Spring motor
CA 2200022 C · Owner: Martin, Dennis W. · Inventors: Martin, Dennis W.; Afzal, Tariq M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A motor for controlling the elevating and lowering of a load comprises a storage drum, an output drum and a spring member operatively connected therebetween to provide a spring motor therewith, and a pair of cord drums aligned with and respectively adjacent the storage drum and the output drum. A gear train including an idler gear associated with the storage drum drivingly interengages the cord drums with the output drum whereby the elevating and lowering of a load attached to the cords on the cord drums is balanced regardless of whether the elevating or lowering force is applied centrally between the points of attachment of the cords to the load.
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 March 14, 1997 and granted December 21, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 14, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 14, 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.