A drill bit comprises a bit body having a plurality of upstanding main blades formed thereon. The main blades have a plurality cutting elements mounted thereon, and they are shaped such that a cutting profile of the bit includes a nose portion, an inner cone region located radially inwards of the nose...http://www.google.es/patents/US20060260845?utm_source=gb-gplus-sharePatente US20060260845 - Stable Rotary Drill Bit
