(19)
(11) EP 0 154 936 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
11.06.1986 Bulletin 1986/24

(43) Date of publication A2:
18.09.1985 Bulletin 1985/38

(21) Application number: 85102568

(22) Date of filing: 07.03.1985
(84) Designated Contracting States:
BE DE FR GB

(30) Priority: 16.03.1984 US 590366

(71) Applicant: Norton Christensen, Inc.
 ()

(72) Inventors:
  • Carroll, Jimmy L.
     ()
  • Grappendorf, Richard H.
     ()
  • Meskin, Alexander K.
     ()

   


(54) An exposed polycrystalline diamond mounted in a matrix body drill bit


(57) A polycrystalline diamond body (10) is securely retained on the surface (17) of a matric body bit (11) while being substantially exposed and unsupported above the matrix surface (18) by partial, unsupported disposition of the diamond body (10) below the surface (20) of the matrix material (18) in such a manner that at least two locking points (26) on the diamond body (10) and between the diamond body (10) and matrix material (18) are established. More particularly, depending upon the geometric shape of the diamond body (10), the diamond body (10) is disposed within the matrix material (18) and extends above the surface (20) of the matrix material (18) by at least 50% of the volume of the diamond (10) and at an orientation such that one or more sides or surfaces (14) of the diamond body (10) are inclined with respect to the normal to the surface (20) of the matrix material (18), so that when the matrix material (18) is molded about the inclined surfaces (14) of the diamond body (10) a locking wedge is formed thereover.






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