Cutting structure and rotary drill bit comprising such a structure

(19)

(11)

EP 0 291 314 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	20.09.1989 Bulletin 1989/38

(43)	Date of publication A2:
	17.11.1988 Bulletin 1988/46

(21)	Application number: 88304325.9

(22)	Date of filing: 12.05.1988

(51)	International Patent Classification (IPC)⁴: E21B 10/56, B22F 7/06

(84)	Designated Contracting States:
	BE CH DE FR GB LI NL SE

(30)

Priority:

13.05.1987 GB 8711255

(71)	Applicant: Reed Tool Company Limited
	Newtownabbey County Antrim Northern Ireland (GB)

(72)	Inventors:
	Barr, John Denzil Cheltenham (GB) Taylor, Malcolm Roy Gloucester (GB) Matthias, Terry Richard Longlevens Gloucester (GB) Wardley, Michael Thomas Stroud Gloucestershire (GB) Regan, Michael Colin Robinswood Gloucester (GB)

(74)	Representative: Carter, Gerald et al
	Arthur R. Davies & Co. 27 Imperial Square Cheltenham, Gloucestershire GL50 1RQ Cheltenham, Gloucestershire GL50 1RQ (GB)

(56)

References cited: :

(54)	Cutting structure and rotary drill bit comprising such a structure

(57) A cutting structure, for use in a rotary drill bit for drilling or coring holes in subsurface formations, comprises an elongate stud 17 of hard material, such as cemented tungsten carbide, there being at least partly embedded in the stud, at one end thereof, one or more thermally stable polycrystalline diamond cutting elements 14, 15, 16. The diamond elements, which may be in the form of small rectangular blocks or cylinders, are bonded into the stud by a hot pressing or an infiltration process.

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