Method of designing a roller cone bit

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(11)

EP 1 500 783 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	12.04.2006 Bulletin 2006/15

(43)	Date of publication A2:
	26.01.2005 Bulletin 2005/04

(21)	Application number: 04025562.2

(22)	Date of filing: 31.08.1999

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International Patent Classification (IPC):

(84)	Designated Contracting States:
	GB IT

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Priority:

31.08.1998 US 98442 P

(62)	Application number of the earlier application in accordance with Art. 76 EPC:
	03021139.5 / 1371811
	99945376.4 / 1117894

(71)	Applicant: HALLIBURTON ENERGY SERVICES, INC.
	Carrollton, TX 75006 (US)

(72)	Inventor:
	Chen, Shilin Dallas, TX 75248 (US)

(74)	Representative: HOFFMANN EITLE
	Patent- und Rechtsanwälte Arabellastrasse 4 81925 München 81925 München (DE)

(54)	Method of designing a roller cone bit

(57) Disclosed herein is a method of designing a roller cone bit, comprising the steps of:

Calculating the trajectory of at least one tooth on each cone through formation material at the cutting face; and

Jointing optimising both the orientations of said teeth and the width of uncut rings on said cutting face, in dependence on said trajectory.