E21D 23/20
For sequential movement
Official title: for sequential movement, e.g. one behind the other
E21D23/20 (For sequential movement) appears on 6 US grants and 0 published applications in this corpus.
Search patents in E21D- Granted patents
- 6
- Published applications
- 0
- Assignees
- 5
- Inventors
- 12
- Latest grant
- 13 Feb 1990
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1978 | 1 | 0 |
| 1979 | 0 | 0 |
| 1980 | 0 | 0 |
| 1981 | 1 | 0 |
| 1982 | 0 | 0 |
| 1983 | 1 | 0 |
| 1984 | 2 | 0 |
| 1985 | 0 | 0 |
| 1986 | 0 | 0 |
| 1987 | 0 | 0 |
| 1988 | 0 | 0 |
| 1989 | 0 | 0 |
| 1990 | 1 | 0 |
By publication year. Applications have been published since 2001.
Recent patents
- Electrohydraulic coal-mining system13 Feb 1990US 4,900,091 ABochumer Eisenhutte Heintzmann GmbH & Co. KG
- Mine-roof support control means16 Oct 1984US 4,476,898 AHermann Hemscheidt Maschinenfabrik GmbH & Co.
- Control systems for mineral mining installations29 May 1984US 4,451,181 AGewerkschaft Eisenhutte Westfalia
- Hydraulically-operated devices27 Dec 1983US 4,422,808 ADowty Mining Equipment Limited
- Thrust device using hydraulic jacks3 Feb 1981US 4,248,136 ACharbonnages de France
No published applications in this class yet.
Most cited
By later US patents
- Control systems for mineral mining installations7US 4,451,181 AGewerkschaft Eisenhutte Westfalia · 1984
- Longwall mining apparatus6US 4,109,472 ADowty Mining Equipment Limited · 1978
- Electrohydraulic coal-mining system4US 4,900,091 ABochumer Eisenhutte Heintzmann GmbH & Co. KG · 1990
- Mine-roof support control means1US 4,476,898 AHermann Hemscheidt Maschinenfabrik GmbH & Co. · 1984