Mechanical locking system for floor panels

A set of essentially identical floor panels provided with a mechanical locking system comprising a strip extending horizontally from a lower part of a first edge and a downwardly open locking groove formed in an adjacent second edge,

• the strip comprising an upwardly protruding locking element which is configured to cooperate with the locking groove for locking the first edge and the second edge in a horizontal direction parallel to a main plane of the panels and in a vertical direction being perpendicular to the horizontal direction, wherein the locking element and the locking groove comprise an upper locking surface and a lower locking surface which are configured to lock the panels vertically,
• wherein the upper locking surface is located in an upper part of the locking element facing an upper edge of the first panel,
• wherein the first edge includes an upper part, and a middle part between the upper part and the lower part,
• wherein the upper part extends further than the middle part horizontally toward the adjacent second edge,
• wherein the upper locking surface is inclined or rounded and extends from the locking element and towards an inner part of the panel such that a tangent line TL to the upper locking surface of the locking element intersects the first edge at the upper part of the first edge, and
• wherein a tangent line to the lower locking surface of the locking groove intersects the first edge at the upper part of the first edge in a locked state of the mechanical locking system.