Patent ID: 7690697
Filing Date: 2010-04-06
Classification: E21B,F16L

Abstract:
1. A thread form for making a threaded pipe connection capable of being screwed together and subsequently unscrewed, the thread form comprising: a pin end having external threads with stab flanks and load flanks and flat crests and roots for mating with the mating internal threads of a box end to make up a pipe connection, wherein the load flanks of the external threads are each made up of two facets and three radii, and wherein the stab flanks of the external threads each has irregular flank features, the irregular features comprising three facets and four radii for each of the stab flanks; wherein the facets on the load flanks of the pin end comprise a radially outermost facet which lies in a parallel plane to a radially outermost facet on the stab flanks when viewed in cross section, and wherein the load flanks have a next radially inward facet which lies in a parallel plane to a next radially inward facet on the stab flanks, the stab flanks also having a further radially inward facet; and wherein the threads on the pin end have a given thread height measured between the thread crests and thread roots and wherein each of the various facets on the stab and load flanks has a radial height measured in the same direction as the thread height the combined facet heights defining a stab flank height on one side of the thread and a load flank height on an opposite side of the thread, and wherein the stab flank height is greater than the load flank height.