Expired Canadian patentCanada
Telephone exchange system
CA 318924 A · Owner: The Western Electric Company · Inventors: Richard Churchill Davis; Linus E. Kittredge; Warren Wesley Carpenter
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 January 12, 1932. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 12, 1949.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Filed—
GrantedJanuary 12, 1932
Term endedJanuary 12, 1949
Patent numberCA 318924 A
Classification (IPC)H04M3/00 +1 more
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.