Portal crane
CA 2003818 C · Owner: Harnischfeger Corporation · Inventors: Stern, Joseph E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A multilegged portal crane is disclosed in which a plurality of legs including first, second and third spaced apart legs are affixed to a frame with each leg extending between the frame and a different one of a plurality of rails. Each leg has a pair of wheels at a base end spaced, apart in the direction in the length of the rails and rotatable along the rails. A first leg of the plurality of legs has a higher level of rigidity than the other legs which are more flexible relative to the first leg. Means for sensing skew of the crane is mounted on the first leg and the first leg is positioned between the second and third legs such that, for a predetermined amount of skew of the crane …
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 November 24, 1989 and granted March 29, 1994. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 24, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 24, 2011.
- 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.