Patent US3626438A successfully refreshed from Google Patents.
US3626438A
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US
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Adjustable stairs
Assignee: Ozark Metal Products Inc
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Filing: 1969-12-15
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Granted: 1971-12-07
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Expires: 1989-12-15
Abstract
Abstract Adjustable stairs are presented by side supports each including a pair of longitudinal stringers and a pair of end links transverse thereto, the four being pivotally joined as a parallelogram. The stair tread and riser span the supports and are pivotally connected thereto, preferably at the angle where the tread and riser meet. The stairs can therefore be manipulated as a flexible assembly to meet the pitch angle required, whereafter the side of the tread is fastened to the stringers to produce a fixed relationship.
Inventors
- 👤 George L Cornell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 11:11
CPC Classifications
E; E04; E04F; E04F11/00; E04F11/02; E04F11/022; E04F11/025; E04F11/0255
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
204 words
Adjustable stairs comprising a pair of opposed side supports the lateral spacing of which characterizes the width of the stairs and each constructed from a pair of spaced parallel stringers and a pair of vertical end links, one stringer being a lower stringer and the other an upper stringer, the end link for each support being respectively connected pivotally to the front end of the stringers of the related support so that each side support may be an adjustable parallelogram, the lower ends of the links extending below the lower stringer to serve as support of the stairs at ground level, and at least one tread and riser stair assembly spanning the side supports, said stair assembly including a horizontal tread and a vertical riser joined together as a rigid one-piece member, the top of the riser is connected pivotally to the upper stringers of each side support, and said assembly is pivotally connected to each lower stringer at the angle between the tread and riser the opposed sides of the front of the tread being connected to the upper stringers to lock the stairs in adjusted position and the riser of the topmost stair assembly having means for attachment to a supporting structure.
Claim 2
Dependent Claim
204 words
Adjustable stairs comprising a pair of opposed side supports the lateral spacing of which characterizes the width of the stairs and each constructed from a pair of spaced parallel stringers and a pair of vertical end links, one stringer being a lower stringer and the other an upper stringer, the end link for each support being respectively connected pivotally to the front end of the stringers of the related support so that each side support may be an adjustable parallelogram, the lower ends of the links extending below the lower stringer to serve as support of the stairs at ground level, and at least one tread and riser stair assembly spanning the side supports, said stair assembly including a horizontal tread and a vertical riser joined together as a rigid one-piece member, the top of the riser is connected pivotally to the upper stringers of each side support, and said assembly is pivotally connected to each lower stringer at the angle between the tread and riser the opposed sides of the front of the tread being connected to the upper stringers to lock the stairs in adjusted position and the riser of the topmost stair assembly having means for attachment to a supporting structure.
Claim 3
Dependent Claim
36 words
Adjustable stairs according to claim 1 wherein the vertical riser and the tread are constructed from angle bars affording a metal framework, the tread support and the riser face being expanded metal fastened to the framework.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-06 | 1975-06-07 | 1975-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-06 | 1979-06-07 | 1979-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-06 | 1983-06-07 | 1983-12-07 | $7700.00 | Window Closed / Lapsed |