Mechanical locking system for floor panels

Building panels provided with a locking system for vertical locking of a first building panel and a second building panel by a vertical displacement of the building panels relative each other, the building panels comprising:

• a sidewardly open tongue groove provided at an edge of the first building panel, and a strip protruding below the tongue groove and outwardly beyond an upper part of the edge of said first building panel;
• the strip comprising a locking element with a locking surface configured to cooperate with a downwardly open locking groove formed on the second building panel, for locking of the first and the second building panels in a horizontal direction;
• a displaceable tongue provided in a sidewardly open displacement groove before locking of the first building panel to the second building panel, the sidewardly open displacement groove being provided in an edge of the second building panel, wherein the displaceable tongue comprises a main body extending along the edge of the second building panel and a tongue locking surface located at an upper and outer part of the main body of the tongue, the tongue locking surface being configured to cooperate with a groove locking surface of the tongue groove for vertical locking;
• wherein the displaceable tongue comprises a protrusion spaced inwardly from an upper part of the edge of said second building panel;
• wherein the protrusion comprises a tongue pressing surface configured to cooperate with a strip pressing surface on the locking surface of the locking element, the displaceable tongue and locking element being configured such that in response to the locking element being inserted into the downwardly open locking groove the tongue pressing surface is vertically displaced and the displaceable tongue is displaced into the tongue groove to obtain a locking of the first and the second building panel in a vertical direction;
• wherein the tongue pressing surface is provided on the protrusion and the strip pressing surface is provided on the locking surface of the locking element;
• and
• wherein the second building panel comprises a cavity for housing the protrusion, and the cavity extends from the displacement groove into the locking groove.