IMPROVED MACHINERY FOR CUTTING TUNNELS, AND SINKING SHAFTS
Year: 1865

page_text: PROVISIONAL SPECIFICATION left by Alexander Alison and Henry
Hoskings at the Office of the Commissioners of Patents, with their
Petition, on the 15th November 1865.
We, ALEXANDER ALISON, of 41, York Terrace, Regent's Park, in the
County of Middlesex, Gentleman, and HENRY HOSKINGS, of Hayle, in the
County of Cornwall, Engineer, do hereby declare the nature of the said
Invention for "IMPROVED MACHINERY FOR CUTTING TUNNELS, AND SINKING
SHAFTS," to be as follows:-
Our Invention consists of machinery for cutting or excavating tunnels and
shafts, and may be thus described:-There are two, three, or more discs with
chisels and a similar number of discs with inclined planes, each chisel disc
having an inclined plane disc opposite to it of the same size, and the action of
the chisels on the inclined planes produces the percussion of the chisels against
the rock which cuts the tunnel. The machine is constructed on a framework
which rests on wheels of which a hollow tube running lengthways is the main
stay. Through this hollow tube the main driving shaft of the machine works,
which shaft is connected with the motive power at the one end, and the
inclined plane discs at the other. There are three motions, first, the quick
motion of the inclined plane discs which works the springs for shooting the
chisels; second, the general revolution of the combined chisel discs, which is a
slow motion; and, third, the particular motion of each of the chisel discs, which
is likewise a slow motion. The main driving shaft turns rapidly and works

page_text: the inclined planes; off this shaft is a series of pinion toothed and worm wheels
with driving shafts, which reduces the speed and produces the general revolu-
tion. The inclined planes, which are double, come against the chisel rods, on
which rollers are placed; the travelling of the rollers on the inclines draws
up or compresses the springs which are fixed around the chisel rods, and when
the rollers reach the end of the inclined planes the chisels are projected against
the rock with great force. In the centre of the hollow shafts on which the
chisel discs revolve is a jet of water for softening the rock and carrying away
the debris, which will be in the shape of sand. The tubes which carry this
water are shafts for the revolution of each of the chisel discs by means of
pinions and toothed wheels on the face of the disc. Outside of these tubes or
shafts are hollow shafts or tubes which are a fixture or part of the framework.
The chisels are removeable at pleasure, so that they may be sharpened as often
as may be required, and should be made of the hardest steel that can be
procured. A fixed or locomotive engine or any other motive power may be
employed. A screw lever or other mechanical device may be used to force
the tunneling machine forward as the cutting proceeds.
Our Invention as now described is suited for tunnels of any size, and will
cut through soil or rock of any hardness. It is likewise suitable for sinking
shafts through soil or rock of any kind; also for cutting levels, and for mining
metallic bearing quartz, and other minerals. Where the tunnel is large, we
recommend that more than three discs be used, and where increased speed is
wanted we recommend that more than one row of chisels be used.
The object of having more than one disc is that the chisels may not run in
one groove, but pass over the whole area of the tunnel in a series of circles; and
we recommend that one disc should be larger than the others, so that no core
in the centre may be left. It must, however, be understood that we do not
confine ourselves to the exact details herein given, but to the general principles
upon which our Invention is based.
Our Invention of a complete tunnel cutting machine offers great advantages
over a mere drilling or boring machine like that in use at Mont Cenis and
elsewhere. First, our machine requires no powder for blasting, the explosions
and smoke occasioned by which cause great loss of time and hinderance to the
work; second, our machine is self-cleansing and does not require to be stopped
so that the debris may be taken away by hand labour; third, the work done
by our machine is much better than where powder is used, as the sides of the
tunnel are cut quite smooth and not shivered by blasting, which not only
weakens the tunnel, but admits water at all points; fourth, the cost of
tunneling by our machine will not be one-fourth compared with that of hand

page_text: labour or boring machines, while the time required for the execution of the
work will be reduced in a similar ratio.
Not only will our tunneling machine facilitate the cutting of tunnels through
the Alps and other mountain ranges, but it will be available for tunnels under
the estuaries of rivers and channels of seas, such as a tunnel between Calais
and Dover to connect England with the Continent by rail, and from Port
Patrick to Donaghadee to connect Great Britain with Ireland. In short it
will render practicable with a reasonable expenditure of capital many
engineering problems which have hitherto been considered practically im-
possible owing to the vast expenditure of time and money which they involved
from the want of a serviceable tunnel cutting machine, such as that now
invented.