AN IMPROVED METHOD OF AND MACHINERY FOR CUTTING AND EXCAVATING ROCK FOR RAILWAY TUNNELS AND OTHER PURPOSES
Year: 1865

page_text: PROVISIONAL SPECIFICATION left by George Haseltine at the Office of
the Commissioners of Patents, with his Petition, on the 12th June 1865.
-A communication from abroad by Thales Lindsley, of Rock Island,
Illinois, United States of America.
I, GEORGE HASELTINE, of the "International Patent Office," No. 8, South-
ampton Buildings, Chancery Lane, in the County of Middlesex, Civil Engineer,
do hereby declare the nature of the said Invention for "AN IMPROVED METHOD
OF AND MACHINERY FOR CUTTING AND EXCAVATING ROCK FOR RAILWAY TUNNELS
AND OTHER PURPOSES," a communication, to be as follows:-
The object of this Invention is the formation of tunnels and other like
excavations in rock, without the employment of gunpowder or other explosive
material; and said Invention consists of boring machinery arranged to cut
anuular grooves or recesses in the rock, combined with the means for splitting
off the isolated portions of said rock remaining between the anuular grooves
or recesses formed by the boring tools; the motive power employed to actuate
the said machinery being compressed air. The operation of cutting the
annular grooves in the rock is performed by means of a number of chisels set
in a revolving cutter head or frame placed on the front end of a horizontal
bar, and made capable of rotating with said bar, or being disengaged therefrom
when required; this bar turns in suitable bearings fixed on the framing of the
machine, and is made capable of sliding endwise in said bearings. On one
end of this bar is a strong cross piece or head forming the ram for driving in
the wedges employed for splitting the rock, and on the rear end of said bar a
screw is formed. This end of the bar is connected to a strong cross head

page_text: attached to the piston rods of two horizontal cylinders securely nxed to, and
forming a portion of the framing of the machine. The end of the horizontal
bar passes through a boss or eye in the centre of the cross head, and is made
capable of turning freely or sliding endwise in said boss or eye, and is adjusted
and held in the required position by a nut on each side of the cross head.
The piston rods of the cylinders work through stuffing boxes in the end of
said cylinders, and the pistons are fitted to work perfectly air-tight, and are
moved in the required direction by the force of the compressed air admitted
into the cylinders. The horizontal bar is turned in its bearings by means of a
worm wheel connected by suitable gearing with a countershaft, and this
countershaft receives motion from the main or driving shaft of the machine;
the relative velocities of these two shafts being varied as required by means of
conical gearing. On the main or driving shaft are cranks connected to the
piston rods of a pair of oscillating cylinders working on trunnions fixed to the
framing of the machine and driven by the force of compressed air. The worm
wheel is fixed on a sleeve or boss, and in this sleeve is fitted a key or feather
made to slide in a groove or channel formed on the screw end of the horizontal
bar parallel with the axis thereof, so that the bar can slide freely endwise while
being rotated by means of the worm wheel and gearing in connection there-
with. A nut is fitted on the screw end of this bar, said nut having a worm
wheel on its exterior; this worm wheel and nut receive motion from a worm
or screw fixed on the end of a diagonal intermediate shaft, and said inter-
mediate shaft is connected by suitable gearing to the main or driving shaft.
The wheels composing this gearing are capable of being changed in order to
the number of revolutions of the nut; the rate of motion of the bar
endwise, during the operation of boring, being regulated by the velocity of
said nut.
The countershaft is capable of being thrown out of gear with the
driving shaft by a sliding clutch or other suitable device; and at the same
time by means of the said sliding clutch, the driving shaft is thrown into
gear with the nut, the wheels composing this gearing being arranged to
work in such a direction and at such a relative velocity as to revolve the
nut quickly and move the bar and cutter head rapidly back free from
the portion of rock being operated upon; and the bar is retained in the
required position by means of a pawl or catch on the framing of the machine.
Each of the chisels set in the cutter head is drawn back in succession during
the operation of boring by means of a cam fixed just behind the cutter head,
and the chisels are kept in contact with the surface of the rock when released
This cam advances
from the cam by spiral springs or other suitable means.
endwise with the cutter head and receives its motion by means of suitable
vary

page_text: gearing from the countershaft.
Another cam is fixed behind the cutter head to
operate a chisel set radially towards the central axis of the horizontal bar. This
chisel is for the purpose of cutting a channel or watercourse in the bottom of the
tunnel, and is fixed in the socket of a frame attached to the projecting ends of the
plungers of the horizontal cylinders. The frame carrying the chisel advances
with the horizontal bar and cutter head during the operation of boring, and is
prevented by said plungers from rotating with the horizontal bar. The feet of
the framing of the machine are provided with rollers to enable the machine to be
easily moved forward as the tunnel is formed; and in order to fix the machine
firmly in position during the several operations wedges or keys are driven
tightly between portions of the framing and the sides of the tunnel. The
compressed air for actuating the machine is condensed by any efficient means,
and is contained in receivers or reservoirs of any suitable form and construction,
communicating by pipes and other like connections with the cylinders fixed on
and forming part of the machine. The machine when in operation is placed
with the cutter head facing the portion of rock to be excavated. The compressed
air is admitted into the oscillating cylinders connected to the main shaft. The
cutter head or frame holding the chisels is thrown into connection with the
sliding bar and is caused to revolve thereby. The boring is continued till the
required depth is given to the annular grooves or recesses in the rock, the
cutter head and bar are then drawn back and the cutter head is disengaged
from the bar. The wedges for splitting the rock are then placed in the
required position in the annular grooves or recesses formed therein, the pawl
holding the sliding bar is thrown up and the bar is released. The compressed
air is then admitted behind the pistons of the horizontal cylinders, and drives
the head of the bar forcibly against the ends of the wedges placed in the
annular grooves or recesses, thus splitting off the portions or rings of rock not
removed by the boring tools. The detached portions of rock are then removed
through apertures left in the framing and other portions of the machine for
that purpose. The tunnel being ventilated during the process of excavation
by the air escaping from the cylinders and other parts of the machine.