US1808003A - Gypsum wall board - Google Patents

Description

June 2, 1931. G. NEW 1,803,003,

GYPSUM WALLBOARD FiledMay 20, 1929 INVENTOR 6057/! v5 ,4. NEW

TTORNEY Patented 0...... 2, 1931 UNITED STATES PATENT OFFICE GUSTAVE A. NEW, OF PORT CLINTON, OHIO, ASSIGNOR TO -AMERICAN GYTPSUM COM- -PANY, OF PORT CLINTON, OHIO, A CORPORATION OF OHIO GYPSUM .WALL BOARD Application filed May 20,

This invention relates to improvements in gypsum wallboard, and more particularly to an improved gypsum wall covering material and process for making the same.

In a previous application filed by me on March 26, 1928, Serial No. 264.,658, which issued as Patent No. 1,787,163 December 30, 1930, I disclosed a construction and process for manufacturing gypsum wallboard wherein the edges of the board were reinforced by a fabric strip which was folded into the desired cross-sectional contour and fed between the edges of the covering sheets during the proces of making the board, with the result that one folded portion of the strip was embedded in the plaster body and other portions extended over the edge faces of the plaster and were sealed thereto by the penetration of the plaster through the meshes of the fabric.

The purpose of the present invention is to provide an improved product having woven fabric adapted to reinforce the edges as well as an improved method for folding and incorporating the folded material into the board during the course of its manufacture, asa part of a continuous process, such as is now generally employed in the plaster board industry.

A further object of the invention is to provide plaster or wallboard wherein the fabric applied to the edges thereof assumes not only a T-form in sectional contour but is of double thickness throughout.

A further object of the invention is to provide a wallboard the edges of which are reinforced by a strip of woven fabric so folded and applied that its edges are embedded in the plaster body of the wallboard.

A further object of the invention is to'provide a novel and practical method of folding the reinforcing material into a so-called double T-form in which the edges of the unfolded reinforcing strip are brought together to form the base of the T and are thence fed into the edge of the board and embedded in the plaster or like material.

A preferred embodiment of my inviition is disclosed in the accompanying drawings, in which I v Figure 1 is a vertical cross section of one 1929. Serial No. 364,478.

edge portion of the finished board showing the disposition of the reinforcing material;

Figure 2 is a perspective view of a fragment of the finished product showing more clearly the disposition of the edge reinforcing material.

- Figure 3 is a perspective view of a strip .Of reinforcingfabric showing the successive steps in folding the strip from its initial to its final T-shape, and

Figures 4 to 8 are sectional views of the fabric strip taken at several successive points during the folding operation as indicated by lines l4 to 8-8 respectively in Figure 3.

The following is a description of the product made in accordance with my invention,

facturing the same.

As shown in Figures 1 and 2, the plaster or wallboard consists of a central core or body 1 of plaster, i.' e., calcined gypsum or other suitable material interposed between two covering sheets 2, 2 of fibrous material preferably paper of the kind and quality generally employed for the purpose. The two sheets are of the same Width and terminate flush with the edge face of the plaster body 1, so that in the absence of edge reinforcing means, the product would have all of the characteristics .of the so-called raw or trowelled edge plaster board. The finished product may be considered to be of an inch in thickness, which is the standard thickness for general purposes.

As already indicated, the edge faces of the plaster body are reinforced by woven fabric in the form of a strip 3 which has been folded lengthwise into T-form, the cross member portion 3a extending between the covering sheets 2, 2 and perpendicular thereto, and the stem portion 312' extending edgewise into the body 1, between the covering sheets 2, 2.

Thereinforcing material, as folded, is of douthroughout both portions 3a 1 should be treated with a suitable adhesive or sizing to give it a certain stiffness which will permit it to hold its shape better after folding and creasing. Due to its loosely woven 5 texture it follows that it is capable of being intimately incorporated with the plaster body 1 inasmuch as the plaster in its wet or plastic state can pass or be forced into the meshes of the fabric, thereby affording a secure bond between the two materials.

Referring now to a practical method of folding the fabric, Figures 3 to 8 illustrate the 7 various steps or folding operations through which the fabric is carried in its progress from its original flat form to its final T-shape. It will be understood in this connection, that the folding of the fabric is a continuous operation carried on in conjunction with the manufacture of the plaster or wallboard on a continuous process machine of any standard and approved design. To apply my reinforcing material such a machine could be equipped withany suitable feeding and folding evices, although the apparatus preferably used is that disclosed in a co-pending application filed by myself.

In Figure 3,the material may be assumed to advance from left to right, being fed or unwound from a roll and travelling in a substantially straight line toward the portion of the wallboard machine where the two cover sheets 2, 2 and the intermediate layer of wet plaster 1 pass between pressure rolls and are reduced to the form of the finished product.

The fabric leaves the roll as a flat strip, Figure 4, and preferably in a vertical plane. Immediately upon leaving the roll, it passes through a suitable folder which arches it transversely throughout its central portion as 9 shown in Figure 5. The strip is then led into contact with a suitable forming block or mandrel having three faces arranged at right angles to each other and around which the strlp is folded and creased, giving it the square U-shape shown in Figure 6. For con: venience the several portions of the strip may now be indicated by letters thus: a base portion a and two edge portions a, a of equal width, folded at right angles to the base portion a. Coacting with this block are suitable pressure members which act to crease the strip of material along lines I), I), thus establishing the width of the cross portion of the T-section to be ultimately formed. On leaving the forming block the strip, retaining its square U-shape, is led to another folding device which firstbrings the outer margins of the edge portions a, a of the U-shaped strip together and bends the remaining edge portions toward each other, forming a somewhat triangularly shaped section as shown in Figure 7 As the strip advances, the edge portions a, a of the strip are gradually brought go gether, the portions thereof adjacent the base a being simultaneously folded inwardly and over upon the base a. 4

The edge portions a, a are now L-shaped and located in back to back relation, thus providing a double thickness of the material throughout the entire cross section of the folded reinforcing strip as shown in Figure 8. All of the folds of the strip are finally creased so that the folded strip will hold its T-shape.

Having completed the final forming and creasing of the strip, it is then fed by means of suitable guides toward the pressure rolls of the wallboard machine and thence into position between the covering sheets 2, 2 substantially at the point where they pass between said rolls. The folded strip 3 is disposed edgewise, with the cross portion 3a of the T vertical and parallel to the plane of i the edge of the face of the wallboard and the stem portion 31) extending horizontally into the body of plaster.

It will be understood that both edges of the plaster board may be treated in the same manner by the feeding of two continuous strips into the opposite side edges thereof.

This method of reinforcing the edges of plaster board or the like maybe used to reinforce the edges of any sheet or board, with or without covering sheets, the body of which is composed of a setting or hardening material. It will be evident to, those skilled in the art that my T-shaped fabric reinforcing I strips may be used to reinforce the edges of numerous types of sheets which are made by rolling plastic material into sheet form and allowing itto harden and therefore I do not limit my invention to the specific type of sheet described in this specification and illustrated in the drawings.

Having set forth a preferred embodiment of my invention, I claim:

1. A wallboard comprising a plaster body, covering sheets on opposite sides of said body, and a strip of vwoven material folded in T- section of double thickness and applied along the edges of said bddy, with a portion thereof embedded edgewise in the body.

2. A wallboard comprising a plaster body, covering sheets on opposite sides of said body, and a strip of wovenmaterial folded lengthwise into angularly disposed portions of double thickness and applied to'the edge portions of the body so that said strip of woven material is embedded in said body.

3. A wallboard comprising a plaster body, covering sheets on opposite sides of said body and terminating at the side edges thereof, and a strip of woven reinforcing fabric folded lengthwise upon itself to form portions of double thickness arranged in T-form, one portionbeing applied parallel to the edge face of said body and the pther portion at right angles to said edge face.

45 consisting of advancing continuous sheets of covering sheets on opposite sides of said b and terminat ng at the edge faces thereof, and a strip of woven fabric folded upon itself 4. A wallboard comprising a plaster bodiy, y

to form portions of double thickness arranged in T-form, one portion being positioned in said plaster body parallel to the edge face of said body substantially flush with the edges of the covering sheets and the other portion extending into said-body at right angles to terial toward the edgesof the board, folding the advancing strip longitudinally into portions of double thickness arranged in T-form, and guiding the folded strip into the edge of the board.

6. A process of reinforcing the edges of gypsum wallboard in the course of manufacture, consisting of feeding a strip of woven fabric toward theedges of the board, folding the advancing strip longitudinally into angularly. disposed portions of doublethickness of the material, and feeding the folded strip into the edge of the board with one fportion parallel to the edges of the body 0 the board and'the other portion extending edge- 0 wise into said body.

7. A process of manufacturing wallboard consisting of advancing continuous sheets of covering material toward a pair of pressure rolls, feeding wet plaster between sald sheets in advance of said pressure rolls, feedin strips of edge reinforcing material towar the edges of said ddvancmg sheets, folding said strips lengthwise into portions of double. thickness and arranged in T-form, and- 40 guiding the folded strips between the edges of thecovering sheets with one portion embedded parallel to the edge face 0 the plaster and the other portion embedded edgewise therein. 7.

8. .A process of manufacturing wallboard covering material toward a pair of pressure rolls, feeding wet plaster between said sheets in advance of said pressure rolls, advancing a continuous strip ofwoven fabric toward the edges of said advancing sheets, folding the strip lengthwise into U-form, and thence into T-form, and guiding the folded strip between the edges of the advancing covering sheets with oneportionreinforcing the edge face of the plaster and the other portion embedded edgewisejtherein.

9. A process of manufacturing wallboard consisting of advancing continuous sheets of covering material toward 'a pair of. pressure the U-shaped strip into T-shape and creasing the same along the fold lines, and feeding the T-shape strip intothe edge of the advancing cover sheets and wet plaster.

10. A process of manufacturing wallboard consisting of advancing continuous sheets of covering material toward a pair of pressure rolls, feeding wet plaster between said sheets in advance of said pressure rolls, feeding strips of fabric toward the path of the edges of said advancing sheets, longitudinally into a creasing the same along the fold lines, thence folding and'creasin the edge portions of the U-shaped strip to orm angularly disposed folding the strip portions of double thickness arranged in T'- form, and feeding the strip thus folded between the edge of the advancing cover sheets with the cross portion ofthe T-shape strip 'reinforcing the edge face of the plaster and the stem portion extending edgewise into the plaster.

In testimony whereof I hereunto aflix my signature this 10th day of May, 1929. I GUSTAVE A. NEW.-

rolls, feeding wet plasterbetween said sheets in advance of said pressure rolls, feeding strips of fabric toward the path of the edges 7 of said advancing sheets, folding the strip longitudinally into .U-form, thence folding square U-form and

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