(19)
(11) EP 0 955 446 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
16.08.2000 Bulletin 2000/33

(43) Date of publication A2:
10.11.1999 Bulletin 1999/45

(21) Application number: 99303483.4

(22) Date of filing: 04.05.1999
(51) International Patent Classification (IPC)7: E21B 10/56, B23P 15/28, B23B 27/14
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 08.05.1998 GB 9809690

(71) Applicant: Camco International (UK) Limited
Stonehouse, Gloucestershire GL10 3RQ (GB)

(72) Inventor:
  • Griffin, Nigel Dennis
    Whitminster, Gloucestershire (GB)

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

   


(54) Preform cutting element


(57) A preform cutting element, for use in a drag-type drill bit, includes a facing table (10) of polycrystalline diamond having a front face (12), a peripheral surface (13), and a rear surface (14) bonded to the front face of a tungsten carbide substrate (11). The rear face (14) ofthe diamond facing table is integrally formed with a single protuberance (19), adjacent the periphery ofthe element, which extends into a correspondingly shaped recess in the substrate (11).






Search report