(19)

(11)

EP 0 741 630 A1

(12)

(43) Date of publication: 13.11.1996 Bulletin 1996/46 (21) Application number: 95906426.0 (22) Date of filing: 25.01.1995

(51) International Patent Classification (IPC):  B24B 19/ 12( . ) (86) International application number: PCT/GB1995/000146 (87) International publication number: WO 1995/020467 (03.08.1995 Gazette 1995/33)

(84) Designated Contracting States: DE ES FR IT (30) Priority: 26.01.1994 GB 19940001462 (71) Applicant: WESTERN ATLAS U.K. LIMITED Aylesbury, Buckinghamshire HP20 2RQ (GB)	(72) Inventors: BARTLETT, Christopher D. West Yorkshire BD20 6SS (GB) MIDGLEY, Clive J. S. Skipton, North Yorkshire BD23 3RE (GB) (74) Representative: Nash, Keith Wilfrid, et al  Pearl Assurance House 90-92 Regent Street Cambridge CB2 1DP Cambridge CB2 1DP (GB)