US3897665A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Steel stair assembly
Assignee: Individual
•
Filing: 1974-09-03
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Granted: 1975-08-05
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Expires: 1994-09-03
Abstract
Abstract There is provided a steel stair assembly which is fabricated by other than welding to overcome such deficiencies which occur frequently to steel stairs fabricated by welding, e.g., distortion and twist due to welding heat as well as the various resulting drawbacks. The steel stair assembly comprises a pair of opposed plate stringers, and a plurality of L-shaped individual stair units arranged between the pair of the plate stringers and each comprised of a tread and a riser in a continuous form. Each of the L-shaped individual stair units is composed of two sheet steels bonded together, and the individual stair units are interconnected to provide a continuous flight of stairs. Each of the individual stair units is securely connected to the stringers by at least one steel rod disposed between the bonded sheet steels.
Inventors
- 👤 Seibun Yokomori
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 08:51
CPC Classifications
E; E04; E04F; E04F11/00; E04F11/02; E04F11/022; E04F11/025
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
186 words
A steel stair assembly comprising, a pair of plate type stringers arranged opposite to each other, and a plurality of Lshaped unitary individual stair units connected with each other and arranged between said stringers, each of said plurality of Lshaped individual stair units composed of at least two sheet steels bonded together and consisting of a tread portion and a riser portion in continuous form, wherein each of said plurality of stair units includes at least one steel rod close fit and positioned in at least one channel provide on the upper sheet or lower sheet or both of said bonded sheet steels substantially in the central portion of said tread portion, and wherein each of said L-shaped individual stair units further includes a downward bent portion provided at one end of the leg portion thereof, a receiving portion provided at the head portion thereof to receive the downward bent portion of the upper one of said plurality of stair units, and an upward bent portion extended from said receiving portion to cover from above one end of the leg portion of said upper stair unit.
Claim 2
Dependent Claim
186 words
A steel stair assembly comprising, a pair of plate type stringers arranged opposite to each other, and a plurality of Lshaped unitary individual stair units connected with each other and arranged between said stringers, each of said plurality of Lshaped individual stair units composed of at least two sheet steels bonded together and consisting of a tread portion and a riser portion in continuous form, wherein each of said plurality of stair units includes at least one steel rod close fit and positioned in at least one channel provide on the upper sheet or lower sheet or both of said bonded sheet steels substantially in the central portion of said tread portion, and wherein each of said L-shaped individual stair units further includes a downward bent portion provided at one end of the leg portion thereof, a receiving portion provided at the head portion thereof to receive the downward bent portion of the upper one of said plurality of stair units, and an upward bent portion extended from said receiving portion to cover from above one end of the leg portion of said upper stair unit.
Claim 3
Dependent Claim
76 words
A steel stair assembly according to claim 1, wherein said downward portion at one end of the leg portion of each said individual stair unit consists of only the lower sheet of said two sheet steels, and wherein said upward bent portion consists of only the upper sheet of said two sheet steels formed to cover a rising portion of the upper sheet of said upper stair unit at the end of the leg portion thereof.
Claim 4
Dependent Claim
78 words
A steel stair assembly according to claim 1, wherein said downward bent portion at one of the leg portion of each said individual stair unit consists of only the lower sheet of said two sheet steels, and wherein said upward bent portion consists of only the upper sheet of said two sheet steels formed to cover a upwardly protruding step portion of the upper sheet of said upper stair unit at the end of the leg portion thereof.
Claim 5
Dependent Claim
66 words
A steel stair assembly according to claim 1, wherein said downard bent portion at one end of the leg portion of each said individual stair unit consists of only the lower sheet of said two sheet steels, and wherein said upward bent portion consists of only the upper sheet of said two sheet steels formed to cover only the lower sheet of said upper stair unit.
Claim 6
Dependent Claim
28 words
A steel stair assembly according to claim 1, wherein said receiving portion of each said stair unit consists of an opening defined between said upper and lower sheets.
References Cited (Backward Citations)
FR1370733A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-04 | 1979-02-03 | 1979-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-04 | 1983-02-03 | 1983-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-04 | 1987-02-03 | 1987-08-05 | $7700.00 | Window Closed / Lapsed |