US4378405A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of building board
Assignee: BPB Ltd
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Filing: 1981-09-17
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Granted: 1983-03-29
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Expires: 2001-09-17
Abstract
Abstract A building board comprises a core 31 of set cementitious material, such as gypsum, faced on at least one side by a fabric or web 33 of mineral fibres embedded in the face of the core and a continuous film 32 of the cementitious material having a higher density and lower porosity than the core extending over the outer face of the fabric. The film may have a smooth surface or a desired textured or figured surface. The preferred fabric or web 33 is a non-woven glass fibre tissue and it is preferred that a continuous film 32 of gypsum at the surface should not exceed 2 mm in thickness. The board is made by bringing the fabric or web into contact with the respective face of a layer of an aqueous slurry of gypsum plaster or other cementitious material, and vibrating the layer of slurry in contact with the fabric or web until slurry penetrates the web and the latter is completely embedded. The process can be carried out continuously by supporting the slurry between flexible belts which are vibrated by mechanical action applied to their faces remote from the slurry. Boards accordingly to the invenion can have greater strength and/or greater resistance to fire than conventional paper-faced gypsum board.
Inventors
- 👤 Thomas A. Pilgrim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 09:16
CPC Classifications
C; C04; C04B; C04B14/00; C04B14/38; C04B14/42; B; B28; B28B; B28B19/00; B28B19/0092; B28B23/00; B28B23/0006; B28B5/00; B28B5/02; B28B5/026; B28B5/027; E; E04; E04C; E04C2/00; E04C2/02; E04C2/04; E04C2/043; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249994; Y10T428/249999
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
87 words
A method for making a building board having a pervious fabric embedded in at least one face thereof, said method consisting essentially of advancing a first support surface and a second support surface in converging relationship to each other, applying a layer of a pervious fabric to at least one of the support surfaces, depositing an aqueous slurry of cementitious material such as gypsum plaster between the advancing support surfaces and vibrating the support surface in contact with the fabric until the slurry penetrates through the fabric.
Claim 2
Independent Claim
87 words
A method for making a building board having a pervious fabric embedded in at least one face thereof, said method consisting essentially of advancing a first support surface and a second support surface in converging relationship to each other, applying a layer of a pervious fabric to at least one of the support surfaces, depositing an aqueous slurry of cementitious material such as gypsum plaster between the advancing support surfaces and vibrating the support surface in contact with the fabric until the slurry penetrates through the fabric.
Claim 3
Dependent Claim
44 words
The method of claim 1 wherein the first support surface converges with the second support surface from a position overlying the second support surface, a layer of fabric is applied to the first support surface, and the slurry is applied to the fabric layer.
Claim 4
Dependent Claim
44 words
The method of claim 1 wherein the first support surface converges with the second support surface from a position overlying the second support surface, a layer of fabric is applied to the second support surface and the slurry is applied to the fabric layer.
Claim 5
Dependent Claim
17 words
The method of claim 1 wherein a layer of pervious fabric is applied to both support surfaces.
Claim 6
Dependent Claim
28 words
A method according to claim 1, wherein the support surfaces are flexible belts and are vibrated by mechanical action applied to the faces thereof remote from said slurry.
Claim 7
Dependent Claim
27 words
A method according to claim 1 wherein chopped mineral fibre is incorporated in said slurry in an amount up to 3% by weight of the cementitious material.
Claim 8
Dependent Claim
26 words
A method according to claim 1 wherein said fabric or web is impregnated with water-proofing or reinforcing agents before it is applied to the core slurry.
Claim 9
Dependent Claim
14 words
A method according to claim 1 wherein said pervious fabric or web is fibrous.
Claim 10
Dependent Claim
18 words
A method according to claim 1 wherein said fabric or web is a resin-bonded non-woven glass fibre tissue.
Claim 11
Dependent Claim
98 words
A building board comprising an integral matrix of set cementitious material such as gypsum which extends from one face of the board to the other face of the board, a pervious fabric embedded in at least one of the faces, and characterized further in that at least one of said faces is a continuous film of the set cementitious material of said matrix which extends over the outer face of said fabric and which has a higher density and lower porosity than that of the portion of the matrix which lies on the inner face of the fabric.
Claim 12
Dependent Claim
98 words
A building board comprising an integral matrix of set cementitious material such as gypsum which extends from one face of the board to the other face of the board, a pervious fabric embedded in at least one of the faces, and characterized further in that at least one of said faces is a continuous film of the set cementitious material of said matrix which extends over the outer face of said fabric and which has a higher density and lower porosity than that of the portion of the matrix which lies on the inner face of the fabric.
Claim 13
Dependent Claim
64 words
A building board comprising a core of set gypsum, a pervious fabric embedded in at least one face of said core, and a continuous film of set gypsum having a higher density and lower porosity than said core extending over the outer face of said fabric; wth the proviso that said core and said film comprise a continuous and integral matrix of set gypsum.
Claim 14
Dependent Claim
64 words
A building board comprising a core of set gypsum, a pervious fabric embedded in at least one face of said core, and a continuous film of set gypsum having a higher density and lower porosity than said core extending over the outer face of said fabric; wth the proviso that said core and said film comprise a continuous and integral matrix of set gypsum.
Claim 15
Dependent Claim
17 words
A building board according to claim 10 wherein said pervious fabric or web is of mineral fibres.
Claim 16
Dependent Claim
14 words
A building board according to claim 12, wherein said mineral fibres are glass fibres.
Claim 17
Dependent Claim
19 words
A building board according to claim 13 wherein said fabric or web is a resin-bonded non-woven glass fibre tissue.
Claim 18
Dependent Claim
19 words
A building board according to claim 10 wherein the thickness of said continuous film does not exceed 2 millimeters.
Claim 19
Dependent Claim
27 words
A building board according to claim 10 wherein said continuous film includes an outermost skin of higher density and less porosity than the remainder of said film.
References Cited (Backward Citations)
GB769414A
Cited
GB772581A
Cited
US3993822A
Cited
CA993779A
Cited
US4133928A
Cited
US4195110A
Cited
US3984266A
Cited
GB1520411A
Cited
US4159361A
Cited
GB2004807A
Cited
US4288263A
Cited
US4203788A
Cited
US4344804A
Cited
US4351867A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-03-28 | 1986-09-27 | 1987-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-28 | 1990-09-27 | 1991-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-28 | 1994-09-27 | 1995-03-29 | $7700.00 | Window Closed / Lapsed |