초록 ▼

A ceiling tile of gypsum and cellulose fibers formed into a board by initially mixing the fibers and gypsum in a water-based slurry that is felted and thereafter pressed and dried with a desired board thickness, the dried board being processed to form a plurality of holes in a face thereof through a

A ceiling tile of gypsum and cellulose fibers formed into a board by initially mixing the fibers and gypsum in a water-based slurry that is felted and thereafter pressed and dried with a desired board thickness, the dried board being processed to form a plurality of holes in a face thereof through at least the majority of the thickness of the board, the collective volume of the holes being sufficient to reduce the weight of the board by at least 10% and increase the NRC exhibited by the board over that which would otherwise be found in a board of the same composition without such holes.

대표청구항 ▼

What is claimed is: 1. A ceiling tile having a rectangular shape and having nominal dimensions of approximately between 2 foot by 2 foot and 5 foot by 5 foot, the tile being formed of gypsum and cellulose fibers, the gypsum and cellulose fibers being formed into a board by uniformly mixing the fibe

What is claimed is: 1. A ceiling tile having a rectangular shape and having nominal dimensions of approximately between 2 foot by 2 foot and 5 foot by 5 foot, the tile being formed of gypsum and cellulose fibers, the gypsum and cellulose fibers being formed into a board by uniformly mixing the fibers and gypsum in a water-based slurry that is felted and, thereafter, pressed and dried with a desired board thickness, the dried board being processed to form a plurality of holes in a face thereof by removal of board material through at least the majority of the thickness of the board, the collective volume of the holes and corresponding removed material being sufficient to reduce the weight of the board by at least 10% and to increase the NRC exhibited by the board over that which would otherwise be found in a board of the same composition and devoid of holes, said holes being cut from a side of the board associated with said face and being blind at a side opposite said face, said board being made of cellulose fiber and gypsum, in a ratio of between about 8% to about 30% weight, which has been calcined in a water slurry under pressure and thereafter recrystallized in the voids and crevices of the fiber to intimately bond the particles of gypsum with the cellulose fibers such that sifting from said cut holes of loose gypsum is reduced when the tile is thereafter handled, shipped, installed or serviced. 2. A ceiling tile as set forth in claim 1, where said board is covered with a porous fabric. 3. A ceiling tile as set forth in claim 1, wherein said board is covered with a porous fabric laminated on a side opposed to the side on which said imperforate sheet is laminated. 4. A generally planar ceiling tile for a suspended ceiling having a rectangular shape in plan view and being relatively thin in a vertical direction in comparison to its planar dimensions, the tile having a structural body formed of a homogeneous composite of gypsum and cellulose fibers, in a ratio of cellulose fiber to gypsum of about 8% to about 30% by weight, that, together, comprise substantially at least 90% of the weight of the body, the body being formed in a felting type process whereby the cellulose fibers are uniformly substantially randomly distributed and oriented through the body such that the body exhibits substantially the same mechanical properties in both directions of the rectangular tile profile, the body having a uniform thickness across a major part of the area spanned by its rectangular shape, a plurality of spaced blind holes cut into the body, the holes being on a side of the body adapted to face the interior of a room in which the tile is installed and being distributed across substantially the full area of said side, said holes being of sufficient size and number to reduce the weight of the body by at least 15% and to increase the NRC of the body, the composite body being a product formed by calcining gypsum in a slurry under pressure and thereafter recrystallizing the gypsum in situ on and in the cellulose fibers whereby sifting from said cut holes of loose gypsum particles is reduced when the tile is handled, shipped, installed or serviced. 5. A ceiling tile as set forth in claim 4, wherein said holes are blind as a result of being drilled to a depth of less than a thickness of the structural body. 6. A ceiling tile as set forth in claim 4, wherein the perimeter of the structural body is cut to form a rabbeted edge such that the face formed with said holes is slightly smaller in profile than the full planar profile of the structural body and the perimeter area of the body lies in a plane between said face and an opposite rear face of the body. 7. A ceiling tile as set forth in claim 4, wherein a porous fabric is laminated on said face, said porous fabric being effective to increase the NRC of the tile. 8. A ceiling tile as set forth in claim 4, wherein said holes are cut through the full thickness of the structural body. 9. A ceiling tile as set forth in claim 8, including an imperforate web laminated on the side of said structural body opposite said front side. 10. A ceiling tile as set forth in claim 9, wherein said imperforate web is a paper stock.