Ultrasonic apparatus
CA 2214961 C · Owner: Roberts, Allan J. · Inventors: Roberts, Allan J.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
In an ultrasonic apparatus a plurality of piezoelectric electroacoustic transducers (10, 12) are mechanically coupled to a horn (14) for providing ultrasonic vibrations thereto and the, transducers are energized in parallel from a common electrical power supply (28). In order to avoid the presence of circulating currents among the transducers, transformer balancing units (30) are connected in circuit with each of the transducers. Since the use of parallel connected piezoelectric transducers increases the total circuit capacitance, series connected capacitors (32 34), are provided to restore the circuit capacitance to a value required for the resonant circuit condition.
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 September 22, 1997 and granted September 12, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 22, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 22, 2019.
- 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.