Coupling for spiral counterbalance
CA 2210096 C · Owner: Newton, William P. · Inventors: Habbersett, John I.; Newton, William P.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A coupling between a twisted rod and a torsion spring of a spiral counterbalance is found to be subject to deformation against the twisted rod from compressive force of the grip of the terminal convolutions of the torsion spring. This problem is solved by using a metal cylinder in the rotation transmission sleeve of the coupling to resist the compressive force and prevent deformation so that the twisted rod can move freely within the coupling. This solution also allows the use of a stronger torsion spring to exert a larger counterbalance force.
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 July 9, 1997 and granted September 12, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 9, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 9, 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.