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US3970401A Expired / Lapsed US ⏱️ 0.0 years remaining

Tubular structures

Assignee: Individual
•
Filing: 1974-05-28
•
Granted: 1976-07-20
•
Expires: 1994-05-28
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Abstract

Abstract The structures of the present invention start with a basic hollow tube of any desired outer shape and made of paper, plastic or metal. When paper is used, it is vacuum impregnated with a plastic resin and oven baked to give it rigidity. The tube may also be covered with an ornamental veneer, if desired. The tubes are provided with suitable openings to receive matching counterparts fitting against the openings. Strong, rigid core members of wood, plastic or metal are positioned in the tubular members with the abutting portions of the core members interconnected. The structure is placed in a clamp to hold the parts together in proper position. Polyurethane is then poured into one end, the end is capped, and the structure is rotated to evenly distribute the polyurethane. The urethane sets at room temperature and expands as it sets to internally mold the members into a solid structure. The finished structure can be drilled, machined, or bolted to add features in the conventional manner.

Inventors

  • 👤 Donald Lubeck

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-23 10:10
CPC Classifications
F; F16; F16B; F16B12/00; F16B12/40; Y; Y10; Y10S; Y10S297/00; Y10S297/01; Y10S297/02; Y10T; Y10T403/00; Y10T403/47

Claims Analysis

Total Claims: 5
Claim 1
Independent Claim 154 words
A free standing portable structure that is capable of supporting loads thereon, comprising a plurality of hollow tubular members that are interfitted to define a unitary construction, said members being formed of an oven baked resin impregnated paper, each of said members having a reinforcing core located therein that extends substantially the length thereof, the core of each member occupying less than the total volume therein to define an interior space therein, each member having portions of the core therein exposed at predetermined locations, the core of each member at an exposed location engaging an exposed core of an adjacent member for interengaging the members, a plurality of communicating channels being defined by the interior spaces of the members that are interengaged by the cores therein, and a polyurethane filler material extending throughout the interior of said members and occupying the spaces formed therein to positively interlock the members together in the unitary construction.
Claim 2
Dependent Claim 154 words
A free standing portable structure that is capable of supporting loads thereon, comprising a plurality of hollow tubular members that are interfitted to define a unitary construction, said members being formed of an oven baked resin impregnated paper, each of said members having a reinforcing core located therein that extends substantially the length thereof, the core of each member occupying less than the total volume therein to define an interior space therein, each member having portions of the core therein exposed at predetermined locations, the core of each member at an exposed location engaging an exposed core of an adjacent member for interengaging the members, a plurality of communicating channels being defined by the interior spaces of the members that are interengaged by the cores therein, and a polyurethane filler material extending throughout the interior of said members and occupying the spaces formed therein to positively interlock the members together in the unitary construction.
Claim 3
Dependent Claim 18 words
A structure as in claim 1, wherein said reinforcing cores comprise elongated wooden cores of rectangular cross section.
Claim 4
Dependent Claim 36 words
A structure as in claim 1, wherein said cores are joined by a tongue and groove arrangement, the tongue being formed on a first core and being received in a groove formed in a mating core.
Claim 5
Dependent Claim 17 words
A structure as in claim 1, wherein said hollow tubular members include exposed surfaces of ornamental veneer.

References Cited (Backward Citations)

US1053646A Cited
US2189201A Cited
US3039727A Cited
US3386119A Cited
US3608007A Cited
US3664693A Cited
US3639001A Cited
US3798869A Cited
US3680898A Cited
US3798867A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1979-07-20 1980-01-19 1980-07-20 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1983-07-20 1984-01-19 1984-07-20 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1987-07-20 1988-01-19 1988-07-20 $7700.00 Window Closed / Lapsed

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