Patent · US Expired

Direct drill bit drive

US4388973A · kind A · utility

16Cited by

6References

8Claims

0Family size

Assignee

Zahnradfabrik Friedrichshafen AG · DE

Inventors

Siegfried Winkelmann · Tettnang, DE
Horst Schulz · Friedrichshafen, DE

Key dates

Filing date	Mar 31, 1981
Grant date	Jun 21, 1983
Priority date	—
Expiry date	Mar 31, 2001

Classification

Technology area (CPC E)Fixed Constructions
CPC primaryE21B4/003
WIPO fieldCivil engineering
WIPO sectorOther fields

Abstract

A direct drive for a drill bit in a drill string has a fluid-operated motor within a drive section connected by a gear section to a bearing section whose inner tube is coupled to the drill bit to accommodate axial displacement of the drill bit within the outer tube, spring elements are braced against a radial bearing for the inner tube which has at least one axially defined race. The coupling between the inner tube and the gearing also accommodates such axial displacement and a reservoir for oil is located between the drive and gear sections so that oil can be fed to the gearing, the bearings and to an axial bearing in an annular oil-filled space between the drive and gear sections.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.