(19)
(11) EP 0 326 176 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
21.03.1990 Bulletin 1990/12

(43) Date of publication A2:
02.08.1989 Bulletin 1989/31

(21) Application number: 89101527.3

(22) Date of filing: 30.01.1989
(51) International Patent Classification (IPC)4: E21B 10/46
(84) Designated Contracting States:
BE DE FR GB NL

(30) Priority: 28.01.1988 US 149374

(71) Applicant: NORTON CHRISTENSEN, INC.
Salt Lake City Utah 84119 (US)

(72) Inventors:
  • Anthon, Royce A.
    West Jordan Utah, 84088 (US)
  • Fox, DeWayne C.
    West Jordan Utah, 84084 (US)

(74) Representative: Busse & Busse Patentanwälte 
Postfach 12 26
49002 Osnabrück
49002 Osnabrück (DE)


(56) References cited: : 
   
       


    (54) Reinforced rotary drill bit


    (57) A rotary drill bit (10) for boring earth formations is provided which includes a main body portion of a hard metal matrix material and at least one protrusion (24) or shoulder formed of the same matrix material. On the protrus-ion (24) is mounted a cutting element (22). Means for reinforcing (32) the protrusion (24) are provided and extend between the main body portion of the bit and the protrusion (24). The reinforcements (32) add impact strength to the bit and increase the resistance of the bit to cracking in areas supporting the cutting element (22).







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