Core cutting rock bit
CA 2129559 C · Owner: Smith International, Inc. · Inventors: Tyner, Gilbert S.; Johns, Roger P.; Portwood, Gary
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A roller cone drill bit is disclosed that leaves uncut a formation core having a diameter from 10% to 25% of the bit gage diameter. Cutters in circumferential rows away from the apex of the cones extend a sufficient distance closer to the centerline of the rock bit than the core cutters at the apex of a cone for breaking the central core. The bit is designed to have normal sizebearings cone shell thickness and cutter protrusion to allow the use of standard drilling weights and rotary speeds, thereby achieving a significant increase in drilling rate. When drilling abrasive formations ultra hard cutting teeth are used, in the cone apex to maintain the core diameter.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed August 5, 1994 and granted July 21, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 5, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 5, 2016.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.