(19)
(11) EP 0 418 101 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
27.12.1991 Bulletin 1991/52

(43) Date of publication A2:
20.03.1991 Bulletin 1991/12

(21) Application number: 90310087.3

(22) Date of filing: 14.09.1990
(51) International Patent Classification (IPC)5: B24B 9/16, B25B 1/22, B28D 7/04
(84) Designated Contracting States:
BE GB NL

(30) Priority: 15.09.1989 ZA 897055

(71) Applicant: DE BEERS INDUSTRIAL DIAMOND DIVISION (PROPRIETARY) LIMITED
Johannesburg, Transvaal (ZA)

(72) Inventors:
  • Segal, Thomas
    Randburg, Transvaal (ZA)
  • Harris, Michael Alexander
    8, Sandton, Transvaal (ZA)
  • Tolkowsky, Gabriel Shrage
    Antwerpen (BE)

(74) Representative: Senior, Alan Murray et al
J.A. KEMP & CO., 14 South Square, Gray's Inn
London WC1R 5LX
London WC1R 5LX (GB)


(56) References cited: : 
   
       


    (54) Dop


    (57) The dop has a body (10) and a jaw assembly (12) that has two opposed, adjustably spaced jaws (58). The jaws (58) of the jaw assembly (12) are used to grip a gemstone (69) between them for polishing purposes. The body (10) is attached to a supporting structure and the jaws (58) can be pivoted relative to the body (10), to bring the stone (69) to the desired orientation, about two mutually orthogonal axes. Such pivotal movement is achieved using worm gear mechanisms (28,30; 48,50) which lead to accurate orientation of the stone (69).







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