Expired Canadian patentCanada
Signal for telephone trunk lines
CA 72975 A · Owner: The Bell Telephone Company Of Canada · Inventors: Crane, Henry Middlebrook
Overview
Drawings and full text
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordRead 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
- Granted September 3, 1901. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 3, 1918.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJanuary 10, 1901
GrantedSeptember 3, 1901
Term endedSeptember 3, 1918
Patent numberCA 72975 A
Classification (IPC)—
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.