H01F 7/1844
Monitoring or fail-safe circuits
Official title: {Monitoring or fail-safe circuits (for relays H01H47/002)}
H01F7/1844 (Monitoring or fail-safe circuits) appears on 518 US grants and 491 published applications in this corpus.
Search patents in H01F- Granted patents
- 518
- Published applications
- 491
- Assignees
- 325
- Inventors
- 1,224
- Latest grant
- 18 Aug 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1977 | 1 | 0 |
| 1978 | 0 | 0 |
| 1979 | 1 | 0 |
| 1980 | 1 | 0 |
| 1981 | 1 | 0 |
| 1982 | 3 | 0 |
| 1983 | 0 | 0 |
| 1984 | 0 | 0 |
| 1985 | 1 | 0 |
| 1986 | 1 | 0 |
| 1987 | 2 | 0 |
| 1988 | 2 | 0 |
| 1989 | 3 | 0 |
| 1990 | 4 | 0 |
| 1991 | 2 | 0 |
| 1992 | 2 | 0 |
| 1993 | 4 | 0 |
| 1994 | 3 | 0 |
| 1995 | 9 | 0 |
| 1996 | 8 | 0 |
| 1997 | 8 | 0 |
| 1998 | 16 | 0 |
| 1999 | 14 | 0 |
| 2000 | 10 | 0 |
| 2001 | 12 | 2 |
| 2002 | 11 | 9 |
| 2003 | 8 | 9 |
| 2004 | 9 | 15 |
| 2005 | 10 | 17 |
| 2006 | 9 | 11 |
| 2007 | 10 | 23 |
| 2008 | 14 | 22 |
| 2009 | 11 | 29 |
| 2010 | 19 | 18 |
| 2011 | 13 | 13 |
| 2012 | 13 | 11 |
| 2013 | 14 | 15 |
| 2014 | 11 | 9 |
| 2015 | 13 | 22 |
| 2016 | 16 | 15 |
| 2017 | 15 | 26 |
| 2018 | 18 | 33 |
| 2019 | 38 | 27 |
| 2020 | 25 | 27 |
| 2021 | 22 | 35 |
| 2022 | 26 | 35 |
| 2023 | 28 | 21 |
| 2024 | 29 | 20 |
| 2025 | 19 | 12 |
| 2026 | 9 | 15 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
Recent patents
- Dialysis system having reduced valve noise18 Aug 2026US 12,712,080 B2Vantive Health GmbH
- Dialysis system having a valve functionality assessment16 Jun 2026US 12,658,323 B2Vantive Health GmbH
- Solenoid position sensing16 Jun 2026US 12,658,348 B2Rivian IP Holdings, LLC
- Method for determining the position of an armature of an electromagnet and fluid system2 Jun 2026US 12,644,540 B2HAWE Hydraulik SE
- Detecting pickup and dropout of solenoid valve26 May 2026US 12,638,102 B2Automatic Switch Company
- Method and system for enhancing subsurface permeability via electromagnetic fields and electromagnetically responsive particles27 Aug 2026US 2026/0251044 A1
- Solenoid actuator efficiency optimization13 Aug 2026US 2026/0237547 A1Analog Devices International Unlimited Company
- Circuit and method for driving an inductive load with reduced power loss13 Aug 2026US 2026/0237548 A1
- Electromagnet current control method and related assembly6 Aug 2026US 2026/0229393 A1Crrc Qingdao Sifang Co., Ltd.
- Demagnetization of working-channel tools in an electromagnetically tracked endoscope30 Jul 2026US 2026/0221326 A1Magnisity Ltd.
Most cited
By later US patents
- Method of operating an electromagnetically actuated fuel intake or exhaust valve of an internal combustion engine102US 4,823,825 A1989
- Monitor and control circuit for electric surface controlled subsurface valve system91US 5,293,551 AOtis Engineering Corporation · 1994
- Solenoid driver control circuit with initial boost voltage87US 4,729,056 AMotorola, Inc. · 1988
- Method of identifying the impact of an armature onto an electromagnet on an electromagnetic switching arrangement85US 5,708,355 AFEV Motorentechnik GmbH · 1998
- Method and apparatus for determining the position of an armature in an electromagnetic actuator83US 5,481,187 ACaterpillar Inc. · 1996