Mechanical locking system for floor panels

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

• a flexible tongue on a first edge of a floor panel;
• a tongue groove on an opposite second edge of the floor panel for receiving the flexible tongue of an adjacent floor panel for mechanically locking together said first and second edges vertically parallel to the vertical joint plane and at a right angle to a horizontal plane of the floor panels, wherein the tongue groove is formed in a core of the floor panel and is open towards the vertical joint plane;
• and
• a locking element formed in one piece with the floor panel at the first edge and a locking groove at the opposite second edge, the locking groove being open towards a rear side of the floor panel that faces a subfloor,
• wherein 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 configured to directly contact a locking surface of the locking groove for locking the floor panels to each other horizontally parallel to the horizontal plane and at a right angle to the joined first and second edges;
• wherein the flexible tongue comprising an upper resilient part formed of a separate material than the core of the floor panel, and cooperates with a locking surface in the tongue groove;
• wherein the upper resilient part is displaceable in a displacement groove;
• wherein a lower part of the flexible tongue is connectable in a fixed manner in a holding groove at the first edge, the holding groove including a top wall, a bottom wall, and a side wall connecting the top wall to the bottom wall, and at least the top wall is vertically below the displacement groove,
• wherein two of the floor panels are configured to be mechanically joined together by displacement of said two floor panels vertically towards each other while the upper resilient part is resiliently displaced inwardly from an initial position, which is outside the vertical joint plane, to an inner position toward the first edge until said adjacent edges of the two floor panels are brought into engagement with each other vertically, and the upper resilient part is displaced towards its initial position away from the vertical joint plane and against the tongue groove.