Mechanical locking system for floor panels

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 the connected state define a vertical plane, each of said floor panels comprising:

• a flexible tongue on a first edge of the panel;
• a tongue groove on a second opposite edge of the panel for receiving the flexible tongue of an adjacent panel for mechanically locking together said adjacent edges vertically parallel to the vertical plane and at right angles to a horizontal plane of the panels;
• the tongue groove is formed in a core of the panel and is open towards the vertical plane;
• a locking element formed in one piece with the 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 panel that faces a subfloor;
• the locking element and the locking groove form a horizontal mechanical connection perpendicular to the vertical plane, the locking element having a locking surface that is adapted to directly contact a locking surface of the locking groove for locking the panels to each other horizontally parallel to the 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, and cooperates with a locking surface in the tongue groove;
• wherein two of the panels can be mechanically joined together by displacement of said two panels vertically towards each other, while at least an outer part of the flexible tongue, comprising a flexible snap tab extending downwards, is resiliently displaced inwardly to an inner position which is outside the vertical plane until said adjacent edges of the two panels are brought into engagement with each other vertically and the flexible snap tab is displaced towards its initial position away from the vertical plane and against the tongue groove, and
• wherein the flexible tongue has an inner part mounted in a sideward open holding groove in the first edge that is open towards the vertical plane, the inner part is fixed in the sideward open holding groove,
• wherein the flexible snap tab has a cross section with a maximum thickness, and an edge of the locking surface closest to the vertical plane being offset in relation to the vertical plane by at least the maximum thickness of the flexible snap tab and,
• wherein the inner part comprises one or several vertical cross sections and wherein at least one of said vertical cross sections is larger than said thickness of the flexible snap tab and/or another vertical cross section in the inner part.