Trench forming assembly and method
CA 2080136 C · Owner: Stegall, Lannie L. · Inventors: Stegall, Lannie L.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An assembly (10) for forming a trench (T) includes one or more frame members (16) that cooperate with a removable form (12) aroundwhich a moldable trench forming composition (C) is poured. The form is made of deformable buoyant material such as expanded polystyrene. Rebar legs (18) are attached to the frame members to provide secure anchoring of the frame members to both the ground (E) and in the trench forming composition. Preferably each frame member includes a horizontal leg that is received in a slot (22) formed in one of the opposing sidewalls of the form. Wire strands (28) are placed within cooperating guide tracks (24) in the opposed ends of the form. The wire strands are pulled …
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 February 8, 1991 and granted May 11, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 8, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 8, 2013.
- 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.