Patent ID: 7299887
Filing Date: 2007-11-27
Classification: E21B

Abstract:
1. A single cone bit with offset axis and composite cones, the single cone bit comprising: a head body and a cone; a head journal at lower end of the head body for rotatablely connection with the cone; said cone section having a shape of composite cones, wherein the outer circumference of the cone is composed of from a back face of the cone to a top of the cone an extended gage surface, an outer cone surface and a main cone surface, forming the cone section in a shape of composite cones, a plurality of cutting elements mounted onto each cone surface, the said main cone surface having a negative cone surface, and an angle ε formed by generatrix of the main cone surface and centerline of the cone rotation being equal to or less than 90° (i.e.ε≦90°), the axis of the bit being offset from the axis of the cone and head journal, wherein; a gage pad arranged on a side of head body opposite to the offset direction of the head journal, the opposite side of the gage pad provided with the junk slots, and jet ports arranged at a lower bevel of the head body.