IMPROVEMENTS IN ROCK TUNNELLING AND IN MACHINERY EMPLOYED THEREIN."
Year: 1881

page_text: LETTERS PATENT to Herbert Newton Penrice, of Hatfield, in the County of
Herts, for an Invention of "IMPROVEMENTS IN ROCK TUNNELLING AND IN
MACHINERY EMPLOYED THEREIN."
PROVISIONAL SPECIFICATION left by the said Herbert Newton Penrice at
the Office of the Commissioners of Patents on the 13th May 1881.
HERBERT NEWTON PENRICE, of Hatfield, in the County of Herts. " IMPROVE-
MENTS IN ROCK TUNNELLING AND IN MACHINERY EMPLOYED THEREIN.'
"
This Invention has for its object improvements in rock tunnelling and in
machinery employed therein.
My rock tunnelling machinery is adapted to carry out my system of tunnelling,
which consists in producing a long cavity by the aid of an explosive and blowing
in the sides and then the roof by blasting charges inserted into 3 parallel holes
formed for the purpose.
Like other tunnelling machines previously constructed by me this machine is
intended to be actuated by compressed air. It comprises a bed frame on which
there is a motor engine and cylinders for imparting motion to rams carrying the
rock drills. The motor engine serves to turn a screw by which the machine is
moved forward to its work and drawn back, also to work the valves by which
compressed air is distributed to the drilling cylinders, and to impart, rocking
motion to the drilling tools.
In my present machine the drilling cylinders are fixed and their axes are
parallel. The ram for preparing the holes for the long "cavity is armed
with two drilling tools, one over the other, above and below the centre of
the ram.
Two holes are thus simultaneously produced by the one cylinder.
When
charged from their proximity they explode together, breaking into one another;
a second discharge produces the "long cavity." The sides of this cavity are
weak to resist the charges in the side holes. Two separate cylinders may be
used.

page_text: The drilling cylinders on each side of and above the bed frame each carry one
drilling tool placed eccentrically and close into the angle of the tunnel. From the
eccentric position of these drilling tools it results that when the charges are fired
in the holes the rock is cleared out of the way of the cylinders, leaving no impedi-
ment to the forward movement of the machine. The machine is provided with
wheels and moves forward along rails laid for it.
The drilling tools may be ten or twelve feet long, or even longer.
Their heads are formed with cutting edges in the form of a cross.
When at
work they are turned through an arc of 45 degrees between the blows. To keep
the hole round each radial cutting edge has at its extremity a short length of
circumferential edge set back somewhat from the radial edge, so that the heavier
work may fall on the radial edges. A small copper tube is inserted in the drilling
tool nearly up to the cutting edges, and delivers a jet of water under pressure
which clears tho debris out of the hole.
I prefer to employ for admitting air to the drilling cylinders piston valves having
alternate admission and exhaust ports on one side. This is an equilibrium valvo
giving two admissions and exhausts for each reciprocation of the valve.
All the handles for working the machine are at the front next to the work;
by them the admission to each cylinder can be separately regulated and the forward
and backward movement of the machine controlled.
When the machine has done its work at the face it is run back and into a siding
in an enlarged part of the heading, where it remains whilst the blasting and clearing
away operations are in progress.
During this time the machine is employed in drilling the holes for the enlarge-
ment, three out of the four drilling cylinders being employed for this purpose.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Herbert Newton Penrice in the Great Seal Patent Office on the
13th November 1881.
" IMPROVE-
HERBERT NEWTON PENRICE, of Hatfield, in the County of Herts.
MENTS IN ROCK TUNNELLING AND IN MACHINERY EMPLOYED THEREIN."
This Invention has for its object improvements in rock tunnelling and in
machinery employed therein.
My rock tunnelling machinery is adapted to carry out my system of tunnelling
which consists in first producing (or disintegrating the material in) a long cavity
close down to the floor of the tunnel to be formed, and then blowing in the sides
and the roof by blasting charges inserted into three parallel holes formed for the
purpose.
Like other tunnelling machines previously constructed by me this machine is
intended to be actuated by compressed air. It comprises a bed frame on which
there is a motor engine and cylinders for imparting motion to rams carrying the
rock drills. The motor engine serves to turn a screw by which the machine is
moved forward to its work and drawn back, also to work the valves by which
compressed air is distributed to the drilling cylinders and to impart rocking motion
to the drilling tools.
In my present machine the drilling cylinders are fixed and their axes are parallel.
The ram for preparing the holes for the long "cavity" is armed with two or more
(by preference four) drilling tools to drill two or more (by preference four) parallel
holes in proximity to one another at distances from the centre of the ram,
Two or more holes are thus simultaneously produced by the one cylinder. If
two only are used I form them one over the other. When the holes are charged
and exploded together they by reason of their proximity break into one another
and so produce a long and partially filled cavity with the material therein more or
less disintegrated.
The sides of this partially filled cavity are weak to resist the subsequent
explosion of the charges in the side holes. Separate cylinders may be used for
each drill if preferred, or two cylinders might be used, each carrying a pair of
drills.
The drilling cylinders on each side of and above the bed frame each carry one
drilling tool placed eccentrically and close into the angle of the tunnel. From the
eccentric position of these drilling tools it results that when the charges are fired
in the holes the rock is cleared out of the way of the cylinders, leaving no
impediment to the forward movement of the machine.
The machine is provided with wheels, and moves forward along rails laid for it.
The drilling tools may be ten or twelve feet long, or even longer.
Their heads are formed with cutting edges in the form of a cross.
When at
work they are turned through an arc of 45 degrees between the blows. To keep
the hole round each radial cutting edge has at its extremity a short length of
circumferential edge set back somewhat from the radial edge, so that the heavier
work may fall on the radial edges.
A slot is formed along the stem of each drilling tool, into which a small copper
tube is inserted nearly up to the cutting edges; this small copper tube delivers a
jet of water under pressure into the bore hole to force out the debris from it.
Water under pressure is supplied to the copper tube through a flexible tube
attached to its rear end.
I am able to supply the water under pressure in this way, as the drilling tools
have a rocking motion given to them and not a revolving motion.

page_text: I employ for admitting air to the drilling cylinders piston valves having
alternate admission and exhaust ports on one side. This forms an equilibrium
valve giving two admissions and exhausts for each reciprocation of the valve.
All the handles for working the machine are at the front next to the work; by
them the admission to each cylinder can be separately regulated, and the forward
and backward movement of the machine controlled. One man alone can thus work
the machine by himself and effect the putting in of the several holes.
When the machine has done its work at the face it is run back and into a siding
-in an enlarged part of the heading, where it remains whilst the blasting and clearing
away operations are in progress.
During this time the machine is employed in drilling the holes for the
enlargement, three out of the four drilling cylinders being employed for this
purpose.
In order that my said Invention may be most fully understood and readily
carried into effect, I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a side elevation, and Figure 2 a plan partly in section, of a rock
tunnelling machine constructed according to my Invention; Figure 3 is an end
elevation, and Figure 4 a vertical cross section of the same.
Figure 5 shows on a larger scale side elevation of the machine with some of the
parts in section. The details of the several parts of the machine are best seen in
this Figure.
a, a, is the bed of the machine; it is provided with wheels b, b, to run upon
rails c, c.
The frame has fixed upon it the three air cylinders d, d, d, and a
fourth cylinder d is carried upon a standard a springing from the frame a.
Within each cylinder there is a piston from which a ram projects out through a
stuffing box.
The annular space in front of the piston is constantly in communication with
the air supply, and a valve operates to alternately admit compressed air behind the
piston, and then to open a passage for its free escape.
In this way the piston is caused to reciprocate several hundred times a minute.
The drills for forming the three corner holes are fixed upon tool holders e, e, e,
which are mounted so as to slide in parallel guides a³, a², a³, on the frame, the
upper guide being mounted upon the standard a³×.
The cutting head of each drill is made in the form of a cross, as shewn at
Figures 12 and 13. Each radial cutting edge has at its extremity a short length
of circumferential edge projecting on either side of it, so that when the tool is
turned through an arc of 45° between successive blows a circular hole will be
formed.
The tool heads are, as shown at Figure 12, held in sockets at the ends of the drill
stems, and are secured therein by a key passed through them; the key is secured
by a small wire passed through its end and twisted together.
The stems of all the drills are slotted, as above described, from end to end. A
copper pipe e¹ is laid along the groove and is secured therein by closing inwards the
edges of the groove.
The end of the pipe e' next the drill is open to allow water to be projected from
it, as shown at Figure 13; the rear end of the pipe has a nozzle projecting from
it, to which is secured one end of a flexible pipe, the other end of the flexible pipe
being secured to a nozzle through which water under pressure can be supplied
to it.
The guides a for the tool holders are not concentric with the cylinders d, but
are set more into the angle of the tunnel in process of construction. The line fin
Figures 3 and 4 indicates the sectional form of this tunnel. The heads of the rams
are formed with sockets in them, which are eccentric to the ram but aligned with
the hole to be bored.

page_text: Each tool holder is formed with a stem to enter the socket in the ram, and it
turns in the socket in consequence of the rocking motion which is imparted to
the tool holder for the purpose of turning the drill in the hole. This motion,
which is imparted by the eccentric g, extends 'over 45 degrees of angle, and the
blows are struck when the tool holder arrives at the end of its rotary
movement.
The tool holders are grooved where they pass through the sleeves or guides a²,
which are free to rock in bearings, as shewn, and a projecting key in the guide
entering the groove causes the tool holder to turn with the guide.
Each guide a has an arm fixed upon it, and rods from the eccentric g are jointed
to these arms. The eccentric g is upon an axis h, which also carries the eccentric i
working the valves for admitting air to the cylinders d, d.
Figures 14, 15, and 16 shew views of one form of the piston valve. Air under
pressure is admitted to the valve continuously by the pipe A, and is conducted by
the passage B continuously to the annular end of the cylinder. The valve is shewn
in its central position; in this position the ports C leading into the opposite end
of the cylinder are open to the exhaust, as shewn, but when the valve is moved
endwise in either direction the ports Care closed to the exhaust, and air under
pressure is admitted to them. The number of ports C formed through the cylinder
end may be varied; three are shown in the Drawing.
For each cylinder d a stop cock is also provided by which the supply of air
can be turned on and off at pleasure. These cocks are worked by handles at the
front of the machine; is a clutch also having a handle at the front of the machine;
it serves to clutch the axis h with the axis when it is desired to set the drills to
work. The axis is rotated by the three cylinder air engine m; the air cock
admitting air to this engine can be turned in order to start and stop the engine by
means of the hand wheel m' at the front of the machine.
The forward movement of the machine is obtained by means of the worm n,
which a friction clutch operated by a hand wheel at o clutches when required to
the axis ; so it will be seen that all the handles necessary to work the machine are
at the front, where it is convenient that the workman should stand close to the
face where the drills are at work.
The worm n gears with a worm wheel p, as is better seen in Figures 5 and 6,
and on the same axis with the worm wheel there is a bevilled pinion q driving a
corresponding pinion upon the screw 7, which works in a nut firmly fixed in rear
of the machine, and which forms the abutment.
The cylinder d which operates to produce the primary "long cavity," and which
is the centre cylinder in the bottom row, I make of somewhat larger size than the
other cylinders, and I provide its ram with two or more (by preference four) tool
holders; and if two only are used I place them one above the other, as before stated.
The tool holders carry drills like the others, and two or more parallel drill holes
are produced close together in the face of the rock.
The machine produces all the holes simultaneously, but this pair or greater
number of holes is first charged and fired, when, as before stated, the discharge
blows the two or more holes into one, and so disintegrates the material between
them. The two side holes are then charged and fired, and finally the top hole which
brings down the roof.
The holes might all be charged at the same time, and provision made for ensuring
that the charges in the several holes employed for forming the cavity should be
first fired, and afterwards the charges for blowing in the sides and material from
the roof.
The same machine slightly varied to adapt it for boring a vertical shaft is shewn
at Figures 7, 8, 9, 10, and 11. Figure 7 is a side elevation; Figure 8, a plan;
Figure 9, a horizontal section of the machine; Figures 10 and 11 shew plan and
side elevation of apparatus for fixing within the shaft a screw nut from which the
whole machine is suspended.
As the Drawings shew the machine is constructed to bore an assemblage of

page_text: 4 holes X at the centre of the shaft, and four other holes Y, Z, at distances from
this assemblage. Charges in the four holes X are first exploded, then charges in the
pair of holes Y which are nearest to the hole X and subsequently charges in the
hole Z, so making a shaft approximately of the form shewn; this shaft can then be
subsequently enlarged to a circular or other section.
The drill stems are, as in the machine first described, eccentric to the rams of the
air cylinders that work them; they are also rocked through an angle of about 45°
in the same way.
The valves by which air is admitted to and allowed to escape
from the air cylinders are worked from an eccentric g on a revolving shaft driven
at a high speed by a small engine.
The mechanism for lowering the machine as the drilling goes on is also the same
as that used in the other for feeding the machine forwards, and is effected by turning
the screw in the manner described.
The screw screws through a nut fixed in the shaft above the machine. Figures 10
and 11 shew how the nut may be fixed in the shaft.
Having thus described the nature of my Invention, and the manner of per-
forming the same, I would have it understood that I claim, the improved rock
tunnelling machine, substantially as herein before described.
I also claim the arrangement of the cylinders & fixed in the machine and parallel
the one to the other, and drills eccentric to them, as described.
I also claim the arrangement of the machine with two or more drills close
together producing the long cavity, as described.
I also claim the method of tunnelling by drilling two or more holes close together
and three other parallel holes, one on either side and one above, and firing charges
in such holes so as to produce first the "long cavity," and to blow in the sides and
then the roof, as described.
I also claim forming a slot along the stem of each boring tool, and laying a tube
therein, through which a jet of water may be projected into the bore hole, such
tube at its rear end being connected by a flexible tube with a supply of water
under pressure by a flexible tube, which allows of the tool being rocked through
the arc of a circle, substantially as described.
I also claim the boring tool, substantially of the form shewn at Figures 12 and
13, rocked through an arc of about 45° between successive blows.
I also claim the use of a piston valve, substantially of the construction described,
for admitting air under pressure to the cylinders which actuates the boring tools,
such valve being formed to give two admissions of air and two exhausts for each
reciprocation of the valve.
In witness whereof, I, the said Herbert Newton Penrice, have hereunto set
my hand and seal, this Ninth day of November, in the year of our Lord
One thousand eight hundred and eighty one.
H. N. PENRICE. (L.S.)