Elevator counterweight system
CA 2414748 C · Owner: Haynes, Harold H. · Inventors: Haynes, Harold H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A counterweight for an elevator is defined by a disc which can be slidably mounted in tracks in an elevator shaft. Annular grooves in the periphery of the disc receive cables which are anchored at the top of the shaft and extend around pulleys on the rear of a car and a sheave driven by a reversible motor whereby when the motor is actuated, the elevator moves vertically in one direction while the counterweight rotates and moves vertically in the opposite direction.
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 December 19, 2002 and granted July 5, 2011. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 19, 2022.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 19, 2024.
- 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.