Mechanical locking system for floor panels

1. A new floor panel comprising connectors which are integrated with the new floor panel and adapted to connect the new floor panel to essentially identical first and second floor panels, so that upper joint edges of said new and second floor panels in the connected state define a vertical plane,

said connectors being designed to connect said new floor panel with said second floor panel in a horizontal direction perpendicular to said vertical plane and in a vertical direction parallel to the vertical plane,

one of the connectors for making a vertical connection comprises a flexible tongue in a sliding groove in one of the new or second floor panels,

the sliding groove is formed in an edge of the panel and is open towards the vertical plane,

the flexible tongue has a length direction along a lengthwise direction of the joint edges, a width in the horizontal plane perpendicular to the length and a thickness in the vertical direction,

the flexible tongue is designed to cooperate, in a connected state with a tongue groove of the other of the new or second floor panels,

another one of the connectors for making a horizontal connection comprises a locking strip which projects from said vertical plane in the second panel and carries a locking element,

said locking strip is designed to cooperate, in a connected state, with a downward open locking groove of the new floor panel,

wherein the new floor panel is adapted to be locked to the first and second floor panels with vertical folding,

the flexible tongue during the vertical folding is capable of being displaced two times in the sliding groove,

a first displacement is effected by the vertical folding of the new floor panel whereby at least a part of the flexible tongue is capable of being bent in the horizontal direction,

a second displacement of the flexible tongue towards its initial position is accomplished substantially by a spring effect caused by said bending of said flexible tongue,

wherein the flexible tongue along its length has a middle section and two edge sections on both sides of the middle section and that the middle section could be displaced more than one of the edge sections.

2. The floor panel as claimed in claim 1 , wherein said flexible tongue has a projecting portion which in connected state is located outside the sliding groove and a groove portion in the sliding groove such that the size of said projecting portion and/or the groove portion varies along the length.

3. The floor panel as claimed in claim 1 , wherein said flexible tongue has a projecting portion which in connected state is located outside the sliding groove and a groove portion in the sliding groove such that the size of said projecting portion and/or the groove portion varies along the length.

4. The floor panel as claimed in claim 1 , wherein said flexible tongue has a projecting portion which in connected state is located outside the sliding groove and a groove portion in the sliding groove such that the size of said projecting portion and/or the groove portion varies along the length.

5. The floor panel as claimed in claim 2 , wherein the projecting portion is spaced from a corner section of the panel.

6. The floor panel as claimed in claim 1 , wherein the flexible tongue is made of moulded polymer material.

7. The floor panel as claimed in claim 5 , wherein the flexible tongue is made of moulded polymer material.

8. The floor panel as claimed in claim 5 , wherein the dimensions of the new and second panels are such that the locking element is partly in the locking groove when the first displacement starts.

9. The floor panel as claimed in claim 8 , wherein the flexible tongue is on the same edge as the locking strip.

10. A floor panel comprising an edge portion presenting a sidewardly open groove, in which a tongue formed as a separate part is received, the tongue is bendable in a plane substantially parallel with a main plane of the floor panel, such that the tongue is resiliently displaceable in said plane,

wherein the flexible tongue has a length direction along a lengthwise direction of the edge portion, a width in a horizontal plane perpendicular to the length and a thickness in a vertical direction,

wherein the flexible tongue is adapted to bend such that it capable of displacing along its length direction, wherein the tongue's length direction is greater than its width direction.

11. The floor panel of claim 10 , wherein the tongue during a vertical folding is capable of being displaced two times in the sidewardly open groove,

a first displacement is effected by the vertical folding of the floor panel whereby at least a part of the tongue is capable of being bent in the horizontal direction,

a second displacement of the tongue towards its initial position is accomplished substantially by a spring effect caused by said bending of said tongue,

wherein the tongue along its length has at least two sections and that the first or second displacement of one of the sections is larger than the first or second displacement of the other one of the sections.

12. The floor panel as claimed in claim 11 , wherein the flexible tongue along its length has a middle section and two edge sections on both sides of the middle section and that the middle section could be displaced more than one of the edge sections.

13. The floor panel as claimed in claim 12 , wherein said flexible tongue has a projecting portion which in connected state is located outside the sliding groove and a groove portion in the sliding groove such that the size of said projecting portion and/or the groove portion varies along the length.