Method and apparatus for sensing armature position in reluctance electromagnetic actuators
CA 2247809 C · Owner: Li, Long-Jang · Inventors: Li, Long-Jang
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An apparatus detects a position of an armature within a solenoid coil by superimposing a fixed frequency sensing signal onto the coil driver signal. The combined signal is applied to the solenoid coil and an alternating current component varies with changes in inductance of the solenoid coil that result from position changes of the armature. A current sensor produces an output signal indicating a level of current flowing through the solenoid coil and a filter extracts the alternating component of that output signal that results from the sensing signal. A position circuit determines the position of the armature from an output from the filter.
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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 September 25, 1998 and granted October 23, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 25, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 25, 2020.
- 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
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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.