Coupling system for smoke detector units
CA 2073854 A1 · Owner: Westman, Terho · Inventors: Westman, Terho; Kuitunen, Kari
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A coupling system for smoke detector units said, system comprisomg a plurality of smoke detector units having their outgoing alarm signal wires coupled to one or a plurality of common alarm and/or signalling devices characterized, in that at least some of the alarm signal wires extending from smoke detector units are fitted with a diode or a like current-directing alement which is coupled to permit the passage of alarm signal current away from unit but to prevent the alarm signal current from reaching said unit and that said alarm, signal wires are downstream of the current-directing elements combined together to provide a joint alarm signal wire for a plurality of smoke detector units.
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 2, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended January 2, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 2, 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.