Patent ID: 6769218
Filing Date: 2004-08-03
Classification: E04F

Abstract:
A locking system for mechanical joining of floorboards at a joint plane, said floorboards having a core, a front side, a rear side and opposite joint edge portions, of which one is formed as a tongue groove, which is defined by upper and lower lips and has a bottom end, and the other is formed as a tongue with an upwardly directed portion at its free outer end, the tongue groove, seen from the joint plane, having the shape of an undercut groove with an opening, an inner portion and an inner locking surface, and at least parts of the lower lip being formed integrally with the core of the floorboard, and the tongue having a locking surface which is formed to coact with the inner locking surface in the tongue groove of an adjoining floorboard, when two such floorboards are mechanically joined, so that their front sides are positioned in the same surface plane and meet at the joint plane directed perpendicular thereto,wherein the inner locking surface of the tongue groove is formed on the upper lip within the undercut portion of the tongue groove for coaction with the corresponding locking surface of the tongue, said locking surface being formed on the upwardly directed portion of the tongue to counteract pulling-apart of two mechanically joined boards in a direction perpendicular to the joint plane, the lower lip has a supporting surface for coaction with a corresponding supporting surface on the tongue, said supporting surfaces being intended to coact to counteract a relative displacement of two mechanically joined boards in a direction perpendicular to the surface plane, all parts of the portions of the lower lip which are connected with the core, seen from the point where the surface plane and the joint plane intersect, are located outside a plane which is positioned further away from said point than a locking plane which is parallel therewith and which is tangent to the coacting locking surfaces of the tongue groove and the tongue where these are most inclined relative to the surface plane and all parts of the portions of the lower lip which are connected with the core are shorter than the upper lip and terminate at a distance from the joint plane, the lower lip is flexible, and the upper and lower lips of the joint edge portions are formed to enable connection of a laid floorboard with a new floorboard by a pushing-together motion essentially parallel with the surface plane of the laid floorboard for snapping together the parts of the locking system during downward bending of the lower lip of the tongue groove.