Patent ID: 6338390
Filing Date: 2002-01-15
Classification: E21B

Abstract:
An earth drilling device for variably contacting an earth formation, comprising:a near bit sub member configured for attachment to the downhole end of a drill string; a bit body attached to said near-bit sub member, said bit body having fixed cutting elements secured thereto and positioned to contact an earth formation; and apparatus associated with said near-bit sub member for producing a variable depth of cut by said fixed cutting elements into said earth formation while said bit body is rotated by said drill string and wherein said apparatus is structured to provide axial movement of said bit body relative to said near-bit sub member to produce a variable depth of cut by said fixed cutting elements into said earth formation during drilling, said apparatus comprising a lower member attached to said bit body and an upper member spaced from said lower member and biased with respect thereto by a resilient member providing movement of said lower member relative to said upper member.