Rotary drill bit with rotary cutters

US4258806A · kind A · utility

Assignees

• SANDVIK AB · SE
• AKTIEBOLAGET SKF · SE

Inventors

• Heinrich Kunkel · Schweinfurt, DE
• Armin Olschewski · Schweinfurt, DE
• Manfred Brandenstein · Aschfeld, DE
• Lothar Walter · Schweinfurt, DE
• Horst M. Ernst · Eltingshausen, DE

Key dates

• Filing date: May 29, 1979
• Grant date: Mar 31, 1981
• Expiry date: May 29, 1999

Classification

• Technology area (CPC E): Fixed Constructions
• CPC primary: E21B10/20
• WIPO field: Civil engineering
• WIPO sector: Other fields

Abstract

A rotary drill bit having a drill bit body and at least one trunnion projecting from the drill bit body and a rotary cutter supported on at least one pair of radial rolling bearings on the trunnion. The rolling elements of at least one bearing are guided on at last one axial end facing the drill bit body in an outer bearing race groove incorporated in the bore of the rotary cutter. The inner bearing groove is formed on the trunnion for the rolling elements of the radial roller bearing. A filling opening is provided for assembly of the rolling elements comprising a channel which extends through the drill bit body and trunnion and is essentially axially oriented having one terminal end adjacent the inner bearing race groove and at least one filler piece for sealing the opening. The filling opening is arranged to provide a common filling means for each radial bearing.