EP 0225101 A2 19870610 - Improvements in or relating to drill bits.
Title (en)
Improvements in or relating to drill bits.
Title (de)
Bohrmeissel.
Title (fr)
Trépan de forage.
Publication
Application
Priority
GB 8528894 A 19851123
Abstract (en)
A rotary drill bit for drilling deep holes in subsurface formations comprises a bit body (10) having a shank for connection to a drill string and a plurality of elements (16,22) mounted on the bit body (10) for cutting, abrading or bearing on the formation being drilled. The bit body (10) includes a fixed structure (11) and a movable structure (17), each carrying elements (16,22) for acting on the formation, the movable structure (17) being capable of reversible movement relatively to the fixed structure (11) between two limiting positions, the relative movement providing at least two configurations in which there are different distributions, between said elements (16,22), of the loads applied to the bit during its engagement with the formation. Control means, such as hydraulic means (29,30), are provided to control the movement of the movable structure (17), and hence the load distribution between the elements (16,22), automatically in response to the torque and/or axial loads applied to the bit.
IPC 1-7
IPC 8 full level
E21B 10/56 (2006.01); E21B 10/567 (2006.01); E21B 10/62 (2006.01)
CPC (source: EP US)
E21B 10/14 (2013.01 - EP); E21B 10/62 (2013.01 - EP US)
Designated contracting state (EPC)
BE CH DE FR LI NL SE
DOCDB simple family (publication)
EP 0225101 A2 19870610; EP 0225101 A3 19880921; AU 6538886 A 19870528; GB 2183694 A 19870610; GB 8528894 D0 19860102; GB 8627439 D0 19861217
DOCDB simple family (application)
EP 86308956 A 19861117; AU 6538886 A 19861119; GB 8528894 A 19851123; GB 8627439 A 19861117