US1556575A

US1556575A - Plaster board

Info

Publication number: US1556575A
Application number: US504755A
Authority: US
Inventors: Morgan K Armstrong
Original assignee: BEAVER PRODUCTS Co Inc
Current assignee: BEAVER PRODUCTS Co Inc; BEAVER PRODUCTS COMPANY Inc
Priority date: 1921-10-01
Filing date: 1921-10-01
Publication date: 1925-10-13
Anticipated expiration: 1942-10-13

Description

Oct. 13, 1925 M. K. ARMSTRONG PLAsTER BOARD Filed oen-1.' 192;

PatentedA '13', '-1925,

UNITED .sra-TES;

PATENT oFFifcE.

IOBGAN' X. `ARMSTRONG, 0F WINNETKA, IiLINOIS, ASSIGNOR, BY MvEBNE ASSIGN- HENTS, 10 THE BEAVER PRODUCTS COMPANY, INC., A CORPORATION Ol' YORK.

rLAs'rmi Bonnin.

appii'uon ma october 1, 1921. semi in. 504,155.

To all whom/t may cancer/n.:

Beit known that MORGAN K. ARMSTRONG, a citizen of the United States, and a resident of the city of-Winnetka, county of Cook, State of Illinois, has invented an Im rovement in Plaster Board, of which the ollow- .ing is a specification. p

This invention relates to composite board, known generallyl as plaster board. Among other objects, t e invention is .intended to provide improved boards having plaster receiving surfaces of uniform characteristics, wherebythe lastered or otherwise coated surfaces will e of uniform and improved quality` with a decreased' tendency to crack at the joints between adjacent boards.

.Another object is to provide a board which will retain its .shape in a plaster w ceiling or analogous location.

The invention consists in the novel combinations and constructions to be hereinafter described and claimed for carrying out lthe above stated objects and such other objects as will appear from the description and claims. y

The invention is illustrated in a preferred embodiment in the accompanying drawing wherein: v

Fig. 1 is a fragmentary perspective view of a plaster wa l. employing a composite board embodying features of this invention.

Fig. 2 is an enlarged section of a plaster boar A Like characters of reference designate like parts in the several figures of the drawing. In the illustrative embodiment shown in the drawings,'the composite board 10, comprises a substantially rigid body, or core 11, having covering material 12 on one or both faces thereof. TheV body 11 may be of any suitable material such as plaster, to which the coveringmaterial 12 is adapted to adhere.

The covering material is preferably of a fibrous character, such as heavy paper which is manufactured or treated so as to retard for a given period of time, the penetration and the faces of which of Water or moisture,

laster or the like.

are adapted to adhere to Preferably the cover s plurality of plies, the outer plies, being unsized or adapted to adhere to or receive plaster, and the intermediate plies being ter body, may

' the plaster or eet is made of a.

treated or adapted to preventA the penetration of moisture through the sheet for a 66 given period'of time. For instance, in thev manufacture of a paper covering material, the outer ply or plies on the outside of the sheet and also if desired, the outerfply or plies on the inside of the'sheet next the' plaswhich isunsized or slack-sizec and th'e intermediate lies may be made from stock which is sized) to prevent'l the penetration of moisture by a suitable sizing such as resin. The term slack-sized is used to characterize fibre stock which is 4treated by or contains a compound which neutralizes any sizing which may exist in the stock and maintains the stock in unsized condition. The .number of plies in the paper may be varied in order to provide a sheet of the required thickness and strength and inforder to provide unsized and sized plies lof suitable thickness and having the proper characteristics. For instance, it is desirable that the unsized outer layer be of sufficient thickness to properly and firmly retain or adhere to plaster or other composition em'- ployed. On the other hand, it is desirable that the unsized ply or plies, particularly those on the outside surface of the board, be thin enough or their water-absorbing capaci- '.ty sufficiently limited that they will not ab- .sorbtoo great a quantity of water as to interfere with the cr stallization of the plaster. The interme iate sized ply or plies should be so sized that they will prevent the penetration of any substantial quantity of moisture through the paper for a length of time sufficient to permit the convenient handling of the board during manufacture and to permit at least a partial setting of the-plaster core and, after the hoard is used, `to permit an adequate setting or drying of other surfacing applied to the board.

In the illustrative form, shown in Fig.' 2, the covering material, which has been drawn on an exaggerated scale to illustrate its structure, is a paper sheet, composed of five be made from

paper stock plies

13, 14, 15, 16 and 17, the middle three,

nuinber of sized and unsized plies or the total number of plies in the paper maybe varied to suit particular requirements.

In Fig. 1 is shown an illustrative Wall construction, employing a board embodying the invention above described. The Wall comprises the) usual supporting structure 18, to which the plaster hoard is nailed or otherwise secured. To the surface of the board is applied one or more layers 19 of plaster or other surfacing in the usual manner. The first coat of plaster adheres to the unsized surface of the covering material of the board, and the moisture retarding characteristics of the underlayer of the covering sheet prevent any Water, particularly the Water of crystallization content, from being absorbed o-ut of the plaster surfacing into the paper and plaster core of the board. This insures a uniform and simultaneous drying and setting of the plaster orother surfacing on adjacent boards and the consequent uniform contraction of the plaster surfacing on adjacent boards.

The unsized outer layer of the covering sheet is so thin that even if its Water-absorbing properties vary for different boards, this factor Will not appreciably interfere with the uniform setting and drying of the surfacing. But it is seldom possible to obtain Wholly unsizedpaper for covering sheets which is sufliciently uniform in its effect upon the plastered surface that the plaster on adjacent boards Will act alike. The

' water-absorbing properties of and the speed at which water penetrates unsized coverino paper of this type, frequently vary to suoli an extent that the plaster surface in one board will set and dry lon before the surface on the adjacent boar has set. This causes uneven and irregular contraction of the plastered surfaces and results in cracks at the joints between the boards. Frequently the Water of crystallization content in the plaster surface is partially absorbed by the paper and plaster core of the board, leaving the plaster surface chalky and Weak when it is dry.

The improved board may be used on ceilings and 1n similar situations and plastered over Without the danger of sagging. The Water from the plaster cannot appreciably penetrate -the paper and enter the plaster core to soften it and permit it to sag or Warp.

The illustrative plaster board may be made in any appropriate manner. For instance, a bottom cover-sheet may be led past a chute which deposits plaster thereon, after which a top sheet is placed upon the plaster and the board thus formed passed between a pair of rolls which firmly unite the cover sheets with the plaster. f desired the margins of the bottom sheet may be progressively folded up and over the margins of the top sheet as shown at 20, Fig. 1, a layer 21 of plaster being employed to firmly cement the folded margins in place. The provision of a sizedv fpaper having unsized surfaces results in a rm bond between the margins of both sheets and the plaster layer 21.

As will appear to those skilled in the art, the invention is applicable to composite boards and the like made of materials which are functionally equivalent to, but specifically diferent from the plaster and paper referred to above. Obviously, the invention is not limited to the particular embodiment illustrated but may be variously modified. Moreover, certain features may be advantageously employed in various combinations and subcombinations and need not all be ,used conjointly.

`l claim:

1. A composite board, comprising in combination a body of plaster o-r the like and covering material adhering to the surface thereof, said covering material having both surfaces of a character to receive and adhere to substantial penetration of moisture therethrou h.

2L composite board comprisin in combination, a substantially rigid ody and covering material adhering thereto, said material having unsized surfaces and a sized center.

3. A composite board comprising, in combination, a substantially rigid body and covering material adhering thereto, said covering material having absorbent surfaces and a moisture retarding center.

4. A composite board comprising, in combination, a body of plaster or the like and covering material therefor adapted to retard the penetration of moisture throu hthe same, the inner and outer surfaces o said material being adapted to adhere to plaster.

5. A com osite board comprising, 1n combination, a ody of laster or the like, covering material there or consistin of a lurality of plies, an intermediate p y of w ich is sized, and the outer plies being adapted to adhere to plaster.

6. A composite board comprising, in combination, a body of plaster or the like, a paper covering sheet therefor consisting of a plurality of plies, the outer plies being unsized and an intermediate ply being sized.

7 A composite board comprisin in combination, a body of plaster or the like, paper coverin sheets therefor consisting of a plurality o plies, the plies at the exposed surface of the board being unsized and certain inner plies being sized.

8. 'A composite board comprising, in combination, a body of plaster or the like, fibrous covering material therefor havin an` outside unsized layer and an inner sized layer.

9. A plaster board comprising in combif' i n 1,556,515

nation a plaster body; covering material adhering to said laster body,v said covering material being olded around the edges of said plaster body to envelopethe same, and having its margins arranged in overlapping relation, the overlying margin being cemented in place by an intervening layer of plaster; said overlapping margins being treated to retard moisture penetration, but having their surfaces adjacent said layer of plaster treated to cause them firmly to' adhere t0 said layer of plaster.

10. A p-laster board, comprisinfv in combination, a plaster body; covering material adhering to said plaster body and treated to retard moisture penetration; said covering material being folded around the edges of said plaster body to envelope uthe same and having its margins .arranged in overlapping relation, the overlying margin being cemented in place by an intervening layer of plaster; said margins having their surfaces adjacent said plaster layer unsized to cause said plaster layer to adhere firmly thereto.

l1. A plaster board, comprising in combination, a plaster body; lcovering material adhering to said plaster body, and covering v its vfaces and reinforcing the same; said covering material having surfaces to which plaster readily adheres but treated to retard moisture penetration.

In testimony whereof, I have signed my nameto this specification.

MORGAN K. ARMSTRONG.