Patent US2732884A successfully refreshed from Google Patents.
Patent US4032394A successfully refreshed from Google Patents.
US4032394A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making wet-pressed fiberboard of high resistance to bending
Assignee: Individual
•
Filing: 1975-05-20
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Granted: 1977-06-28
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Expires: 1995-05-20
Abstract
Abstract Wet pressed fiber board material of high resistance to bending is produced by preparing a layer of fiber from a water suspension of the fiber, said layer being de-watered and pressed to form a coherent flat sheet, wherein raw material is distributed over the surface of said layer in varying quantities and/or qualities in a manner such that the pressed board obtains strip-like surface portions which extend in at least one direction of the horizontal plane of the sheet, said strip-like surface portions having varying density and/or strength properties, whereby the finished board has a higher resistance to bending than a homogeneous sheet having substantially the same average density.
Inventors
- 👤 Ernst Ludvig Back
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:46
CPC Classifications
D; D21; D21J; D21J1/00; D21J1/16
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
100 words
In a method of manufacturing wet-pressed fiber board material of uniform thickness in which a layer of fiber-water suspension is prepared, said layer being de-watered and pressed to form a coherent flat sheet, the improvement comprising distributing said fiber-water suspension over the surface of said layer in a manner such that the pressed board product contains strip-like surface portions which extend in at least one direction of the horizontal plane of the sheet, said strip-like surface portions having varying densities, whereby the finished board has a higher resistance to bending than a homogeneous sheet having substantially the same average density.
Claim 2
Dependent Claim
100 words
In a method of manufacturing wet-pressed fiber board material of uniform thickness in which a layer of fiber-water suspension is prepared, said layer being de-watered and pressed to form a coherent flat sheet, the improvement comprising distributing said fiber-water suspension over the surface of said layer in a manner such that the pressed board product contains strip-like surface portions which extend in at least one direction of the horizontal plane of the sheet, said strip-like surface portions having varying densities, whereby the finished board has a higher resistance to bending than a homogeneous sheet having substantially the same average density.
Claim 3
Dependent Claim
63 words
The method of claim 1 in which the fiber layer is formed by de-watering the suspension on a wire screen, wherein fiber suspensions having different fiber concentrations are supplied to the wire screen at the same speed from a sectioned head box in a manner such that the board obtained contains strip-like surface portions of mutually different densities extending in the machine direction.
Claim 4
Dependent Claim
19 words
The method of claim 2, wherein the difference in densities of the strip-like surface portions is at least 20%.
Claim 5
Dependent Claim
19 words
The method of claim 3, wherein the difference in the densities of the strip-like portions is at least 30%.
Claim 6
Dependent Claim
18 words
The method of claim 3, wherein the surface portions of higher density are provided with a binding agent.
Claim 7
Dependent Claim
13 words
The method of claim 5, wherein said binding agent is a thermosetting resin.
Claim 8
Dependent Claim
29 words
The method of claim 2, wherein the surface portions of higher density comprise a raw fibrous material which has greater mechanical strength than the surface portions of lower density.
Claim 9
Dependent Claim
31 words
The method of claim 2, wherein the board comprises multiple layers, and the center layer of the board is provided with a binding agent over the whole width of the board.
Claim 10
Dependent Claim
39 words
The method of claim 2, wherein surface portions of higher density are situated at positions on the sheet which are to form the two of the outer edges of a board which has been sawn to the desired size.
Claim 11
Dependent Claim
21 words
The method of claim 2, wherein the surface portions of higher density constitute 10-50% of the total surface of the board.
Claim 12
Dependent Claim
21 words
The method of claim 10, wherein said surface portions of higher density constitute 15-30% of the total surface of the board.
References Cited (Backward Citations)
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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) | 1980-06-27 | 1980-12-27 | 1981-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-06-27 | 1984-12-27 | 1985-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-06-27 | 1988-12-27 | 1989-06-28 | $7700.00 | Window Closed / Lapsed |