An alarm element
CA 2181344 C · Owner: Safeplus Ab · Inventors: Asbrink, Leif
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An alarm element forming part of, an alarm system and constructed to receive a magnetic alternating field having the frequency F and transmitted by a transmitter (2), wherein the alarm element is constructed to retransmit a magnetic alternating field without an energy addition, this alternating field being received and detected by a receiver (3). The invention is characterized in that the alarm element (4) has a circuit which includes a coil (L), a capacitance diode (D) and a resistor (R) in series in a, closed circuit and a capacitor (C) con-, nected in parallel across the resistor (R) and in that the coil (L) and the capacitance in the capacitance diode (D) form a resonance circuit having …
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 February 2, 1995 and granted November 28, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 2, 2015.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 2, 2017.
- 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.