Mechanical locking system for panels and method of installing same

A set of panels which are mechanically connectable to each other along one pair of adjacent edges, each of said panels comprising:

• a flexible tongue on a first edge of the panel;
• a tongue groove on an opposite second edge of the panel for receiving the flexible tongue of an adjacent panel for mechanically locking together said adjacent edges at right angles to a principal plane of the panels thereby forming a vertical mechanical connection between the panels;
• and
• 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;
• wherein the tongue groove is formed in a core of the panel,
• wherein the locking element and the locking groove form a horizontal mechanical connection for locking the panels to each other horizontally parallel to the principal plane and at right angles to the joined first and second edges,
• wherein the flexible tongue being resilient and formed of a separate material than the core, and cooperates with 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 a part of the flexible tongue is resiliently displaced horizontally until said adjacent edges of the two panels are brought into engagement with each other vertically and the tongue is then displaced towards an initial position of the tongue against the tongue groove,
• wherein the flexible tongue has an inner part mounted in a sideward open groove in the first edge and a protruding part, wherein the inner part is fixed in the sideward open groove, and wherein the part of the tongue which is resiliently displaced is the protruding part,
• wherein the uppermost part of the flexible tongue is within the sideward open groove.