Drill bit
CA 2056049 C · Owner: Stewart, Aulette · Inventors: Stewart, Aulette
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A rotatable crown for a rotary drill bit comprises a working end which presents a working face for the crown and an opposite end for engagement with a drill rod stringer or adaptor coupling. The working end comprises a mass of discrete abrasive particles uniformly distributed through a bonding matrix and a plurality, of elongate abrasive elements so arranged in the matrix that ends thereof are located in the working face. The working face has a serrated profile with alternating peaks and troughs. The ends of the elongate elements are located in peaks.
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 November 22, 1991 and granted February 24, 1998. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 22, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 22, 2013.
- 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.