Patent US4373609A successfully refreshed from Google Patents.
US4373609A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Stairway stringers constructed of cast, readily-assembled units
Assignee: Individual
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Filing: 1980-12-22
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Granted: 1983-02-15
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Expires: 2000-12-22
Abstract
Abstract A stairway is constructed of one or more stringers which are assembled from a plurality of stringer units of cast material. The stringer units are so constructed as to allow for their simple and rapid assembly on-site into stringers of any desired size and configuration, including stringers of a configuration required for the construction of spiral stairways.
Inventors
- 👤 Victor De Donato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:25
CPC Classifications
E; E04; E04F; E04F11/00; E04F11/02; E04F11/022; E04F11/035
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
146 words
A readily-assembled stringer for constructing a stairway wherein the stringer is formed of a plurality of cast units assembled in a continuous, stepped relationship, each unit comprised of first and second arms and an intermediate member, each of said arms having an end integral with the intermediate member and a free end, said arms being substantially parallel and extending in the same direction and at substantially right angles from the intermediate member, said first arm having a recessed section open at the end of the arm integral with the intermediate member for snugly receiving the free end of the second arm of a first adjacent unit, said free end of the second arm being adapted to be snugly inserted in the recessed section of the first arm of a second adjacent unit, and means for securely fastening together the first and second arms of adjacent units.
Claim 2
Dependent Claim
146 words
A readily-assembled stringer for constructing a stairway wherein the stringer is formed of a plurality of cast units assembled in a continuous, stepped relationship, each unit comprised of first and second arms and an intermediate member, each of said arms having an end integral with the intermediate member and a free end, said arms being substantially parallel and extending in the same direction and at substantially right angles from the intermediate member, said first arm having a recessed section open at the end of the arm integral with the intermediate member for snugly receiving the free end of the second arm of a first adjacent unit, said free end of the second arm being adapted to be snugly inserted in the recessed section of the first arm of a second adjacent unit, and means for securely fastening together the first and second arms of adjacent units.
Claim 3
Dependent Claim
31 words
Stringers formed of units as defined in claim 1 wherein the units are made of a cast material selected from the group consisting of steel, iron, aluminum, bronze, brass and plastic.
Claim 4
Dependent Claim
44 words
Stringers formed of units as defined in claim 1, wherein the free end of the second arm is rotatably received within the recessed section of the first arm of adjacent units and the units arranged into a spiral configuration to support a spiral stairway.
Claim 5
Dependent Claim
21 words
A stairway constructed of a single stringer as defined in claim 3 wherein the stringer is positioned centrally of the stairway.
Claim 6
Dependent Claim
31 words
Stringers formed of units as defined in claim 4 wherein the units are made of a cast material selected from the group consisting of steel, iron, aluminum, bronze, brass and plastic.
Claim 7
Dependent Claim
34 words
Stringers formed of units as defined in claim 1 wherein the recessed section in the first arm includes a shoulder on which the free end of the second arm of an adjacent unit rests.
Claim 8
Dependent Claim
159 words
Stringers formed of units as deferred in claim 6 wherein the second arm is open from its end integral with the intermediate member to its free end, the size of the opening adjacent the free end being less than the size of the remainder of the opening so as to form a shoulder within the second arm adjacent its free end, and the means for securely fastening together the first and second arms of adjacent units comprises a first threaded member threaded to the free end of the first arm and extending into the recess in said first arm and into the opening in the second arm of an adjacent unit beyond the shoulder within the second arm and a second threaded member threaded onto the first threaded member so as to bear against the shoulder within the second arm and force the free end of the second arm into intimate contact with the shoulder in the first arm.
Claim 9
Dependent Claim
44 words
Stringers formed of units as defined in claim 7 wherein the free end of the second arm is rotatably received within the recessed section of the first arm of adjacent units and the units arranged into a spiral configuration to support a spiral stairway.
Claim 10
Dependent Claim
21 words
A stairway constructed of a single stringer as defined in claim 8 wherein the stringer is positioned centrally of the stairway.
Claim 11
Dependent Claim
31 words
Stringers formed of units as defined in claim 9 wherein the units are made of a cast material selected from the group consisting of steel, iron, aluminum, bronze, brass and plastic.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-02-14 | 1986-08-16 | 1987-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-14 | 1990-08-16 | 1991-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-14 | 1994-08-16 | 1995-02-15 | $7700.00 | Window Closed / Lapsed |