Acoustic digitizing system
CA 2124181 A1 · Owner: Gilchrist, Ian R. · Inventors: Gilchrist, Ian R.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
An acoustic position sensing apparatus is described which determines the position of an indicator in relation to a datum surface or volume. The apparatus comprises an acoustic point source transmission device mounted on the indicator for transmitting a sequence of periodic acoustic oscillations, and a plurality of acoustic point receivers positioned about the datum surface for receiving the acoustic oscillations. Comparators are connected to each acoustic receiver for converting the received acoustic oscillations to square waves having logical up and down levels. A register or other time determining circuit is coupled to each comparator and receives at least a leading portion of a square …
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 4, 1990. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended September 4, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 4, 2012.
- 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.