Patent ID: 8171692

Claim:
A flooring system, comprising a plurality of rectangular floor panels adapted to be installed on a sub floor, said floor panels having long and short edges which are connectable to each other along one pair of adjacent edges of adjacent panels having a mechanical locking system comprising a tongue formed in one piece with the panels and a groove for mechanically locking together said adjacent edges at right angles to the horizontal plane of the panels, thereby forming a vertical mechanical connection between the panels, the mechanical locking system being designed for connecting adjacent panels by inward angling to a locked position, and a locking element at one first edge and a locking groove at an opposite second edge thereby forming a first horizontal mechanical connection locking the panels to each other in a direction parallel to the horizontal plane and at right angle to the joint edges, wherein: each panel at said adjacent edges being provided with a second horizontal mechanical connection locking the panels to each other along the joint edges, in a direction parallel to the horizontal plane and parallel to the joint edges, when the panels are laying flat on the sub floor, said second horizontal mechanical connection comprises a plurality of small local protrusions in said mechanical locking system which prevents displacement in both directions along the joint edges when the panels are laying flat on the sub floor and are locked with the vertical and the first horizontal connections.