Patent ID: 6394725
Filing Date: 2002-05-28
Classification: F16B

Abstract:
A countersunk head screw comprising:a head; a shank, said head and said shank extending along a longitudinal axis of said screw; a screw thread extending at least partially over said shank; said head comprising: a top portion that is generally perpendicular to said longitudinal axis; a bearing surface that generally tapers inwardly from said top portion toward said shank, said bearing surface having an upper region adjacent to said top portion and a lower region adjacent to said shank, said upper region extending a first distance along said bearing surface; and at least one restraint rib projecting from said upper region of said bearing surface, said at least one restraint rib comprising opposing lateral faces of convex shape adjoining each other at an edge, said edge being centered relative to said opposing lateral faces, said rib extending a second distance along said upper region of bearing surface, said second distance being not greater than said first distance; and wherein said at least one restraint rib increases the frictional resistance of said head to rotation in either direction about said longitudinal axis of said screw without removing material from a substrate to which said screw is applied.