Apparatus for the determination and evaluation of coal chemistry based on the genetics of fossil fuels
US 7,809,526 Lapsed on the fee recordLapsed Oct 5, 2022 on the fee record · From the USPTO record
20-year base term ended Mar 17, 2026
Third maintenance fee unpaid; grace period ended.
Mar 17, 2006
Oct 5, 2022
Oct 5, 2010
Mar 29, 2026
How we calculated this date
| Step | Input | Date after this step | Confidence |
|---|---|---|---|
| Base term, 20 years from filing | Clock starts Mar 17, 2006, when the earliest non-provisional application in its chain was filed (this one was filed Jan 17, 2008) | Mar 17, 2026 | High confidence |
| Continuity chain | Every parent in the chain resolved | no change | High confidence |
| Patent term adjustment | +12 days, USPTO patent term adjustment record | Mar 29, 2026 | High confidence |
| Terminal disclaimer cap | None on record | no cap applied | High confidence |
| Patent term extension | None on file | no change | High confidence |
| Fee events | 2 of 3 maintenance fees paid | lapsed Oct 5, 2022 | High confidence |
| Computed term end | The steps above, in order | Oct 5, 2022 | From the USPTO record |
Sources
Google Patents · The patent document at USPTO · Assignment records at USPTO
USPTO account required: This application in Patent Center · USPTO's maintenance fee lookup
Maintenance fee events come from USPTO's own fee records. Its fee lookup asks for the patent number and the application number.
Not on this page: the patent's family, its recorded assignments and its citation count. USPTO's assignment records, linked above, list every recorded assignment.
Every date shows its work: the base term, any term adjustment or extension, any disclaimer cap, and the maintenance fee record, each with a confidence tier. How this record was built
Computed patent terms end on the dates shown. Related patents and pending applications may cover overlapping subject matter.