Improvements relating to Composite Boards or Slabs for Building Purposes.
Year: 1893

page_text: Date of Application, 23rd Oct., 1893
Complete Specification Left, 23rd July, 1894-Accepted, 1st Sept., 1894
PROVISIONAL SPECIFICATION.
Improvements relating to Composite Boards or Slabs for Building
Purposes.
I, ADOLF MACK, of the Firm of A. & O. Mack, Manufacturers, of
Ludwigsburg, in the Kingdom of Württemberg, do hereby declare the nature of
this invention to be as follows:-
This invention relates to composite boards or plaster boards of the type described
in the Patent Specification No. 17130 of 1886, and has for its objects, to render
such boards practically unbreakable during long transport or under heavy loads,
and to render them water or weatherproof.
For increasing the resistance of the boards against breaking I provide them with
one or more layers of woven fabric embedded in the plastic material, which may
be done in the following manner :
I place on an iron base plate a rectangular frame provided with a longitudinal
partition; two adjoining sides of said frame being fixed and rigidly connected with
each other, while the two other sides and the partition are detachable. The base
plate and frame form together an open rectangular mould, the bottom of which
may be lined with a sheet of asphalte-felt, or of zinc or indiarubber. A portion
of the semi-liquid plastic mass is now poured into the mould and distributed over
the bottom to the height varying between and 1 inch, according to the thickness
of the composite board to be produced.
Into this plaster of Paris or other plastic mass 1 press a tissue of vegetable
stalks, (instead of loose stalks as before), which in the case of thin boards has the
width of the mould, thus forming a single layer, but in the case of thick or hollow
boards, has slightly more than twice the width of the mould in order to form the
oval core of the boards.
In the case of thin boards, I pour on the woven fabric the semi-liquid plastic
mass described in the Patent No. 17130%, until it is flush with the top of the
ledges forming the sides of the mould, and then scrape the surface of the mass, so
as to make it even.
In the case of thick composite boards, the ends of the woven fabric are allowed
to project over the longitudinal sides of the double mould and over the partition,
the plastic mass is then poured upon the fabric contained in the mould, the ends of
the fabric are then folded down upon the plastic mass, and united so as to form an
oval core, and finally the mould is filled with plastic mass up to the height of the
sides, and the surface is scraped even.
In making hollow boards I insert into the mould after the woven fabric bas been
laid in, the longitudinal rods necessary for forming the hollow spaces, I then fill
the mould with plastic mass until it reaches about inch above the said rods,
subsequently I fold the ends of the woven sheet inward and unite them, so as to
form an oval core. Finally I fill the mould with the plastic mass up to the height
of the sides, and draw out the said rods, so as to leave in the mass corresponding
holes.
To make weather- and waterproof boards, I use specially prepared gypsum, in
addition to the ordinary burned and ground gypsum mentioned in the Patent
No. 17130. The latter is burned at a temperature of about 150° C. and still
contains about 10 per cent. of water, whereas the special kind of gypsum is burnt
or calcined in a kiln to red heat, thereby losing nearly all its water and acquiring
or its subsequent treatment the properties of cement, that is to say, it becomes
low-setting, waterproof, and weatherproof.

page_text: This slow-setting cement-like gypsum mix with ordinary burnt quick-setting
gypsum in about equal parts, and proceed as described in the said Patent Speci-
fication (page 3, lines 8-15 of the printed copy) or as described in the first part
of the present Specification.
Dated this 20th day of October 1893.
COMPLETE SPECIFICATION.
Improvements relating to Composite Boards or Slabs for Building
Purposes.
I, ADOLF MACK, of the Firm of A. and O. Mack, Manufacturers, of
Ludwigsburg, in the Kingdom of Württemberg, do hereby declare the nature of
this invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
This invention relates to composite boards or plaster boards of the type described
in the Patent Specification No. 17130 of 1886, and has for its objects, to render
such boards practically unbreakable during long transport or under heavy loads,
and to render them water or weatherproof.
For increasing the resistance of the boards against breaking, I provide them
with one or more layers of woven fabric embedded in the plastic material, which
may be done in the manner hereafter described and illustrated by the accompanying
drawings, of which Figs. 1 and 2 are vertical cross sections, while Fig. 3 is a
horizontal section.
I place on an iron base plate A a rectangular frame provided with a longitudinal
partition; two adjoining sides of the said frame (a and b) being fixed and rigidly
connected with each other, while the two other sides d, e, f, and the partition c
are detachable. The base plate and frame form together an open rectangular
mould, the bottom of which p may be lined with a sheet of asphalte-felt, or of
zinc or indiarubber. A portion of the semi-liquid plastic mass is now poured
into the mould and distributed over the bottom to a height varying between
and 1 inch, according to the thickness of the composite board to be produced
(Figs. 1 and 2).
Into this plaster of Paris or other plastic mass, I press a tissue of vegetable
stalks, (instead of loose stalks as before) which in the case of thin boards has the
width of the mould, thus forming a single layer, but in the case of thick or hollow
boards, has slightly more than twice the width of the mould, in order to form the
oval core of the boards.
In the case of thin boards, I pour on the woven fabric the semi-liquid plastic
mass described in the Patent Specification No. 17130, until it is flush with the
top of the ledges forming the sides of the mould, and then scrape the surface of
the mass, so as to make it even.
In the case of thick composite boards, the ends m, n of the woven fabric are
allowed to project over the longitudinal sides of the double mould and over the
partition, the plastic mass is then poured upon the fabric contained in the mould,
the ends of the fabric are then folded down upon the plastic mass, and united so as
to form an oval core, and finally the mould is filled with plastic mass up to the
height of the sides, and the surface is scraped even.
In making hollow boards, I insert into the mould, after the woven fabric m-n
(Fig. 2) has been laid in, the longitudinal rods g, h, i, necessary for forming the
hollow spaces, I then fill the mould with plastic mass, until it reaches about + inch
above the said rods, subsequently I fold the ends m and n of the woven sheet
inward and unite them, so as to form an oval core, as shown on the right hand
of Fig. 2. Finally I fill the mould with the plastic mass up to the height of the

page_text: sides, and draw out the rods g, h, i, so as to leave in the mass corresponding
holes.
To make weather and waterproof boards, I use specially prepared gypsum, in
addition to the ordinary burned and ground gypsum mentioned in the Patent
No. 17130. The latter is burned at a temperature of about 150° C. and still
contains about 10 per cent. of water, whereas the special kind of gypsum is burnt or
calcined in a kiln to red heat, thereby losing all its water and acquiring for its
subsequent treatment the properties of cement, that is to say, it becomes slow-
setting, waterproof, and weatherproof.
This slow-setting and cement-like gypsum, I mix with ordinary burnt quick-
setting gypsum in about equal parts, and proceed as described in the said Patent
Specification (page 3, lines 8-15 of the printed copy), or as described in the first
part of the present Specification.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is ;-
1. The manufacture of composite boards containing woven sheets embedded in
the plastic material, substantially as described and for the purpose specified.
2. Composite boards for building purposes, made with a mixture of ordinary
burned and ground gypsum and the specially prepared slow-setting gypsum described
above, substantially as described and for the purposes specified.
Dated this 21st day of July 1894.
FAIRFAX & WETTER,
433, Strand, London, Agents.