H02K 7/1884
Structurally associated with free piston engines
Official title: {structurally associated with free piston engines}
H02K7/1884 (Structurally associated with free piston engines) appears on 155 US grants and 142 published applications in this corpus.
Search patents in H02K- Granted patents
- 155
- Published applications
- 142
- Assignees
- 68
- Inventors
- 210
- Latest grant
- 25 Aug 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1979 | 1 | 0 |
| 1980 | 1 | 0 |
| 1981 | 1 | 0 |
| 1982 | 1 | 0 |
| 1983 | 2 | 0 |
| 1984 | 3 | 0 |
| 1985 | 1 | 0 |
| 1986 | 0 | 0 |
| 1987 | 1 | 0 |
| 1988 | 0 | 0 |
| 1989 | 1 | 0 |
| 1990 | 0 | 0 |
| 1991 | 1 | 0 |
| 1992 | 1 | 0 |
| 1993 | 0 | 0 |
| 1994 | 1 | 0 |
| 1995 | 1 | 0 |
| 1996 | 0 | 0 |
| 1997 | 1 | 0 |
| 1998 | 1 | 0 |
| 1999 | 2 | 0 |
| 2000 | 2 | 0 |
| 2001 | 11 | 0 |
| 2002 | 5 | 2 |
| 2003 | 1 | 5 |
| 2004 | 4 | 1 |
| 2005 | 4 | 5 |
| 2006 | 3 | 4 |
| 2007 | 1 | 4 |
| 2008 | 3 | 2 |
| 2009 | 3 | 4 |
| 2010 | 5 | 8 |
| 2011 | 3 | 8 |
| 2012 | 3 | 10 |
| 2013 | 10 | 5 |
| 2014 | 7 | 3 |
| 2015 | 3 | 3 |
| 2016 | 1 | 5 |
| 2017 | 1 | 3 |
| 2018 | 5 | 4 |
| 2019 | 6 | 8 |
| 2020 | 9 | 13 |
| 2021 | 5 | 1 |
| 2022 | 5 | 15 |
| 2023 | 15 | 8 |
| 2024 | 9 | 6 |
| 2025 | 6 | 11 |
| 2026 | 5 | 4 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- High-power core system25 Aug 2026US 12,719,334 B2Mainspring Energy, Inc.
- Integrated piston assembly for an electric machine2 Jun 2026US 12,646,997 B2Hyliion Holdings Corp.
- System and method of generating electricity using renewable energy from environment2 Jun 2026US 12,647,012 B2
- Core synchronization for linear generators24 Mar 2026US 12,587,118 B2Mainspring Energy, Inc.
- Integrated linear generator system17 Feb 2026US 12,556,063 B2Mainspring Energy, Inc.
- Energy storage and conversion in linear generators9 Jul 2026US 2026/0194003 A1Mainspring Energy, Inc.
- Core synchronization for linear generators25 Jun 2026US 2026/0180479 A1Mainspring Energy, Inc.
- Electric Power Generating Apparatus And Method Of Operating Same28 May 2026US 2026/0149396 A1NovoPower International Inc.
- Linear electromagnetic machine system5 Mar 2026US 2026/0066758 A1Mainspring Energy, Inc.
- Integrated counterweight for an electric machine4 Dec 2025US 2025/0373116 A1Hyliion Holdings Corp.
Most cited
By later US patents
- Hybrid electric propulsion system164US 5,172,784 A1992
- Method and means for powering portable oxygen supply systems108US 5,370,112 ADeVilbiss Health Care, Inc. · 1994
- Double acting thermodynamically resonant free-piston multicylinder stirling system and method78US 7,134,279 B2Infinia Corporation · 2006
- Method and apparatus for producing electrical energy from a cyclic combustion process utilizing coupled pistons which reciprocate in unison73US 4,532,431 ACUV "Progress" · 1985
- Linear electromagnetic machine69US 4,454,426 ANew Process Industries, Inc. · 1984