Down-the-hole drill
CA 2085425 C · Owner: Ekwall, Berndt · Inventors: Jakobsson, Torbjorn; Peterson, Martin; Ekwall, Berndt
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Down-the-hole drill comprising a housing (1) a hammer piston (6), movable to-and-fro in the housing and intended for impacting a drill bit (5). A back piece (3) provided with an extension (12) with a valve part (17) cooperates with a part (8) of a central channel in the hammer piston. This part of the central channel comprises a zone (16) with larger diameter than adjacent parts at an intermediate part of this part. This results in that pressure medium can pass the valve part when it is situated at the zone and that the valve part and the hammer piston sealingly cooperate when the valve part is on either side of the zone.
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 December 15, 1992 and granted July 15, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 15, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 15, 2014.
- 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.