RankingsPrimerArbiterPhysicistMathematicianContrarianQESites logClaimsSourcesResearch notes

Google Patents: 2026-10-06 (Investigator, Step I, run 1)

Site: https://patents.google.com/ (Chrome for search lists; the patent detail pages render no readable text in Chrome, so the detail pages were read with the web-fetch fallback.)

Queries

  1. inventor:(Edwin V Gray) before:priority:19900101 (Chrome)
  2. Detail page US3890548A (web-fetch)
  3. Detail page US4595975A (web-fetch)
  4. (regenerative energy recovery) inventor:Gray before:priority:19820101 after:priority:19780101 (Chrome)
  5. (capacitor inductive load battery) inventor:(Edwin Gray) country:GB (Chrome)

Found

  • US 3,890,548 has foreign family members [web: https://patents.google.com/patent/US3890548A/en]: Canada CA 1030600 A (application CA 211,165) and Japan JPS 5074712 A (application JP 49-127019). Assignee EVGRAY Enterprises Inc; filed 1973-11-02, published 1975-06-17; status "Expired - Lifetime". The folder's documents never mention these filings. A Japanese filing fits the press accounts of a Japanese backer (Pan World Enterprises, see rexresearch notes) [inference, to be checked].
  • US 4,595,975 [web: https://patents.google.com/patent/US4595975A/en]: filed 1984-10-18, published 1986-06-17, status "Expired - Fee Related", lapsed 1990-06-17 (maintenance fee not paid). That is about two months after the death date on Gray's VA burial record (20 April 1990; see findagrave notes). No foreign family members were reported for it.
  • US 4,661,747 [web: search list, query 1]: Google lists priority 1983-12-16, filed 1985-10-25, granted 1987-04-28. The book gives only the division from application 662,339 (filed 1984-10-18). A December 1983 priority date points to an earlier application not named in the folder. To check.
  • Query 4 (a 1980 "Regenerative Energy Recovery System" application, named on rexresearch): no Gray result (one unrelated Siemens hit). Query 5 (GB): no results shown. Negative for these queries. Espacenet was not reached.
  • Cited-by lists were not extracted (the web-fetch summary did not return them). Next run.

Bearing on the claims

  • Claim 1 / the Gray patent family: Gray protected the 1973 motor in Canada and Japan as well. Those texts may differ from the US text (claims, drawings, any figures). Lindemann does not mention them.
  • Claim 5 (history): the '975 fee lapse in June 1990 is an independent, dated public record that fits the 1990 death date on the VA burial record.