Method of straightening heat seals on plastic film zipper bags
CA 2063059 C · Owner: Mobil Oil Corporation · Inventors: Herrington, Fox John, Jr.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In the manufacture of plastic articles such as thermoplastic film zipper bags and the like heat sealing the film try the zipper produces a seal line that shrinks, resulting in unsightly appearance. An apparatus and method are disclosed for restoring the shrunk seal line to its original length by corrugating and stretching it between mating teeth. A method is also disclosed for restretching the seal without corrugation.
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 13, 1992 and granted December 12, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 13, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 13, 2014.
- 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.