Return spring for clutch
CA 2217624 C · Owner: Itonaga, Kazuhiro · Inventors: Sasuga, Ichiro; Tokumasu, Jun; Kawanabe, Kenjiro
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
20-, A compression coil spring is used as a return spring which is stored in the housing of a clutch to urge the clutch piston in its returning direction. The effective number of turns of the compression coil spring is two or less, and the number of turns at an end-turn portion thereof is more than 0.45 and not more than 0.7. The compression coil spring is used in the compressed state throughout the operating stroke of the clutch piston. The number of turns at the end-turn portion is desirably within the range of 0.5 to 0.65 more desirably within the range of 0.55 to 0.62.
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 2, 1997 and granted June 19, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 2, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 2, 2019.
- 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.