US1578250A - Process of making plaster board - Google Patents

Description

March 3o 1926. 1,578,250

M. K. ARMSTRONG l PROCESS o MAKING PLASTER BOARD Original Filed Dec. 12, 1921 2 Sheets-Sheet 1 March 30 1926. 1,578,250

M. K. ARMSTRONG PROCESS OF MAKING PLASTER BOARD Original Filed Dec. 12, `1921 2 Sheets-Sheet 2 Y. .NNY my my Patented Mar. 30, 1926.

\ UNITED STATES PATENT OFFICE.

MORGAN K. ARMSTRONG, OF HAMPTON, VIRGINIA.

PROCESS OF MAKING PLASTER B OARD.

To all whom 'it may concern:

Be it known that I, MORGAN K. ARM- STRONG, a citizen of the United States, and a resident of Hampton, in the county of Elizabeth City and btate of Virginia, have invented certain new and useful Im rovements in Processes of Making Plaster oard; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

This invention relates to an improved process for making plaster board, and consists of the matters hereinafter described and more particularly pointed out in the appended claims.

The object of the invention is to provide a novel and improved process for the manufacture of plaster board of the kind described in an application executed of even date herewith, and comprising a plaster body and to and bottom covering sheets of paper or ot er fibrous material, vwith strips or bands of a nailing mixture forming the body at the edges of the board and finishing the edges thereof. In order to illustrate my process, I accompany the application with drawings showing a machine or apparatus by means of which my improved process ma be carried out.

n the drawings Figure 1 is a diagrammatic view of a longitudinal section through the apparatus. igure 2 is a view representing a top plan view of Fig. 1.

Figure 3 is a view representing on an enlarged scale a transverse section throughv Figure 2 in a plane indicated by the line 3-3 of Figure 2.

Figure 4 is a view representmg a horizontal section through Figure 3 in a plane indicated by the line 4-4 of Figure 3.

Figure 5 is a view representing on an enlarged scale a section through Figure 1 1n the plane indicated by the line 5-5 lof F 1g. 1.

Figure 6 is a view representing a trans- 1 verse section through the finished board.

My improved process is a contlnuous process and as to its general features is like the well-known continuous process by means of which plaster board, comprlsing top and bottom covering sheets and an mterposed ,j Application filed December 12, 1921, Serial No. 521,577. Renewed July- 29, 1925.

ly spread over the advancing bottom sheet, y

and as it reaches the rollers13, 14 a top sheet 16, fed from a roll 17over and about tension rollers 18,'and then about and under the top roller 13, is laid on and adhered to the layer,

of plaster. From the rollers 13, 14 the board thus made is fed over an endless conveyor belt 19, which is made of sufiicient length to permit the setting of the plaster before the strip of board reaches the end of said conveyor. The board is then cut to the desired lengths and is put into kilns to dry.

In the present process, in addition to the layer of plaster material, there is laid on the advancing bottom sheet the bands or strips of' a nailing mixture which is to form the edge of the board. This mixture may be of any suitable composition, possessing the requisite properties of a nailing miXture,- that is to say, a plastic mixture which, when dry, may be Vpe-netrated by a nail withoutdisintegration yor cracking. Such a mixture may be made from tar, sawdust or other fibrous material and clay, mixed while hot.

In carryingy out the process, and preferably, I make a board of double the intended width, which may be sawed or cut throu h the middle' to provide two lengths of lie board. To this end,'in manufacturing the board according to the process as carried outon the apparatus illustrated herein, I apply to the advancing bottom covering sheet 11, bands or strips of the plaster nailing mixture 20, 20 at the edges of the bottom sheet,

and an intermediate band of double width I 21 along the longitudinal middle line of the sheet. The strips or bands of the plastic nailing mixture are applied to the advancing bottom sheet in the positions illustrated in- Figure 2 by any suitable means. As shown, I have provided hoppers 20, 20, and 21,

to which the soft plastic nailing mixture is mixture are driven in any suitable manner (not shown) By this means and in this way the three bands of nailing mixture are laid on the advancing sheet, the surface of the sheet between said bands being left free and exposed.

The plaster to form the vmain body of the board, instead of being applied to the Whole width of the bottom sheet 1l, as heretofore, is applied to the intermediate Widths or spaces 25,l 26 (see Fig. 2), being directed thereon from suit-able hoppers, not shown, by means of belts 25, 2U, located at either side of the machine. The plaster is spread over the sheet in the spaces 25, 26, intermediate the bands, to form the main body parts 25", 26" of the board and when the top sheet is applied by the pressure of the roller 13 in the usual manner, said top sheet` is adhered not only to the main plaster body 25", 26" but also to the nailing mlxture bands 20, 21, 20. As the body with its covering sheets passes between the rollers 13, 14, the plaster bodies 25", 26" are forced into intimate contact at their edges with the proximate edges of the several bands 20, 21, 20, of nailing mixture so as to provide an intimate union and bond between the two different characters of material forming the body of the board.

In order to hold the said nailing mix bands in position and to prevent the plaster mix of the main body from being forced over the top of said bands, I provide a pluraiity of mould plates 27, 27 and 28, 28, the first two named being directed along the inner edge of the outer nailing ' mixture bands 20, 20, and the second two being located at either side of the central nailing mixture band 21. These mould plates are preferably made of glass and are supported in any convenient mannen-as forl example, by the bars 2 9, 29k which extend transversely of the machine and are' supported from the platform 12 by means of straps 30 (see Fig.

3). The mould plates are mounted in brackets 31, each of which is secured to its bar 29 by means of a setscrew,--said bracket being slidable on the bar so as to be capable of lateral adjustment thereon to adjust its position in accordance with the width of nailing mixture band that is to be applied. The front ends of said plates are curved as indicated at 32, to fit the bottom surface of the top roller 13, and have ends or points 33 that terminate short of the vertical plane through the axes of the rollers 13, 14. The mould plates are attached to the brackets 31, as indicated, in such manner that they may 'be adjusted longitudinally so as to bring the the mould plates prevent the plaster from coming into contact with the nailing mixture bands, said plates, as will be understood, being adjusted to bear lightly on the top surface of the advancing bottom sheet. As the `points 33 ofy said mould plates terminate short of thevertical plane through the axes of the rollers 13, `14,-that is to say, short of the narrowest space separating they'sur. faces of said rolle1's,-just before the body is reduced to the final intended thickness by passing between the rollers,vtlie plaster of the body parts 25", 26" is forced laterally outward beyond said points against `the proximate edges of the nailing mixflliands 20, 21, 20, thus bringing about a forcing together of the several kinds of plastic material composing thebody into intimate,l euga-gement at the point when the greatest pressure is exerted, with the result that a bond is afterwards formed between them when the plaster sets.

In order to smooth up and makelrne the outer edges of the two outermost nailing mixture bands 20, 20, it is preferable to provide a scraper or shoe 34, which is supported in such manner as to engage the edges of the advancing board as the board passes through the vertical plane of the diameters of the rollers 13, 14. Said shoes as shown, are attached to the straps which support the forward bar 29.

In order to provide a bevel at the edges of the hoard, one of the rollers (as shown the top roller) is provided with a coniform cnlargement 13, and in the case where the board is made of double width, as illustrated herein, the same roll is 'provided with a coniform enlargement 13" at the middle,- the cones being oppositely disposed as shown in Figure 5.

After it is formed as above described, the board is carried over the endless conveyor 19, in the usual manner and allowed to dry or set, after which it is severed transversely into the desired lengths, and longitudinallA f into the designed two Widths iof board, such as shown in Figure 6. The board isthen dried in suitable kilns in a familiar manner. This completes the process.

The resulting board has true, straight edges which may be freely handled and l nailed in position without danger of marring or breaking the board at or near said edges.

I claim as my invention:

1. The continuous pnocess ofl making plaster board, which consists ot' advancing a bottom covering sheet of fibrous material of the Width of the board to be made; of superimposing upon said sheet along its edges l ribbons of a plastic nailing mixture, said ribbons being substantially rectangular in cross-section and of predetermined width and thickness; of spreading a plastic gypsum mixture over said sheet intermediate said ribbons; of confining said gypsum mixture to prevent its overflow on said ribbons while it is being spread; of superimposing a top covering sheet of fibrous material of the same width as that of'the bottom sheet on said several plastic mixtures; and of applying pressure to the full width of said top sheetto firmly adhere it to the top surface of the said several mixtures comprising the body of the board, at the same time forcing the intermediate plastic mixture laterally outward at its edges into intimatevcontact with the proximate edges of said ribbons.

2. The continuous process of m-aking plaster board, which consists of advancing a bottom covering sheet of fibrous material of double the width of the board to be made; of superimposing upon said sheet along its edges and along its median line ribbons of a plastic nailing mixture, said ribbons being substantially rectangular 1n cross-section and of predetermined Width and thickness and the ribbonl alon the median line being double the width o the ribbons along the edges; of spreading a plastic gypsum mixture over said sheet intermediate said ribbons; of confining said gypsum mixture to prevent its overflow on said ribbons while i-t is being spread; of superimposing a top covering` sheet of fibrous material of the same width as the. width of said bottom sheet on said plastic mixtures; and of applying pressure to the full width of said top sheet to firmly adhere it to the top surfacevof said several plastic mixtures comprising the body of the board, and at the same time forcing the plastic mixture intermediate said rib-- bons laterally outward at its edges intoA intimate contact with the edges of said ribbons.

3. The continuousv` pnoeess. of making plaster board, which consists of advancing a bottom covering sheet of fibrous material of the Width of the board to be made ;of superimposing uponsaid sheet along its edges ribbons of a plastic nailing mixture, said ribbons being substantiallyl rectangular in cross-section and of predetermined Width and thickness; of spreading a plastic gypsum mixture over said sheet intermediate said ribobns'; of confining said gypsum mixture to prevent its overflow on said ribbons while it is being spread ;l of superimposing a top covering sheet of fibrous material of thc same width as that of the bottom sheet -on said several plastic mixtures; of applying pressure to the full width of said top sheet to firmly adhere it to the top surface of the said several mixtures'comprising the body vward at its' edges into intimate contact with the proximate edges of said ribbons; and of facing the outer edges of said ribbons to form and smooth the edges of the board;

4. The continuous process of making plasf ter board, which consists of advancing a bottom covering sheet of brous material of the width of the board to be made; of superimposin upon said sheet in predetermined lines rib ons of a plastic mixture capable of being given a definite form in cross-section when in a plastic state; of spreading a plastic mixture of a different consistency over said sheet intermediate said ribbons; of confining said intermediate mixture to prevent its overfiow on said ribbons; of superimposing a top covering sheet of fibrous material of the same Width as said bottom sheet on saidseveral plastic mixtures; and of applying pressure to the full width of said top sheet to firmly adhere it to the top surface of said several plastic mixtures comprising the body of the board, and at the same time forcing the intermediate plastic mixture laterally outward at its edges into intimate contact with the proximate edges of said ribbons to join said several plastic mixtures into a single body for the board.

5. The continuous process of making plaster board, which consists of advancing a bottom covering sheet of fibrous material of the width of theboard to be made; of. superim- .posing upon said ysheet along its edges ribons of a plastic nailin mixture, said ribbons being .substantial y rectangular in cross-section and of predetermined width and thickness; of spreading a plastic gypsum mixture over said sheet intermediate said ribbons; of superimposing a top covwidth as that of the bottom sheet`on said several plastic mixtures; and of applying pressure to the full width of said top sheet Ito firmly adhere it to the top surface of the said several mixtures comprising the erlng sheet of fibrous'material of the same body of the board, at the same time ,forcing the intermediatel plastic mixture laterally outward at its edges into intimate contact with the proximate edges 0f said ribbons.

6. Thecontinuous rocessrof making plaster board, which consists of advancing a bottom .coverin sheet of fibrous material of double the wldth of theboard to be made; of superimposing upon said sheet along its edges and along its median. line ribbons of a plastic nailing mixture, said ribbons being su stantially rectangular in cross-section and of predetermined width and thickness and the ribbon alon the median line being double the width o the ribbons along the edges; of spreading a plastic gypsum mixture over said sheet intermediate said ribbons; of superimposing a top covering sheet ot fibrous material of the same Width as the width of said bottom sheet on said plastic mixtures; and of applying pressure to the e full width of said top sheet to firmly adhere `outward at its edges into intimate contact with the edges of said ribbons. v

7. The continuo-us process of making plaster board which consists of advancing a bots tom covering sheet of fibrous material of the width otthe board to be made; ot superimposing upon said sheet along its edges ribbons ot' a plastic nailing mixture, said ribbons being substantially rectangular in cross-section and otl predetermined width and thickness; of spreading a plastic gypsum mixture over said sheet intermediate said ribbons: of superiml'iosing a top covering sheet of fibrous material of the same width as that ot' the bottom sheet on said several plastic mixtures; of applying pressure to the full width o't said top sheet to firmly adhere it to the top surface of the said several mixtures comprising the body of' f the board, at the same time forcing the intermediate plastic mixture laterally out- Ward at its edges into intimate contact With the proximate edges of said ribbons; and of facing the outer edges of said ribbons to form and smoooth the edges of the board.

8. The continuous process of making plaster board, which consists of advancing a bottom covering sheet of fibrous material of the width` of the board to be made; of superimposing upon said sheet in predeterminedy aol sheet on said several plastic mixtures; and

ot applying pressure to the full Width of said top sheet to firmly adhere i-t to the top surface of said several plastic mixtures comprising the body of the board, and at the same time forcing the intermediate plastic mixture laterally outward at its edges into intimate Contact with the proximate edges of said ribbons to join said several:.plastic mixtures into a single body for the board.

In testimony that I claim the :foregoing as my invention, I aix my signature this 11th day of July, A. D. 1921. i

MORGAN K. ARMSTRONG. l

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