A New or Improved Process for Working Stone, Marble, Granite and the like."
Year: 1897

page_text: Date of Application, 4th June, 1897-Accepted, 18th Dec.,
1897
COMPLETE SPECIFICATION.
"A New or Improved Process for Working Stone, Marble, Granite
and the like."
I, CARL HERGENHAHN of 58 Mundenheimer Landstrasse, Ludwigshafen a/Rh in
the Empire of Germany, Proprietor of stone quarries, saw mills, grinding mills
and stone mason's yards, 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 a new method of producing marble work and stonemason's
work which has hitherto been produced by the stonemason and marble cutter or
by machines in substitution thereof by means of saws, chisels, picks, cutters,
files, and other metallic tools.
As is well known, natural stones are obtained from the quarries by the quarry-
men or stone cutters and are roughly cut and shaped into blocks and pieces to
approximate dimensions in the same manner as the wood-cutters shape the logs
and trunks of trees in the forest according to the uses to which they are to be put.
The stonemason who requires a preparatory shaping of this kind begins the
stone-mason's work proper by forming the said pieces with sharp edges and
straight surfaces accurately to measurement and drawings. He then works out
the shapes of the cornices or the like in a proper manner by means of chisels,
hammers, files, &c. The work produced in this manner with chiselled and chipped
front faces constitutes finished stonemason's work and is mostly employed in such
a condition. The said faces or surfaces which are to be displayed are worked,
according to the purposes to which they are to be put, with more or less rough-
ness or fineness and the finest work is that which is the last stage before grinding
and which is employed for articles which are to be further ground and polished.
The marble cutter and stonemason's work which has thus been brought to a
finished state is then, if necessary, ground and polished on its visible faces by other
workmen. This does however not effect any change of shape but has merely
for object to render the surfaces or cornices more smooth and polished in the
same manner as is produced by the polishing of furniture or the like. The grind-
ing or polishing is in both cases not a means for shaping and has not for object
to produce the shape of articles; this is done by the stonemason the same as is
done by the joiner.
The products of the stone and marble industry can be divided into solid and
plated work. In the former case the work must be treated on all sides by, stone-
masons and it constitutes the stonemason's work proper. In the latter case the
work is merely shaped along its edges and joints and this process is specially
employed in the marble industry in which most blocks are sawn into plates which
are worked up into table plates, washstands, the treads of stairs, and floor coverings,
wall coverings, fireplaces, tablets for inscriptions and the like. Both the tools
of the stonemason and the mechanical grinding apparatus are made of metal and
in the latter case sand, pumice stone, and emery is supplied by means of water.
The straight joints in plate work have already been made in the rough upon

page_text: grinding discs composed of cast iron and having a smooth surface by means of
quartz sand and water.
Now the novelty of the present invention consists in effecting the shaping of
marble work and stonemason's work, which has been heretofore effected by
the stone mason or by machines in substitution for his labour, by grinding the
rough stone hewn or dressed as it comes from the quarry, that is to say this
invention consists in producing marble work and stonemason's work by grinding
and also whilst thus shaping, producing a ground, and if desired, a polished article.
In addition to this entirely new object and technical results there are employed
in this new process very considerably modified apparatus and new means of
grinding which have not been heretofore employed in stone working and which have
been improved and discovered by the inventor for use in said process. Whereas
the grinding apparatus heretofore employed consisted solely of metal discs or
the like and were quite smooth, the inventor employs rough unturned large
grinding discs, not merely composed of cast iron, but also such which are composed
of steel such as cast steel and having their surfaces grooved or fluted if necessary.
The smaller profile-cutting or milling discs and rollers have also their operative
surfaces grooved or perforated or hollows filled with grinding agents for the pur-
pose of more effectively feeding and holding the latter. Further these grinding
discs, rollers or wheels are also made of the grinding agents, especially for working
plates and cutting out cornices. The grinding agents employed by the inventor
are Carborundum, metal grit," emery, and similar sharp substances.
The process for producing or shaping
(1) Solid work is effected as follows:-
(a) On their straight surfaces by placing the rough quarry-dressed pieces
(such as they are required also by the stone mason) upon a large horizontal
revolving wheel, or by pushing the same against vertical and if necessary
adjustable wheels and rollers which are caused to revolve and which act upon
the surfaces with grinding agents.
(b) Cornices and facade pieces are also produced by means of a smaller
and suitably shaped revolving discs or rollers.
(c) Round articles are mounted in between two spindles and caused to
revolve, and either suitably shaped grinding irons or discs and rollers (also
revolving) are brought up against the stone so as to grind out the shape of
the article. If these grinding devices are made of metal, special grinding
agents are supplied by means of water. When they are composed of the
grinding materials themselves, water only is required.
or
(11) Plate work is treated along the joints and edges, as are also panels and
cornices, by means of suitably shaped rotating grinding discs, wheels
rollers of grinding materials such as Carborundum, emery, or other similar sharp
substances and are thus brought to the shape required by the measurements and
drawings. All the apparatus are driven by power. In this manner all or several
stages of the stonemason's work for shaping purposes can be saved, and this
process constitutes a mechanical substitute which has been long sought for, but
not yet attained, for the work of the stonemason and which even excels the latter's
work. As already stated, simultaneously with the shaping according to this
process, a ground article is produced whereas the stonemason produces only chipped
or chiselled faces. Further the cost of manufacture of the articles is reduced by
about 80%. In this manner the articles can be made more cheaply and can be
employed to a far greater extent than hitherto.
The stone-working industry will thereby assume far greater dimensions, because
large factories can be established which hitherto were not remunerative and could
not be compactly controlled on account of the large amount of hand labour whereby
the industry remained on the level of a small handicraft. The labour of the work-
men employed therein is facilitated and in hygienic respects it is a considerable
improvement because with this new process no dust is produced which has hitherto
rendered stonemasons prematurely consumptive and killed them off at an average

page_text: age of 40 years. The invention and means of producing stonemasons work of
shaping by means of grinding in a much better degree and more cheaply than
has been done for thousands of years is the more important because in spite of
the great age of this industry nobody before to-day has thought of it; otherwise
the great financial advantage would long ago have brought the process into practical
This is proved also by the whole literature of the stone-working industry
and of its special trade journals, in which only the old method has been described
and in which granite monuments from Sweden &c. chipped ready for grinding are
offered for sale.
use.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is: :-
(1) A new or improved process for shaping or producing all kinds of work
from rough hewn or quarry-hewn stone, marble, granite, or the like, consisting
essentially in producing the desired shapes, solely by grinding, the process being
such that in all the working operations, the surfaces as well as the edges are
treated only by means of revolving grinding discs which are driven by power and
which are provided in a suitable manner with grinding or abrading material,
substantially as described.
(2) A process for working stone and the like substantially as hereinbefore
described.
Dated this 4th day of Tuna 1807
ROBERT. E. PHILLIPS, Assoc. M. Inst. C.E., M.I. Mech. E.
Consulting Engineer & Patent Agent,
70, Chancery Lane, London, W. C., Associate Agent.