US Patent 7849655 Connecting system for surface coverings

A system and method for joining floor planks includes two or more planks wherein each plank includes a tongue, a groove, and optionally a shoulder, and optionally a protruding lip, that provide a mechanism for connecting two or more planks together. The tongue can be on the opposing side of each plank from the groove. The groove can be defined between a first flange extending along a first edge of the plank and from one side of the plank, and a second flange extending distally beyond a distal edge of the first flange from the first edge of the plank and from a second side of the plank opposite from the first side. The tongue can be S-shaped to form an interlocking relationship with the groove.