Counterbalancing mechanism for an overhead door
CA 2191102 C · Owner: Clopay Building Products Company, Inc. · Inventors: Agin, Thomas E.; Leist, Alan R.; Carper, George S.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An overhead door apparatus (10) utilizing a torsion spring counterbalancing mechanism (30). The counterbalancing mechanism (30) includes a worm drive ring-shaped gear winding mechanism (38) for setting the appropriate torque or number of winds in the spring (32). A counting mechanism (140) is provided to indicate to the installer the number of winds being given to the spring (32). Means are also provided for accommodating spring growth and contraction during winding and unwinding using the winding mechanism (38) and during normal raising and lowering of the door (12). A spring clip gear retainer (82) is disclosed for preventing rotation or creep of the worm drive gear (70) and spur gear …
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 June 13, 1995 and granted January 25, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 13, 2015.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 13, 2017.
- 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.