tab locks against a locking surface formed on a lower part of the locking strip.