US Patent 9874027 Mechanical locking system for floor panels

Floor panels are shown, which are provided with a vertical locking system on short edges comprising a displaceable tongue that is displaced in one direction into a tongue groove during vertical displacement of two panels. The displaceable tongue may be provided in a sidewardly open displacement groove at an edge of a building panel, the displaceable tongue including a main body extending along the edge of the panel and a tongue locking surface located at an upper and outer part of the tongue.