IMPROVEMENTS IN DIVIDING HARD SUBSTANCES, SUCH AS ROCK, STONE, OR COAL
Year: 1864

page_text: LETTERS PATENT to Robert William Thomson, of Edinburgh, in the
County of Mid-Lothian, North Britain, Civil Engineer, for the Invention
of "IMPROVEMENTS IN DIVIDING HARD SUBSTANCES, SUCH AS ROCK, STONE, OR
COAL."
Sealed the 13th December 1864, and dated the 16th June 1864.
PROVISIONAL SPECIFICATION left by the said Robert William Thomson
at the Office of the Commissioners of Patents, with his Petition, on
the 16th June 1864.
I, ROBERT WILLIAM THOMSON, of Edinburgh, in the County of Mid-Lothian,
North Britain, Civil Engineer, do hereby declare the nature of the said Inven-
tion of "IMPROVEMENTS IN DIVIDING HARD SUBSTANCES, SUCH AS ROCK, STONE, OR
COAL," to be as follows, that is to say:-
This Invention consists in dividing hard substances, such as rock, stone, or
coal, by means of bydraulic pressure. Water is the most convenient medium;
and pumps such as are used for hydraulic presses are the most convenient
means for imparting a suitable pressure to the water. The water is conducted
under great pressure through small pipes to one or more water-tight vessels or
spaces applied in drill holes formed in the ordinary way in the plane of
intended division of the rock or other body to be divided or split. The
water-tight vessels may be made of lead or other metal, or of rubber, gutta.
percha, or other elastic or flexible material, such as will permit the internal.
pressure to act on the sides of the spaces containing the vessels. It is

page_text: preferred to make the vessels of a flat form, and to dispose them in the drill
holes in the plane of intended division. After the water-tight vessels are
placed in their holes the space around or on each side of them may be packed
with sand or other material. When the water is forced into the water-tight
vessels under a suitable pressure they will expand and so divide or split the
rock, stone, coal, or other hard substance. A single drill hole with its
hydraulic wedge (as the water-tight vessel may be termed) may in some cases
be sufficient for the object in view; and the action may be assisted by
grooving the sides of the hole or holes and the surface in the plane of intended
division.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Robert William Thomson in the Great Seal Patent Office
on the 16th December 1864.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
WILLIAM THOMSON, of Edinburgh, in the County of Mid-Lothian, North
Britain, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixteenth day of June, in the year of our
Lord One thousand eight hundred and sixty-four, in the twenty-seventh year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Robert William Thomson, Her special licence that I, the
said Robert William Thomson, my executors, administrators, and assigns,
or such others as I, the said Robert William Thomson, my executors,
administrators, and assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend, within
the United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN DIVIDING HARD SUB-
STANCES, SUCH AS ROCK, STONE, OR COAL," upon the condition (amongst others)
that I, the said Robert William Thomson, my executors or administrators,
by an instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and cause
the same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Robert William Thomson, do hereby

page_text: declare the nature of my said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement in writing, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to say :-
My said Invention relates to the dividing of hard substances, such as rock,
stone, or coal, by means of hydraulic pressure. And for the purpose of prac-
tically carrying out my said Invention water is the most convenient medium,
and pumps such as are used for hydraulic presses are the most convenient
means for imparting a suitable pressure to the water. The water is conducted
under great pressure through small pipes to one or more water-tight vessels
applied in drill holes formed in the ordinary way in the plane of intended
division of the rock or other body to be divided or split. The water-tight
vessels may be made of lead or other metal, or of rubber, gutta percha, or
other elastic or flexible material, such as will permit the internal pressure to
dilate it and act on the sides of the spaces containing the vessels. I have
found from practical trials in splitting stone, that for that operation a water-
tight vessel of copper answers well, and I prefer to conduct the water to the
vessel through solid drawn copper tubing. The minor details of arrangements
and means to be employed in practising my said Invention are obviously
susceptible of very varied modifications, but one simple modification will
serve for illustration, and will enable those desirable of availing of the improve-
ments to put them successfully into practice.
Figures 1 and 2 on the accompanying Sheet of explanatory Drawings, are
sections at right angles to each other, showing a round hole A, formed in the
ordinary way in a block of stone B. A water-tight copper vessel C, which is
by preference of a flat form, is so placed in the hole as to be in the plane
D, D, of intended division. A copper tube E connects the water-tight
vessel C with any convenient kind of force pump. After the water-tight
vessel is placed in the hole, the space F around or on each side of it, and also
for a suitable depth above it, is packed with sand, cement, or other suitable
material, and the water is then forced in, when it causes the water-tight
vessel C to expand and divide or split the block B in which it is placed.
The depth of the hole A and the length of the water-tight vessel C may be
varied according to circumstances, and a single hole with its hydraulic wedge
C (as the water-tight vessel may be termed) may in some cases be sufficient
for the object in view, whilst in other cases it may be desirable to employ
two or more hydraulic wedges placed in holes at suitable distances apart.
The dividing action may also be assisted and directed by grooving the sides of
the hole or holes and the surface of the block in the plane of intended

page_text: division, and common wedges may also be driven in at suitable points for the
same purpose.
Having thus particularly described my said Invention, and in what manner
the same is or may be performed, I have to state that what I believe to be
novel and original, and claim as the Invention secured to me by the herein-
before in part recited Letters Patent is, the dividing of hard substances by
hydraulic pressure acting on water-tight expanding vessels placed within the
substances, substantially as herein-before described.
In witness whereof, I, the said Robert William Thomson, have here-
unto set my hand and seal, this Twelfth day of December, in the
year of our Lord One thousand eight hundred and sixty-four.
Witness,
EDMUND HUNT,
Patent Agent,
28, St. Enoch Square,
Glasgow.
R. W. THOMSON. (L.S.)