US1604236A - Plaster board - Google Patents

Description

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C. A. PETERS PLASTER BOARD Flled Feb 16 1925 m .www

Oct. 26 1926.

Patented Oct. 26, 1926.

UNITED STATES PATEN'I OFFICE.

'CHARLES A. PETERS, OF DOWNEY, CALIFORNIA, ASSIGNOR TO PETERS HOLDING COMPANY, A CORPORATION OF CALIFORNIA.

PLASTER BOARD.

Application led February This invention particularly pertains to a composition wall board and to the method of manufacturing same.

An object of the invention is to provide a composition board which is adapted to be employed in forming surfaces of buildings and which is so formed as to provide a surface having the character of plaster to which may be applied either a plastic coating or the fluid coatings commonly employed in the finishing and decoration of plastered walls.

Another object is to provide an effective method for manufacturing a wall board of the above character.

The type of wall board to which the present invention pertains embodies a panel or slab formed of a suitable composition which, during the course of manufacture of the board, is of plastic character, and which composition preferably includes gypsum or similar cementitious material intermixed with a vsuitable fibrous filler preferably consisting solely of asbestos fibers, but which 5 may be formed of any other fibers that will serve as a binder and reinforcement of the mass, these ingredients being admixed with water to form a plaster' which hardens when dry.

The plaster panel is' surfaced on one side with a backing sheet which may comprise paper, as commonly employed in wall board construction(` or may consist of a woven fabric, and the other or outer face of the. panel is formed with a fibrous foraminous or reticnlated reinforcing sheet preferably consisting of cotton gauze of open mesh.

In carrying out the present invention, the foraminous sheet isapplied to the surface of the plaster, preferably in such manner that the outer surface of the board will be so formed as to provide a comparatively hard and compact shell over the foraminous sheet surface to which may be applied any suitable finish coating.

A particular object of the invention is to provide means and for readily forming the roughened hard shell surface of the board.

The mode of carrying out the foregoing objects, as well as such objects, features and advantages of the invention as may' subsequently appear is hereinafter described and is illustrated by way of example in the accompanying drawings in which the several 1s, 1925. serial No. 9,608.

views depict constructions and arrangement of elements and parts whereby the invention mav be carried into effect.

Referring to the drawings the views are as follows Figure 1 is a diagram illustrating the manner of forming the board;

Figures 2, 3, 4, 5 and 6 are details illustrating more clearlythe mode of forming the board;

Figure 7 is a detail in pla-n of a fragmentary portion of the board showing the roughened outer surface of the board; and

Figure 8 is a View in section of the finished board as seen on the line 8-8 of Figure 7.

More specically, 10 indicates a long horizontally extending endless conveyor belt several which passes around direction rollers 11 and- 12 and is adapted to be advanced by any suitable driving mechanism as is common in Wall board manufacture.

A fibrous backing strip 13 of paper or similar materia-l is fed from a. roll 14 over a table 15 and between a pair of forming rollers 16 and 16', and is directed onto the upper lead of the belt 10. A suitable plastic composition 17 in a wet unstable condition, preferably formed of gypsum, asbestos fiber and water, is deposited on the strip 13 and is spread thereover as the strip advances over the table 15 and passes between the forming rollers. A facing and reinforcing strip 18 of fibrous foraminous material, such as cotton gauze or netting of open mesh and of a width corresponding to that of the backing strip is fed from a roll 19 around and under the upper forming roller 16 and is impressed by the latter onto the plastic body as itpasses between the forming rollers together with the backing strip 13. The forming rollers are spaced apart and operate .to form the advancing strip 18, plastic body 17 and foraminous strip 18 into a homogeneous panel of predetermined thickness, which passes onto the upper lead of the belt 10 and is carried forward by the latter. The upper strip 18 being foraminous a `portion of the plastic composition will be squeezed ltherethrough as it passes between the forming rollers, and accordingly, portions of the composition will adhere to the periphery of the upper roller 16. The wet plastic thus adhering to` the roller 16 is scraped off and caused to fall back upon the upper surface of the advancing panel. The panel is then passed successively between a series of airs of spaced rollers as indicated at A, B, 4and D, and is thereby subjected to a rolling and pressing action. The pairs of rollers A, B, C, and D are spaced such distance apart and the belt 10 is moved at such speed that the plastic composition of the panel will still be wet and unstable as it passes between the end pair of rollers D, although in some 'instances the end rollers D may be spaced such distance yfrom the pair of rollers C that the plastic will be partly set on passingn therebetween. The pair of rollers A are spaced apart a distance slightly less than the spacing of the forming rollers 16-16; the pair of rollers B are spaced apart a distance slightly less than the spacing of the rollers A; and the pair of rollers C are spaced apart a distance slightly less than the spacing of the rollers B so that as the panel advances through the series of pairs ot compressing rollers A, B and C, it is subjected to a series of successive impressing and rolling actions whereby the solids of the plastic composition are pressed into a more and more compact body. This compressingr action of the rollers A, B and C serves to force the more fluid portion of the plastic to the surface of the plastic body and thus coats the latter with a rich liquid mixture of gypsum and water which thickens as the panel advances between the successive pair of rollers. Portions of the liquid will adhere to the peripheries of the upper rollers of the-pairs of rollers A, B and C and is scraped off these rollers and caused to drip back onto the surface of the panel as shown in Figures 3, 4 and 5 so that when the panel passes from between the rollers C the top surface of the panel will be formed with a series of closely arranged longitudinal extending irregular ribs or ridges 20, as shown in Figures 7 and 8 which ridges will project above the foraminous sheet and will impart a roughened surface to the panel. The final pair of rollers D are employed to flatten the apexes of such ridges 2G as may project excessively from the surface of the panel, if so desired; they being spaced apart a distance slightly exceeding that of the rollers C where it is desired to flatten the ridges and render them broad, and being spaced further apart when it is desired to merely flatten the excessively high points or portions of the ridges. Where it is desired to form the board with an exceedingly rough surface the rollers D may be dispensed with or the upper roller of the pair positioned so that it will not contact the ridges. Such portion of the plastic as may cling to the uppermost roller of the pair of rollers D is removed therefrom by a scraper as indicated at 2l and may be inhibited from falling backon the surface of the panel if so desired, it being collected in a troughl formed by the scraper 21 and removed therefrom from time to time as occasion requires.

The strip of board thus formed is carried forward on the conveyor belt for such distance and for such length of time that the plastic material will set whereupon the strip is trimmed and cut into lengths in any desired manner to form panels of any desired dimensions which are subsequently kiln dried whereupon they are in readiness to be employed in forming a wall surface. ln use the panels are nailed or otherwise secured to a suitable backing or support with the roughened surface outermost, which snrface will have the appearance and character of a plastered wall and mav then be tinished and decorated in any manner applicable to the treatment of plastered walls, and

it' desired may be coated with plaster.

By forming the board in the manner set forththe foraminous strip will serve as a screen when the wet unstable plastic com position is passed between the several pairs of rollers, to prevent the coarse fibrous constituents of the plastic composition from ad hering to the compressing rollers and yet permit a portion of the fluid constituent of the plastic composition to pass through thc strip 18 and submerge the latter which fluid by reason of being Worked by the rollers will be rendered rich so that when it scts a hard dense shell will be formed on the surface ot the board in which the strip will be imbedded. However, the extent of submersion of the foraminous strip 18 in the plastic liquid may be varied as occasion may require, which is accomplished by regulatin the fluidity of the plastic composition an by adjusting the spacing of the compressing rollers. A very desirable surface is obtained by so submerging the foraminous strip in the main body of the plastic that the weave of the strip will appear in the depressions formed between the raised ridges 2O as shown in Figure 7.

In practice, toform the finished board of a thickness of about three-eightlis of an inch the forming rollers 16-16 are spaced apart about seven-sixteenths of an inch, and the pairs of rollers A, B and C are spaced respectively thirteen-thirty seconds, threeeighths and eleven-thirty seconds inches apart, while the end rollers D are spaced about three-eighths of an inch apart.

In the preferred embodiment of the invention a thread-like fibrous material such as asbestos fibers is incorporated in the plastic composition so that the ends of some of the fibers will be caused to project into the interstices formed by the mesh of the foraminous strip 18 on pressing the strip onto the plastic, as described, so that the bond between the plastic andthe strip will be increased A 'By working the wet plastic body in ,the manner set forth the portion of theplaster carrying the fibrous filler and which extends between the backing sheet Vand the forami.- nous sheet will be comparatively soft when dry while the outer portion thereof will be formed with a hard shell as before stated.

While I have shown and described the use of three sets of compressing rollers A, B ard C, it is to be understood that satisfactory results may be obtained by employing either a lesser or greater number of such rollers, and that while I have shown and described a specific embodiment of the invention I do not limit myself thereto but reserve the right to all such variations and modifications as properly fall within the scope of my invention and the terms of the following claims.

I claim l. A Wall board comprising a plaster panel including a relatively soft body formed with a hard surface, and a sheet of netting embedded in the hard surface portion of the panel through the interstices of which project and overthe mesh of which netting extends portions of the plaster; the hard surface of the plaster being formed throughout with ridges.

2. A plaster board having a fibrous netting on the surface thereof through which project bodies of plaster forming the surface of the board throughout the entire area thereof with ridges.

3. A wall board comprising a plaster panel, a backing sheet surfacing one side of said panel, and a sheet netting on the other side of said panel through which project irregular bodies of plaster forming the board throughout the area of one side thereof with a roughened surface of plaster. j

4. A wall board comprising a panel formed of plaster having the back portion of its thickness formed relatively soft and provided with a hard shell front surface, a fibrous netting on the front surface through which project irregular bodies of the plaster whereby the front surface of the board is formed throughout the area thereof with a roughened surface of hard plaster, and a backing sheet surfacing the back portion of said panel.

5. The method of forming a plaster board consisting in coating a backing sheet with a wet unstable plastic composition, embedding a sheet of netting in the surface of the plastic body under pressure, subjecting the surface of the plastic body to a rolling and pressing action while wet so as to squeeze the more liquid content of the plastic composition through the interstices of the sheet, the front surface of the board being formed throughout the area thereof with a roughened surface of plaster, and then allowing the plastic to set and dry;

6. The method of forming a plaster board consisting in coating a backing sheet with a wet unstable plastic'composition, embedding a foraminous sheet in the surface of the plastic body under pressure, subjecting the surface of the plastic body to a rollingrv and pressing action while wet so as to cause a thin portion of the plastic to rise through the interstices of the sheet, removing portions of the thin plastic and causing such portions to drip back on the surface of the plastic body so as to form ridges thereon, and then allowing the plastic to set and dry.

7. The method of forming aplaster board` consisting in coating a backing sheet with a- Wet unstable plastic composition, embedding a foraminous sheet in the surface of the plastic body under pressure, subjecting the surfac of 'the plastic body to a rolling and pressing action while wet so as to cause a thin portion of the plastic to rise through the interstices of the sheet, removing p0rtions of the thin plastic and causing such portions to drip back on the surface of the plastic body so as to form ridges thereon,

subjecting the ridges to a attening action,

snd then allowing the plastic to set and 8. The method of forming a plaster board consisting in coating a backing sheet with a wet unstable plastic material including in its composition gypsum, fibrous substance and water; placing a foraminous sheet on the surface of the plastic body, subjecting the plastic body while soft and wet to a series o f successive impressing and rolling actions to bring a rich fluid mixture of the ypsum and water to the surface thereof through the foraminous sheet, and allowing the plastic to set and dry.

CHARLES A. PETERS.

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