(19)
(11) EP 0 738 823 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
05.11.1997 Bulletin 1997/45

(43) Date of publication A2:
23.10.1996 Bulletin 1996/43

(21) Application number: 96302709.9

(22) Date of filing: 18.04.1996
(51) International Patent Classification (IPC)6: E21B 10/56
(84) Designated Contracting States:
BE DE FR IE

(30) Priority: 22.04.1995 GB 9508226

(71) Applicant: CAMCO DRILLING GROUP LIMITED
Stonehouse, Gloucestershire GL10 3RQ (GB)

(72) Inventors:
  • Matthias, Terry R.
    Gloucestershire (GB)
  • Newton, Alex
    Texas, TX 77067 (US)

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

   


(54) Improvements in or relating to elements faced with superhard material


(57) A preform element, such as a cutting element for a rotary drag-type drill bit, includes a facing table (20) of superhard material having a front face (23), a peripheral surface(29), and a rear surface (27) bonded to a substrate (21) which is less hard than the superhard material. The rear surface (27) of the facing table is integrally formed with a plurality of ribs (25, 26) which project into the substrate (21), and at least major portions of the ribs extend across the rear surface of the facing table in directions which are generally radial with respect to at least one point (28) which is adjacent or outside the peripheral surface (29) of the facing table.






Search report