Method and apparatus for cleaning ballast
CA 2074718 C · Owner: Kershaw Manufacturing Company Inc. · Inventors: Whitaker, John B. Jr.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An articulated ballast cleaning system utilizes a pair of ditcher wheels (26 27) each dedicated to removing only the peripheral ballast from adjacent the ends of crossties (14). Undercutter (42) removes the ballast from beneath the center of the crossties (14). A, screen cleaner (31) is provided to separate spoil from reusable ballast removed by the ditcher wheels (26 27) whereas, ballast cleaner (41) is provided to separate spoil from reusable ballast removed by undercutter (42). The reusable ballast is cleaned by screen cleaner (31) and ballast cleaner (41). Spoil or waste ballast is conveyed forwardly along the apparatus for disposal, while cleaned ballast is conveyed rearwardly …
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 January 24, 1991 and granted November 9, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 24, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 24, 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.