Packing rings, method for production of the packing rings, and seal device using the packing rings
CA 2125552 C · Owner: Naitou, Kazumasa · Inventors: Ueda, Takahisa; Naito, Shosuke; Fujiwara, Masaru
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A packing ring of a composite structure including a packing of expanded graphite and an annular mass of superposed sheets of expanded graphite is produced by a method including the steps of spirally winding a ribbon of expanded graphite into a roll compression molding the roll into the packing and incorporating the annular mass into the packing by compression molding within a molding die so as to give rise to at least one packed part having a higher density than the packing in at least one of the inner and outer peripheral parts of the packing. A seal device has an empty space through which a shaft passes and containing at least one such packing in the empty space to seal between the inner …
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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 June 9, 1994 and granted February 29, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 9, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 9, 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.