(19)
(11) EP 0 299 692 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
23.11.1989 Bulletin 1989/47

(43) Date of publication A2:
18.01.1989 Bulletin 1989/03

(21) Application number: 88306285.3

(22) Date of filing: 08.07.1988
(51) International Patent Classification (IPC)4: B24B 9/16, B24B 37/04, B24B 41/04
(84) Designated Contracting States:
BE DE FR LU NL

(30) Priority: 14.07.1987 GB 8716512

(71) Applicant: GERSAN ESTABLISHMENT
FL-9490 Vaduz (LI)

(72) Inventor:
  • Blondeel, Eric Joseph
    B-8200 Brugge (BE)

(74) Representative: Lyndon-Stanford, Edward Willoughby Brooke et al
MARKS & CLERK, 57/60 Lincoln's Inn Fields
London WC2A 3LS
London WC2A 3LS (GB)


(56) References cited: : 
   
       


    (54) Gemstone polishing apparatus


    (57) In order to centre the residual imbalance of a scaife (5), the scaife (5) is carried on an air bearing (6) which is axially stiff but allows radial float, and is driven by a motor (2) which is carried on silent blocks (3) which are axially stiff but allow radial float of the motor (2). The motor (2) is driven at a speed above the first radial critical frequency of the system formed by the motor (2), motor shaft (4) and scaife (5) and its mounting.







    Search report