Patent ID: 8033075
Filing Date: 2011-10-11
Classification: E04F

Abstract:
1. A locking system for mechanical joining of floor-boards, each of the floorboards comprising a body comprising plywood with several layers; a top layer on one side of the body; a balance layer on a rear side of the body, the rear side opposite the one side; immediately juxtaposed upper parts of two adjacent joint edges of two joined floorboards together define a joint plane perpendicular to a principal plane of the floorboards; said locking system providing a joining of the two joint edges horizontally perpendicular to the joint plane, the locking system comprising: a locking groove which is formed in an underside of and extends in parallel with a first joint edge at a distance from the joint plane, the locking groove having an opening, a bottom, and two side walls; a portion projecting from a lower part of the second joint edge and below the first joint edge and integrated with the body of each floorboard; said projecting portion supporting, at a distance from the joint plane, a locking element for cooperating with the locking groove; said projecting portion being located entirely outside the joint plane as seen from the side of the second joint edge; said projecting portion including an inner part, a central part and an outer part extending in that order from the joint plane, the inner and outer parts comprising at least two layers of the plywood, and the central part being formed only of the balance layer; and a surface of the walls of the locking groove comprises at least two layers of the plywood.