Stuffing box
CA 2028555 C · Owner: Newton, Hille · Inventors: Newton, Hille
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An improvement in a stuffing box for a rotary polished rod having a tubular housing with rod guides disposed at each end. The improvement consists of a second rod guide disposed in a passage at a second end of the tubular housing. The second rod guide is in the form of an annular bushing having a first end, a second end, an external surface and an internal surface defining a bore extending between the first end and the second end. Annular interior sealing elements are disposed at each of the ends of the bushing thereby effecting a sealing engagement between the internal surface of the bushing and the external surface of the rod. An annular exterior sealing element is disposed on the …
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 October 25, 1990 and granted June 21, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 25, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 25, 2012.
- 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.