E04F 11/032
Spiral stairways supported by a central column
E04F11/032 (Spiral stairways supported by a central column) appears on 44 US grants and 25 published applications in this corpus.
Search patents in E04F- Granted patents
- 44
- Published applications
- 25
- Assignees
- 19
- Inventors
- 74
- Latest grant
- 28 Oct 2025
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 1 | 0 |
| 1977 | 0 | 0 |
| 1978 | 1 | 0 |
| 1979 | 1 | 0 |
| 1980 | 2 | 0 |
| 1981 | 0 | 0 |
| 1982 | 1 | 0 |
| 1983 | 1 | 0 |
| 1984 | 1 | 0 |
| 1985 | 1 | 0 |
| 1986 | 1 | 0 |
| 1987 | 2 | 0 |
| 1988 | 2 | 0 |
| 1989 | 1 | 0 |
| 1990 | 0 | 0 |
| 1991 | 0 | 0 |
| 1992 | 1 | 0 |
| 1993 | 0 | 0 |
| 1994 | 0 | 0 |
| 1995 | 0 | 0 |
| 1996 | 3 | 0 |
| 1997 | 1 | 0 |
| 1998 | 1 | 0 |
| 1999 | 2 | 0 |
| 2000 | 3 | 0 |
| 2001 | 0 | 0 |
| 2002 | 0 | 0 |
| 2003 | 1 | 0 |
| 2004 | 0 | 0 |
| 2005 | 0 | 1 |
| 2006 | 0 | 0 |
| 2007 | 0 | 1 |
| 2008 | 0 | 1 |
| 2009 | 0 | 1 |
| 2010 | 0 | 1 |
| 2011 | 1 | 3 |
| 2012 | 2 | 0 |
| 2013 | 0 | 0 |
| 2014 | 0 | 0 |
| 2015 | 0 | 0 |
| 2016 | 0 | 2 |
| 2017 | 2 | 2 |
| 2018 | 0 | 0 |
| 2019 | 4 | 2 |
| 2020 | 0 | 2 |
| 2021 | 0 | 3 |
| 2022 | 1 | 2 |
| 2023 | 3 | 3 |
| 2024 | 1 | 0 |
| 2025 | 3 | 0 |
| 2026 | 0 | 1 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Folding stair with tread overhang28 Oct 2025US 12,454,831 B2
- Spiral staircase23 Sep 2025US 12,421,729 B2
- Guard assemblies29 Apr 2025US 12,286,793 B2
- Elevating apparatus based on hetero-oriented, non-isometric, dual-spiral drive structure26 Mar 2024US 11,939,190 B2Jiangsu Zhiji Enviornmental Protection Technology Co., Ltd.
- Freestanding modular spiral staircase18 Apr 2023US 11,629,500 B2
- Modular Mining Escapeway9 Jul 2026US 2026/0193986 A1RAM Enterprise, Inc.
- Spiral staircase14 Dec 2023US 2023/0399851 A1
- Folding Stair with Tread Overhang7 Dec 2023US 2023/0392383 A1
- Guard Assemblies2 Feb 2023US 2023/0033898 A1
- Vertical Flood Escape Structure3 Nov 2022US 2022/0349201 A1The Government of the United States of America, as represented by the Secretary of Homeland Security
Most cited
By later US patents
- Adjustable pitch spiral stairway kit17US 5,557,893 A1996
- Multi-unit stair construction and method16US 4,850,164 A1989
- Circular stairway and method of making same16US 5,632,124 A1997
- Spiral climb in surrounding enclosure14US 6,108,988 ASoft Play, L.L.C. · 2000
- Method for fabricating wooden circular stair with balustrade12US 4,722,374 A1988