Method and apparatus for testing chew-out strength of paperboard core
CA 2128776 C · Owner: Sonoco Products Company · Inventors: Tiffin, Ronald C.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention provides a method and apparatus for testing the chew-out strength of paperboard cores. The apparatus of the invention includes a clamping element for clamping a tubular core to prevent rotation thereof; a splined chuck element in the form of an axially tapered member having a plurality of circumferentially distributed splines for insertion into one end face of the core; and a means for applying increasing torque at a controlled rate to the splined chuck element. A measuring means measures the torque applied to the splined chuck element. In operation increasing amounts of torque are applied by the torquing means until the splined chuck element shears the end face of the tube …
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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 25, 1994 and granted January 14, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 25, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 25, 2016.
- 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.